On their last workshop at Monrovia, NASA shortlisted three landing sites among eight pre-determined zones for their 2020 Mars rover mission.This three landing site includes Northeast Syrtis, Jezero Crater, Columbia Hills. Those three sites were chosen for three different reasons. NASA’s Spirit lander already explored Columbia Hills in earlier 2000s and Northeast Syrtis was once used to be the site of volcanic activities.

Most of the scientists are pinpointing to the Jezero Crater because it is the remnants of a Martian lake. So, chances of getting the sign of life are much higher at Jezero Crater. Although, scientists are less enthusiastic about Columbia Hills because it’s already been drilled out by Spirit rover in 2000.

Arizona State University’s planetary Scientist Dr. Steve Ruff said in a statement,“I wouldn’t be pushing it if I didn’t think there was a case to be made [Columbia Hills]. The bottom line comes down to what we observed with Spirit, which is so compelling”. According to Gizmodo, Spirit found opaline silica deposits within the Columbia hills. Those deposits are usually made from amorphous opal mineral.

Opaline Silica could be easily found on Earth near the hot springs and active volcanic areas. Ruff believes that opaline silica formed Mars in the same way.hot spring fluids are used to be mineral riches that could sustain microbial communities. As per Scientific American, microbial life can affect the shape of the rock. Back in February 2007, Spirit rover drove through the Gusev Crater in search of an ancient lake.

Instead of finding a lake, Spirit unexpectedly found opaline silica. This mineral usually accumulates by the activity of hot springs. As everyone knows that hot springs are habitable on Earth and the deposits can preserve Microbes. So there are tons of possibilities for getting fossilized Martian microbes in the opaline silica deposit of Columbia Hills. However, some scientists feel that revisiting and scooping up on the Spirit’s old stomping grounds would be expensive and rare.