Think of a long term base in space and everyone thinks of the International Space Station
which has been the longest and most successful space program so far. But the hard-learned
lessons that have kept the ISS continuously manned for over 20 years came from our very
first attempt to live in space longer than just a few weeks with Americas first orbiting
space workshop, Skylab. However, Skylab became known more for the
things that went wrong than the things that went right, problems that started just minutes
into its launch and then years later just before it burned up. This is the story of
Skylab and why it’s probably one the most important space mission we’ve ever done.
This video is sponsored by Brilliant Apollo was a great success for both the US
and humanity to take the huge leap from orbiting the earth for a few days to visiting our nearest
celestial neighbour. Now whilst we had shown that we could get
to and land a man on the moon, the total amount of time we had spent in space on each apollo
mission was still very short. The longest mission, Apollo 17 spent just 3 days on the
surface and just 9 days travelling in space. The talk at the time was that this could be
the springboard to visiting other planets and in particular Mars.
This is the equivalent of someone making their first voyage in a sailing a dingy across the
34 km of the English channel and then deciding that the next one would be across the 5000km
of the Atlantic ocean. Whilst the moon is 384,000km away and about
3 days travelling time, to get to Mars takes about 7 months one way and then the same back
again. We had no idea of what living in the weightless conditions of space for well over
a year would do to the human body or if it could be done at all.
Well before we ever got into space, the use of a space station as a staging post for a
trip to Mars had been discussed by Werner Von Braun in his 1952 book “Project Mars”
and up until the 1960s it was thought that a space station of some sort would an important
early step in space exploration. However, the politics of the cold war dictated
that the US should beat the Soviets to the Moon by the end of the decade and the idea
of a dedicated space station was put to one side.
Although the US may have won the race to the moon the Soviets were the first to put a space
station into orbit with the ill fated Salyut 1 in 1971. However, it had to be abandoned
by its Soyuz 11 crew after 23 days due to problems including a fire in and the crew
were killed by asphyxia whilst returning to earth when a valve in their Soyuz capsule
failed and they remain the only people so far to have died in space.
Back in the US, Von Braun who had started out in the 1950s with the idea of a large
rotating space station like that we see in the film 2001, had already worked out plans
which would become part of the Apollo Applications Program to convert the second stage fuel tank
of a Saturn rocket into an orbital workshop and with the cancellation of the later Apollo
missions 18, 19 and 20, it freed up the now spare Saturn’s to create Skylab and also
use the Apollo command & service modules to transport the crew to and from it.
Skylab would fill in the gap between Apollo and the space shuttle which was due in 1979.
It would not only be a laboratory to find out how living in space would affect the human
body, it would also carry the Apollo Telescope Mount and solar observatory to study the sun
in both the Ultraviolet and X-Ray spectrum outside of the earth’s atmosphere, something
that would become prescient of Skylab’s ultimate fate in 1979.
Skylab was launched on May 14th 1973 to be followed by the crew on another launch the
next day but almost immediately it ran into problems when the micrometeoroid shield / sun
shade accidentally deployed during the launch which was immediately ripped off by the slipstream
as it travelled at several thousand km per hour.
Once in orbit and within an hour of the launch more problems became apparent, with no heat
shield the temperature of the workshop was rising dramatically and the pair of solar
arrays were not functioning correctly which later turned out that one had been pulled
off by the departing sunshade. NASA was now into a repair mission and had
to delay the next day crew launch whilst they figured if and how it was possible to fix
the problems and save Skylab. Over the next 10 day’s teams around the
US worked day and night to come up with a solution to fix the missing solar shield.
The idea was to make a parasol that would be attached to the side of the workshop and
then open it up to provide the shade required. As this was being done the backup crew practised
the operations in the Skylab underwater simulator to both fit the parasol and fix the solar
array. 10 days later the crew mission of Skylab 2
lifted off to try and rescue the $2.5 billion program, if they couldn’t fix the problems
that could spell the end of Skylab. Nothing like this had been done before, on
the Apollo 13 mission the crew had managed to jerry-rig CO2 scrubbers together with what
they had around the command module. On the Skylab mission, they would be working in space
and although they had an idea what was wrong they wouldn’t know exactly until they got
there. Once the crew arrived and on a televised fly
around they confirmed that the solar shield was gone as well as one of the solar arrays
and that the other was jammed by a strap that was part of now missing solar shield.
The crew managed to fix the parasol in place and release the stuck solar array, bringing
down the temperature in the workshop to acceptable levels and providing enough power for the
mission to continue. NASA learned that it was possible to work
in space and fix problems that relied upon the crews initiative, something that would
prove invaluable in the future for not only the assembling the ISS but for fixing the
Hubble Space Telescope, another multi-billion dollar program that had to be fixed in space.
Once Skylab was functioning it could carry on work but it was hardly what you called
luxurious. It was basically a giant tin can in which the crew would, eat, sleep and work,
with one window, onboard excrement store, and somewhat bland food.
This large open space allowed them to do things that are not possible now on the ISS such
as running around the wall and doing acrobatics. One of the things they discovered was that
if someone was spun around in a chair they would not get dizzy like they would doing
the same on earth, this showed that the inner ear relied on gravity to work.
Hundreds of experiments were carried out over the three missions on everything from exercise
in space to earth resources looking down at the earth to material sciences like welding
in space and growing crystals. Each of the three crewed mission stretched
the limit of human spaceflight endurance with skylab 2 lasting 28 days, skylab 3 56 days
and skylab 4 for 84 days. For the first time, we had a place to conduct
experiments into all aspects of living in space for longer periods of time. Not only
into how it affects the human body but how we could work in microgravity and how it affects
materials and processing of things that would be needed like growing plants for food.
There were also student requested experiments like bringing spiders on board to see if they
could build their webs in zero gravity. In fact it only took them a day or so go from
making a chaotic mess of a web to making one that looked pretty much like they did on earth.
One astronaut commented that they adapted to zero-gravity a lot quicker than humans
and without the months of training. Skylab had enough oxygen, food and water to
last 24 man-months though in the end they only used 16 months of the supplies.
Before departing for the last time, the Skylab 4 crew left food and provisions for the next
crew, which never happened, and left the hatch unlocked. They also used Apollo Command and
service module to boost the orbit by 11km and leaving it in a parking orbit.
It was known that without a further booster operation skylab would eventually fall back
to earth but this was not expected to occur until about 1983 and the Space shuttle was
due to come into service in 1979 to boost skylabs orbit.
To do this the Teleoperator Retrieval System or TRS was ordered by NASA in 1977 for use
in late 1979. This was a remotely controlled space tug that was designed to move payloads
around in space and boost or de-orbit spacecraft or satellites.
The idea was that Skylab could be saved and be used as the core of a new larger space
station. But despite having the worlds best sun observatory
on Skylab, NASA ignored warnings in 1973 by the British mathematician Desmond King-Hele
of the Royal Aircraft Establishment (RAE) that it would return in 1979 and again by
NORAD in 1977 who also revised their date to mid-1979 due to the effect of the largest
increase in solar activity in a century. Basically, with more energy coming from the
sun, the more earth’s upper atmosphere heated up and this expanded outwards causing slightly
more drag on Skylab. This would cause it to slow down, only very slightly but enough lower
its orbit more quickly than expected and instead of deorbiting in 1983 it was now going to
be some time in 1979. Problems with the space shuttle meant that
it was going to be delayed and would not be available to take the TRS to boost Skylab’s
orbit so the TRS was cancelled. The TRS could have been launched on a Titan or Atlas Agena
and controlled from the earth but the idea was also dropped as budgets were cut and Skylab
was left to a fiery fate a few years later. The debacle that was Skylab returning to earth
also showed that NASA needed to learn lessons on how to predict and handle the return of
a large piece of what was now space debris. There was a plan to have fuel onboard Skylab
to allow it to have a more controlled re-entry but that was later dropped because of the
fear that it could be a danger to the crews onboard, this left NASA with less control
where it would eventually end up on the earth. This caused a media frenzy as people who were
under Skylabs flight path were concerned that it could fall on them.
A few hours before the event NASA adjusted skylabs orientation to take it on a path that
would fly across the US and drop into the southern Atlantic about 1300 km south-southeast
of Cape town, South Africa to avoid flying over the more densely populated areas of Europe
and on to China. However, due to a 4% margin of error in the
calculations and that the main parts of Skylab took much longer to burnup than expected,
it carried along its flight path and over the southern Indian ocean where parts of it
fell but some continued onwards to southwestern Australia where they fell over an area stretching
from the town of Esperance on the coast to Rawlinna some 300km in a north-easterly direction.
Many pieces were found by local people with some saying that NASA had planned it to land
there rather than in the US because it was sparsely populated but in reality, you can
see that it was just at the end of its flight path and that if it had been controlled more
accurately with onboard fuel it could have been dropped in the ocean much more accurately.
Although it was fraught with problems, NASA was able to make good on what could have been
an expensive and humiliating failure and apply what it learned to future missions.
If Skylab had been lost just after its launch it would have set us back years and even with
the Space Shuttles Extended Duration Orbiter program which was never fully utilised for
month-long durations, it still wouldn’t have compared to the 510 man-days which were
spent on Skylab. The knowledge gained through NASA was open
to everyone in the world and soon the Soviets would use it to help build a succession of
new Salyut and Mir space stations culminating in the Zvezda which became the core of the
Russian part of the ISS. # This along with the modules from the US, Europe
and Japan forms the basis of what we know about individuals continuously living in space
for almost 2.5 years which will be invaluable for travelling to Mars in the not too distant
future and which is why it could be said that Skylab is probably the most influential space
program so far.
It was plagued with problems from the start but it turned out to be one of the most important
influential space programs we have ever done. Skylab unintentionally showed us that we could
fix major unexpected problems working in space and that we could survive in space for a long
periods of time and paved the way for the ISS. This is the story of Skylab, the first
and so far only US space station.
NASA learned many things from Skylab, one of them was the feasibility of doing an EVA
to fix mission level failures. Before they launched they had a list of situations that
they thought were no go’s and one of them was doing an EVA down the side of the module
to fix something like a solar array. But the problem they saw at mission control
was that the array was working but just not deploying.
They thought it might be able possible to fix the issue with some specially adapted
tools, so they took a calculated risk and with those tools, it was possible to do the
EVA and release the stuck solar array. This process of fixing a problem that you
might think isn’t be possible is the same as when you're learning a new skill and the
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