How radiation rules Mars exploration

Feb 13, 2014 by Sheyna E. Gifford
Radiation dose equivalent chart comparing Martian mission radiation to levels those experienced on Earth. Credit: JPL

Nearly everything we know about the radiation exposure on a trip to Mars we have learned in the past 200 days.

For much longer, we have known that space is a risky place to be, radiation being one of many reasons. We believed that once our explorers safely landed on Mars' surface, the planet would provide shielding from the ravages of radiation. We didn't how much, or how little, until very recently. Radiation and its variations impact not only the planning of human and robotic missions, but also the search for life taking place right now.

The first-ever radiation readings from the surface of another planet were published last month in Science Express. The take-home lesson, as well as the getting-there lesson and the staying-there lesson, is this: don't forget to pack your shielding.

"Radiation is the one environmental characteristics that we don't have a lot of experience with on Earth because we're protected by our magnetosphere and relatively thick atmosphere. But it's a daily fact of life on Mars," said Don Hassler, the principle investigator on the paper, "Mars' Surface Radiation Environment Measured with the Mars Science Laboratory's Curiosity Rover."

On Earth, we often associate with fallout from catastrophes such as Chernobyl and Fukushima. We sometimes worry over CAT scans, chest x-rays or transcontinental flights. However, according to the Health Physics Society, the biggest source of radiation for most of us, by far, is inhaled radon, which comes from the natural decay of material present since the Earth's formation,

In open space, human beings continuously contend with intense solar and . Solar Energy Particles (SEPs) and Galactic Cosmic Rays (GCRs) turn a trip to Mars into a six-month radiation shower.

The Mars rover Curiosity has allowed us to finally calculate an average dose over the 180-day journey. It is approximately 300 mSv, the equivalent of 24 CAT scans. In just getting to Mars, an explorer would be exposed to more than 15 times an annual radiation limit for a worker in a nuclear power plant.

Data from Curiosity also demonstrated that landing only partially solves the problem. Once on the Martian surface, cosmic radiation coming from the far side of the planet is blocked. This cuts down detected GCRs by half. The protection from strong solar particles, though, is shoddy and inconsistent. Substantial variations in SEPs occur as the meager Martian atmosphere is tussled by solar wind.

Radiation and its variations impact not only the planning of human and robotic missions, but also the search for extraterrestrial life. Without a substantial atmospheric protection, powerful particles entering the air can penetrate straight into the Martian soil. On impacting the surface, the GCRs and SEPs from space produce cascades of other energetic particles. Of these newly produced particles, gamma rays and neutrons are easily capable of breaking molecular bonds in the soil, destroying evidence of past life, as well as any life that may be presenting trying to survive there.

The Mars' Surface Radiation paper estimates that finding intact organic molecules means digging deeper, down a meter or so. In addition to digging deeper, we need to dig for newer evidence, near impact sites where the rock has spent less time exposed to the elements.

"Radiation is probably the key parameter in determining how much alteration organics are experiencing in the rocks on the surface,"said Jennifer Eigenbrode from Goddard Institute of Space Studies, and an author of the paper. "If we find organics on , the circumstance in which we find them [the context of the rocks], the history of the rocks, and the chemistry that we find, will help guide our mission strategy."

Radiation detected by Curiosity has given us a better guide on how and where to look for former or current life. Future life, specifically the lives of our astronauts, also hinges upon these radiation measurements.

"Fundamentally "situational awareness is the strategy we have to use going forward," Hassler said. "We can design shelters on the surface to protect the astronauts."

Deep space, the place of greatest exposure, remains an issue.

"Perhaps one of the areas they would be most vulnerable would be during a spacewalk [on the way] to Mars."

In transit and on the planet, surviving space means predicting . Space weather forecasting is a relatively new field, but one that's proving to be critical to all space missions.

Space weather involves forecasting solar flares, coronal mass ejections, and geo-magnetic storms. These highly energetic events emanate from the sun. When they cross the orbit of a planet, the same SEPs attacking organics can spell disaster for satellites, space stations, astronauts and the communication systems they all depend upon.

Radiation Assessment Detector. Photo of RAD flight model in the lab (left) and artwork of an older MSL rover design, showing RAD charged particle channel 65-degree field-of-view pointing towards the zenith. Credit: JPL

"To protect our satellites is becoming more and more important here on Earth," Hassler said.

Protecting satellites and people around Earth and Mars likely involves setting up two separate systems. Using Earth-based technologies to predict the radiation levels on Mars isn't the best choice. The distance and opposition of the planets compounds the problem. When Mars is on the far side of the sun, it isn't even an option.

"When we send astronauts to Mars, we will have to do our own space weather monitoring from [Mars]," said Hassler.

From beneath the shelter of Earth's ample atmosphere, we continue to receive daily updates from Curiosity. Its 3-pound Radiation Assessment Detector (RAD) informs us about surface radiation events, particle type and relative frequencies. For now, RAD is the only way that we can study Martian radiation and make plans for the future.

In the future, what we've learned from RAD will be used to better look for life on the surface, to design suits and habitats, to plan extravehicular activities. Because of what we have learned, we can begin to establish weather prediction systems. We can tell explorers that there is an increased risk of cancer associated with a trip to Mars (approximately 5 percent over a lifetime).

In these ways, rules the past, present and future of effective planetary exploration. Thanks to RAD measurements and the resulting analysis, we can begin to write a survival guide for life on Mars.

Explore further: SDO captures images of two mid-level flares

More information: "Mars' Surface Radiation Environment Measured with the Mars Science Laboratory's Curiosity Rover." Donald M. Hassler, Cary Zeitlin, Robert F. Wimmer-Schweingruber, Bent Ehresmann, Scot Rafkin, Jennifer L. Eigenbrode, David E. Brinza, Gerald Weigle, Stephan Böttcher, Eckart Böhm, Soenke Burmeister, Jingnan Guo, Jan Köhler, Cesar Martin, Guenther Reitz, Francis A. Cucinotta, Myung-Hee Kim, David Grinspoon, Mark A. Bullock, Arik Posner, Javier Gómez-Elvira, Ashwin Vasavada, John P. Grotzinger, and MSL Science Team. Science 24 January 2014: 343 (6169), 1244797. Published online 9 December 2013 [DOI: 10.1126/science.1244797]

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User comments : 32

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freeiam
3.5 / 5 (4) Feb 13, 2014
It's relatively straight forward to generate a magnetic field and reduce solar radiation to zero.
This can be done on transit and on Mars.
Strange this isn't mentioned.
Torbjorn_Larsson_OM
5 / 5 (4) Feb 13, 2014
Ironically the 5 % increased cancer risk is half of the increased risk (IIRC) that people accept en masse when they move into cities (mostly from particles getting into your lungs). As most everyone does, implying the claim "take a Mars trip for your health" isn't far off. =D

@freeiam: It isn't easy at all, it would mass a lot and require a massive [sic!] power source that no one knows how to build.

And it would only shield from solar wind and CME. The bulk of the trans-lunar radiation is now known to be cosmic rays. You need a meter of rock (or a dense atmosphere) to shield from that: "The Mars' Surface Radiation paper estimates that finding intact organic molecules means digging deeper, down a meter or so."
Urgelt
4.5 / 5 (2) Feb 13, 2014
"@freeiam: It isn't easy at all, it would mass a lot and require a massive [sic!] power source that no one knows how to build."

Could be. But I'll point out that Lockheed Martin's Skunk Works has announced that they are developing a trailer-sized 100 MW commercial nuclear fusion power generator. They haven't told us much about it yet, but they project that by 2022, they'll be able to market them, and by 2017, they'll have a working commercial prototype. That's small enough and powerful enough to get a spacecraft from Earth to Mars in a month, and powerful enough to generate magnetic shields at the same time.

Eh, maybe it won't pan out. Don't know yet.
Urgelt
4 / 5 (2) Feb 13, 2014
From the thrust of the article, it would seem to me that if we are serious about putting boots on Mars, we'd better use robots to build tunnel habitats for them before they get there. And infrastructure - volatiles mining and separation, power, etc.
Firefly Mal
3 / 5 (2) Feb 14, 2014
Reading the comments thus far is like listening to virgins talking about sex. An as yet un-invented magnetic anti-radiation field? Such fields are currently science fiction.

Cosmic rays and solar storms contain charged particles, mostly protons. Charged particles can create "Bremsstrahlung" or braking radiation. Particle shielding is generally something with lots of hydrogen in it, like water, liquid hydrogen propellant tanks, lithium hydride, paraffin or a hydrogenated polyethylene composite. Carbon's decent (better than aluminum or steel, worse than hydrogen or hydrocarbon plastics) against neutrons and cosmic rays and has the useful secondary property of not becoming radioactive when bombarded with such particles.

The article is a good argument for nuclear propulsion – six month transit times are out of the question.

Nuclear pulse propulsion is the best option – the General Atomics reference design specific impulses in the range of 6,000 seconds, or about thirteen times that of the Space Shuttle Main Engine. With refinements a theoretical maximum of 100,000 seconds (1 MN•s/kg) might be possible. Thrusts were in the millions of tons, allowing spacecraft larger than 8 × 10^6 tons to be built with 1958 materials. The reference design had a takeoff weight of several thousand tons and was to carry supplies and equipment for a crew of 200 for a six month surface mission. There is your payload capability sufficient for even the heaviest radiation shielding. This low-tech single-stage reference design would reach Mars and back in four weeks from the Earth's surface (compared to 12 months for NASA's current chemically powered reference mission). The same craft could visit Saturn's moons in a seven-month mission (compared to chemically powered missions of about nine years).
antialias_physorg
not rated yet Feb 14, 2014
Just to put this into perspective: an equivalent does of 1000mS translates into a 5.5% chance of developing fatal cancer (at some point).

So forget those inflateable habitats on Mars. If you want to survive for an appreciable amount of time: dig in

Ironically the 5 % increased cancer risk is half of the increased risk (IIRC) that people accept en masse when they move into cities (mostly from particles getting into your lungs).

Increasing your risk by that much over a lifetime is a bit different than increasing your risk by that over a year - every year - in terms of what one might think is acceptable.
TheGhostofOtto1923
3 / 5 (2) Feb 14, 2014
Could be. But I'll point out that Lockheed Martin's Skunk Works has announced that they are developing a trailer-sized 100 MW commercial nuclear fusion power generator
Along with outrageous nonsense you should always include your outrageous source. Oh lookee here it is:

"The high beta fusion reactor (also known as the 4th generation prototype T4) is a project being developed by a team led by Charles Chase of Lockheed Martin's Skunk Works. The "high beta" configuration allows a compact fusion reactor design and speedier development timeline (5 years instead of 30)... The company hopes to have a prototype working by 2017, scale it up to a full production model by 2022 and to be able to meet global baseload energy demand by 2050."

Perhaps they will develop a meta material which will work with higher-energy radiation.
GSwift7
5 / 5 (1) Feb 17, 2014
This means that human missions to Mars of length greater than 6 months on the ground are not likely within the next 20 years. Short trips are reasonable since there are plenty of people willing to face the risks.

Since our present landing capacity on Mars is very limited, it just doesn't seem practical to talk about any kind of reactor the size of a shipping container in the near future, or any realistic heavy equipment to dig and build burried shelters.

When thinking about burried shelters, keep in mind how the rocks have been making holes in the wheels of Curiosity. I can't imagine dumping regolith with those rocks mixed in it on top of a shelter, so you'd need to filter all those out or crush them down small. Either way, that kind of equipment isn't trivial to operate, much less operating it remotely with robotic equipment.

This article says radiation might be the highest barrier for human exploration, but I think power supply might be a bigger problem, at least for now.
TheGhostofOtto1923
1 / 5 (2) Feb 17, 2014
When thinking about burried shelters, keep in mind how the rocks have been making holes in the wheels of Curiosity. I can't imagine dumping regolith with those rocks mixed in it on top of a shelter
The wheels were poorly designed. This is how we learn. Rocks just as sharp exist here on earth with its stronger gravity, and construction and military equipment have no problem with them.
This article says radiation might be the highest barrier for human exploration, but I think power supply might be a bigger problem
Why? We have kilotons of fissiles which were created for the purpose.
GSwift7
5 / 5 (1) Feb 18, 2014
Rocks just as sharp exist here on earth with its stronger gravity, and construction and military equipment have no problem with them


I think you'll find that the wheels, tracks, axles, bearings, etc. on earthly heavy equipment would exceed the weight limit for landing on Mars, even without the rest of the vehicle. And good luck assembling a vehicle delivered in pieces to Mars, since our ability to land two packages near one another on Mars is sketchy at best, and something like Curiosity (in size an weight) would need to do the assembly work.

As for power supplies, mainly the same problem as heavy equipment; weight. I see a system called DEER that is modular and transportable, but it's total weight is 13 metric tons. Maybe a Mars variation of the design could be much lighter. With ambient radiation already high, shielding can be reduced, for example.

continued:
GSwift7
5 / 5 (2) Feb 18, 2014
Providing power on Mars is a really tricky business. Our current landing weight max is around 2000 lbs, so let's say we can double that in 20 years (inflatable heat shield, etc). That's still a tough limit to beat.

Obviously RTG's are the go-to choice initially, but you've got to have something more robust for the long term, like in the range of 5-10 MW, at least.

There's no way solar is gonna work on Mars. Keeping them clean would be prohibitive and you would need a big back-up system in case a dust storm blocks the sun for a few months.

I agree that nuclear of some type is the only way, but there's a ton of hurdles in the way of that. Most of the hurdles are self-imposed, but that doesn't help to eliminate them. The environmental groups aren't going to let you launch a nuclear reactor easily, for example. Even if you cut all the red tape, you've got to completely re-design the system for space travel and for Mars (how do you cool a steam generator without air pressure?)
TheGhostofOtto1923
1 / 5 (1) Feb 18, 2014
I think you'll find that the wheels, tracks, axles, bearings, etc. on earthly heavy equipment would exceed the weight limit for landing on Mars
Thats a silly thing to say. I think you'll find that engineers are capable of designing their equipt to land whatever they need to land on mars or anywhere else. The next rovers will be bigger, more capable, and have better-designed wheels.
our ability to land two packages near one another on Mars is sketchy at best
Where did you get this? How would you know what NASA engineers believe they can and cannot do?
and something like Curiosity (in size an weight) would need to do the assembly work
And why are you talking about assembly? These were incidentally concerns with the ISS and that worked out fine didn't it?
There's no way solar is gonna work on Mars. Keeping them clean
Past rovers used solar and they have worked spectacularly. Again, engrs will design whatever they need, to work however they want.
TheGhostofOtto1923
1 / 5 (1) Feb 18, 2014
The environmental groups aren't going to let you launch a nuclear reactor easily
Youre only demonstrating what you don't know. The Russians have been using reactors in space for decades - 30 of them to be exact. The US has used one.
http://en.wikiped...iki/US-A

-But we have used RTGs in space since 1961.

"Curiosity's RTG is fueled by 4.8 kg (11 lb) of plutonium-238 dioxide supplied by the U.S. Department of Energy. "
Even if you cut all the red tape, you've got to completely re-design the system for space travel and for Mars (how do you cool a steam generator without air pressure?)
... See how you embarrass yourself?
Our current landing weight max is around 2000 lbs
Again, where do you get this stuff? Curiosity was designed to land this weight. That does not imply a limit.
no fate
not rated yet Feb 18, 2014
Human biological systems cannot survive a mission of this tenure away from the earth's gravity and magnetic field. The various issues experienced by the crew of the ISS after 6 month tour in a fairly low earth orbit are nothing in comparison to the issues stemming from the complete absence of either one. Even with extensive daily excercise the atrophy rate for the musculo-skeletal system is rediculously high. The most delicate systems are the most effected (sensory systems, nerves).

Every cell in our bodies, every function, is adapted to life here and the various forces which continuously act upon us, down to the atomic level. Without these forces, our body gradually loses the ability for it's internal systems to communicate with each other. Cells cannot replicate properly, nerve impulses behave eradically.

Shielding from radiation is just the start. To be successful on a trip this long all of the earths systems our bodies require must be replicated.
TheGhostofOtto1923
1 / 5 (1) Feb 18, 2014
Engineers at work:

"The Orbital Piloted Assembly and Experiment Complex... is a proposed third-generation modular space station in Low Earth orbit. OPSEK would initially consist of modules from the Russian Orbital Segment of the International Space Station (ISS).

"The proposal would use OPSEK to assemble components of manned interplanetary spacecraft destined for Mars, the Moon, and possibly Saturn. The returning crew would also recover on the station before landing on Earth. This Russian space station could form part of a deep-space network, supporting manned exploration of the Solar system."

-This will enable the assembly and launch of, among other things, mars landers of virtually unlimited size.
TheGhostofOtto1923
1 / 5 (1) Feb 18, 2014
Every cell in our bodies, every function, is adapted to life here and the various forces which continuously act upon us, down to the atomic level. Without these forces, our body gradually loses the ability for it's internal systems to communicate with each other. Cells cannot replicate properly, nerve impulses behave eradically
This is unwarranted extrapolation based on early experimental results. You have no idea if conditions can be overcome, because scientists don't know yet.

If pending propulsion systems play out, transit time to mars may be as little as 2 months.
http://www.forbes...-rocket/
GSwift7
5 / 5 (2) Feb 18, 2014
Thats a silly thing to say. I think you'll find that engineers are capable of designing their equipt to land whatever they need


No, not really, unless you've broken off into comic book land AGAIN, and you're talking about future-tech from some time in the unforseeable future. This article is talking about missions we can plan and research for in the near future, and the risks associated with them. If you invent a space elevator and go build one on Mars, be sure to let NASA know. Otherwise, landing something heavy on Mars isn't really an option. Nobody has even worked out how such a lander might be built, or whether we have materials that could handle the job. Anybody can draw pictures of space ships, but engineering a structure that would actually withstand the loads is another story. Stopping a heavy load in the Martian atmosphere is not a trivial task. Not enough air breaking until you're really close, then the deceleration is enormous in a short time, or you hit the ground.
no fate
5 / 5 (1) Feb 18, 2014
"This is unwarranted extrapolation based on early experimental results. You have no idea if conditions can be overcome, because scientists don't know yet."

This is based on the fact that we evolved on and live on a planet that has quantifiable forces which effect all components that sum to make a living organism. Muscles do not atrophy when used unless there a seperate condition is causing it. Neurogenic atrophy IMO is the likely culprit.

http://en.wikiped..._atrophy

Vision changes due to changes to the optic nerve

http://www.nasa.g...ges.html

Elevated Norepinephrine - the body's natural response to decreased neural activity, increase the transport mechanism (you can read the whole thing or skip down to the section "expected results")

http://www.spacer...pid=8161

This abstract is from 2005, they had it figured out

http://www.ncbi.n...16101470

Cont...
GSwift7
5 / 5 (1) Feb 18, 2014
our ability to land two packages near one another on Mars is sketchy at best Where did you get this?


Curiosity's landing elipse is the best yet, and it was 12 miles by 4.3 miles diameter. Since we are assuming doubling our max weight, let's assume halving the landing elipse to 6 x 2. I don't think you'd risk hitting one with the other, so landing sites would be chose outside the radius of anything already on the ground. That places new equipment as much as 6 miles away. Curiosity actually landed on the far side of it's landing zone, almost at the worst possible location in relation to the mountain.

Unless they design some revolutionary landing system, the accuracy of the landing zone gets bigger with more weight, so getting heavy landings within a few miles of eachother is wishful thinking.

Heck, it was a miracle that Curiosity even made it down in one piece. I dare you to try that multiple times.
no fate
5 / 5 (1) Feb 18, 2014
Neurons operate via a resting membrane potential of -70mv (internal)regulated by Ion transport.

http://people.eku...tes2.htm

Yes it is just a theory, but I believe this mechanism is effected by the absence of earthbound forces. It is the one thing that could cause the variety of symptoms observed in astronauts. I cannot find anything online nor do any people I know have NASA studies of the effects of time in space on this mechanism, so yes Otto it is extrapolation...but researched in enough depth that I wouldn't say unwarranted.
GSwift7
5 / 5 (2) Feb 18, 2014
This will enable the assembly and launch of, among other things, mars landers of virtually unlimited size.


Yeah, in your comic book fantasy world, but not in the NASA budget world. I almost laughed coffee out my nose when I read your post.

You're so fond of looking stuff up with google, so why don't you do a little reading about how and why it's so hard to land anything on Mars?

It doesn't matter how big you can build something in LEO or in Mars orbit. Materials have physical limits, such as melting point, shear limit and tensile strength. You cannot just slow a 20 ton spacecraft from mach 10 to landing speed in a couple minutes without some serious structural integrity, a heat sheild that doesn't exist yet and a parachute that doesn't exist yet either. You would kill or at least injure any people on board your crazy death trap ship from the g-forces as well.
TheGhostofOtto1923
1 / 5 (1) Feb 18, 2014
This article is talking about missions we can plan and research for in the near future, and the risks associated with them. If you invent a space elevator
The Orbital Piloted Assembly and Experiment Complex... is a proposed third-generation modular space station in Low Earth orbit, is not a space elevator. It is based on existing tech and will, as I say, sending missions of virtually unlimited size to mars.

And VASIMR engines are being installed on the ISS.

"Company officials gave details about a plan to flight-validate another VASIMR variant, the VF-200, on the International Space Station (ISS) in the next few years."
Otherwise, landing something heavy on Mars isn't really an option
No, its more like something which will be happening TOMORROW.

The Orbital Piloted Assembly and Experiment Complex will begin assembling these next-gen craft by the end of the decade.
http://en.wikiped..._Complex
TheGhostofOtto1923
1 / 5 (1) Feb 18, 2014
coffee out my nose when I read your post
-Yeah while your posts fly out the other end. READ THE LINK. NASA is not the only game in town. But it too will be flying asteroid missions by the end of the decade.
You cannot just slow a 20 ton spacecraft from mach 10 to landing speed in a couple minutes without some serious blahblahhhh
-And you have absolutely no appreciation of what engineers are capable of, despite the marvelous things they have accomplished in recent years. The skycrane concept is less than a decade old.

What engrs are working on...
"Supersonic Retro-Propulsion for Future Mars Entry, Descent, and Landing Systems
Recent studies have concluded that Viking-era entry system tech... must be succeeded by new methods capable of delivering large payloads (> 10 metric tons) required for human exploration of Mars. One such tech... Supersonic Retro-Propulsion, has been proposed as an enabling deceleration technique...SUB_SCALE FLIGHT TESTS at Earth by 2016."
TheGhostofOtto1923
1 / 5 (1) Feb 18, 2014
"NASA's long-term Mars human exploration goals will require significant entry system improvements beyond MSL: at least an order of magnitude increase in payload mass (10s of metric tons), four orders of magnitude improvement in landing accuracy (meters), and the capability to land at higher altitudes to reach scientifically interesting sites.

"The EDL-SA team completed a parametric SRP sizing and performance
analysis to estimate mass fraction and thrust requirements for a 40 TON PAYLOAD. The propulsion system baseline for the EDL-SA study was derived from DRA5 and adjusted to satisfy mission objectives:
• Six liquid oxygen, liquid methane (LO2/LCH4) engines, each delivering a maximum thrust of 300 kN
• Engines capable of throttling down to 20% of full thrust
• Two propellant tanks each for the LO2 (8.2 m3 per tank) and LCH4 (6.1 m3 per tank)"

-READ THE LINK and admit your lack of education.
http://www.ssdl.g...5046.pdf
TheGhostofOtto1923
1 / 5 (1) Feb 18, 2014
See the difference between you and me g is that youre content to make judgements based on things you learned years ago whereas I read about things being proposed by the space agencies and assume that they are based on hard engineering studies and preliminary designs which I can probably find on the net.

And so I look, and I find them.

"SUB_SCALE FLIGHT TESTS at Earth by 2016"

"40 TON PAYLOAD"

"Engines capable of throttling down to 20% of full thrust"

"four orders of magnitude improvement in landing accuracy (meters)"

"assemble components of manned interplanetary spacecraft destined for Mars, the Moon, and possibly Saturn"

-These arent comic book parameters g. They are NASA design parameters which they and the other agencies fully expect to meet within the next decade.
GSwift7
5 / 5 (2) Feb 19, 2014
Yeah while your posts fly out the other end. READ THE LINK. NASA is not the only game in town


lol, that was a good one. You go ahead and ride a Russian rocket to Mars. I think I'll wait for a NASA rocket that will actually make it there in one piece. Yeah, when it comes to Mars, NASA is really the only game in town with enough experience to do a manned mission.

And you have absolutely no appreciation of what engineers are capable of


Although I don't work in that field, I did attend Auburn for aerospace engineering. My brother attended Embry Riddle, also for aerospace engineering. So yeah, I'm fairly well aware of the technical limitations. See, that's the difference between you and I. You're willing to believe all the hype the nut-jobs and dreamers throw out on the web, while I'm actually looking at nuts and bolts in the real world.
GSwift7
5 / 5 (1) Feb 19, 2014
READ THE LINK and admit your lack of education


Once again, I'm well aware of that analysis, and the dismay it caused due to how far away from that we are today. SLS, Orion and JWST all together do not equal the budget needed for the kind of Mars mission you're talking about. Yeah, they did a feasibility study and some quick envelope math, but we still actually have to figure out if it's possible to do all that stuff. Landing accuracy down to meters, for example, sounds great, but how? Another tough one is a bigger heat shield. You didn't mention it in your quotes, but they'll need a much bigger heat shield for >10 ton landings (btw, I've seen other NASA estimates that placed the landing weight at more like 20 tons, or more). They are working on some of these problems, such as the attempts to make an inflatable heat shield, but stopping 10 tons with current tech is like stopping a freight train by dragging your feet under it.
GSwift7
5 / 5 (1) Feb 19, 2014
Anyway, you've really taken us far off topic and you're not going to start being reasonable any time soon.

I'll repeat my original point, and call it a day. This article suggests that radiation is the biggest barrier to a manned Mars mission, but I think there are actually larger problems, and that power supply is the biggest one. Feel free to disagree, but the nasa analysis of what it would take to put people on Mars that you quoted is a good example of why radiation is far from the hardest problem to solve. Anyway, it doesn't matter what I say. If the article had said the opposite and I was disagreeing with it, you would be arguing the other way. You remind me of the Monty Python skit where the guy wants to purchase an argument.
TheGhostofOtto1923
1 / 5 (1) Feb 19, 2014
Although I don't work in that field, I did attend Auburn for aerospace engineering. My brother attended Embry Riddle, also for aerospace engineering.
Huh. Then it's an even bigger mystery why you have absolutely no appreciation of what engineers are capable of. For instance you are willing to state
NASA is really the only game in town with enough experience to do a manned mission
-and yet you're willing to dismiss

"The SRP development roadmap presented here is framed around the advancement of all necessary component technologies and an integrated system using NASA guidelines for measuring technology maturation."

-with a projected maturation of 10 years (same as the skycrane) as
some quick envelope math... comic book fantasy world... landing something heavy on Mars isn't really an option. Nobody has even worked out how such a lander might be built
As I say, no appreciation. You were so sure this was impossible that you didn't even bother to look.

Pretty sad g.
TheGhostofOtto1923
1 / 5 (1) Feb 19, 2014
Anyway, you've really taken us far off topic
Dude, you're the one who likes to spout ancillary nonsense to impress. Like
doesn 't seem practical to talk about any kind of reactor the size of a shipping container
-or:
any realistic heavy equipment to dig and build burried shelters
-or:
how the rocks have been making holes in the wheels of Curiosity
-or:
power supply might be a bigger problem
-you know? Countering this crap takes a lot of work. If you don't want the thread to stray then stop posting this off-topic crap.
TheGhostofOtto1923
1 / 5 (1) Feb 20, 2014
Landing accuracy down to meters, for example, sounds great, but how?
By the by, just for the record, spacex and others participated on the 2005 X Prize and lunar lander challenge.
http://youtu.be/ZxKWh7kLDzw
http://youtu.be/qRFsGhti_D8

"...require teams to demonstrate control of their vehicle by flying to an altitude of more than 50 meters (160 ft), flying laterally for 100 m (330 ft), and landing on a pad. "

"Grasshopper can land on Earth with the accuracy of a helicopter and has made seven tests ... August 13, 2013, the Grasshopper vehicle successfully completed a "divert test", flying to 250 meters altitude, completing a 100 meter lateral maneuver, and then returning to land on the pad."

Spacex falcon 9
"first stage booster would do a deceleration burn to slow it down and then a second burn just before it reached the water. When all of the over-water testing is complete, they intend to fly back to the launch site and land propulsively, perhaps as early as 2014."
TheGhostofOtto1923
1 / 5 (1) Feb 20, 2014
And the military has been doing this for a very long time. In addition to hovering rocket decoys for the navy, there's this:
http://youtu.be/1wOJ9JImlRs

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