Teams of astronauts spent more than 171 days in Earth orbit aboard Skylab, the first US space station. Launched in 1973, the Skylab mission proved that humans could spend extended periods in space and improved our understanding of the Sun.
Although the mission initially suffered from a launch-damaged thermal shield, more than 120,000 detailed photographs of the Sun were taken by the three crews that visited the station before it re-entered the Earth's atmosphere and broke apart in 1979.
Photo: Scientist-astronaut Edward Gibson outside the Skylab space station (NASA)
Crews on the first US space station study the Sun.
The first solar space laboratory in orbit loses its heat shield.
Shortly after launch in 1973, Skylab, the first solar space laboratory, lost its heat shield. Astronauts who visited the orbiting science station had to rig a temporary protective barrier to bring temperatures inside Skylab down to safe levels.
Astronauts see solar flares and coronal mass ejections in great detail.
Following in the steps of Sun observers such as Galileo and Angelo Secchi, US astronauts aboard the Skylab space station captured more than 160,000 images of the Sun. They saw events such as solar flares and coronal mass ejections in great detail. Skylab was launched in 1973.
Skylab was the United States' first space station, orbiting Earth from 1973 to 1979, when it fell back to Earth amid huge worldwide media attention. Launched and operated by NASA, Skylab included a workshop, a solar observatory, and other systems necessary for crew survival and scientific experiments. It was launched unmanned by a modified Saturn V rocket, with a weight of 170,000 pounds (77,111 kg). Lifting Skylab into low earth orbit was the final mission and launch of a Saturn V rocket (which was famous for carrying the manned Moon landing missions).
To transport astronauts to Skylab, there were a total of three manned expeditions to the station, conducted between May 1973 and February 1974. Each of these missions delivered a three-astronaut crew, carried in the Apollo Command/Service Module (Apollo CSM) launched atop the Saturn IB rocket, which is much smaller than the Saturn V. For the final two manned missions to Skylab, a backup Apollo CSM/Saturn IB was assembled and made ready in case an in-orbit rescue mission was needed, but this backup vehicle was never flown.
The station was damaged during launch when the micrometeoroid shield separated from the workshop and tore away, taking one of the main solar panel arrays with it and jamming the other main solar panel array so that it could not deploy. This deprived Skylab of most of its electrical power, and also removed protection from intense solar heating, threatening to make it unusable. However, the first crew was able to save Skylab by deploying a replacement heat shade and freeing the jammed solar panels, which was the first time a major repair was performed in space.
Skylab included the Apollo Telescope Mount (a multi-spectral solar observatory), Multiple Docking Adapter (with two docking ports), Airlock Module with extravehicular activity (EVA) hatches, and the Orbital Workshop (the main habitable space inside Skylab). Electrical power came from solar arrays, as well as fuel cells in the docked Apollo CSM. The rear of the station included a large waste tank, propellant tanks for maneuvering jets, and a heat radiator.
Numerous scientific experiments were conducted aboard Skylab during its operational life, and crews were able to confirm the existence of coronal holes in the Sun. The Earth Resources Experiment Package (EREP) was used to view Earth with sensors that recorded data in the visible, infrared, and microwave spectral regions. Thousands of photographs of Earth were taken, and the record for human time spent in orbit was extended beyond the 23 days set by the Soyuz 11 crew aboard Salyut 1, to as much as 84 days by the Skylab 4 crew. Plans were made to refurbish and reuse Skylab by using the Space Shuttle to boost its orbit and repair it. However, due to delays with the development of the Space Shuttle, Skylab's decaying orbit could not be stopped.
In the hours before re-entry, NASA ground controllers attempted to adjust Skylab's trajectory and orientation to try to minimize the risk of debris landing in populated areas. NASA's attempted target was a spot 810 miles (1,300 km) south-southeast of Cape Town, South Africa. Skylab's atmospheric reentry began on July 11, 1979, and people on earth and an airline pilot saw dozens of colorful firework-like flares as large pieces of the space station broke up in the atmosphere. Skylab did not burn up as fast as NASA expected, and Skylab debris landed southeast of Perth in Western Australia, resulting in a debris path between Esperance and Rawlinna. Over a single property in Esperance, 24 pieces of Skylab were found. Analysis of some debris indicated that the Skylab station had disintegrated 10 miles above the Earth, much lower than expected.
After Skylab, NASA space station/laboratory projects included Spacelab, Shuttle-Mir, and Space Station Freedom (which was later merged into the International Space Station).