A Satellite Mishap is Allowing Physicists to Test Einstein’s Theory of Relativity

Last year, a Russian Soyuz rocket accidentally placed two ESA-operated GPS satellites into elliptical, rather than circular, orbits. The faulty launch leaves the satellites unfit to perform their intended duties as part of a global Galileo GPS system, but a a new opportunity has arisen;
Physicists now have a unique opportunity to test one of the key predictions of Albert Einstein’s theory of general relativity: That clocks run more slowly when they’re close to heavy objects, because of how gravity warps the fabric of spacetime.
As the two Galileo satellites swing toward and away from the Earth in their oblong orbits, German and French physicists will track the speeding and slowing of time using the spacecrafts’ on-board atomic clocks.
To date, our best measurements of the so-called time dilation effect were made in 1976, in an experiment that lasted a mere two hours. The Galileo satellites will be tracked for a year, enabling physicists to make measurements up to four times more accurate.
By this time next year, we’ll have a better idea of exactly how much gravity causes time to dilate. The impromptu experiment is a great reminder of how failures can be turned into opportunities in science.