The proverbial scientist’s work in being a part of designing and developing the Perseverance is now on course to define the Mars exploration.
She is the proverbial rocket scientist. Swati Mohan, the Mars 2020 Guidance, Navigation, and Controls Operations Lead at Jet Propulsion Laboratory in Cape Canaveral is relieved. The team completed the successful launch of the Mars 2020 Perseverance on July 30, 2020 at NASA, and also finished its first manoeuvre in outer space on August 14. Swati’s work in being a part of designing and developing the landing tech, the Terrain Relative Navigation System for Perseverance is now on course to define Mars exploration, with four more manoeuvres and many turns scheduled before its much-anticipated February 18, 2021 landing on the Red Planet.
Mohan who is at the crux of Perseverance, the centerpiece of NASA’s $2.7 billion Mars 2020 mission designed this “seeing and listening” rover. About her role, Swati Mohan says, “The GN&C subsystem is the ‘eyes and ears’ of the spacecraft. During the cruise phase, our job is to figure out how we are oriented, ensure the spacecraft is pointed correctly in space (solar arrays to sun, antenna to Earth), and manoeuvre the spacecraft to get it where we want to go. During EDL, GN&C determines the position of the spacecraft and commands manoeuvres to help it land safely. As operations lead, I am the primary point of communication between the GN&C subsystem and the rest of the project, responsible for training the GN&C team, scheduling mission control staffing, as well as policies and procedures in the mission control room.”
Perseverance seeks to find signs of ancient Mars life inside the 28-mile-wide (45 km) Jezero Crater, which once hosted a lake and river delta.
Swatiis entrenched deep into manoeuvreing the trajectory. The Bengaluru-born girl who migrated with her parents to the US when she was just a year old, has been at the heart of the mission, in design and development of rover that is more advanced than Curiosity. Its new Terrain Relative Navigation System allows it to be the first rover to land with open eyes. “Previous missions have relied on radar to land. Radar can tell you how far above the ground you are, so it allows a safe landing. It is similar to holding out your hands and stopping when your hands touch something. By using a camera, Terrain Relative Navigation allows Perseverance to ‘see’ where it is, so it can not only land safely, but also at a specifically selected place. It allows the rover to land with its eyes open. During descent, while on parachute, Perseverance will take pictures of the ground and compare these images to a map of Mars. By identifying features in common between the images and the map, it can determine where it is on Mars, thus it finds the safest spot it can reach by looking it up in a pre-generated ‘Safe Targets Map,’ and aims for that spot,” she explains.
For a girl who wanted to be a pediatrician growing up, space has been her clarion call. Ever since physics ignited a fire, this MIT and Cornell alumni was hooked. “I wanted to be a pediatrician until I was 16-years-old. I was always interested in space, but I didn’t know about opportunities to turn this interest into a career. At 16, I took my first physics class. I was lucky enough to have a great teacher, and everything was so understandable and easy. That was when I considered engineering, to pursue space,” Swati recalls.
Innumerable calculations connecting with millisecond precision seamlessly, Swati has a single-minded focus on the course now. Yet, there were some nerves too. “Before the launch, I was nervous, but felt prepared. By the time of launch, we had gone through three full rehearsals, including one where we practiced for multiple complications. For the launch itself, most of the work is done by the launch vehicle team, so our job at JPL mission control only starts once we get a signal from the spacecraft after launch. Once we got data, I could verify that GN&C hardware was working correctly, and the spacecraft was safe and healthy, that was a big relief,” says the space scientist.
The Mars robotic rover landing is termed as ‘Seven Minutes of Terror.’ The JPL engineer explains, “Entry, descent, and landing is often referred to as ‘seven minutes of terror’ as it takes seven minutes to get from the top of the Martian atmosphere to the ground. During this time, there are so many changes and commands that need to occur in exact sequence, with millisecond precision. Any one action that doesn’t happen correctly can potentially lead to Perseverance crashing on the surface, and the loss of the whole mission. The time is takes for light/information to travel from Mars to Earth on the day of landing is about 11 minutes. So, the operations team on Earth cannot do anything to help or fix issues, because by the time they receive information of something going wrong, Perseverance would have crashed on the ground (or not) already.”
Given the extremely exacting and irrevocable nature of the mission, with seven months from touch down, work is on rigorously. “Right now, the operations team is flying the spacecraft to Mars. During the seven-month cruise to Mars, we have about five course-correction manoeuvres to complete to aim towards Mars, and a handful of turns in order to keep the vehicle oriented with its solar arrays to the sun and antenna pointed at Earth. We perform regular checkouts of all hardware to ensure everything is healthy and ready for landing day,” explains Mohan, who did her PhD at Massachusetts Institute of Technology in aerospace, aeronautical and astronautical engineering, and then was a PhD student at MIT Space Systems Laboratory.
Interestingly, the maps – the onboard the TRN system will compare its imagery to precisely aligned maps quite like GPS, only these will map the Mars surface. “The comparison of the imagery to onboard maps is like looking for street signs, then finding those streets on your maps. Once you know where you are, you can decide where to go and how to get there,” she adds.
The beginnings
Swati joined the Mars 2020 Perseverance mission in 2013 when her supervisors apprised her of an opportunity. “I joined with the intent of learning as much as possible by seeing this mission through all development and operational phases,” she recalls.
Complicated formulas and equations are the holy grail of every space exploration. Landing on the Jezero Crater to find ancient, microbiotic life, is undoubtedly immeasurable in its learning curve for Swati. “The biggest lesson I learned was that simple is best. Complexity makes comprehension hard, and opens the door for issues to hide in the cracks of what can’t be understood. We strove to have clean understandable interfaces, so that we could break up the large complex problem into smaller manageable ones,” she adds.
As the Mars rover cruises, is seven months a long wait? Swati clarifies, “Mars 2020 has one of the shortest cruise times to Mars. As a result, we have to squeeze in all the different calibrations and checkouts into a shorter time period. It’s still fairly busy, so I have been keeping my head down and focusing on the next major thing at a time.”
When not keeping an eagle eye on Perseverance, or deep in calibrations, she is also the manager of Jet Propulsion Laboratory’s Small Satellite Dynamics Testbed. “My colleague and I founded the lab about seven years ago to support the development and testing of CubeSat, and small satellites at JPL. We have even designed our own Star Field Simulator to provide a realistic space environment for star trackers. Most of the JPL missions use our facility to do functional and phasing testing of the GN&C hardware prior to integration into the CubeSat.”
Being at the crux of space exploration is an exciting and invigorating endeavour, one that Swati has grasped with immense passion and dedication, yet she is grounded even in the heights of space exploration.
Before the Mars 2020 Mission, Mohan worked on Cassini, the mission to Saturn and GRAIL, the mission to the Moon. “Cassini was exciting as it was a flagship mission to Saturn. I got to work on it during the year when Cassini reached Saturn, and released the Huygens probe. There were exciting new images coming down every day. The GRAIL mission was exciting as it was the first pair spacecraft to be flown in formation around a planetary body that is not Earth. It was challenging and fun to move both spacecrafts in perfect unison to get to the lunar orbit that the science needed,” says Mohan.
The Indian and Bengaluru connection
With a strong connection with Bengaluru, Swati has been coming to India at least every three to five years. “I was born in Bangalore, but moved to the United States when I was a year old. My parents still have a house in Bangalore, and spend a part of every year there,” reveals Swati.
And that is not all, as like any big Indian family, hers is close knit. “I do have a lot of extended family (cousins, aunts and uncles) still in Bangalore, and other parts of India,” adds this mother of two daughters.
Married, Swati’s husband Santhosh is a pediatric infectious disease doctor and a microbiologist, and his family is also from Bengaluru.
For any space aficionado, the contemplation of unearthing a new planet and finding signs of microbial life is exhilarating indeed. For Swati too, this particular thought has captivated her since childhood. In fact, one William Shatner aka James T Kirk of Star Trek absorbed that little girl’s mind! “I remember watching my first episode of Star Trek at the age of nine, and seeing the beautiful depictions of the new regions of the universe that they were exploring. I remember thinking, ‘I want to do that. I want to find new and beautiful places in the universe. The vastness of space holds so much knowledge that we have only begun to learn.” And Perseverance, it seems will get her there.