No planet in the solar system has captured public imagination like the red planet, with more than 100,000 people signing up for a one-way trip to Mars when applications opened this year. Mars was the topic of the evening when Dr. Anita Sengupta delivered her speech at the Media Resource Centre in the Central Library at 5.30 pm on Tuesday, 20th of August.
A graduate from the University of Southern California, Viterbi School of Engineering, Dr. Sengupta is now Project Manager at the Jet Propulsion Laboratory, NASA. She was the lead systems engineer of ‘Curiosity’, a space rover designed to collect data from Mars. Dr. Anita is also an Adjunct Astronomical Engineering Professor at University of Southern California. A cheerful 35-year-old, she describes herself as “an avid science fiction fan who drives airplanes and rides motorcycles”.
Dr. Anita began her presentation with an introduction to the planet Mars. As the planet closest to the Earth, it has long been scrutinised by scientists for signs of life or at least an environment conducive to it. While frozen water had been found in the polar regions of the planet, it is believed that there is now less water than before. This is attributed to the evaporation and escape of water from the planet owing to its weak gravitational pull (about one third the Earth’s) and less dense atmosphere (about 1% of the Earth’s).
She went on to speak about the “Seven Minutes of Terror” between Curiosity’s entry into Mars’ atmosphere and its landing. Those seven minutes were everything her team had worked for – there were 500,000 lines of code involved, with zero margin for error. And zero error it was as Curiosity landed successfully on August 6th 2012.
They had chosen the Gale Crater on Mars, believed to have been a source of water, as the place of landing – a tough decision since it was surrounded by mountains, leaving the rover only a small area it could land on. The high degree of accuracy required made the team’s task that much more challenging.
Dr. Anita then elaborated on the different phases involved in the rover’s landing. It had to decelerate from 13,000 miles per hour to about 2 miles per hour in a very short time. This energy was dissipated over several stages – first, a large, specially designed parachute was deployed for a reduction of speed to the terminal value of 250 miles per hour. The rover then deployed Hydrazine-powered rockets, which generated an opposing thrust. Finally, a manoeuvre referred to as the ‘Sky Crane Manoeuvre’ was used to place the rover on its wheels on the planet’s surface. With seventeen cameras, a robotic arm to perform various functions and many more, Curiosity was primed to go.
Curiosity has now been on Mars for over a year and has moved only 1.6 kilometres, but has sent in huge amounts of valuable data that scientists are working on everyday – data, Dr. Sengupta explains, that will determine whether Mars could one day become a planet conducive to human inhabitation.
Among Curiosity’s many discoveries so far are evidence of water having flowed on Mars, pH neutral soil which can support life and the presence of phyllosilicates which form only in the presence of water. And the rover is far from finished with its mission.
Dr. Anita was also personally involved in the creation and design of the ‘Supersonic Parachute’, designed to bear 65,000 pounds of weight. She brought a smaller version of one along to show everyone, much to the delight of the audience. While developing this, her team had to simulate the atmosphere of Mars on Earth, for which they employed a ‘Supersonic Wind Tunnel’.
She concluded her lecture with an interactive session where students asked several questions, most of which were technical in nature. The evening came to a close with a thunderous round of applause from the audience.