Mission Update - January 2005
Background from Keyur Patel - Deputy Project Manager
Author: Maura Rountree-Brown - Education and Public Outreach
The Deep Impact twin spacecraft made a long, slow journey from Astrotech to the launch pad at Cape Canaveral on
December 3rd. The five-hour journey was the last transport of the spacecraft while on Earth. Now on the launch pad, atop the
Boeing Delta II rocket that will carry them to space, the spacecraft is going through a series of "pad functional" tests. If you
have been following the Deep Impact mission, you know that some tests are repeated each time the spacecraft is moved. After
that, the spacecraft will go through "battery management" to charge the flight battery, which is not as easy as charging the
battery on your car or camera. A final checklist of closeout details will be run.
Twenty-four hours before launch (L-24), the team will begin countdown procedure. Communications between Astrotech
and Jet Propulsion Laboratory (JPL) are confirmed because they must be working properly before launch efforts can continue.
The communication reaches the spacecraft through an umbilical cord, much as a mother supports an unborn child before birth.
A last minute break in communication with any one would mean a cancelled attempt and a re-schedule of the launch. Although
the spacecraft sits on a launch pad at Cape Canaveral, Florida, Jennifer Rocca, the Project Launch Flight Director will orchestrate
the launch procedure from Los Angeles, California at JPL to KSC and Astrotech.
You may have seen a movie of a rocket launch but you might not be aware of all the milestones the project team is
reaching to call the launch successful. Here is what will happen during the first hour of launch. During the launch, the umbilical
cord to the spacecraft will be pulled away as the rocket ascends and the team will lose contact with the spacecraft for
approximately 47 minutes.
At approximately launch plus 1 minute (L+65), the solid rocket boosters will be ejected from the rocket. At
approximately L+5 minutes, the fairing (stage one) will fall away from the rocket. Approximately L+29 minutes seconds will cue
the second stage of the rocket to eject. And finally, at approximately L+2125 seconds, the last part of the rocket (third stage)
will fall away. At approximately L+35 minutes the spacecraft will warm up and begin an internal launch sequence that allows it
to send a signal to the Deep Space Network at Canberra, Australia and the team will first hear from the spacecraft at
approximately L+47 minutes. A launch is considered successful if all these steps take place and they hear the spacecraft greet
them from space.
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