Established in 1958, the Department of Defense’s (DOD) Defense Advanced Research Projects Agency (DARPA) is the departmental organization tasked with promoting the creation of technologies that uphold and enhance the military’s capabilities and technological dominance. DARPA-funded research has achieved significant advances in science and technology that have influenced the creation of both military and commercial products, including stealth, the internet, personal electronics, and precision-guided missiles. The ideology of risk-taking and tolerance for failure at DARPA has encouraged specialists, some members of Congress, and others to see DARPA as a role model for innovation both outside and inside the federal government. For specialized missions, the DARPA agency hires different space businesses.
Executives from Millennium Space unveiled the findings of a 2-year experiment on July 20 involving three small satellites deployed from the ISS (International Space Station) in both 2019 and 2020.
Three 70-kilogram satellites built by Millennium Space, which is a Boeing company that makes small and medium satellites, were part of the so-called Red-Eye project, which was supported by the Defense Advanced Research Projects Agency. A DARPA contract obtained in 2016 was used by the business. In December 2021, the trial was over.
Jason Kim, CEO of Millennium, said during a discussion with reporters that the experiment showed that low-cost smallsats are now capable of achieving capabilities including on-board data processing, inter-satellite communications, and software-defined radios. Since none of the three satellites had internal propulsion, the experiment’s unanticipated finding was the ability to regulate the orbital separation of the system using strategies for managing atmospheric drag.
“We wanted to have a specified spacing of our satellites while designing our crosslink operations so that we could show crosslinks at different ranges. As a result, Doug Hulse, program manager of Red-Eye at Millennium Space, explained how his team came up with a way to regulate the constellation’s spacing solely through aerodynamic drag on its solar arrays.
A very limited amount of atmosphere exists in low Earth orbit (LEO), he said. The air drag, which ordinarily would force a satellite to slowly deorbit, was instead exploited to impact the distance between the satellites. The constellation was then given the ability to virtually self-control its orbital spacing using ground-based automation techniques, which was a step further by engineers.
This was an important lesson learned from the experiment since satellite propulsion isn’t always a possibility, according to Hulse. The satellites were not permitted to have onboard propulsion due to the fact that they were launched from the ISS for safety concerns. Hulse praised drag modulation as fantastic innovation. “When we began the program, that wasn’t initially planned.”