Although Mars looks like a dry and dusty planet, science says that it used to be warm and wet along with an atmosphere. It was in this condition for billions of years, suitable for the development of life. However, we are not sure if life existed there or not.
Efforts to understand the ancient habitability of Mars has increased in recent years. MSL Curiosity is looking to find evidence of life which existed billions of years before around the Gale Crater, which is a dried-up lake bed and a prime spot to find evidence.
Christopher House, Geoscience Professor at Penn State University who is also a participating scientist with the Mars Science Laboratory of NASA said that Gale Crater appeared to have been a lake environment, as the mission found finely layered mudstones in the crater. It is estimated that water would have persisted for more than a million years. Gale Crater is a complex place. Besides being a lake bed, there are minerals which provide clues to habitability in Mars. However, it was finally filled with sediment, which turned to stone and then eroded. This same process also led to the creation of Mt. Sharp in the middle of Gale Crater. However, the entire system lasted more than a billion years. Sulfate has filled many fractures, indicating that water went through the rocks, even after no lakes were being formed in the planet.
House works with Sample Analysis at Mars (SAM) and stratigraphy, sedimentology teams of Mars Science Laboratory. SAM uses instrument to heat the rock samples and mass spectrometer for measuring the molecules released by heated samples which helps to identify the types of gases released.
Researchers are interested in the sulfur gases from sulfate and sulfide minerals as the presence of decreased sulfur minerals such as pyrite would mean that the environment might have supported life previously. This is partially due to the fact that formation of pyrite needs organic matter in the sediment. The sedimentology and stratigraphy team studies the rock layers on Mars for understanding the environment they were formed. House directs daily teleconference with the researchers few times every month for planning the operations of Curiosity on Mars for the next day.
He said that it is fun to be involved in its everyday operations for taking decisions such as where to take measurements, where to drive or which measurement to be prioritised over another one in a limited time. Each day’s time is limited by the power which the rover contains and how much it requires. He feels that it has been an important learning experience in how missions are operated and collaborate with researchers all over the world. The daily operations of Curiosity is very fast and detailed. This is a golden age of planetary science. Every new driving operation brings different fields of view with different rocks and new questions to ask.
It is similar to a new world every time it moves, but bringing into discussion the same questions about the events which occurred months before. However, it is necessary to deal with the new landscape and perform the operations for that day. Although we know a whole lot about Mars, it is still a dynamic and fascinating place. Similar missions have shown that it was a habitable environment in the past. Missions have also shown that there occurs methane releases in Mars and volcanic eruptions not so long ago. There is a lot of interest in Mars as it is quite similar to Earth than other planets in the solar system. Venus has fully different conditions, Jupiter is a planet filled with radioactive gases and the remaining planets are far away from Sun.
In 2014, Curiosity detected methane spikes associated with organic processes along with organic carbon compounds. The rover also found evidences of ancient stream bed on Mars in 2013 proving the presence of water in the past on Red Planet.
Initially, the mission length of MSL Curiosity was targeted at 687 days since its landing on August 2012. However it has been going on even after 2500 days. It will keep going on until its radioisotope thermoelectric generator loses its power.