The Moon and its secrets
Twin Nasa spacecraft are set to blast into lunar orbit this weekend on a mission to study the subterranean structure of the Moon, to better understand the origins of planets.
The first Gravity Recovery and Interior Laboratory will begin orbiting the Moon at 21:21 GMT tonight, followed by GRAIL-B tomorrow at around 22:05 GMT, Nasa said in a statement.
“This mission will rewrite the textbooks on the evolution of the Moon,” said GRAIL head researcher Maria Zuber, of the Massachusetts Institute of Technology, adding that the spacecraft were so far performing well.
The $500 million pair of washing machine-sized satellites were launched on September 10 on a mission to map the Moon’s inner core for the first time.
Beginning in March 2012, the two unmanned spacecraft will send radio signals that allow Earth-based scientists to create a high-resolution map of the Moon’s gravitational field, helping them to better understand its sub-surface features and the origins of other bodies in the solar system.
The mission should shed light on the unexplored far side of the moon and test a hypothesis that there was once a second moon that fused with ours.
The two spacecraft have taken three months to reach the Moon as opposed to the usual three-day journey taken by the manned Apollo missions. The longer journey allowed scientists to better test the two probes.
The two spacecraft have covered more than four million kilometres since they were launched in September, according to Nasa.
As of Wednesday, GRAIL-A was 106,000 kilometres from the moon and closing in at a speed of 1,200 kilometres per hour. GRAIL-B was 128,000 kilometres away at a speed of 1,228 kph.
Scientists believe that the Moon was formed when a planet-sized object crashed into the earth, throwing off aload of material that eventually became our planet’s airless, desolate satellite.
How it heated up over time, creating a magma ocean that later crystalised, remains a mystery, despite 109 past missions to study the Moon since 1959 and the fact that 12 humans have walked on its surface.