The Sun Radio Interferometer Space Experiment, or SunRISE, will launch later this year and is designed to work as a single, distributed radio telescope in orbit high above Earth. Once deployed, the six spacecraft will operate in formation to track powerful radio bursts generated deep within the sun’s outer atmosphere, known as the corona.
Those radio bursts are associated with solar energetic particle events, which in extreme cases can pose a serious risk to astronauts and satellites by exposing them to intense radiation. By detecting and tracking the radio signals produced by these events, scientists hope SunRISE will improve forecasts of dangerous space weather and help limit its impacts.
Before being cleared for launch, the toaster-oven-sized satellites were put through a comprehensive testing campaign at Utah State University’s Space Dynamics Laboratory in Logan, where they were designed and built. The testing regime was intended to ensure the spacecraft could survive both the violence of launch and the unforgiving environment of space during their planned one-year prime mission.
The program included thermal vacuum testing to simulate the extreme temperatures and vacuum conditions the satellites will encounter in orbit. Engineers also carried out electromagnetic compatibility tests to confirm the spacecraft’s electronics would not interfere with the sensitive scientific instruments on board.
The final stage involved vibration testing, which subjected each satellite to intense shaking designed to mimic the stresses experienced during launch.
“Each spacecraft was fuelled to match its launch mass and then vibrated along all three axes,” said Jim Lux, SunRISE project manager at NASA’s Jet Propulsion Laboratory in California. “The goal was to replicate launch conditions as closely as possible. We ran full functional checks before and after the tests, and all six spacecraft passed without issue.”
The heliophysics mission will lift off from Cape Canaveral Space Force Station in Florida as a ride-share payload aboard a United Launch Alliance Vulcan Centaur rocket. The launch is sponsored by the US Space Force’s Space Systems Command.
Following launch, the satellites will be deployed slightly above geosynchronous orbit, at an altitude of around 35,000 kilometres. Once in position, each spacecraft will extend four telescoping antenna booms, about 2.5 metres long, arranged in an X-shape.
Flying in formation up to 16 kilometres apart, the six satellites will collectively form a single, large radio telescope. After sending data back to Earth via NASA’s Deep Space Network, scientists will use a technique known as interferometry to combine the signals from each spacecraft into one coherent observation.
This approach will allow researchers to detect solar radio bursts and map the sun’s magnetic field from the outer corona into interplanetary space with unprecedented detail.
“Solar radio bursts occur when huge amounts of energy stored in the sun’s magnetic field suddenly accelerate particles to extremely high speeds,” said SunRISE principal investigator Sue Lepri from the University of Michigan. “By tracking these events, we can not only help protect astronauts and spacecraft, but also deepen our understanding of how space weather is generated and how it propagates through the solar system.”
NASA said SunRISE will complement several of its existing heliophysics missions, including the Solar TErrestrial RElations Observatory, the Parker Solar Probe, and the Solar Orbiter, a joint mission with the European Space Agency, adding a new perspective on the sun’s influence well beyond Earth.