Water was used for many purposes in the shuttle.
The particular application you are asking about is the Water Spray Boiler (WSB), part of the Auxiliary Power Unit / Hydraulic (APU/Hyd) system. This device provided cooling to the lubrication oil in the APU and to the hydraulic fluid as required. Each of the three APU/Hyd systems had a dedicated WSB.
The spacecraft is lost if no DC power is available.
That was indeed true.
A subset of the shuttle electrical busses were redundantly powered so that loss of one or, in some cases, even two fuel cells did not mean that the bus lost power. An example of the triply redundant busses were the "essential busses".
These busses were required to switch ...
Ooh, this is old.
I do feel the answers need a little addition though:
Why would NASA not choose to go with their conceptual design when building the ISS,
See below, but TL;DR: Russia coming on board and Mir-Shuttle docking experience killed off the design.
and how would it have worked?
See below. NASA patented a concept of its operation.
The two ...
No. Even the highest ballistic coefficient debris (engine turbopumps, etc) only made it to Louisiana.
Heavier objects with
higher ballistic coefficients, a measure of how far objects will
travel in the air, landed toward the end of the debris trail in
Source: CAIB Report Volume 1 p. 45 & 47
Unlikely. From the Wikipedia page on orbital decay:
Due to atmospheric drag, the lowest altitude above the Earth at which an object in a circular orbit can complete at least one full revolution without propulsion is approximately 150 km (93 mi) while the lowest perigee of an elliptical revolution is approximately 90 km (56 mi).
70.5 km is well below that. ...
Just created a new account to comment here, but apparently I need more reputation to comment direction on a previous post... I just wanted to chime in that Ludo is correct, that patent, co-authored by my grandfather "George von Pragenau" is indeed what was used for the Saturn V dynamic test stand. He was the dynamic stability guru for NASA during ...