afternoon when telemetry pointed
to an electrical short in the pyrotechnic relay needed to release
the arrays.
In Mission Control, off-duty flight
director Phil Shaffer set to work
implementing a malfunction list to
handle the myriad problems which
were now flooding in from Skylab. “Puddy didn’t have time for
it,” Shaffer related, in an interview
quoted by David Hitt, Owen Garriott and Joe Kerwin in their book
Homesteading Space. Within an
hour or two of starting the list, Shaffer found that it already ran to nearly 50 mission-critical items! “At that
point,” he continued, “we stalled
out on the post-insertion activation
sequence…and stuff just kept failing and we could see it was beginning to get hot inside Skylab.”
It was certain that Charles ‘Pete’
Conrad (Commander), Joe Kerwin
(Science Pilot) and Paul Weitz (Pilot)
would not be flying on 15 May and
their launch was scrubbed within
eight hours of Skylab reaching orbit. Based on the station’s orbital
geometry, launch opportunities
occurred every five days and the
mission was tentatively rescheduled for no earlier than 20 May. The
astronauts flew back to Houston
in their T-38 jets to develop a new
flight plan, which called for a 17day ‘nominal’ mission, then ‘minimal activity’ for a further 11 days in
order to gather the medical data
for a full four-week residency.
However, as this plan began to
crystallise, the situation worsened.
In order to produce electricity,
Skylab needed to remain in a ‘solar inertial attitude’, with the Sun’s
rays perpendicular to the ATM solar panels, but this exposed the full
length of the workshop to excessive
overheating.
For a time, Mission Control limited
the problem by pointing the front
‘end’ of the station dir ectly at the
Sun. This lowered temperatures...
but also reduced power levels. The
best compromise, it was found, was
for Skylab to be pitched ‘upwards’,
about 45 degrees, towards the Sun.
This permitted just enough sunlight
to illuminate the ATM arrays and
34
34
Artist’s concept illustrating cutaway view of Skylab 1 Orbital Workshop (OWS).
Illustration: NASA via Retro Space Images
charge their batteries for the next
period of orbital darkness, whilst also
stabilising internal temperatures
at around 42°C. Conversely, and
somewhat ironically, temperatures
in the airlock actually dropped precipitously and threatened to freeze
heat exchangers and coolant loops
by 18 May. Manoeuvres to warm
the airlock succeeded, but at the
expense of overheating the rest of
the station. Therefore, the problem
of maintaining this fine balance
between temperature and power
was extremely difficult.
Although it was clear that some
sort of repair was critical, there was
one saving grace: not all of Sky-
lab’s exterior required protection. In
fact, covering the part of the workshop’s exterior which directly faced
the Sun would serve to bring temperatures within satisfactory limits
and, furthermore, such a ‘shade’
would not need to be tied down or
composed of strong or rigid material. In the hours after the accident,
options for developing this material were exhaustively brainstormed
throughout NASA and the proposals
came thick and fast, ranging from
spray paints, inflatable balloons
and wallpapers to window curtains
and extending metal panels.
At length, ten options were shortlisted for closer inspection, within
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