# Manned mission to Mars

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1. Jul 19, 2012

### baconman71

What locations on Mars would be good for a first manned mission? This is remembering that we want to 1. survive out there and 2. be able to look for possible signs of life and do other science (study geology and the atmosphere).

2. Jul 19, 2012

### Drakkith

Staff Emeritus
I'm not sure. Other than the terrain being favorable for landing and exploring, I don't know what other criteria there might be. Anyone else have any ideas?

3. Jul 19, 2012

### drbanner

If finding evidence of life is the primary objective, then I would think one of the lava tubes/cave formations would have to be at the top of the list. If life is to be found on Mars, it will most likely be underground away from the radiation, and where moisture/water might be present. A cave/lava tube would offer both opportunities. Check out the cave that some 7th graders discovered for NASA:

A complete understanding of the geothermal gradient on Mars will aid in the quest as well. Wouldn't have to go to deep to get into the 'liquid water phase'. Here is a good link:

www.lpi.usra.edu/meetings/geomars2001/pdf/7044.pdf

I would be more surprised to find a planet/moon ‘sterile’ in ‘habitable areas' where liquid moisture/water exists. Sterility might not be the norm, but rather the exception? Time will tell.

4. Jul 19, 2012

### drbanner

Forgot to mention that the cave would also provide protection to the Astronauts from the radiation as well. Communication equipment could be left outside the cave. Not sure I would want to be the first to step into an unexplored cave on another planet? These will be brave men/women who venture there for the 1st time to say the least.

5. Jul 19, 2012

### phinds

I am strongly of the opinion that the best location for a manned Mars mission is nowhere, at least anytime in the next decade or three. It's a suicide mission plain and simple with anything like today's technology.

6. Jul 19, 2012

### drbanner

I would have to partly agree. All about the amount of resources and time we would want to put invest into it. We pulled off Apollo missions that we were damn lucky to have succeeded with the technology at hand back then. Not without tragedy and loss of life however.

I think the resources could certainly be better served with separate robotic missions with no loss of life vs. the manned mission, but somewhere along the line a Politician will make it his/her agenda to make him/her self remembered for something.

Certainly there are Pro's to a manned mission. Not easy to explore a cave with a rover, and rovers cannot entirely 'fix themselves' out on the mission, as the Astronauts could adjust and overcome some obstacles they will encounter. There most certainly will be obstacles on the way, some of which may be deadly.

7. Jul 19, 2012

### DaveC426913

I would expect that survival and signs of life would both warrant a landing near one of the polar ice caps. Mostly CO2 but lots of H2O in there too.

8. Jul 20, 2012

### Ryan_m_b

Staff Emeritus
From my armchair the best option would seem to be Phobos. Dig in for shelter against radiation and teleoperate equipment on the surface. Far easier to get back from as well.

9. Jul 21, 2012

### Chronos

I'm solidly in favor of probes to research such things. Sending people is prohibitvely expensive. Finding life on mars [past or present] would be a wonderful discovery, but, the expense of a manned mission is unjustified.

10. Jul 21, 2012

### Ryan_m_b

Staff Emeritus
Agreed. The extra money it would take for a manned mission could probably go further if it was invested in robotics.

11. Jul 21, 2012

### DaveC426913

But it's more than just a research project. It is the next most likely place where humans are eventually going to live (in a century or so).

12. Jul 21, 2012

### Staff: Mentor

Better to set up a permanent colony on the moon than a temporary visit to mars, IMO. Or even a self sufficient base in earth orbit. The only reason to send humans to space is to learn how to live there.

13. Jul 22, 2012

### rorix_bw

I disagree with those 2 premises. Private sector space flight is here already, but hasn't reached Mars yet. What makes you think a national science mission project will be first to land? If Mars Corp gets there first, maybe they will pick sites with tourist or commerical interest?

14. Jul 22, 2012

### Staff: Mentor

If (when? ;)) a manned mission to mars costs ~10 billions at some point in the future (corrected for inflation), chances are good that a scientific mission is started. It would probably involve several months of research on Mars, due to orbital mechanics, require a lot of training of the astronauts, have a high risk of failure and probably some significant radiation exposition, even with shielding.
While I cannot exclude it, I doubt that a touristic mission can get that amount of money under those conditions.

15. Jul 22, 2012

### rorix_bw

The cost of space missions is going to drop sharply once there is orbital infrastructure. So much power and thrust is needed to escape earth vs starting from a space station in orbit.

16. Jul 22, 2012

Staff Emeritus
This whole question seems to be a solution in search of a problem.

Since cost was mentioned, we really need to take a serious look at it. Spirit and Opportunity cost about $500,000/kg to make it to the Martian surface. The lunar module ascent stage weighed about 2000 kg without propellent. So that's a billion dollars right off the bat. The LM had about 4.5 habitable cubic meters for two people. You can't put people in a space that small for 450 days, so let's say that the astronauts share a space the size of a Supermax Prison cell. That increases the volume by 4.2, and assuming the mass goes as area, the cost by 2.6. So we're at 2.6 billion. The reliability of mars missions is about 2/3, and manned missions is >95%. A good rule of thumb is that reducing the failure rate by x requires an increase in cost by x. If you're willing to go with a 90% success rate, that gets you to$8.7B. So that's a guess what it costs to drop two guys in a tin can on the surface of Mars.

The problem is that you can't just drop two guys in a tin can on the surface. You need to send a rocket so they can get back. A Delta II weighs about 200,000 kilograms, so you're talking hundreds of billions.

17. Jul 22, 2012

### Astronuc

Staff Emeritus
And don't forget radiation protection for the round trip, as well as on orbit, as well as on surface. How long will the trip be? 90 days each of two ways - or 200 or 300 or . . . .

Don't forget also, that we haven't yet launched anything from the surface of Mars.

The big challenge would be to get the launch vehicle and it's propellant onto Mars - intact. That's not trivial - considering how the Rovers (and they are small) were landed.

Aerobraking is not much of an option in the Martian atmosphere.

One would probably want some sort of station (e.g., Skylab or ISS) on orbit around Mars to serve as an intermediate point to and from the surface. An Earth-to-Mars transfer vehicle would rendezvous with the station. The return Mars-to-Earth would be parked there waiting for the return trip.

Radiation protection from solar wind (high energy protons, deutrons and alpha particles) as well as GCR must be addressed. One issue is the spallation reactions in the structural materials of the space craft - and the secondary radiation this prodcues. Low Z elements like H and Li in the form of LiH (or H in ice or frozen ammonia) provide good shield against neutrons and protons. Higher Z materials provide effective shielding against gamma radiation and X-rays.

These issues have been on the table for the last several decades or so.

Last edited: Jul 22, 2012
18. Jul 22, 2012

### Staff: Mentor

Barely. There has been exactly one commercial spaceflight (not counting Virgin). They have a long way to go to catch up.

19. Jul 22, 2012

### D H

Staff Emeritus
While there has been only one private venture that docked with the International Space Station, there have been dozens and dozens of commercial space flights. The communications satellite industry is a private industry in the US and in other countries. Those private communications satellites are put into orbit by private launch companies.

20. Jul 22, 2012

### Staff: Mentor

Moon escape velocity is 2,4km/s, mars escape velocity is 5,0km/s. An orbit is 1/sqrt(2) of this value. This has to be delivered by chemical rockets, sure. From orbit, 1-1/sqrt(2) (~1.4km/s) deltav is required to reach escape velocity, and 0.9km/s more to reach a Hohmann transfer orbit.
An ion drive with 1N thrust can accelerate 10 tons of mass to +2.3km/s within 9 months. Actually the ion drives would require a bit more delta-v, as they cannot be used like conventional rockets (short burn to change orbits). Obviously too much, but we are just off by a factor of ~10. As ion drives have exhaust velocities of several 10 km/s, the fraction reaction mass / total mass is small (<10%) and this system (together with everything else not needed on the surface) can stay in mars orbit all the time.