Proves Wide-Band Doppler Can Track Debris
Radar tracking data gathered during the Delta II launch of the
MESSENGER spacecraft earlier this month has provided promising
results that may benefit NASA's Space Shuttle Program and
Discovery's Return to Flight.
A pair of radars installed at NASA's Kennedy Space Center (FL)
at a site north of Haulover Canal tracked the launch phase of the
Delta II, including separation of the nine solid rocket boosters
and jettison of the first stage and the payload fairing, the "nose"
of the rocket that protected the MESSENGER spacecraft during
launch.
"This test was quite successful for us in proving a concept,"
said NASA project manager Tony Griffith. "The use of
high-resolution wide band and Doppler radars allows us to observe
almost any possible debris during ascent and means we can observe
the Space Shuttle without regard to limitations of visibility,
cloud cover and darkness."
More importantly, the tandem radars "saw" -- in significant
detail -- ice shedding from the Delta first stage, ejection of the
solid rocket booster nozzle throat plugs, and contents of their
exhaust. These are normal Delta launch events. For the Space
Shuttle Program, the test showed that the radars, working together,
were effective in visualizing the vehicle elements in high
resolution and the ability to attain speedy interpretation of the
images for initial data analysis after a Shuttle launch.
The antennas have been on loan to NASA from the USNS Pathfinder,
a US Navy instrumentation ship. The 30-foot-diameter C-band
wideband radar antenna and the smaller X-band Doppler radar worked
together to image the Delta in flight. The Navy operated the radars
for NASA during the MESSENGER launch. NASA was responsible for
analyzing the imagery.
"This turned out to be a successful and mutually beneficial
partnership with the Navy that we will pursue," Griffith said.
Later this fall, a 50-foot-diameter C-band wide band radar will
be installed on this site for a similar Return to Flight
application and for use by the Navy. The radar is being relocated
to KSC from the Roosevelt Roads Naval Station in Puerto Rico.
The radars used for the test are being returned to the USNS
Pathfinder, though the C-band radar used in this test could return
as a backup for Return to Flight, if available from the Navy. NASA
is evaluating the procurement of two X-band Doppler radars for use
on ships downrange, including one of the solid rocket booster
retrieval ships.