Originally posted by RFBurns
There could have been an attempt to retrieve it, the thruster packs would have enough fuel to manuver to it and manuver back, since both themselves
and the toolbag are moving along at the same speed.
I disagree. Obviously the bag was floating away so they were not moving at the exact same speed. Therefore, you need additional speed to overtake
the bag in a timely manner and still return to the station structure with fuel to spare. The problem is, the SAFER system only provides about
10ft/sec delta-V. That's the same about the same as the speed of a one second drop on earth. Also, the SAFER system is not redundant at all since
it is a last resort - astronauts are always double tethered to the station structure so SAFER was considered to be the third and last line of defense
with no further redundancy.
The thruster pack adjusts for attitude control, but it is not designed for prolonged travel use.
Indeed, in fact it's designed specifically as a last resort and is not certified for use except when the astronaut's safety is at greater risk if it
is not used.
An astronaut could have teathered themsevles off, give themselves a little push off the ISS towards the toolbag, grab it, attach it to another teather
belt that the astronaut brings with him/her, and then simply pull himself/herself back to the ISS on the teather they are attached to.
They're always doubly tethered, but I'm not sure the tether length would have been enough, once they were sure it was truly safe to push off, to
allow them to reach the bag. I also doubt that mission control would have allowed them to conduct such a "test" of the tensile strength of the
tethers. In theory, yes they should hold when the astronaut goes to yank on the tether to bring them back, but on the other hand it could come loose,
at which point the unfortunate astronaut has only one option left with a mere 10ft/sec delta-V to play with.
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