NASA approved development of a robotic spacecraft
mission that reads more like a story line from a science
fiction movie script. Imagine intercepting a comet in deep
space and using a heavy projectile to blow a hole in the
celestial body, some seven stories deep and about the size of
a football field.
In a space exploration first, NASA’s Deep Impact Mission will
attempt to use a probe to collide with a comet in an attempt
to peer beneath its surface. Scheduled for launch in January
2004, the unique spacecraft is expected to arrive at comet
Tempel 1 in July 2005.
Researchers hope the impact will allow them to measure
freshly exposed material and study samples hidden deep below
the surface of the comet, which could yield dramatic
scientific breakthroughs.
The 770 pound impactor, equipped with a camera, will separate
from the flyby spacecraft and slam into the comet at an
approximate speed of 22,300 miles per hour, blasting material
from the comet into space with the force of its impact. A
camera and infrared spectrometer on the flyby spacecraft,
along with ground-based observatories, will study the
resulting icy debris and exposed pristine interior material.
The total cost of Deep Impact to NASA is $279 million. The
principal investigator, Dr. Michael A’Hearn, University of
Maryland, College Park, will lead a team consisting of NASA’s
Jet Propulsion Laboratory in Pasadena, CA, and Ball Aerospace
Technology Corp., Boulder, CO, which will build the
spacecraft.
Comet Tempel 1 was discovered in 1867. Orbiting the sun every
five and a half years, it has made many passages through the
inner solar system. This makes it a good target to study
evolutionary change in the mantle, or upper crust, of the
comet.
Scientists are eager to learn whether comets exhaust their
supply of gas and ice to space or seal it into their
interiors. They would also like to learn how a comet’s
interior is different from its surface. The controlled
cratering experiment of this mission could provide those
answers.
NASA’s Discovery Program emphasizes lower-cost, highly
focused scientific missions within the Space Science
enterprise. NASA has developed six other Discovery Program
missions. Three have completed their missions, one is
operational and two others, in addition to Deep Impact, are
under development:
* In 1997, the Mars Pathfinder lander, carrying a small
robotic rover named Sojourner, landed successfully on Mars
and returned hundreds of images and thousands of measurements
of the Martian environment.
* The Near Earth Asteroid Rendezvous (NEAR) spacecraft
orbited the asteroid Eros for a year, ending with a
successful landing on February 12, 2001.
* The Lunar Prospector orbiter mapped the Moon’s composition
and gravity field and completed its highly successful mission
in July 1999.
* The Stardust mission to gather samples of comet dust and
return them to Earth was launched in February 1999, and is on
its way to comet Wild-2.
* The Genesis mission to gather samples of the solar wind
and return them to Earth is scheduled for launch on July 30,
2001.
* The Comet Nucleus Tour (CONTOUR) mission to fly closely by
three comets is scheduled for launch in June 2002.
More information on the Deep Impact mission, including images
and animations of the impact, is available on the Internet
at:
http://deepimpact.jpl.nasa.gov/
