Manned Mars landing Program

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skyfolly

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I am wondering if a manned spaceship successfully landed on mars, how is it possible for it to return to earth since Mars' gravity is 2/5 or 38% of the earth? tricky business, no? any idea? the lander must need enormous power for litoff?

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JonClarke

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I am wondering if a manned spaceship successfully landed on mars, how is it possible for it to return to earth since Mars' gravity is 2/5 or 38% of the earth? tricky business, no? any idea? the lander must need enormous power for litoff? <br />Posted by skyfolly</DIV></p><p>Welcome to the boards!</p><p>Yes, it is very challenging. There have been many studies on how could be done.&nbsp; This page, http://www.astronautix.com/craftfam/martions.htm&nbsp;has summaries of most of them.</p><p>Jon<br /></p> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

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aphh

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<p>Mars Reconnaissance Orbiter orbits Mars at the mean altitude of (250 + 316) / 2 = 283 kilometers in 6720 seconds. The orbital velocity is then 7346 000m * pi / 6720s = 3434 m/s.</p><p>Let's assume for a moment, that the Mars Reconnaissance orbiter was the "mothership" of the manned mission to Mars circling on orbit like Apollo was circling the Moon.</p><p>Now the total Delta-V requirement for the Mars lander would be 2 * 3434 m/s = 6868 m/s (braking and descent to the surface, ascent back to orbit), plus some extra propellant to do a bit of manouvering near the surface when looking for a decent landing site.&nbsp;</p><p>Compare that to SpaceX Falcon-1, which provided Delta-V of 5200 m/s to some 350 kilograms of payload, and you will start to see the magnitude of the challenge of building a manned Mars lander.</p><p>Even if that 350 kilograms would have been the equivalent of 921 kilograms on the surface of Mars. &nbsp;</p>

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skyfolly

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<p>If they chose not to return to earth, at least not so soon? to live there for a long period of time. they could first send devices like oxygen transformer(ice on the&nbsp;poles of mars could be very useful)&nbsp;or labs which grow food to mars, just like they send space station modules first into orbits. this would allow human to live on mars for a very long period of time.</p><p>So this might be a good idea to test the ice on mars, to see whether it's ice like those on earth.</p><p>So i guess even a return device can be sent there first then come a manned mission. or huge containner of canned food. lol.</p>

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JonClarke

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Mars Reconnaissance Orbiter orbits Mars at the mean altitude of (250 + 316) / 2 = 283 kilometers in 6720 seconds. The orbital velocity is then 7346 000m * pi / 6720s = 3434 m/s.Let's assume for a moment, that the Mars Reconnaissance orbiter was the "mothership" of the manned mission to Mars circling on orbit like Apollo was circling the Moon.Now the total Delta-V requirement for the Mars lander would be 2 * 3434 m/s = 6868 m/s (braking and descent to the surface, ascent back to orbit), plus some extra propellant to do a bit of manouvering near the surface when looking for a decent landing site.&nbsp;Compare that to SpaceX Falcon-1, which provided Delta-V of 5200 m/s to some 350 kilograms of payload, and you will start to see the magnitude of the challenge of building a manned Mars lander.Even if that 350 kilograms would have been the equivalent of 921 kilograms on the surface of Mars. &nbsp; <br />Posted by aphh</DIV></p><p>It is not quite as bad as that.&nbsp; As much of the dV needed to land (~2.6 of 3.4 km/s) can be shed by atmospheric braking.&nbsp; So you only need 800m/s to land.</p><p>Unless you are planning to return directly to Earth your ascent vehicle can be made very small.</p><p>Jon</p><p><br /><br />&nbsp;</p> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

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JonClarke

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>If they chose not to return to earth, at least not so soon? to live there for a long period of time. they could first send devices like oxygen transformer(ice on the&nbsp;poles of mars could be very useful)&nbsp;or labs which grow food to mars, just like they send space station modules first into orbits. this would allow human to live on mars for a very long period of time.So this might be a good idea to test the ice on mars, to see whether it's ice like those on earth.So i guess even a return device can be sent there first then come a manned mission. or huge containner of canned food. lol. <br />Posted by skyfolly</DIV></p><p>Even you intend to come back (which the first&nbsp; missions almost certainly will plan on doing!) it makes good sense to send as much of your equipment on ahead as you can.&nbsp; It also makes a lot of sense to use local resources, as you suggest.</p><p>This minimises the mass of material you have to land on the surface, as the biggest proportion will always be propellant for your return and supplies for while you are there.</p><p>One way how this could be done is this study. </p><font face="Arial" size="2"><span style="font-size:10pt;font-family:Arial"><font size="1" color="#800080">http://www.astronautix.com/craft/marsoz.htm</font><font color="#000000"><span style="color:black"></span></font></span></font> <p>Jon<br /></p> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

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ZenGalacticore

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If we can launch from Earth's gravity, we'll figure out a way to launch from Mars' gravity. We'll manufacture propellant on the surface of Mars, using Martian raw materials and elements. <div class="Discussion_UserSignature"> <p>ZenGalacticore</p> </div>

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kelvinzero

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<p>Im glad that mars will be&nbsp;somewhat easier than earth!</p><p>Look how hard it is to leave this planet. Imagine if we had to drop something like the shuttle or one of those thin towering rockets down from orbit preassembled! And have it launch a few days later with no technicians to check it over!</p><p>If the moon had been a twin earth we probably still wouldnt have the technology to bring people back. All trips would have been one way. </p>

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