In an extremely unlikely sequence of events a camera on a NASA craft fitted with three cameras was hit by a meteoroid while compiling an image, researchers have determined. The Lunar Reconnaissance Orbiter called the LRO was hit in 2014.

The researchers noticed that something was wrong when the craft that takes photos of the surface of the moon sent a strange image back to Earth. The craft is in orbit, so it takes photos one line at a time to adjust for movement, and then uses thousands of line images to compile one full image.

The odd photo the LRO sent back to Earth after it was hit by a meteoroid. Photo: NASA

The images are usually extremely detailed and of a high quality so when researchers got the above unusual image  they began to work figuring out what went wrong. The disruption in the image can been seen in the slight waves in the photo that are more severe in the center of the photo.

The researchers determined that the camera used to take the photo must have been hit by something directly, likely a meteoroid, while it was taking the photo. Researchers tested the cameras under conditions of turbulence to ensure that take off and launch wouldn't have any ill effects on them. Using the same simulations they had used to test the cameras before take-off, they tested it under various conditions to try to replicate the photo they had received from space, according to NASA.

Bullet hole - a small stone from the universe went through our solar array. Glad it missed the hull. pic.twitter.com/iBHFVfp1p8

— Chris Hadfield (@Cmdr_Hadfield) April 29, 2013

What is a meteoroid?

A meteoroid is pretty much any chunk of rock or iron that travels through space. They're smaller than asteroids and usually are small pieces that have broken off of the larger masses. They can also sometimes break off of moons. When a meteoroid enters Earth's atmosphere and burns up it's then called a meteor or a shooting star. Usually they burn up in the atmosphere but in the event they don't, and they end up landing on Earth, then they're called meteorites.

This helped them determine the size of the meteoroid that hit as well. Eventually concluding that it was likely the size of about half a pin head and traveling faster than a bullet does.

This event is so rare because the craft only takes photos during times when it's bright and even then it only spends about ten percent of that time actually capturing images, according to Mark Robinson a principal investigator on the craft.

The LRO is still in space orbiting and collecting information because the event didn't cause any threatening damage to the craft or hinder its function further then the one time photo disturbance.

"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," said John Keller, an LRO project scientist, according to NASA.

In 2013, an astronaut on the International Space Station tweeted a photo from the station of a small hole in one of the station's solar panels. The "bullet hole" as the Canadian astronaut Chris Hadfield called it was caused by a small meteor.

The ISS can navigate out of the way of large asteroids if necessary but it's expected that it will be hit with small pieces of space debris every few months, a NASA spokesperson told Space.com. NASA scientists also spend time tracking larger pieces of debris so the ISS can prepare or move in plenty of time if necessary.