# Tag Info

59

The Arecibo raqdio telescope has a $300\ \mathrm m$ diameter mirror. Let's consider a radio wavelength of $3\ \mathrm{cm}$ ($10\ \mathrm{GHz}$) for convenience of arithmetic. That gives a diffraction limited beam width of $100\ \mathrm{µrad}$, so at 100 light years, the signal would be spread over an area $10^{14}\ \mathrm m$ across. The Arecibo signal was ...

49

I wrote the article you are referencing. @Hobbes has it exactly correct. It is a lightweight vehicle that can launch on even a small rocket, and takes advantage of gravity assists and favorable celestial mechanics to catch Triton at just the right time for encounter with the plumes illuminated. It will image the entirety of Triton in sunlight on approach, ...

33

@SteveLinton's answer is excellent and I'll just confirm below that its logic and numbers are correct. Then I'll show that you can do it optically as well, but with 10 meter telescopes instead of Arecibos you run into a challenge because each individual light photon carries most of the total received power per second. Radio From this answer: One ...

15

Currently functional and proven technology is limited to basically no interstellar travel at all. To reach one of our stellar neighbors (like Proxima Centauri), one of the fastest space probes we have now, New Horizons, would take 54000 years. There are multiple proposed methods of sending spacecraft interstellar distances (in shorter time spans) such as: ...

14

It's a fast flyby in the $500M cost class (a Discovery mission). So not really comparable to Beresheet. A rare, low Δv trajectory (Fig. 1) enables an MMRTG-powered spacecraft fitting under the Discovery cost cap. The mission would have to be launched in 2026, for a Neptune encounter in 2038. New Horizons has effectively demonstrated the scientific ... 10 It has been used all the way to the edge of the solar system: Pioneer 10 and 11 used core memory. Voyager 1 and 2 use plated-wire memory (a variation of core memory). Viking 1 and 2 used plated-wire memory. 9 @uhoh's answers are correct in that we at LCO were the last to observe the Tesla Roadster. For some reason, a Distant Artificial Satellites Observation (DASO) circular was not issued in the March 2018 lunation with our data from MPC site code K93 or with the data from the ESA Optical Ground Station in Tenerife (J04) but the data at Bill Gray's Project Pluto ... 8 James Webb Space Telescope Program Scientist Dr. Eric Smith spoke about this on TMRO recently. The main reason is that the telescope wasn't designed to be serviced so it is not as modular as Hubble and systems are integrated throughout the telescope rather than being discrete units that can be removed and replaced like on Hubble. It was designed like this ... 6 It took me several days observing data from DSN. Here is my analysis of the fields from the XML data files. station name: Call sign for the station. friendlyName: Common name for the station (Goldstone, Madrid, Canberra). timeUTC: Time that this report happened, using Coordinated Universal Time, in milliseconds (1/1000 of second) since the Unix epoch (1 ... 5 The Active Seismic Experiment of the Apollo Lunar Surface Experiments Package carried four grenades. They weighed 2.67, 2.19, 1.70, and 1.52 pounds each. Like Hayabusa-2's numbers, I'm not sure how much of that weight was explosive, but it does give something to compare to. Source: ALSEP Flight System Familiarization Manual, p. 2-166. 5 I think you might have interest in reading more about Breakthrough Starshot, which is a project similar to what you described and already received an intial funding of 100 million USD (so I would say it's seriously considered). The basic idea is to use a solar sail that uses momentum transfered from the photons that hit and therefore propel the solar sail, ... 5 There are several factors that make this difficult: Antenna size. The largest dish antenna in space has a diameter of 10 m (Spektr-R). The DSN has 70 m antennas. A satellite with a 70 m antenna would be very heavy, maybe too heavy to get to the outer solar system. It takes a lot of energy to get to Neptune's orbit: the Voyagers are the heaviest spacecraft ... 5 The Voyager spacecraft had nearly no propulsion capabilities. They were launched on a "Grand Tour" trajectory that would use gravity assists to provide encounters with Jupiter, Saturn, Uranus, Neptune, and optionally Pluto. In order to follow this trajectory, the route the spacecraft can take past each planet is very strongly constrained. Major ... 5 It is a “Fast Mission” opportunity. These are missions that address an opportunity in the near future that would possibly be missed with the normal mission development timeline. Historically, ESA missions are classified as Large (L), Medium (M) or Small (S). The distinction is not on size of the payload, but on the technology development required for the ... 4 A single CME will impact a spacecraft from only one direction, but that direction might not be directly from the sun because a CME may zigzag en route. So unless you can know in advance from which direction it's coming, a shield just large enough to block direct solar radiation won't suffice. The farther the spacecraft is from the sun, the smaller (and ... 4 See the post Whats the farthest distance a spacecraft has been detected (except by radio) on the Astronomy StackExchange. As of 2019 Jan 7, those answers list observations of OSIRIS-REX at 12 million km, the Rosetta at about 5 million kilometers, and the Gaia at about 1.5 million kilometers (observed "systematically" at the Earth-Sun L2 location). 3 Follow-up DSN stores the data internally in a format called "TRK-2-34". It's described in DSN technical note 820-013. I've found 15 papers that refer to using this data format. Two of those papers specifically state that it is an "internal document." Also consider this blog post: This is a technical article about how to use the Deep Space Network (... 3 Not a chance. As detailed in Bill Gray's FAQ for C/2019 Q4, the velocity at "infinity" when it leaves the Solar System will be ~32.6 km/s, one of the strongest signs that this was an interstellar object. This is considerably larger than the fastest moving spacecraft, the Voyagers, at 16 km/s. So with current conventional rockets or ion propulsion there is no ... 3 Where would one deploy deep space atomic clocks? In practically any vehicle that goes beyond Earth orbit. The press releases imply that these Deep Space Atomic Clocks will form the basis of a solar-system wide equivalent of GPS. While that might be the eventual outcome, that is not the immediate advantage. The immediate advantage is that this technology ... 3 Differences in the resulting data: no close Triton flyby for Voyager 2, differences in what moons could be observed during the Neptune encounter no close Titan flyby for Voyager 1, differences in what moons could be observed during the Saturn encounter possibly a Pluto flyby for Voyager 1 probably some differences in the timing of the heliosheath encounter ... 3 Standard commercial optical fibers could be used for data transfer on the Moon or Mars, but they may have a shorter life span than on earth and worse signal quality. The radiation does have an impact on the molecular bonds of the optical fibers which can cause signal degradation. The phenomena is called "Radiation Induced Attenuation" for which you can find ... 2 Taking the numbers from July 2016 that I used to make the plot in the question, Voyager 1 was 149 AU away from the sun in-plane ($\sqrt{x^2+y^2}$) and at +108 AU out-of-plane ($z\$). For Voyager 2 those are 114 and -100 AU respectively. That means that seen from the neighborhood of the Sun, including Earth, Voyager 1 and 2 will be 36 degrees above the ...

2

Unfortunately, those slides don't provide much information on what they mean by "relay pathfinder" but the concept of using optical communication in space has been tested and is planned for several missions. NASA has previously tested optical communications during a lunar mission. This was used as a demonstration of the concept for the (now not-so-) future ...

2

what of the original purpose of EM-1 would be served...? It is hard to tell from the NASA administrator's comments in Ars Technica's Here’s why NASA’s administrator made such a bold move Wednesday: "SLS is struggling to meet its schedule," Bridenstine replied to Wicker's question. "We are now understanding better how difficult this project is, and it’s ...

2

Something different to a X-ray tube would be needed. The efficieny of X-ray tubes is very low, about 1 % or less. The frequency range of the emitted X-rays is very broad. Beam width is very poor. Pulse modulation is slow, about a millisecond.

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Sadly, the point may just be to kick the SLS folks in the butt to be on time and on budget for once, that Senate support of their laziness may be blocked by the administration. Doing the LEO assembly approach has almost too many problems. The most glaring: the SLS mission profile has the core booster imparting enough speed and altitude for the Delta Interim ...

1

It's a Toss-Up! Starman/Roadster with a 1-m telescope LCO at SAAO According to this expert answer to the question When was the last time that Starman/Roadster was seen? the last time was at 2018-03-19 03:22:33 UTC. Checking JPL's Horizons ephemeris, the positions and velocities of Roadster and Earth at that time were: x (km) ...

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I'd say that currently the answer is "at least 2.2 lunar distances". According to this source, 2006 RH120,believed to be an Apollo third stage, was "2.2 Lunar Distances", about 890,000 km, away at (re-)discovery; photos are provided at the first link. Another possibility is J002E3 a.k.a. the Saturn IVB third stage of Apollo 12 which has a similar orbit; ...

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Yes! "It is Amazing, I am Amazed" by Craig Werth & the New Horizons Team: Brian May - New Horizons (Ultima Thule Mix) [Official Music Video]

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The receiver will likely use a filter matched to the 160 cps bit rate. This will reduce the transmit power in 1KHz BW by about 7.95 dB. The filter will however have a 1 to 2 dB mismatch loss. If this mismatch loss is 1 dB then the SNR =3dB+7.95dB-1dB=9.95 dB based on the initial SNR derivation.

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