( CNN ) -- They call it the `` coolness factor . '' CNN commenters -- clearly energized about the promise of a new , privately developed space shuttle -- are buzzing about winged spacecraft versus capsule-based vehicles like Dragon , which SpaceX used for its historic visit to the space station last month . A commenter called `` gregory '' points out the Skylon space plane project in the UK . The theory behind space planes is they would be able to take off from a runway , rocket into low orbit , and then fly to a landing on a runway . Gregory suggests that space planes are preferable because their engines would be designed to `` breathe air like a jet at lower speeds '' and then `` switch to rocket mode in the high atmosphere . '' CNN reported on Skylon last year and one insider estimated development cost to be around $ 10 billion . NASA 's program to fund private spacecraft development offers only a fraction of that amount -- less than $ 400 million awarded so far . Sierra Nevada 's Dream Chaser orbiter , which passed an aerodynamics flight test last month , would launch atop an Atlas V rocket and uses wings to fly back to a runway landing on earth . `` As far as coolness factor -- Skylon wins over Dream Chaser hands down , '' gregory writes . Well , yes , experts say privately developed space planes that take off and land independently from runways would be great . If they existed . But they do n't right now . Why not ? It costs a lot of money to develop new technology . For Skylon , a crucial engine test still stands in the way of success , according to reports . Then , down the road , suborbital test flights reportedly could happen as soon as 2016 , if all goes well . Virgin Galactic 's SpaceShipTwo is n't designed to take off from a runway independently , it has to be launched in flight from a mothership aircraft . It is not intended to achieve orbit . Dream Chaser -- which aims to reach the space station -- is expected to have its first autonomous flight test in August or September . It 's based on well-known design concepts , which saves money on development costs . Coolness ? Aerospace engineers will never choose style over substance . But the sweeping , sleek design of a winged spacecraft like the Dream Chaser does catch the fancy of a lot of aerospace aficionados who still hold a place in their hearts for NASA 's retired shuttle program . Let 's not forget capsules -- such as the Apollo command module -- which traveled to the moon and back . Yes , they were gumdrop-shaped with less `` coolness factor , '' but they got the job done . More reliable than wings , say supporters , because they 're simple and more proven . As one aerospace insider put it : Sometimes the argument about winged versus capsules `` can be almost a religious debate among engineers . '' A downside of most capsules : They splashdown in the water , creating water damage , although Russia 's Soyuz capsule 's system allows it to land safely on solid ground . As CNN commenter `` Dem in Nebraska '' points out , `` Spashdown requires manpower and equipment to lift the capsule out of the ocean , which requires '' lots of expensive logistics and infrastructure . Landing on a runway costs a lot less , Dem suggests . Right now , the SpaceX Dragon is designed to return to Earth by splashing down . But the company has plans to develop the Dragon for on-target propulsive landing on solid ground . All this talk about wings versus capsules goes to a larger point : What 's the ultimate goal behind spacecraft like Dream Chaser , Dragon and Boeing 's capsule , the CST-100 ? Is it to build a vehicle that will take astronauts into low orbit ? Or does the design goal take a longer view ? A longer view may be to develop a spacecraft that can travel to low orbit and travel to the moon -- or beyond . This is what SpaceX is looking to do -- develop spacecraft that can be used for different kinds of missions .
CNN commenter : Space planes have higher `` coolness '' than shuttle . Winged space shuttle passes first aerodynamics flight test . SpaceX Dragon capsule plans to add propulsive landing on solid ground . Wings-versus-capsule engineer debate can be `` almost religious ''