Yet another Mars architecture

Tom Kalbfus · 2013-12-01 19:19:18

Every time we move away from what nature provided, we are taking a risk. We evolved breathing a certain type of atmosphere, and if we change the mixtures of gases we breathe, we may regret it later, much as Agent Orange and DDT were at first considered harmless.

JoshNH4H · 2013-12-01 22:53:25

I think this would be relatively easy to experiment with, cheaply. Plus, anyone with half a brain could figure out that DDT and Agent Orange are bad for people, we just didn't care. Argon, on the other hand, is the definition of inert (Or at least, two rows down from it), and we really have no reason to think that it's dangerous in any way. It is 0.9% of the atmosphere, after all.

GW Johnson · 2013-12-13 15:38:52

OK, guys. No one really liked my Mars mission architectures based on nuclear thermal rocketry. So, over the last couple of years, I have worked out a one-stage reusable lander, and all-chemical transit vehicles. It's pretty much similar to my nuke stuff, except I cannot afford 16 landings, only 6, and I really had to get creative to get that done in a credible fashion. And, I have added a Phobos trip and the start of a base to the mix! I posted it today over at "exrocketman". Too big to try to bring here.

GW
http://exrocketman.blogspot.com

JoshNH4H · 2013-12-15 16:50:38

I looked that over, and it looks like a pretty strong mission plan. Just to make sure I have everything clear, its major highlights are:

Chemically fueled
No ISRU
Multiple landing sites with the primary base located in Mars Orbit
On-Orbit assembly in LEO
H2/LOX fuel used throughout

I think I've hit the major points?

I have one major point of disagreement, and it's one that we've spoken of previously in this thread:

In Situ Resource Utilization.

In saying that it's not feasible for an initial mission, you argue:

GW Johnson wrote:

Given the imperative to make multiple landings, it is the landing craft and its propellant supplies that will “drive” the mission design. This is because that will be one of the larger masses that must be “dead-headed” to Mars, the other being the propellant supply for returning the crew to Earth. Betting their lives on return propellants manufactured on Mars is unwise and unsafe, because you don’t really know your equipment will work well enough at the site you pick, until you actually try it! The answer could just as easily be “no it won’t work adequately” as “yes it will”. The point is, you don’t know for sure.
That is why in Ref 1 and 2, and this study, I send enough propellants from Earth to accomplish the entire mission safely. Anything made locally just augments that supply, making more sites potentially explorable, and making the base left behind more attractive to those who follow.

For ISRU in the general sense, this is true; however, I disagree strenuously when it comes to the fuel production techniques that people talk about in the context of a Martian colony. To review, when one talks about ISPP (In-Situ Propellant Production) on Mars, people usually talk about producing Methane/LOX fuel.

The first step to doing this is to bring along some liquid Hydrogen. This is landed on the surface. After this, the Martian atmosphere is pressurized by a machine to a couple atmospheres. The hydrogen is reacted with the Carbon dioxide to produce Methane and Water:

4 H2+ CO2 -> CH4 + 2 H2O

The methane is liquified and stored; The water is electrolyzed, and the oxygen produced is stored, while the Hydrogen is reused.

To produce the correct amount of oxygen, the Reverse Water Gas Shift reaction is also used:

H2 + CO2 -> CO + H2O

The water is electrolyzed and the Oxygen is liquified, while the Hydrogen is recycled.

Fundamentally, the use of this process only assumes the ability to land equipment on the surface of Mars, and a knowledge of the atmosphere's pressure and composition. The former is an absolute prerequisite for any Mars mission, and while surface composition may be variable, atmospheric composition is not. If we entertain the notion that the surface atmospheric composition and pressure are significantly different than that which was measured by any number of probes (Correct me if I'm wrong, but every American probe to have landed on the surface of Mars has had both pressure and composition sensors, which are all largely in agreement?)

The point is, when it comes to the atmosphere, we know what to expect and can design and test here on Earth. Because we're not trying to touch subsurface water deposits, or anything that will vary over the surface of the planet, we don't need to worry.

Begin most important part of post
What is it about collecting the atmosphere that you think is such a large mission risk? Specifically, what about this is inherently more risky, and why is it that when collecting the atmosphere "you don’t really know your equipment will work well enough at the site you pick"? Because the relevant conditions don't vary significantly over the surface of the planet, it's not a question of location but simply whether it's suited to known conditions or not.
End most important part of post

Now, having discussed my primary point of disagreement I just have a few questions/alternative points regarding a mission architecture:

Despite the fact that after a certain point in the mission your primary interest is surface operations, you launch to and from orbit each time you want to go somewhere else. This isn't what we do on Earth, and it's not really something that makes sense. Rather than doing a series of manned re-entries, a suborbital trajectory would save a good deal of fuel (An exponential amount, in fact!) by going suborbital. Even if you resist the logic in favor of ISRU, it would be safer to land the fuel on-site and confirm its location before travelling there than sending the crew; You can always send another batch of fuel, but you can't replace your crew if they perish in a botched re-entry.

Let's say you want to have the capability to travel 2000 km in one "leap". Let's model Mars as flat and assume that gravity is not variable. Note that both of these are pessimistic assumptions. Regardless, this necessitates a 2,750 m/s initial velocity and 1 km/s to slow down, for a total of 3,750 m/s (Realistically probably like 3,500 m/s because of the conservative assumptions that went into the calculation). With Methane/LOX this implies a mass ratio of 2.6, and with H2/LOX 2.2. The entry velocity is significantly slower, so the landing ellipse is going to be smaller, which will also give much more control over the aerodynamics of the entry. It will also make it possible to use "flimsier" structures than would normally be used for an orbital entry. I'm thinking of something closer to SpaceShipOne's featherwing entry than a heatshield. This may in turn reduce the rocket entry requirements and lower the delta-V even further (For example, if you only have to fire for 500 m/s, the mass ratios fall to 2.25 for Methlox and 2.0 for H2/LOX).

I'm slowly coming around to your idea of multiple sites, although I'm not sure I'm on board with your funding profile.

Finally, and this is an idea that I picked up in this very thread, you can park your ERV in a very highly elliptical Mars orbit, such that escape is only a couple hundred meters per second. From there, instead of landing a vehicle with a crew cabin, you can use the same vehicle you used to go to Mars and simply have a small Mars Ascent Vehicle that docks with the ERV in that highly elliptical orbit. This saves mass to the surface and makes it easier to send duplicates.

From a perspective of colonization it makes sense to maximize mission return by spending perhaps 50 days at each site so that you can explore it fairly thoroughly without exhausting its capabilities. Zubrin posits a rover with a 1000 km range, which is an improvement over not having one, but I believe that the idea of using rockets to explore a much more diverse sampling of the planet's surface is one with a lot of promise.

Edit: Some BOTE calculations suggest that the suborbital hopper could actually double as the MAV if the hab is left behind.

GW Johnson · 2013-12-16 09:38:10

Hi Josh:

I think you got the gist of what I did just fine, except that I'm not really against ISRU/ISPP. My emphasis was on ISRU/ISPP trials, just not bet-your-lives dependence upon them, because any of a number of things can go wrong, all of which can be site-dependent. It's risky enough as it is.

This is dependent upon the propellant combination you select, of course. The only risks I see with methlox is having to bring the hydrogen (no local water), and can we make enough tons fast enough to be useful? That's just not done with a "desktop device". Making LOX-LH2 should actually be easier, once you actually find the water. Massive buried ice would be fairly easy to mine. The rover needs a blade on its front, as well as a drill rig on its rear. Dunno whether to try pit mining or extraction by melting up the well. Have to try both, I suppose.

I went with LOX-LH2 propulsion, because the payload fraction I could achieve was 14%, vs 5% with LOX-LCH4. That makes a huge difference in the size of the lander, for a fixed payload (79 tons vs 200+ tons, same payload). Making LOX-LH2 in situ merely requires a local source of ice, something any base or colony will have to have, anyway. Anywhere you can do that, you can also make methlox, and you don't have to bring the hydrogen.

I hadn't thought about going suborbital from site to site, except as an adjunct to orbit-based exploration of very widely separated sites (4000+ km apart?). That would be fueled by in-situ propellants.

What I had in mind was one crew of 3 on the surface with the other 3 in orbit as the "safety" watch. I'd have to think about how that might work with extensive suborbital flight available, and how much equipment gets displaced with a longer run of supplies. I think it'd work, though. Any bird capable of full entry is more than capable of suborbital entry, that's no problem.

One of things you can do with your manned vehicle in low (or any other) orbit is continue spin gravity. That way, no crew gets debilitated by more than a month or two's exposure to low gee. What I couldn't do was squeeze enough performance out of a lander to match orbits with a manned vehicle in a high-apogee orbit.

I actually went through three studies this size, the first two of which were based out of an ellipse apogee'd at Phobos's orbit. The maneuvering propellants required to get the lander to a low orbit where it could function more than ate up the capture and departure savings of the high apogee. Didn't seem to matter how I arranged it, I lost more than I could gain. And that's with LOX-LH2. LOX-LCH4 was completely infeasible for trips like that.

What I finally came up with nets 6 landings with 3 landers, to the surface, plus one trip to Phobos, and the core of a base established at the site with the most accessible ice deposits. You build one manned vehicle in the vicinity of 650 tons in orbit, and you get to reuse it on other missions. You have to build 3 unmanned ships (pushed by your landers), all in the 1000 ton class. Everything but the lander assembly is nothing but docked modules. There's only 4 kinds of modules, so this will be a lot easier than building the ISS was. That's an awful lot of bang for order-of-magnitude $100B, even if ISRU/ISPP fails completely. If it works, you explore more sites before setting that base.

I tried using my usual suspenders-and-belt-plus-armored-codpiece way of thinking for this. That way, the mission succeeds, almost no matter what else happens. That's the only real difference between my plan and the others.

GW

JoshNH4H · 2013-12-16 15:09:44

Once finals are over I plan to try to sketch out a mission architecture involving suborbital transit between a few different sites. I'll post the results on Newmars somewhere. Keep an eye out :)

Regarding ISRU propellants, you say:

I think you got the gist of what I did just fine, except that I'm not really against ISRU/ISPP. My emphasis was on ISRU/ISPP trials, just not bet-your-lives dependence upon them, because any of a number of things can go wrong, all of which can be site-dependent. It's risky enough as it is.
This is dependent upon the propellant combination you select, of course. The only risks I see with methlox is having to bring the hydrogen (no local water), and can we make enough tons fast enough to be useful? That's just not done with a "desktop device". Making LOX-LH2 should actually be easier, once you actually find the water. Massive buried ice would be fairly easy to mine. The rover needs a blade on its front, as well as a drill rig on its rear. Dunno whether to try pit mining or extraction by melting up the well. Have to try both, I suppose.
I went with LOX-LH2 propulsion, because the payload fraction I could achieve was 14%, vs 5% with LOX-LCH4. That makes a huge difference in the size of the lander, for a fixed payload (79 tons vs 200+ tons, same payload). Making LOX-LH2 in situ merely requires a local source of ice, something any base or colony will have to have, anyway. Anywhere you can do that, you can also make methlox, and you don't have to bring the hydrogen.

In the Mars Direct plan, the ISPP plant is landed in the previous launch window, so that all of the propellant can be produced before the crew leaves Earth, and if the unit fails the first time, a new unit or propellants can be sent with the crew. This provides an inherent level of backup. While it necessitates the ability to launch, store, and land Hydrogen propellant, so does your mission design, and of course the amount of Hydrogen involved here is smaller.

So long as you're confident that your propellant manufacturing equipment works (which you can be confident on by testing in Mars atmosphere simulation chambers on Earth), failure to produce enough fuel would be a mechanical failure and not a design/knowledge failure, which means that the chances of a second unit failing are not strongly affected by the event of a first unit failing.

In our scenarios, which would involve fuel production at multiple sites, the fuel production would likewise occur and be verified before the crew arrives at the sites; Should fuel production fail, that site can be eliminated from the mission itinerary, and more time spent on other sites. It's unreasonable to expect that if you set up six fuel production units on-planet, all of them will fail.

I think it's interesting that you think that it would be easier, (you even implied on a first mission!) to produce H2/LOX propellant. Surface composition, water content, and water form can be expected to vary very significantly over the surface of the planet, and storing Hydrogen (Especially because of its low density and therefore its high surface area-to-volumetric specific heat ratio) is significantly harder than storing LOX/Methane.

I'm not sure what a "suspenders-and-belt-plus-armored-Codpiece" is, but your way of thinking about things usually makes a lot of sense :)

SpaceNut · 2013-12-16 21:49:52

GW Johnson I noticed an issue with the lander that is reused for launch in that the heatshield for landing and parachutes are gone so it has no abort if there is a launch problem. But maybe that is planned....

RobertDyck · 2013-12-17 00:19:21

I have argued for a robotic sample return mission. But not for it's own sake, rather strictly as a technology demonstrator for ISPP. A scout class mission, a lander the size of Mars Phoenix with a rover the size of Sojourner, just collect some samples from the immediate area. The cycle is the most important thing: launch from Earth, soft land on Mars, demonstrate ISPP, re-launch, soft land on Earth.

Once this is done, why not use ISPP as a critical technology for a human mission?

JoshNH4H · 2013-12-17 00:57:22

The argument against doing such a thing is that it is potentially a distraction from a manned mars mission and could result in a delay of schedule. Such a systems test might cost a couple hundred million dollars, after all.

I think it's a good idea, personally. I also think that the present "plans" (if you can even call them that) for Mars Sample Return are ridiculously overblown.

JoshNH4H · 2013-12-17 02:00:37

As we rapidly approach the MarsDrive plan, it also occurs to me that even better than doing suborbital flights might be to simply put your hab on wheels and drive it around. If your driving speed is 15 km/hr you can travel 1000 km in a few days and then park for an arbitrarily long period of time. Even if you desire to circumnavigate the Martian globe, it would take less than 100 days (Circumnavigating Mars is 60 days of continuous driving at 15 kph, so I'm allowing for slow stretches and detours) out of your 550 day surface stay to do so.

Now that's mobility. And Zubrin's hab masses about ten tonnes, comparable to a medium-sized truck. What I'm trying to say is that if you can build yourself a reliable enough propulsion system, a hab-on-wheels design really isn't that bad of an idea. 100 days of continuous driving at 15 kph is 36,000 kilometers (22,000 miles). There are cars on the road doing just fine with ten times as many miles on them, and this kind of one-speed, slow driving isn't particularly bad for an engine.

GW Johnson · 2013-12-17 09:33:45

Hmmmm. Mobile hab driving around. Interesting notion! Have to stay away from rough ground, though. Will need huge balloon tires, spares, and a good way to change them.

Spacenut: my lander has no parachutes, it simply does rocket braking to touchdown, once the hypersonics of the entry process end. The crew control cabin is an abort capsule on top that works the same way, being something similar to the Red Dragon design concept. The heat shields could be either low-density PICA-X, which could be used many times at Mars orbit entry conditions, or it could be low-density ceramic composite, with a potentially "infinite" service life. Either way, the limiting factor for vehicle service life is not likely to be the heat shield, unlike here at home.

One of the two big reasons I went with LH2 not methane is that any permanent base will need local water for life support, anyway. You don't want to establish a base at any site without it. The other reason was far higher payload fraction capability in a single-stage, two-way vehicle.

In my opinion, those two reasons together make solving the problems of compressing, liquifying, and storing LH2 worthwhile. That doesn't preclude making methlox, of course, because it is likely there will be vehicles that use it, too. I just didn't have one in my posted plan.

GW

RobertDyck · 2013-12-17 11:06:02

JoshNH4H wrote:

The argument against doing such a thing is that it is potentially a distraction from a manned mars mission and could result in a delay of schedule. Such a systems test might cost a couple hundred million dollars, after all.
I think it's a good idea, personally. I also think that the present "plans" (if you can even call them that) for Mars Sample Return are ridiculously overblown.

This is one reason we're stuck. The Mars community keeps saying that sample return is a distraction, so they don't want it. But without technology demonstrator for ISPP, it can't be used for a human mission. But without ISPP, the cost of a human mission is so high that Congress will never approve it. So the conclusion is nothing gets done.

GW Johnson · 2013-12-17 15:25:44

RobertDyck is largely correct in his assessment that without an ISPP demo (meaning on-site on Mars), we can't use it on a manned Mars mission. But, that's IFF lives are to be bet upon it.

If not, then we don't have to have a separate demo, we can do the demo while the men are there. If it works so much the better. If not, well, at least we have data with which to fix it.

RobertDyck says without ISPP the mission is simply too expensive. Maybe, maybe not. NASA simply does not have a good track record planning for men to Mars. It wasn't very long ago their flags-and-footprints mission was priced at $450B.

And, as near as I can tell, they still have no working efforts to incorporate spin gravity, radiation shielding with water/wastewater, and a decent non-restrictive spacesuit, nor are they paying much attention to the living space issue for a 500 day mission, much less a 2.5 year mission.

Yet many of us here on these forums have posted outlines supported by calculations for better mission plans than anything we have seen from NASA, and many of these price out in the $10-100B class. Not the $0.5T+ class. I think the $10B plans are too close to "flags-and-footprints", but that's just my opinion.

The one I just posted over at "exrocketman" is nearer $100B, but is way-to-hell-and-gone more than a "flags-and-footprints" mission: multiple landings plus the start of a base all in one trip. It could be done factor 2-to-4 cheaper with nuclear, but I think I'd rather go right now with in-hand chemical. I think NASA and DOE would botch any resurrection of nuclear thermal rocketry.

Why this wide disparity between our $10-100B plans and NASA's $0.5T plans exists is possibly a good question for Zubrin, I dunno. He knows more about DC politics-of-money. I'm just a very, very, very experienced engineer.

GW

JoshNH4H · 2013-12-17 17:38:02

RobertDyck-

I'm not saying I disagree at all, really. But it's certainly a question you'll have to answer.

While it could be construed as a risk, I think that it's reasonable to send ISRU equipment tested only on Earth in a simulated Mars environment. I think that because most situational variables are either irrelevant or replicable this isn't an issue.

Having said that, knowing NASA's excessively conservative nature, it's not unreasonable to suggest that a sample return mission could be a testing ground for technologies like surface-to-orbit communications, ISRU, perhaps the landing technologies (in micro) and various other technologies that will be useful for the mission.

I've posted a thread where we can talk about design for a sample return mission here.

EDIT: GW Johnson, go ahead and ask him! The thread is Here.

RGClark · 2013-12-20 02:12:51

JoshNH4H wrote:

RGClark wrote:
...
I'm actually not opposed to atmospheric ISRU for propellant for the return mission. What is driving my favoring using lunar propellant for Mars missions is that I really, really do not like the 6 to 8 month travel times proposed for Mars missions. Shortening this has required nuclear propulsion which still results in months long travel times. Evidence from ISS missions suggests this will result in at least some of the astronauts being incapacitated for days, in addition to the radiation and eye damage problems now revealed.
Using lunar propellant would allow huge rockets to be used to cut the travel time to weeks.
Bob Clark

The distinction that I was getting at (albeit poorly) was between visible light imagery and hydrogen-finding radar. The first cannot be used to guarantee the presence of Hydrogen, while the latter more or less can.
What's so great, or necessary about cutting the travel time? Spin gravity is perfectly fine and I think we're better off involving as few massive rockets in this mission as possible.

In addition to the health effects including radiation which won't be solved by artificial gravity, and btw we also don't know the effects of centrifugal force acting on a long term, there is also the possibility of breakdowns for missions two or more years long:

NASA equips astronauts with snorkels, absorbent pads.
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION

As it turns out, this is the second problem with a coolant loop A pump module in the past three years. But space station Program Manager Mike Suffredini said different components in the module malfunctioned and "this is not an ISS-aging-vehicle issue."

http://spaceflightnow.com/station/exp38 … pacewalks/

Bob Clark

GW Johnson · 2013-12-20 11:08:22

An MCP suit done as vacuum-protective underwear would not need any liquid-cooling undergarment, because you just sweat straight through your permeable compression underwear. No snorkel needed in the space helmet, unlike current designs, because there is no liquid to leak. Wear the same kind of outer clothing that you wear here, for each environmental condition that you face. Hot, cold, abrasive, impact hazards, etc. Fix tears with duct tape instead of dying. Why "they" never got serious about this, I cannot understand.

Artificial gravity cannot and was never intended to counter radiation diseases. You do shielding for that. There is a little shielding from metallic structures in the spacecraft, but your water and wastewater tanks offer a whole lot more. 20 cm of water takes out the solar flare risk and cuts much of the cosmic ray risk by a factor approaching 2. I don't understand why these are still issues, just do it.

As for artificial gravity, a = r*w where a = acceleration, r = radius from cg, and w is the spin angular velocity. For numbers, ratio these: 1 gee at 56 m and 4 rpm. Bear in mind that untrained civilians seem to tolerate 3, perhaps 4, rpm just fine. Also bear in mind that spinning a baton-shaped vehicle end-over-end is both stable and a very easy and convenient way to get large radii out of otherwise very practical designs. And with docked modules, it is easy to reconfigure your same baton length at each mission step, no matter how many propellant tanks you shed. It's all in how you choose to stack them up.

GW

RGClark · 2013-12-21 11:27:48

Renewed Congressional Push for a NASA Return to the Moon.
Sparked by Chinese Chang'e 3/Jade Rabbit.
Mark Whittington, Yahoo Contributor Network
Dec 21, 2013

COMMENTARY | One salutary thing about the Chinese landing the Chang'e 3/Jade Rabbit probe on the lunar surface is that it has caused a new congressional push for an American return to the moon. But will President Obama heed it?
Rep. Frank Wolf, R-VA, the chairman of the appropriations subcommittee that funds NASA, has sent the president a letter in which he urges him to hold a White House conference gathering the best minds, not only in the United States, but from among America's international allies, to devise a lunar exploration program to start within ten years. The coalition that would return to the moon would include such entrepreneurial companies such as Golden Spike and Moon Express.
Wolf is retiring at the end of the current Congress. The man who is likely to replace him as chief House NASA appropriation, John Culberson, echoed Wolf's sentiments in a recent interview. Culberson specifically singled out the presence of rare earth elements, which have become crucial for making high tech products, on the moon as a rationale for going and for not allowing the Chinese to be the sole lunar explorer.
http://voices.yahoo.com/renewed-congres … 63138.html

Bob Clark

SpaceNut · 2013-12-21 16:15:45

Finally a foot on the space race throttle....can another nation step on it as well...

GW Johnson · 2013-12-21 19:02:06

This is too expensive to be another space race. That way lies flag-and-footprints nonsense, not the start of a base or colony.

GW

RGClark · 2013-12-22 20:16:27

Six Reasons NASA Should Build a Research Base on the Moon.
A planetary scientist suggests we should "boldly stay" where no one has stayed before.
Sarah Fecht
for National Geographic
PUBLISHED DECEMBER 20, 2013

An artist's conception of what a lunar base could look like.
http://news.nationalgeographic.com/news … n-science/

Bob Clark

SpaceNut · 2013-12-22 21:27:29

Reasons to go to the moon:
1. Maintaining U.S. influence
2. Paving the way for other applications
3. Learning more about the moon
4. Assessing the health impacts of living in space
5. Learning how to build and operate an extraterrestrial base
6. Becoming an interplanetary species

We have given away the first with partnering and by not funding Nasa to stay the lead. An example is stopping the flagship mission.

Since we are not doing number 1 how can we leverage to start the next step.

Sure learning more about the moon would be nice but so would alot of other scientific activity.

We do know what microgravity yields and while we could have explore varying levers of it on the ISS the module that would have allowed it was not built.

The ISS was barely built with cooperation how can we do this base building if we do not want to really fund it so that it can be done.

Going to just the moon or Mars does not make Earth's creator a space fairing species IMO.

Quaoar · 2013-12-23 10:54:54

JoshNH4H wrote:

As we rapidly approach the MarsDrive plan, it also occurs to me that even better than doing suborbital flights might be to simply put your hab on wheels and drive it around. If your driving speed is 15 km/hr you can travel 1000 km in a few days and then park for an arbitrarily long period of time. Even if you desire to circumnavigate the Martian globe, it would take less than 100 days (Circumnavigating Mars is 60 days of continuous driving at 15 kph, so I'm allowing for slow stretches and detours) out of your 550 day surface stay to do so.
Now that's mobility. And Zubrin's hab masses about ten tonnes, comparable to a medium-sized truck. What I'm trying to say is that if you can build yourself a reliable enough propulsion system, a hab-on-wheels design really isn't that bad of an idea. 100 days of continuous driving at 15 kph is 36,000 kilometers (22,000 miles). There are cars on the road doing just fine with ten times as many miles on them, and this kind of one-speed, slow driving isn't particularly bad for an engine.

It's seems fantastic: may I have more details on your rover-habitat?

Terraformer · 2013-12-23 14:51:50

Plus, at that sort of low speed, you could explore as you're driving along with couple of small rovers or bikes.

JoshNH4H · 2013-12-23 15:32:18

Quaoar, I can't say I have many details at this time; But presumably it would be something like a habitat on the bed of a large truck.

This does result in a conflict if you're looking to use solar panels because it will be tough to carry around all the panels that you'll need. But then again most of the power would actually be needed for propellant production and not as much for the routine mission/science operations. Propellant production can occur pretty much anywhere on the planet because the crew can just drive there.

I wouldn't expect them to actually circumnavigate the planet, but it certainly would be well within the crew's ability to do so.

RobertDyck · 2013-12-23 16:03:13

You could use a SP-100 nuclear reactor. That's what Dr. Robert Zubrin used for the ERV for Mars Direct. It generates 100 kWe (kilowatt electric), the exact same power as the engine of a Toyota Prius. Development started in 1983, discontinued in 1993. With Rankine power converter, mass was about 2.4 metric tonnes. There were options to scale it up, more power requires larger radiator. Engineering went up to 1,000 kWe.

Last edited by RobertDyck (2013-12-23 17:43:06)

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