PolySat is building a new satellite for NASA’s Jet Propulsion Laboratory to carry cameras into space — everybody smile. Cal Poly’s eighth CubeSat will test new onboard image processing software, former project manager Brian Tubb said.
NASA gets to test its software on an inexpensive satellite, and PolySat gets the opportunity to work with NASA’s new technology in the CP8. PolySat has created an entirely new avionics system, the brains of the operation, Tubb said.
“It’s paving the way for all of our future satellites,” Tubb said.
NASA eventually wants to use its processing system on bigger, more important satellites, but it gets to test with CP8 cheaply. A typical NASA mission may cost up to $100 million or more, but the CP8 costs closer to $1 million, said Steve Chien, project leader for JPL.
“One of the most interesting things is because this is a much cheaper satellite, we can try out things and take risks that we really wouldn’t do with a much more expensive satellite,” Chien said.
PolySat has built or is building 10 CubeSats, and four of them have reached space. CP8, named IPEX, which stands for Intelligent Payload Experiment, has been in production for the past two years. PolySat anticipates finishing within the next month, Tubb said.
The IPEX has five onboard cellphone cameras, three megapixels each, just enough to make sure JPL’s image processing software works. The cameras will take up to five images per second and the processor will downlink the images to PolySat, Tubb said.
In this case, CP8 will process images of Earth, not powerful enough to see people, but basic outlines such as cloud movement and continents, Tubb said.
IPEX will pave the way for NASA’s proposed Hyper Spectral Infrared Instrument mission. The HyspIRI would use infrared imaging software to capture images of natural disasters, changes in the world’s ecosystems, the likelihood of future volcanic eruptions and much more, Chien said.
“HyspIRI is one of the missions for which IPEX is very specifically enabling and demonstrating the technologies for, but there’s a dozen or more missions under study for which IPEX, assuming it’s a successful technology demonstration, is going to test how these people think about their missions,” Chien said.
Because IPEX is an inexpensive satellite, it can’t control where it’s pointing to take images. It will tumble slowly when it reaches orbit and eventually use passive magnetics, a bar magnet put into the satellite, to align itself with Earth’s magnetic field, Tubb said.
The IPEX will turn at one rotation per second and will always have at least one side facing Earth. That ensures a radio link, Tubb said.
When images are taken and processed, they will be transmitted to PolySat over radio. The processor will choose which pictures to send, based on what NASA wants. In this case, Earth, electrical engineering senior Nicholas Weiser said.
“Is this a picture worth sending down to Earth? And if so, then it will send it whenever we tell it to,” Weiser said.
In addition to the image processing software, IPEX will orbit using a new processor running on Atmel hardware. PolySat previously used several different processors for each subsystem on the satellite. Now the team has created one main processor running Linux, Craig Francis, the CP8 team leader, said.
“We’ve greatly reduced the size of our avionics and we’ve greatly increased the processing power,” Francis said.
PolySat has increased satellite efficiency through an improved communication system. On previous CubeSats, everything was done through an audio card that collected data with a microphone and then input into the computer. That took much more time to send back the information, Tubb said.
It would have been like having one person who speaks Spanish and one person who speaks English with a translator in between, causing communication to be indirect and slow. Now, there are two people who speak the same language and don’t need to repeat the information through a translator, Tubb said.
“The basic way to describe it is we got two people that speak the same language,” Tubb said. It can go like 10 times faster, 100 times faster.”
PolySat has several tests to run on IPEX before finishing production, Tubb said. The IPEX needs to be put through space-like environments to test solar cells that generate power and extra protection mechanisms in case something shuts off while in space, Tubb said. The team will put IPEX in a vacuum and thermally cycle it to ensure it can withstand extreme temperatures.
PolySat anticipates launching IPEX in October. It will launch from Vandenberg Air Force Base via an Atlas V rocket. The satellite will go into low Earth orbit, 111 miles above the Earth’s surface, NASA says.
PolySat estimates that the mission lifespan will be six months. IPEX will eventually burn up in the atmosphere more than 20 years later, Francis said.
The IPEX provides an excellent learning experience for the engineering students involved, Tubb said.
“That’s always one of the major purposes of our lab,” Tubb said. “And a lot of people think they do and they don’t, so it’s a learning experience.
“We’ve just taught a dozen-odd students how to design a satellite, how to be an actual engineer.”
Katie Tomayko contributed to this article.