How come a lander was not sent with MRO?

[mrmorris]

<font color="yellow">"It should be weighed against deploying more rovers with the same money, because rovers will establish ground truth for particular sites for follow-on development, e.g. ISRU and Settlement sites."</font><br /><br />I understand 100% where you're coming from -- I really do. I question whether you understand 100% where I'm coming from.<br /><br />How many rovers do you think should be sent? How many do you think <b>will</b> be sent? How much area do you think any one MSL-class rover will be able to cover? Multiply that by each of the two figures you came up with above.<br /><br />I couldn't find in a quickie search the surface area of Mars. Lots of Google hits, but all the ones I checked were saying it had almost the same amount of SA as the land masses of Earth... but no actual number. Working it out as the surface area of a sphere from an equatorial radius of 3,397 km I come up with 145,011,003 km2. Using this figure, if each rover can cover 1000 km2 (pretty flipping good rover to my mind), we only need 145 thousand or so of them to fully explore the planet... <img src="/images/icons/smile.gif" /><br /><br />Now... that number is clearly statistical BS. The pictures from MRO (plus legacy data) will clearly allow NASA to rule out <b>some</b> of the planet as rover candidates... but how much? I'd like to see an astronaut step onto the surface of Mars as well. However, I'd really like the person stepping there to have a chance to step *back* onto Earth at some point. Given the difficulties involved just in getting there, we want him (her?) to step onto the absolute best portion of Mars that can be found. We don't want them stepping onto the 1423rd best spot because we didn't make the maximum use of orbiters and landers to identify exactly what the primo locations were.<br /><br />Rovers can get ground-level information at details that beggars what the best of orbiters will be able to provide. However, orbiters can give less-detailed in

 

[spacester]

Aha. I thought I had it 100% but your last two paragraphs added to my previously incomplete groking.<br /><br />Briefly, here's where we seem to differ: You seek the absolute best spot for manned missions, and don't want to settle for the 1423rd best spot. I seek a spot that is "good enough" and it very well may turn out that the 1423rd best spot is plenty good enough.<br /><br />For the record, I want to bring our explorers back alive as well. <img src="/images/icons/laugh.gif" /> I just don't think it is axiomatic that we must needs find the absolute "best spot" to do that with as much confidence as possible.<br /><br />I wonder if this difference is a result of two different base assumptions of why we would send men to Mars. I would send them to live there; the mission would be to survive and thus create an existence proof that man can indeed live there. Thus in my mind, any notion that my approach is lacking in terms of keeping our explorers alive will be rejected: that is the entire point of the entire manned program to Mars in my vision. The additional safety as one upgrades from the 1423rd best spot to the absolute best spot may turn out to be nil. IOW, for a given suite of settlement technology, there may be 2391 spots tied for first.<br /><br />Perhaps your explorers would be there to extend the science, with settlement being a side-benefit. I would take the exact opposite approach: science is good, but survival is paramount and indeed the raison d'etre for the whole program.<br /><br />Explanation of my perspective would have been better served by not using the word 'ever' - please allow me to strike that word and add ". . . for our rovers in the years leading up to human missions."<br /><br />The ". . . such that MODO makes MRO tech obsolete" was an excellent addition on your part; clarifying your position for me and bringing us into agreement there.<br /> <div class="Discussion_UserSignature"> </div>

 

[green_meklar]

<blockquote><font class="small">In reply to:</font><hr /><p>Briefly, here's where we seem to differ: You seek the absolute best spot for manned missions, and don't want to settle for the 1423rd best spot. I seek a spot that is "good enough" and it very well may turn out that the 1423rd best spot is plenty good enough.<p><hr /></p></p></blockquote><br />Considering the enormous cost of sending people to Mars, I think it is very worthwhile to take about as many pictures from orbit as you reasonably can before you land anybody. If we take the 1423rd-best spot, then later when we find the 977th-best and 318th-best spots, we're going to be slapping ourselves for not taking more pictures first. <div class="Discussion_UserSignature"> <p>________________</p><p>Repent! Repent! The technological singularity is coming!</p> </div>

 

[spacester]

<font color="yellow">. . . we're going to be slapping ourselves for not taking more pictures first. </font><br /><br />Why exactly would we engage in such self-flagellation?<br /><br />"Better is the enemy of Good Enough" <div class="Discussion_UserSignature"> </div>

 

[green_meklar]

I'm sort of speaking metaphorically. To put it more accurately, we'll regret having not taken the pictures. <div class="Discussion_UserSignature"> <p>________________</p><p>Repent! Repent! The technological singularity is coming!</p> </div>

 

[j05h]

An architecture that starts with basing in Mars orbit and provides rapid surface-orbit transport solves these issues for human exploration. With the current hardware orbitting Mars, explorers starting now would have better maps than we have of Earth. By MRO's finish, Mars will be better mapped than Earth. Building a base camp in orbit (Phobos) and extending presence to the surface allows explorers to eventually survey the 1st through 1423rd choicest spots. The most important thing to make this happen is in-situ propellant production. <br /><br />We're way off topic, so I'll add something constructive. Orbiters like MRO could be equipped with a "lawn dart" penetrator. If we baselined remote sensing craft with a 1-5kg impactor, we'd get random-sample ground truth from each mission. The technology is there to build a seismo/weather network within that mass range.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[mrmorris]

Ayup -- we definitely differ on at least two things regarding manned missions (in addition to me wanting the 'best' spot -- or at least one in the top ten). <br /><br />First -- I expect that there will be <b>at least</b> one and probably several 'science' manned missions before there is any possibility of one where they intend to live there for any extended period of time. In those initial missions, they'll be looking to extend our knowledge of the planet, and potentially looking for spots for long-term habitation. The surface of Mars is less hospitable to humans than any desert on Earth. What would make long-term survival <b>much</b> more likely is if there are equivalents of oasis' (oases? oasi? oasises? Is there an English major in the house?) on Mars where water and/or useful raw materials are available. If so, the best bet for finding them is going to be MODO.<br /><br />Second -- I think that the technology of orbiters is advancing faster than the plans for sending said humans to Mars are. From this -- I think the tech to make MRO will be obsolete before a footprint hits the dust of Mars.<br /><br />However -- both of these are opinion only. I make no claims as the the accuracy of my fortune-telling.

 

[green_meklar]

<blockquote><font class="small">In reply to:</font><hr /><p>An architecture that starts with basing in Mars orbit and provides rapid surface-orbit transport solves these issues for human exploration.<p><hr /></p></p></blockquote><br />Well, we can't be sure whether we'll set that up immediately. My guess is that we'll probably have several there-and-back missions before we set up a permanent base on one of the moons. Although, considering the long travel time, it's not impossible. <div class="Discussion_UserSignature"> <p>________________</p><p>Repent! Repent! The technological singularity is coming!</p> </div>

 

[spacester]

JO5H, I completely agree and I'm very glad you brought up that architecture.<br /><br />My only disagreement is that IMO we are very much on topic; making the decision implied in the title question requires definition of our overall architecture, which in turn is developed from a clear statement as to WHY we are going. As we are discussing the architecture, we are not just on topic but getting to the heart of the issue. IMO of course. <div class="Discussion_UserSignature"> </div>

 

[spacester]

So there we have it. This is actually more fun than screaming at each other, huh? <img src="/images/icons/laugh.gif" /><br /><br />Yours is the more conventional, more widely accepted approach. I know that and have known that for several years now. I am quite familiar with your position and I disagree quite strongly but I'm not all that willing nor prepared to try to talk you out of it; I'm just happy to get my view out there for folks to ponder.<br /><br />If I was to try to move you from your position, I would have to start getting into metaphysics and epistemology and I cannot imagine doing that without going off topic for just about everyone but myself. Let me just add one word in that direction, and please do not attach the meaning that the intelligent design advocates do to this word.<br /><br />Teleology<br /><br />Short of that huge discussion, I would just offer that IMO you are formulating policy based on assumptions as to how it will occur, as opposed to developing a policy from a pure starting point such as answering the question "Why?" <div class="Discussion_UserSignature"> </div>

 

[mrmorris]

<font color="yellow">"This is actually more fun than screaming at each other, huh?"</font><br /><br />Oh Pshaw! I don't scream at anybody. Look Ma -- no caps!<br /><br /><br />Well OK -- except for that class of people who argue passionately for lifting bodies or winged spacecraft based on nothing more than a firmly rooted certainty that the cooler a spacecraft looks, the less actual engineering (not to mention propellant & oxidizer) is required to get it into orbit. <img src="/images/icons/smile.gif" />

 

[willpittenger]

Phobos would probably cause its own problems ranging from the extremely short orbital period (something like 9 hours) to its low density. Its gravity would be both good and bad. You could propbably put a baseball into Martian orbit with your pitching arm. So spacecraft would be able to come and go readily, but everyone out on the surface would have to be tethered less they turn themselves into Phobo's Sputnik. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

All in all, I would rather have a crew stay at Mars until the next crew arrives. They might stay mostly in orbit make repeated forays down the various points on the surface (a reusable lander is a must). However, they would still be there. Suppose the folks back home want the crew to check out a new location. From Martian orbit, they would be able to do that within a few days to a few months.<br /><br />Now if we demand the crew return home after every landing and do not send a new crew until the next window, the next site will take several years to investigate. My main concern here is that we do not insist that the crew return almost as soon as they arrive. To plant some flags, leave footprints behind, leave a few simple instruments, and bring back samples is just not enough.<br /><br />We did that for Apollo. How often have humans gone to the Moon since Apollo 17? Never. We would do the same with Mars unless we make it a planned permanent stay. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[radarredux]

> <i><font color="yellow">you haven't seen the plans for MODO ... Mind you -- no one has seen the stats for it, since I made it all up.</font>/i><br /><br />Dang it! You really had me going for a second. I was thinking, "How could I have missed this announcement?"<br /><br /> /> <i><font color="yellow">Using the MRO data to throw 40 landers at Mars using the current technology & information base is liable to get us the same set of questions and answers... times 40. Answering the *new* questions will still require another generation.</font>/i><br /><br />Sometimes I wish we had the MSSD (Mars Super Simple Dart) Lander that would basically be a stick with some fletchings to provide some guidance and to keep the pointy end down. All it does is stick in the ground and then look around. At the top of the dart (the piece that would stick out of the ground) would be some lightweight sensors that could swivel around and take different measurements. They would use a low-gain antenna to communicate (slowly) with a local Mars orbiter. They would have a battery for about 10 days of operations. The goal is to make them as cheap, light, and compact as possible so that you can cram a huge number of them into a single mission.<br /><br />During the next Mars Window, a single Delta-2 launcher would launch 80 of these MSSD Landers, shooting the darts at a wide range targets all over Mars. Because they don't need light, you could shoot them into areas of higher latitude. Because you have so many, you could shoot large numbers into interesting but dangerous areas (like the side of these cliffs that have really neat layering, or into gulleys, or deep craters).</i></i>

 

[radarredux]

> <i><font color="yellow">Using the MRO data to throw 40 landers at Mars using the current technology & information base is liable to get us the same set of questions and answers... times 40. Answering the *new* questions will still require another generation.</font>/i><br /><br />I wonder if we will hit a point if diminishing returns, where we just aren't getting enough new answers from new robotic craft. And I wonder, if we hit that point, if someone will say, "OK, time to send in the humans."</i>

 

[mrmorris]

You may simply have 'replied' to my post because it was handy... or maybe not. Given that you have linked off my post, I want to point out that I haven't advocated *any* particular profile for manned missions to Mars. I've postulated a timing of unmanned orbiters vs. manned missions and advocated that we get the maximum data technologically possible prior to sending out humans.<br /><br />As to a Martian exploration team transferring back and forth from ground to orbit to ground to orbit (repeat as required) -- there's just a couple of problems. First -- you're talking about a launch and return that's in some ways as bad as one from Earth and **no** dedicated ground crew to refurbish your crew cabin & launch vehicle between trips. Second -- for your model -- the launch vehicle has to be a SSTO since there's no discarding anything if we have to re-use it later. Third -- you're talking a *lot* of propellant/oxidizer. Even using in-situ resources, you're talking about a *lot*. If I were just a little bit more bored that I am right now, I'd calculate how many times a Martian Methane-powered crew buggy could circumnavigate the planet for each round trip to Martian orbit. <br /><br />Eh -- what the heck. Maybe I am that bored. Let's work up an estimate.<br /><br />The Titan II was used to launch Gemini -- arguably the smallest capsule that's going to take a crew into orbit. Googling a couple of sites, I found that the Titan-II had 31,000 gallons of propellant in the two stages (presumably oxidizer is included in this). Mind you that was N2O4 as the oxidizer and a 50/50 blend of UDMH and N2H4 as the fuel. However, we'll assume iSP to be reasonably comparable to Methane/LOX which we'd need to use in-situ.<br /><br />The speed requirement for a 100 mile orbit on Earth is 17478 mph, and for a 100-mile orbit around Mars is 7736 mph. So we need somewhat less than half the speed for LMO as is required for LEO. Since this is all WAG's anyway, I'm going to assume that w

 

[mrmorris]

<font color="yellow">"Sometimes I wish we had the MSSD (Mars Super Simple Dart) Lander..."</font><br /><br />I like the idea of dozens of balloon rovers.

 

[willpittenger]

I was replying to your post, but I was also assuming we could make propellant from the Martian regolith. That would probably throw your numbers off a bit. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

<blockquote><font class="small">In reply to:</font><hr /><p>Lander that would basically be a stick with some fletchings to provide some guidance and to keep the pointy end down. All it does is stick in the ground and then look around.<p><hr /></p></p></blockquote><br />It takes a lot of engineering to ensure the dart would survive at those speeds. Those speeds are higher if you do not bother to orbit Mars before crashing into it. Remember, meteorites commonly do not survive an impact. Having a turret mounted camera that could survive those impacts would be incredible. DS2, did supposedly have the ability (never proven) to survive an impact at interplanetary orbit speeds. However, they did without cameras. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

I question the returns would ever fall to zero. Each new generation of robots we send has more and more capabilities. The problem is that those newer robots are more expensive. Sure, in a few centuries, we may be able to send sentient androids and ignore the problem. They would be able to do 100% of the work and even write the papers themselves -- and only androids would read those papers! Will we pay the price? I doubt it. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[mrmorris]

<font color="yellow">"That would probably throw your numbers off a bit. "</font><br /><br />What exactly kind of propellent/oxidizer mix were you planning on making from the regolith, and in what way would it affect the numbers?

 

[willpittenger]

I don't know what the combination is. Only that Zubrin proposed one. I also hope that a lunar variant could be developed and that the propellants could be made quickly enough for relatively rapid use. For the Moon, the lander would sit on the surface with the factory (pre-delivered) waiting for a crew. When one reachs lunar orbit, they call it up. Martian arrangement might be similar. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[mrmorris]

<font color="yellow">"I don't know what the combination is. Only that Zubrin proposed one."</font><br /><br />Well I can see that you've put a great deal of thought and research into this.<br /><br />In fact -- the Mars propellant production that Zubrin has proposed is the same as what I indicated in my post when I referred to in-situ propellant production. Namely he proposed (although he did *not* develop the concept) conversion of CO2 from the atmosphere into methane (water is a byproduct which is electrolyzed into H2 and O2). The link gives details information if you'd like to learn more about the process you're advocating. Given that it matches what I was talking about -- I don't see any great change in the numbers I posted. Mind you -- there were a lot of WAGs in the post -- but I did have a basis on each of the estimates that was firmer that a faint memory of something I read somewhere at some point.<br /><br /><font color="yellow">"I also hope that a lunar variant could be developed..."</font><br /><br />Given that the moon does not have a CO2 atmosphere -- it would have to be a completely different process instead of a variant of the Martian one.