Mars is red, Earth is blue. Here's a space laser story for you

NASA has decided to use fragments of Martian meteorites for target practice ahead of the Mars 2020 mission, then send one back to Mars.

The instrument doing the shooting is called SHERLOC - short for "Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals" - an instrument scheduled for the Mars 2020 mission.

As is the case with everything we send to Mars, SHERLOC will be calibrated, tested, then re-tested and re-calibrated before it makes the journey. And because SHERLOC's job is to apply its laser to whatever it sees on Mars, in order to understand its composition, NASA boffins decided that the best way to set it up was to let it shoot actual Martian rocks.

At this point some readers may remember that from time to time earthbound boffins have identified meteors on Earth's surface as having Martian offerings. Just last year we found half a dozen such interplanetary oddities.

All told we've identified about 200 such finds and SHERLOC gets to zap one of them, a rock called "SaU008" found in Oman in 1999.

London's Natural History Museum will lend the rock to NASA for SHERLOC's tests. It will also surrender some of the slab so it can travel with Mars 2020 so that once it arrives SHERLOC has a reference with which to work.

Mars 2020 will also carry candidate materials for future spacesuit fabric, gloves and a helmet's visor, so that SHERLOC can evaluate how they perform during its Martian sojourn. ®