Everything You Wanted to Know About BEAM but Were Afraid to Ask

8 04 2016

Humanity’s first human-habitable inflatable spaceship, (or as those in the industry prefer to call it, “expandable” spacecraft), is soon to launch off-world.  Tucked inside a Dragon cargo transport‘s “trunk” and perched atop a SpaceX Falcon 9 rocket, this momentous departure targets the International Space Station (ISS) and is slated to occur today.

The precious expandable cargo is itself a simple test article, (or as those in the industry are keen to refer to it, a “pathfinder technology demonstrator”), which was manufactured by Bigelow Aerospace right here in Las Vegas, Nevada.  Aptly titled the Bigelow Expandable Activity Module, or BEAM, the craft is designed to attach to the ISS and stay put for at least two years to see how it behaves.

Now, media outlets large and small, having caught wind of this impending technological departure from the streampunk-like status quo, (where hulking, submarine-like cylindrical pressure vessels serve as our spacecraft shells), are repeating the same, few details with great enthusiasm.  However, general curiosity about BEAM’s design, structural elements, and expected performance is going generally unanswered.

Well, no more.  There’s no question too big or too small to answer, here!  So, for the intrepid of spirit, I hereby present the following 5-point breakdown of Everything You Wanted to Know About BEAM but Were Afraid to Ask… (using public-domain material, of course.)

 

1]  What are BEAM’s pair of small, antennae-like protrusions for, anyway?

BEAM FRGFs

BEAM’s aft bulkhead antennae? (Original credit: Bigelow Aerospace)

While they might look like tiny, satellite-TV-style dishes, these circular devices serve a radically different function.  Known as standard Flight-Releasable Grapple Fixtures, or FRGFs, they’re the means by which the ISS’s robotic arm will snare BEAM, yank it out of Dragon’s trunk, and plug it on to the ISS’s Node 3 module.

FRGF_on_Cupola

A Flight-Releasable Grapple Fixture, or FRGF, a necessary grip point for the International Space Station’s robotic arm. (Credit: NASA)

NASA provided Bigelow Aerospace with two FRGFs to install on BEAM as part of their contract.  Think of them as the receiving half of an enormous robotic handshake upon BEAM’s arrival at the ISS.

 

2]  What about the sleek, wavy metal collar on the ‘hatch’ side of BEAM?

BEAM PCBM

Sleek style or something more? (Original credit: SpaceX)

As it turns out, this eye-catching part of BEAM’s exterior was manufactured by the Sierra Nevada Corporation and is known as a Passive Common Berthing Mechanism, or (you guessed it), a PCBM.  This is a standard mechanism for unpowered craft that can’t dock to the ISS using their own thrusters and must therefore be snatched up by the ISS’s robotic arm and manually ‘plugged in’ to one of the station’s active ports.

585ae09d-f659-4d1d-8c88-9ad8be6b1c7f

A Passive Common Berthing Mechanism, necessary for forming a tight seal with the International Space Station. (Credit: Sierra Nevada Corporation)

The PCBM was supplied to Bigelow Aerospace by the Sierra Nevada Corporation as part of the NASA BEAM contract, and it was integrated into BEAM’s structure at Bigelow’s large North Las Vegas facility.

 

3]  So, what are BEAM’s walls actually made of?

BEAM softgoods

What makes sturdy spacecraft skin that can also crumple and fold for launch? (Original credit: Bigelow Aerospace)

Bigelow hasn’t released the specifics of the makeup of BEAM’s fabric walls, known as “softgoods.”  (Holding this extremely proprietary information close to the vest is unsurprising.)  However, despair not, curiosity-fueled space enthusiasts, for it turns out that much basic information about the Bigelow expandable spacecraft approach was published in a 2005 article in Popular Science, entitled, “The Five-Billion-Star Hotel.”

In the article, the walls of the expandable Bigelow “Nautilus” module under development at the time (later to be rechristened the B330 spacecraft) were described as having the following basic structure:

  1. “Five outer layers of graphite-fiber composites separated by foam spacers” that function as a micrometeorite and orbital debris (MMOD) shield.
  2. Moving inward, this is followed by a critical, intermediate layer known as the “restraint layer,” which serves as the load-bearing portion of the structure.  This layer is described as “a web of interwoven straps made of high-strength fiber.”
  3. Finally, the innermost layer, called the “air bladder,” is a “plastic film” that “keeps the internal atmosphere from escaping into space.”

Admittedly, it has been some time since the article was written, and details may have shifted somewhat in the intervening years.  -But, in a general sense, BEAM could be reasonably expected to follow the same sort of structural format.

For something a little more recent, one can also argue for a fairly close approximation of BEAM’s softgoods in another, modern inflatable spacecraft design.  European aerospace titan Thales Alenia Space (TAS), (responsible for the design and manufacture of the rigid shell backbones of the European Space Agency’s Automated Transfer Vehicle supply ships as well as the Cygnus cargo freighters, and others), has its own inflatable spacecraft design known as REMSIM.

REMSIM

A 2005 rendering of a REMSIM inflatable module, envisioned as a lunar habitat. (Credit: Thales Alenia Space)

Just as BEAM could be considered offspring of the cancelled NASA TransHab program, from which it inherited much of its technology and approach, so too does REMSIM descend from TransHab, making it a sort of European cousin to BEAM.   Standing for “Radiation Exposure and Mission Strategies for Interplanetary (Manned) Mission,” REMSIM was effectively the European Space Agency’s push (like Bigelow) to carry the TransHab torch into the 21st Century.  (REMSIM research and development is ongoing to this day.)

In landmark 2009 research presented at the International Symposium on Materials in a Space Environment, led by TAS researcher Roberto Destefanis, the REMSIM layers are revealed (and put through their paces).

Screen Shot 2016-04-08 at 7.15.18 AM

Softgoods layering details of the inflatable REMSIM spacecraft, a European cousin to Bigelow Aerospace’s BEAM. (Credit: Destefanis et al., 2009)

In the above diagram, MLI stands for Multi-Layer Insulation (think heat shield), BS stands for Ballistic Shield layer, and the rest are as described.  As can be seen, they generally agree with the Popular Science description of the Bigelow approach.

So, odds are, if you want to know what’s inside BEAM’s collapsible/expandable spacecraft skin, the REMSIM “stack” isn’t a bad place to start.

 

4]  Can BEAM really shield well against micrometeorite and orbital debris strikes?

BEAM MMOD

Will BEAM’s soft sides stand up to space impacts? (Original credit: NASA JSC)

When many are introduced to the concept of an inflatable spacecraft, a natural first reaction is alarm.  On Earth, most inflatable objects are very vulnerable to punctures and ruptures (e.g., party balloons).  Wouldn’t an inflatable spacecraft be far more vulnerable than rigid aluminum modules to micrometeorites and bits of space junk zipping around at mind-bending orbital speeds?

Well, much like a Kevlar vest has no problem stopping a bullet, it turns out that expandable spacecraft have no problem holding their own against impinging space chunks.  While specific information on how well BEAM’s softgoods hold up under punishment is proprietary, we can return once again to REMSIM for a good example.

IMG_2980

The aftermath of a micrometeorite impact test on a BEAM-similar expandable spacecraft design known as REMSIM, demonstrating that the inner layer remains unscathed. (Credit: Thales Alenia Space)

The Bigelow debris shielding approach, like REMSIM, uses what is called a Multi-Shock strategy.  Here, multiple thin, ballistic shield layers separated by some distance act to “shock” the incoming projectile and disperse its energy before it strikes (and potentially breaches) the pressure containment layer.

So, again returning to the 2009 Destefanis paper, REMSIM softgoods test articles boasted surviving getting blasted with half-inch aluminum spheres at speeds exceeding 15,000 miles per hour.  (This agrees with claims made in the aforementioned 2005 Popular Science article, which reports that Bigelow softgoods withstood a half-inch aluminum sphere impacting at better than 14,000 miles per hour.)  Not too shabby at all, and according to the research, meets or exceeds the debris protection performance of rigid ISS modules using traditional “stuffed” Whipple Shields.

This implies that BEAM’s protection factor against micrometeorites and debris is just fine, if not outright superior to rigid modules.

 

5]  What sort of radiation protection should we expect from BEAM?

BEAM Rad

This has been a big question, and one NASA has expressed particular interest in.  In fact, it’s one of the primary functions of BEAM to determine just how favorable the radiation protection qualities of a softgoods spacecraft are.

The problem with space radiation is that it is generally more massive and highly energetic compared to ionizing radiation encountered on Earth’s surface, which makes it difficult to shield.

The problem with talking about space radiation shielding is that it depends on a boatload of variables — the more active our Sun, the more it deflects even more damaging radiation from exploding stars in our own Galaxy (and beyond) but trades it for an increased risk of being hit with lower-energy but overwhelming solar storms.

tumblr_o53txgrsvO1tnfmy1o1_1280

Artist’s depiction of solar and cosmic radiation at the fringe of Earth’s magnetic field. (Uncredited)

Blanket statements about how anything shields radiation in space are therefore difficult to reliably make, requiring multiple models and depending strongly on orbit altitude, timing, and precise material breakdown.  As a result, experts tend to either sound uncertain or evasive.

Keeping all of this in mind, if we return to the 2009 Destefanis study one final time, we find it has something to say about this as well.

By placing test articles meant to represent different types of spacecraft and spacecraft materials in front of particle accelerators powerful enough to fling atoms as large and fast as those fired into the cosmos by exploding stars, researchers can reliably predict how materials will shield against space radiation.  This is exactly what the Destefanis study reports, using an iron-atom slinging accelerator at Brookhaven National Lab.

Screen Shot 2016-04-08 at 10.01.10 AM

Expected shielding performance of BEAM-like REMSIM compared with varying thicknesses of different materials and ISS module compositions. (Credit: Destefanis et al., 2009)

The results of the Destefanis work reveal that against the most damaging type of radiation experienced at the ISS (heavy Galactic Cosmic Rays), REMSIM shields nearly half as well (3%) as an empty ISS module (8.2%).  It achieves this with less than a third of the equivalent mass, demonstrating a pound-for-pound benefit in REMSIM’s favor, not to mention the unprecedented capability of squeezing into a tiny payload space during launch.

In a big-picture sense, the chart also reveals that REMSIM shields only 10% as well against heavy GCR as a fully-outfitted ISS module (3% versus 28.7%).  While this might sound terrible at first glance, this is due largely to the fact that Columbus is currently far from empty, ringed with equipment racks, piping, tubing, cabling, and supplies.  All of this extra material serves as supplemental shielding for astronauts located within.

By contrast, the basic REMSIM in this study is (like BEAM) completely empty, making the “10%” claim a somewhat unfair apples-to-oranges comparison.  However, numbers like these more closely match the current situation between BEAM and the rest of ISS.

So, ultimately, if the REMSIM-BEAM comparison holds, one might expect a similar ratio between GCR-radiation shielding measurements made in BEAM and parallel readings taken across the rest of the ISS.  And while the numbers might sound grim to the uninitiated, numbers like these are going to be exactly what NASA is looking for.

_________

I hope the information compiled in this post has been helpful at least to some, and as always, feedback is welcome.

Semper Exploro!

 

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System of Fear: A Dose of Radiation Reality

14 10 2013

In line with last week’s post, please see the below infographic, which paints radiation doses in the visual context of a sort of system of planets according to size (click to enlarge):

SystemofFearI

As is plainly evident, it’s shocking how much the public perception of radiation doses and negative health effects differs from reality.

(For example, in today’s perceptual climate, who would believe that a person could live within a mile of a nuclear powerplant for a thousand years before receiving the radiation dose from a single medical CT scan?)

If feedback to this is positive, I think I’ll make this the first in a series of similar infographics.  (Perhaps people would find it interesting/useful to next have illustrated the relative magnitudes of nuclear disasters?)

_______________________________________________

If anyone doubts the numbers in the above diagram, please feel free to investigate the references for yourselves!

International Atomic Energy Agency:
http://www.iaea.org/Publications/Factsheets/English/radlife.html

U.S. Environmental Protection Agency:
http://www.epa.gov/radiation/understand/perspective.html

U.S. Nuclear Regulatory Commission:
http://www.nrc.gov/about-nrc/radiation/around-us/doses-daily-lives.html

U.S. National Council on Radiological Protection (via the Health Physics Society):
http://hps.org/documents/environmental_radiation_fact_sheet.pdf

U.S. Department of Energy:
http://lowdose.energy.gov/faqs.aspx#05





Nuclear and Atomic Radiation Concepts Pictographically Demystified

10 10 2013

Greetings, all.  Today I’m attempting a different, largely pictographic approach to demystifying the concept of “radiation” for the layperson.

Despite the hype, radiation is a natural part of our planet’s, solar system’s, and galaxy’s environment, and one that our biology is equipped to mitigate at ordinary intensities.  It’s all actually surprisingly straightforward.

So, without further ado, here goes – a post in two parts…

PART I – Radiation and Radioactivity Explained in 60 Seconds:

The Atom

This is a generic diagram of the atom, which in various combinations of the same bits and parts is the basic unique building block of all matter in the universe:

Atom_Labels

This somewhat simplified view of an atom is what makes up the classic “atomic” symbol that most of us were exposed to at the very least in high school.

Radioactive Atoms

However, what is almost never explained in school is that each atomic element comes in different versions – slimmer ones and fatter ones.  When an atom’s core gets too large, either naturally or artificially, it starts to radiate bits of itself away in order to “slim down.”  This is called being radio-active.

So, there’s nothing to “radiation” that we all haven’t been introduced to in school.  Radiation is the name given to familiar bits of atoms (electrons, protons, neutrons) or beams of light when they’re being flung away by an element trying desperately to squeeze into last year’s jeans… metaphorically-speaking, of course.

Here is a diagram illustrating this process.  (Relax! – this is the most complicated-looking diagram in this post):

RadioactiveAtom_Radiation_Labels

So, when a radioactive element has radiated enough of itself away and is no longer too large, it is no longer radioactive.  (We say it has “decayed.”)

That’s it!

That’s as complicated as the essential principles of radiation and radioactivity get.  It’s just basic chemistry that isn’t covered in high school, (though in my opinion it should be!).

PART II – Take-Home Radiation Infographics

So, in an effort to help arm you against the rampant misinformation out there, here is a collection of simple diagrams explaining what everyone out there seems to get wrong.  (Feel free to promote and/or distribute with attribution!)

First, what’s the deal with “atomic” energy/radiation versus “nuclear” energy/radiation?  Do they mean the same thing?  Do they not?  Here’s the skinny:

AtomicvsNuclear_labels

That’s all.  “Nuclear” means you’ve zeroed in on an atom’s core, whereas “atomic” means you’re talking about something dealing with whole atoms.  No big mystery there.

Next, here is a simple diagram explaining the three terms used to describe radiation that are commonly misused in the media, presented clearly (click to enlarge):

MisusedTerms_labels

(Armed with this, you should be able to see why saying something like, “The radiation is releasing contamination!” doesn’t make a lick of sense.)

Now, here is a diagram explaining the natural sources of radiation we’re exposed to everyday on planet Earth:

RadiationNaturalSources_labels

And here are the basic principles of radiation safety, all on one, clean diagram (click to enlarge):

RadiationSafetyv2_labels

The End! 

Despite the time and effort spent socially (politically?) promoting an obscured view of this science (or so it seems), there is nothing more mysterious about radiation than what you see here.

Please feel free to contact me with any questions, and remember:  We have nothing to fear but fear itself!

Semper Exploro!





Talking Space Radiation Dosimetry at NSRC 2013

24 06 2013
Having an unashamedly good time stealing a few moments between talks inside the XCor Lynx spacecraft mockup parked behind NSRC 2013.

Having an unashamedly good time stealing a few moments between talks inside the XCor Lynx spacecraft mockup parked behind NSRC 2013.

I recently had the great pleasure to give a talk (and serve as co-author for a second) at the fourth annual Next Generation Suborbital Researchers Conference (NSRC), held this year in Boulder, Colorado.

As a one-of-a-kind collection of researchers, entrepreneurs, spacecraft providers, students, and government representatives, NSRC’s intent is to foster collaboration of a sort that will enable the research world to fully utilize what amount to a fleet of new spacecraft looking to come online within the next 24 months.  In all, exciting to be amongst like-minded folks, great to see familiar faces again, and a thrill to forge new alliances.

Two Radiation Take-Homes for the Suborbital Space Community

IMG_4535So, what was I doing there?  In brief, on behalf of my spaceflight consulting firm, Astrowright, I made a daring and ill-advised attempt to shove a 40-slide presentation into 10 minutes, with (based on positive feedback) it seems at least a small amount of success.  (I wouldn’t have even made such a blitzkrieg attempt unless it was absolutely necessary in the context of my talk.)

The intent?  To give a broad enough overview of radiation detector theory so that I had a prayer of communicating to this very select audience two imminent realities of space radiation dosimetry:

  1. The private/commercial spaceflight world, particularly in the suborbital context, is primed to (mis)use off-the-shelf radiation dosimeters designed for the commercial nuclear world; these instruments will not deliver complete or ultimately meaningful numbers without applying specific scaling algorithms to the results, in essence calibrating them for the space environment.  User beware!
  2. The greatest benefit of bothering to outfit suborbital astronauts with radiation dosimeters might not be to the spaceflight participants themselves, (who would receive in all but the most extraordinary circumstances a practically immeasurable radiation dose).  Instead, the greatest effect may be to improve Earth-based low-dose modeling and safety standards, the researchers engaged in which would benefit immeasurably from having a completely new population group to study who are intentionally exposing themselves to low-dose, high-intensity radiation.  This is also, *hint hint*, a completely untapped research funding angle (contact me if interested in collaborating – seriously!).

So, there you have it.  If not taking advantage of my own firm’s radiation dosimetry services, my message to the suborbital spaceflight world was to at least engage in planning one’s own flight experience armed to understand that accurate dosimetry in the space environment is not something one can just pull off a shelf and slap on the outside of a pressure suit!

Space Training Roadmap

The second talk, which was expertly given by co-conspirator Dr. Mindy Howard of Inner Space Training, involved a task-based assessment of potential spaceflight tasks for suborbital spaceflight participant.  The objective there?  The development of a spaceflight training “roadmap” to help participants decide which training amongst the many types offered by providers is relevant and necessary for their personal flight goals.

The power to decide which training is or is not relevant to an individual should not, in my opinion, be left up to the spacecraft providers (who may and likely will not have your specific goals in mind)!  That’s where our roadmap research comes in.

Please feel free to contact me or Dr. Howard for any additional details along those lines.

Lingering Thoughts

Well, the pulse at the conference was that the next twelve months appear to be crucial.  With business plans starting to kick in and metal finally being flight tested, I feel as though there are two distinct options for NSRC 2014: It will either be aflood with the excitement borne of the dawn of commercial suborbital spaceflight, or attendance will plummet as cynicism and a fear of perpetual development cycles sets in.

For now, the future looks bright, and that’s good news!

Until next time, NSRC.  Cheers!

IMG_4534

Having an equally unashamedly-good time having the opportunity to give a NSRC presentation about a topic that’s actually in my field of expertise! (I’ve been fielding for other sides of the house the past couple of years…)





The Science Behind “Chasing UFOs” – Episode 2

30 06 2012
https://i2.wp.com/tvblogs.nationalgeographic.com/files/2012/06/edit-diagram-blog.jpg

Fieldbook sketch of possible crash sighting and survey sites outside of Fresno, CA. (Credit: Ben McGee)

For those who might like to delve more deeply into (or simply know more about the science behind) the second episode of National Geographic’s TV series “Chasing UFOs,” including industrial archaeology, cargo cults, radioactive tunnels, and orienteering troubles, check it out!

Direct link to my article on the NatGeo TV blog here:

http://tvblogs.nationalgeographic.com/2012/06/30/the-science-of-chasing-ufos-dirty-secrets/

Cheers!

Ben





Calculating your own natural radiation dose in context

26 06 2012

 

Traditional Radiation Trefoil Hazard Symbol. (Image credit: ORAU)

A Dose of Radiation Information

How much radiation is normal?

In light of Fukushima, sensationalized media, political fear-stoking, and rampant misinformation regarding radioactivity, consider this post an easy-to-reference tool/resource.  With it, you can be armed to understand and quickly make sense of this over-mystified, natural aspect of reality when it comes up.

For starters, here’s the simple reality about how much radiation you receive in a year just for standing on Planet Earth:

The average natural annual radiation dose for a U.S. resident is about 300 millirem, and when including man-made commercial products and medical procedures (MRI scans, etc.), the average dose jumps up to 600 millirem per year.  This is what we all get every year and bears no known, measured relationship to developing cancer.

  • Note: For the international units, divide all “millirem” numbers by 100, (i.e. 3.6 millisieverts.)  Or, an online converter can be found here.

However, what does that mean?  I’m completely aware that unless you’re a professional in the field of health physics, (as I am,) this number has no context.  So, allow me to explain just what this really means using things we can all identify with.

Hold on to your hats.

So, What’s My Dose?

For context, below is a list of the amount of radioactivity you receive in a year from very familiar items/sources:

  • Cosmic radiation  = 26-96 millirem (higher with altitude)
  • From standing on the Earth itself (geology) = 20-90 millirem (higher nearer igneous mountains)
  • From your own brick/stone/concrete building = 7 millirem
  • From your own body (food/water!) = 40 millirem
  • From breathing (naturally-produced radon) = 200+ millirem
  • For flying 1,000 miles in an airplane = 1 millirem
  • From having a dental/chest/normal x-ray = 50 millirem each
  • From having an annual mammogram = 75 millirem
  • From having a single CT scan = 150 millirem
  • From smoking a pack of cigarettes a week (polonium) = 200 millirem
  • From consumer goods = 10 millirem

Just add these up to produce your own, custom average annual radiation dose.

Wait.  My house/food/body/atmosphere is radioactive?

Yes.  Not to fear.  Just like the small amounts of chemicals that we can reliably tolerate, (e.g., trace arsenic, lead, etc.,) so too are trace amounts of radioactivity completely tolerable.

Fukushima in Context

Now, as you can see in the above plot of the radioactivity measured at the entrance of Fukushima nuclear powerplant as the disaster happened, it looks pretty dramatic.

  • (Note: The numbers are reported in “micro”sieverts per hour, which are admittedly reading a much smaller span of time, (hours versus years,) but are in units 1,000 times smaller than the “milli”sievert international units described above.  This is important.)

However, instead of running for the hills just yet, let’s take a look at what the numbers actually say.

The March 15th hydrogen explosion at the plant, which occured roughly 84 hours after the earthquake, shows the largest spike of activity: for a brief period upwards of nearly 12,000 microsieverts per hour.

But let’s take this apart.  What does that mean?  12,000 microsieverts is the same as 12 millisieverts.  12 millisieverts is the same as 1,200 millirem.

Now, compare this to the above list of natural radiation values, with an eye toward the annual average does of 360 millirem.

Yes, if reading correctly, this implies that simply standing on planet Earth every year nets everyone the same external radiation dose that would have been received if standing at the gates of the Fukushima Daichi powerplant during the worst part of the disaster for a full 15 minutes.

With these, even worst-case numbers, it becomes obvious that one could stand at the entrance to Fukushima during the worst period of the disaster for a full three minutes and have earned only the equivalent radiation dose of… an average chest x-ray.

Granted, this isn’t something one would necessarily want.  This is upwards of 15% of your natural average dose.  -But your biology wouldn’t ever notice the difference.  And one could go many orders of magnitude more than that before there would be any reasonable expectation of an acute health effect.

More realistically, even standing at the Fukushima gates during the unprecedented event of external venting from the internal containment of reactor number 2, (with an exposure rate of 0.5 millisievert per hour), it’s a full hour of loitering there before one would rack up the external exposure of simple set of dental x-rays.

Funny how the perception and the reality differ, eh?

Unwanted radioactive material is serious, just as a leak from underground gasoline storage tanks that could contaminate drinking water is serious.  But that seriousness must be given honest context.

Take-home

Hopefully this has provided a window into the reality of radiation protection, and it is my sincere wish that this was and will continue to be a useful go-to when radiation numbers come up in the media.

Feedback is welcome, and if desired, I would be happy to put other radiation values in context… (Chernobyl, Three Mile Island, going to the Moon, etc.)

Go forth and combat radiation misinformation!

[Sources for the above information: American Nuclear Society, the National Council on Radiation Protection and Measurement, the U.S. Department of Energy.]





Summer Hits: Martian Water, Asteroid Nukes, Orbital Antimatter!

1 10 2011

Here’s a recap of some of this summer’s greatest hits in space news that you might have missed:

Water on Mars

Dark streaks as summer flow features in Newton Crater, Mars. (Credit: NASA)

In an utterly tantalizing development, scientists analyzing imagery from the Mars Reconnaissance Orbiter (MRO) have announced what appears for all the world to be direct evidence of water on Mars!

Because the MRO has been orbiting the Red Planet since 2006, it has been able to view the same portions of the world at different times of year with an eye toward spotting any potential seasonal changes.  This past August, the MRO team reviewing this growing dataset hit paydirt.

Specifically, the team identified dark streaks on the slopes of steep terrain in the southern hemisphere that are found during Martian spring and summer; these features disappear during Martian winter only to return once again the following spring.

While there are multiple possible explanations, the most likely amongst them appears to be the flow of briny (salty) groundwater that warms in the hotter months, breaches the surface, and evaporates/sublimates as it flows downhill.

Time will tell on this one, but all eyes should be on the possibility of subsurface briny Martian aquifers!

Russian “Armageddon”

Asteroid impact as depicted in the film "Deep Impact." (Credit: Paramount/Dreamworks)

This past August, Russian scientists took a note from Hollywood and seriously proposed the use of nuclear weapons as a means of asteroid mitigation.

Under the scenario, a dual-spacecraft architecture would be employed, with one spacecraft, called “Trap,” ferrying a nuclear warhead to the target while a second spacecraft, “Kaissa,” (apparently and intriguingly named after the mythical goddess of chess,) analyzes the target asteroid’s composition to determine the appropriate warhead use scenario (deflection vs. break-up).

The spacecraft would be lofted by a Soyuz-2 rocket and/or Russia’s upcoming Rus-M rocket.

While much contemporary research casts doubt on the ultimate effectiveness of a nuclear detonation in such a context, the proposers stressed that the technique would only be used on approaching objects up to 600 yards in diameter.

Orbital Antimatter Belt

Antiprotons trapped in the Earth's magnetic field (in pink). (Credit: Aaron Kaase/NASA/Goddard)

Also this past August, researchers published a stunning (but in retrospect, sensible) discovery in Astrophysical Journal Letters: Earth possess a natural orbiting belt of concentrated antiprotons.

Succinctly, the interactions of high-energy cosmic radiation with the Earth’s atmosphere can produce infinitesimal and ordinarily short-lived bursts of antimatter.  These antiparticles normally react with standard matter present around the Earth and annihilate.

However, in the near-vacuum of space beyond the bulk of the Earth’s atmosphere, some of these antimatter particles are spared immediate destruction.  Many of these antiprotons are then herded by the Earth’s magnetic field into bands or belts, which were recently discovered by the antimatter-hunting satellite PAMELA.

Aside from the “gee-whiz” factor, there are certain technical and economic reasons to get excited about the finding.  For starters, the energy density of antiprotons is on the order of a billion times greater than conventional chemical batteries.  However, at a current production cost on Earth of nearly $63 trillion per gram, antiprotons are a bit hard to come by and even less practical to use for anything other than research; Identifying a natural reservoir such as, say, a naturally-produced orbiting belt could open up additional avenues of use for antimatter as well as be immensely lucrative… if only one could solve the lightning-in-a-bottle problem of antimatter storage.

In any case, this is definitely something to keep an eye on.  For the less techno-jargon-inclined, news reports on the find may be found from the BBC as well as Science Magazine.








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