A Martian meteorite uncovered on Earth 20 years ago is embarking on a historic return journey via NASA's Mars 2020 Perseverance mission. Scientists at NASA will use it to precisely calibrate key instruments.
The Natural History Museum in London has custodied this meteorite, named Sayh al Uhaymir 008 (SaU 008), since its discovery in Oman in 1999. Ejected from Mars around 650,000 years ago, a fragment recently arrived at NASA's Kennedy Space Center in Cape Canaveral, Florida, ahead of the highly anticipated Mars 2020 launch on July 30, 2020. Soon, it will return to its home planet.
“Each year, we provide hundreds of meteorite specimens to scientists worldwide for study,” explains Caroline Smith, head of Earth sciences collections at the museum. “But sending one of our samples back roughly 100 million km from home to advance our knowledge is a true first for us.”
NASA plans to use this sample to calibrate the SHERLOC instrument on Perseverance's robotic arm. Featuring a laser, a camera (WATSON), and spectrometers, SHERLOC will scan rocks for potential biosignatures.
Mars' harsh conditions—extreme temperature swings, pervasive dust, and relentless UV radiation—demand rigorous calibration. To ensure measurement accuracy, the rover's instruments require periodic recalibration using known standards.
That's why Perseverance carries a dozen calibration samples of various materials, including the Martian meteorite. Every three to five months, engineers will target these to confirm that on-site readings align with the samples' established properties.
For optimal calibration, the meteorite mirrors Martian surface rocks. Composed primarily of basalt—abundant on Mars—SaU 008 proved ideal. Moreover, its durability stands out. “Some Martian samples we hold are quite fragile,” Smith notes. “But this one is tough as nails.”
Perseverance is slated to touch down in February 2021 at Jezero Crater, a site potentially habitable billions of years ago. Select samples collected there will be cached for eventual return to Earth.
Back on Earth, advanced lab analysis will reveal Mars' secrets, much like Apollo lunar samples deepened our understanding of the Moon.
Source
