Plans for mobile base - on the moon...

RobS · 2004-07-07 12:10:26

This thread, plus the encounter with my friend's mobile home and the demands of my Mars novel, have pushed me to think about the question of surface vehicles a lot more.

On Earth we have a dizzying array of vehicles to choose for a variety of transportation purposes: small cars, medium cars, large cars, vans, SUVs, humvees, jeeps, light pickup trucks, enclosed trucks, large freight trucks, motorcycles, all-terrain vehicles (ATVs), campers, motor homes of at least two standard types (large and larger), mopeds, bicycles, earth movers, etc., etc.

Eventually Mars will need all of them. The question is, what do you need and when?

1. In *Mars on Earth* (Zubrin's new book about the Flashline Arctic and Utah Desert stations), Zubrin notes that an ATV type vehicle will be essential, that it can roll over very rough, rocky terrain, pull trailers, and do all sorts of other things. Clearly, something like this will be needed early. Maybe it is what most people call an "open rover" with two seats in front and storage space in back. ATVs have three wheels, not four. Four will give more stability and more emergency rescue ability; if two people in spaceuits go out on two three-wheel ATVs and one vehicle breaks down, it will be hard to haul both people back on the other ATV. So I suppose I favor a light-weight, four-wheeled open rover as one of the first vehicles on Mars. I gather from various things I have read that it could be fuel cell or battery powered and mass about 500-600 kilograms. Another analogy to this vehicle is a golf cart, but golf carts have small wheels because they are designed for paved sidewalks and flat, smooth golf courses. This vehicle will need big wheels.

2. I think my second vehicle on Mars--probably sent the same time as the first, though--would be a light truck with a pressurized cab. This would be a 2 tonne vehicle about 2 meters wide (wider than cars; more like a humvee) with a cab 2 meters deep as well (which gives a small amount of storage space behind the seats; maybe 50 centimeters). The vehicle would have to have windows on all four sides, a door on at least one side (probably the driver side) and a standard door in the rear (for docking to other vehicles and as an emergency escape). The height would not be enough to stand up inside. It would have four wheels. It would either have a methane-oxygen combustion engine or methane-oxygen fuel cells (I favor the latter if they are well developed by then; they're still experimental). It would have a simple life support system made of parts compatible with spacesuits (so that it would be interchangeable with them) and would come with a solar panel array on the roof large enough to run the life support system if the engine/fuel cell system was nonfunctional. It would have enough horsepower to pull things and to run a bulldozer blade, a manipulator arm, or a crane, which would be standard attachments. It would be able to seat three and you could stuff a fourth person inside in an emergency as well. If necessary, you could move the seats forward so one person could sleep on the seat and one on the floor behind (it would be long enough for sleeping across the cab).

A light truck of this sort would allow a team to drive from the base on an all-day field trip. They could take off their helmets and gloves, eat lunch and maybe supper, and possibly relieve themselves (a very simple waste handling system would not require a toilet; a little privacy and a bucket will do, the contents of which can be dumped on the ground outside).

There are already a remarkably wide range of items one can buy that run off the cigarette lighter of an automobile (I have a "statpower" that I bought for $150 about 1988 and it still works well. It plugs into a cigarette lighter and makes 100 watts of household current. With that I have run a computer and printer while in Yellowstone Park, for example). The truck should have a power plug or two so that a small microwave oven could be brought along to make coffee, heat up sandwiches, tv dinners, etc., and could power one or more computers or recharge spacesuit power systems.

With a truck like this, if a two or three-person team went to a geological site that was a 5 hour drive away, they could manage quite well. They could even spend the night in the vehicle if they had to. If they had a breakdown, they could stay at the vehicle until the base could send out another one to tow them back.

The truck would also have a trailer hitch.

3. A flatbed trailer. The truck would have to come with a flatbed for hauling a few tonnes of stuff around. The flatbed would mass maybe 500 kg. It could have four wheels, with or without its own braking system.

4. A "camper." This would be rather like existing campers, which can comfortably house two and can hold four in a squeeze. It would be towed by the truck. It would have its own fuel cells, four wheels, and brakes. It would have its own solar array on the roof for life support and its own oxygen and methane tanks. The vehicle would have a metal chassis but the rest could be made of plastic and be inflatable, to save weight. The camper would be about 4 meters long, 2.4 meters wide, and 2.4 meters high, and with bunk beds and a loft bed could sleep four (though two would be comfortable). It would have a kitchenette with two or three-burner stove, oven, microwave, sink, and refrigerator; bathroom with a toilet, sink, and shower stall; a table and chairs for dining together, holding staff meetings, and doing work. It would have an airlock in the rear and a door in the front that could be docked to the door of the truck cab via a flexible plastic tunnel. The airlock in the rear could also be docked to another airlock via a plastic tunnel. This way vehicles could dock together at night to form a larger temporary base. Two vehicles of this sort could support a four to six person expedition of a month or longer, depending on supplies and cabin fever.

5. A "mobile home" or "mobilhab." This would be of the sort of size of a recreational vehicle, which are usually 7 to 11 meters long, 2.4 meters wide, and 2 meters high (I'd make them 2.4 meters high, though). It could either be towed by a truck or could have its own built-in cab and engine. It would house four people comfortably. Because of its length, it would have two rooms, not one (including the cab it would have three). Many mobile homes of this length have a forward room with the kitchenette and dining area, a "water closet" area across the width of the vehicle with a toilet stall/bathroom sink on one side of a corridor and a shower stall on the other side, and a bedroom in the rear.

6. If you need something even bigger, you make your mobile home a two-story thing; it would be 2.4 meters wide, 8-11 meters long, and 5 meters high. Such a vehicle would have two rooms downstairs and two upstairs with bathroom facilities located between the rooms, and each room would have a hatch opening upward or downward to the room above or below, with a ladder. Such a vehicle could have four airtight sections and every room would have at least two escape routes (one forward or back, one up or down). Such a vehicle could transport 8 people comfortably. It would be used to send out a larger team, say, 3,000 kilometers to investigate a region, and would be accompanied by trucks (possibly with open rovers in trailers in back) and campers. The width would remain no more than 2.4 meters, which is about the maximum width of vehicles on Earth (because of the width of roads). One will want to standardize the width of vehicles on Mars because one will need to clear roads for them, especially the larger ones (which would have trucks equipped with bulldozers to clear the route in front of them).

This last size is about the size of the mobile bases we have been talking about.

To convert this into some numbers:

Truck: cab area, 4 square meters; accommodation, two for a day or so; mass, 2 tonnes without bulldozer blade or trailer or other accessories.

Camper: interior area, about 10 square meters; accommodation, 2 for a month or so, 4 in an emergency; mass, about 4 tonnes

Single-level mobile home: interior area, about 20 square meters; accommodation, up to four for a month, up to 6 or 8 in an emergency; mass, about 6 tonnes.

Two-level mobile home: interior area, about 40 square meters (comparable to the Mars Direct's ERV); accommodation, 6 to 8 for several months, 10-12 in an emergency; mass, about 8 tonnes.

-- RobS

clark · 2004-07-07 12:29:38

Interesting, but dumping human waste onto the surface of Mars violates contamination protocols. No problem with it personally, but I'm not the one who is hunting Mars bugs.

Just a thought, but what about a hover-craft of some sort?

Open RV's of some sort limit exploration time due to radiation concerns- you also have to depend on your suit more in this situation (two points of failure, suit and vehicle).

Let's approach the problem with a different set of experiences to guide us...

Imagine you are scaling Everest. Or better yet, you're making your way to the North Pole.

How might you best achieve your goal?

Go with all the stuff that you need with you? Going in heavy.

Or go in light, with your supplies prepositioned ahead of you?

Which is the plan preached by the Prophet Zubrin? :laugh:

Suggestion: two teams. First team is your geology guru's. Keep them busy setting up house on first landing, and looking around nearby. Second Team is Shirpa Patrol. Send them out to set up prepositioned temporary bases and caches that are interspersed a 1/3 day's walk from each other.

By temporary base, I mean a simple inflatible tent, cold MRE's, water, and oxygen.

once Shirpa patrol has finished setting up these temporary bases- have them return back. Send out your Geology guru's, tell them to be safe, have fun.

If there is a problem, Shirpa Patrol comes to the rescue from the home base.

Just a thought.

RobS · 2004-07-07 17:13:31

You're right, dumping human waste on Mars will only work if you are sure the surface is sterile. I think we're reasonably sure of that already. If one worries too much, you can't send people at all; germ-filled air will leak out of habitats and escape whenever the airlocks cycle.

I doubt the Martian atmosphere is thick enough for hovercraft, especially ones that have to hover above rocks. Besides, the 600 mph+ winds you'd have to make would kick up a bit of dust.

The ATV would expose you to radiation, just as walking around would. But the Martian atmosphere provides more shielding than provisions do on the flight out in the hab's radiation shelter; the atmosphere masses 200 kilograms per square meter or 20 grams per square centimeter (equivalent of 20 cm or almost 8 inches of water). The hotel the Budget Suites guy is thinking of building in Earth orbit would incorporate 4 inches/10 cm of water shielding into it. The vehicles could have shelters that do much better; if nothing else, if you put the bunks underneath the vehicles' water tanks, you'd reduce exposure considerably for 8 hours a day.

What does Zubrin say: In *Mars on Earth* he seems to advocate ATVs. In *The Case for Mars* he proposes a very light truck (500 kg only) to move the reactor and a pressurized rover to move the crew. The latter must be about the size of a camper, I think, since in an emergency it's supposed to be able to take the crew 1,000 km. I have heard privately that he now doubts the mass budget will allow the latter.

You seems to suggest no vehicles at all, just walking, or maybe hauling supplies (shelters, for example) with a hand-pulled trailer. They'll need vehicles for safety and speed getting around, piling regolith on the hab to reduce radiation exposure, moving a drill around (if there is one), etc. Vehicles will greatly increase mobility and efficiency.

-- RobS

BWhite · 2004-07-07 18:46:08

This mass budget stuff annoys me.

Everyone agrees that the MarsDirect mass budget is razor thin. Also MarsDirect will cost between $20 billion and $60 billion.

Add $300 million and buy 6 Proton shots or $600 million and add 2 shuttle C cargo shots and pre-position a big, capable, TV-sexy rover. And a mini-supply depot awaiting the astronauts.

Zubrin's Ares is shuttle B/C plus cryogenic upper. Add a shuttle C shot to each mission. ERV + supply shot + Ares crewed launch and greatly increase your mass budget with pre-positioned supplies and equipment.

If we cannot afford to pre-position a big capable rover, we cannot afford the mission.

clark · 2004-07-08 10:04:20

You're right, dumping human waste on Mars will only work if you are sure the surface is sterile. I think we're reasonably sure of that already. If one worries too much, you can't send people at all; germ-filled air will leak out of habitats and escape whenever the airlocks cycle.

Hey, like I said, I don't care. I'm not too interested in Martian bugs to begin with. However, some are, and some argue the point that putting people on Mars in any capacity will cause biological contaimination, of some type.

Leaving waste matter on the sterilized dirt of Mars is still probably a bad idea though. We don't really need to afterall.

You seems to suggest no vehicles at all, just walking, or maybe hauling supplies (shelters, for example) with a hand-pulled trailer.

Sorry for the confusion- yes vehicles, but the plan is based on the worst case scenerio when everything fails but your suit and your feet. My basic outline was to accomadate any type of vehicle that you may imagine- the underlying principle though is that this allows a certain level of flexibility while reducing overall risk.

Once little shelters are established like this you can set up regular search areas for future expeditions beyond the first mission. Think of it as seeding trails on Mars.

BWhite · 2004-07-08 10:07:07

You're right, dumping human waste on Mars will only work if you are sure the surface is sterile. I think we're reasonably sure of that already. If one worries too much, you can't send people at all; germ-filled air will leak out of habitats and escape whenever the airlocks cycle.

Mars will be nitrogen poor.

Incineration of human waste at very high heat turns it to a powder that is a sterile but useful fertilizer if applied properly.

Nothing can go to waste.

cDelta · 2004-07-08 10:19:16

Nothing can go to waste.

Pun not intended? :;):

clark · 2004-07-08 10:27:46

Waste not, want not?

cDelta · 2004-07-08 10:36:07

But in all seriousness, you do make an excellent point. Recycling systems will obviously play a very important role in early missions, and moreso later when a base is established. There is no point to bring fertilizer for the greenhouse when your crew can just produce it on spot.

Houston: Guys, you need to fertilize the plants.
Mars Crew: Right now?
Houston: Yes. This very moment. You've been eating a lot of fiber, right?

Sorry. I couldn't stay serious for long.

clark · 2004-07-08 10:52:13

You're full of it.

GCNRevenger · 2004-07-08 11:11:17

Well Bill, there are problems with that...

The biggie is landing accuracy, that is, we don't have any yet for payloads of that magnetude. Thats the whole point of carrying a pressurized rover, so you can go long distances to reach the ERV if that or the HAB module don't land close together.

The only real way to salvage the MD arcitecture and give it reasonable mass margins is to employ a nuclear rocket upper stage instead of a cryogenic upper/TMI stage, which Uncle Bob says will buy you about 50% extra payload mass over the all-chemical MD.

Oh and then you have to worry about adding another launch of the Shuttle-C, which might be an issue with launch window, and you have to pay for the TMI stage, and you have to pay for the lander, and so on... won't be cheap.

NASA's DRM-III mars mission, the one I think will probobly happen, already uses three launches of a SDV vehicle, one to put a fully-fueled ERV in Mars orbit, one flight for the acent vehicle to get up there (solving the MarsDirect teeny-tiny ERV problem) plus rovers etc, and finally one for the manned HAB that lands. Each shot will use small NTR rockets for the TMI stage and integral aerobrake/aeroshield/debries shield. The DRM-III plan largely assumes we get better at landing big things before we go, which Uncle Bob's MD doesn't "want to wait for."

BWhite · 2004-07-08 11:20:22

Send the rover with the in situ Sabatier (26 months in advance); if it lands too far away, drive it robotically to the Sabatier.

GCNRevenger · 2004-07-08 12:51:49

That would be one gargantuan rover to carry along the fuel factory and the multiple tons of liquid hydrogen and the nuclear reactor and so on...

And it sorrta defeats the purpose of having the rover with you on the manned section of the vehicle to drive to the acent/ERV stage in the event that the HAB lands too far away, especially since you don't know for sure where the HAB will land exactly before the fact.

Plus driving it by teleoperation 1000km to the HAB will take how long?

BWhite · 2004-07-08 13:30:43

That would be one gargantuan rover to carry along the fuel factory and the multiple tons of liquid hydrogen and the nuclear reactor and so on...
And it sorrta defeats the purpose of having the rover with you on the manned section of the vehicle to drive to the acent/ERV stage in the event that the HAB lands too far away, especially since you don't know for sure where the HAB will land exactly before the fact.
Plus driving it by teleoperation 1000km to the HAB will take how long?

Sorry, my language was unclear. :;):

The Sabatier flies on Ares from Pad 39A. The rover flies on shuttle B/C from Pad 39B all within a few weeks of each other 26 months before the crewed launch. (Or launch a smaller rover on Proton from Baikanur)

Fill the rover with supplies and clean underwear.

= = =

A 2nd rover is launched with the crew of MarsOne and stays in Mars orbit until rover #1 hooks up with the crew.Then rover #2 lands near ERV #2.

Otherwise, rover #2 is instructed to land close to the Mars One crew. THe Mars One crew can track the re-entry and perhaps assist with navigation.

Most of the cost of MarsDirect is R&D. What was the incremental cost of Opportunity in addition to Spirit? Building a 2nd MER was fairly cheap IIRC with the 2nd launch cost being the big budget item.

If its a once only mission, I am opposed, period.

GCNRevenger · 2004-07-08 14:16:24

The problem ultimatly is really simple, that Ares is not powerful enough to launch both a reasonable HAB and a long-range rover, at least not without a nuclear upper stage. So much about MarsDirect is limited by the launch vehicle, which is really a major limitation to the scheme.

So you want to send a third launch per-mission just for the rover? Hmmmm i'm not wild about this idea either... orbital insertion, another aerobrake, another lander, and the rover STILL won't be immediatly available to the crew on landing.

RobS · 2004-07-08 14:50:32

If one flew two cargo missions each opposition to Mars, the crew would arriving knowing the two already sent were there; and if they missed the landing site, the two for the next mission would be coming along shortly.

Risk: something goes wrong with one or the other and you end up with half your cargo even for a rescue.

I think the chance of missing the landing area is extremely small. Viking landed within 50 miles or so of the center of its target ellipse. Spirit and Opportunity did even better. I think we can make a 99% guarantee of landing within 50 kilometers or so of the intended landing site. But I suppose the question is, is 99% enough? Maybe not. Or maybe the accuracy will be much better anyway. Spirit and Opportunity hit the Martian atmosphere within a few dozens of meters of where they were supposed to go. Even the navigation of Cassini to Saturn is so good, they have been canceling course corrections. And its orbit has to be right because flybys of moons will gradually accumulate error, because the gravitational bending will be slightly wrong.

I wonder whether we can get to the point where human and cargo landings on Mars can be 90+% certain? If so, sending two missions of cargo--one before, one for the next mission--will give us 99% certainty of arrival. If we had two cargo landers for each mission and one could perform the mission adequately with only one of the four, one would have 99.99% certainty.

-- RobS

BWhite · 2004-07-08 14:55:42

The cost is R&D. Once you know how to build a shuttle B/C, which after all merely an Ares without the upper stage, incremental flight costs are relatively small.

If we budget $60 billion for MarsDirect, whats another $300 - $500 million for a shuttle B/C, to pre-position equipment?

=IF= we had a LEO to L1 tug, $75 million for Proton could deliver a moderately sized rover. Build 6 or 8 rovers at once and send them as needed on Proton. One of the supposed advantages of MER project was that buildoing Spirit and Opportunity was only marginally more expensive than building just one.

= = =

If the crewed mission cannot hit the target, we don't go.

If the crewed vehicle lands close enough to drive a flimsy rover to the ERV, why couldn't a pre-positioned robust rover drive robotically to the crew? The rover is ON Mars, driving around before the crew leaves Earth.

GCNRevenger · 2004-07-09 08:21:08

Unfortunatly you need alot more than the launch vehicle to send a payload to Mars, you HAVE to have an aerobrake shield, and you probobly HAVE to have a lander too. This would probobly make a SDV flight to Mars cost around $750M-1Bn before thinking about payload at all... tacking on a billion per mission because Ares is a few tons too small?

With Ares or Shuttle-C or whatnot, I expect that they won't cost less than $500M each minimum... Shuttle costs $1.0Bn-1.1Bn each.

Frankly all the payload sent to the Martian surface to date have been way, way, way way way smaller than what you need to send for a manned mission. Landing 40MT on the surface is an entirely different ballgame than landing a 400lbs golf cart (that didn't soft-land either), we are NOT good at things like that yet.

There will be so much stuff to go wrong on Mars, I don't think its a good idea to risk sending the rover seperatly, not until we get good at sending big things... which MarsDirect and Uncle Bob obviously don't want to wait for.

Ian Flint · 2004-07-09 11:35:41

About not being good at soft landings:

Two Viking landers made soft landings in the '70s. I don't know why NASA ever chose to use airbag technology that the Russians couldn't get to work. I guess it was to save costs. If they had stuck with...never mind, I won't rant.

The point is, if we did it in the '70s, we can do it better and with more mass now. Not a big obstacle.

GCNRevenger · 2004-07-09 12:33:05

Its a bigger obsticle than you think... the Viking landers weighed like what, a ton each? The Apollo lunar module only weighed a few tons fully fueled... but MarsDirect or Nasa DRM-III are talking about masses in the forty ton region. And, since these vehicles would have a great deal of mass per aerobrake shield volume, I would wager to say that it is a substantially different thing than the little Vikings.

Air bags? Yeah, to save on money and on mass (Nasa sent the MERs with a mega-suped-up Delta-II, not a big Delta-IV/Atlas-V/Titan-IV)

Commodore · 2004-07-26 21:06:52

Looks like something out of Mechwarrior.

The thing is, we can't build mechs on Earth yet.

Rxke · 2004-07-26 23:38:37

*wild-eyed engineer:*

"but but but... On the moon it will be EASIER because of the low gravity!"

SpaceNut · 2019-01-01 16:43:41

need to fix the artifacts in the topic but its important to remember that we will be using telerobotics and a rover simular to the apollo era until we can get more mass to the surface as a function of the zubrin moon direct plan gets started...

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#26 2004-07-07 12:10:26

Re: Plans for mobile base - on the moon...

#27 2004-07-07 12:29:38

Re: Plans for mobile base - on the moon...

#28 2004-07-07 17:13:31

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#29 2004-07-07 18:46:08

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#30 2004-07-08 10:04:20

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#31 2004-07-08 10:07:07

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#32 2004-07-08 10:19:16

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#33 2004-07-08 10:27:46

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#34 2004-07-08 10:36:07

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#35 2004-07-08 10:52:13

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#36 2004-07-08 11:11:17

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#37 2004-07-08 11:20:22

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#38 2004-07-08 12:51:49

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#39 2004-07-08 13:30:43

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#40 2004-07-08 14:16:24

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#41 2004-07-08 14:50:32

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#42 2004-07-08 14:55:42

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#43 2004-07-09 08:21:08

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#44 2004-07-09 11:35:41

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