NASA’s toaster-oven-size SunRISE satellites won’t launch before mid-2027

Six spacecraft the size of toaster ovens are waiting for a ride to orbit that will not come before the middle of next year. NASA announced on October 6, 2026 that its SunRISE mission, short for Sun Radio Interferometer Space Experiment, will launch no earlier than mid-2027 on a SpaceX Falcon Heavy rocket from Kennedy Space Center in Florida. The satellites will fly as a rideshare payload rather than on a rocket of their own, with the payload sponsored by the United States Space Force’s Space Systems Command.

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In January, NASA was still planning a launch later in 2026 on a different rocket, a United Launch Alliance Vulcan Centaur from Cape Canaveral. The newest announcement gives a launch window and no explanation for the timing, so the reason behind the slip is unstated. What the agency does spell out is what the satellites are for: watching the Sun’s outer atmosphere for radio bursts that come before hazardous particle storms.

Six SmallSats acting as one radio telescope

According to NASA’s Jet Propulsion Laboratory, SunRISE consists of six small satellites, each about the size of a toaster oven, that “will operate as one giant radio dish.” The spacecraft will sit slightly above geosynchronous orbit, at an altitude of about 22,000 miles, or 35,000 kilometers. Spread out in formation, the six work as a single instrument far larger than any one of them, which is the idea behind radio interferometry.

The January mission update described how that formation is meant to look. Each spacecraft deploys four telescoping booms about 2.5 meters long, arranged in an X, and the six fly up to 16 kilometers apart. They send their data through NASA’s Deep Space Network, and scientists combine the observations on the ground into one large radio telescope. Each spacecraft has a one-year prime mission, according to the post on the SmallSats passing their tests.

Radio bursts as a window on solar storms

The science target is the Sun’s corona. NASA says the mission will track radio bursts from the corona and study energetic particle events that “may pose a hazard to satellites and astronauts.” The logic, laid out in the SunRISE post announcing the new date, is about timing: the radio waves reach Earth before the solar energetic particles they accompany, so following the bursts could improve prediction and mitigation of the particle storms that follow.

Sue Lepri, the mission’s principal investigator at the University of Michigan, has described the physics behind the signal: solar radio bursts are triggered after vast quantities of energy stored in the Sun’s magnetic field are released. A formation of antennas tuned to those low-frequency emissions gives scientists a way to map that field from the outer corona out into interplanetary space, according to NASA’s January description of the mission goals.

NASA’s SunRISE mission page lists the expected duration as 12 months and a launch of “Mid-2027,” and frames the objective as examining how the Sun releases particles into space. The January description names three complementary missions that look at the same problem from other angles: STEREO, the Parker Solar Probe and the Solar Orbiter, which is run by ESA and NASA. SunRISE adds a radio view from high above Earth, where the whole formation can watch the corona at once.

Hardware that has already passed its tests

The satellites are finished, which makes the wait unusual. At Utah State University’s Space Dynamics Laboratory in Logan, they went through thermal vacuum testing to simulate orbit and electromagnetic compatibility testing to confirm the electronics would not interfere with the science instruments. They were also shaken on all three axes to simulate launch. Jim Lux, SunRISE project manager at JPL, said each spacecraft was loaded with propellant to match launch mass for the vibration tests, and that all six aced the pre- and post-test functional checks.

NASA’s July 13 post on the switch to Falcon Heavy says the SmallSats completed assembly and testing and will be stored at the laboratory until the launch period is confirmed. The launch is a rideshare sponsored by the United States Space Force’s Space Systems Command, and SunRISE is a Mission of Opportunity in the Explorers Program managed by NASA’s Goddard Space Flight Center. The University of Michigan in Ann Arbor leads the science investigation, while JPL, a division of Caltech, manages the project.

For now the key date is the one NASA gave: no earlier than mid-2027. Because that wording is a floor and not a promise, the launch could still move, and the agency has not said when it will name a firmer date. Until then the six SmallSats stay in storage at the Space Dynamics Laboratory, where they were built and tested, and the earlier plan for a launch later in 2026 on a Vulcan Centaur no longer applies. NASA has not said how the change of rocket and the later date are related.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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