The ISS has been in orbit above the Earth for decades. Power for the space station and the experiments onboard comes from four pairs of solar arrays designed for a 15-year service life. Those solar arrays have been operating continuously since the first pair was deployed in December 2000. Additional array pairs were delivered in September 2006, June 2007, and March 2009.
The first pair of solar arrays has been delivering power to the ISS for more than 20 years. NASA says that while the solar array is functioning well, the current panels show signs of degradation. To ensure sufficient power is maintained for operations, NASA has announced it will be augmenting six of the eight existing power channels of the space station with new solar arrays.
Boeing is the prime contractor for space station operations, its subsidiary Spectrolab, and major supplier Deployable Space Systems will provide the new arrays. Combining the eight original, larger arrays and the smaller and more efficient new arrays will restore the power generation of each augmented array to approximately the amount generated when the original arrays were first installed. That equates to a 20 to 30 percent increase in power for space station research and operations.
The new solar arrays are a larger version of the Roll-Out Solar Array technology successfully demonstrated during a test on the space station in June 2017. The new solar arrays will be placed in front of the six current arrays and will use the existing sun tracking, power distribution, and channelization. NASA notes that the new arrays will shade slightly over half the length of the existing arrays and will be connected to the same power system to augment the existing supply. The current arrays powering the ISS can generate up to 160 kilowatts of power during orbital daytime.
About half of that power is stored in the station’s batteries for use when the station isn’t in sunlight. The new arrays will produce more than 20 kilowatts of electricity, eventually totaling 120 kilowatts of augmented power during the daytime. The remaining uncovered solar array and partially uncovered original arrays will continue to generate approximately 95 kilowatts of power for a total of up to 215 kilowatts. The solar arrays will be delivered to the ISS in pairs using the unpressurized trunk of the SpaceX Dragon cargo spacecraft during three resupply missions starting this year. The installation will require two spacewalks.