Aditya Madanapalle

The first interplanetary mission by India was originally expected to be in orbit around Mars for only six months. The Isro scientists used their technical skills to indefinitely extend the Mars Orbiter Mission, and the spacecraft continues to take scientific observations. The Mars Orbiter Mission has discovered superhot argon in the upper atmosphere of the red planet, a finding that has implications on the energy deposition in the upper Martian atmosphere, and is an important step in explaining why the Martian atmosphere escape rate is higher than previously believed.

An experimental payload on board the Mars Orbiter Mission, known as the Mars Exospheric Neutral Composition Analyser (MENCA) made the discovery. The MENCA is one of the five scientific payloads on the orbiter. MENCA is a mass spectrometer, developed by the Space Physics Laboratory of the Vikram Sarabhai Space Centre in Thiruvananthapuram. The observations were made in 2014, when the orbiter was at its closest distance to the surface of the planet, known as the periapsis. The MENCA previously progressed scientific understanding by studying the unique characteristics of the upper Martian atmosphere during evening time.

The superhot argon in the upper atmosphere is not a persistent occurrence. Normally, the upper atmosphere on Mars has a temperature of -3.15 Celsius. In the obrits when superthermal neutral argon atoms are observed, the temperature spikes to 126.85 Celsius. The hot argon atoms are extremely energetic, and hence have high kinetic temperatures. The research has been published in the Geophysical Research Letters vol. 44, a journal of the American Geophysical Union (AGU).

Last month, Isro scientists executed a maneuver that saved the Mars Orbiter Mission from becoming dysfunctional. The problem was that Mars was eclipsing the sun for too long in a particular orbit, and spending so much time in the darkness meant that the orbiter's energy supplies would have been drained. There is 30 kg of fuel on board, and the instruments are in good health, which indicate that the first interplanetary mission by India will continue to observe the red planet for a "very long time". The data collected by the instruments on board is being shared with the scientific community worldwide.