NASA’s Moon orbiting spacecraft Lunar Reconnaissance Orbiter Camera (LROC) was a hit by a small meteoroid faster than the speed of a bullet but the camera survived though it is unclear whether the mission will face any other eventuality.
From October 13, 2014, the US space agency’s Lunar Reconnaissance Orbiter spacecraft suddenly started sending jarred pictures indicating that it could have been hit by a tiny meteoroid in space. LROC has three cameras, two of them Narrow Angle Cameras (NACs) to capture high resolution black and white images.
Mark Robinson, principal investigator of LROC at Arizona State University (ASU) in the US, said the jittery images could be the result of a sudden and extreme cross-track oscillation of the camera, which promted LROC researchers to conclude that there was a hit.If there had been any other damage to the orbiter, then both cameras would have been malfunctioning, which is not the case, explained, Robinson.
Most of each NAC is sequestered inside the spacecraft structure, so only the leading edge of the baffle and the radiator are exposed to space, and thus are potential targets for impactors. When the team ran simulations to determine the size of the meteoroid that hit the camera and calculated the impacting meteoroid to have been about half the size of a pinhead (0.8 millimetre) but a velocity of about seven km per second.
“The meteoroid was travelling much faster than a speeding bullet. In this case, LROC did not dodge a speeding bullet, but rather survived a speeding bullet!” said Robinson.
Ever since it was launched on June 18, 2009, LRO has been sending beautiful and clearer pictures of Moon’s surface and data. It captures images during daylight. “It is somewhat amazing that this event was captured in a NAC image. LROC typically images only during daylight, and then only 10% of the day. So to begin with there was only a 5% chance of an impact occurring during image acquisition. I wonder how many times LROC and LRO have been hit by other meteoroids? Maybe there is another NAC image recording a similar event and we have not found it yet?,” said Robinson.
Announcing the damage after almost seven months, John Keller, LRO project scientist from NASA’s Goddard Space Flight Center, said:”The team is only now announcing this event as a fascinating example of how engineering data can be used, in ways not previously anticipated, to understand what is happing to the spacecraft over 380,000 kilometres from the Earth.”