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There's the old plan of Zubrin and Baker: Mars Direct. It involves manufacturing methane fuel on Mars from a small import of Earth hydrogen. 95% of the return f

by iwwr 11y ago

There's the old plan of Zubrin and Baker: Mars Direct. It involves manufacturing methane fuel on Mars from a small import of Earth hydrogen. 95% of the return fuel mass is manufactured on Mars, giving significant mass fraction savings for a launcher. Not only that, by using a nuclear thermal upper stage you double the payload, or halve the size of the Earth launcher. If on Mars you also bring along a nuclear rocket vehicle (Nerva-style) you can have unlimited, reusable global range, including Mars surface-orbit operations. Suck and liquefy Mars CO2 and use it as a reaction mass. All this was hashed out 24 years ago by Zubrin and Baker and NASA needs only a firm commitment to Mars to put it into practice. http://en.wikipedia.org/wiki/Mars_Direct http://en.wikipedia.org/wiki/Mars_Direct http://www.lpi.usra.edu/meetings/marsconcepts2012/pdf/4069.pdf http://www.lpi.usra.edu/meetings/marsconcepts2012/pdf/4069.p... - Gashopper, a concept derived from the larger NERVA hopper, this time solar powered small robot for exploration http://en.wikipedia.org/wiki/NERVA http://en.wikipedia.org/wiki/NERVA - compact nuclear reactor for space applications

tokenadult 11y ago
All this was hashed out 24 years ago by Zubrin and Baker and NASA needs only a firm commitment to Mars to put it into practice. The lessons of history suggest that a lot of ideas that only need firm commitment to be put into practice also need a lot of engineering debugging during the development process to solve unexpected problems. The Space Shuttle was based on engineering studies that somehow didn't anticipate that the whole spaceship would blow up if launched on a cold day[1] nor anticipate that the shuttle could break up on reentry if it was nicked by a piece of its own booster rocket while being launched.[2] Just as there were astronauts who took that risk on the Space Shuttle, there are surely astronauts who would risk taking Mars Direct to Mars. They might find out that the mission would end up being called Mars Direct and Bust, and never get back home. Disclosure: I am a big fan of the space program, including manned space flight, and my ambition in high school was to be the first man to set foot on Mars. I find it dismaying that I could STILL be the first man to set foot on Mars, as I thought that event would have happened by the 1980s, before many participants here were even born. [1] http://www.asktog.com/books/challengerExerpt.html http://www.asktog.com/books/challengerExerpt.html http://williamwolff.org/wp-content/uploads/2013/01/tufte-challenger-1997.pdf http://williamwolff.org/wp-content/uploads/2013/01/tufte-cha... [2] https://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0001yB https://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=...
- iwwr 11y ago
  The Space Shuttle was expensive and this was apparent even at the end of the design stage. It was hobbled by the partnership with the Air Force, where it needed a large minimum payload and specific dimensions for the cargohold. Design considerations and technology limitations also made it not very reusable. It was expensive as a human and cargo launcher and eventual savings from learning (many launches) weren't feasible to begin with. The Air Force realized their mistake and went on to develop their own separate launchers. The Shuttle continued because it had acquired momentum and had large constituency support, it was a jobs program. Nixon also favored doing one thing over and over (i.e. Earth orbit) over potentially more risky one-off deep space missions. The ISS was eventually pushed through as a way to give the Shuttle something to do, absent any other US deep space aspirations. Mars Direct lays the trail for a continued program of exploration, not just a 'footprints and flag' operation. It has interesting savings and synergies even without necessarily having reusable launchers (except for the NERVA-style hopper). Technologically it's also very conservative.
- programd 11y ago
  > The Space Shuttle was based on engineering studies that > somehow didn't anticipate that the whole spaceship would blow > up if launched on a cold day[1] nor anticipate that the > shuttle could break up on reentry if it was nicked by a piece > of its own booster rocket while being launched.[2] However it is worth noting that the engineers correctly predicted about a 2% catastrophic failure rate - that is loss of orbiter. Sure enough we lost two shuttles by mission 107. You can find the prediction in one of the two volume histories of the Space Shuttle project [1], [2]. Incidentally I think the books should be required reading for all engineers to understand how truly ambitious national projects such as the Shuttle are done. That includes the political, economic, and of course engineering issues involved. [1] http://www.amazon.com/Shuttle-Decision-1965-1972-History-Volume/dp/1588340147 http://www.amazon.com/Shuttle-Decision-1965-1972-History-Vol... [2] http://www.amazon.com/Development-Shuttle-1972-1981-History-Volume/dp/1588340090 http://www.amazon.com/Development-Shuttle-1972-1981-History-...

by iwwr 11y ago

tokenadult 11y ago

All this was hashed out 24 years ago by Zubrin and Baker and NASA needs only a firm commitment to Mars to put it into practice. The lessons of history suggest that a lot of ideas that only need firm commitment to be put into practice also need a lot of engineering debugging during the development process to solve unexpected problems. The Space Shuttle was based on engineering studies that somehow didn't anticipate that the whole spaceship would blow up if launched on a cold day[1] nor anticipate that the shuttle could break up on reentry if it was nicked by a piece of its own booster rocket while being launched.[2] Just as there were astronauts who took that risk on the Space Shuttle, there are surely astronauts who would risk taking Mars Direct to Mars. They might find out that the mission would end up being called Mars Direct and Bust, and never get back home. Disclosure: I am a big fan of the space program, including manned space flight, and my ambition in high school was to be the first man to set foot on Mars. I find it dismaying that I could STILL be the first man to set foot on Mars, as I thought that event would have happened by the 1980s, before many participants here were even born. [1] http://www.asktog.com/books/challengerExerpt.html http://www.asktog.com/books/challengerExerpt.html http://williamwolff.org/wp-content/uploads/2013/01/tufte-challenger-1997.pdf http://williamwolff.org/wp-content/uploads/2013/01/tufte-cha... [2] https://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0001yB https://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=...

iwwr 11y ago
The Space Shuttle was expensive and this was apparent even at the end of the design stage. It was hobbled by the partnership with the Air Force, where it needed a large minimum payload and specific dimensions for the cargohold. Design considerations and technology limitations also made it not very reusable. It was expensive as a human and cargo launcher and eventual savings from learning (many launches) weren't feasible to begin with. The Air Force realized their mistake and went on to develop their own separate launchers. The Shuttle continued because it had acquired momentum and had large constituency support, it was a jobs program. Nixon also favored doing one thing over and over (i.e. Earth orbit) over potentially more risky one-off deep space missions. The ISS was eventually pushed through as a way to give the Shuttle something to do, absent any other US deep space aspirations. Mars Direct lays the trail for a continued program of exploration, not just a 'footprints and flag' operation. It has interesting savings and synergies even without necessarily having reusable launchers (except for the NERVA-style hopper). Technologically it's also very conservative.
programd 11y ago
> The Space Shuttle was based on engineering studies that > somehow didn't anticipate that the whole spaceship would blow > up if launched on a cold day[1] nor anticipate that the > shuttle could break up on reentry if it was nicked by a piece > of its own booster rocket while being launched.[2] However it is worth noting that the engineers correctly predicted about a 2% catastrophic failure rate - that is loss of orbiter. Sure enough we lost two shuttles by mission 107. You can find the prediction in one of the two volume histories of the Space Shuttle project [1], [2]. Incidentally I think the books should be required reading for all engineers to understand how truly ambitious national projects such as the Shuttle are done. That includes the political, economic, and of course engineering issues involved. [1] http://www.amazon.com/Shuttle-Decision-1965-1972-History-Volume/dp/1588340147 http://www.amazon.com/Shuttle-Decision-1965-1972-History-Vol... [2] http://www.amazon.com/Development-Shuttle-1972-1981-History-Volume/dp/1588340090 http://www.amazon.com/Development-Shuttle-1972-1981-History-...