A Radioactive Astronaut-Hopeful (Space update)

20 11 2010

Me probing an old military well in the Nevada wilderness for geologic data.

By education and trade, I’m a geologist, having worked now in the professional world for more than six years getting my boots dirty performing hydrogeology, water resources, drilling, geomorphology research, and environmental contaminant transport and remediation work in some of the most remote territory this country has to offer.  However, in my push toward becoming an astronaut, one may wonder why I suddenly think it’s a good idea to be working as a radiological engineer and pursuing graduate work in Radiation Health Physics (in addition to my Space Studies work at UND).

Why not study something more direct, like Planetary Geology (Astrogeology)?

The answer, while seemingly obscure, is simple:  What does geology, outer space, the Moon’s surface, Mars’s surface, and advanced spacecraft power and propulsion systems all have in common?  Radioactivity.

Boltwoodite and Torbernite, uranium-bearing mineral samples. (Credit: Ben McGee)

On Earth, (and other heavy rocky bodies,) radioactivity is a natural occurrence.  Plants (and even human beings) all beam out radioactive gamma rays from a natural isotope of Potassium.  (This is prevalent enough that you can calibrate your instruments to it in the wild.)  Even more to the point, radioactive Uranium and Thorium are more common in the Earth’s crust than Gold or Silver.  These elements are crucial to determining the ages of rocks.

Now, go farther.  As we move outside the Earth’s protective magnetic field, (i.e., orbit, Moon, Mars, and everything beyond and in-betwixt,) cosmic and solar radiation are essentially the greatest hazards an astronaut may face.  Radiation shielding and measurement are of primary importance.

Illustration of a manned NTR exploration spacecraft and landing capsule in Mars orbit. (Credit: Douglas/Time Magazine, 1963)

Farther still, once a spacecraft travels beyond about Mars, the intensity of sunlight is such that solar panels are inadequate to supply necessary power.  Nuclear reactors, (Radioisotope-Thermoelectric Generators, or RTGs,) are necessary.

Plus, in order to get out that far (to Mars or beyond) in a reasonable amount of time, our chemical rockets won’t provide enough kick.  Instead, Nuclear Thermal Rockets (NTRs) are about the most efficient way to go, something I’m in the midst of researching in earnest.

Hence, in addition to having experience as a field geologist (for future visits to the Moon, Mars, asteroids, etc.,) being trained to swing a radiation detector around, understanding the exact hazards radiation poses and how it works, and knowing your way around a nuclear reactor are all uniquely suited to space exploration.

Admittedly, it’s an unconventional path, but it’s my path: Riding gamma rays to the stars.

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Humanity’s outpost in the sky

8 09 2010

ISS and Atlantis (docked) visible in front of the Sun as seen from Earth. 05/22/2010. (Credit: Thierry Legault)

A short note this morning on humanity in the cosmos.  In the above image, an outstanding French photographer managed to capture what otherwise would have whipped by in the blink of an eye.

Crop of the ISS and Atlantis (docked) in front of the Sun. (Credit: Thierry Legault)

For an instant on May 22nd, the International Space Station (ISS) and the docked Atlantis orbiter (space shuttle) moved between Earth and the Sun as they screamed past at colossal orbital speed (16,500 miles per hour).  Rapid photography, meticulous planning, and much skill managed to catch the fleeting moment.

(The ISS and shuttle are visible to the left of the Sun’s center, with the station’s long pairs of solar panels bracketing the shuttle on the left-hand side, its nose angled away.)

My point in posting this morning, aside from sharing the epic “gee-whiz” factor implicit in this photograph, is to try and bring home something about scale, the cosmos, and our place in it.

While looking at the awe-inspiring photo, try to realize that the point of view of the photo -the Earth’s surface- is nearly 250 miles away from the ISS, but the Sun’s backdrop is a full 93 million miles behind it.

Think about that for a moment.  Another way of looking at it is that the ISS is nearly 360 feet wide.  The sun behind it is 4,567,200,000 feet wide, (or 865,000 miles in width, more than 100 Earths across.)  How big is that?  How far away does that have to be?

-That’s like holding out a matchbox car at arm’s length in California and having it be dwarfed by something sitting in Russia.

The ISS, taken from Atlantis as it undocked on May 23, 2010. (Credit: NASA)

When looking at the photo and realizing this immense reality of scale, the ISS’s cosmic ranking starts to come into perspective.  Even considering that the ISS is likely the most ambitious international effort ever attempted, (and by logical extension, arguably humanity’s most collectively ambitious project to date,) it is still clearly just the beginning of humanity’s toe-hold on the rest of the cosmos.

Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is.  (Thanks, Douglas…)  Ahem..

But seriously, maybe by looking at images like the above transit image by Theirry Legault and forcing your brain to accept what it knows to be true – that the station and all of its habitable space (roughly comparable to a 3,000 square-foot house) is just a speck, our entire Earth could be swallowed whole by the Sun without it even noticing, and our Sun is just a mediocre star amongst billions of burning brothers in the cosmos – we’ll all come to realize that we should really start moving out into the rest of the universe… just for safety’s sake.

We’re obviously really significant to ourselves.  Yet, to 99.999% of the rest of the universe, we haven’t even gotten into little league.  Metaphorically, no one knows we exist yet, and minor league players out there like asteroids and comets, (not to mention major league events like nearby supernovas,) can still easily wipe us out.

So, if we want a shot at winning the world series someday, (interpret the cosmic meaning of this increasingly threadbare analogy as you will,) we’d better start playing ball.

 

Artificial gravity and large-scale settlement space station designed by Wernher Von Braun. (Credit: Courtesy NASA/MSFC Historical Archives)





Suiting up for radiation

7 09 2010

Common radiation detection instruments. (Credit: Nevada Technical Associates, Inc.)

So, I’m heading out this week for radiological instrumentation training.  And while I’m studying the latest in handheld “duck-and-cover” devices, I thought I’d take a second to talk about radiation protection.

Actually, everyone is used to doing it.  The dental chair.  The strangely-shaped things in your mouth.  The lead apron.  -Or how about gooping up before hitting the beach or the hotel pool?  X-Ray Machines and UV rays.  -Not quite scary as they are inconvenient.

Well, what are x-rays and ultraviolet rays other than electromagnetic radiation?  -That’s right, they’re the same as the “radiation” that serves as the terror-inducing, little-understood plot point in a zillion bad sci-fi flicks.  X-rays are simply a stronger variant of the ultraviolet-rays that can fry your skin and a weaker variant of the gamma-rays that beam out of radioactive cesium and can fry your DNA.

The apron you wear at the dentist and the sunblock you slather on are common radiation shields.  And, for that matter, so is your skin.

Radiation is a way of life – it beams down from the sun and up from the Earth’s rocks.  Plants soak up naturally-radioactive potassium and beam radiation at you from all sides, 24-hours-a-day.  We’re built to handle it down here.  Life has adapted.  -And while politicians count on the scary sci-fi-effect the word “RADIATION” has on people, it’s nothing to worry about compared to the chemicals we deal with and transport in day-to-day life.  (Try breathing chlorine bleach for more than a couple of seconds and you’ll see what I mean.  But seriously, don’t do that.)

1999 solar eclipse, highlighting the sun's corona. (Credit: Luc Viatour)

In space, however, it’s a different story.  Without the Earth’s atmosphere to act as a natural shield, we’re unprotected from the sun and distant stars’ powerful cosmic radiation.

To make matters worse, most radiation shields (e.g., lead,) are heavy.  The cost of launching heavy materials up to space is enormous, not to mention that lead is a toxic metal, poisonous to astronauts with long exposure times.

It’s times like these that companies like Radiation Shield Technologies catch my eye.  While they’re not necessarily working on NASA-spirited technologies, (they’re more looking at the emergency responders,) the product they’re offering definitely has out-of-this-world merit.

Namely, they’ve developed a fabric called Demron, which according to a Lawrence Livermore National Laboratory study possesses many of the radiation-shielding properties of lead while being lightweight, flexible, and potentially layer-able with a bullet-proof fabric like Kevlar.

To me, products like this are where we need to start looking to develop the practical tools of next-generation astronauts and space workers (astrowrights).  While Demron currently doesn’t shield well against the most extreme high-energy rays and particles, it is definitely a start, and it’s much more user-friendly and cost-effective (lighter) than lead.

Considering what an effective combination Demron would be with the micrometeorite protection that a ballistic fabric like Kevlar would offer, I would challenge clothing designers to start putting their heads together to incorporate them into comfortable, practical space-wear for our men and women in orbit.

Like on Earth, radiation is a way of life in space, too.  We should start thinking that way, and Demron seems a good place to start.








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