SpaceX delivered a new batch of upgraded solar panels to the International Space Station. The International Space Station Roll Out Solar Arrays (IROSA) solar panels are a flat version that can roll out like a sleeping bag when they are installed during a future EVA.
The IROSA panels will supplement the familiar “rigid” solar panels that supply power for the space station. The ones that are being delivered on CRS-28 are expected to provide an additional 60 kW of power. Developed by a partnership between NASA and Deployable Space System, they are designed to be a less expensive and less massive option for providing power for the ISS.
Equipment onboard the SpaceX Cargo Dragon included replacement parts for the International Space Station’s water purification system and a replacement for the oxygen storage system used for EVAs.
They were delivered on a Cargo Dragon as part of the CRS-28 mission. The Falcon 9 rocket that launched CRS-28 included a first stage booster that was being used for the fifth time.
Additional cargo includes supplies such as fresh fruit, which is considered a treat among space station crews. Astronauts on the ISS typically rely on freeze-dried or otherwise easily preserved and “shelf-stable” foods for most of their diet.
CRS-28 also delivered experiments and equipment such as a sensor that can detect “blue lightning” in thunderstorms. A better understanding of “blue lightning” can improve atmospheric modeling.
Experiments also include a study of the viability of seeds produced in space. This study can improve growing techniques for vegetables that might be grown during future long-duration missions far from Earth.
Previous attempts to grow plants from seeds that have been in space include the famous “Moon Trees” grown from seeds that flew to the Moon and back on Apollo 14. Descendants of one of the original trees can still be seen at Kennedy Space Center. Some other Moon Trees remain unmarked or unidentified due to concerns that they might be stolen or vandalized.
Other experiments on CRS-28 include a study on the effects of long-duration space missions on telomeres. Telomeres are structures that protect DNA that tend to shorten with age. However, previous studies show that telomeres are often longer than expected after an increment on the International Space Station. This study will look at stem cell proliferation as one hypothetical cause of telomere lengthening during a space mission.
The International Space Station will also provide a jumping-off point for a study of permafrost thawing in the Canadian Arctic called ESSENCE. The ISS will deploy a CubeSat equipped with a camera that can observe the permafrost. Universities in Canada and Australia are sponsoring this study along with the ISS National Lab.
The ISS will also deploy a CubeSat that will study the effects of solar and cosmic radiation on geological samples. This mission could improve scientists’ understanding of asteroids’ origins. This study was designed by graduate and undergraduate students with help from middle school students.
When the Cargo Dragon returns to Earth, it will carry used hardware such as a charcoal bed assembly that removes some of the contaminants form the International Space Station’s air supply. This assembly will be refurbished for reuse. The External High-Definition Camera Assembly and the COLBERT (Combined Operational Load-Bearing External Resistance Treadmill) Data Avionics Unit are likewise being returned for repairs.
Like the Crew Dragon, SpaceX’s fleet of Crew Dragons can be refurbished and reused. The Cargo Dragon used for CRS-28 previously flew the CRS-21, CRS-23, and CRS-25 resupply missions. It is expected to spend 21 days docked to the International Space Station before undocking and returning to Earth.