My good friend Steve Stone sent this thoughtful reply, below, to my last week’s column on NASA. It’s fascinating stuff, especially about space radiation. — Quin
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In response to your NASA Needs A Star article, I offer you a few thoughts.
While I believe NASA’s viability depends on purification of mission, re-definition of strategic objectives, and a complete realignment of its facility/site function allocations, the visionary aspects that should drive down into the agency should not come from its administrator. NASA is a national strategic asset. Its mission should be defined by the President, with the main input being from the NSC.
I read an article in the 4 December Mobile Press-Register regarding a 2014 report on space travel that cited 9 factors that make travel even to Mars impractical One problem they haven’t overcome has to do with cosmic radiation. The most damaging appears to be some kind of Iron ion that is especially destructive because of the size of the particle. In the report it likened the particle impact (I suspect it to be a comparison with something like a gamma or beta particle) to being hit by a baseball. This is hinted at on the NASA main website page where they discuss space effects on the human body. The two paragraphs that follow are directly excerpted from Section 4 of that page:
“Space Radiation. The most dangerous aspect of traveling to Mars is space radiation. On the space station, astronauts receive over ten times the radiation than what’s naturally occurring on Earth. Our planet’s magnetic field and atmosphere protect us from harsh cosmic radiation, but without that, you are more exposed to the treacherous radiation. Above Earth’s protective shielding, radiation exposure may increase your cancer risk. It can damage your central nervous system, with both acute effects and later consequences, manifesting itself as altered cognitive function, reduced motor function, and behavioral changes. Space radiation can also cause radiation sickness that results in nausea, vomiting, anorexia, and fatigue. You could develop degenerative tissue diseases such as cataracts, cardiac, and circulatory diseases. The food you eat and the medicine you take must be safe and retain their nutrient and pharmaceutical value, even while being bombarded with space radiation. A vehicle traveling to Mars and a habitat on Mars will need significant protective shielding, which is nonetheless futile against some types of space radiation.
The Key: The space station sits just within Earth’s protective magnetic field, so while our astronauts are exposed to ten times higher the radiation than on Earth, it’s still much less than the radiation a mission to Mars will encounter, and of a different type. Shielding, monitoring, and operational procedures control the radiation risks to acceptable levels to keep you safe. To learn what happens above low Earth orbit, NASA has extensively used ground research facilities to study how radiation affects biological systems, and more importantly, how to protect them. They are developing unique ways to monitor and measure how radiation affects you while living in space, and to identify biological countermeasures. Finally, methods to optimize shielding are being studied to help protect us on a journey to Mars.”
The NASA discussion is very light on details or categorization of the problems. The problem of radiation shielding is enormous. Lightweight shielding, such as borated polyethylene, does protect against large particles like neutrons and possibly the Iron ion, but would require a very thick surround of the stuff. Its only advantage is light weight compared to water, lead or steel. Lead is best, but . . . heavy. Water is good because it’s cheap and easy, but for the same protective ability, it’s also heavy. A water shield for the same radiation strength would have to be as much as 16 times the thickness of lead. The “altered” cognitive function mentioned above would more accurately be stated as “reduced.” The levels of radiation exposure experienced during a trip to Mars, which would take around 9 months each way, would create degeneration of cognitive function so serious all who made the trip would come home in a permanently demented state. Note that cancer concerns are mentioned first, for good reason.
One other problem that’s also discussed on the same page, but isn’t in detail enough for one to understand involves spinal fluids. Normally, due to gravity, spinal fluid circulates within the spinal column. In a weightless environment, instead of circulating, it tends to pool at the base of the brain, putting pressure on the cerebellum, with the potential of permanent brain damage. It’s interesting that the NASA discussion of “The Key” to resolution of this problem doesn’t mention artificial gravities. In our science fiction we see space stations rotating to create an artificial gravity. While that may work with a space station that’s greater than 300 feet in diameter, it becomes increasingly problematic as the diameter shrinks. The smaller the diameter, the faster a vehicle would have to spin. It’s just not practical in mission-sized space vehicles.
NASA needs to reprioritize to focus on fundamental research to overcome the plethora of known problems of space travel. They need to figure out how to make vehicles travel in space at least 10X faster than we’ve ever achieved, cope with the deteriorating effects of weightlessness, and figure out how to achieve practical radiation shielding. Even if we solve the velocity issues and make travel and make a Mars expedition doable, unless the zero gravity and radiation shielding problems are resolved anything farther is impossible.
When I look at all the known problems in space travel I don’t see where a visionary is needed in the agency. I see the qualification requirements for a competent agency head to be experience in large scale administration and finance. In fact, I would think someone like the head of Kellogg-Brown & Root’s logistics operation might be an excellent and effective NASA administrator.
I agree there’s a lot of work to be done at NASA, but the first step should be to realize the practical aspects of what it can and should be doing. Manned space travel is currently the least valuable contribution NASA can make to our society.
Regards, my friend,
Steve
