Spacewalking astronauts upgrade station with new batteries

January 6, 2017 by Marcia Dunn
In this still image taken from video provided by NASA, astronaut Peggy Whitson takes a spacewalk outside the International Space Station on Friday, Jan. 6, 2016. Whitson and Commander Shane Kimbrough went spacewalking to hook up fancy new batteries on the International Space Station's sprawling power grid. (NASA via AP)

Spacewalking astronauts hooked up fancy new batteries Friday on the International Space Station's sprawling power grid.

NASA reported that all three lithium-ion batteries were up and running, a successful start to the space agency's long-term effort to upgrade the aging solar power system.

Before venturing out, Commander Shane Kimbrough and Peggy Whitson got a hand from a robot that took care of most of the grunt work—Dextre, a hulking machine with 11-foot arms.

Remotely operating Dextre outside the 250-mile-high lab, flight controllers in Houston spent the past week replacing decade-old, nickel-hydrogen batteries with the new ones. Handling all those batteries—each about half a refrigerator in size—was cumbersome and time-consuming.

On Friday, it was up to Kimbrough and Whitson to wire up three of the six new batteries delivered last month in a Japanese cargo capsule. The two made fairly quick work of it.

"I'm on a roll, right?" Kimbrough asked Whitson halfway through the job. The two were so far ahead that Mission Control assigned extra work.

Kimbrough and another crewmate will plug in three more batteries next Friday. NASA expects it will take two to three years to change out all 48 nickel-hydrogen batteries that make up the station's solar power system. The lithium-ion batteries are so efficient that only 24 will be needed, saving space for other items during supply runs.

The batteries store power that is tapped whenever the orbiting outpost is on the nighttime side of Earth.

Dextre, the station's robotic handyman, removed the old batteries and popped in the new ones in a series of maneuvers that began on New Year's Eve. The robot also loosened bolts on metal attachment plates for the new batteries, saving the spacewalkers even more time.

NASA's chief astronaut, Christopher Cassidy, said from Mission Control that sticky bolts often stymie astronauts, so everyone was grateful to turn over the chores to Dextre, short for dexterous.

Spacewalks are high-risk activities, NASA managers noted, and so reducing crew time outside is always preferable. Almost as a reminder, Mission Control's main contact for the spacewalkers was Italian astronaut Luca Parmitano, who nearly drowned in 2013 when his helmet flooded with water from his spacesuit's cooling system. He directed Kimbrough and Whitson's every move.

Most of the old batteries will be junked along with other station trash in a month, burning up in the atmosphere along with the Japanese supply ship that delivered the new batteries.

Whitson now ties the record for most spacewalks by a woman—seven. At 56, she's the world's oldest and most experienced spacewoman.

Explore further: Astronauts' No. 1 New Year's resolution: Ace spacewalks

More information: NASA: www.nasa.gov/mission_pages/station/main/index.html

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Eikka
1 / 5 (1) Jan 06, 2017
The lithium-ion batteries are so efficient that only 24 will be needed, saving space for other items during supply runs.


But will they have to be replaced more often? Nickel-hydrogen batteries have a service life of 15+ years, vs. lithium batteries with 8-9 years in light use.

https://en.wikipe..._battery
NiH2 cells using 26% potassium hydroxide (KOH) as an electrolyte have shown a service life of 15 years or more at 80% depth of discharge (DOD)

the specific property of the nickel–hydrogen battery is its long life: the cells handle more than 20,000 charge cycles[4] with 85% energy efficiency and 100% faradaic efficiency.


Lithium-ion batteries last a tenth of the cycles. The same 80% DoD will kill a good lithium cell in 2,500 cycles. Cheap cells won't do 1,000 cycles.

It seems to me they'll be ferrying a whole lot more replacement cells up there with the change.
Eikka
1 / 5 (1) Jan 06, 2017
As a point of reference, I bought a cellphone in 2009 - a simple phone that needed charging about once a week. The battery finally died in the last 6 months until it wouldn't hold a charge for a single call and the pouch was visibly expanded. The battery cell had just ~500 recharge cycles; it broke down from old age at 8 years.

This is why I think electric car owners are going to have a rude awakening a few years down the line, and why Tesla might have played it a bit too risky giving their batteries an 8 year warranty.

As to what comes to NASA, I'm sure they've figured a way to maximize lifespan and use some ultra-expensive cells with long shelf lives, but still, lithium-ion technology doesn't hold a candle to nickel-hydrogen if you're concerned about longevity.
PPihkala
not rated yet Jan 09, 2017
I don't thnk they are using the same liIon tech at ISS what are used with cell phones. Cell phone batteries don't perform very well at cold temperatures and it is very cold up there. But in any case I think that staggering the replacement over time would better ensure that not all cells fail at the same time.
Eikka
not rated yet Jan 14, 2017
Cell phone batteries don't perform very well at cold temperatures and it is very cold up there.


The cellphone example was to point out that all kinds of lithium batteries have a limited shelf-life becuse they undergo unwanted side reactions that slowly decompose the cell. You don't have to stress them at all and they still fail within a decade simply out of old age.

No battery performs very well just as it is up at the ISS since it gets to -157 C and chemical reactions slow down to a crawl. The batteries are insulated and heated/cooled.
BubbaNicholson
1 / 5 (1) Jan 14, 2017
It is thoughtless to cast multimillion dollar equipment wastefully and arrogantly into the atmosphere. Even trash in space has great value. Toilet waste has great value.
A big balloon into which the astronauts can dump trash? Keep trash in orbit to avoid the air pollution and heat contributions to global warming. An archeological tell in space anyway, a mound of garbage accompanies people wherever we dwell and space should be no different.
The cost of moving mass into space is so high, there may come a day when mere mass is valuable -- like having something to stop and absorb "Gravity"-like debris for instance, something to attract debris out of the sky to make it safer for all spacefarers.
Even poop has value in space, as "The Martian" demonstrated.
We will bring an asteroid into earth/lunar orbit one day, we can dump the big balloon of garbage there amidst the mining spoil, for future Martians to find. Ballast may benefit future space flight, too.

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