fisher@dvinci.DEC (Burns Fisher, MRO3-1/E13, 231-4108) (04/12/84)
1) Re fuel: My understanding was that the fuel problem was in the forward
RCS system (i.e. the attitude jets), not the OMS (orbital maneuvering system)
engines. This problem was caused by all the station-keeping with Solar
Max which was done on Sunday during the first unsucessful attempt to grab
it.
2) Re Ground Control stabilization:
2.1 The Boston Globe (via wire service?) reported that Goddard had
actually managed to bring Solar Max to a stop between Sunday
and Tuesday, but that Houston requested that it be respun (at
about .5 the rate it originally had) because (a) that was how
the astros had practiced a non-MMU grapple, and (b) the thing
might have been stopped with the grapple pin pointed away from
the direction from which the shuttle was rendezvousing. Rotation
meant that the shuttle could just wait for it to come around
rather than wasting fuel to move around the satellite
2.2 Someone at a shift-change news conference asked the question
of why they used the MMU to begin with. The answer was (a)
they wanted to have several options available, and (b) with the
MMU, they would have had a lot more control of the craft. In
addition, at another time it was stated (somewhere) that the
ground spin-down was rather risky because they had to use
electromagnetic torqueing against the earth's mag. field. This
required a LOT of power, and since the solar cells weren't pointed
properly at the sun, there was danger that Solar Max's batteries
would run down. They lucked out in that the batteries lasted long
enough for them to both get the rotation/wobble slowed and get the
s-cells pointed sunward.
3. The TPAD problem: Again in the Globe, it was reported that Solar Max
had a small pin holding its insulation on which has close to the trunion
pin. This pin could have interfered with the TPAD.
Burns Fisher
UUCP: ... {decvax|allegra|ucbvax}!decwrl!rhea!dvinci!fisher
ARPA: decwrl!rhea!dvinci!fisher@{Berkeley | SU-Shasta}