New Mars Forums

I see what you're saying. If that be the case, then all manned mission designs would share this problem.

Surely though, landing a single 24-tonne tonne spacecraft is the equivalent to landing four 6-tonne spacecraft in parallel?

Are there any papers written on the mass-capture capability of the martian atmosphere?

Thanks cIclops. Tell me, do you also happen to know the Trans-Mars mass of the latests Mars Rovers? I want to get an idea of the difference.

How much mass could the Ares V with the Lunar EDS send to a trans-mars trajectory?

Let me summarize my proposal from a different perspective:

First launch window (Testing & Preparation): Cargo vehicles and uncrewed (spare) Hab sent to various sites. These serve as landing beacons for future missions.

Second launch window (Manned Landings): A few crewed Habs are sent to these sites. Previously landed vehicles contain spares, supplies, and science equipment.

Third launch window (Capabilities Expanded): Surface mobilities are enhanced with cargo deliveries of necessary equipment. Small ISRU plants are also tested on the surface.

Fourth launch window (Supply Mission): After having roamed the surface, the mobile habs pick a good location for a temporary base. Additional cargo missions are delivered here for supply of science equipment and re-supply of consumables in order to extend the mission duration.

Fifth launch window (Supply Mission): Again, the mobile hab would have moved on to find another interesting spot. Another cargo vehicle is sent to the site as before.

Sixth launch window (ERV Delivery): The technologies necessary for the ERV would have been thoroughly trialed up until this point (as part of earlier cargo missions). The completed ERV is sent to the location of the Hab as before.

Seventh launch window (Return to Earth): The astronauts, having explored a vast amount of martian terrain, are given the opportunity to return to the Earth. They could either use a two-step approach (a la DRM), with a seperate Ascent and ERV vehicle, or a one-step approach (a la Mars Direct), with a do-it-all ERV.

In the above scenario, the mission duration is about 10 or 12 years, but this depends only on when the ERV is completed. If ERV development is accelerated, a mission duration of only 4 years is possible using this architecture.

What I am talking about is very localised heat pumping. A planetary scale system would be ridiculous and impossible.

But lets side-track from the subject of the topic and talk about actively cooling structures on the surface.

What I can imagine is large dome-type structures (for minimum surface area to volume ratio), lifted off the hot surface by insulating blocks. And I'm talking really big domes, as the more internal volume the better. Perhaps it could house a large internal heat sink, of either water or rock, to help stabilize internal temperatures, and to provide some thermal lag in the event that the active cooling system fails.

The cooling system would simply be a large heat pump, using CO2 as a refigerant. The CO2 would be circulated under the same external pressure as that of the interior of the dome (say 1 to 10 bar).

Fresh CO2 would be leaked in to a sealed compartment, pushing itself through a heat exchanger (on the inside of the dome), thereby cooling the internal heat-sink. The CO2 would then be compressed to slightly above external atmosphere levels, thereby expelling it out of the dome.

It would be a single pass system. No need to recirculate CO2.

Would this work?

Here's what the development schedule might look like:

1. Development of Descent system allows Cargo delivery. First flights are to deliver cargo to a single landing site for future occupation.

2. Development of Life support system allows Habitat. First flights send crew to location of pre-delivered supplies.

3. Development of Mobility system allows Mobile Habitat. Mobility cradle is sent with cargo. Crew bolt it to their habitat to allow long-range mobility.

4. Development of advanced ISRU system allows large scale surface fuel production. By this time, smaller ISRU systems have been tested as part of previous cargo flights.

5. Development of Mars Ascent stage allows Earth Return Vehicle. Again, smaller ascent stages have been tested as part of earlier cargo flights. The full scale ISRU system (with hydrogen feedstock) may be sent seperately to the ERV.

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Perhaps the best part of the MXM architecture is that it allows the more complicated technologies (mobility system, ISRU, ascent stage) to be developed and tested on the martian surface, as part of the cargo deliveries. As the cargo vehicles are delivered accurately to the Hab (thanks to landing beacons, as the mobile Hab should be waiting at a good science spot), these technologies can be tested as part of the crews science objectives.

I like your idea Tom. It's bizzare but ingenious. However, it would require an unimaginatively big planetary-scale effort to construct those plates. And what would happen if it were to rupture while under pressure?

What about actively cooling structures on the surface? Has any thought been given to using the CO2 gas as a refigerant?

Mmm, sounds delectably crunchy.

Sorry cIclops. Sometimes, I can be a bit of a dick. I must have misunderstood your proposal.

Nevertheless, I think that I have made the point that this proposal differs enough from similar previous proposals. The integration of Hab mobility is one key point.

I think your proposal touched on some degree of reliance on base-building. I have the view that base-building should only be attempted after the planet has been thoroughly explored, and a suitably rich location found.

Remember, Mars is a planet, not an island. It is unimaginably vast. With that said, I fear that any foray into pre-mature base building would only pull resources away from the explorers further out.

This plan has been superceded by this plan.

There are two critical ideas which I think I have brought to the table: (1) Hab mobility, and (2) The option to resupply with conventional rockets in case of a problem or cancellation of the HLLV program.

In all likelyhood (2) would never be needed as the HLLV would be unkillable so long as it is required to send the finished ERV. Nevertheless, the ability to deliver payloads on conventional launch vehicles may play a minor support role. Also, the ability to ensure the crews survival for many years despite of HLLV cancellation would make the one-way mission more politically palatable (the alternative being the fate of the crew being tied directly with the HLLV).

While the second point is politically valuable, it is the first point which is much more valuable to the mission architecture itself. A mobile Hab would be essential for long-term sorties (perhaps on the order of 5 to 10 years on the surface), as it would break crew monotony. At the same time, science return may be of orders of magnitude greater. Also, making the Hab mobile would be much safer than relying on long-range rover sorties.

However, having the Hab roam across the surface presents many of its own problems. But with the unique way in which this architecture relies on continued re-supply, the problem is automatically addressed: Cargo vehicles are simply landed nearest to the location of the Hab at that particular point in time. If it is a little, or even a lot out, the mobile Hab simply changes course to suit.

As new parts and tools for repair are sent with each cargo vehicle, the reliability of the Habs mobility systems would be maintained. In the unfortunate event that the mobility system fails unrepairably, the next cargo vehicle can send a replacement system, which by design is capable of transporting itself to the Hab for fitting.

If this fails, there may still be a light rover onboard the Hab which, either manned or remotely operated, can be used to collect the mobility system. If the new mobility system still fails, the crew of the stranded Hab could utilize the rover to collect supplies from the cargo vehicle (as in other architectures) until another cargo vehicle, with another mobility system, is sent. However, there should be enough supplies contained in the Hab itself to last many years.

I can imagine that a (very unlikely) permanent stranding event would serve to accelerate ERV development if it has not been finished already. In any case, the crew would simply wait it out on the surface, being continuosly re-supplied by cargo deliveries, until the ERV arrives.

Yeah, sorry cIclops. The idea of a one-way mission is not new.

What I bring to the table is the idea that a mission plan that begins as a one-way architecture does not necessarily have to end as one.

Perhaps it can be thought of as a Mars Direct mission, but in reverse, where the Hab is developed and sent first, and the more expensive ERV is developed and sent later.