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ziggy (25)

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Journal of ziggy (25)

Sunday January 25, 2004
08:27 PM

Manned mission to Mars

[ #17005 ]
So President Bush wants to send manned missions to the moon and Mars. On the news tonight, Andy Rooney pointed out a minor flaw in the President's plan for manned exploration of Mars:

Mars' gravity is strong enough that manned missions may not be able to lift off from the surface for the very long voyage home.

A quick spin around for some hard data shows that gravity is 1.62 m/s2 on the moon, and 3.69 m/s2 -- over twice as strong. Escape velocity is also over twice as great on Mars: 5.03 km/s vs. 2.38 km/s.

The problem of course is the cost of fuel, schlepping all of it to Mars, and all of the associated complications of sending all that additional weight to Mars and to the surface.

This is not an insurmountable problem, but a successful mission profile presupposes some major advances in propulsion systems. All in the name of some empty campaign promise intended to inspire the country and gain votes.


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  • This is not an insurmountable problem, but a successful mission profile presupposes some major advances in propulsion systems.

    Governmentese is eating your English!

    • Well I did spend some time on Capitol Hill past this week. Must be a lingering after effect.
  • Fuel needn't be shipped all the way to Mars for a return voyage. Most of the fuel can be produced from materials available on the surface of Mars. For example, by shipping a very modest amount of hydrogen, it is possible to generate the needed rocket fuel with the carbon dioxide that makes up the bulk of the Martian air.

    Not only does this technology already exist, but it's extremely simple and cheap to build. Martin Marietta Astronautics, working for NASA in 1993, built a Sabatier reactor capable of conver
    • Fuel to reach escape velocity isn't the only problem to solve. There's also going to be a huge energy requirement for the landing party, much bigger than what Spirit and Opportunity need. With a journey like that, they're also not going to visit for three days and come home. And even if they do bring the hydrogen with them, there's a lot of energy necessary to run shipboard systems for a few months there and back, as well as on the surface -- when atmospheric CO2 isn't available. Solar panels probably w
      • They're not even projecting a date for a manned mission to Mars, but it would, given the rest of the timeline, be at least 20 years from now. I won't worry about it jut yet. :-)
        • I must be misremembering something. When they first floated the trial balloon around the 100th anniversary of Kittyhawk, I think they alluded to a manned mission by 2015, with lunar exploration re-commencing around 2008 or 2012.

          Keeping up with history is hard! :-)

    • If they are going to produce the fuel there, I think we need to produce a fully automated return trip to and from Mars as proof of concept. If we can send a man-sized ship to Mars, harvest materials, produce fuel, and return, all without human presence, then we can modify the mission profile to include human beings and have more confidence in their safe return.

      J. David works really hard, has a passion for writing good software, and knows many of the world's best Perl programmers