[meteorite-list] In Defense of Earth: Keeping Asteroids at a Distance

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:25 2004
Message-ID: <200302051653.IAA04271_at_zagami.jpl.nasa.gov>

http://space.com/businesstechnology/technology/asteroid_deflection_030205.html

In Defense of Earth: Keeping Asteroids at a Distance
By Leonard David
space.com
05 February 2003

BOULDER, COLORADO -- A group of astronauts, scientists, and technologists
want to engage in celestial shoving match. The winner may well be the Earth.

The goal of an assembly of experts is straightforward: To significantly
alter the orbit of an asteroid "in a controlled manner" by the year 2015.
They have dubbed their effort the B612 Project, brought into being by what
the group feels is a current lack of action to protect the Earth from the
impact of near Earth asteroids (NEAs).

For the immediate future, they point out, the changes are slim that our
planet will be at the end of the trail for a space rock - one that would
cause a highly destructive impact.

Nevertheless, the upshot from a heavenly slam shot is extreme, say B612
Project officials, so much so that mitigation efforts should start now.

Those involved in the B612 Project believe that by physically deflecting a
representative asteroid -- one not headed toward the Earth -- is a
worthwhile a trial project. Thus, a longer term, more challenging
operational system can become a reality.

Let's get pushy

It's high time to get pushy with Earth menacing asteroids, suggests Apollo 9
astronaut, Russell Schweickart, chairman of the B612 Foundation and a
retired business and government executive. The capability and technological
wherewithal to anticipate and prevent an asteroid impact is now available,
he contends.

If B612 sounds familiar, there is a reason. That's the asteroidal address
for The Little Prince, authored by the French writer Antoine de Saint
Exupery in 1943.

The B612 Foundation is a non-profit private organization with principal
offices in Houston, Texas. It was formed late last year to champion the
development of a space system to protect the Earth from future asteroid
impacts.

"Nothing like being part of the largest environmental project of all time,"
Schweickart explains.

Schweickart recently advocated the need for a United Nations "Asteroid
Deflection Treaty" - an international agreement to help shape a "trustworthy
system" that nudges threatening space rocks out of harm's way.

"Since new Earth approaching asteroids are discovered every day, initiation
of this effort should begin as soon as possible," Schweickart noted during a
special Organization of Economic Cooperation and Development (OECD) workshop
on "Near Earth Objects: Risks, Policies and Actions", held January 20-22 in
Frascati, Italy.

"When specific knowledge of an impact exists, it will be known by the world
public in real time. It seems highly likely that, when that time comes,
there will be widespread public expectation that these matters will already
have been resolved," Schweickart said.

Action item strategy

One of the action items on the foundation's to do list this year is
developing the first version of a "design reference mission" - laying out
the requirements for a demonstration mission to deflect an asteroid by 2015.

"Our strategy calls for the use of a long duration, low thrust system design
to rendezvous and directly dock with the asteroid," Schweickart told
SPACE.com from his office in the Netherlands. "We would then utilize the
system to first de-rotate the asteroid and then push it tugboat fashion. We
call it a NEA-Tug - changing its velocity - over many months," he said.

The attachment of a NEA-Tug to a tumbling asteroid's surface -- along with
control issues during de-rotation and acceleration -- "raise substantial
questions that must be answered," Schweickart added. Due to the NEA-Tug's
low thrust level, he said, many of the issues related to an asteroid's
structural integrity and surface characteristics are not likely to be an
issue.

Assurance policy

Honing the hardware for asteroid deflection means putting dollars into space
power and propulsion. Doing so would also yield a scientific bonanza too.

"From an institutional perspective the biggest challenge I see is making the
decision to spend money on the effort and to assigning responsibility for
getting the job done," Schweickart said. "We are not proposing an
operational system. We are proposing that a demonstration mission be
performed to meet several goals," he said.

Among those goals is stimulating the development of the enabling
technologies. Chiefly, those involve nuclear/electric power generation and
plasma or ion propulsion. Furthermore, there's need to clearly assure the
public that should a pending asteroid impact be discovered in the next
decade or so, the necessary technologies and techniques to protect the Earth
are available.

"Since the basic technologies we propose to use for asteroid deflection will
also enable cost effective missions beyond low Earth orbit for both
scientific research and, potentially, resource exploitation, the incremental
funding required for this purpose is small. Yet great public benefit is
gained by utilizing this mission to demonstrate the new power and propulsion
technologies," Schweickart noted.

Practice before proceeding

Joining Schweickart in B612 Foundation work is noted asteroid expert, Clark
Chapman, a scientist here at the Southwest Research Institute's Department
of Space Studies in Boulder. He serves on the foundation's board of
directors.

At first blush, Chapman advises, it might seem easy to move a small
asteroid. "An elementary physics equation -- force equals mass times
acceleration -- would seem to guarantee that if you pushed on the 'space
rock,' it would move. But asteroids are much more complex than that," he
told SPACE.com.

There's need for practice, Chapman said. Learning how to despin an asteroid
before pushing is a likely priority. Coming up with ways to anchor a
low-thrust device firmly to a small, nearly gravitationless body is another
factor. No telling what kind of surface an asteroid might have, be it sandy
or fluffy, maybe rocky or metallic.

"Solving such problems will involve both improved scientific understanding
of asteroids as well as technology development," Chapman said. "It is too
early in developing the concepts for Project B612 to know just how much more
science is needed, and how it must be phased as the project proceeds. But I
expect that the science and technology will proceed in tandem," he said.

Surprises in store

Similar in view is Dan Durda, also a Southwest Research Institute space
scientist. "The best way to learn how to work around and on a small asteroid
is to actually try to do it," he said.

Durda said anticipating what might occur on an asteroid by extrapolating
from past space experiences is somewhat limited. "Until you actually press
onto the real thing you have no way to know what environmental and
operational surprises may be in store," he said.

Chapman said that on-going ground-based, Earth-orbit based, theoretical, and
up-close spacecraft studies of comets and asteroids will help those involved
in the B612 work to better recognize challenges as they progress toward
their central goal.

Such complexities as 'rubble pile' compound of Near Earth Objects, asteroids
orbited by natural satellites, 'tumbling' rotations, and questions about
presence or lack of top surface materials on small bodies - all make the
task of moving such objects "a fascinating challenge," Chapman said.

Face the public

Also on the B612 Foundation board of directors is NASA astronaut, Edward
Tsang Lu. He is assigned to the Expedition 7 crew that was to occupy the
International Space Station in March.

Another board member is Geoffrey Baehr of the venture capital firm, U.S.
Venture Partners in Menlo Park, California, as is Piet Hut, Professor of
Interdisciplinary Studies at the Institute for Advanced Study in Princeton,
New Jersey.

Astrophysicist Hut underscored his keen interest in asteroid deflection work
in a letter to U.S. President Bush last December.

"Would you be willing to face the public if an asteroid would be discovered
heading our way? You would have to tell them that NASA has been discovering
and tracking asteroids, but that funding had not been sufficient to
catalogue most of them, and that there had not been any funding so far to
study the question of how to deflect an asteroid, once found, even though
the technology has in principle been available. Not a nice speech to give, I
bet," he advised the U.S. President.

White House legacy?

Hut said the technological ingredients to prod a 328-feet (100-meter)
diameter asteroid so it will miss Earth are at hand. A test mission, he
said, could demonstrate the ability to do so.

"That way, when we discover an asteroid with our name on it, so to speak, we
will be prepared. We could be in a position to save millions of lives, and
at the very least we could not be accused of knowing about a danger and
ignoring it," Hut wrote.

"Even if we are lucky, and no life-threatening asteroid crosses our path in
the foreseeable future, developing the technology to gently nudge asteroids
is likely to help us to explore the solar system," Hut counseled the
President.

"This could be a major legacy of your administration," Hut's letter to the
White House concluded, "to open the door to populating other worlds while at
the same time making our own world a safer place."
Received on Wed 05 Feb 2003 11:53:42 AM PST