New Solar Array Technology Could Revolutionize Space Exploration

When a recent SpaceX Dragon resupply capsule arrived at the International Space Station (ISS), among the 7,000 pounds of food supplies and equipment was a pair of ISS Roll Out Solar Array (IROSA) solar panels. 

 

Roll Out Solar Array. Image used courtesy of NASA 

 

These state-of-the-art panels are destined to join four other IROSA panels already installed on the ISS to replace the aging rigid solar panels supplying the energy operating the orbiting station.   

Development of the Roll Out Solar Array (ROSA) solar panels began in 2009 to replace traditional rigid solar arrays with a compact design that is more affordable and can be deployed on a variety of spacecraft, including those used in low-Earth orbit and others whose missions could include interplanetary travel. 

 

Solar Power in Space

The sun is the largest power source in space, producing more power per second than humanity has consumed in the past 70 years. Most spacecraft use solar panels to harness this energy, but traditional solar arrays are often expensive, heavy, and complex to operate.

The new ROSA technology is revolutionizing space exploration. ROSA arrays are compact and roll up like a carpet for launch, making them much easier to transport than traditional large, bulky solar arrays. Despite their compact size, ROSA panels are highly efficient and can produce more than 30 kilowatts per panel.

ROSA arrays use a unique deployment system that is simple and reliable. Unlike traditional solar arrays, which use motors and complex electrical systems, ROSA arrays use strain energy in composite booms to self-deploy. The strain energy is similar to stored energy in a spring and is used to deploy the panels into position, reducing the number of moving parts and making the ROSA more reliable and less likely to fail.

ROSA panels are designed to withstand the harsh space environment, including extreme temperatures, radiation, and micrometeoroid impacts. The arrays are also modular for easy repair or replacement.

 

Space Installations

In 2021, NASA astronauts installed two of the new IROSA panels on the ISS. To install the new arrays, they are rolled out in front of the old legacy solar panels. The IROSA can produce more than 28 kilowatts (kW) of power at the beginning of its life. Each IROSA is nearly half the size of the legacy arrays, allowing the unshaded portions of the original arrays to continue producing a combined power of about 95 kW. Since then, two more IROSAs were added, and with the two additional ones that were just delivered, once all the six IROSAs are installed, the station’s power generation may increase to a combined total of more than 250 kW, representing an increase of 30 percent over the previous solar power capability. This will sufficiently power the ISS until it is decommissioned in 2030.

ROSA was originally developed by Deployable Space Systems (DSS) with support from NASA Space Technology Directorate (STMD). Since 2009, STMD has funded parts of DSS’s journey, from conceptualizing ROSA to its development, culminating in successful technology demonstrations, operational mission use, and other cutting-edge potential applications. DSS was acquired by Redwire Space in 2021, continuing the use of ROSAs on NASA and commercial missions. 

In addition to their use on the ISS, ROSA panels are also used on the Double Asteroid Redirection Test (DART) mission. ROSA arrays have the potential to revolutionize space exploration by making it more affordable, efficient, and reliable. As ROSA arrays develop, they will become even more powerful and versatile. ROSA arrays could power everything from small satellites to large space stations in the future. They could even power missions to the moon, Mars, and beyond. Closer to home, the roll-out compact design might find a variety of applications for temporary emergency power systems or to provide off-the-grid power in remote and inaccessible locations.