New Mars Forums

louis wrote:

I think over the last few years I have come round to the view that a lot of outside activities can be carried out by robots. We have some incredibly sophisticated robots on Earth now - the only prob. is that they are very expensive, but that isn't really an issue with a multi billion dollar Mars mission.  I think we should restrict to outside activity in space suits for humans to a few days in high summer on Mars when they might be able to wear light mittens with their finger pads exposed...That would be nice, if they could tell us how Mars feels when the temperatures are up to double figures celsius.

Um, wouldnt their blood boil in their capillaries? I think human body temperature is incompatible with such an environment.

Yesterday I attended a seminar given by Don Hassler, the PI for the RAD instrument on MSL. The topic was the radiation flux observed during cruise from Earth to Mars, and what conditions have been like on the Martian surface.

The fairly constant background of Galactic Cosmic Radiation (GCR) dominated the cruise dose, though he pointed out that if you had a big enough solar flare it could have delivered a comparable dose (they did in fact see 5 moderate flares during cruise, but they contributed only ~5% of the total amount of radiation).

Being inside the MSL capsule in cruise provided a significant amount of shielding, comparable to that on the ISS (something on the order of 20g/cm2). About 500 mSv was accumulated during cruise, which would be roughly half an astronaut's typical career allowance. Don mentioned that a manned cruise would be designed to be shorter for than a robotic mission, and pointed out that shielding around sleeping quarters using drinking water/propellant tanks could significantly reduce the amount of radiation received.

On the Martian surface RAD has seen radiation fluxes values ~1/2 of what it did in cruise. This is basically because half the sky is blocked by the planet. The thin Martian atmosphere itself offers a level of protection comparable to the MSL capsule structure.

Once people are there and the transportation system is established, they can create a return capacity. If Falcon stages are designed to soft land back on Earth, they could be soft landed on Mars as well, with some modifications, and then refueled. If they reall manage to land 4 people every 2 years, I wouldn't be surprised if return capacity isn't established in 10 or 12 years.

I've been away from these forums for a few years and see I missed some really good threads. I'd like to reinvigorate this one if others are interested. I am quoting RobS plan here, but I also was paying heed to GW's comments about career-limit radiation and the problems of getting good exploration accomplished.

At this date, we still do not know enough about Mars for a manned mission to achieve what it could achieve. Sure, we have the tech to get ppl to Mars, but we do not yet have the knowledge of Mars itself or experience on Mars to make it work as well as it might. I would like to see the success of Curiosity and Opportunity replicated about 50-100 times over before we send ppl there. The ISS was a global effort. This can be a global effort as well. We can put 100 rovers on Mars for less than $50B. (Versus the price of propping up one failed bank corporation for .... you dont want to know how much!) We should be aiming 20 rovers at Mars at each launch window over the next decade. Let them crawl all over the planet, checking out as much as possible and gathering rocks and samples. Try ballooning over Mars with black sun-inflated balloons. With each Rover payload, send along some iffier proposals to see how they work. Send along too a little bit of infrastructure for the future crewed mission to retrieve and use. Nothing ventured, nothing gained.

When we DO get a manned expedition to Mars, they should go in knowing what to expect and have lots of work laid out for them in advance by the Rovers. Part of their mission should be to visit each of the 100 rovers that got there before them and collect the physical data from them, like rocks and gasses, etc. They should arirve with replacement parts for the Rovers and go in expectation of doing service maintenance on all of them so that the Rovers can continue working for another decade on Mars before the next manned mission arrives. If we can get something to Mars with the crew that's capable of lifting cargo across the Martian surface, by flight, then they could also pick up errant Rovers or dead-ended Rovers and relocate them to new territory -- shuffle our whole deck of 100 up there. We could devise a modular aerodynamic lifter of some kind which could be attached to a Rover, so that it gives the Rover wings and the Rover gives it wheels. Flying over the rough terrain makes the most sense, if we can figure out how.

In short, GW and RobS make me realise just how much more homework there is to do that we havent done yet, but could do without risking human life for a mission which would be more politics and showmanship (flags and footprints) than science.

RobS wrote:

Thank you, GW Johnson, I very much like and agree with your post. I wonder what the implications of it are.

1. How many to send to Mars. I'd favor six, if it is practical, perhaps two ships of three each. If either one had difficulties, the other one could provide for everyone, especially if parts could be salvaged from the incapacitated vehicle. When the International Space Station had only 3 on board it could do very little because it took 2 crew full time to maintain the station! I suspect a Mars base would take one or two as well, so you need a minimum of three and preferably more.

2. Establishing a series of beachheads (one every 26 months) versus establishing a "Martian McMurdo." McMurdo, of course, is the hub of Antarctic operations, and having a well equipped hub has been invaluable for Antarctic exploration (which is about 5% the size of Mars!). I think safety favors a concentration of resources at one point initially, but that also reduces the range of exploration you do at first. A McMurdo can also accumulate habs so that there is a lot of pressurized volume per crewmember.

3. Practical range of a human crew. I refer to their surface vehicles here. Zubrin proposes a pressurized rover with a range of 1,000 kilometers, but I don't think anyone is going 400+ kilometers out and back until Mars has at least two such vehicles and probably has a surface crew of more than six, for safety reasons.

4. Human/robot interaction. If we had five or six telerobotic operated vehicles (TROVs) like a second-generation Spirit and Opportunity or like the Mars Science Lab, a surface crew could supplement a terrestrial crew quite nicely because they could control the vehicles live. If each TROV had a sample bin that could eventually be retrieved, that would be even better. In my Mars novel I envisioned robotic solar powered airplanes called "Sunwings" rather like the Helios that NASA experiemented with a few years back. The astronauts would assemble the pieces of the sunwing and test the vehicles. They could be flown down to a TROV robotically and snag a long mast with a hook. The mast was attached to the sample bin, thereby retrieving the samples and bringing them back to base, where some preliminary analysis could be done. Some samples could be selected for return to earth later. There may be other ways to retrieve samples, too; Zubrin proposed a vehicle with a built in thermal rocket. The solar power on the wings would heat up a beryllium engine and a pump would compress carbon dioxide from the atmosphere. Once the engine was hot and the CO2 tank full, the vehicle would run the CO2 through the hot beryllium engine and fly using the rocket exhaust perhaps 20 or 50 kilometers. It would then perform a rocket landing, examine rocks, recharge its propulsion system, and repeat. A balloon/TROV system might work as well. The idea would be to keep the crew busy inside the base with vital tasks spread out all over Mars.

5. Longer term, exploration expands via a transportation system of some kind. Maybe once there are a dozen people on Mars and considerable experience with vehicles has been accumulated, you send out expeditions to clear a track to an attractive geological site about 500 kilometers away, where you set up a small "oasis" (solar panels, Sabatier reactor, water supply, maybe a well, methane and oxygen tanks, maybe some emergency shelter and supplies). You return to base, process your samples, write up articles for Nature and JGR with a terrestrial support crew, then a few months later you go out with the equipment for a second oasis. You stop at the first oasis to refuel and do a bit a maintenance and set up a second oasis another 500 kilometers out. Perhaps sunwings drop ice blocks wrapped in plastic so you have a water supply at each one. A system like this could gradually develop a network of dirt tracks across the planet. Or perhaps larger sunwings can safely carry people and the expedition equipment can be kept out almost permanently, with crew rotation by air. But exploration strategies like this have to evolve over time as equipment improves. It may be a few people and a lot of robots will be plenty.

Oh, and by the way, in terms of the actual prices of the meteorites:

This article states that the meteorites are going for $11,000/0z-$25,000/oz.  That is equivalent to $388/g-$794/g.  However, please consider the ways in which these samples are special:

• This is only the fifth time which an identified Martian meteorite has been seen falling to Earth, and the first time in the last 50 years

• It was lying on the ground for a period of months, which in this context and especially this location (Morocco, probably in the Sahara) will lead to very little contamination

• The guy who found them has a monopoly on selling martian meteorites of this quality

• There were only 7 kg

If you're importing 2-4 tonnes of the stuff per year, as you have suggested, will the price go down?  Absolutely.  And a hell of a lot, too.  I'm sticking with $10/g-$25/g for Martian meteorites, and of course less in profit.

Well, since that's pretty much what he's been saying... I heard that SpaceX was founded because Musk wanted to put a greenhouse on Mars and wasn't satisfied by the quoted costs...?

Terraformer - It's his money (in part) so he can spend it how he wants. While it might not be the most financially efficient mission, but if it captures the imagination of the world like Apollo, it will be worth every cent, and then some.

GW Johnson - I agree with you about the micro gravity. Yes, it adds complexity, time and fuel. But they will be in space for 500 days, minor issues will quickly become major annoyances. A stressed crew could lead to mission disaster. Yes, people have spent lots of time in freefall, but not while there is a 30 minute communication delay. That's going to add a whole new layer of stress.

I'm also wondering what experiments the crew will take along. Small lander, telescope, sensors etc.

Spending a week and a half in a capsule to go to the moon and back is a feasible thing to do.  About 2 weeks in a capsule was the limit demonstrated by Gemini 7.  That crew was in bad shape by the time they landed.

Going to Mars or Venus is quite another proposition entirely,  as the travel time is measured in years for the round trip.  Some sort of large,  spacious habitat is simply required.  Artificial gravity by spin is simply required medically,  and it makes life support design so much easier (for example,  you can use an ordinary toilet,  and you can cook over an ordinary stove with ordinary pots and pans). 

If you're going to go to all the trouble (and it really is an enormous amount of trouble to mount such a mission!) to send men all the way to Mars and back,  the small additional burden of adding a lander to the mission seems quite stupid to ignore.  Why go all that way and not land?  Landing is THE emotional imperative,  and has been since the invention of the telescope. 

Guys,  I made a small breakthrough.  I got sidetracked from looking at Mars missions:  I looked at small spaceplanes from LEO,  re the cheap access problem.  I found a way to use a low density ceramic composite as a non-ablative fully-reusable heat shield.  I found a way to balance convective entry heating against skin temperature in a configuration that could be built,  and stay below the solid phase-change temperature limitation for the material.  For LEO,  this is restricted to low ballistic coefficients of small spaceplanes entering belly-first,  with folded wings to avoid non-survivable airloads at 90 degree angle-of-attack attitudes.

The heating environment for Mars entry,  especially from LMO,  is a whole lot easier.  The same heat shield material should work there on capsule-shaped craft with far higher ballistic coefficients.  The "reusable Mars ferry" or "reusable landing boat" dream is indeed feasible.  This material is only a little bit denser than styrofoam.  No more heavy ablative heat shields.

I,  too,  noticed it's been a bit quiet here on the forums.

Hi Midoshi,  long time no see.

GW