Prospero was the first and only satellite launched by the UK. It was fourth time lucky: three launch attempts had failed and the British government was threatening to cancel the project in favour of spending the money on Concorde. The program’s team decided that they had nothing to lose in going ahead with a fourth attempt. Thankfully, the launch went without a hitch and, on October 28th 1971, Prospero was put into Earth orbit.
The satellite had a number of functions, including using detectors to measure space dust in the Earth’s upper atmosphere. However, some of the instrumentation it carried had a limited battery life and stopped working in 1973. Nevertheless, the satellite continued to send signals back to Earth and was contacted officially every year until 1996. After that, amateur satellite trackers continued to detect the signal until it was last heard in 2004.
In 2011, on the launch’s 30th anniversary, a team from University College London attempted to regain communication. However, much of the technology had become obsolete and they didn’t have the necessary codes. They were eventually discovered typed on a piece of paper in the National Archives at Kew, London. However, by then, the anniversary had passed, as had enthusiasm for the project.
Despite the lack of contact, Prospero is still up there travelling at 17,000 miles per hour and orbiting the Earth every one hundred minutes. Its batteries are now completely flat and it is relying on 1970s solar panel technology. It will fall back to earth in around 100 years
A satellite has no conscience.
Earth’s orbit is becoming dangerously cluttered with debris. NASA estimates that there are around 500,000 objects bigger than a marble and 22,000 larger than a softball up there. Objects that size may not sound overly dangerous but even a fleck of paint, if travelling at 27,000kph as it would be in orbit, could easily penetrate a spacesuit.
In 2007, the Chinese tested an anti-satellite weapon by destroying their Fengyun-1C spacecraft. The explosion created over 2,000 pieces of junk bigger than 10cm, and an estimated 35,000 pieces more than 1cm across. And, back in 1961 and 1963, the Massachusetts Institute of Technology fired a cloud of 480 million needles into orbit to see if they could be used like an artificial ionosphere off which to bounce radio waves. Many of them are still up there.
Swiss scientists plan to launch a shoebox-sized satellite in 2016 that has jellyfish-like tentacles to sweep up the junk. Meanwhile, the European Space Agency plans to launch ATVs (Automated Transfer Vehicles) in 2015 that are equipped with optical sensors that can detect orbiting trash, gather it, and return it to Earth.
The first person to come up with the idea of artificial satellites was probably Sir Isaac Newton. In 1728, he devised a thought experiment where a cannonball is fired off the top of a very tall mountain at varying speeds. He realised that, at a certain speed, the cannonball would go on circling the Earth.
In 2004, the cheapest ever satellite launch took place. Russian cosmonauts on a spacewalk simply threw an old spacesuit containing a ham radio into space. The suit went into orbit and could be tracked by enthusiasts on earth. ‘Tossing’ may one day be a common method of putting satellites in orbit.
A satellite will send ideas into space, and ideas last longer than men.
In January 1997 a woman in Oklahoma was hit by a falling satellite. She was not injured.