Story by Ben Evans
T
he launch of any new spacecraft cannot be regarded as
‘routine’; nor, indeed, can its
inaugural checkout in orbit.
The Skylab orbital workshop was an
entirely new concept for the United
States and a totally different spacecraft, larger, more spacious and in
many ways far more complex, than
any that had gone before.
Yet on the morning on 14 May
1973, a sense of optimism pervaded the Kennedy Space Center, as
the last in a generation of Saturn
V boosters was readied for its journey into space. Visually, it looked
somewhat different to its lunar predecessors, for, instead of possessing
three stages, it had only two, and
in place of what would have been
the final propulsive stage was the
inert Skylab, capped-off by a bullet-like aerodynamic shroud.
With a near-perfect launch record, there was every expectation
that the final Saturn V would perform admirably.
Launch at 1:30 p.m. EST seemed
pleasing, with the vehicle going supersonic a minute after leaving the
pad.
Then, telemetry in Mission Control showed the first indications
that something was amiss. As Dave
Shayler wrote in Skylab: America’s
Space Station, “The data, which
went almost unnoticed, indicated a
premature deployment of the protective micrometeoroid shield and
the No. 2 workshop solar array.” If
it was not simply an instrumentation
error, this signified very bad news for
Skylab. If the micrometeoroid shield
and one solar array had indeed
deployed during the initial boost to
orbit, they were as good as lost and
www.RocketSTEM.org
The Skylab
Space Station
atop a
Saturn V
rocket is
transported
to Pad 39A
in 1973.
Photo: NASA via
Retro Space Images
the very future of the space station
would hang by a thread.
The Saturn flew its pre-programmed ascent profile, with the
second stage taking over when the
S-IC first stage burned out. The five
J-2 engines of the S-II second stage
were automatically commanded
to burn for a little longer than normal in order to compensate for the
additional weight. Within ten minutes of leaving the Cape, the S-II
shut down crisply and the next milestone was for the instrument unit
atop the workshop to ready Skylab
for orbital operations. The shroud
separated and then, at 1:47 p.m.,
electric motors rotated the giant
Apollo Telescope Mount (ATM) out
90 degrees. After it had locked itself into place, the ATM’s windmill
of solar arrays was deployed.
In the euphoria of those first few
minutes, the mysterious piece of telemetry about the micrometeoroid
shield and the workshop’s own solar arrays almost went unnoticed.
Almost…
Within an hour of liftoff, Flight Director Don Puddy reported erratic
signals. The main solar arrays should
have been deployed when Skylab
passed beyond the Madrid tracking station in Spain.
Tensions began to rise in Houston, as NASA managers listened for
news from the tracking station, at
Carnarvon in Western Australia.
The data was confusing. Controllers expected that their monitors
would show the two large solar panels fully deployed and producing
about 12.4 kW, some 60 percent of
the required electrical load. It was
with surprise and dismay, therefore,
that the data indicated that power
levels were much, much lower…at
a mere 25 watts, in fact! The Carnarvon data suggested that the arrays had released for deployment,
but had not fully extended, whilst
temperature signals from the workshop implied that one array had
either been torn away or had suffered severe structural failure, whilst
the other had been released, but
had not properly deployed.
The data from the next few orbits
confirmed a failed micrometeoroid
shield and a power outage owing
to a solar array malfunction. These
concerns were amplified later in the
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