Combining the Rover and Hab - Go RV'ing!

C M Edwards · 2004-03-29 09:12:51

In the Mars Direct mission profile, crew transit between the Hab and ERV is a necessary portion of the mission. This makes the rovers used by the crew a vital mission component. So, why not combine it with another vital mission component, the crew hab?

A pressurized passenger vehicle similar in size to a modern recreational vehicle (with bigger tires and a broader wheelbase, please! ) could be incorporated into the hab during the outbound trip, then disconnected and driven off the lander as a mobile base. Constructing the hab in in this fashion could allow large portions of the crew cabin to be discarded before the descent to the surface, saving propellant. Using the rover as the primary living space for the entire crew would enable a mission profile with longer surface forays over greater distance. The ERV crew cabin -- not that of the Hab vehicle -- could be used for additional living space, allowing the crew to remain close to the vehicle that they must spend their time setting up to take them home rather than spend time with a vehicle that will ultimately be abandoned.

Power and fuel may be a prohibitive requirement, as the rover vehicle would be hauling around a substantial portion of the mission architecture with it. However, the extra fuel may well prove worthwhile if the mission range could be greatly extended with a matching reduction in the propellant required for landing.

SBird · 2004-03-29 12:36:31

I think that the biggest objection is that there's no guarantee that you'll be able to go anywhere. Imagine putting wheels on a house (the hab will have to be at least that big) and dricing it around the countryside where there aren't any roads. You can go a few places but overall, you're going to constantly be stopped by impassible terrain features that a smaller rover can easily navigate. Plus, if you end up tipping your hab over or crashing it into something, you're kinda FUBARed. That said, I've seen that many of the modern hab designs have a small set of wheels for some level of mobility.

John Creighton · 2004-03-29 12:39:38

IIRC the case for mars suggested a walking habitat as a future possibility.

C M Edwards · 2004-03-29 14:08:52

The hab/rover vehicle would have to leave Earth orbit being as big as a house, but it need not reach Mars that way. The extra mass required to make the RV off-road worthy would have to be made up by a smaller final mass. Ultimately, this is a proposal to use an even smaller hab than Mars Direct, but that can be alleviated by relying on the ERV for habitation as well, and by discarding expendable cabin sections.

SBird · 2004-03-29 14:30:34

The problem is that Mars Direct is already very mass-low. You're really pushing the low end of safe with that plan. If anything, you should increase the lander mass.

What would probably be better would be a large, very capable RV in addition to the crew hab. The RV might have a 2000 km range and be capable of sustaining a crew of 3-4 almost indefinately. (RTG/nuclear/solar power) You could then make month-long extented journeys across the planet and still get back to the base.

A CH4/O2 powered ballistic hopper would also fill in quite nicely for this duty. You can just jet to an area of interest, grab some samples, camp our for a few days and then blast back to base for detailed sample analysis and refuel.

Michael Bloxham · 2004-03-29 22:48:31

Spending up to 18 months on mars, long-range mobility on the surface will be paramount for efficient exploration, as geologically interesting sites will likely be scattered far from the landing site. I heavily favor a Mars Direct plan, which as SBird has pointed-out, may be too heavy for further improvement. Perhaps a set of wheels or some sort of 'mobility package' which easily attaches to the frame of the hab could be sent ahead to mars parking orbit (where it waits in preparation for the hab to land) on a commercial launcher, landing next to the hab or ERV where appropriate landing beacons have been deployed. That way, development of mobility hardware is not mission critical, and may be delayed and introduced during the later missions.

Using (relatively) cheap commercial boosters to launch hardware ahead to mars would be greatly beneficial to any manned mars mission; delivering science packages, large rovers, spares and other non-essential supplies (and also alleviating the burden on expensive HLLV launches). This idea may have been covered by Zubrin or others. However, I feel it is something which is too often over-looked.

quasar777 · 2004-03-30 14:50:57

i`m glad this has been mentioned. i`ve pondered over this as well. why not combhine the wheels & the landing jets?

SBird · 2004-03-30 14:51:44

There's several thread going on in the interplanetary travel section that are heavily skewed towards the cheap delivery of cargo to Mars.

Algol · 2004-03-30 16:51:47

Travelling at an average speed of 30kph for 9 hours a day the equator of mars could be traversed in just under 80 days.

Makes you think, they gotta give you some spare time....... ???

SBird · 2004-03-30 17:39:38

The biggest problem is what I refer to above - the terrain. Take a standard off-road vehicle and try to get from point A to point B with no roads. It's not easy. Even worse, Mars, lacking strong erosive forces that tend to flatten out mountains, is even more rugged than Earth. A person on foot, on bike or small rover can tackle most terrain. A hab module on wheels is going to be very limited by any sort of terrain features like steep hills and canyons. Mars has both in abundance.

Having some limited mobility on the hab is nota bad idea but if you want to actually cover ground, a mobile, pressurized car or a plane/hopper is a much more practical way to go.

Ian Flint · 2004-03-30 18:07:53

Another thing that hasn't been mentioned is habitat construction. You might just wait to start the construction of underground shelters or the erection of plastic domes -- but why wait? If your going to build anything on Mars, you'll want to have a stationary base. It could be mobile but that just seems a bit inconvenient.

Dook · 2004-04-02 18:50:32

I guess it would be a good idea to be able to move the habitats closer together since they will likely not land as close as you would like them. Probably a good idea not to try and land them that close anyway. Considering how rocky the surface of Mars seems to be I think it would be better to fix some kind of plow to one of the trucks in the Mars Direct plan and clear the rocks then fix motorized wheels to the habitat support legs to drive it.

quasar777 · 2004-04-03 11:25:26

the same arguments i`ve had concerning The Moon apply as well to Mars. anything going to mars should land not only close to it`s related artifacts but also close to previously landed ones. that way the materials from them can be salvaged. this concept was used in the film "Red Planet", & in orbit in the film "mission to Mars". as a matter of fact this should become a standard in space travel. whatever govts control whatever artifacts should follow this mandate. & yes it`s a good idea not to get too close as we don`t want collisions encouraged.

C M Edwards · 2004-04-05 09:45:34

Modern guidance systems are relatively good, given enough fuel for course corrections. Probably good enough to bring one lander down on top of another -- again, given enough fuel. But fuel will be limited, and safety requires that the Hab not come down close enough to the ERV that the ERV would be in its backwash.

That means a separation of at least a few hundred meters between the Hab and ERV upon landing, possibly several kilometers. A substantial surface trek is in store for every member of the crew who wants to go home, regardless of how close the landing is. So, if you've got to cover the ground anyway, why not use a mobile Hab that can make a whole mission segment out of the traverse instead of a simple "final trek"? It could add substantial scope to the mission.

C M Edwards · 2004-04-13 15:47:16

If a Mars Reference mission profile used a transit habitat that could soak in Mars orbit – without a crew – for the entire duration of the surface stay, it would remove both the necessity of landing the entire hab on the surface after the outbound leg of the journey (using a smaller capsule instead for the landing), and the necessity of lofting an entire new transit habitat up from the Martian surface along with the ERV (just re-use the old one sitting in space, propelled using the ERV upper stage). This would substantially reduce the fuel and staging requirements on the ERV, which could then be an even smaller and simpler vehicle.

There would be four essential mission equipment components: A transit habitat, a surface habitat, a rover, and an Earth return propulsion stage. A descent module from the transit habitat would also be required, but I believe that anything big enough to bring the rover to the surface can be made big enough to bring the crew along inside the rover, reducing the role of the descent module to that of a deorbit stage and heat shield for the rover vehicle. The return stage would require a docking maneuver to mate it with the transit habitat, but could use the same docking port as the rover. This is an extra rendezvous over what would be required for a Mars Direct mission profile, but would easily knock fifty tons off of the return stage’s lift-off weight. The extra mission equipment component - a surface habitat – could be incorporated into either the return stage or a sufficiently large rover, and would not require a separate rendezvous to reach it.

In this scenario, the surface habitat would have to be sent over with the return stage, but would not have to be lifted with it. Likewise, the rover and descent capsule would not have to bring down the entire transit hab with them to reach the surface.

quasar777 · 2004-06-22 13:52:53

i`d imagine there will be times when crew would be dragging hundreds of pounds across Mars behind them on sleds. i`ve seen this in several scifi books, tho they were on the Moon.

Trebuchet · 2004-08-18 03:09:16

Sorry for practicing necromancy on a dying thread...

But perhaps you could make a mobile Mars base a different way. Specifically - with tents.

No, I have not gone mad.

What I was thinking was that if you deployed a tent (made of suitably airtight and rugged synthetic fabrics/plastics) the air pumped inside would eliminate the need for support poles and such, meaning that you could make them very light. If you had standardized doorway 'gaskets' to prevent leaks, you could park your hab for a while, and deploy a connected tent/temporary hab or two. The extra space when parked means you can cram more stuff in the actual rover itself when moving. Just toss some sandbags over the top or something (I'm picturing a cylindrical tent unit here)

You could use this idea to add some room to hab units, too, but I think it's more useful with the rovers. Consider it the Mars equivalent of those RVs with the slide-out sections when parked. Could be useful.

SpaceNut · 2004-08-18 10:48:19

Here is an article from a while ago on the topic.
http://www.spacedaily.com/news/lunar-04s.html

This link will provide more blog comments for when this article came out from the Project constellation.us site.
http://www.jburk.com/mt/mt-comments.cgi?entry_id=489

C M Edwards · 2004-08-18 13:44:27

Inflatable/deflatable habitats could indeed be the answer to the size problem. Not everything has to be the size and complexity of the full Transhab package to be useful. I'm a little worried about performance during repeated inflation & deflation cycles, but inflatable systems can accomodate that if designed properly.

SpaceNut · 2004-08-18 14:17:09

While not being a 100% on target with this topic it does have some details of interest.
Next-gen rover to practice searching for life
Researchers prepare Zoë for test in Chilean desert
http://msnbc.msn.com/id/5725501/

MarsDog · 2004-08-19 00:58:43

Perhaps a set of wheels or some sort of 'mobility package' which easily attaches to the frame of the hab could be sent ahead to mars parking orbit (where it waits in preparation for the hab to land) on a commercial launcher, landing next to the hab or ERV where appropriate landing beacons have been deployed. That way, development of mobility hardware is not mission critical, and may be delayed and introduced during the later missions.

Long trips, even in an Earth desert, pose dangers.
On Mars there will be no rescue. Limited movement, of large structures, is needed. Explorers will likely stay near the base.

karov · 2004-08-19 02:52:55

The martian rover could include many inflatable details. Indeed cause of deflating it would not be necesarry - it could be inflated once - with kinda solidifying foam and to form the pressurized hab compartment. Thus the overall vehicle mass ( empty - no fuel and crew) can be with the existing technology made quite low ( ~2 tonnes?). To Mars the rovers should be shipped in very 'folded' state and once on martian surface to deploy and inflate to rather huge sizes, but little weight. The inflatable cabin could be filled with a oam with big percent o hydrogen atoms ( plastic foam) to provide big degree of radiation shielding per unit of mass. The plastic for the foam (polyethylene?) can be produced by the fuel-making chemical plant. It should be examined the possibility the tanks for up to ~1 m3 of fuel+ the same amount of oxidizer to b also solidifying foam inflatable...

Imagine, the frame of the vehicle - unfolding, the hab on it inflatable, the tyres made of cold resistant plastics, too --- in the shipping stage the vehicle could have quite modest dimenions.

I agree with MarsDog that longer trips than several dozens of km, even if they lie in the abilities of the rover would be avoided by means of security. But closer distance transport will be vital for the construction and connecting in functional unity of nuclear reactor/chemical plant/habitat/etc.
So I envision the rovers to represent something like tractors, rather than off-roads. On Mars we need very versatile mobile platform, able to work a a crane, assembly robot for parts heavier than 1 tonne, excavator, carrier or tractor of exploration habs... Like the earth`s construction machines are powered by an engine or two, the Universal mobile Platform could be just wheeled engine + fuel/oxidizer tanks + numerous hubs for attaching: excavation scoops, crane`s hooks, 'hands', hab`s trailers... remotelly controled from the stationary habitat or from the inhabited trailer.

With enough parts, such LEGO-type versatile mobile equipment could comprise impressive fleet able to do everything we`d like in very modest payload-price. A standart container with ~20 tonnes of cargo can host several 'wheeled combustion engines' equipped with all the necesarry parts, attachments, and components for different functions re-self assembly... A simple and robust wheeled convertable robots with very low degree of autonomy.

SpaceNut · 2004-08-19 09:02:12

All the more reason not to get to comfortable with an enclosed evironment without being in a protective suit less helmet but ready to place one on in a moments notice of trouble.

karov · 2004-08-19 13:26:14

I agree. When in Simplest... was discussed the topic about how the astronauts will dress/undress their spacesuits in narrower vehicle, it occured to me that indeed they shouldn`t undress them entirelly. It would be enough to remove the helmets and the gloves, and to plug the suit`s respiration system and others to the rover`s circulation. I don`t think that many day`s rovers journeys are plausible in the first missions.

MarsDog · 2004-08-19 21:09:46

I don`t think that many day`s rovers journeys are plausible in the first missions.

The first concern for the astonauts will be safety. Building a second, nearby, larger, habitat out of Martian materials would also be a step in continued expansion.
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Analogy is a farm or construction site, where small bulldozer, tractor, and bucket loader are useful on a daily basis.
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In 2 years, 1 meter resolution satellite pictures of Mars will be awailable, and all of us can look forward to planning the first Mars base.

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#1 2004-03-29 09:12:51

Re: Combining the Rover and Hab - Go RV'ing!

#2 2004-03-29 12:36:31

Re: Combining the Rover and Hab - Go RV'ing!

#3 2004-03-29 12:39:38

Re: Combining the Rover and Hab - Go RV'ing!

#4 2004-03-29 14:08:52

Re: Combining the Rover and Hab - Go RV'ing!

#5 2004-03-29 14:30:34

Re: Combining the Rover and Hab - Go RV'ing!

#6 2004-03-29 22:48:31

Re: Combining the Rover and Hab - Go RV'ing!

#7 2004-03-30 14:50:57

Re: Combining the Rover and Hab - Go RV'ing!

#8 2004-03-30 14:51:44

Re: Combining the Rover and Hab - Go RV'ing!

#9 2004-03-30 16:51:47

Re: Combining the Rover and Hab - Go RV'ing!

#10 2004-03-30 17:39:38

Re: Combining the Rover and Hab - Go RV'ing!

#11 2004-03-30 18:07:53

Re: Combining the Rover and Hab - Go RV'ing!

#12 2004-04-02 18:50:32

Re: Combining the Rover and Hab - Go RV'ing!

#13 2004-04-03 11:25:26

Re: Combining the Rover and Hab - Go RV'ing!

#14 2004-04-05 09:45:34

Re: Combining the Rover and Hab - Go RV'ing!

#15 2004-04-13 15:47:16

Re: Combining the Rover and Hab - Go RV'ing!

#16 2004-06-22 13:52:53

Re: Combining the Rover and Hab - Go RV'ing!

#17 2004-08-18 03:09:16

Re: Combining the Rover and Hab - Go RV'ing!

#18 2004-08-18 10:48:19

Re: Combining the Rover and Hab - Go RV'ing!

#19 2004-08-18 13:44:27

Re: Combining the Rover and Hab - Go RV'ing!

#20 2004-08-18 14:17:09

Re: Combining the Rover and Hab - Go RV'ing!

#21 2004-08-19 00:58:43

Re: Combining the Rover and Hab - Go RV'ing!

#22 2004-08-19 02:52:55

Re: Combining the Rover and Hab - Go RV'ing!

#23 2004-08-19 09:02:12

Re: Combining the Rover and Hab - Go RV'ing!

#24 2004-08-19 13:26:14

Re: Combining the Rover and Hab - Go RV'ing!

#25 2004-08-19 21:09:46

Re: Combining the Rover and Hab - Go RV'ing!

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