The ISS Engineering Feat: Power and Cooling

ISS017 E 012652 (4 Aug. 2008) Earths horizon and station solar array panels are featured in this image photographed by an Expedition 17 crewmember on the International Space Station

ISS017-E-012652 (4 Aug. 2008) --- Earth's horizon and station solar array panels are featured in this image photographed by an Expedition 17 crewmember on the International Space Station

January 13, 2020 • By Rafe Van Wagenen

This blog post is part of “The ISS Engineering Feat” series contributed by Rafe Van Wagenen, a 10th-grade student at the Taft School in Watertown, Connecticut. Van Wagenen is interested in space and engineering and is inspired by the ISS as an engineering marvel. He wants to help others understand more about the impressive engineering involved in building and operating the ISS.

Solar panels and radiators on the International Space Station are essential to power the life support systems and experiments onboard. On November 10, 1998, the first module, the Zarya Module, was sent up along with the first solar panels and radiators. The solar array and radiator array are the literal backbone of the station but had to be assembled over multiple missions.

ISS038 E 024901 (2 Jan. 2014) A tiny representation of the sun sneaks through between a truss based radiator panel and a primary solar array panel on the Earth orbiting International Space Station in this photograph taken by one of the Expedition 38 crew members on Jan. 2, 2014. Clouds over Earth and the blackness of space share the background scene.

Media Credit: NASA

History
In 1998, the Zarya Module was the first space station module and also carried the first solar panels and radiators. Then, in 2000, the Zvezda Module carried up the next set of solar panels. On November 30, 2000, STS 97 brought the first truss system that would hold the solar panels that had been launched and assembled. For the next nine years, the space station’s solar panels and radiators were deployed and upgraded.

Why is power and cooling so important?

Power:

  • Powering in the space station is vital, and engineers had to figure out how to maximize the power from the sun. Engineers did this by having the solar panels turn to nearly always face the sun. This power allows all of the equipment on the station to run.

Cooling:

  • There are three forms of cooling on the space station: radiators that release heat, air conditioning, and reflective paneling. The reflective paneling reflects heat away from the station. The air conditioning circulates air inside the station. Radiators draw heat out of the space station to keep the station cool. All of this cooling is important for the comfort of the astronauts and also for experiments. 
EC77 8852 Piloted by astronauts Fred Haise and Gordon Fullerton, the prototype space shuttle Enterprise settles toward the main runway at Edwards Air Force Base on its final Approach and Landing Test flight on Oct. 26, 1977.

Media Credit: NASA

How were the solar arrays and radiators assembled?
The solar arrays and radiators were either sent to the space station pre-assembled on a module or launched on the space shuttle, and crew members attached the solar arrays to the station. Occasionally, the batteries need to be replaced, which is done over a few spacewalks. Assembling things in space is uniquely challenging because even simple spacewalks take hours due to the difficulty of operating in space. Every spacewalk has to be perfectly designed and practiced up until the actual spacewalk in order to be as safe and efficient as possible.

Learn more in additional posts in the “The ISS Engineering Feat” series on ISS design, solar array repair, and robotics.