Key Takeaways
- SunRISE deploys six CubeSats forming a virtual radio telescope 10 kilometres across in space
- The mission targets solar radio bursts linked to particle storms that threaten astronauts and satellites
- Launching in mid-2026, SunRISE has no precedent as a multi-CubeSat interferometric array in deep space
A New Kind of Space Telescope
SunRISE – Sun Radio Interferometer Space Experiment – uses an approach to astronomy that has been standard on the ground for decades but has never been attempted at this scale in space. Six shoebox-sized CubeSats will fly in a loose formation approximately 10 kilometres across, each carrying a radio antenna. By combining signals from all six spacecraft, scientists can synthesize a radio telescope with an effective aperture of 10 kilometres – far larger than anything a single small satellite could achieve.
The technique is called interferometry, and its ground-based version underpins observatories like the Very Large Array (VLA) in New Mexico and the Event Horizon Telescope, which produced the first image of a black hole’s shadow in 2019. Translating it to free-flying spacecraft in deep space requires extremely precise timing and position knowledge, and SunRISE will serve as a proof-of-concept for whether that translation is feasible with affordable CubeSat hardware.
NASA’s Jet Propulsion Laboratory (JPL) manages the mission with principal investigation led by Justin Kasper at the University of Michigan. The six spacecraft will orbit the Sun at roughly the same distance as Earth, positioned to observe the Sun in the 0.1 to 25 megahertz radio frequency range – frequencies that are completely blocked by Earth’s ionosphere and thus inaccessible to any ground-based telescope.
What Solar Radio Bursts Reveal
The Sun routinely produces bursts of radio emission at these low frequencies, associated with energetic events such as solar flares and coronal mass ejections (CMEs). These radio bursts carry information about the physical processes that accelerate electrons and protons to high energies in the solar corona and interplanetary medium.
Specifically, Type II solar radio bursts are generated by shock waves propagating outward from the Sun at hundreds to thousands of kilometres per second. Type III bursts trace beams of energetic electrons traveling outward along magnetic field lines. The frequency at which these bursts emit drifts over time as the source moves to regions of lower plasma density, and tracking that drift provides a direct map of the shock or electron beam’s trajectory through interplanetary space.
That trajectory information matters practically because the same energetic particles driving those radio signals are the ones that pose radiation risks to astronauts in deep space. Solar energetic particle (SEP) events can deliver radiation doses to unshielded humans in cislunar space or on a Mars transit that exceed permissible career limits, and the particles arrive at Earth within minutes to hours of their acceleration near the Sun. A predictive capability that could identify which CMEs produce dangerous SEP events – and which do not – before the particles arrive would have direct operational value for missions like Artemis and future Mars expeditions.
The problem is that current understanding of what makes a CME a particle accelerator is incomplete. Not all CMEs produce dangerous SEP events. The factors that distinguish a particle-producing CME from a non-threatening one include the shock strength, the magnetic field geometry of the interplanetary medium, and possibly characteristics of the CME source region on the Sun. SunRISE would image the radio signatures of these events with spatial resolution that has never been achieved before, allowing scientists to connect what the Sun does near its surface to what particles arrive at Earth.
The Rideshare Architecture and Deployment Plan
SunRISE will fly as a secondary payload on a commercial launch, most likely a SpaceX Falcon 9 rideshare mission or an equivalent. Once in orbit, the six CubeSats will be deployed sequentially. Their formation will then be established using onboard propulsion, with each spacecraft maintaining its position in the loose 10-kilometre array using cold gas or electric propulsion.
The array does not need to be rigid or precisely maintained to centimetre accuracy. Interferometry requires knowing the positions of the antennas relative to each other at the time of each observation, and SunRISE will track spacecraft positions using GPS and inter-spacecraft ranging to compute the necessary baselines. Because the spacecraft orbit the Sun slowly relative to the timescales of solar radio bursts, the array will appear effectively stationary during any individual observation.
One challenge is that the six spacecraft must all be operational simultaneously to maximize the interferometric aperture. Losing one spacecraft degrades the resolution but does not eliminate science return. The mission design accepts this graceful degradation rather than requiring 100% functionality.
Connection to Space Weather Forecasting
NASA’s heliophysics programme has invested heavily in the past decade in understanding the chain of cause and effect linking solar activity to geomagnetic storms at Earth. Missions including Parker Solar Probe – which has made unprecedented close passes of the Sun since its 2018 launch – and Solar Orbiter, the joint ESA-NASA mission currently in operation, are providing close-in measurements of the solar wind and corona.
SunRISE complements those missions by providing the global radio imaging context that neither Parker nor Solar Orbiter can supply from a single vantage point. A Parker Solar Probe measurement of an energetic particle event near the Sun, combined with a SunRISE image of the corresponding radio burst, provides a level of observational linkage that has not previously been possible.
The NOAA Space Weather Prediction Center issues space weather forecasts with a maximum reliable lead time of perhaps one to three hours for SEP events. Scientists believe that incorporating directional and morphological information from radio imaging could extend useful warning times. Whether SunRISE delivers data that actually improves operational forecast skill – rather than advancing scientific understanding without affecting forecasts – is a question that will only be answerable after the mission accumulates observations through multiple solar events.
CubeSat Technology as a Scientific Platform
SunRISE represents a bet on the scientific potential of CubeSat platforms beyond their traditional role as technology demonstrators and educational tools. The standardized 10 centimetre cube form factor, developed at California Polytechnic State University and Stanford University in 1999, has enabled a large community of universities and small companies to build and fly spacecraft at a fraction of traditional costs.
Most CubeSats to date have flown in low Earth orbit on a few-month mission timescales, constrained by atmospheric drag and limited power budgets. SunRISE’s CubeSats will operate in a heliocentric orbit at roughly 1 astronomical unit from the Sun, where solar power is abundant and orbital lifetimes are not limited by drag. The spacecraft will need to operate autonomously for extended periods given the communications latency with Earth, and they will need to coordinate their observations without continuous ground contact.
JPL’s heritage in deep space mission operations brings considerable expertise to bear on those challenges. The SunRISE mission concept was selected through NASA’s Explorers Programme, which has historically produced high-return science missions at lower cost than flagship programmes. The total mission budget has been reported at approximately $62.6 million, a very modest sum for a mission targeting ly novel science.
What Success Would Unlock
If SunRISE achieves its primary science objectives, it will demonstrate two things simultaneously: that multi-spacecraft radio interferometry from deep space is technically feasible with CubeSat hardware, and that low-frequency solar radio observations from space can produce spatially resolved images of SEP-producing events. Both results have implications well beyond this single mission.
A demonstrated technique for deep-space CubeSat interferometry could be applied to other frequency regimes and other astrophysical targets. Jupiter’s radio emissions, planetary magnetospheres, and even low-frequency pulsar signals could all be accessible through an extended version of the same architecture. The cost model enabled by CubeSats could make large synthetic apertures affordable for investigations that would otherwise require a multi-billion-dollar single spacecraft.
On the space weather side, a mission that demonstrates the ability to image the directional properties of CME-driven radio bursts could justify a future operational monitoring system with similar capabilities – a space weather observatory rather than a science experiment. The path from SunRISE’s proof-of-concept observations to an operational system is not short, but without a proof of concept, that path does not exist at all.
Summary
SunRISE launches at a moment when space weather has moved from an academic curiosity to an operational concern with direct relevance to human spaceflight beyond low Earth orbit. The six CubeSats forming its distributed array cannot by themselves resolve the forecasting challenge, but they can generate the kind of spatially resolved solar radio observations that current instruments – ground-blocked and single-pointed – cannot. The mission’s modest price tag and innovative formation-flying architecture make it an unusually efficient way to test a ly novel capability. What happens next depends on what the Sun does during the mission’s operational window.
Appendix: Top 10 Questions Answered in This Article
What is the SunRISE mission?
SunRISE stands for Sun Radio Interferometer Space Experiment. It is a NASA mission consisting of six CubeSats that fly in a loose formation about 10 kilometres across, synthesizing a radio telescope to image low-frequency radio bursts from the Sun.
Why must SunRISE observe in space rather than from the ground?
Earth’s ionosphere completely blocks radio waves below approximately 30 megahertz, making ground-based observation impossible in the frequency range most relevant to solar radio bursts. SunRISE operates above this ionospheric cutoff in heliocentric orbit.
What is the scientific purpose of SunRISE?
SunRISE will image solar radio bursts associated with coronal mass ejections and energetic particle events, helping scientists understand which CMEs accelerate dangerous radiation storms and why. This has direct applications to protecting astronauts in deep space.
What are Type II and Type III solar radio bursts?
Type II bursts are produced by shock waves traveling outward from the Sun, while Type III bursts trace beams of energetic electrons moving along magnetic field lines. Both types drift in frequency over time as their sources move to lower-density regions of interplanetary space.
How large is SunRISE’s effective telescope aperture?
By combining signals from six CubeSats separated by up to 10 kilometres, SunRISE synthesizes a radio telescope with an effective aperture of 10 kilometres, using the technique of aperture synthesis interferometry.
What is the total cost of the SunRISE mission?
The SunRISE mission budget has been reported at approximately $62.6 million, placing it within the NASA Explorers Programme cost category for efficient, focused science missions.
When is SunRISE expected to launch?
SunRISE is expected to launch in mid-2026 as a secondary payload on a rideshare mission.
How are the SunRISE CubeSats powered in deep space?
The six CubeSats operate at approximately 1 astronomical unit from the Sun, where solar power is abundant. This heliocentric orbit avoids the power constraints that limit CubeSats in low Earth orbit where eclipse periods are frequent.
Who manages the SunRISE mission?
SunRISE is managed by NASA’s Jet Propulsion Laboratory, with principal investigation led by Justin Kasper at the University of Michigan. It was selected through NASA’s Explorers Programme.
What future missions could build on SunRISE’s technology?
A successful SunRISE mission could validate deep-space CubeSat interferometry for other targets including Jupiter’s radio emissions, pulsar observations, and planetary magnetospheres. On the applications side, the techniques could inform the design of a future operational space weather monitoring system using similar multi-spacecraft radio imaging.
