Old Spaceships Never Die..
15 January, 2008
In 1959 the Soviets launched a probe into space with the destination of the Moon. It was the first space craft to ever reach escape velocity from the Earth. Alas, due to a control system error the probe missed the moon and sailed out into stellar space. The Russians renamed the probe ‘Mechta’ – ‘the dream’ – it had become the first artificial satellite around the Sun. Orbiting between the Earth and Mars it is still out there, and has swung around the Sun nearly forty times since those first days when it missed its target. Hanging around in orbit is just one of the fates that awaits the robotic instruments we send out into space.
Landers have an easy time of it for the most part. Having landed (successfully or not) on a planetary body they tend to just sit there. Even remote rovers will eventually run down and come to a stand still. The Mars Rovers have been going well, but it’s only a matter of time before the ever present Martian dust clogs up their solar panels and leaves them powered down, quietly sitting on a lonely planet.
In the 1990s the Galileo mission went to Jupiter. Following on from the Voyager and Pioneer missions, this time the spacecraft did more than fly by at breakneck speed. It started by launching a small separate entry probe into Jupiter itself and sending back the data it received to Earth. For the next few years it orbited Jupiter taking measurements and amazing photos of the giant planet and its array of satellites. Of particular interest to scientists was Europa which may contain liquid oceans underneath its icy surface. In order to protect the Jovian Moons from accidental contamination by any bacteria, or other life that the spacecraft may have brought with it from Earth, a violent death was planned for the spacecraft. In 2003, it’s primary science mission finished, the probe was sent plunging into the atmosphere of Jupiter itself, following in the footsteps of the small probe it had sent into Jupiter eight years before.
Trapped in orbit around the sun, left to rot on a far off world, or plunged into a fiery death, none of them particularly appealing. For the Pioneer and Voyager spacecraft another fate lies in store. Hurtling along at immense speeds, these spacecraft are heading out of the solar system. It’s taken a long time, but Voyager 1, the fastest of all these probes, is now over 100 times as far from the Sun as the Earth is. It takes about 14 hours for the signals to get back to the Earth from this far off probe. Already it has passed some of the boundaries of the solar system – it is further away then the recently discovered Sedna for instance. It has passed the termination shock and is coasting through the heliosheath and will at some point head into interstellar space. Because of this more dignified way of finishing their missions, the Voyager spacecraft were fitted with golden discs containing sound and visual information about Earth. The discs were intended as part message, and part time capsule. Although the possibility is extremely remote an alien civilisation could find these probes, but perhaps it will be humans of the future who finally manage to catch up with these distant emissaries of Earth.