This month, NASA announced that a small satellite to be designed and built by Brown students has a ticket to ride on a future rocket launch. The news arrived just a few months after a prior Brown student-built satellite ended a successful mission of more than two and a half years in space.
The new satellite, dubbed PVDX, is a cubesat — a class of miniature satellites ideal for doing low-cost science experiments or technology demonstration in space. Members of Brown Space Engineering (BSE), a student group, worked for three years to develop a mission plan and proposal for NASA’s Cubesat Launch Initiative, which uses auxiliary cargo space on rockets to send cubesats to space. Sarang Mani, a Brown senior and the group’s project manager and co-president, says the team is thrilled that NASA saw value in their project.
“It’s a huge validation of all the time and effort that everyone on the team has invested into this,” Mani said. “I think it speaks volumes to the amazing pool of young people who are excited about space and are working to make it more accessible.”
The primary mission of PVDX, which stands for Perovskite Visuals and Degradation eXperiment, will be to test the performance of next-generation perovskite solar cells in the harsh orbital environment. Perovskites are emerging as a low-cost challenger to silicon for making highly efficient solar cells. A research team led by Brown professor Nitin Padture has made key contributions to the development of perovskites, and the BSE team will work with Padture’s group to develop perovskite cells for PVDX. The team aims to find out how this type of solar cell, which has never flown in space, performs in an environment where temperatures can swing by as much a 500 degrees Fahrenheit.
“We’re planning on flying 30 perovskite cells of varying compositions and comparing them to gallium arsenide cells, which are pretty standard in aerospace applications,” said Lauren Adachi, technical lead and co-president of BSE. “We’ll be flying both kinds of cells so we’ll be able to do a side-by-side comparison of how they perform.”
PVDX’s secondary mission is to engage K-12 students in space exploration. The plan is to allow students to send short messages to the satellite, which will be displayed on an LED screen on one side of the spacecraft. A camera attached to a small robotic arm on PVDX will snap a picture of the display — with an orbital view of the Earth providing the backdrop — and transmit that picture back to the students from space. The idea, the team says, is to help create excitement about space exploration, and to show students that getting there isn’t as difficult as they may think.
“We want to show that even as students, they can make cool things and send them to space,” Mani said. “The accessibility of space is a big part of what our group is about.”
Adachi says that ethos of accessibility and inclusion extends to how BSE goes about its work internally. “Inside of BSE, this means making space engineering accessible regardless of prior experience and making sure people from all backgrounds feel like they are able to contribute to our projects,” she said.
PVDX will be substantially more complex than BSE’s last satellite, called EQUiSat. For starters, PVDX is larger. EQUiSat was a 10-centimeter cube, whereas PVDX is more like a small shoebox — 30 centimeters long and 10 centimeters in its other dimensions. The size difference alone makes PVDX’s avionics more complicated, Adachi says. Communications will be more complex as well. While EQUiSat transmitted data related to its position and system function, PVDX will need to receive more complex instructions from the ground and return larger datasets including image data to ground stations on Earth. That requires a beefed-up radio system, more powerful antennas and an upgraded power system.
Daunting as those challenges may be, the team isn’t starting from scratch. Mani and Adachi say the team will build on the lessons learned in building that first satellite. Work on EQUiSat started in 2013, and the project was handed down through several cohorts of students before it was completed and launched in 2018. Mani says that many BSE alumni who worked on the original project make themselves available to provide help and support.
“We have a lot of people who were deeply involved with the team and who continue to be active on our communication channels and are accessible whenever we need advice,” Mani said. “That’s actually more important than all the technical information that we have stowed away. You can stare at a schematic all day trying to figure out what’s going on, but it takes 10 minutes for someone who has experience to talk you through it. That’s a huge help.”
Mani, who graduates on May 2, is about to become one of those valuable resources for current and future students. He was present when EQUiSat launched from Wallops Island, Virginia, in 2018 and he hopes to reunite with the team for PVDX’s launch, which is slated for a window between 2022 and 2025.
“One of the transformational parts of my time at Brown was going to that launch and meeting the founders of the team,” Mani said. “I fully expect that I’ll be back to see the PVDX launch and get to meet all of the new students who worked on it.”
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