[meteorite-list] Crash Planning: Mission to Deflect an Asteroid (Don Quijote)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Jul 13 20:26:34 2004
Message-ID: <200407140026.RAA27242_at_zagami.jpl.nasa.gov>


Crash Planning: Mission to Deflect an Asteroid
By Robert Roy Britt
13 July 2004

A mission to smash into a space rock to deflect it and study its
structure has been given priority over five other potential asteroid
projects by the European Space Agency.

The slam-bang Don Quijote mission would help scientists figure out how
to deflect or destroy any asteroid in the future that might be found to
be on a collision course with Earth. The project uses the Spanish
spelling of Don Quixote, the protagonist in Cervantes' novel who has
chivalrous ideas that tend toward the impractical.

The lofty modern-day Don Quijote would help solve a practical problem.

Scientists don't know enough about asteroid insides to predict how one
would respond to attempts to nudge it off an Earth-impact course or turn
it into harmless dust. While no asteroids are currently known to be on
track to hit the planet, experts say a regional catastrophe is
inevitable in the very long run, over millennia. And run-ins with small
asteroids that could incinerate a large city occur ever few thousand years.

"We want to investigate the internal structure of an asteroid, and at
the same time develop and test the technology necessary, in a worst case
scenario, to deflect a sizeable asteroid," says Andrea Milani, an
asteroid expert at the University of Pisa who is helping to plan the


The mission would involve two spacecraft -- Sancho and Hidalgo --
launched on different trajectories toward one asteroid about 550 yards
(500 meters) in diameter. A rock that size would cause serious damage
across a widespread area and absolute destruction at the local level.

The name of the mission "does not come from the lunatic ideas of Don
Quijote, but for the famous scene where Don Quijote fights against a
windmill while Sancho observes it from the distance," explained Jose
Gonzalez, head of mission analysis at DEIMOS Space, a Spanish company
that has led the Quijote planning. "In this case, Don Quijote is
fighting an asteroid."

Sancho would arrive first and orbit the asteroid for several months. It
would deploy some penetrating probes to form a seismic network on the
asteroid to examine its structure before and after its sister craft's
smashing arrival.

Hidalgo would crash into the asteroid at about 22,370 mph (10 kilometers
per second).

Sancho would observe from a safe distance, then move in for a closer
look. It would study changes in the asteroid's orbit, rotation and
structure caused by the impact, said Willy Benz, a member of the
mission's study team from the University of Bern in Switzerland.

The mission would "provide information about how an asteroid reacts to
such stresses, which is an important step in the whole impact hazard
reduction business," Benz told SPACE.com.

Funding required

On Friday, a European Space Agency panel considering six asteroid
protection missions recommended Don Quijote as the highest priority for
further studies. It is still in an early planning stage, however, and
would eventually need funding approval. Officials expect other agencies
to participate.

Benz said the mission could launch in five to six years.

Don Quijote is similar to NASA's Deep Impact
mission, which is slated to fling a small probe at a comet on July 4, 2005.

Comets are loaded with water ice, while asteroids are generally composed
of rock and metals. Scientists know little about either, and both are
thought to harbor clues about the solar system's formation.

>From a safe distance, the Deep Impact mothership will take pictures and
record other data as its probe blows a seven-story-deep crater in the
comet Tempel 1. Experts say Deep Impact's cosmic fireworks might be
visible from Earth to backyard skywatchers.

Both missions will alter the courses of the objects they hit.

Deep Impact will fly past its target, limiting the time for close-up
observations. The European craft, in orbit around its as-yet-unknown
target, would take a more detailed approach to studying the comet
before, during and after the collision.

"The important difference between Deep Impact and Don Quijote is that
the target asteroid is studied six to seven months prior to impact and
again three to four months after the impact," Benz said.

Shake it up

Don Quijote could create a seismic shift in the understanding of
asteroid interiors.

The probes that would be embedded in the asteroid prior to the main
event would monitor how the rock's structure changes in the collision by
recording seismic waves created by small explosions the probes detonate.
The method was used by Apollo astronauts to examine the Moon's interior,
and it's used on Earth to search for oil, natural gas and other minerals.

There are currently no firm plans by NASA or any other agency to deal
with any impending asteroid catastrophes. Scientists have contemplated
the theory of asteroid deflection and destruction
but no tests have been performed like the one planned in the Don Quijote

"Although the probability of a big impact is very small, for the first
time in human history we have the means of avoiding such a catastrophic
event," Jose Gonzalez, another member of the study team, has said. "But
it is essential that we improve our knowledge of asteroids. We must know
in detail the internal structure of asteroids, and how they respond to
impacts before we can design effective mitigation methods."

    * Destroying Asteroids with Space-based Missiles

    * Catastrophe Calculator: Estimate Asteroid Impact Effects Online
Received on Tue 13 Jul 2004 08:26:30 PM PDT

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