Problems with Humans on Mars

cIclops · 2008-04-28 07:30:09

Space Show interview with Dennis Bushnell - Chief scientist at NASA Langley Research Center - 27 Apr 2008

During the interview Bushnell poured several buckets of cold water onto Human Mars missions as well as human spaceflight generally.

With current technology he said this about Humans on Mars:

what is safe is not affordable and what is affordable is not safe

He then highlighted these major problems for people on the surface of Mars:

micro gravity
galactic space radiation
systems reliability
toxicity of Martian dust (hexavalent chromium)

Bushnell said the technology to do it affordably and safely needs about 10-15 years of work followed by 10-15 years of development, so Human missions are about 30-35 years out.

He added that humans on mars has competition from the rapid developments in virtual reality (VR). He sees Nano sensors on Mars streaming back high speed data with optical links to enable "five senses" VR that is "better than real" - all with a cost factor 500 - 1000 less than putting people on Mars.

Bushnell's solution: use VR and robots until Mars is terraformed and suitable for humans.

Gregori · 2008-04-28 13:14:13

good find.

Can they even do nano bots though?

cIclops · 2008-04-28 13:52:01

Nano sensors. It wouldn't be necessary to make nano bots. The smaller the rover/lander is the more of them can be landed for the same cost. Nano sensors would give each platform far more sensors in more wavelengths, using less power.

Gregori · 2008-04-28 14:18:27

Nano sensors. It wouldn't be necessary to make nano bots. The smaller the rover/lander is the more of them can be landed for the same cost. Nano sensors would give each platform far more sensors in more wavelengths, using less power.

mkay, wasn't paying too much attention

Didn't know about the hexavalent chromium either.

GCNRevenger · 2008-04-28 18:14:36

*Cough* Chief scientist? As in, the people who say "forget sending man, lets just send robots!" A pox be upon him!

louis · 2008-04-28 18:54:03

What's this guys problem?

Let's take each of those in turn.

- Micro gravity

I'm not sure I would describe 38% gravity as microgravity. People have survived well on the ISS for more than a year in zero G.

- Galactic space radiation

Come on! This has been discussed ad nauseam here. There is no major problem with this on Mars. People aren't going to be running around in their underwear on the surface. Entrenched inflatables coveredin regolith will provide near-complete protection and the radiation on the surface is often overestimated.

- Systems reliability

Well yes, but that's what NASA is there for.

Think of all those successful Apollo missions. THAT is systems reliability.

- Toxicity of Martian dust (hexavalent chromium)

This is pathetic. Human beings operate in all sorts of toxic environments on earth. Why do we lose the ability to do so when we reach Mars? from Wikipedia: "Workers in many different occupations are exposed to hexavalent chromium."

cIclops · 2008-04-29 00:00:32

louis, let's look at this guy's problems ...

Micro gravity won't be a problem during transit to Mars as ISS has proven. Counter measures are improving all the time and may be sufficient to enable astronauts to work quickly after landing. Recently Yuri Malenchenko walked off a plane a few hours after 192 days in zero gravity. Arriving in a 0.38g Martian field should be much easier.

The effects of staying on Mars for 15 months in 0.38g are almost completely unknown, however the 6 months stays at the Lunar Outpost in 0.17g should go a long way to understanding if this is a problem or not.

Bushnell didn't mention that the return transit may be the most problematic of all, arriving in a 1g field with high deceleration will be quite a stress on astronauts who have spent 15 months in 0.38g and then 6 months in 0g.

Galactic space radiation can certainly be reduced by shielding both inspace and on Mars. Recent NASA studies have almost doubled the safe exposure time for astronauts to space radiation as the effects seem to have been overestimated. Bushnell talks about accelerator experiments showing serious effects, presumably on human cells or animal studies. Anyone know about these?

Systems reliability is obviously important, critical systems simply have to function throughout the whole 2.5 year mission. This is not beyond current technology. Getting the mass low enough may be a problem, but yes surely it's doable well within 30 years.

Toxicity of Martian dust Bushnell gave the answer himself, astronauts will need to work dust free. Again quite doable.

Surprisingly there was one problem that he didn't mention considering that Langley and his background are specialized in aeronautics, and that is the problem of landing large mass packages on Mars. Perhaps this isn't such a hard problem after all.

Tom Kalbfus · 2008-04-29 12:20:09

As for the toxicity of martian dust, simply don't bring the dust into the habs, at least not the same parts where the astronauts live. The way to do this is to treat the space suits as one-man spaceships that use legs for propulsive power. You dock the space suits to the hab, and the astronaut climbs out through the backpack and into the hab. There needs to be a method of cleaning the mars suits from the outside. Perhaps compressed martian air will do the trick. A pressure hose can blow the martian dust off the suits, and especially off the backpacks so that a seal with the habs docking port can be established.

The technology will be used on the Moon before it gets to Mars, the principle is the same.

GCNRevenger · 2008-04-29 14:22:05

I'm thinking a combination of compressed Martian air with electrostatic removal, and perhaps even a water shower for the suit.

This non-potable water would be recycled through a grating in the floor and filtered out, and could serve as an emergency backup water supply.

Its not that big of a deal.

RobertDyck · 2008-04-29 15:01:55

You know that's one reason I like the Mechanical Counter Pressure suit. It's machine washable.

Build a mud room (EVA prep room) between the airlock and the rest of the hab. Give it a fan like a washroom fan, but with a really good air filter to remove dust; filtered air blowing back into the hab. Give the EVA prep room negative pressure relative to the hab when the fan is turned on, so air is sucked into the EVA prep room from the rest of the hab when the door is open. I thought of using a HEPA filter because it does remove particles the size of Mars fines, but that would be the last stage of a multi-filter system before the air re-enters the hab. You could use a normal furnace filter type thing, but you want the first stage of the filter to be something that can be cleaned easily and often. One local Mars Society member suggested bubbling air from the EVA prep room through a tank of water. That would dissolve dust and fines in the water. He thought you could dump the dirty water when finished, I think water will be too precious to do that; but you could evaporate the water, perhaps vacuum dehydrate the water leaving dry dirt. Dump the dirt outside.

Get creative with the filters. It's not a big deal.

RobertDyck · 2008-04-29 15:19:46

Galactic radiation: did you know the worst form of radiation is heavy ion radiation? It has a nasty tendency to split into multiple particles on impact with radiation shielding, each smaller and slower but causing more cell hits. So light radiation shielding is actually worse than no radiation shielding. Well, for heavy ion radiation, for proton or light ion radiation any shielding is good. The good news is Mars atmosphere is the best shielding for heavy ions. Over 90% is blocked, as long as you pick a landing location at or below the datum. If you pick a landing location 2km below the datum, such as the low lands in the north, then 99% of heavy ion radiation is blocked. We can block X-rays with metal, alpha can be blocked by a single sheet of aluminum foil, beta with a single sheet of paper or plastic, and UV can be blocked by anything opaque or spectrally selective coatings that NASA already uses on windows. Let's see, that leaves gamma, proton, and light ion radiation. These forms are best blocked by sandbags filled with Mars regolith. So just pile sandbags on your hab roof and you're done.

Source of Mars radiation data: 4 papers published by the Marie instrument team for the Mars Odyssey orbiter. I kept a copy of each paper in PDF format. I could list citations if you want.

I did some calculations with the help of a nuclear engineering student from MIT. We found that you can keep annual radiation exposure to within limits for a nuclear reactor worker in the US if you limit time outdoors in a spacesuit to 40 hours per week. The airlock would have sand bags on it's roof so time there doesn't count, but a greenhouse would not have sandbags so even though it's a shirt-sleeve environment time in the greenhouse would count. But a maximum of 40 hours per week is a work week. How many astronauts would complain about that? The rest of their time can be in-doors in the lab.

Conclusion: the safest place in our solar system next to the Earth, is the surface of Mars.

louis · 2008-04-29 15:33:47

Yes I'm glad to see the positive response here.

Couple of points. Re dust control I've already suggested we "carpet" the base area. The "carpeted" surface can then be vacuumed on a 24 hour basis by robots (technology already exists - will need to be cold-proofed like Mars robots). We could also build windbreaks around the base area.

But of course the main dust control will be simply avoiding going outside. There won't be a great need to be outside on the surface apart from raw materials gathering (but that need only take a few days at the start of the mission.

The main reason to venture outside will be psychological I feel. People will want to go outside and it will help them remain balanced psychologically.

louis · 2008-04-29 15:37:25

Sorry - one other point I meant to mention...

I think there could be a role for an LEO artificial gravity station. On return from a Mars mission the crew would enter this station and gradually be returned to one G before re-entry to earth.

cIclops · 2008-04-29 16:34:59

Dust: apparently there are new fabrics that repel dust using coatings and or electrostatics?

Radiation:

From: Space Radiation and Exploration (PDF) - 27 Feb 2008

louis · 2008-04-29 17:17:37

Another more prosaic approach to dust control and space suits: ultrathin disposable plastic overalls. In fact I think this might be the most practical way forward.

RobertDyck · 2008-04-29 19:53:32

Another more prosaic approach to dust control and space suits: ultrathin disposable plastic overalls. In fact I think this might be the most practical way forward.

Think reusable, not disposable. We won't have mass budget to take a lot of expendables along.

In fact, to remove CO2 use silver oxide grannuals. Grannuals are compatible with microwave regeneration. Heat the grannuals to drive CO2 out; the silver oxide is indefinately reusable. There are thermally regenerable sorbents for organics as well, that means scrubbing bad smells.

For power use lithium ion batteries. Saft already makes space rated lithium ion batteries; they don't list cycle life for their space rated batteries, but their terrestrial lithium ion batteries last 1500 to 1600 charge/discharge cycles depending on how much end-of-life capacity you find acceptable. Long life requires maintaining stable battery temperature, they make a big deal of radiator capacity being less than other battery chemistries. Even if you got 500 charge/discharge cycles, one battery pack per suit would give each suit one EVA per sol for every sol during a 16.5 month surface stay. That's more than enough.

cIclops · 2008-04-30 02:51:43

Newsflash today Andrews Space Wins NASA Exploration Contract

Seattle, WA, April 29, 2008 - Andrews Space, Inc. (Andrews) announced today that it has signed a contract with the National Aeronautics and Space Administration (NASA) to analyze design solutions related to NASA’s Vision for Space Exploration. The specific efforts are focused on the Mars Entry, Descent, and Landing technologies and techniques.
Under NASA Langley Research Center’s Entry, Descent, and Landing (EDL) research area, Andrews will perform trade studies related to High Mass Mars Entry Systems (HMMES), from identifying Mars surface elements that need to be packaged, to the physical constraints imposed by the launch system, and to the entry dispersions that the guidance, navigation, and control systems must overcome to provide a safe delivery to the chosen landing site. The primary thrust of the study is to identify the technical risks with respect to future EDL systems and recommend near term technology development activities to reduce those risks to acceptable levels.

So good to see NASA starting to work on these problems, another small step for missions to Mars!

EuroLauncher · 2008-04-30 07:44:20

I don't see why this would be exclusively a Mars problem and going to the Moon or trucking around LEO in circles will solve these issues

micro gravity

Mars G = 1/3 of E while Moon gravity is one-sixth

galactic space radiation

Very same problem on the Moon

systems reliability

A non-issue for me ? How can you say something is unreliable if its never been flown. All we have to go on are the reliability of Apollo, Skylab, Shuttle, ISS etc and the figures for some Russian missions

toxicity of Martian dust (hexavalent chromium)

Lunar dust is also toxic, heck even coal mines on Earth are toxic but that doesn't stop people working there. Mars should be about human colonizations, if only send robots for these next few decades I think humans will have failed too evolve and we might be better off accepting androids as our new leaders like the scifi stories.

cIclops · 2008-04-30 08:15:54

Yep. Exploring and living on the Moon has many of same serious problems as Mars, this is why NASA are going there first.

GCR is more intense on the Lunar surface as there is no atmosphere at all, however, sometimes it is protected inside the Earth's magnetotail. Gravity is only half Mars, so if there are issues from this they are expected to be more visible. Systems reliability is less critical on the Moon as astronauts can return to Earth within a few days, whereas on Mars it could take almost two years.

There's proven reliability and estimated reliability. We know from ISS history that some systems are unreliable so a lot of work has to be done to improve them, for example O2 generation. No life support system has yet functioned reliably for the time it will take to complete a Mars mission.

If Martian dust proves to be toxic, and this hasn't been proven yet, then it will have to be dealt with before people can live there. People don't live in mines.

Exploration is the very first step before even a base can be established, and a base will be needed to establish a colony.

Gregori · 2008-04-30 17:11:28

I'm actually much more down with what this guys is saying.

We've learned far more about space with robotic probes than anything we learned from manned missions.

Before we send humans to Mars, I think we should have extensively explored the planet first, probably with lots of sophiscitated robotic probes and maybe even VR. We know relatively little about this planet and the possible dangers humans face on it. It still a young field of research. They find something new and completely unexpected about this planet every couple of months!

If even one death occurred on a Mars mission, that could end up stopping the whole program - we'd be back where we started.

Mars isn't going anywhere, so patience won't do us any harm.

The pace at which this technology is developing is going to lap aerospace technology - several times over.

The next piece of infrastructure we put over Mars should be a satelite that vastly increases the amount of Data that can be transmitted from probes on the red planet. I believe there was a Mars 'Internet' Satelite that was being planned but got scrapped.

Manned missions and human colonization of space won't become cheap until we've developed a ground breaking propulsion technology like Fusion Power or a durable SSTO. It just far too fucking expensive.

I know we all want to go to Mars (and I'm a firm advocate of manned space exploration) but a bit of rationality and realism is needed.

Marsman · 2008-04-30 20:30:45

I will be appearing on The Space Show myself on May 23rd so I need
to be careful what I say here but the first question which pops up
with Dennis is "Is there any political or career biased opinions in
there?" He gets paid by NASA and so far their message on human Mars
programs has been a fairly uniform 20 to 30 years away sort of talk.
I agree with his points about technical problems but to me those
don't seem to be the real problem for humans to Mars. Lack of
political will is the problem. If people wanted to go to Mars they
would commit to doing so and even if took 100 years they would work
through the problems until it happened. Unfortunately this is simply
not the case. Sometimes research is done, most times it isn't. Until
there is a firm committment by someone to go to Mars we will
continue to have to rely upon the odd study done here and there,
lots of opinions and circular reasoning as usual.

These problems, real or not, can be overcome given enough time,
research and dollars. We are not trying to invent time travel here.
Humans went to the Moon did they not? They dealt with dust and
radiation there, did they not? Humans have lived in microgravity for
extended periods have they not? Humans have survived microgravity
have they not? Humans even live in space for extended periods and
I'm sure there are systems on the ISS that have lasted more than 3
years, proving that at least some technologies can last the
distance.

Mars enthusiasts often get accused of "ignoring the issues" or
downplaying their importance but I can't agree with that. Everywhere
I go in the Mars community ALL of these problems(and more) are being
discussed in depth. Some are even working on solutions such as the
human factors studies that the Mars Society conducts at their
analogue stations, the studies of the Mars Institute, Mars Foundation or our own mission design studies.

As to his comments on waiting for terraforming before humans go- Add
1000 years or more. Plus does he understand the economics of this?
Terraforming is not a process that can be 100% robotic either. There
will need to be at least some humans living there to work it.
Ultimately, we either go to Mars or we don't. No one is denying the
problems here. What we are saying is let's work on finding solutions
to those problems, something NASA, despite their great achievements
to date, are not always doing.

cIclops · 2008-05-01 02:11:59

I'm actually much more down with what this guys is saying.
We've learned far more about space with robotic probes than anything we learned from manned missions.
Before we send humans to Mars, I think we should have extensively explored the planet first, probably with lots of sophiscitated robotic probes and maybe even VR. We know relatively little about this planet and the possible dangers humans face on it. It still a young field of research. They find something new and completely unexpected about this planet every couple of months!
If even one death occurred on a Mars mission, that could end up stopping the whole program - we'd be back where we started.
Mars isn't going anywhere, so patience won't do us any harm.

The atmosphere, the undersea world and the poles of the Earth didn't go anywhere either, yet people explored them. Would we have been better off waiting patiently rather than exploring them?

It's obvious that more has been learned about space by robots than manned missions. The same is not true about the surface of the Moon, for equally obvious reasons. To fully characterize space a whole range of instruments is needed, most of which extend human senses in wavelength and sensitivity. Human presence adds something completely different to exploration, not only for the explorers themselves but for those that merely observe their experiences and hear their stories. Learning about space needs both robots and people, just as learning about Earth.

Of course there are places that it makes little sense for people to explore because of the danger and cost, but as technology advances there are less and less of these places. Today people can and do visit almost every part of Earth, sometimes just for fun, whereas 100 years ago there were many places impossible to reach. Not everybody wants to do this, but many do. Just as we explored the surface of the Earth and under it's surface, new places are discovered, places even more difficult to reach. First robots are sent, then people want to follow.

Sure, exploring Mars is going to be dangerous and difficult - that's two good reasons why some people want to do it!

Bushnell looks at the problems and says: it's too difficult, let's not even try. Some of us look at the same problems and say: let's solve them and get on with it!

cIclops · 2008-05-01 02:46:53

I will be appearing on The Space Show myself on May 23rd so I need
to be careful what I say here but the first question which pops up
with Dennis is "Is there any political or career biased opinions in
there?" He gets paid by NASA and so far their message on human Mars
programs has been a fairly uniform 20 to 30 years away sort of talk.
I agree with his points about technical problems but to me those
don't seem to be the real problem for humans to Mars. Lack of
political will is the problem. If people wanted to go to Mars they
would commit to doing so and even if took 100 years they would work
through the problems until it happened. Unfortunately this is simply
not the case. Sometimes research is done, most times it isn't. Until
there is a firm committment by someone to go to Mars we will
continue to have to rely upon the odd study done here and there,
lots of opinions and circular reasoning as usual.
These problems, real or not, can be overcome given enough time,
research and dollars. We are not trying to invent time travel here.
Humans went to the Moon did they not? They dealt with dust and
radiation there, did they not? Humans have lived in microgravity for
extended periods have they not? Humans have survived microgravity
have they not? Humans even live in space for extended periods and
I'm sure there are systems on the ISS that have lasted more than 3
years, proving that at least some technologies can last the
distance.
Mars enthusiasts often get accused of "ignoring the issues" or
downplaying their importance but I can't agree with that. Everywhere
I go in the Mars community ALL of these problems(and more) are being
discussed in depth. Some are even working on solutions such as the
human factors studies that the Mars Society conducts at their
analogue stations, the studies of the Mars Institute, Mars Foundation or our own mission design studies.

Congratulations on receiving an invite to the show! Rather than launch an ad hom attack on Bushnell, it would be better to simply deal with his list of valid problems. Yes, political will is an important factor as it determines the level of funding made available for solving these hard problems. Unfortunately some problems are so hard they require more than just money - they require breakthroughs in science and technology.

Mike Griffin seems to think along the same timescale of about 30 years, but he has said it can be quicker with more funding. As my signature says, tripling NASA's funding should be enough and a lot cheaper than Hawkin's recent appeal for a ten fold increase in spending. Just developing Ares V and Altair in parallel with Ares I would save years, then starting work on the Mars vehicles and surface systems right now would pull the whole schedule closer. How soon it can be done is hard to say, Zubrin's ten years does seem very optimistic but not impossible. Imagine a Mars program in parallel with the Lunar one and a full science program too, now that might be enough to even get Obama excited Setting tough goals drives invention and solutions, if it takes longer then so be it, physics can't be fooled!

A few weeks before Bushnell, Donald Rapp was also interviewed on the Space Show, his list of problems was even longer, yet he was far more optimistic about solving them. He speaks well and the interview is well worth a listen.

Rapp stressed that the time to reach Mars is an order magnitude longer transit than to reach the Moon. Specifically, that the 2.5 year mission duration means a huge difference in:

mass of consumables
reliability of life support systems
zero gravity time
radiation exposure
habitat volume
propulsion requirements

and he also mentioned these problems:

aero assisted landing of large payloads
few abort options
no short sorties to prove out systems
26 month launch windows limits rescue missions

The lists overlap, but of course all these problems need to be addressed.

SpaceNut · 2008-05-01 03:55:00

I think that we already have the data for Mars Cosmic radiation exposure and from it land in the areas that are dark blue and we are fine.

http://www.space.com/scienceastronomy/s … 20308.html

http://www.spaceref.com/news/viewpr.html?pid=7584

03.01.02.Fig.4_marie_br.jpg

Commodore · 2008-05-01 08:18:50

I think that we already have the data for Mars Cosmic radiation exposure and from it land in the areas that are dark blue and we are fine.
http://www.space.com/scienceastronomy/s … 20308.html
http://www.spaceref.com/news/viewpr.html?pid=7584

The higher the altitude, the less atmosphere, the less protection.

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