HISTORY WRITTEN FOR CBS NEWS AND USED WITH PERMISSION
Two astronauts floated outside the International Space Station early Friday for the first of four planned spacewalks to complete a complex, multi-year job to replace 48 old batteries in the lab’s solar power system with 24 more lithium-ion units. powerful.
Starting quickly, Chris Cassidy and Robert Behnken ran well in anticipation throughout the day, completing all of their planned tasks and starting work originally planned for the series’ upcoming spacewalk next Wednesday.
“I think we have done enough for one day,” joked one of the spacewalkers before heading back to the airlock to conclude a six-hour, seven-minute excursion.
Battery replacement work started in January 2017, and based on Friday’s results, astronauts should be able to complete the job next month, ensuring reliable and trouble-free power distribution for the rest of the decade, if not longer. there.
“I think it’s safe to say that, barring any kind of unforeseen failure, we will be good with batteries for years to come,” said Kenny Todd, deputy director of the space station program at Johnson Space Center in Houston. “The longevity of the new technology batteries helps us overcome what is likely to be the end of the program.”
Floating in the Quest Lock Module, Cassidy and Behnken switched their battery-powered space suits at 7:32 am EDT to officially begin the 228th EVA in the station’s history, the fourth so far this year and the seventh for both. astronauts.
Helping with the lab’s robotic arm from inside the station were Douglas Hurley, Behnken’s crewmate aboard the SpaceX Crew Dragon shuttle that brought them into orbit last month, and cosmonaut Ivan Vagner, who launched into aboard a Soyuz on April 9 with Cassidy and cosmonaut Anatoly Ivanishin.
Floating out of the airlock, Cassidy reported that a small wrist mirror, used to help her read screens from space suits that can’t be seen directly, somehow let go and drifted away at about half a mile per hour. Tipping the scales at just a tenth of a pound, the lost mirror posed no threat to the station or crew, and Cassidy had a spare anyway.
NASA is completing the replacement of the space station’s 48 nickel-hydrogen batteries with 24 smaller but more powerful lithium-ion units, along with “adapter plates” that complete the circuit to replace the batteries that were used. removed but not replaced. The adapter plates also provide long-term storage locations for several of the old batteries.
The new batteries are arranged in sets of six in integrated electronic assemblies, or IEAs, at the bases of the station’s four main solar panel wings. Each wing is made up of two extendable solar cell blankets and the electricity they generate is delivered through the station using eight electric buses or channels, two by IEA.
The batteries in each IEA store the energy generated when the arrays are exposed to sunlight and then provide the electricity necessary to keep the station running during laboratory steps through Earth’s shadow.
The internal matrices on the right side are part of the starboard armor segment 4, or S4, which provides power to channels 1A and 3A. The internal matrices on the left side are part of the armature segment of port 4, or P4, which supplies power to channels 2A and 4A.
In 2017, spacewalkers replaced the 12 internal S4 solar panel batteries with six lithium-ion units, and in March 2019, the 12 internal P4 batteries were replaced by another six LiOH batteries.
For all of those replacements, the station’s robotic arm had the range to help astronauts relocate the batteries and unscrew, and only four spacewalks were needed. External arrangements and batteries represent a more difficult challenge.
During two spacewalks last October and another two last January, spacewalkers replaced the batteries on the far left of the station’s truss, P6, for power channels 2B and 4B. The batteries in Channel 4B were installed during NASA’s second and third female spacewalks.
Because the external job site is so far from the robot arm’s outermost anchor point, four spacewalks were required because the astronauts had to manually move the batteries back and forth between a storage pallet and the electronics assembly integrated where they were installed.
Cassidy and Behnken plan to conduct four essentially identical spacewalks to replace the 12 nickel-hydrogen batteries in the outer right-hand array array with six lithium-ion units, three powering channel 1B and three used by channel 3B. .
During Friday’s excursion, the astronauts removed five of the six previous-generation batteries in Circuit 1B, installed two new batteries, and two adapter plates. During next week’s spacewalk, the final nickel-hydrogen battery in circuit 1B will be removed and a third lithium-ion unit will be installed along with one more adapter plate.
During two spacewalks next month, Cassidy and Behnken plan to replace the batteries in power channel 3B.
But those spacewalks will depend in part on how the first two are doing and the status of plans to bring Behnken and Hurley back to Earth on the Crew Dragon ship around August 2. If problems arise, the final two spacewalks could be deferred and carried out by a future station team.
