Missives from Mission Control: Final Report

Eyewitness reports from the final Hubble Space Telescope Mission

On Monday, May 18, Astronauts John Grunsfeld and Drew Feustel began the final spacewalk an hour ahead of schedule, determined to see all repairs were completed; including on which had been delayed by difficulties with a stubborn screw the day before. Dr. Ed Cheung, Principle Engineer of the Hubble Service Project, normally working out of Goddard Space Center, had been stationed at Kennedy Space Center with his team for months prior to launch and after at Johnson Space Center walking the astronauts through the practice for and actual repairs. He has been sending his daily eyewitness reports back to his native island of Aruba to share this great adventure with his countrymen. Dr. Cheung confirms this final Extra-Vehicular Activity, EVA 5 completed the required repairs and installation of new equipment, and the Atlantis crew will be heading home. A misstep by Astronaut Grunsfeld resulted in small piece of the HST antennae breaking away, but scientists on the ground report no disruption in communications with the science platform.
Dr. Cheung writes: “Today is the last EVA day. We installed a new Fine Guidance Sensor (FGS), the second new battery, and several door blankets (NOBLs.) I was not involved in the development of this equipment.”

“The FGS is used to lock Hubble onto a target.  Whenever a science observation is scheduled, two guide stars are selected near the target.  These are bright single stars with known locations.  When Hubble is moved to acquire a target, it looks for those bright stars, and ‘locks onto’ them.  It then directs its attitude control system to keep those stars in precise view.  If they should appear to move, the control system moves the vehicle to keep them in the same spot.  This is one of the reasons Hubble is so stable.  There are three FGS’s on Hubble, and two have been replaced (one is still original).  Installation of the new unit encountered the same problem as WFC3: the old bolt did not want to release (seems to be a common problem), but it was handled the same way, and no further problems occurred.  The new one passed all tests”

“The NOBLs are new blankets for the small doors on Hubble.  The old insulation has deteriorated due to so many years of sun exposure, and this impacts the electronics inside.  One of these doors holds the data transmitter to the ground.  If this overheats, we would have a big problem.  Currently, we manage this by turning the transmitter on and off.  With all the new instruments, it would be a shame not to get the images down to the ground, so a new blanket was essential.  Our lead spacewalker, John Grunsfeld, knows this, and you could tell in last night’s conference with the Flight Director, how driven he was to install all three NOBLs.  We felt great when hearing the determination in his voice.”

“To cut to the ending….today’s space walk went extremely well.  It took John and Drew only 4 1/2 hrs to finish the two main tasks.  They were then able to install all three new blankets.  We had always planned on installing only one this day.  But their hard work allowed us to do all three.  After doing all this to benefit to Hubble, John had a small accident just prior to coming back inside.  He knocked the very tip off the communications antenna; this is underneath Hubble.  This was no big deal, but they installed a protective cover that was onboard just for this eventuality.  While John was coming back in, he said “Sorry Mr. Hubble”.  I get emotional just thinking about this.  He has done so much for Hubble, and I hope he won’t beat himself up over this.  We all know how much Hubble means to John, being the only astronomer-astronaut to work on her.”

“Tonight we had a few short social events in our control room at mission control.  The wives of some of the astronaut crew came in and presented us with a cake in the shape of Hubble.  It was nice sharing it with them.  “I won’t miss the long hours or travel away from home. However, I will miss coming to work and seeing the Shuttle everyday on the drive in; the excitement I felt these past few months and during my time at Kennedy Space Center; having the security clearance to be able to go into the Orbiter any time I wanted to; having lunch or dinner with my work buddies every day; the quiet times at Mission Control when I can write these notes; the busy times at Mission Control when I am trying to solve 2 or 3 problems simultaneously while listening to the loops.”

“Tomorrow we will release Hubble, and say goodbye to her for the last time.  I will probably stay an extra long shift to witness it.  With that, this will be my final update of STS-125.  I have enjoyed writing them for you, and I really hope you have enjoyed reading them.  I am pretty tired of these shifts, and ready to go home, but I know that after a few days there, I will look back at this whole mission, and realize how much I wish I could do it again.”