Plans afoot for snaring a space rock

2 10 2011

Trajectory of 2008EA9 before and after orbit maneuver. (Credit: Hexi et al., 2011)

Researchers at the Tsinghua University in Beijing recently published a plan just daring enough to work/make people nervous.

After an extensive review of the orbits of thousands of candidate near-Earth objects, the research team headed by Associate Professor Baoyin Hexi identified a small asteroid that with a nudge at the opportune moment would settle into a temporary Earth orbit.

The 410-meter-per-second-boost required to snare 30-foot-wide asteroid 2008EA9 is but a fraction of the propulsion cost required, for instance, for our spacecraft to get to low Earth orbit, (8,000 meters-per-second).

Attempting such a technical feat would be a boon for space logistics and exploration research by providing a simple, local target for investigation by astronauts.  Further, the experience would exponentially improve our asteroid diversion know-how and spur the development of space resource/mining techniques.

Despite the terror-stoking hype that any asteroid-grab project is bound to inspire, the risks in this case are relatively low: few realize that asteroids of similar size (5-10 meters in diameter) hit the Earth’s atmosphere annually.  While still packing the punch of an mid-twentieth century atom-bomb, these objects are small enough to vaporize in the upper atmosphere, and typically no one is the wiser for it.

I say let’s go for it.  Any eccentric, research-minded philanthropists want to drop a fortune on lassoing a giant lump of primordial solar system?

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.

Lockheed Martin’s asteroid gambit

24 09 2010

Orion capsule docked w/ Orion Deep Space Vehicle modification. (Credit: Lockheed Martin)

The Obama Administration’s recent space initiative scraps former President Bush’s Orion moon program and planned moon base in favor of three basic components: Private industry, an asteroid rendezvous by 2025, and a manned Mars orbit by 2035.

Not wasting any time on nostalgia, aerospace industry giant Lockheed Martin, who had been helming the all-but-cancelled Orion spacecraft development, has seized on the suggestion and released a comprehensive proposal for how NASA can make the next off-world visit using their existing (or nearly-existing) Orion technology.

Citing a trinity rationale, “Security, Curiosity, and Prosperity,” Lockheed Martin’s proposal details how two Orion capsules and service modules (or one standard Orion capsule plus a SuperOrion they call the Orion Deep Space Vehicle,) can rendezvous with and explore one of a small class of Near-Earth-Objects (read: asteroids) that happen to swing close to Earth.

Orion spacecraft parked in orbit of an asteroid. (Credit: Lockheed Martin)

So, what does, “Security, Curiosity, and Prosperity” mean?  Lockheed Martin ventures that security is a reason to visit an asteroid so that we can develop necessary interception know-how and experience should we ever have to try and divert one.  Curiosity is reason to visit according to the plan because of the potential scientific boon exploring an asteroid would be for solar system formation research and planetary geology.  Lastly, they mention prosperity due to the fact that there is a very real possibility that “mining” an asteroid for natural resources could be quite lucrative.

What are the pitfalls?  The primary added risk of the asteroid mission over a lunar mission is distance.   Should something mechanically or medically go wrong, the shortest possible emergency return trip is on the order of months instead of days.  There is also a more prolonged exposure to radiation to consider.

However, the risk of an asteroid mission is also significantly reduced compared to a lunar mission in that two return capsules are taken along, so if something goes wrong with one, astronauts can still use the other to get home.  More importantly, there is no landing module, no landing and launch logistics to manage, and therefore no real chance of crashing.  Because an asteroid of this nature is so small (and its gravity weak), astronauts could literally park their Orion spacecraft next to the asteroid and spacewalk over to it.

Personally, I think this is fantastic.  This may just the geologist in me talking, but I think Lockheed Martin’s “Security, Curiosity, Prosperity” concept is a home run.  We really should be developing skills necessary in case we find an inbound asteroid with a high probability of a strike.  (Else, why are we spending so much time and effort looking out for asteroids that might hit us?)  The curiosity factor is a given, and I have personally been championing the “resourcing” of asteroids, (if I can make that a verb,) for years as a way of enabling larger space endeavors while reducing the “resource load” on Earth…

It’s also worth noting that the general experience of traveling through deep space would also be very, very useful experience for future trips to Mars.

So, will NASA go for it?  I think they’d be wise to.  They’ll be hard-pressed to find a more well-motivated mission with acceptable risk, redundancy, and potential payoff.


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