Alumnus Update: Siddharth Krishnamoorthy
Siddharth Krishnamoorthy is a 2010 scholar who studied Aeronautics at Stanford University. He currently works at the NASA Jet Propulsion Laboratory in Pasadena.
This week he shares with us why the laboratory is developing technology for balloon-based exploration of Venus.
All views expressed here are his personal views. This article is written in a personal capacity, not as a representative of the NASA Jet Propulsion Laboratory, California Institute of Technology.
It has been a long journey spanning decades that has led to my current position working as a Research Technologist for the NASA Jet Propulsion Laboratory (JPL), but one filled with learning (ask my mother how long she had to say I was in “college”), and brightly accentuated by my exceptional mentors and peers. When I received the Inlaks award in 2010 to start my graduate education in aeronautics and astronautics at Stanford University, I had already been on this journey for a decade or so, and without the support of the foundation I could not have completed the second half, something I remain eternally grateful for. I completed my masters and PhD degrees at Stanford in 2017 and moved to Pasadena, California to work as a postdoctoral associate at JPL, eventually transitioning to my current position as a member of the research staff.
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As a Research Technologist, I am involved in a number of technology development projects focused both on Earth science and planetary exploration. My main focus at this time is technology development for balloon-based exploration of Venus. If flying balloons on Venus sounds like a crazy idea, you may be surprised to know that the Soviet Union already flew two of them back in 1985. This was during the golden era of Venus exploration during which humankind discovered that the planet that was an inhospitable hellscape. The surface of Venus is intensely hot at 460 degrees Celsius and the atmosphere is bone-crushingly dense at 90 bar atmospheric pressure (similar to 1 km deep in Earth’s oceans). When you escape the torrid conditions of the surface and float higher up, the temperature becomes more Earth-like about 50-60 km above the surface, but you find yourself surrounded by a cloudy haze of sulphuric acid and winds at almost 400 km/h that rotate around the planet faster than the planet rotates about its own axis. All this to say, Venus is a strange place, unexpectedly so. Indeed, before we sent spacecraft to Venus, the expectation was to find conditions similar to Earth – Venus is not that much closer to the Sun than Earth, and is strikingly similar in size and mass. The next question, of course, was “why”. Why did Venus get that way, despite its similarities to Earth? Was it doomed from the beginning, or did Earth and Venus evolve along the same path until some set of catastrophic events sent Venus spiraling down a different pathway? Unfortunately, before we could send more spacecraft to answer these very important questions, Mars occupied centerstage in planetary exploration and Venus remained largely ignored. Not anymore, however. In the last few weeks, space agencies around the world have resoundingly voted to go back to Venus, bag and baggage. First, NASA selected not one but two missions to Venus named VERITAS and DAVINCI+ in its Discovery competition. These missions will investigate the planet’s topography, chemical composition and its atmosphere. These comprise the first missions that NASA has sent to Venus in three decades. In addition, the European Space Agency (ESA) announced the selection of the EnVision mission to Venus. The Indian Space Research Organization (ISRO) also has plans to visit Venus with Shukrayaan-I within this decade.
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The interesting thing about space exploration is that the more you look, the more you learn, but also the more you realize you don’t know. Surely, this will be the case with Venus – the three new missions will answer some long-standing questions about our mysterious and underexplored neighbour, but also raise many more for future exploration of the planet from vantage points within its atmosphere and even on the surface.
One important science question for Venus is the study of its internal structure, an important piece in the effort to puzzle together why it diverged so dramatically from the Earth’s evolutionary path. Typically, this type of study utilizes seismometers deployed on the surface to measure ground motion from seismic activity such as quakes and volcanic eruptions. We know that the Earth has a layered interior with a crust, mantle, and core; we know this because of seismic networks around the world. With the surface of Venus being so inhospitable, the lifetime of instruments we send there is severely limited – no lander we have sent to the surface of Venus has survived for more than 3 hours. However, the balloons that the Soviet Union floated 54 km above the surface lasted for at least two days, after which contact was lost due to the loss of battery power. Modern balloons designed for Venus use are now projecting lifespans greater than 60 Earth days. If there was some way to perform seismology from balloons, this extended lifespan would allow for much longer seismic experiments and increase the chance of detecting ongoing activity and study the internal structure of Venus.
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My current research primarily focuses on developing such a balloon-based technique, which would measure minuscule atmospheric disturbances generated by seismic activity on the surface of Venus, known as infrasound, and study the internal structure of Venus while floating 50-60 km above its surface. Over the last few years, the team that I work with has developed instrument packages and floated them on balloons over devices that generate artificial seismic activity such as seismic “hammers” (exactly what the name suggests) and buried chemical explosions. In 2019, we flew balloons equipped with our instruments, tens of thousands of feet above a seismically active area in California. This brought us the most consequential result of our project so far, as we demonstrated the first detection of a natural earthquake from a high-altitude balloon at an altitude of nearly 16,000 feet above sea level. Being able to demonstrate this technique on Earth is an important stepping stone towards performing this task on Venus. Moving forward, we hope develop this technology for implementation in balloon-based missions that will hopefully be proposed in the future.
There is so much more exciting work beyond what I have mentioned here that I get to be involved in at JPL. My career is now primarily geared towards building things that fly to other planets. It is a deeply satisfying experience for me to work on challenging technological problems in space exploration. Part of the satisfaction is being able to do what I wanted to do as a kid – there are very few things that parallel this sort of joy. I often reflect on the arduous path that brought me these opportunities, and it fills me with gratitude for the Foundation, which was instrumental in helping me overcome the barriers I faced.
Cover Image: Siddharth Krishnamoorthy
Image 1, 2 and 3: Building, Inflating and launching solar-heated balloons during an experimental campaign in 2019 for detecting earthquakes from the air. (Image credit: NASA/JPL-Caltech)
