Sen—Today is the 35th anniversary of the day when one of the most important orbiting solar observatories fell from the sky. Launched by NASA, it was a spinout of the Apollo programme. The technology that took humans to the Moon in the 1960s brought the Sun into focus the following decade. This mission was called Skylab.
When the Apollo 11 mission landed two men on the Moon in 1969 it took only six days for NASA to announce their plans for to put a space station in orbit. They wanted to show that humans could survive in this newly conquered environment for weeks at a time. A modified Saturn V rocket would both launch the space station into orbit around the Earth and provide a home and workspace for its astronauts by repurposing its third stage. Skylab only needed to get into low earth orbit and reach an altitude of 435 km above the Earth, so the third stage of the Saturn V wasn’t needed for propulsion.
Skylab was just that—an orbiting science laboratory that allowed astronauts to do medical research, monitor the Earth and carry out astrophysical research, including solar. It carried the Apollo Telescope Mount that housed eight instruments that provided images and spectra of the Sun in visible, ultraviolet and X-ray wavelengths in a compartment about the same size as a transit van.
In total three crews each involving three astronauts visited Skylab and spent a total of 171 days, 13 hours and 14 minutes in orbit. Part of the astronauts’ pre-launch training had been in solar physics. They gathered images that showed the corona was shaped by magnetic fields and measured the chemical composition of the atmosphere.
The third and final crew left Skylab on 8th February 1974 and although plans were discussed that Skylab would operate for many years, and have its orbit boosted by a visit from the Shuttle that was then being developed by NASA, it only survived until 1979. Engineers at mission control made their preparations to monitor Skylab’s return home.
The space station began to lose altitude and slowly dropped as its orbit decayed. It finally fell to Earth on 11th July 1979. The re-entry was uncontrolled although NASA engineers could make changes to the orientation of Skylab to do their best to influence the timing and location of the landing. Speculation and media interest in the fate of Skylab, which had a mass of almost 80,000 kg, soared. With the world watching, Skylab eventually came in over the Indian Ocean and scattered itself over the southern part of Western Australia.
I made a pilgrimage to see what remains of Skylab in 2011. Many bits remained surprisingly intact. Including a large oxygen tank. If you want to see these for yourself you can follow my footsteps. I flew to Perth, Australia, and then drove for a couple of days to reach the town of Esperance where Skylab now lies. That’s one short holiday for me, but one giant chunk of Skylab for mankind.