A British-built probe that will help to open a new window on the universe has blasted off from Europe’s spaceport in Kourou, French Guiana.
Lisa Pathfinder will test ultra-sensitive technology for observing gravitational waves – ripples in the fabric of spacetime predicted a century ago in Albert Einstein’s General Theory of Relativity. The fluctuations are thought to be generated by accelerating massive objects. They are so tiny that the ripples emitted by a pair of orbiting black holes would stretch a million kilometre-long ruler by less than the width of an atom. Scientists hope to find evidence of gravitational waves using detectors both on the ground and in space.
A Vega rocket carried the Lisa Pathfinder spacecraft into orbit just after 4am after the launch had earlier been postponed. Within the probe are a pair of identical 46mm gold-platinum cubes separated by 38 centimetres which will be isolated from any kind of internal or external force except gravity. The mission involves monitoring the relative position of the cubes to an astonishing degree of precision.
Lisa Pathfinder was built for the European Space Agency (Esa) by Airbus Defence and Space in Stevenage. Scientists from the universities of Birmingham and Glasgow, and Imperial College London, contributed elements of its test package payload. Dr Chris Castelli, director of programmes at the UK Space Agency, said: “Lisa Pathfinder is one of the most unique European space missions to date, requiring engineering that has never been done before. “We’re immensely proud that this challenging mission to discover the unseen part of our universe was built here in the UK.”
A laser will be used to look for deviations as small as a few picometres – less than the diameter of an atom – in the position of the free-falling cubes. Scaled up, this is the equivalent of tracking the distance between the tops of the London Shard and New York’s One World Trade Center, and spotting changes down to fractions of the thickness of a human hair. Gravitational waves could provide valuable information about some of the most cataclysmic events in the universe.
The spacecraft itself will be an active part of the experiment, firing tiny thrusters about 10 times a second to adjust its position and avoid making contact with the floating cubes Alvaro Gimenez Canete, Esa’s director of science and robotic exploration said: “Gravitational waves are the next frontier for astronomers. We have been looking at the universe in visible light for millennia and across the whole electromagnetic spectrum in just the past century. But by testing the predictions made by Einstein one hundred years ago with Lisa Pathfinder, we are paving the road towards a fundamentally new window on the universe.”