Manned Mars mission to Mars before 2020?

Mech_Engineer

I will try addressing a few of your ideas, but there's a lot to process here...

From what I understand, water is only good at shielding from neutrons and some other high-energy particles (due to its high Hydrogen content, same with polyethylene), but gamma rays and other high energy ionizing radiations pass right through. Basically, you've only adressed one small part of the shielding dilemma.

There is no technology available to produce a powerful magnetic field that can envelop an entire space ship, so "magnetic shielding" is not an option.

Sounds like a very uncomfortable ride. At a radius of 10m and 6rpm, the coriolis accelerations would be very obvious to the crew members when they were in it, causing pretty bad nausea and disorientation. Wikipedia has a good article on artificial gravity where rotating spacecraft are discussed. The article states that rotational speeds of less that 2rpm need to be used to minimize the coriolis forces present. Sounds like you'll need a much large radius of rotation to still achieve Martian-G, let alone Earth-G.

Actually, from what I understand parachute landings are safer and less prone to failure than powered decelerations/landings. Carrying fuel for deceleration and landing is a huge waste when you have an atmosphere at your disposal.

I dont' think 25cm of water will provide much resistance to micrometeroites travelleing at several km/s. Also, as soon as the water is exposed to the vacuum it will sublime away, not form an ice "plug." If the water radiation shield is breached, all of the water will eventually sublime/boil off and vent into space.

Urvabara

http://www.projectrho.com/rocket/rocket3u.html
"However, the data on artificial gravity is a bit out of date. The original research into it had subjects sick at 3 RPM and incapacitated at 6 RPM+. However, more recent research suggests that, by using incremental increases in rotation and making a few limb movements, adaptation can occur with almost no feelings of nausea. The old research (done on about 30 subjects) simply went from zero to full rotation. Moreover, the adaptation can be simultaneous with non- rotational adaptation. So, moving in and out of the rotating habitat for maintenance or whatever is no problem. It's thought that rotation rates of up 7.5 to 10 RPM are possible. This makes Discovery's 5.5m radius centrifuge a real possibility. In fact, with 10 RPM, you could crank it up to a handsome 0.61 G, or 0.34G if you want to play it safe at 7.5RPM."

Astronuc

Somebody has to do criticality tests with U-plasmas first, and based on GCR concepts, there would be problems with seeded H-propellant. There is the little matter of confinment of U-plasma, and the removal of fission projects - out the nozzle with the propellant. Best place to test that is on an asteroid.

D H

Urvabara,

A human mission to Mars in twelve short years must necessarily be a development program rather than a research program. The engineering challenges of stringing together proven technologies to accomplish this goal in such a short time span are incredibly significant. Your last few posts have been on technologies that are far from proven. They are on technologies with very low technology readiness. A string of things, none of which is ready for prime time, makes a very poor basis for making a human mission to Mars in twelve short years.

I suggest you read this wiki description of what NASA and the military call Technology Readiness Level. Over the last several years NASA has come to use this metric quite extensively in its development programs to identify long poles that need extra resources and in its research program to determine where limited research monies are best applied.

Urvabara

Ok. Thank you people.

I would still like to find a solution to the centrifuge problem(s). How to get it on LEO (Low Earth Orbit) with Ares V?

What other problems there are with centrifuges? Consumption of electricity? Too high RPM? The spacecraft starts to wobble when the centrifuge spins?

Still, I wouldn't like to see a manned Mars missions without centrigues. Imagine the crew floating whole the time!

Astronuc

NASA has a priority on Lunar Missions, and manned missions to Mars are effectively over the horizon, unless something changes drastically. Here is the current situation with respect to Lunar missions and Ares I.

This refers to an article in Flight International - Ares I to get extended nozzle lunar variant


See also - http://www.nasa.gov/mission_pages/ex...ain/index.html

Moon, mars and beyond - http://www.nasa.gov/mission_pages/ex...mmb/index.html

Urvabara

You probably agree with me that the real developement of a manned Mars mission should start right away? I do not know if we are ready by 2019, by 2030, by 2037 or by 9999, but I know that we will never get on Mars, if we do not start developing engines, centrifuges, radiation shields, etc. It looks like that they are not even trying to do that. They always just push the mission launch year 30 years to the future. Back in the 1980s, the launch year was 2019, few years ago it was 2030, now it is 2037. Always about 30 years in the future like with the fusion reactors and flying cars.

We (the whole world, not just NASA) should try to push TRLs up one by one in a sensible time frame (30+ years is hardly a sensible time frame). During Apollo program they did a wonderful developement in such a short time frame and with the technology of 1960s! Imagine the computers of 1960s! Now we have computer power to simulate almost anything we want. Computers are developing incredibly fast, why not spacecrafts?

I hate it when they cut NASA's budget. :(

Urvabara

Thanks!

DaveC426913

Certainly all true, except for the returns part. Naturally, the real goal of the mission is to learn how we can safely leave our planet on longer journeys.

I mean, we'll eventually have to do that...

If Louis Bleriot had waited for jet technology, those poor Brits might still be stranded on their island.

Urvabara

http://www.racetomars.ca/mars/marsRising/episode5.jsp
"But recent test results have not been good and designer Leonid Gorshkov at Russia’s Energia Space Corporation has decided parachutes are too risky. The Russians are experimenting with descent engines."

D H

NASA has already started. NASA is going to the Moon by 2020, not Mars. One reason for setting up a long-term base on the Moon is that doing so will address some of the issues associated with going to Mars.

The problem is that NASA's slow-and-steady plan is not what you and the Mars Society want. NASA is being realistic and working within the constraints of a limited budget. Being realistic means you don't base near-term human spaceflight activities on technologies that haven't even gotten off the drawing board. Being realistic means you don't sweep the immense number of issues that we know will be challenges for a human mission to Mars under the rug.

What makes you think they aren't doing those things? Some of those papers you cited were funded by NASA.

There are some things that NASA is not doing. NASA is not looking into nuclear rocket engines for one simple reason: It can't. Nuclear propulsion is not in NASA's budget and has not been for a long time. NASA is not looking at a human mission to Mars for one simple reason: It can't. Congress has explicitly forbidden NASA from doing so for the past three years.

NASA received 10% of the federal budget back in the 1960s. Now it receives about 0.6% of the federal budget.

Urvabara

I have seen some mission plans (2030+) from both ESA and NASA and they do not even mention centrifuges. In the pictures crew members are floating. That is why I assumed they do not even try to develop them.

I also know that both ESA and NASA are going to use chemical rockets. That is why I assumed they do not even try to develop other rocket engine technology. Somewhere I heard that ESA is not going to use nuclear rockets and you said the same about NASA.

Thank you all.

Mech_Engineer

If a planet has an atmosphere, deceleration using parachutes is a weight-efficient method that is arguably "safer" than being dependent on an advanced retro rocket system. It is also lighter to build a double or triple redundant parachute system when compared to a retro rocket system including the fuel requirements (and double or triple redundant makes it heavier still). There is a reason all of the robotic Mars landers up to this point have used parachutes.

LURCH

Ooops! Sorry about that, I voted before reading this reply. To me, the advantage for chemical rockets is that they exist. I prefer the use of exiting systems for spaceflight, because imaginary ones don't actually do anything.

I believe all of the problems of getting to and from Mars with chemical rockets (including gravity and radiation) have already been addressed by the Mars Direct plan.

LowlyPion

As a general observation what is the point of having any time constraint on a goal to go to Mars except perhaps impatience to want to know what's there and to know it now?

In the sixties the race to the moon seemed to be born out of the angst of the Cold War. The idea that the Russians would take over the moon was seen as not a satisfactory strategic option. If they had built bases and then in a military sense been operating from "higher" ground - at least that was the thinking as I recall - then they could have tremendous advantages. Our ability to retaliate if we were there first would have been supreme.

But now we know that the challenges of even getting to Mars and returning are so severe as to honestly wish anyone luck in even doing it - much less so to worry about someone setting up a military option there with any relevance to matters on Earth.

So why the rush? I'd say people will eventually get there and maybe even return and it will surely be an exciting event with a treasure trove of information confirming or expanding our knowledge about a number of things, but I surely see no rush priority on it with so many other more daunting challenges that are so much more relevant to more people than just the thirst for knowledge about the cosmos.

Astronuc

The infrastructure used for the moon mission would be adpated to a manned Mars mission.

Goddard has a program on radiation shielding for astronauts.

There has been a lot of work already done on NTR concepts, and the Russian have done more recent work. Some funding came from NASA and some from DOE.

There are centrifuge concepts, and there are a lot of low budget studies done at various universities.

One might wish to look into the STAIF conferences that have been held in Albuquerque hosted by University of New Mexico, Institute for Space & Nuclear Power Studies, since 1983.


See also - http://www.iaass.org/

Urvabara

Thanks. Good info.