Missives from Mission Control - Murphy’s Law Strikes Again!

Eyewitness accounts of the final service mission to the Hubble Space Telescope

Servicing Mission (SM 4) is now four days done, and astronauts John Grunsfeld and Andrew Feustel have completed the first of five space walks to service and upgrade the Hubble Space Telescope 350 miles above the earth. The two priority jobs, replacement of the science computer and installation of the Wide Field Camera 3 (WFC3) are now completed. The removal of the WFC2, which served scientists for sixteen years and provided some remarkable images, proved not so simple a task as anticipated.

Dr. Ed Cheung, born in Aruba, holds the position of Principle Engineer of the Hubble Space Telescope Service Project, and was the designer of the WFC3, which he spent eight years perfecting. In his latest daily update from mission control at Johnson Space Center in Houston, Texas, he explains that a long day of unexpected difficulties made the tasks of installing these two vital pieces of equipment as “harrowing.”

“Today we had our first day with space walks.  EVA Day 1 (Extra-Vehicular Activity Day 1).  On this day, we installed the WFC3 and SIC&DH. It will be the next premier imaging instrument for Hubble.  Compared to the one it is replacing (which has only about 2.5 Megapixels), the new camera will have 16 Megapixels.  More importantly, it can see a wider range of colors, from infrared to ultraviolet.  It will be like opening our eyes for the first time to colors and details we have never seen.”

“The SIC&DH is the science data computer that failed last year, and caused the delay in the mission.  At the time, we switched to the backup unit that had been in space for 18 years waiting for its turn.  However, NASA management decided we would not risk another failure that would render Hubble completely useless as a science instrument.  I happen to be Electrical Lead on both of these items, and they were on the first EVA day due to their priority.  WFC3 was first.  Well, it did not go smoothly.  We had major problems getting the old instrument (WFPC2) out.  To remove the instrument, the astronauts needed to turn one bolt.  Well it did not turn at all!  They had to change tools to apply more and more torque.  It got to the point where they could snap the bolt in half by applying more than 50 ft-lbs of torque.  If that occurred, we would never be able to remove the old instrument to put in the new one.  This was extremely harrowing (to say the least).”

“Due to my shift schedule, I watched this all unfold in my hotel room.  I had access to the live TV from space, and communicated with my teammates via a chat program.  While this was all unfolding, we were all getting very anxious, including me.  When all options were exhausted, and the astronaut approached with the big wrench, we were all hoping for the best.  When Drew Fuestel finally turned the bolt, and it turned, we did not know if the bolt broke or not.  He then reported to our relief that he said that it felt like it was turning, and not broken!  There was applause in the control rooms back home in Maryland and in Texas.  Prior to that, I could not believe that this was happening.  After years of work, and careful planning, a single bolt almost caused it all to go to waste.  So far, our tests of the new camera are good.  The tests will continue through the night.”

The WFC3 should soon start delivering remarkable images of space never observed by scientists before. Literally, the camera is a “time machine,” as the images will be from celestial bodies so distant that scientists will be watching events that have taken places centuries and millennia past, because of the time it takes for light to travel to the Hubble. More space walks and repairs continue today, with the hope that all goes smoothly, but prepared for perhaps another “harrowing” day.

Story by Rosalie Klein