Phobos First!

[thereiwas]

Useful table. Does that "Phobos & Deimos LEO 1.8" include decelerating to LEO velocity after the 'fall' from Mars?

 

[keermalec]

It certainly involves aerobraking at Earth. The numbers given here (many thanks Nauteus!) indicate propulsive delta-vs with aerobraking wherever possible.<br /><br />From Phobos to Earth, my own calculations give 2.0 km/s propulsive (0.02 to leave Phobos, 1.88 to leave Mars, 0.1 mid-course corrections, assuming Mars is at its average orbital radius of 1.52 AU) and 3.6 km/s aerobraking at Earth.<br /><br /> <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>

 

[keermalec]

It IS a wacky idea, but it works!<br /><br />Don't you love it when something so totally counter-intuitive turns out to be the best solution? Water from Phobos or Deimos can quite reasonably be cheaper than from Earth and could very well open up the road to Mars. <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>

 

[dragon04]

<font color="yellow">Looks like Dragon will pledge to 'fight tooth and nail' over future proposals but cannot be bothered to stick around in this thread and defend his provocative position.</font><br /><br />With the inflammatory tone of the rest of the post I plucked this quote from, what purpose would it serve to comment any further?<br /><br />You're looking for a fistfight (like you always do) instead of dialogue.<br /><br />As a space fan and taxpayer, I'm dead against any manned mission to Mars that doesn't include a landing and a nice long stay. It's that simple, really.<br /><br />Certainly, I'm entitled to my opinion, right? <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[spacester]

Oh, Hi Dragon, how you doing?<br /><br />See, I was just having a little fun . . . <br /><br />Thought you'd be back and we could have some fun . . .<br /><br />And then you didn't and um . . . I waited . . .<br /><br />Sorry.<br /><br />It IS a provocative comment. Seems rude of me to NOT be provoked, right? hehehehe You WERE looking for a reaction, right?<br /><br />'Flags and Footprints' are fightin' words to some space geeks, but not me. It's just that the thought of going to Mars in such a way as to make it likely that it's 'go once and never return' drives some of us crazy.<br /><br />I prefer Settlement right from the start. And that might mean setting up infrastructure first, and that might happen on Phobos first. But I imagine that a well-thought-out plan like that would get your approval once explained.<br /><br />I've just been yanking your chain a bit lately, to keep you on your toes.<br /><br />Are you still running for POTUS?<br /> <div class="Discussion_UserSignature"> </div>

 

[dragon04]

<font color="yellow">I prefer Settlement right from the start.</font><br /><br />I'm pretty much on board with that as well. In fact, I would be very disappointed to say the least if Man to Mars was a one-shot deal.<br /><br />It's my personal opinion that if we're going to go that far, it should be with permanence of presence in mind. <br /><br /><font color="yellow">And that might mean setting up infrastructure first, and that might happen on Phobos first. But I imagine that a well-thought-out plan like that would get your approval once explained.</font><br /><br />I'd be in agreement if you're saying that infrastructure would have to be set up first. I think that's pretty much a foregone conclusion for any practical manned Mars mission.<br /><br />However, where the point of contention would be with me is no matter how "well thought out", <b>why</b> Phobos first.<br /><br />What would we be saving or gaining, and how would that savings or gain compare to a mission designed to go to Mars directly?<br /><br />Actually, you just opened up an entire aspect of the issue that [d]does allow for more than just a simple opinion.<br /><br /><font color="yellow">I've just been yanking your chain a bit lately, to keep you on your toes.</font><br /><br />It's a dirty job, but someone's got to do it. You do it rather adeptly, I might add. <img src="/images/icons/wink.gif" /><br /><br />Been well. You?<br /><br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[gunsandrockets]

<why Phobos first.><br /><br />Well for one thing you could bypass the legislative prohibition working it's way through congress which forbids development of a manned Mars mission. <br /><br />How to beat the ban of humans on Mars<br />

 

[j05h]

<i>> I'd be in agreement if you're saying that infrastructure would have to be set up first. I think that's pretty much a foregone conclusion for any practical manned Mars mission. </i><br /><br />Mars Direct and the various DRM propose placing crews directly on the surface. What I'm talking about is building either a mining station, base or at least supply cache above Mars. Orbital assets provide extremely important safety features for any Mars crews. With people, this will take several years building out the site, sure, it can be followed by a landing of that crew. My specific proposal would be a private propellant-production/tele-operation mission to Phobos supporting surface projects.<br /><br /><i>> why Phobos first.<br />What would we be saving or gaining, and how would that savings or gain compare to a mission designed to go to Mars directly? </i><br /><br />Basing from Phobos (or orbit or Deimos) allows for early global access to Mars. It creates caches of supplies that can fairly easily be placed were needed on the surface. It puts significant resources at the top of a gravity well. If a Martian moon has water, it provides the cheapest "gas" in the Solar System. The Martian moons offer an interesting platform for global, large-scale tele-robotics. <br /><br />On top of all these forward-looking advantages, Mars orbit offers us something truly unique: it is within our grasp with existing space hardware. "All" it takes is an FGB, a couple of capsules and some comsats.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[dragon04]

<font color="yellow">If a Martian moon has water, it provides the cheapest "gas" in the Solar System.</font><br /><br />That's just it. IF the Moon had been made of green cheese, we wouldn't need dairy cattle any more, either.<br /><br />We've spent a lot of money exploring Mars. Let me say that again. Exploring Mars.<br /><br />I won't argue that a supply depot on Phobos wouldn't have advantages. I won't argue that operating to and/or from the top of Mars' gravity well could have its advantages.<br /><br />However, considering the cost in money, resources, and time compared to directly landing on, and taking off from Mars, it seems pointless to stage from Phobos on the "front end".<br /><br />We <b>know</b> there is water on Mars <b>in abundance</b>. If we can make propellant on the surface, doing so from orbit seems like an arbitrarily unneeded step to me.<br /><br /><font color="yellow">Basing from Phobos (or orbit or Deimos) allows for early global access to Mars. </font><br /><br />I'm not altogether sure what you mean by that statement, or why it's so important.<br /><br />And and every Direct mission launched from Earth has global access simply be deciding where and when to de-orbit.<br /><br /><font color="yellow">On top of all these forward-looking advantages, Mars orbit offers us something truly unique: it is within our grasp with existing space hardware. "All" it takes is an FGB, a couple of capsules and some comsats.</font><br /><br />I think this is the biggest point of contention I have.<br /><br />Yes, for the largest part, we have the "exisiting hardware".<br /><br />However, that "existing hardware" has to be built, adapted, and sent. It's not like we have the stuff laying around in inventory waiting to be used.<br /><br />It adds considerable cost to the ultimate goal of establishing a manned presence on Mars. An unneccesary and prohibitive cost, IMO.<br /><br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[keermalec]

<blockquote><font class="small">In reply to:</font><hr /><p>We know there is water on Mars in abundance. If we can make propellant on the surface, doing so from orbit seems like an arbitrarily unneeded step to me. <br /><p><hr /></p></p></blockquote><br />OK, here are some numbers that may help explain why producing propellant on Phobos first could be more interesting than landing on Mars directly:<br /><br /><br />Assuming:<br />---------<br />1. 40 tons of useful payload on martian surface<br />2. LEO departure delta-v = 4.0 km/s (Hohmann transfer)<br />3. LMO departure delta-v = 2.15 km/s (Hohmann transfer)<br />4. A single space habitat including aeroshell is used for both trips (aeroshell designed for 5.5km/s Mars atmospheric entry velocity and 11.1 km/s Earth entry).<br />5. LOX/LH2 propulsion<br /><br /><br />Scenario 1: All propellant is sent from Earth, except Mars ascent propellant to be produced locally on martian surface:<br />-----------------------------------------------------------------------------------------------------------------------<br />Habitat + aeroshell designed for 11.1 km/s entry velocity: 30 + 14 = 44 tons<br />Ascent vehicle: 4 + 8 = 12 tons (dry mass + locally produced propellant)<br />Surface payload: 40 tons<br />Descent vehicle containing dry ascent vehicle, surface payload, and 5.5 km/s aeroshell: 58 + 12 + 5 = 75 tons (dry mass + propellant + aeroshell)<br />Return booster: 8 + 34 = 42 tons (dry mass + propellant)<br />Mass sent to LMO: 44 + 75 + 42 = 161 tons<br />Initial mass in LEO: 569 tons<br /><br /><br />Scenario 2: Return and landing propellant to be produced on Phobos, Mars ascent propellant to be produced locally on martian surface:<br />-----------------------------------------------------------------------------------------------------------------------<br />Habitat + aeroshell designed for 11.1 km/s entry velocity: 30 + 14 = 44 tons<br />Ascent vehicle: 4 + 8 = 12 tons (dry mass + locally produced propellant)<br />Surface payload: 40 tons<br />Descent vehi <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>

 

[dragon04]

<font color="yellow">Net savings induced by producing propellant on Phobos = 163 tons less initial mass in LEO!</font><br /><br />Perhaps true, but at your calculation of $1.6 billion US savings per launch would it take to justify the expense of Phobos First? 10? 20? 50?<br /><br /><br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[keermalec]

Don't know, we're talking about a robotic mission here. <br /><br />Production rate should be about 46 tons every 26 months (the time lapse between two favourable Earth-Mars conjunctions, therefore the minimum time between two manned missions).<br /><br />I believe an investment of 1-2 billion could do it, but we're talking non-existing technology here and developement costs could be anywhere. <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>

 

[dragon04]

1 to 2 billion to set up a robotic manufacturing infrastructure on Phobos?<br /><br />Multiply that by 25 or 50.<br /><br /><font color="yellow">but we're talking non-existing technology here and developement costs could be anywhere.</font><br /><br />And what would be the cost to <b>develop and implement</b> that technology?<br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[keermalec]

<blockquote><font class="small">In reply to:</font><hr /><p>1 to 2 billion to set up a robotic manufacturing infrastructure on Phobos? <br /><br />Multiply that by 25 or 50.<p><hr /></p></p></blockquote><br />Fine, I will work it out for you. Producing 46 tons of propellant in 26 months is about 60 kg / day. We are not talking about some massive industry that needs to be launched to Phobos but more something the size of a large space probe, and these typically cost less than 1 billion to develope, acquire, launch and operate.<br /><br />Let us base ourselves on SEI's lunar water extractor, which is estimated to weigh 21 tons and produce 480 kg of LOX/LH2 per day. Ours should weigh around 2.6 tons to produce 60 kg/day. SEI's developement and acquisition cost is estimated at 1.24 billion USD. Let us double our cost per ton wrt SEI's and estimate it at 310 million USD.<br /><br />Using a Delta-IV Medium+ to launch the mission to Phobos should cost another 160 million USD.<br /><br />We are therefore talking about a 500 million USD investment for a propellant production facility on Phobos. Doubling or even quadrupling that figure still gives a net advantage to establishing a propellant production facility on Phobos before sending a manned mission to Mars. <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>

 

[thereiwas]

Electrolyzing 60kg needs 258 kW-Hr of electricity. Assuming round the clock nuclear operation, that is about 11 kW to do that much per day. (not counting compressing, pumping, and refrigerating) How big is a 20 kW reactor?

 

[scottb50]

The ISS system is supposed to produce 110kw/hr when it is complete and is about an acre in area. With the rapid increase in efficiency being reported roughly two acres of solar cells would be adequate.<br /><br />Compressing and pumping would be relatively simple and refrigeration would only be needed for propellant needs, so it could be kept to a minimum. <div class="Discussion_UserSignature"> </div>

 

[keermalec]

Solar array efficiency at 1.52 AU from the sun would be about 39 W/kg. Therefore, producing 11 kW requires 282 kg of solar arrays. In the SEI scheme, part of the power comes from a nuclear reactor. In our scheme, we may prefer an all-solar power supply (due to size limitations and also to keep costs low), though that may mean some extra mass/kW produced and a necessarilly polar location on Phobos to obtain constant sunlight. <br /><br />My 2.6 ton estimate above may have to be readjusted to 2.7 or 2.8 tons to account for this. Other mass inefficiencies (wrt the SEI scheme) may also crop up due to the smaller size of the equipment but even at 3 tons the basic mission outline shouldn't change too much.<br /><br />For information, a Delta IV Medium+ can send about 3.2 tons to Phobos. <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>

 

[thereiwas]

Remember the 11kW is just for the electrolyzing. Budget more for pumping, melting ice, etc. That's why I said 20 kW. Actually I haven't done the calculations for energy needs for melting 60 kg of very cold ice in 24 hrs.

 

[keermalec]

<blockquote><font class="small">In reply to:</font><hr /><p>Phobos and Deimos have been scanned using radar (from the Earth!) to see if there is any sign of ice there. There does not seem to be, at least to a depth of about a kilometer. <br /><br />The theories that surround the length of time that they have been there suggests that they would have lost their volatiles by now, and there's no sign of them at present. <p><hr /></p></p></blockquote><br />Maybe you are referring to the spectrophotometry carried out by Rivkin et al. in 2001. This demonstrated that there was no water on the surface and that the leading edge of Phobos looked more like a T-type asteroid (no water) than the trailling side, which was more comparable to a C-type asteroid (water).<br /><br />Fanale, cited by Kuck estimates that ice can be found 100m below the surface at the equator and 20 m below the surface at the poles on Phobos.<br /><br />The Phobos-2 spacecraft established in 1989 that significant outgassing from Phobos could account for the larger-than-expected solar wind perturbations found in a torus-shaped region along its orbit.<br /><br />Combining this with our knowledge of C-type asteroids (of which Phobos is a member) and the nature of chemical compounds which condensed to form the planets and asteroids at that distance from the sun (of which water is a member), it seems highly probable that water exists within Phobos and is slowly outgassing.<br /><br />I have just learnt that a workshop was held on this precise subject at the NASA Ames ressearch CEnter only a month ago. <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>

 

[j05h]

Standard chondrite or more water-rich, the trailing side of Phobos still has more volatiles than Luna, and is energetically far easier for transportation. Tenative goal is shipping 2000t of water back to LEO or EM-L1 at first available window and continuing to do so. 100m is reasonable depth to be digging into for industrial water, I'm looking for oceans to live in space, things like doming Stickney Crater with ice and filling it with water and trees. Tunneling into Phobos would provide shielding and the resources to build new infrastructure, including local Habitats and new spacecraft.<br /><br />My initial plan for Phobos First would provide years of real-time VR/teleoperations across cis-Mars space. Phobos First would put a crew on-orbit to remotely build out Mars sites for other parties, for explorers, miners, settlers. When the crew has set up a landing facility (beacon, power, robot-deployed hardware), their customers descend in a minimal capsule to the surface site. Does the first crew to Phobos land on Mars? They should but it depends on circumstances. Is this viable as a business model? How about as a "South Pole" style base? <br /><br />For NASA and RKS now, if they wanted to do it, they could go using the DOS 9 core, the mothballed nuclear engine or standard upper stages and admittedly a ton of new hardware. For treating Mars like a laboratory, Phobos-based teleops makes a lot of planetary-preservation sense. It also makes sense as enabler for new industry. Obviously my focus is on doing it commercially, but if NASA and several universities wanted to get in on a Phobos base, it would be incredible. <br /><br />Phobos (or Deimos, I'm not picky) makes sense in all sorts of ways. Immense resources at the top of a major planet's well. Easier to reach with today's tech than the Lunar surface, since it's freefall all the way. In the distant future, these little moons can be gas station and shipyard for the whole System.<br /><br />Significant outgassing would be a st <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[gunsandrockets]

<Phobos and Deimos have been scanned using radar (from the Earth!) to see if there is any sign of ice there. There does not seem to be, at least to a depth of about a kilometer. ><br /><br />Please provide a link to a source that verifies your statement.<br />

 

[thereiwas]

Can a tree grow properly in near-zero gravity? <img src="/images/icons/smile.gif" /><br /><br />A neat trick from the Red Mars novels is that they intentionally left a bunch of stuff at Phobos with a small crew, to be used on Mars later. But they didn't know exactly <i>where</i> on Mars to put it. Once the surface crew sent explorers to the North Pole to verify the nature of the ice and the exact spot to put the ice-mining factory they radioed up to Arkady on Phobos and he then sent it to the exact desired coordinates.

 

[keermalec]

We really do not know if there is, how much there is, and how deep we will find, water on Phobos/Deimos.<br /><br />The obvious first step is a government sponsored robotic mission, equipped with a very long drill, to confirm the presence and accessibility of water. Private enterprise may/can go on from there.<br /><br />The uncompressed density of Mars is 3.74 kg/dm3 and that of its moons is only 1.76-1.9 kg/dm3. To me this is explained by the much stronger outgassing of Mars as it formed. Because Mars is so much larger than its moons, it generated much more heat as it accreted and took much longer to cool down. Because it has a low gravity (as compared to Earth) it lost many of its volatiles to space. Even so, it still contains some water as permafrost, even on the surface in places and in its atmosphere (0.03% according to my Planetary Scientist's Companion).<br /><br />Considering the much lower density of mars' moons, I find it highly probably that they are rich in volatiles. Were they composed of the same rocks as Mars, their density would be much closer to 3.74. <br /><br />Assuming the average density of volatiles found in Phobos/Deimos is 1 kg/dm3 and the average density of rocks is 3.74 kg/dm3, we obtain the following volatile proportions:<br /><br />Phobos<br />---------<br />Average density: 1.9 kg/dm3<br />Rock portion: 65%<br />Volatiles portion: 35%<br /><br />Deimos<br />---------<br />Average density: 1.76 kg/dm3<br />Rock portion: 69%<br />Volatiles portion: 41%<br /><br />These values seem to be supported by the abundance by mass of Hydrogen in CI-Chondrite type asteroids, which is around 30%. <br /><br />Unless Phobos and Deimos are full of empty spaces, it is more than probable that they have a significant portion of volatiles, but how deep? <br /><br />Even if they did not, or if the water were too deep to be easily accessed, Oxygen could be extracted from surface rocks to be used as oxydizer. Remember Oxygen represents 85% by mass of the propellant used in a LOX/LH2 e <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>

 

[j05h]

<i>> Can a tree grow properly in near-zero gravity? </i><br /><br />It is one of my personal goals to find out. Space-botany has huge potential, if it works. My working assumption is that light levels can be used to determine what gravity would normally do. <br /><br />Thank you for the point about Red Mars - this is exactly what I mean by global access. You know you'll need this piece of kit, but can't afford to leave it on Earth for a future launch window. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[cbased]

As far as I know experiments on Mir showed that in the absense of gravity plants were growing towards more light. If "gravity" was present (spinning wheel) then plants were growing "naturally" in the opposite direction to "gravity".<br />Also according to cosmonauts, the taste of veggies grown in space is no different to their Earth counterparts.