June 30th, 2023
Redwire Corporation announced it was awarded a contract from Boeing to develop two additional solar arrays for the International Space Station.
Over the last two years, the ISS has received six Roll-Out Solar Arrays (iROSAs), all built by Redwire under contract from Boeing, to augment the aging station’s existing power-generating capability. It’s now set to get two more as early as 2025, according to NASA.
“The six iROSAs installed on the ISS are innovative examples to support further utilization with technologies and systems that were not envisioned when the ISS was designed and built,” said John Mulholland, Boeing’s vice president and program manager for the ISS, in a June 28, 2023, statement. “It is a tribute to the performance of the design, build, and operational teams that NASA has contracted for two additional arrays to complete the upgrade to the full eight-array set.”
Delivered in pairs on three SpaceX cargo Dragon missions in June 2021, November 2022 and most recently in June 2023, each was installed over six of the eight existing legacy arrays.
The legacy arrays are 112 feet long and 39 feet wide (24 meters long and 12 meters wide). They were brought to the station in pairs during four space shuttle missions in 2000, 2006, 2007 and 2009, each with an estimated lifespan of about 15 years.
Since then, the solar cells on those massive array wings have degraded, as expected, and are not as efficient as they once were. The new iROSAs are designed to augment the existing arrays by being installed at an angle over the top of the legacy units.
While they shade some of the older arrays’ solar cells, the new arrays are much more efficient. Each is 60 feet long by 20 feet wide (18.2 meters long by 6 meters wide) once fully unrolled and can generate more than 20 kilowatts of power.
With six already installed, they produce more than 120 kilowatts of power. Combined with the legacy arrays, the station’s current capacity is about 250 kilowatts, according to NASA, which is roughly what the combined legacy arrays were originally capable of producing in direct sunlight.
A fourth set of iROSAs would go over the remaining two legacy arrays and ensure the ISS has enough power through its planned end of life around 2030.
“We are proud of the successful deployment of six iROSAs on the ISS to date, making it the gold standard for large-scale power generation with proven flight heritage,” said Peter Cannito, Redwire chairman and CEO, in a statement. “The continuation of the program with the award of an additional two iROSAs, bringing the total to eight arrays, is a testament to the excellence and dedication of our team and the coordination amongst our suppliers and partners.”
The technology behind iROSA was first tested via a technology demonstrator called ROSA, which was tested at the station in 2017.
Since then, the ROSA technology has been used on NASA’s Double Asteroid Redirection Test spacecraft. A much larger version is expected to be used for the Power and Propulsion Element of NASA’s Lunar Gateway outpost, set to launch as early as 2025.
Moreover, a retractable version of the ROSA technology is expected to be used for Astrobotic’s Lunar Vertical Solar Array program, which the company plans to use to enable mobile power sources on the Moon’s south pole for NASA Artemis missions.
“We are proud to be supporting Astrobotic with our groundbreaking ROSA technology for their VSAT program,” said Adam Biskner, executive vice president of Redwire, in a March 1, 2023, news release. “With this new application of ROSA technology, Redwire is continuing to provide next generation lunar infrastructure solutions for critical lunar activities, which will enable new scientific discovery, long-term operations, and humanity’s permanent presence on the Moon.”
Video courtesy of NASA
Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a website about human spaceflight called Orbital Velocity. You can find him on twitter @TheSpaceWriter.