Goutam Chattopadhyay Talks about Space Exploration and Terahertz Technology


Goutam Chattopadhyay (Photo: Bhagyashree Puranik)

Goutam Chattopadhyay is a senior research scientist at the Jet Propulsion Laboratory (JPL), California Institute of Technology (Caltech) and also a visiting Professor at the Division of Physics, Mathematics, and Astronomy at Caltech. After his undergraduate studies from the University of Calcutta (Bengal Engineering College), he worked at the Tata Institute of Fundamental Research (TIFR) as a Design Engineer. He built a local oscillator system for Giant Metrewave Radio Telescope (GMRT), working with Govind Swarup, one of the pioneers of radio astronomy in India. Chattopadhyay later earned his PhD from Caltech and joined JPL, a field centre of NASA associated with Caltech. His research interests include high frequency radars, terahertz instruments, and application of nanotechnology at terahertz frequencies.


Could you tell us about the history of JPL and NASA, and what they primarily do?

NASA started from JPL and not the other way round. JPL completed 80 years of existence in 2016 and NASA completed 50 years in 2008. A few professors at Caltech were conducting aerospace and propulsion experiments. They later started doing rocket launch experiments that eventually led Caltech to develop its own lab called the Jet Propulsion Laboratory. In 1958, when NASA was formed, since JPL was already experimenting on rockets, they brought JPL under the same umbrella. JPL is a unique place as it is a NASA lab, managed by Caltech and funded both by NASA and other external agencies. Being one of the largest labs of NASA, JPL currently has over 5000 employees, and primarily works on robotic missions (non-human missions). NASA, along with robotic missions, works on manned missions as well to which JPL provides technology.


How did you end up at JPL?

When I finished my graduate studies at Caltech, I was contacted by JPL as they were looking for someone with my background. I visited their lab before accepting their offer. In the USA, if you have a Masters or Doctoral degree, job interviews are very different. In India, candidates are usually asked to solve questions which test your technical knowledge. In the US, you visit people, they ask you to give a talk, so that they know about your work. Then you meet different people and interact with them. They then assess your public skills, because eventually you have to work in a group. This is what happened to me and then I landed up at JPL!


You develop instruments that work at terahertz frequencies. Could you explain terahertz technology and associated challenges?

Terahertz frequency is like any other frequency. Maxwell’s equations are frequency independent. However, the technology that we have to use to make instruments at different frequencies is different and this poses different challenges. If you look at the terahertz frequencies, the wavelength is such that the size of the component is of the order of wavelength, unlike that of microwave or optic components. At terahertz frequencies, components behave like an antenna and they radiate. You cannot use all the techniques applied at microwave frequencies. It is difficult to measure current at terahertz frequencies because of reflections and that is where the challenges are. If you want to make terahertz components, you have to use techniques from both microwave and optics. Until about two years ago, there were no amplifiers available to amplify signal at 1 terahertz frequency. So we have to develop new software along with hardware because the components behave differently. JPL builds software too.

It is difficult to measure current at terahertz frequencies because of reflections and that is where the challenges are.

Many people are familiar with projects like the Mars Rover/Curiosity. Could you briefly shed light on some other projects that NASA and JPL are involved in?

NASA and JPL do lots of different things. The three main areas of research are planetary sciences, astrophysics and Earth observation. Projects like Mars Rover mission and Voyager come under planetary sciences. Launched in 1970s, the Voyager has gone beyond our solar system and is still sending data back! Missions to comets and asteroids also come under this. Astrophysics deals with formation of stars and galaxies. It helps us understand how the Earth was formed. The Herschel Space Observatory, which was built by European Space Agency, has instruments contributed by NASA and JPL was involved in the design and development of some parts of those instruments. On the other hand, Earth observation deals with ocean studies, rain pattern, climate change and such things.


People often talk about the role of science in technology. Do you have any views on the relationship between the two since you were trained as both an engineer and a scientist?

Basic science drives technology. NASA is mandated to do science by trying to answer fundamental questions, such as the origin of life. And for this we need technology. For instance, to understand how stars are formed, we need to know what kind of measurements are to be made, what experiments are to be done and what kind of instruments are needed. To build that instrument, we must figure out what technology and components are needed. This is how science is connected to technology. New technology like the smartphone has a direct impact on science. A smartphone is a very powerful computer and it does a lot of things. Could we use this technology to do science? Could we have sensors built in our cell phones and perform measurements? We could have sensors attached to everybody’s smartphones and that would be a great thing, because, then, the technology in the hands of general public would be contributing to science.


How do you think an institute like IISc, that does both science and technology, can contribute to space technology?
IISc is a great place because it does research in both fundamental sciences and engineering. Even in space research, IISc can contribute significantly as space missions require people like mechanical engineers, thermal engineers, electronics engineers, communication engineers and computer scientists, from diverse backgrounds. All of this expertise can be found at IISc.


What is your advice to students who aspire to do research?

Very simple: be a good human being. Second, you must understand what you are studying. Some people study for marks. I don’t blame the students because that is how the system is. Selection of a Masters or PhD student in India is driven by marks. I tell students that even if you don’t get great marks, in the long run, you will be successful if you have basic understanding of the subject. In contrast, one good thing about USA’s higher education is that it picks students based not just on marks, but there are also many other things that they look for. Third, there is no substitute for hard work. If I have an option of taking a student for PhD, I would choose a hard worker over a smart candidate without a work ethic. If you are smart and not working hard, you are not achieving your potential. A hard working person will go much further. This being said, I believe at the end of the day, the most important thing in life is to be a good human being.

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