Physicists have waited 100 years to test the last unproven prediction of Albert Einstein鈥檚 theory of general relativity. Now they must wait another day at least.
The LISA Pathfinder mission, developed by the European Space Agency (ESA), is set to test the technology for building a gravitational wave observatory in space, which would be able to spot the ripples in space-time created by cosmic collisions 鈥� predicted by Einstein, but never seen.
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The probe was due to lift off from Kourou, French Guiana, at 04:15 GMT on 2 December, but with 12 hours on the countdown clock, mission control decided to hold off while they investigated a 鈥渢hermal issue鈥� with the Vega launcher.
鈥淭he behaviour of the engine under special circumstances raises questions,鈥� said Gaele Winters, ESA鈥檚 Director of Launchers, at a press briefing.
Specialists on site and in Europe are working on additional analysis to determine whether the launch can go ahead, he added. A decision is expected by 15:00 GMT today about whether to proceed on 3 December.
Mission scientists who travelled to French Guiana for the launch are disappointed, but sanguine. 鈥淓veryone鈥檚 so excited, and then it really is a downer to suddenly realise that we鈥檙e not launching today,鈥� says ESA project scientist Paul McNamara. 鈥淏ut at the same time, would I want to have LISA Pathfinder in a rocket which may work, may not work? No. We have waited 100 years for the anniversary of Einstein鈥檚 equations. What鈥檚 one more day?鈥�
The LISA Pathfinder spacecraft itself is in a healthy condition, McNamara says. Its fate is in the hands of launch service company Arianespace and the Vega rocket manufacturer Avio. 鈥淭hey鈥檙e very, very competent at what they do. They鈥檙e not going to take a risk with our satellite,鈥� he says.
Alvaro Gimenez, ESA Director of Science and Robotic Exploration, is confident that the launch will go ahead on 3 December. 鈥淚t鈥檚 a matter of double-checking things,鈥� he says. 鈥淣othing that requires real hardware or changes in the launcher. So I鈥檓 very optimistic it will work tomorrow.鈥�
Image credits, from top: ESA鈥揗anuel Pedoussaut, 2015; Sam Wong
