MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
Contact: Martha J. Heil, (818) 354-0850
FOR IMMEDIATE RELEASEJanuary 11, 2000
STARDUST CAN SEE CLEARLY NOW -- JUST BEFORE EARTH FLYBY
After a few months of foggy camera vision, NASA's
Stardust mission team has improved the spacecraft's
navigation-camera resolution to nearly normal, just as
Stardust is preparing to make a close flyby of the Earth on
By heating the camera's optical path, the Stardust
team was able to help its nearsighted spacecraft boil away
contaminants that had been deposited on optical surfaces.
One year ago, the imaging team took pictures of a
small lamp inside the optical path of the camera. The
camera will be used to navigate Stardust to its 2004
encounter with Comet Wild 2 (pronounced "vilt-2"). Apparent
contamination of the navigation-camera prevented a clear
test-image of the squiggly line of the lamp's filament, and
the lens seemed to be covered with a veil of light-
scattering material that produced a blurry image.
The team concluded that the contamination might have
been released with gases escaping from the spacecraft after
its launch, and that heating the optical path of the camera
might evaporate the contaminant covering the camera lens.
After a series of heating cycles, they re-tested the camera
by taking more pictures of the lamp.
Pictures taken after the heating revealed that the
zigzag line of the lamp's filament was visible again.
Images of stars taken by the camera are also clearer. The
team estimates the camera can now photograph stars two
magnitudes (celestial degrees of brightness) better. The
navigation camera has detected stars as faint as 9th
magnitude in brightness, which should allow the spacecraft
to perform its final navigation maneuvers during approach
to the comet nearly at the time originally planned.
Now Stardust, on its journey to collect comet dust, is
getting ready to springboard from Earth -- in a maneuver
called a "gravity-assist" -- when the spacecraft passes
closest to Earth on January 15, 2001. The Earth will not
be in the navigation camera's field-of-view during the
flyby, so no images of Earth will be taken.
Stardust was launched on February 7, 1999, into its
first loop around the Sun. When Stardust passes by Earth at
about 10 kilometers per second (22,400 miles per hour), it
will go into a slightly wider orbit that will allow it to
reach the comet on January 2, 2004.
On Monday, January 15, Stardust will fly by a point
just southeast of the southern tip of Africa, slightly more
than 6,000 kilometers (3,700 miles) from the surface at
about 3:15 a.m. PST (6:15 a.m. EST).
Stardust may be visible to observers using
sophisticated telescopes with charge-coupled device (CCD)
detectors from the Pacific Ocean and the Western United
States just after the spacecraft flies by Earth. Stardust
will not be visible using binoculars.
A gravity-assist works like this: when a spacecraft
closely approaches a planet, the planet's gravitational
pull accelerates the spacecraft and bends the flight path.
Mission designers account for this extra pull and use it to
their advantage to boost spacecraft speed and direct
interplanetary spacecraft to their targets. Like a windup
before the pitch, the Earth gravity-assist will sling
Stardust into the right path to meet Comet Wild 2.
About 15 hours after its closest approach to Earth,
the spacecraft will pass about 98,000 kilometers (61,000
miles) from the Moon. Because of the greater distance, the
Moon's gravity will have essentially no influence on the
spacecraft's flight path.
Stardust, a part of NASA's Discovery Program of low-
cost, highly focused science missions, is managed by the Jet
Propulsion Laboratory (JPL), Pasadena, Calif. for NASA's
Office of Space Science, Washington, D.C. JPL is a division
of the California Institute of Technology, Pasadena. More
information on the Stardust mission is available at
NOTE TO BROADCASTERS: Interview clips and B-roll to
accompany this release are being carried on NASA Television,
GE-2, Transponder 9C at 85 degrees West longitude, with
vertical polarization. Frequency is on 3880.0 megahertz
with audio on 6.8 megahertz. For broadcast times, see
ftp://ftp.hq.nasa.gov/pub/pao/tv-advisory/nasa-tv.txt. Live shots are available Friday, Dec. 12 from 5 p.m. to 9
p.m. Eastern Time.
To arrange a live shot, contact Jack Dawson at