Hubble Servicing Mission 3A Update - Dec. 24-25 Day 5

The third spacewalk of Servicing Mission 3A was also performed flawlessly. The tasks on this spacewalk included finishing the installation of the fine guidance sensor, which was installed during the second spacewalk, together with replacement of a faulty radio transmitter and a data tape recorder. Additionally installation of thermal insulation was on today's to do-list for the astronauts.

Within the first hour of leaving the air hatch astronauts Grunsfeld and Smith had installed an optical control electronics package for the fine guidance sensor. They immediately moved on to the rather difficult task of replacing the S-band radio transmitter. This unit failed in 1998, but the other transmitter has so far been able to handle the communication tasks alone. The unit was never meant to be changed in space and John Grunsfeld required all his concentration to remove small bolts and connectors wearing the big gloves of his spacesuit.

Amazingly the work went smoothly and the team pressed on with the installation of a new solid-state data recorder that replaced the old reel-to-reel tape recorder. Again there were no problems and initial tests of both the transmitter and recorder showed no problems. The new recorder not only uses better technology (solid state memory chips) for storing the observation data, but it will also be able to store 10 times more data (1.5 Gbyte). The ability to simultaneously record and play back data, in addition to having access all data at once makes this recorder a big improvement taking Hubble into the new millenium.

The last work to be done was the replacement of thermal insulation on Hubble's outside. Time constraints meant that the work had to stop after installation of insulation on two of the equipment bays, but still the accomplishments of this servicing mission are truly outstanding!

It now seems that Hubble will not only be able to work again after more than two months of downtime, but will be able to work much more efficiently than before. Final tests will be carried out before Hubble's release Sunday 26 December at 00:03 CET.