NASA Deep Impact Mission Update – April 2005

Maura Rountree-Brown with information from Mike Sierchio, Deputy Mission Manager

The Deep Impact mission team closed the Commission Phase of flight with the completion of the impactor projectile’s checkout activities. During that phase, the team verified the basic health of all subsystems and tested the operation of the science instruments.

The mission now moves to Cruise Phase. During the coming months, the team will work toward updating the attitude control system tables that control the alignment of the spacecraft instruments, which refines the ability of the spacecraft to accurately point the onboard instruments at Comet Tempel 1.

The High and Medium Resolution (HRI and MRI) instruments on the flyby spacecraft are fixed in position so a period of testing and rehearsing takes place as the team asks the spacecraft to focus on a star and center it. By updating the software that commands the spacecraft’s attitude control, the team finds the best X and Y axis position for the spacecraft to center on Comet Tempel 1. It’s a little like buying a new camera and then learning how to take the best pictures by learning the actual parameters of that instrument. The science team will conduct instrument calibration tests using a set of stars, further verifying imaging procedures for encounter.

The High Resolution Instrument has not reached perfect focus and the team is investigating how to bring it to its best performance level. The HRI’s current performance, combined with that of the Medium Resolution imaging and IR spectrometer on the flyby spacecraft and the Impactor Targeting Sensor on the projectile, still gives the mission’s PI, Dr. Mike A’Hearn the confidence that images taken of Comet Tempel 1 will be the most detailed of a comet nucleus ever taken. View the latest press release. http://deepimpact.jpl.nasa.gov/press/050325nasahq.html