On Wednesday, at 12:10:27 GMT, ESA’s Planck space telescope ended its four and a half year mission when project scientist Jan Taube sent the command telling the unmanned probe to switch itself off. Called ESA’s “time machine,” the spacecraft was sent into solar orbit to prevent it from becoming a hazard to future space missions.
Launched on May 14, 2009 from the Guiana Space Centre in French Guiana along with ESA’s Herschel space telescope, Planck was sent to the Sun-Earth L2 point, where the gravitational forces of the Earth and Sun cancel one another out, allowing the craft to maintain it’s position. It was tasked with studying the Cosmic Microwave Background (CMB); the echo of the Big Bang that kicked off the physical universe.
Built by Thales Alenia Space, Planck’s cryogenically cooled instruments were more sensitive than any previously sent up to study the CMB and allowed the telescope to produce more detailed maps in the microwave and infrared spectra at higher resolution than was previously possible. Operating at a tenth of a degree above absolute zero, the telescope allowed scientists to look back to the beginnings of the Universe to about 380,000 years after the Big Bang.
Planck completed both its primary and secondary missions, which ended in January when it ran out of liquid helium to cool its main detector. But it continued on using its secondary instrument until the decision was taken to end the mission. In August, Planck was sent into solar orbit and instructed to fire its engine until all its fuel was expended. On Tuesday, the command was transmitted to deactivate it.
"Planck has provided us with more insight into the evolution of the Universe than any mission has before," says Alvaro Giménez, ESA’s Director of Science and Robotic Exploration. "Planck’s picture of the CMB is the most accurate 'baby photo' of the Universe yet, but the wealth of data still being scrutinized by our cosmologists will provide us with even more details."
The video below gives an overview of Planck’s mission.