[meteorite-list] Mission Possible: Asteroid Tugboat Backed for Trial Run

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:28:29 2004
Message-ID: <200310151533.IAA20306_at_zagami.jpl.nasa.gov>

http://www.space.com/businesstechnology/technology/asteroid_tug_031015.html

Mission Possible: Asteroid Tugboat Backed for Trial Run
By Leonard David
space.com
15 October 2003

BOULDER, Colorado -- In the grand cosmic scheme of things, it's only a
matter of time. Our planet is bound to tangle with an Earth-crossing
asteroid, an event sure to make a mess. Some of these space rocks could
demolish a city. Other monster boulders, the really big bruisers, could
snuff out our civilization.

But why be at the mercy of a menacing asteroid that has Earth in its cross
hairs? Now an expert team of astronauts and space scientists has blueprinted
a safety strategy for Earth: an asteroid tugboat. The group says NASA is
already working on the right recipe of technologies to make the tug a
reality. It would be the greatest public safety project in history.
Furthermore, they propose a mission to demonstrate the asteroid-tug concept
by 2015.

Details of the asteroid tug are unveiled in the November 2003 issue of
Scientific American.

Lead author of the article is former astronaut, Rusty Schweickart, Apollo
9's lunar module pilot that put the Moon landing craft through its paces
high above Earth in March 1969. Other contributors are Piet Hut, Professor
of Interdisciplinary Studies at the Institute for Advanced Study in
Princeton, New Jersey, and asteroid specialist, Clark Chapman of the
Southwest Research Institute here in Boulder.

One more co-author is NASA astronaut Edward Lu. He is now resident onboard
the International Space Station and, in fact, e-mailed final article edits
on behalf of his fellow writers while circling Earth.

The asteroid tug test project is dubbed the B612 mission. That's the name of
the asteroid in The Little Prince, the well-known young person's book by
Antoine de St. Exupery. In fact, late last year, Schweickart, Lu, Hut and
Chapman formed the B612 Foundation, a nonprofit group dedicated to
developing and demonstrating the capability to deflect asteroids from Earth.

The premise behind the proposal, however, is no child's play. It's a way to
ward off the doomsday rock that will sooner or later terrorize humanity.

Ugly date with Earth

Over the years, numbers of schemes to deal with bully asteroids have been
proposed. Among them is blasting the beast to smithereens via a nuclear
bomb. Another thought is planting a nuclear device on one side of the
asteroid, then detonating the bomb to accelerate the space rock slightly in
the opposite direction.

"The problem, however, is that the results are neither predictable nor
controllable," Schweickart and his colleagues suggest. Also, such an
explosion could split the asteroid into pieces, leaving multiple headaches
of heavenly flotsam.

Then there's the kamikaze approach. Just crash a large robotic spacecraft
into a worrisome asteroid at high speed. This too has its problems. Namely,
you could just spin the body or knock off a small chip.

Other ideas are reviewed by the B612 think team and are highlighted in the
Scientific American article. In their view, an asteroid is a "push over"?
push it just enough to miss an ugly date with Earth.

Given enough warning time, an asteroid tugboat could nestle up to the
mini-world, then provide long stints of gentle pressure. The tug would nudge
the asteroid ever so slightly, but enough to shift the space rock's orbit so
an Earth collision is averted.

Mission possible

The B612 test mission to deflect an asteroid could use Variable Specific
Impulse Magnetoplasma Rocket (VASIMR) engines. The VASIMR propulsion unit
employs radio waves to ionize a gas and accelerate the plasma to even higher
exhaust velocities. Veteran shuttle astronaut, Franklin Chang-Diaz, is
exploring this novel, low-thrust propulsion technology.

Other equipment ideal for steering into the B612 project is scattered
throughout NASA. Specifically, the space agency's Prometheus Project to
design a space-rated nuclear reactor is a plus for any asteroid deflection
scheme. Work is underway for a Prometheus flagship mission - the Jupiter Icy
Moons Orbiter (JIMO). Hardware stemming from JIMO, the nuclear power plant,
radiator panels, a lengthy truss, and other equipment could help nurture the
asteroid tug into being.

The practice B612 mission would verify maneuvering around a target asteroid,
rendezvousing with and then attaching itself to the body. No easy set of job
tasks.

Additionally, the tug would have to hold tight to its target asteroid.
Procedures to deal with a spinning body would have to be ironed out. Once
secure to the space rock -- some 655 feet (200-meters) wide -- the tug must
use onboard engines for months to accelerate the asteroid in the desired
direction.

According to Schweickart and his fellow asteroid tug advocates, the training
mission would have a price tag of about $1 billion. They believe that this
extraterrestrial exercise could be accomplished by 2015.

"By practicing an asteroid deflection, the B612 mission would show whether
the asteroid-tug concept is feasible and, if so, how it should be refined in
the event of a real impact threat," the study team writes.

Schweickart told SPACE.com that the B612 proposal is meant to educate public
and political communities to the fact that Earth-approaching asteroids are a
natural, environmental threat. "Unlike earthquakes, hurricanes, etc., we can
actually do something about them. The capability to take this action is
within reach of today's -- or tomorrow's -- technology," he said.

Schweickart said the cost of a trial-run asteroid tug mission is quite
modest and well within the capability of the NASA budget to handle.

"However, the expenditure necessary to establish an operational system it
will require both money and international coordination," Schweickart added,
"and both will require a level of determination and commitment that may be
hard to come by without strong and clear demand by the general public."

False alarms

Just how much serious attention can the B612 proposal hope to garner?

One factor that might cause more a yawn than action is the number of
on-again/off-again threats from the sky. Those are the already numerous
predictions and projections that later turned out not to be sure bets.

"Of course, we want our response to the impact threat to be part of a
serious, objective approach to a considered evaluation of what the threat
is," explains asteroid specialist, Clark Chapman.

"So we don't like the irresponsible treatment of the threat by some
individuals and some -- especially British -- news media, although we
understand the psychological difficulties of dealing with tiny probabilities
of horrible events," Chapman said. On the other hand, he noted that "any
news is good news".

"I am not specifically aware of important decision-makers holding views that
have explicitly changed -- in either direction -- as a result of the false
alarms," Chapman explained.

Wanted: serious consideration

The general message from B612, Chapman concluded, is to try and develop,
with private funds, an exciting and important demonstration project that
will robustly bring everyone up the learning curve of what to do if a
threatening Near Earth Object is eventually found to be heading Earth's way.

"We hope that public concerns about this issue can be translated into real
financial contributions to bring these concepts to a point where we could
expect serious consideration by one or more space agencies - agencies that
have not yet officially put asteroid mitigation into their plans," Chapman
noted.

Chapman said that NASA's current Prometheus Project looks like an approach
to deep space missions that would be particularly well suited to the B612
proposal.

"Obviously, beyond the mere demonstration of engineering that could
conceivably 'save the planet' -- or at least a small part of the planet --
there would be dramatic opportunities to learn about how to deal with a
nearly gravity-free body in space," Chapman said, "both to scientifically
study asteroids and meteorite parent bodies and to consider eventual
asteroid mining operations."
Received on Wed 15 Oct 2003 11:33:57 AM PDT