At
about 8:39 p.m PST on February 14 2011, NASA’s spacecraft, the
Stardust, completed what seems to be its closest flyby to the comet
Tempel 1. NASA estimates the spacecraft came to within about 182
kilometres or 112 miles from the the comet.
About 1 hour after the spacecraft’s flyby, the Stardust turned its
large, high-gain antenna towards earth to begin transmission of the
images it captured during the flyby. This is labelled as a bonus mission
for the spacecraft, which has been dubbed a comet chaser, as it
originally flew past comet Wild 2 and returned samples from its coma
back to earth. With this bonus mission, the spacecraft was to capture
images of the comet’s surface to see what has changed since the craft
last visited the comet. The previous encounter with the comet was back
in July 2005, using NASA’s Deep Impact spacecraft.
Stardust-NExt is a low cost mission designed to expand the
investigation of comet Tempel 1, which was initially started by NASA’s
Deep Impact spacecraft.
A year ago, NASA’s Stardust spacecraft performed the largest rocket
burn of its life, with the rockets firing for 22 minutes and 53 seconds.
This changed the craft’s speed by 24 meters per second or (54 mph). The
idea was to determine which side of the Tempel 1 comet would face the
sun when the craft passed it by.
“Our goal is to re-visit a comet to look for changes that occurred
since NASA’s Deep Impact mission took a look five-and-a-half years ago,”
said Tim Larson, Stardust-NExT project manager from NASA’s Jet
Propulsion Laboratory in Pasadena, Calif. “We may also see the crater
that Deep Impact created in 2005, but because of Tempel 1′s rotation,
there is no guarantee. At the end of the day, whatever we see there
should provide some great new science.”
Since 1984, only flybys of six comets have been completed. The only
spacecraft with the ability to see if any changes have occured during
the comet’s lifetime, is the Stardust-NExt.
The total weight of the spacecraft, including the fuel needed for
deep space maneuvers is 380 kilograms, with the overall length of the
main bus being 1.7 meters.
The STARDUST-NExT spacecraft encountered comet Wild 2 early in 2004
and collected samples of cometary dust and volatiles while flying
through the coma at a distance of approximately 250 km on the sunlit
side of the nucleus. The samples were returned to Earth for analysis in
2006.
Using low-density silica aerogel, the craft collected particles from
the comet during the original Stardust mission, using a return capsule
which was jettisoned back to earth in January 2006. The navigation
camera is also used to provide high-resolution science images of the
comet.
Artist’s concept of NASA’s Stardust-NExT mission, which
will fly by comet Tempel 1 on Feb. 14, 2011. Image credit:
NASA/JPL-Caltech/LMSS
This image shows comet Tempel 1 approximately 5 minutes
before Deep Impact’s probe smashed into its surface. It was taken by
the probe’s impactor targeting sensor. Image Credit:
NASA/JPL-Caltech/UMD