Making lemonade from lemons: Scientists are going to repurpose two GPS satellites — launched into wrong orbits and thus useless for GPS — to conduct a test of Einstein’s theory of general relativity.
The satellites, operated by the European Space Agency (ESA), were mislaunched last year by a Russian Soyuz rocket that put them into elliptical, rather than circular, orbits. This left them unfit for their intended use as part of a European global-navigation system called Galileo.
But the two crafts still have atomic clocks on board. According to general relativity, the clocks’ ‘ticking’ should slow down as the satellites move closer to Earth in their wonky orbits, because the heavy planet’s gravity bends the fabric of space-time. The clocks should then speed up as the crafts recede.
On 9 November, ESA announced that teams at Germany’s Center of Applied Space Technology and Microgravity (ZARM) in Bremen and the department of Time–Space Reference Systems at the Paris Observatory will now track this rise and fall. By comparing the speed of the clocks’ ticking with the crafts’ known altitudes — pinpointed within a few centimetres by monitoring stations on the ground, which bounce lasers off the satellites — the teams can test the accuracy of Einstein’s theory.
There actually is little uncertainty here. No one expects this experiment to disprove Einstein’s theory, but the failed spacecraft provide a great opportunity to measure things at an accuracy never previously attempted, which in turn will help improve future GPS design.
From the press release: From the moment he is handed a possibility of making the first alien contact, Saunders Maxwell decides he will do it, even if doing so takes him through hell and back.
Unfortunately, that is exactly where that journey takes him.
The vision that Zimmerman paints of vibrant human colonies on the Moon, Mars, the asteroids, and beyond, indomitably fighting the harsh lifeless environment of space to build new societies, captures perfectly the emerging space race we see today.
He also captures in Pioneer the heart of the human spirit, willing to push forward no matter the odds, no matter the cost. It is that spirit that will make the exploration of the heavens possible, forever, into the never-ending future.
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