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On May 11, the critical design review of the NASA Space Launch System (SLS) kicked off in Huntsville, Alabama.
This new rocket will be the most powerful launch vehicle ever built. It is designed to be sustainable and evolve to carry crew and cargo on deep space missions, including an asteroid and ultimately to Mars.
Milestone reviews like the critical design review are just that -- critical. The critical design review demonstrates that the SLS design meets all system requirements with acceptable risk, and accomplishes that within cost and schedule constraints. It also proves that the rocket should continue with full-scale production, assembly, integration, and testing and that the program is ready to begin the next major review covering design certification.
In the critical design review, there are literally thousands of pages of documentation that are reviewed and every part of the system is put under the design microscope by the best minds and engineers at NASA and their contractors. According to the article, all the subsystems have already been gone over in their own critical design reviews, but this one is for the complete project.
This review follows the somewhat more exciting successful booster tests from early March and the first Orion flight test from last December.
(Score: 3, Interesting) by MichaelDavidCrawford on Thursday May 14 2015, @04:25AM
Consider that in 1978, I was appalled to learn that the Delta had proven to be the most-reliable rocket, at one failure out of thirty.
It's not hard to test a small subsystem, but it's harder to test an assembly made out of two subsystems. It gets harder and harder as you scale up.
NASA's first take on the Lunar Lander for Apollo was twice as heavy as the maximum weight they could lift to the moon, so they conducted a "Super Weight Reduction Program", even to the point of removing some of the layers of aluminized mylar insulation to the bare minimum required.
We're not really going to know whether a Mars mission is actually going to work until the astronauts have returned, hopefully alive.
For a while I was puzzling over ways to magnetically shield from charged particles during the Mars mission, but just the other day I learned of the problem of neutron damage to the brain. Neutrons are not magnetic you see. Maybe a beryllium shield, it absorbs neutrons.
In any case, a significant obstacle to the Mars mission, is not the rocket but the radiation shielding.
Yes I Have No Bananas. [gofundme.com]
(Score: 2) by Covalent on Thursday May 14 2015, @01:23PM
You raise excellent points. The problem of radiation shielding is one of the weakest points in a manned mission to Mars. Even the Apollo astronauts could SEE the radiation when they closed their eyes (http://science.nasa.gov/science-news/science-at-nasa/2004/22oct_cataracts/). Further, the astronauts developed eye problems at a greater rate than the general public.
They were outside of the protection of Earth's magnetic field and atmosphere for under 2 weeks. The minimum duration of a manned trip to Mars is mostly likely several years. Even an orbital mission (which might be a precursor to landing) would take 6 months or more.
Both of these lengths of time are likely to significantly shorten the lifespan of your astronauts. I'm no expert, but "dead heroes bad, live heroes good" seems like a no brainer.
That's where the asteroid redirect mission comes into play. http://www.nasa.gov/mission_pages/asteroids/initiative/index.html [nasa.gov]
One of the obvious uses of such an asteroid is AS a spaceship. Why lift all of that mass into orbit if you can use a giant hunk of iron/nickel that just happens to be handy. If you partially hollow out a tiny asteroid, you've essentially got a Faraday Cage that also absorbs neutrons pretty well. Yes it's massive, but it's better than radiation poisoning...
You can't rationally argue somebody out of a position they didn't rationally get into.
(Score: 2) by MichaelDavidCrawford on Thursday May 14 2015, @02:53PM
... that she carried a gram of it around in her pocket, so she could demonstrate to others, that you can see the radiation with your eyes shut.
She and Pierre both died of Leukemia twenty years later after they isolated it. I visited her crypt at the Paris Pantheon in November, 1997.
Sometimes, thinking about Marie Curie, makes me scream.
Yes I Have No Bananas. [gofundme.com]
(Score: 2) by Yog-Yogguth on Sunday May 17 2015, @01:08PM
I thought so too before looking it up at Wikipedia some years ago; it seems Pierre died from the wheel of a horse-drawn carriage crushing his skull etc. after he slipped (wet cobblestones, leaves, or horse manure?) while crossing a street (filled with traffic I suppose).
But he wasn't in great health so maybe if he hadn't died in an accident.
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(Score: 2) by MichaelDavidCrawford on Thursday May 14 2015, @02:56PM
There is a great deal of spaceflight history that, while well-documented, can be hard to find. In my case I know a lot about it because I once lived in an Air Force town. The Solano County Library in Fairfield, California has an excellent collection of spaceflight history books, such as "We Seven" by the Mercury astronauts.
I expect "The Right Stuff" was based on "We Seven".
Yes I Have No Bananas. [gofundme.com]
(Score: 2) by hubie on Thursday May 14 2015, @05:13PM
Particle shielding can be a tricky business because you need to tailor your shielding to the characteristics of the particles you care about. For instance, you generally don't need to worry about neutrons flying around in space because free neutrons have a half-life of only like 12 minutes before they decay to a proton, electron and electron antineutrino. However, if you're not careful, you could design your shielding such that a high energy proton comes in, strikes your shielding, and kicks off secondary products (like neutrons) that come out the back side of your shield and rattle around your living quarters (this is essentially how a neutron monitor [udel.edu] works, except that it is using the atmosphere as the "shield" to generate secondary products).
There are all sorts of fun and interesting technical problems that come up when talking about shielding for long duration space missions, which is why it is not an easy topic to ignore. It is also why I remain pessimistic when it comes to the feasibility of this topic, at least for the foreseeable near-term.