NASA scientists decode the reason for lunar orbiter's 'wild and jittery' 2014 images!

Image courtesy: NASA's Goddard Space Flight Center/Arizona State University

New Delhi: Every time an unmanned spacecraft or space vehicle launched for a probe for a limited time combusts in space to mark its end, the debris in space increases.

Currently, there are numerous satellites, unmanned space probes and missions and most importantly, the International Space Station (ISS) pacing the skies and one of their biggest tasks is to avoid meteors and other space rocks.

Curious space enthusiasts have often wondered how these space vehicles manage to evade these zooming space rocks and the answer is that space agencies keep very close track of the spacecraft's position and velocity, and given those, they can predict very precisely where it is going, so running into large objects is not a problem.

However, NASA's Lunar Reconnaissance Orbiter (LRO) was not so lucky when it had a collision with a tiny meteoroid in 2014, with its camera taking a hit.

Scientists have finally figured out the reason for the LRO camera's sudden strange photography on October 13, 2014 – quite the swerve from its previously clear images of the lunar surface – after it delivered an image that was wild and jittery.

From the sudden and jagged pattern apparent in the image, the LROC team determined that the camera must have been hit by a tiny meteoroid, NASA said in a statement on Friday.

"Since the impact presented no technical problems for the health and safety of the instrument, 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," said John Keller, LRO project scientist from NASA's Goddard Space Flight Centre in Greenbelt, Maryland.

"The meteoroid was traveling much faster than a speeding bullet," said Mark Robinson, Professor and Principal investigator of LROC at Arizona State University's School of Earth and Space Exploration.

"In this case, LROC did not dodge a speeding bullet, but rather survived a speeding bullet!" Robinson said.

LROC is a system of three cameras mounted on the LRO spacecraft. Two Narrow Angle Cameras (NACs) capture high resolution black and white images.

The third Wide Angle Camera captures moderate resolution images using filters to provide information about the properties and colour of the lunar surface.

During LROC's development, a detailed computer model was made to insure the NAC would not fail during the severe vibrations caused by the launch of the spacecraft.

The computer model was tested before launch by attaching the NAC to a vibration table that simulated launch. The camera passed the test with flying colours, proving its stability.

Using this detailed computer model, the LROC team ran simulations to see if they could reproduce the distortions seen on the October 13 image and determine the size of the meteoroid that hit the camera.

They estimate the impacting meteoroid would have been about half the size of a pinhead (0.8 millimetre), assuming a velocity of about seven kilometres) per second and a density of an ordinary chondrite meteorite (2.7 grams/cm3).

"LROC was struck and survived to keep exploring the Moon," Robinson said.

Launched on June 18, 2009, LRO has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the Moon.

(With IANS inputs)