from the old camera which needed
more torque than they thought
would be required.
Feustel achieved the torque required with the aid of a torque limiter
that fortunately had been thought of
and stored back in the airlock. The
great worry was that the bolt holding
the WFPC-2 would sheer and break
thus not allowing it to be removed,
that would have been disastrous, but
the ground team gave Feustel the
go ahead to apply as much force
as he thought it would take and to
everyone’s relief in came out, job
done!
Once they had installed the new
WFC-3, which will allow Hubble to
see farther into space and across
a wider spectrum of colours, they
connected it up to power, teams at
Goddard Space Flight Centre sent
commands to the unit to see if it was
“alive and awake”, fortunately it
was, and that indicated that the EVA
team had installed it correctly, task 1
had been completed.
Back in September 2008 when the
STS-125 mission was being prepared
for launch, one of the computers
on Hubble failed. This was the Science Instrument Command and
Data Handling Unit, or SIC&DH that’s
used to send data to Hubble’s instruments and then formats it ready for
transmission to the ground. This was
replaced and the final EVA task for
day four got under way, installation
of what is termed the Soft-Capture
Mechanism (SCM).
Second and third EVAs
Good news on day 5, the ground
crew informed the crew that the
WFC-3 had passed all the overnight
tests, indicating that it was in good
working order, a great result for EVA
1.
Now though it was the turn of Massimino and Good.
The first task for EVA 2 was the removal and replacing Hubble’s three
gyroscope rate sensing units (RSUs).
Each unit contains two gyroscopes
that allow the telescope to point
itself. The first unit was replaced
without any issues but when they attempted to replace the second unit,
RSU 3, the unit would not align onto
the guide pins, and they could not
get it to sit correctly into the vacated
bay, so ground managers had to
come up with a solution. It was duly
decided that the best way forward
would be to put the RSU unit originally intended for the number one
bay into the 3rd bay, fortunately that
worked, but he problems were not
over yet, after attempting to install
the second unit into the third and last
bay this one would not now seat correctly in place and in the end they
gave up trying.
It was then decided to use one
unit that was carried as an additional
fight spare. This one was originally re-
it was down to the serious business of
EVA number 3.
Today’s tasks for John Grunsfeld
and Andrew Feustel started with one
that was deemed to be one of the
most challenging of the mission and
certainly one of the most uncertain in
terms of it going to plan and working,
but these task were considered to be
very important, some of the most important of the entire STS-125 mission.
The first job was to remove the
now unused Corrective Space Telescope Axial Replacement (COSTAR),
this as you will recall was the set of
mirrors that corrected Hubble’s vi-
Andrew Feustel, positioned on a foot restraint on the end of Atlantis’ remote manipulator system (RMS), moves
the Corrective Optics Space Telescope Axial Replacement (COSTAR) during the mission’s third EVA session to
refurbish and upgrade the Hubble Space Telescope. Credit: NASA
moved during STS-103 and had been
taken back to Earth and refurbished,
not ideal but at least it worked. This
was a critical series of installations
tasks for the mission critical to Hubble’s survival in orbit. Three sets of gyros had already failed to work in the
past so replacement was essential
for the longevity of the telescope.
Massimino and Good them moved
on to the batteries and replaced
them too, a good day all in all.
Today the crew awoke to the
sound of a song called Hotel Ceppolina by Fuzzbox Piranha played
especially for Hubble veteran John
Grunsfeld but once everyone was up
sions after the near disastrous problem with Hubble’s primary mirror. The
task was to remove this and replace
it with the brand new Cosmic Origin Spectrograph (COS). The COS
is designed to study the large scale
structure in the universe and how
galaxies, stars, and planets evolved
into what we see today.
The next task would be to try to
repair the Advance Camera For
Surveys, (ACS). The ACS had been
a problem for some time, it was installed in Hubble on servicing Mission
3B in 2002 but an electronics failure in
2007 rendered useless the most useful two science channels, now just