Charlie Stross on getting humans to Mars: some considerations I wasnt aware of before. Landing safely on Mars is hard. The atmosphere is too thin for aerobraking of massive payloads, but thick enough to kick up horribly unpredictable turbulence if you try and use retro-rockets. So for small payloads recent probes have used the bouncy air-bag trick ... but that involves loads of up to 20 gees on impact (not good for humans!) and maxes out at around 1000 kg of payload (or the airbags are infeasibly bulky and heavy). The big sky crane approach is promising (allows retro-rockets while avoiding the turbulence/disruption of landing site effect) but nobodys tried doing it on a payload within an order of magnitude of the size necessary for even an unfueled ascent stage capable of sending an astronaut back into orbit: an ascent stage with fuel on board would be even more massive (on the order of 40-50 tons, minimum). My gut feeling is that for putting humans on Mars, well start with teleoperated robots ... and by the time its time to go in person, well do it the civilized way, via a Martian space elevator. (Tensile strength needed for an SE on Mars is much lower than on Earth, and it can leverage the Martian moons for construction material or ballast. Its still a huge engineering job, but it may be easier than operating a reusable orbit to surface to orbit rocket shuttle.) antipope.org/charlie/blog-static/2014/11/lets-put-the-future-behind-us-1.html#comment-1961843
Posted on: Sun, 30 Nov 2014 08:18:20 +0000