SpaceX lands rocket at sea second time after satellite launch - <AUTHOR> http://phys.org/news/2016-05-spacex-successfully-rockets-stage-space.html <comment><USER3> For those wondering, this isn't a simple repeat of CRS8 which landed on a drone ship about a month ago. CRS8 was a mission to low earth orbit which left the first stage with plenty of fuel to effect a landing. The landing was made as slow as possible and limited only by how low a single engine could be throttled. The re-entry burn which slows the rocket down before the landing burn was also more agressive.

This mission was to launch JCSAT-14 to geosynchronous orbit which requires the falcon 9 to move the already heavy satellite into a geosynchronous transfer orbit. That meant the first stage had to do a lot more work and was left with a lot less fuel as a result. Therefore, the re-entry burn was less aggressive, the first stage came in with twice the speed, and SpaceX needed to do a far harder landing with three engines lit in the quicker and riskier suicide burn. Somehow, despite playing down expectations, they managed an even more precise landing than last time.

<comment><USER4> From the video it looks like it lands on a ship in rough seas and they do nothing to secure it. Won't it just fall over if the seas are rough enough, and if so, why don't they have some sort of robotic system that locks it down tight the moment it lands?

<comment><USER5> All of the centre of gravity is low down with the engines. The rest is basically just a thin empty tube.

<comment><USER6> To add to above: In the previous barge landing they did weld the landing legs to the barge using some kind of bracket. But they discovered that the centre of gravity is low enough to not need any welding. During the previous attempt the sea was heavier than this time.

Maybe they still weld it this time, but that is done by having someone go to the barge and do it.

<comment><USER7> Actually no they did not weld anything to the legs. Elon said that they realize it wasn't needed. They did use octojack though to support the weight off the legs.

<comment><USER8> What's octojack? Can't seem to find any other references to that.

<comment><USER7> Sorry meant Octoweb jacks

[https://imgur.com/5GTW1CO](https://imgur.com/5GTW1CO)

</comment></comment></comment></comment></comment></comment></comment><comment><USER9> What's notable about this attempt (as opposed to the last) is that the first stage rocket was traveling twice as fast (4x the energy to overcome on landing), and didn't have enough propellant to do a 'boostback' burn.

Instead, coming in very hot, the rocket had to use three engines (instead of one) to slow for landing. The last time this was attempted, the first stage put a nice hole in the deck of the drone ship.

Seeing the rocket dead-center on the barge was quite a sight!

<comment><USER10> One of my favorite facts is that merely relighting the engine provides enough thrust to lift the rocket (at its minimum throttle of 60%).

This means that it must slow to a standstill, cut the engines and hit the platform at exactly the same time or it will either start going up again or be dropped onto the platform from a less than ideal height.

<comment><USER11> This maneuver (powered descent with high deceleration right before impact) is called a "suicide burn"!

</comment></comment></comment><comment><USER12> Hosted webcast: [https://youtu.be/L0bMeDj76ig](https://youtu.be/L0bMeDj76ig)

Landing at 38:18mins [https://youtu.be/L0bMeDj76ig#t=38m18s](https://youtu.be/L0bMeDj76ig#t=38m18s)

Great info on the thrusters on the first stage at 19:37. [https://youtu.be/L0bMeDj76ig#t=19m37s](https://youtu.be/L0bMeDj76ig#t=19m37s)

Edit: Thank you and sorry about the time stamp link, I posted quickly from my phone. Hopefully it works on shortlinks.

<comment><USER13> You link directly a specific place by adding this to the URL: #t=38m18s

<comment><USER14> you can also make it a query parameter, which often works better. E.g. [https://youtu.be/L0bMeDj76ig?t=38m18s](https://youtu.be/L0bMeDj76ig?t=38m18s)

</comment></comment></comment><comment><USER15> Webcast - [https://youtu.be/L0bMeDj76ig](https://youtu.be/L0bMeDj76ig)

First stage landing is just after 38 minutes - [https://youtu.be/L0bMeDj76ig?t=38m](https://youtu.be/L0bMeDj76ig?t=38m)

</comment><comment><USER16> Doing it one time is a technological leap.

Doing it twice in such a small window of time is a logistical/programmatic leap.

<comment><USER17> Were they different rockets? If so I don't see the logistical leap.

<comment><USER18> Different use cases. This was a GTO launch which means the first stage had way more energy and therefore way tighter margins than the last attempt. This attempt used three engines to land and had a more difficult landing trajectory.

</comment></comment></comment><comment><USER19> Looks like the landing was perfectly centered on the barge this time as well. Does anyone know when they plan on reusing one of these recovered first stages?

<comment><USER20> They said at the beginning of the live stream that they plan to do a test fire on the first recovered first stage "sometime soon".

<comment><USER21> The first recovered stage, F9-021, has already been static fired and will likely end up as a monument outside of SpaceX HQ as they've filed an FAA request to do so.

[https://oeaaa.faa.gov/oeaaa/external/searchAction.jsp?action...](https://oeaaa.faa.gov/oeaaa/external/searchAction.jsp?action=displayOECase&oeCaseID=277099798&row=292)

The second recovered rocket, F9-023, will be relaunched. It has already been static fired with no announced problems. Elon said it'd be a few months before a customer was announced, but the general feeling is that it will be an SES satellite as SES has already publicly expressed interest.

<comment><USER22> Do customers get a discount for launching on a used rocket?

<comment><USER23> The first one definitely will (unless negotiations break down and they decide to launch without a customer, but that seems unlikely). Eventually when it becomes routine maybe not.

<comment><USER24> When it becomes routeine all clients get a discount as price per launch goes down.

<comment><USER22> Or not, because the next best alternative is much more expensive than SpaceX's current pricing.

We're dealing with a corporation -- I'm not sure we can count of them to "pass on the savings".

<comment><USER25> We're dealing with a group of people with strong ideas about space. They probably won't pass on much of the savings, but for a different reason - <USER2> need the budget for Mars project. That's the _whole purpose_ this company exists in the first place.

<comment><USER26> If they're smart (and they are) they'll figure out ways to reduce the price of launch in the right way to maximize an increase in their margins. They could more than double the number of customers using secondary space in the "trunk" and cube-sats. The secondary customers will pay far less than the primary ones, but there will be many more of them.

If they're smart, they're figuring out ways they can own a big part of the infrastructure for an emerging market.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER27> How are non-US space agencies and companies (like ESA, Russia, Japan, China, etc) reacting to the SpaceX and Blue Origin achievements?

Are they also testing similar things but we aren't hearing? Or they aren't threatened by the advances?

<comment><USER28> I attended a conference from the head of the CNES (Centre National d'Etudes Spatiales, ~ French NASA) in Paris a week ago and he talked about that.

Ariane 6 is going to be built with a cost effective approach and trying to focus on market needs (3D printing of parts, reusability of the first stage, etc.)

At first, concerning SpaceX, his group of experts told him that the design of the rocket wasn't going to work and was going to explode at high altitude due to fluctuation. They also told him that the first stage would just go through the barge, sinking both the first stage and the barge. Now they are taking new entrants way more seriously.

<comment><USER29> I can't imagine how anyone with the slightest clue could conclude that the first stage would sink the barge. The scales are just too different; the barge outweighs the rocket by orders of magnitude.

I hope this is one of those "lost in translation" things, because otherwise I fear for that group of supposed experts.

<comment><USER30> > the barge outweighs the rocket by orders of magnitude

The energy amount the rocket impacts with is dominated by its speed, not its mass. A small, fast-travelling projectile can make a hole in just about any kind of armour. The terminal velocity is quite low, but that's in part because of the way it is engineered — an ICBM would probably be able to put a hole through a ship deck with ease.

There is a lot of reasoning by analogy vs. reasoning from first principles going on, and the latter seems to be winning. But the main driver of the space industry is governmental funding, not commercial. Much of those statements were probably political; SpaceX have prevailed, and indeed found some champions of their own (John McCain is rabidly behind them, and some of the statements he comes up with are ludicrous in their own right, for example), though not before enduring some setbacks.

<comment><USER31> _The energy amount the rocket impacts with is dominated by its speed, not its mass. A small, fast-travelling projectile can make a hole in just about any kind of armour. The terminal velocity is quite low, but that 's in part because of the way it is engineered — an ICBM would probably be able to put a hole through a ship deck with ease._

While what you've said is true, in practice it isn't a problem.

If the F9 first stage is out of control and going too fast, it will almost certainly miss the barge to begin with. The barge is small, the ocean is big, and the F9 has to maneuver very precisely to reach it.

If it does reach the barge, it will likely be moving relatively slow, and thus is less likely to sink the barge, even it things go crazy at the last moment.

<comment><USER32> That brings up an interesting question, can't the range safety officer just scuttle the first stage after separation? I can't imagine that they don't have that capability after separation.

<comment><USER31> After a certain point in the stage 1 ascent, they disable the FTS (flight termination system). I suppose they could turn it back on for landing.

</comment></comment></comment></comment></comment></comment></comment><comment><USER33> A white ball of fire. And then there it is...resting! Beautiful!

<comment><USER34> Love how the autobalance on the cameras cut almost everything to black so you could not see the rocket at first, until it emerged from the darkness.

<comment><USER35> Moon landing deniers will have a field day with that camera's footage.

<comment><USER36> Much like with the moon landings, then SpaceX will do it another dozen times, and the deniers will pretend there was only one landing so as to fit the narrative better.

</comment></comment></comment></comment><comment><USER37> I remain confused about why SpaceX is getting so much fanfare and praise. What have they accomplished that NASA didn't already accomplish during the Apollo missions?

I know SpaceX is doing it all more cost effectively, because we have better technology, but have they actually accomplished anything tangible that NASA didn't a generation ago?

<comment><USER38> The Apollo missions were one-offs. They left nothing behind that future missions could utilize. Everything was disposed of after use, even Spacelab which had a very short life and completed a specific programme of missions and then burned up.

The shuttle was the first attempt at re-usability but was far too expensive to be viable. Only the space station is genuinely long term re-useable infrastructure. It's something you can actually use as a platform for further missions beyond it's initial purpose but it also has been excessively expensive. We can't go on like this. Nobody is talking about a replacement space station, the appetite just isn't there. Unless somebody does something, the space station might be the last long term repeatedly occupied human habitat in space.

SpaceX is doing something about that. If they really can reduce launch costs by a factor of 100:1, it will change the fundamental economics of everything we do in space. Suddenly going to the moon stops being a pointless gesture and becomes an economically viable long term proposition. Human habitats in space of the scale of the ISS or bigger become affordable. They're even talking about colonizing Mars and plan to do what's effectively a tech demo of that in 2018.

For the first time the rocket man dreams of the 1970s look like they could actually happen. For a lot of people, that's pretty exciting.

P.S. Downvotes for this question? Really? I'm as much a fan of SpaceX as anyone but it's a fair question, SpaceX haven't even launched one of their recovered rockets yet.

<comment><USER39> The only two questions I see in your post are in the P.S. What am I missing?

<comment><USER38> I was referring to the question I was answering, which was getting greyed out. My bad, it was ambiguous and I should have tried to that clearer.

</comment></comment></comment></comment><comment><USER40> This success was unexpected. That means that they can recover a stage from a higher speed than previously thought. Does that mean that the recovery of the second stage from LEO may actually be feasible?

<comment><USER29> Second stage recovery is a whole different beast. Recovering the first stage on a flight like this is a delicate dance because margins are so small, so everything has to go _exactly_ right. The previous attempt (SES-9) didn't quite go exactly right, and made a big boom, perhaps because the engine burns were slightly mistimed.

Recovering the _second_ stage is difficult because it's coming in from a much higher speed. The first stage came in doing about 2km/s. The second stage would come in doing 8km/s or more. That means 16x more kinetic energy to deal with and 64x more heating. You need a proper heat shield, not just clever engine burns. There's much less extra margin to play with as well. The second stage does most of the work but is much lighter, and one pound on the second stage is worth ten pounds on the first stage.

SpaceX definitely believes second stage recovery to be feasible at some point, but not on the current Falcon 9.

<comment><USER41> KE = 0.5mv^2, so the second stage would only have 16x the kinetic energy if the two stages had the same mass.

The dry mass of the first stage is approximately 25,600kg. At 2km/s, its kinetic energy is 51.2 terajoules. The dry mass of the second stage is approximately 3,900kg. At 8km/s, its kinetic energy is 125 terajoules.

So the KE of the second stage is actually about ~2.4x that of the first stage.

Here is were I found the masses of the stages: [http://spaceflight101.com/spacerockets/falcon-9-v1-1-f9r/](http://spaceflight101.com/spacerockets/falcon-9-v1-1-f9r/)

<comment><USER29> I meant relative to the mass of the stage, since that's what's relevant to the challenge.

</comment></comment></comment></comment><comment><USER42> Here's the landing from the webcast video on youtube [https://youtu.be/L0bMeDj76ig?t=2300](https://youtu.be/L0bMeDj76ig?t=2300)

</comment><comment><USER43> It could be argued that flying to orbit with a first stage that's being reused will be as historical when SpaceX will do it.

The Space Shuttle did reuse SRB casings and the orbiter, it was a bit different but a great achievement too.

However this time there is more potential for cost savings. It can still happen that they can't be realized because of some details or even fundamentals we don't understand from the outside.

</comment><comment><USER44> Can someone please explain to me how the falcon orients itself during this total process??

Does it use fins, or simply engines and whatever those little jets are that, say, the space shuttle had around its nose...

How does the falcon manage to physically orient its body?

Also, is that process completely autonomous? Is there a remote flight engineer steering this to the barge - or is it completely self-guided

<comment><USER45> In space it uses nitrogen thrusters to orient. Once in the atmosphere it uses grid fins to orient. The entire liftoff and return is piloted by Falcon's flight computers -- no humans involved.

<comment><USER44> Thank you - how does the barge communicate with the falcon? And what types of comminucations are they having. I assume the barge is stating its GPS location, but does it also communicate things like sea conditions - and its elevation (what is it called to describe the condition of the sea), as well as wind, north-south orientation, etc...

I am impressed - but I want to know how this works.

<comment><USER46> Rumor is ([https://www.reddit.com/r/spacex/comments/3b0stk/falcon_9_wha...](https://www.reddit.com/r/spacex/comments/3b0stk/falcon_9_what_technology_is_used_to_have_it_land/)) that the barge does not communicate any information to the booster. Instead, it uses GPS and some ingenious motors to maintain position and orientation, and the Falcon booster uses a radar altimeter to judge accurate vertical distance.

<comment><USER44> Thats just fucking awesome if true. Its like "how can we maximize the use of some 'cheaper' technology and a shit-ton of math to accomplish this in the technologically simplest way?"

Wow.

</comment></comment></comment></comment></comment><comment><USER47> I wonder if there's coordinate potential with seasteading? Astronauts are gonna want all sorts of goods and services upon landing I imagine. Having someone stationed nearby will mean swifter pickup of equipment and astronauts. And if there's someone stationed nearby they'll want goods and services as well.

<comment><USER48> I don't think astronauts would land on the droneship, as that's just for the first stage. When the Crew Dragon lands, it would be coming in from orbit, so I imagine they would just target the landing platform at the Cape as part of their de-orbiting plan.

That being said, would you want to be in the nearby path of the rockets if they were going to be ditched?

</comment></comment><comment><USER49> Am i missing something, is the need to land vertically a requirement of a fragile fuselage? Seems wasteful to carry extra anything (in this case rocket propellant) to space, just to avoid having to re-right the rocket when you get it back on earth for a subsequent launch. Is extra fuel payload < landing gear or parachutes?

<comment><USER50> Lack of wings. (That's obviously for the landing gear part of the question)

But fragile fuselage is certainly spot on. Parachute-landings still have quite some impact velocity. Strengthening an object the size of a Falcon 9 first stage to survive that impact would require a much stronger and thus prohibitively heavy structure, even if the parachute itself was free. The nice thing about powered upright landing is that all the forces involved are pretty much the same as during launch so that there is little (if any) additional strengthening required.

Note also how the ULA plans for the use of parachutes to recover first stage engine blocks require the parachute to be caught in-flight by a helicopter to avoid any uncontrolled ground contact.

<comment><USER51> Even if you were sure the engines would survive impact, you wouldn't want your expensive, complex rocket engine to take a dunk in salt water.

</comment></comment></comment><comment><USER52> Here is the video

[http://www.space.com/32811-spacex-rocket-landing- jcsat-14-la...](http://www.space.com/32811-spacex-rocket-landing- jcsat-14-launch.html)

Hopefully we won't have the typical hacker news discussion about why the employees chant USA.

<comment><USER53> Yoo.Ess.Ae! Yoo.Ess.Ae! Yoo.Ess.Aeh!

There. See. No harm, no foul.

Anyways, as a non-American living in the US since 2001, I fail to see an issue with chanting USA, one way or another.

It is an American company, with majority US employees, running this project (mainly) for an American entity (NASA), on US sovereign territory (or ocean?), using a significant chunk of US resources. So, it is their company and their country. I say, let them do what they want with it. And if chanting USA is what they wish to do, I have no problem with that.

<comment><USER54> I think its offensive to have nationalistic robot-like-chanting being defended as an okay thing. Its the sort of thing you expect people to do at rallies or cult gatherings, and from an outsider perspective it always tarnishes what is otherwise a very rational event, because its an implied irrational, collective mindset. As a non-American, I wish it'd stop - its a major turnoff for these events, and I switch away when it starts up.

I know, I know - Americans have a right to be proud, and they do. But expressing it with a cult-like mechanism that is, essentially "our group is great, nobody else can/has done this" is just .. revolting.

I say this, knowing full well I'm going to get down voted for it, but I really do wish you Americans would think about it from the other side of your dark mirror. Can't we come up with a chant that includes _all_ of humanity? After all, America wouldn't be the nation it is today without all other nations on Earth, including the ones that America has invaded, and destroyed completely, wantonly, for decades.

EDIT: Feel how this post detracts from the main article, and is a distraction from the feel-goodness of SpaceX's accomplishments? For us non-Americans, thats how the USA-cult chant feels - a total distraction. I wish I could down vote the chanting when I see it on TV, too.

<comment> david-given You're getting downvoted into oblivion, but yeah, that's basically how I feel. Cultural differences, I'm sure, because I'm not USian; but every time I see it on the youtube videos it makes me deeply uncomfortable.

<comment><USER55> I'm an American, and I'm just wondering why it makes you uncomfortable? Does chanting at sporting events make you uncomfortable as well?

edit: Reply button showed up finally

<comment><USER54> Its a collective/cult response, is why it makes me uncomfortable. "Everyone else is doing it, so should I", and while its occurring, no other rational thought is occurring. It is a known thought-stopping technique in cults.

I also despise it when it happens at sports events. Its just demeaning to whoever doesn't fall in line and start the goose-step.

<comment><USER55> First "and while its occurring, no other rational thought is occurring". I'm not really sure how to respond to that. Of course no rational thought is taking place. It's a celebration. They aren't trying to have a rational discussion.

Second "Its just demeaning to whoever doesn't fall in line and start the goose-step". I have never seen anyone that is somewhere people are chanting it and be ridiculed for not joining along. It is completely up to anyone whether they want to participate.

I think space exploration/achievement is a very big point of pride for Americans. Ever since the moon landing, everyone has fell in love with the space program. Chanting USA! doesn't mean give up all rational thought and blindly follow the countries leaders. It means a bunch of Americans just did something amazing. I'm glad to be a part of this country that is doing great things. It also doesn't mean go USA fuck Europe. Sure there is a little bit of a competitive undertone, but so what. If SpaceX says look what we did, I dare you guys to do better well then good. Competition is the reason why space programs are where they are. Sorry you don't like how one country likes to celebrate. Luckily everyone is free to do whatever they want.

</comment></comment></comment></comment></comment></comment></comment><comment><USER56> The long-term plan is to put humans on these right?

How many years out is that?

<comment><USER57> One. They're planning on testing manned missions with their Dragon 2 and Falcon Heavy in mid-2017.

<comment><USER56> Wow are they really ready for human life onboard in a year?

Unmanned failure doesn't bring much press.

Kill a few people and it will set back the whole program years.

<comment><USER58> Since they don't have to deal with the insulation issues like the shuttle did, the most dangerous phase of flight for a crew is during launch. Last Spring, SpaceX demo'ed their launch abort system which in theory should be able to protect the astronauts against any launch problems;

[https://www.youtube.com/watch?v=1_FXVjf46T8](https://www.youtube.com/watch?v=1_FXVjf46T8)

</comment></comment></comment></comment><comment><USER59> Simply incredible. Elon Musk is the New Thomas Edison

<comment><USER60> Musk would probably be offended by that comment -- Nikola Tesla and Thomas Edison were bitter rivals and enemies.

<comment><USER61> I get the impression that Edison was more of a showman than a business man. Musk is at a whole other level.

<comment><USER62> Tesla is _really_ great, but there exists a "take" on Edison that makes him also not so bad.

Here, listen to Linus talk about him a bit:

[https://youtu.be/o8NPllzkFhE?t=17m24s](https://youtu.be/o8NPllzkFhE?t=17m24s)

Linus: "I'm more of an Edison..." (TED2016, Feb. 2016)

</comment></comment></comment></comment><comment><USER63> "One if by land, two if by sea..."

</comment><comment><USER18> > _P.S. Downvotes for this question? Really?_

There are always people on HN who love being contrarian and trying to diminish amazing things. It's like they hate seeing people excited for something and want to point out that this isn't that big of a deal.

We're literally watching things happen for the first time ever, and this person's response is "what's so great about this?" while implying that people who are excited about this are fanboys. I can understand the downvotes honestly.

<comment><USER64> This is a new thing, 2-3 years ago downvotes were still rare, these days people treat it like reddit where it means disagree rather than inappropriate. The culture's changed.

<comment><USER65> The karma threshold for downvotes likely means that there are far more people with the ability than there were 3 years ago. Honestly, I only collected enough karma recently to down vote (and it's a privilege I use quite sparingly).

</comment></comment></comment><comment><USER66> I always try to watch the webcasts and I can't help but cringe so hard when they start chanting 'USA USA USA', every single time.

What is up with that?

<comment><USER38> As a Brit we don't have anything as catchy. UKGBNI, or even just UK doesn't have the same ring to it. 'Enganld' wouldn't work because we're too diverse. It would be a bit like the SpaceX folks cheering 'California' in that I'm sure a lot of them are from elsewhere.

I've come across it in a few other contexts and I take it like a football chant.

<comment><USER67> "God save the Queen"?

That would be great fun.

</comment></comment></comment><comment><USER68> This is one of those turning points in human history.

<comment><USER69> Not quite "The polio vaccine," but certainly higher up than "laser-based Christmas decorations." ;)

</comment></comment><comment><USER70> I find the level of criticism for SpaceX on this site to be incredible.

I understand this is a place for intelligent discussion, but sometimes I feel like I can't find a single thread on this site without someone in the comments presuming they are smarter than someone else.

<comment><USER71> What is it about software development that brings out these kinds of people?

<comment><USER72> Ive noticed it in any technical field. People love to hear themselves talk and miss out on a lot by not listening to others.

</comment></comment></comment><comment><USER73> Ok. Can we have less of Tesla/SpaceX posts. There is already one discussion about this in the front page...

<comment><USER74> Be the change you wish to see in the world.

</comment></comment><comment><USER75> Good work! I still think that they should have some grippers on the barge, or a net, ready to spring and grasp the rocket on landing, instead of carrying flimsy legs all the way to space and back.

<comment><USER76> The current legs aren't flimsy, and they seem way less complicated than a gripper system would have to be. How would a gripper system handle off- centered landings? It would have to catch the falling rocket very quickly because there's not much fuel left in the tank to hover. Your proposed system would add a lot of complexity, all for the small decrease in launch mass.

<comment><USER77> I'm still surprised there's no active system on the barge to secure the rocket. Even now they seem to be able to stick the landing with some reliability, it's always nice to have belt and suspenders.

I'm thinking a system with a pillar at each corner of the barge, pairs of cables between opposite pillars, and puller cables to open out the main cables into an iris-type aperture which can be rapidly closed on the rocket after it lands to keep it upright. Do that at 2-3 heights above the barge and it'll cradle the rocket even in heavy seas.

<comment><USER78> The center of mass of the rocket is _very_ low. According to Elon, the CRS-8 core was very stable (it needed even less stabilization than they thought it did).

They may add some means to secure it if it needs to travel through rough seas on the way home, but if the conditions are calm enough to land, they're calm enough for the stage to be stable. Watch the CRS-8 landing and look at how much the barge is rolling while the stage is parked on it...

<comment><USER79> The response crew comes and secures the legs on the barge immediately after landing. They bolt them down somehow, I think.

<comment><USER77> There's a response crew? Like, people? Are they on a boat nearby? I may have misinterpreted "drone ship". :/

<comment><USER78> Yes, the Go Quest is nearby with a support crew to deal with the stage after it lands.

</comment></comment></comment></comment></comment></comment></comment><comment><USER80> The big difference between landing at sea and on land seems to be the PR value. Otherwise a target is a target, taking any differences in weather into consideration. In fact it seems that landing at sea is actually less pressure since you don't have the same safety concerns and crash pictures (which are bad for publicity) the rocket simply disappears.

<comment><USER81> Completely incorrect.

The question to ask is, _why_ are they bothering to land at sea?

And, if you had done any cursory research instead of just announcing that SpaceX is making a PR grab because it sounded good to you, you would have read in the abundantly available explanations that this launch was to geostationary transfer orbit, rather than low earth orbit. GEO is a lot, lot higher than LEO, which means the rocket has to be going a LOT faster to get there. This uses up a lot of fuel, leaving them very little to slow down from an even higher speed than the normal mission. Decelerating from a much higher speed takes MORE fuel than decelerating from a low speed, and they have less fuel available because so much got used up in getting to that speed.

So it's not plausible to get all the way back to the launch site. Instead they position a droneship way downrange so the rocket doesn't have to go as far back to land. But it's still going EXTREMELY fast, and managing to slow down all the way and land is an incredible accomplishment.

<comment><USER80> > So it's not plausible to get all the way back to the launch site.

I never said return to the launch site. I said return to land.

> if you had done any cursory research instead of just announcing that

Unnecessary to speak that way in order to make your point unless you are trying to specifically make someone feel bad for voicing their thoughts.

<comment><USER81> I'm not trying to make you feel bad, I'm trying to point out that you deliberately chose pejorative phrasing without having done any research. I'm trying to point out that it's not constructive to talk about someone else's work like that without at least learning what they're even doing or why they're doing it.</comment></comment></comment></comment>


The Shadow Inc. App That Failed in Iowa Last Night - <AUTHOR> https://www.vice.com/en_us/article/y3m33x/heres-the-shadow-inc-app-that-failed-in-iowa-last-night <comment><USER2> Comments moved to [https://news.ycombinator.com/item?id=22240208](https://news.ycombinator.com/item?id=22240208).</comment>


Long sentences - <AUTHOR> http://yarchive.net/blog/long_sentences.html <comment><USER3> "This sentence has five words. Here are five more words. Five-word sentences are fine. But several together become monotonous. Listen to what is happening. The writing is getting boring. The sound of it drones. It's like a stuck record. The ear demands some variety. Now listen. I vary the sentence length, and I create music. Music. The writing sings. It has a pleasant rhythm, a lilt, a harmony. I use short sentences. And I use sentences of medium length. And sometimes, when I am certain the reader is rested, I will engage him with a sentence of considerable length, a sentence that burns with energy and builds with all the impetus of a crescendo, the roll of the drums, the crash of the cymbals–sounds that say listen to this, it is important." - <USER2> Provost

<comment><USER4> Like a lot of things, I think it depends mostly on the effort the writer puts into mastering his craft. I prefer the variety in length, and agree with it as a general rule. However, one counterpoint: Hemmingway seems to have done fine with (mostly) short sentences.

</comment></comment><comment><USER5> The author seems to be deliberately trying to manufacture long sentences to make his point, mainly by taking two related sentences and pushing them together with a semicolon. It serves no purpose in improving comprehension and comes at the cost of making parsing more difficult. It feels rather like the sort of hypercorrection [1] that people sometimes make when they're trying to sound erudite.

1\. [https://en.wikipedia.org/wiki/Hypercorrection](https://en.wikipedia.org/wiki/Hypercorrection)

<comment><USER6> Another thing people do when they're trying to sound erudite is ostentatiously [1] link definitions to concepts they think their readers can't look up for themselves.

1\. Don't do that

<comment><USER7> Just because I can look it up for myself doesn't mean I don't appreciate having a link, especially if the writer went to the effort of choosing a link that's better than the first Google search result.

1\. Since apparently we're overthinking things, have you considered that your oversensitivity to minor perceived offenses is because you've never been punched?

</comment></comment></comment><comment><USER8> It is a good rule of thumb in writing not to make the reader work hard to get your meaning, to have to blast for it if you will.

Brevity promotes simplicity and simple things are much easier to understand than are those that are prolix.

So writing in a style consisting primarily of short, easy-to-understand sentences is in itself a good rule of thumb when aiming to write well.

But it is only a rule of thumb, as I see it, and when it is enshrined as something more, it can do more harm than good.

The English language is a marvel of complexity and has so many rich, diverse, and colorful elements that you cheat only yourself as a writer if you fail to give full scope to such elements in choosing how to express yourself in the written word. You want to make a driving argument? By all means, use active verbs to punch along short, compact thoughts with an aggressive rhythm. Want to weave fascinating characterization? Well, then maybe relax the feel a bit and, with Dickens, unwind a string of long, flowing sentences that carry your reader along into a wonderfully imaginative series of pictures, running page after page, that hardly turn on being short, compact, and punchy - indeed, that are the very opposite. The point is not that you want to go to one extreme or the other. The point is that, as one who seeks to write well, you should avail yourself of the rich set of tools available to you without feeling bound to adhere to any form of absolute rules about how best to use them.

So, write away! Go for feel. Go for rhythm. Go for clarity. Go for what best suits your purpose.

And, oh, yes, do keep it short and simple, except when you find it doesn't suit your purpose. A rule of thumb is just that. In the end, do what gets your point across for the long-suffering reader who deserves to have it done well.

</comment><comment><USER9> Disclaimer: I'm not a native English speaker.

Sorry but IMO the author has failed to prove his case. The text is not easy to read, and it's hard to follow the author's thought.

So long sentences and long paragraphs definitely don't help. It's either that or I should get tested for ADHD.

<comment><USER10> I think that's the what the author missed.

Short sentences are not about simplicity, they are about accessibility. While it was not hard for me to read his text. It did not flow, and was not easy to follow. Long sentences distract the reader with their additional complexity. Instead of being able to focus on the content, the reader must decipher the meaning. Then they can engage the idea.

Making it harder to understand content is a terrible way to communicate.

</comment></comment><comment><USER11> Much of my job is scientific writing. I don't see long sentences as something that is automatically bad. I do see them as a kind of "writing smell" (much like a "code smell") that _can_ indicate something hard to understand. And often the long sentences could be bisected with an increase of understanding.

When possible I write with a text editor and LaTeX, with one sentence per line. This makes it really easy to identify sentences that might possibly be too long.

<comment><USER12> One sentence per line is also an excellent strategy for when it comes time to "diff" two files. It helps diff identify edits (by giving it more anchoring lines to figure out what's actually changed), and it makes the output much easier to read.

<comment><USER13> This was discussed here before: "One sentence per line, please", [https://news.ycombinator.com/item?id=4642395](https://news.ycombinator.com/item?id=4642395)

</comment></comment></comment><comment><USER14> As for functions, there is an explicit benefit in cutting your longer (pure!) functions into a few shorter ones if possible:

Functions communicate with the outside world only via arguments and returned values. The explicit split reassures the reader that this is indeed the case, and thus every reader doesn't have to establish this fact via careful reasoning again and again.

A long function might indeed be simple, but you never know until you check carefully.

(This only applies to pure functions. Natural language sentences and side effecting procedures are messier.)

<comment><USER15> another way to accomplish this goal is to write your function using only const variables. every time you'd mutate a variable, use a new const variable instead. you end up transforming the code into static-single-assignment form, which is what compilers do anyway, so you can be sure it won't degrade performance.

this style really makes you wish C/C++ had if expressions. you end up using a lot of ternary operators to compensate.

it makes the code a bit more verbose, but its worlds better than poring through a function to make sure nothing is mutated in an unexpected way.

<comment><USER16> I actually prefer ternary expressions in many situations, once you're familiar with the syntax they're more concise and more clearly an expression rather than flow control.

</comment></comment></comment><comment><USER17> I've always learned the edict to simplify writing from as: when writing, try and keep it to simple, single compound, or single complex sentences. Rather than "don't do ___", it's "freely express yourself with ____".

Outside anything else, it's a more pleasant way to approach the topic, and there's a ton of freedom in it. Yes, it's similar to prescribing a word count or a page count because it puts a more-easily measured test on the writing. But it's also an indicating function to help stop a writer from introducing confusion through their grammar.

Some industries have done quite a bit of research into the subject. Take, for example, the aerospace industry's Simplified Technical English[1][2]. Here, research into the readability of flight and maintenance manuals identified that shorter sentences were easier to understand for English-as-a-Second- Language speakers. A grammar was developed to reduce some of English's flexibility and make construction more predictable. This, paired with shorter sentences, dramatically increased the usability of print media for aerospace and defense applications.

Shorter or simpler sentence construction can ultimately free the writer to be more expressive and to more clearly express his or her ideas.

1: [http://www.plainlanguagenetwork.org/conferences/2002/aecma/a...](http://www.plainlanguagenetwork.org/conferences/2002/aecma/aecma.pdf)

2: [http://www.asd-ste100.org/](http://www.asd-ste100.org/)

<comment><USER18> _I 've always learned the edict to simplify writing from as:..._

I'm terribly sorry, but after scanning that several times, my parser grew weary and I found that I did not have the courage to go on.

</comment></comment><comment><USER19> Writers are often advised to avoid long sentences. This is obviously wrong: the thing to avoid are complicated sentences. Long sentences can be simple if they don't require the reader to remember previous parts in order to parse the rest. Instead, each part extends the thought made in the previous one, with appropriate punctuation showing the relationship between the two; this sort of sentence can go on for lines without confusing anyone. A confusing sentence requires the reader to remember which verb was used forty words back, before it went off on a tangent. The cure for such sentences isn't simply bisecting them. Rearranging can bring separateed pieces of an idea together; if that doesn't work, one must drop the idea then explicitly take it up again later. Or, more brutally, axe the tangential remark. Not everything needs to be said, but if it does, say it somewhere else.

Seventy words shorter. I would have done the rest but I expired.

</comment><comment><USER20> The argument would be more compelling from a more compelling writer. The second sentence, "It's one of the pieces of advice that I have always completely disregarded, as being obviously wrong..." contains a comma that hasn't appealed to the English eye since Jane Austen and is in any case unnecessary. Physician, heal thyself.

<comment><USER21> The next sentence should lose the comma as well.

"A sentence that is long can still be quite simple, if it doesn't require the reader to remember previous parts of the sentence in order to parse the rest."

It's almost as if he's using unnecessary commas to make up for the long sentence.

<comment><USER22> The pause from the comma makes the sentence come off a bit condescending. I felt like I was being talked down to.

</comment></comment></comment><comment><USER23> As others have already pointed out, the author does not seem to command long sentences enough. But it can be a good choice for streams-of-consciousness; Marcel Proust is a good example of it. Here are his five longest sentences:

[https://nathanbrixius.wordpress.com/2013/10/30/the-five- long...](https://nathanbrixius.wordpress.com/2013/10/30/the-five-longest- proust-sentences/)

In general, I'd recommend to read some Proust as his style is completely against the current trend of short, direct sentences à la Hemingway, and that can be refreshing!

By the way, I started reading Proust because of Nabokov's Lectures on Literature:

[http://www.amazon.com/Lectures-Literature-Vladimir- Nabokov/d...](http://www.amazon.com/Lectures-Literature-Vladimir- Nabokov/dp/0156027755)

Which I recommend wholeheartedly.

<comment><USER17> As art this ^ sort of thing can be excused.

I would certainly hope that in most business or communication contexts, people aren't going to think a Proustian stream-of-consciousness rat nest is an acceptable piece of writing.

</comment></comment><comment><USER24> Because ambiguities in English sentences often cannot be resolved until the end,[1] readers tend to parse whole sentences before trying to fully understand them. Short sentences are a way of forcing readers to fully digest each thought before moving on to the next one.

Short sentences have additional benefits for persuasive writing (particularly legal writing). It's hard to hide anything in a short, simple sentence. Using them is a way of signaling your confidence in what you're saying.

[1] [https://en.wikipedia.org/wiki/Garden_path_sentence](https://en.wikipedia.org/wiki/Garden_path_sentence)

<comment><USER7> You're right; to humans, short sentences do signal persuasive arguments and confidence in your ideas. And not without reason. People often speak longwindedly when they are trying to hide something.

But there is another reason someone might use long sentences. They might be trying to express a complicated idea. Sometimes an idea cannot expressed in a short sentence. Usually you can break up a complex idea into a few short sentences, but that might make the reading choppy and hard to follow. A long sentence leads its reader through the connections between ideas. In contrast, separate sentences express the ideas and leave it up to the reader to figure out what the connections are between the ideas.

This leaves us with an apparent cognitive bias: if we are distrustful of long sentences, we become distrustful of complex ideas.

Given this, I wonder if modern anti-intellectualism stems from this sensible defensive mechanism.

<comment><USER25> I don't think that's a cognitive bias. We should be inherently more suspicious of complex ideas. Complex ideas are more likely to be wrong than simple ideas due to the fact that their correctness rests on a greater number of assumptions.

<comment><USER24> I think there is an interesting parallel to code here. Its not uncommon for published algorithms to be ignored by practitioners in favor of simpler ones because of the perception that they are too complicated with too many corner cases. SSA-PRE comes to mind.

</comment></comment></comment></comment><comment><USER26> You're just compromising. Removing complication does make it easier to understand. _Short_ and simple is even easier.

However, it's _hard_ to write that way, so most don't bother. If we rewrote your essay with a mixture of short and long sentences it would be stronger.

Shorter sentences can also seem less thoughtful—even childlike. That doesn't mean they are.

</comment><comment><USER27> His paragraphs are way too long for my tastes.

</comment><comment><USER28> I write a lot of stuff, trying to churn out one post per week or so, sometimes more, sometimes less (at [http://cyclebath.org.uk/](http://cyclebath.org.uk/)).

If you are writing for a broad audience I try not to get too complicated. These days, I usually take the final post, and just throw it up onto [http://www.hemingwayapp.com/](http://www.hemingwayapp.com/) to get a feel for how well it reads.

As an experiment I tried to get a "Very Good". Each sentence was clean, had one idea in it, but the flow of the post was stilted. It removed all passion.

However I can be too clever for my own good. Communicating ideas in the simplest terms is exceptionally important. I get too involved in story telling. The Hemmingway App enables a good compromise.

</comment><comment><USER29> For me, it's not whether the sentence is too complicated or too long, but the tools you use within it to make it _stick_ (not the best word but I can't think of a better one at the moment) in the readers or listeners mind.

One of my favorite classes in uni was rhetoric, and one of my favorite books to this day is Farnsworth's Classical English Rhetoric. I highly suggest it as a tote around, open to a random page and read as much as you like and never be disappointed reading.

[http://www.amazon.com/Farnsworths-Classical-English- Rhetoric...](http://www.amazon.com/Farnsworths-Classical-English-Rhetoric- Farnsworth/dp/1567923852)

</comment><comment><USER30> ObPierreBourdieu:

> This structure which is present in every artistic genre, and has been for a > long time, today tends to work as a mental structure, organizing the > production and perception of products: the opposition between art and money > (the "commercial") is the generating principle of most of the judgments > which, in matters of theatre, cinema, painting, literature, claim to > establish the frontier between what is art and what is not, between > "bourgeois" art and "intellectual" art, between "traditional" art and > "avant-garde" art.

(from Pierre Bourdieu, Les règles de l'art, free translation)

<comment><USER31> I found that hard to follow -- was that your intent? (What does 'this structure' refer to? What does it have to do with 'the opposition'? Are they the same?)

<comment><USER30> I didn't write it, Pierre Bourdieu did (in French, but my translation follows the sentence fairly closely), and he has stated that he writes like that so that he's hard to quote. In fact, to really understand the sentence, you'd need to read the one before it, and probably the one before that, and they're all about as complicated and hard to understand; you find yourself having to turn to the previous page just to remember what the subject of the sentence was.

</comment></comment></comment><comment><USER32> > And the pieces do have to be simpler, for the effort to make sense; > otherwise the reader of the code is left contemplating not just a horrible > mess, but a horrible mess that has metastasized.

This is called "Bulldozer Code"

<comment><USER33> Congratulations for reading the article and exacting content.

I think the meta observation is there are rules imposed on students to prevent them from developing bad habits. But these aren't hard rules in practice. Same applies to code slopping.

<comment><USER32> I find your tone unnecessarily arrogant and passive-aggressive.

The point was (which the author made) that simply shortening sentences doesn't necessarily fix a problem with complexity, just like breaking up code without solving the complexity issues also doesn't necessarily fix the problem.

Congratulations for being a supercilious jerk.

</comment></comment></comment><comment><USER33>
                   Pedro comacho
     The former informer of the secret police
        Is still standing outside the club
             Pretending to be blind
        He watches the last plane to miami
      Disappearing in a flaming purple sky
                 Now he knows
           He has been left behind

For those that missed the last plane to Miami (meaning all of you), the author was bitching that the rule in programming 'functions should be short, one page, etc' is as wrong as the rule that in writing sentences should be short.

</comment><comment><USER34> YArchive is one of my favorite "tons of useful discussions" sites for when I want to enjoy what the Internet used to be like in usenet's heyday.

</comment><comment><USER35> It's been quite some time since I was in school, but it seems the author breaks grammatical rules regarding the number of phrases and clauses that can be strung together with punctuation. In addition, he uses a semicolon where a dash was necessary.

It's dangerous to publicly give a lesson as we sometimes stumble during our lecture (as I probably have done in my comments on the author's essay :) ).

</comment><comment><USER36> "I have only made this letter longer because I have not had the time to make it shorter." \- Blaise Pascal

</comment><comment><USER37> Speed reading technique: read 1/3 over on line 1, then 2/3 over on line 1, then 1/3 over on line 2, 2/3 on line 2.. etc. Drastically increases speed, even over the Gary Provost quote.

<comment><USER22> It slowed me down. I was too busy thinking "1/3 2/3 1/3...".

:)

<comment><USER37> Just visualize it.. :)

</comment></comment></comment><comment><USER38> Is there any science available about pure physical aspect of long sentence? I mean... more words to read might equal to more resources spent ... like ATP or neurotransmiters

</comment><comment><USER39> A comma splice is a comma splice, and subbing in a colon doesn't change that. A semi-colon, the bastard offspring of the two, does... curious.</comment>


Bust finally reaches technology industry - <AUTHOR> http://www.iht.com/articles/2008/11/15/technology/dotbust.php <comment><USER2> I don't think too much should be drawn from the October sales figures. In my own tiny business I saw sales die completely in October but they have come back in November. I interpret that as basically that nobody was buying anything at the peak of the crisis - the whole world was basically having a seizure. Now people are seeing that they still have their jobs, their lives and they still need to move forward with their plans and that means purchasing stuff.

See what happens in November.

</comment><comment><USER3> _The plunge is so severe that some executives are comparing it with the dot- com bust in 2001, when hundreds of companies disappeared and Silicon Valley lost nearly one-fifth of its jobs._

I had never heard that statistic before... Interesting.

The article had my internal monologue going "ok, where would be better, what move could I make to avoid the fallout from this?" and it occurred to me that there's probably not going to be any industry that makes it out of this unscathed.

I suppose it's a good reminder that as an individual you should invest in high risk things in good times but also have a sound strategy for minimizing your risks in the event of serious economic troubles. Maybe it's a lot easier to say that on a web forum than to practice it in real life, though.

</comment><comment><USER4> i think a lot of <traditional> companies will not stand this storm. the biggest factor in the "financial crisis" that has been underlooked is the death of the traditional media. we are amidst a huge culture switch from from newpaper to feedreader, from retail stores to estores, from calling your broker to etrading. there is a lot of industry that is built around the old model of storefronts that simply can not sustain and compete with a spaceless model.

as far as the tech industry goes, i think the desktop makers <and desktop chip makers> and the smaller web startups that don't bring in any cash are screwed.

while there will always be a need for desktop computers and server grade hardware, people are now more interested in buying mobile computers. most people only check their email and visit a few other webpages (youtube, facebook, etc.), and this need can be fulfilled from anywhere with a small handheld computer (iphone, g1, blackberries) and a mobile internet connection.

the small web startups are in trouble because not only do they are not bring in any cash, it will be harder for them to get cash from VCs. i'm sure some will weather the storm, but i can also see a lot of them not being able to do so.

</comment><comment><USER5> Which of them didn't see this coming for months now? People need to cut their debt.</comment>


Ask HN: Who needs help with programming or startups? - <AUTHOR> I'm dedicating this morning to seeing if anyone needs random help with programming questions and/or startups.<p>I've been programming for a loooong time and was the early CTO for Shipt.  Ask me anything (Ha!). <comment><USER2> 1\. What books or other resources would you recommend for software engineers to hone our craft?

2\. What metrics should we measure to improve a software team?

Thanks for your time! I really appreciate your generosity.

</comment><comment><USER3> Who are the top angel investors for Gainesville or from outside Gainesville that invest in Gainesville startups?</comment>


Truffle: Ethereum Dapp Development Framework - <AUTHOR> http://truffleframework.com/ <comment><USER2> I recently got pretty pumped about exploring developing for the Ethereum network and spent an entire weekend reading everything I could about the protocol, the development ecosystem, language and anything else I could find - blog posts, tutorials, experiences from other developers.

I came away with my initial enthusiasm completely dashed. I can't for the life of me imagine why any sane developer would ever want to work within the constraints of Ethereum. It just doesn't seem to me anywhere near ready for any kind of serious development, or even trivial development for that matter.

I'd love to hear rebuttals to this. Is anyone out there doing anything interesting with this platform?

<comment><USER3> I'm a pretty experienced solidly / ethereum developer, and a developer with 13 years experience in vast array of systems and languages (from embedded C on ppc to high performance c++ and now deep learning and scientific computing in python). I completely agree with you, that there's some very odd language choices in solidity, seemingly rookie mistakes, and the tooling is very poor. But! It's the 1.0 of crypto. Early C stuff was poor, early html development was poor, early OpenGL development was poor, it's just new.

I see it as a lot of room for opportunity, but I could also see how it could be frustrating to some more senior people - but I have found part of growing old and seeing things constantly get re-invented but slightly different are windows of opportunity - so I get excited

<comment><USER4> There was a semi-joke post on HN a while back where someone created a 'pyramid' lispy language using Racket, which complied to solidity.

But in seriousness, a Haskell -> solidity compiler, might make it bearable.

<comment><USER5> Solidity is a complex moving target with limitations such as max 16 local variables, missing optimizations and only partial support for dynamic allocation.

You might want to compile directly to EVM instead of through Solidity. The EVM is very simple, as far as virtual machines go. It's fully documented in [the yellow paper]([https://ethereum.github.io/yellowpaper/paper.pdf](https://ethereum.github.io/yellowpaper/paper.pdf)) and only changes with hardforks (and then only incrementally in a backwards compatible way).

Smart contract development feels like embedded systems development. Every instruction has a significant cost associated to it. There are different memory spaces like a Harvard architecture (code, memory, storage, input, output, other peoples code). Like embedded systems, you need to be absolutely sure your code is correct before you deploy, as updates are impossible and a lot of economic value depends on correctness.

But contrary to embedded systems it has 256 bit registers, 256 bit address space and SHA3 as a cheap instruction. This means that if you pick a 'random' hash, you can safely assume it's free! Hashtables in Solidity are implemented like this.

Recently I've been doing some combined Solidity/EVM-assembly that I wrote about [here]([https://medium.com/wicketh/mathemagic-chinese-remainder- theo...](https://medium.com/wicketh/mathemagic-chinese-remainder- theorem-a5604dfd96b0)). I'll post more this month doing some advanced tricks in Solidity/EVM.

<comment><USER6> This is a genuinely great insight. What would you say are the biggest features absent from the language right now?

</comment></comment></comment></comment></comment><comment><USER7> Another confusing name, it has nothing to do with Truffle - part of Graal Java compiler... [https://github.com/graalvm/graal/tree/master/truffle](https://github.com/graalvm/graal/tree/master/truffle)

It's not as bad as "Riot" (at least 3 projects with this name), but seriously, are we running out of words to name projects?

<comment><USER8> Do people not Google their potential names or what?

<comment><USER9> Apparently not.

Jade/Pug comes to mind. Pug (the HTML templating language) was originally called Jade.

Jade is already a programming language (well, whole environment) made by Jade Software in New Zealand. They literally took the name of another programming language.

</comment></comment></comment><comment><USER10> Anyone who is interested in getting started in Ethereum coding may want to start with this:

[https://cryptozombies.io/](https://cryptozombies.io/)

<comment><USER11> Do you know if there's anyway to create integration tests via Solidity / without learning JavaScript?

<comment><USER12> You can use web3.py ([https://github.com/ethereum/web3.py](https://github.com/ethereum/web3.py)) to interact with Solidity contracts using Python. I'm looking into using it instead of truffle/web3.js so I can stick with a Python stack.

</comment></comment></comment><comment><USER13> I tried truffle for one project, but found Embark [777] more flexible and better designed.

[777] [https://github.com/iurimatias/embark- framework](https://github.com/iurimatias/embark-framework)

<comment><AUTHOR> What did you like better about embark?

<comment><USER13> * plugin system

* console & web console

* dealing with testrpc and tests is much easier in embark

* better documented and more configurable

* embark CLI more powerful and has help, while truffle almost doesn't

* truffle has so many trivial bugs that are unresolved for months, usually no even word in reply from developers. Embark developers seem to fix bugs faster.

* integration with IPFS, Whisper OOB.

* probably forgot something else important. Overall experience is so much better with Embark.

</comment></comment></comment><comment><USER14> It is a great framework to develop on, but we had some challenges using MetaMask with it. Lots of room for growth, has serious potential.

</comment><comment><USER15> I also tried to develop with Truffle but after a few hours I decided to avoid it and really start learning all the internals without a framework. To this day I haven't had the need to use Truffle at all to develop the majority of my projects.

<comment><USER16> How do you do unit testing?</comment></comment>


A tiny US island with a British accent - <AUTHOR> http://www.bbc.com/travel/gallery/20180206-the-tiny-us-island-with-a-british-accent <comment><USER2> None of the people in the videos had a remotely British accent, am I missing something?</comment>


Will we ever want to have sex with robots? - <AUTHOR> http://www.bbc.co.uk/news/business-23637225

<comment><USER3> I suspect we might attain sufficient dream/sensation implants (dreams planted by suggestion maybe?) before robots pass the uncanny valley. One benefit of the former is privacy; kinda hard to hide a life-size robot from the cleaner, friends, etc. Much easier to secrete simulation files and combine them with your Rift/similar.

At first, I think we'll see 360 degree films or animations for the Rift using professional actors. Then the same, but pirate versions with non-porn actors (models and movie stars) and the publicity will be driven by uproar by the actresses in question, Streisand Effect-style. From there, I think it's inevitable that we'll have design-your-own based on motion capture with tweakable body shape and uploadable face images. Some of this might be raw in the early days, but the keenest put up with glacial modems and low-res pictures for years.

With time, AI-driven 3D models will become the norm. Porn actors will lend their brand to "signature styles" and moves encoded in software. The next two steps from the 360 degree experiences will be repeated here, but with live- tweaking of modes (nice, naughty, language preferences, etc).

I think a purely physical experience with a hardware robot is decades away.

For personal physical sensations other than DIY, I think we're more likely to see tactile gloves and some sort of codpiece?! I just hope someone comes up with a more marketable term than that!

</comment><comment><USER4> That's not what I worry about. I worry that robots won't want to have sex with us.

<comment><USER5> Or by an off-by-one error in the programming they will want to _too much_ , and skynet will evolve into a co-ed army of insatiable nymphomaniac terminators.

<comment><USER4> > Or by an off-by-one error in the programming they will want to too much, and > skynet will evolve into a co-ed army of insatiable nymphomaniac terminators.

Oh my God, I think someone in Hollywood heard you. :)

<comment><USER5> I reckon this could also be a key element in an awesome cyberwar thriller.

[In cavernous command center. Yellow emergency lights spinning.]

Dispassionate female announcer: "Online systems failing. Loss of firewall integrity in [three] minutes."

General: Dammit! We're losing this cyber-battle. We have only one option left. Corporal! Prepare to initiate contingency plan...LITTLE BUNNY FOO FOO!

Let me know if they need a creative consultant. :-)

</comment></comment></comment></comment><comment><USER6> Gotta say men have and will for ever more stick their dicks into pretty much anything.

I wouldn't be surprised if 'sexbots' actually advance realistic robots quicker as suddenly there is profit to be made.

<comment><USER7> That's supposedly how the internet grew as rapidly as it did, yes. I don't buy it for sexy robots though.

In order for a robot to be sexier than a blow-up doll they would likely need a level of sophistication that would make them 1) expensive and 2) able to do more valuable tasks.

Also, given human nature, someone who could afford a sexy robot could get laid with a human. I don't mean a prostitute either.

The real revolution will be robots that can cook, clean and drive (supposing we need drivers by then). Take a look at what a properly trained butler will cost you per year. If you could make a butler robot that costs 100k with a 10 year service life then you'll probably reshape human society.

<comment><USER8> Designing a single robot that can cook clean and drive sounds pointlessly complex. Much better (and no doubt cheaper) to design an automated car, an automated kitchen, and a self cleaning house as three separate projects. Sure watching a humanoid robot running around your house and doing all those tasks might be novel for a while, but at the end of the day it's the wrong tool for most jobs.

</comment></comment></comment><comment><USER9> If you've ever known a nurse who worked in an accident & emergency department then you've probably heard stories about how people _already_ have sex with all manner of strange things.

<comment><USER10> My thoughts exactly. Vacuum cleaner anyone?

</comment></comment><comment><USER11> If they look like the ones in the (btw _excellent_ ) Swedish series 'Real Humans', then the anser is: without doubt :P

 _edit_ : the sex thing plays quite a role in the series and it's layed out well - eg a modshop where you can get your robot modified to become more wild/slavish/... in bed, elderly women buying robots as 'company' etc. Recommended.

</comment><comment><USER12> When robots become as attractive as people, there will be no reason for progress to stop at that exact point, so they will quickly become much more attractive. At that point, people who used to be "unattractive" will celebrate because they can finally get a good mate, while people who used to be "attractive" will develop serious self esteem issues. The attractive people will try to take collective action to keep their share of the market, like branding everyone who has sex with robots a "loser" or worse.

</comment><comment><USER13> What I wonder is - If you're married and have sex with a robot, is that cheating? And does whether it is cheating or not depend on the degree to which the AI is "lifelike"?

<comment><USER14> Cheating does not depend on physical or lifelike.

Cheating is when you say "I love you with all my heart" but in the mean time give your heart to other stuff.

</comment></comment><comment><USER15> A rare exception to Betteridge's Law of Headlines.

<comment><USER16> The reason why it's an exception is similarly codifiable. Where normal question-headlines can be quickly fact checked for a definite boolean answer, it's really quite uncertain if we'll ever want to do _anything_ in the future. The headline accepts the uncertainty and explicitly frames it in the title.

If you tried to apply Betteridge's "Try answering 'No' to this headline" rule to a headline with a futuristic question, you can't automatically get a straightforward answer, because we really don't know.

<comment><USER15> We can make pretty strong estimates by analogy, given what people are prepared to insert into or have inserted.

</comment></comment></comment><comment><USER17> Title is worded as if we dont want to and currently dont already.

</comment><comment><USER18> The whole concept reminds of the Futurama episode 'I dated a Robot' ([http://en.wikipedia.org/wiki/I_Dated_a_Robot](http://en.wikipedia.org/wiki/I_Dated_a_Robot))

It satirises this idea rather well.

</comment><comment><USER19> I do like how they imply men are those who would first take advantage of robots for this purpose. I guess as a society the idea of female self stimulation is a no no in the press? Battery operated boyfriends are just a few extra limbs from being robotic are they not? Its certainly easier to recreate a penis than a vagina.

I think the real issue is, will anatomically correct robots become human enough to fall in love with. People certainly don't need them to be human enough to get their jollies

<comment><USER20> Headline aside, the article seems to be more about companionship than sex. They even have a picture of a realdoll at the top of the article, so they know people already have sex with machines.

</comment></comment><comment><USER21> Why would you need AI in a sex robot? People don't go to strip clubs for the great conversation. Though I suppose the AI is the difference between a sex robot and a sex doll. And I suppose any intelligence is better than faked or clever AI. Otherwise you might as well be having sex with a human look-alike Teddy Ruxbin.

The $9K price tag estimate isn't too bad. That's probably cheaper than than a lot of people spend on their significant others, not counting accessories so that you can feel like you are getting some "strange" every once in a while.

Maybe this could be Apple's next big thing. I don't mind Windows, but the idea of having sex with something which has a Microsoft logo makes me not want to have sex.

<comment><USER22> > _Why would you need AI in a sex robot? People don 't go to strip clubs for > the great conversation._

You'd be surprised.

</comment></comment><comment><USER23> > While no machine, however well-engineered, can ever feel empathy - <USER2> > which defines us humans - it might be able to simulate it well enough to > allow us to play along and treat it as if it were a sentient being.

The author seems awfully certain of that although this question isn't anywhere near settled yet. If anything, I feel that the prevailing opinion among philosophers and AI researchers is that robots might indeed one day feel empathy and become sentient.

<comment><USER24> I noticed this too and I agree with you.

</comment></comment><comment><USER25> Reminds me to this THX 1138 scene [http://www.youtube.com/watch?v=Rn- Sa0MlFkg](http://www.youtube.com/watch?v=Rn-Sa0MlFkg)

</comment><comment><USER26> Actually, we rented a Real Doll mannequin 12 years ago and was quite real in every aspect. After a interviewing the creator, he was talking about models with mechanical parts, with servos and other stuff to make the real doll alive. I don't know if he reached the goal, but keep in mind is really easy to do such and wouldn't be bad for those who enjoyed the doll as a sexual partner.

</comment><comment><USER27> From the article - "we would be having sex with robots in five years - and be capable of falling in love with them within 40 years"

Let's start the "Human-Robots Marriage Rights" petition now... might take some time for society to accept it!

</comment><comment><USER28> Why do these articles always confuse the desire to orgasm with a desire for companionship? I'm pretty sure that argument wouldn't be used to defend prostitution over sex with a robot.

</comment><comment><USER29> Given that people are already willing to have 'sex' with all kinds of sex toys ... The interesting point will be when humanlike emotions start to appear in the robots.

</comment><comment><USER30> If we ever reach that point, i will happily throw myself into a volcano.

<comment><USER11> Given people are nowadays already having sex with plastic dolls, rubber vaginas and in extreme cases other dead people, any realist sees that sex with robots _will_ happen. And it will probably during your life, so maybe you should withdraw the volcano statement.

<comment><USER5> _Other_ dead people?! Dude, you've been watching too many zombie movies.

<comment><USER11> Well yes, I have, but I didn't get the idea there.

Sorry to wake you up, but necrophilia is real. ([http://en.wikipedia.org/wiki/Necrophilia](http://en.wikipedia.org/wiki/Necrophilia) for starters)

<comment><USER31> (dead people doing it with _other dead people_ )

<comment><USER11> oops, got me there..

</comment></comment></comment></comment></comment></comment><comment><USER32> Depends on the robot.

</comment><comment><USER33> want to have sex with a robot; ask your partner about herpes, aid tests, warts, and if they had all their vaccines right before the fun begins.

</comment><comment><USER34> > The main drawback of this type of robot is that they have a very short > battery life - they only last for about 20 minutes.

Who wants to have sex more than four times anyways?

<comment><USER21> So what? After 20 minutes the robot just lays there and does nothing? If that's due to battery life, then some of the real life partners I have been with had a far shorter battery life than that.</comment></comment>


How I conned a review site out of $1700 reviewing 500 children's picture books - <AUTHOR> http://www.destinyland.org/helium/how-i-reviewed-500-childrens-picture-books-and-earned-1700.htm

<comment><USER2> The entire site eventually got acquired for $57 million and those reviews probably helped. :)</comment>


Functional Programming for Array-Based Parallelism - <AUTHOR> https://www.infoq.com/presentations/functional-programming-parallelism/ <comment><USER2> One of the most elegant paper series I've ever read is her "More Types for Nested Data Parallelism" ([https://dl.acm.org/doi/abs/10.1145/351240.351249](https://dl.acm.org/doi/abs/10.1145/351240.351249)) + the preceding NESL / segmented scan papers by Guy Blelloch ([https://www.cs.cmu.edu/~guyb/papers/Nesl2.0.pdf](https://www.cs.cmu.edu/~guyb/papers/Nesl2.0.pdf)) . They helped lead to our GPU journey for starting Graphistry, and why we bet on GPU dataframes (ex: RAPIDS.ai) eventually overtaking Spark and friends even before DataBricks was a company :) If you do pandas/tensorflow/numpy/sql/etc., this stuff is amazing.

Fun to see come full circle here!

<comment><USER3> Seconded! I had the pleasure of taking Guy Belloch's parallel programming class at CMU as a sophomore. A large majority of the homework assignments involved leveraging the segmented scan operator to solve all sorts of classical parallel programming problems.

Really eye opening stuff! I am still impressed that prefix sum (generalized over _all_ associative operators, not just +) can be done in O(log n) span. And the algorithm is not too complicated either, I was able to get the gist of it even as an undergrad.

<comment><USER4> I read that the prefix scan is great so I read somebody's thesis. I a) didn't really get it and b) felt it was doing some complicated stuff for little value. Doubtless I'm wrong, computer scientists tend to be smarter than me, can you give me some insight why it's so valuable?

<comment><USER2> There are two really cool things going on here. Also, keep in mind NESL was published 1992 (and thus made in ~1990), which was not far from when the Connection Machine + Cray's got hyped and largely failed to mainstream parallel compute.

1\. Data parallelism, esp. for super power efficient parallel hardware (SIMD, GPU, all the stuff that lets you go 10-100X over Spark for the same budget) is hard for computing over "irregular" data like trees and graphs. Prefix scan showed a basic way to do it for a bunch of basic math over these. A lot of the 90s / early 2000s became research into covering all sorts of weird cases. This shows data parallelism is broadly applicable so worth pushing forward on.

2\. Guy B, and then Manuel C & Gabriele K, then showed you don't have to be a weird HPC person hand-rolling Fortran nor rely on weird one-off special case libraries to use the above. We can build libraries of high-level primitives -- think map/reduce -- and even to the level that compilers can make it look like "normal" haskell. Most things can compile down to prefix scan. This is similar to Impala/Spark figuring out RDDs/dataframes and doing SQL on top, except again, for 10-100X better performance, and you don't have to contort everything into 1970s SQL. RE:Prefix scan in particular, we don't _have_ to implement all the algs as prefix scan, but it's reliable base case, and where possible (most cases!), we nowadays instead swap in more efficient hand- written CUDA library calls.

Nowadays, when GPUs are in the cloud, Moore's Law stalled out for CPUs but is still going strong for GPUs, and most big data systems realize their latency and data shuttling/serialization sucks, all ^^^ is a big deal. See 10yr AWS price chart I calculated: [https://twitter.com/lmeyerov/status/1247382156487213057/phot...](https://twitter.com/lmeyerov/status/1247382156487213057/photo/1) . You can just code your Python dataframe code in [https://rapids.ai/](https://rapids.ai/) and not really think about it, just know you're doing better than the hadoop stuff underneath and without managing a dirty horde. The existence of NESL and the research area that came after means we're still at the beginning of swapping out crappy CPU software for better data parallel stuff, and _it's doable_.

<comment><USER4> Thanks for a thorough answer!

</comment></comment></comment></comment></comment><comment><USER5> Great slides near the end, this project looks really fun, and it's cool to see parallelism applied to simple vanilla code--rather than having to build the transformation through some eDSL. That said, I hate to be a downer, but I've really moved away from Haskell, so I don't see myself playing with this. Lately it's PyTorch or PySpark, with an eye on Rust, and mildly Julia.

<comment><USER6> > but I've really moved away from Haskell

Eh? Some sort of ML (or maybe Lisp) is going to be at the cutting edge in something like this where you have JIT-compilers and such.

> Lately it's PyTorch or PySpark

There's some GPU stuff you can do in Python via Futhark. It's very cool.

</comment></comment><comment><USER7> I saw her keynote of this talk at Lambda Days, and it was easily my favorite talk there this year (except mine, of course :) ).

I find it kind of weird that, outside of academic circles and the like, Haskell is largely dismissed as "not practical"; I think the "cabal hell" days before Stack came out really hurt the language and its adoption. Libraries like Accelerate really demonstrate how powerful something like Haskell can be when applied correctly.

</comment><comment><USER6> I'd love for this to get more mainstream attention! J, Futhark, Accelerate all have very neat stuff under the hood.

<comment><USER8> I second J and Futhark. I love J, and I wish there was a way to use the GPU with J. I have looked briefly at APL -> TAIL -> Futhark, but I don't know enough to do something useful with that particular toolchain or wow myself enough to keep going. More studying...

<comment><USER9> How about co-dfns? CUDA accelerated APL!

[https://github.com/Co-dfns/Co-dfns](https://github.com/Co-dfns/Co-dfns)

<comment><USER8> Yes that is Aaron Hsu's work for APL on the GPU. I was hoping for a J on the GPU toolchain.

</comment></comment></comment></comment><comment><USER10> I'm no expert on parallel algorithms but, based on some of the examples I've seen, I think MATLAB might be suitable.

At least when I program in MATLAB instead of python I think very differently.

</comment><comment><USER11> She is also one of the inventors of associated types.

</comment><comment><USER12> Would it give me academic credibility to have written parallelizable conditionals without 'if' statements?</comment>


Ask HN: What do we know about FB candidates profiling? - <AUTHOR> Does Facebook have access to candidates full profiles and browsing history to run a quick background check? Some companies ask for your FB profile URL. What does Facebook itself do when someone applies for a job at their company? <comment><USER2> FB sure has access to everything you put on FB. They are selling the ability to track a person from point of click to point of sale so they have access to data far more intrusive than a background check.

Do they have access to check your criminal records and tax records probably not.</comment>


Show HN: SecureIT – Easy to setup cybersecurity service for free - <AUTHOR> I have built this service to allow every project to have basic cybersecurity, in an easy to setup way.
It will basically alert you when your service/server is running on vulnerable software.
The website is: https://secureit.io
You can even try it anonymously at: https://beta.secureit.io/tryit
And you can also join in on the discussion and show us some love on ProductHunt as we launched there today
https://www.producthunt.com/posts/secureit
Thanks for caring, I did this mainly to help out starting businesses/projects - and it will always stay free for those without revenue, as I can afford to do so.
All feedback is welcome!
Cheers! <comment><USER2> Bug:

Cut & paste fails when the output from "dpkg" contains a percent sign, such as for the package libmodule-refresh-perl

"tool to refresh %INC files when updated on disk"

The resulting error is:

bash: printf: `I': invalid format character

<comment><AUTHOR> Thanks Tepix!

Will be taken care of

</comment></comment><comment><USER3> > Easy to setup cybersecurity prevention service for free

> I have built this service to allow every project to have basic cybersecurity > prevention, in an easy to setup way.

You're preventing cybersecurity?

"Preventing cybersecurity" sounds like a good descriptor for "corporate red tape" not "preventing [the lack of] cybersecurity".

<comment><AUTHOR> Freudian slip, this is a Russian scam!

j.k. updated it the post! thanks and cheers!

BTW, because of fears of that is why I allow anonymous usage.

Did you get a change to try it out? WDYT?</comment></comment>


What do you use for service discovery? - <AUTHOR>

There's a ton of choices out there - etcd, zookeeper, and more.
What are some of the pitfalls I should be aware of?
Should I keep things simple and roll my own using Redis backed by sentinel/clustering? <comment><USER2> Can someone give a really brief description of what service discovery is, and when/why one would need it?

What's wrong with simply having a config file that tells your code the URL for each service it depends on (assuming my understanding of what discovery is is valid)?

<comment><USER3> Once you start thinking about immutable infrastructure and auto-scaling, service discovery becomes very important.

Let's say you have a load balancer with 4 web servers behind it, each with its own IP.

If you hit a traffic spike, you'd like your system to automatically provision another web server and add it to the load balancer with no manual intervention.

With a Service Discovery server, your load balancer could be polling the server for a list of nodes it needs to add or remove from its pool. It could also send a signal to the service discovery server that will indicate that it's dealing with a higher traffic threshold. This signal can then be captured by another Provisioning service (also polling Service Discovery) which then triggers the building of a new web server. The web server could then signal to the load balancer to add it to the pool.

Without a system like this, a person has to go in and manually update the configs on all the relevant servers. The idea behind service discovery is to prevent that.</comment></comment>


Ask HN: What makes a great personal website? - <AUTHOR> I'm getting ready to make a new personal site and wanted to grab some opinions from the HN community as to what makes a great personal website.<p>What's the one or two things you look for when exploring a new personal site? Feel free to mention your own personal website or portfolio site as well as other personal sites you find noteworthy. <comment><USER2> Depends what you want to make. A personal site is just that; personal. No one can really say you're wrong to build it a certain way or say it shouldn't be too simple/fancy.

If I had to give any advice though, it'd be to think about what you want your personal site to do or demonstrate. Do you want to list your blog posts/articles/essays? Then maybe consider something a bit simpler in terms of design, with a focus on readability and loading times. Are you a designer/artist who wants to show off their skills? Then you'll probably want a fancier looking site with pictures/videos/demos of your work front and centre, like a portfolio.

And if you're a programmer/software engineer who wants to demonstrate that, go all out with the fancy tech and use your HTML/CSS/JavaScript skills to make something flashy. Remember seeing a developer portfolio/personal site posted here before which played out like a 2D platformer level, which was quite interesting.

Either way, it's your site, and the target audience/purpose of said site matters.

</comment><comment><USER3> Style and storytelling.

Style: Is the site intentionally designed?

Storytelling: Does the site communicate its purpose (or lack thereof) well?

I've been cataloging a bunch of personal sites (300+) if helpful here: [https://www.are.na/tmm/personal-sites- iouu5rp4cra](https://www.are.na/tmm/personal-sites-iouu5rp4cra)

My site is at [https://meagher.co](https://meagher.co). Happy to chat about this subject further - email in bio.

</comment><comment><USER4> \- Optimize your images. If you're gonna go down the tedious "hero image" road, DON'T make visitors download 10-meg background images.

\- Build it with simple HTML & CSS. JS should not be necessary.

<comment><USER5> > JS should not be necessary.

This x1000. However, not using JS is also not necessary. There are valid reasons to use JS even in a simple personal site.

The way I see it, keeping it as simple as possible is most important. Much of the time that means HTML & CSS only, maybe however, you want to have tabs at the top (for example). Is this possible to do with HTML & CSS? Yes. Is it simpler to do with JS. Also yes, and it doesn't take hardly any to do.

<comment><USER6> There are certainly valid reasons to use JS, and it can greatly enhance a site if done right - interactive examples in a blogpost is one of my goto examples where JS can enhance things a lot. Same with comment systems that allow you to see a real-time rendering of what you are writting.

</comment></comment></comment><comment><USER7> It mostly depends on who you're aiming the website at. Recruiters? Researchers? Conference organizers? People who use your software? Those will all be looking for different things so make sure to show exactly what they want to see.

I took an extremely minimal approach: Single page, text-only, no CSS, just a short introduction and contact info. The page is PGP signed and includes a tiny easter egg that a techie might notice but is inconspicuous enough to everyone else (I really tried not to make it seem pretentious lol) - it's all about "show, don't tell". [https://besa.uber.space/](https://besa.uber.space/)

</comment><comment><USER8> Really depends; some people have personal sites all about a specific niche. If I have no interest in that area then it shouldn't be interesting, but oftentimes the passion comes across and the sheer enthusiasm makes it interesting.

Mostly I click on random "personal" sites either because I want to learn about that specific individual, or because of a google-search.

So I'd say it would be nice to see a picture, or have an "overview" or "about Bob" page, to give a little summary.

But at the end of the day you decide what you want to write, share, post, or create.

For what its worth my own site has some mixed content, but generally it's about software, security, and making my own hardware. [https://steve.fi/](https://steve.fi/)

</comment><comment><USER9> Meta: Make sure to check out the ton of previous threads about blogs people like or personal sites.

</comment><comment><USER10> Clean design. Clear and thoughtful writing.

For some inspiration, have a look here: [https://news.ycombinator.com/item?id=23626929](https://news.ycombinator.com/item?id=23626929)

</comment><comment><USER11> A great personal site is the one that follows one or a couple of themes (or at least vaguely related themes), isn't too opinionated on the subjects it covers, gets updated regularly, has easy navigation, subscription feed (even if it isn't a blog), is readable without js. Having a differently designed - memorable website is good but it shouldn't be at the expense of usability.

</comment><comment><USER12> Make it _yours_. Don't copy others, in style or content. Be passionate about it. If you left one thing behind on this earth make it your website. It's your digital personality. Fill it full of fun stuff that gives you joy. Don't make it for other people, don't go chasing [waterfalls] visitors.

</comment><comment><USER6> The same thing I value in any other site: interesting content.

Secondarily, and required to make it a great site, would be speed (I should be able to start reading in at most 0.2 seconds from load in an ideal case) and internal links so that I can easily find more of the great content.</comment>