Working over the New Year’s holiday weekend, robot arm operators at the Johnson Space Center will begin a complex procedure to replace 12 aging batteries in the International Space Station’s solar power system with six state-of-the-art lithium-ion power packs, a multi-step process over the next two weeks that will require two spacewalks to complete.
Without the remotely-controlled arm operations, it would take six spacewalks to carry out the battery swap out. But arm operators in Houston, starting New Year’s Eve, will swap out three batteries before Expedition 50 commander Shane Kimbrough and Peggy Whitson venture outside on Jan. 6 to continue the work.
After additional robot arm operations, Kimbrough and European Space Agency astronaut Thomas Pesquet will carry out a second spacewalk Jan. 13 before a final round of robot arm operations Jan. 14 and 15.
It is the most complex remotely controlled robot arm work yet implemented aboard the space station, an intricate, multi-step, multi-shift procedure that resembles a shell game of sorts, with old and new batteries moving to and fro between a cargo pallet, temporary mounting fixtures and a solar array electronics unit.
The space station is equipped with four huge sets of solar arrays that slowly rotate to track the sun as the laboratory circles the Earth. Each set of arrays powers two of the station’s eight electrical buses and each set of arrays is equipped with 12 nickel-hydrogen batteries to provide electricity when the lab is in Earth’s shadow.
Station assembly began in 1998 and the original-equipment batteries are losing strength. So, over the next few years, all 48 of the nickel-hydrogen batteries will be replaced with 24 smaller, more efficient lithium-ion batteries that will keep the station in good health through its remaining life.
The first set of six replacement batteries was carried to the station aboard a Japanese HTV cargo ship that reached the lab complex Dec. 13. Flight controllers in Houston used the station’s robot arm, equipped with a multi-appendage hand-like special purpose dexterous manipulator, or SPDM, to remove a pallet carrying the new batteries on Dec. 14.
The pallet then was maneuvered to the right side of the station’s power truss and temporarily mounted near the inboard starboard 4, or S4, set of arrays powering electrical channels 1A and 3A. The S4 arrays, and their batteries, were launched in June 2007.
Along with carrying the six new batteries to the station, the pallet will be used to carry nine of the 12 older batteries away from the station. They will burn up, along with the HTV, when the cargo ship re-enters the atmosphere after departing the station. Three of the older batteries will be left in storage aboard the lab.
Six adapter plates also were carried up on the HTV, three for electrical channel 1A and three for channel 3A. The adapter plates feature cables and circuitry to connect the new lithium-ion batteries to the station’s power grid. The three nickel-hydrogen batteries remaining on the station will be mounted atop three of the adapter plates.
Starting New Year’s Eve and continuing through Jan. 3, arm operators in Houston plan to begin the channel 3A work, moving three lithium-ion batteries from the HTV pallet to the integrated electronics assembly, or IEA, at the base of the S4 arrays. Three nickel-hydrogen batteries will be installed on the HTV pallet while a fourth will be temporarily mounted on a SPDM attachment fixture.
During U.S. EVA-38 on Jan. 6, Kimbrough and Whitson will complete the channel 3A swap-out, moving three adapter plates to the IEA and mounting two of the three nickel-hydrogen batteries that will remain in place atop those plates. Three lithium-ion batteries will already be in place thanks to earlier robotic arm operations.
Starting Jan. 8 and continuing through Jan. 12, arm operators will focus on channel 1A. Three nickel-hydrogen batteries in the electronics assembly will be moved to the HTV pallet and two more will be temporarily mounted on the SPDM. Three lithium-ion batteries will be moved from the pallet to the electronics assembly.
Kimbrough and Pesquet then will venture outside on Jan. 13, moving an adapter plate and one of the older batteries to the IEA. At this point, the three nickel-hydrogen batteries that will remain aboard the station will be in their designated positions. The astronauts will move two more adapter plates to the IEA.
Robot arm operators then will finish the battery replacement work on Jan. 14 and 15, moving the three nickel-hydrogen batteries mounted on the SPDM and a nearby attachment fitting to the HTV pallet. The pallet will be moved back to the HTV and mounted in its unpressurized cargo bay on Jan. 17. The HTV is scheduled to depart the station on Jan. 27.
With the battery replacement work out of the way, the station crew will focus on research as Kimbrough, Soyuz MS-02 commander Sergey Ryzhikov and flight engineer Sergey Borisenko wind up their stay in orbit before returning to Earth in late February.
Their replacements, Soyuz MS-04 commander Fyodor Yurchikhin and NASA flight engineer Jack Fischer, are expected to launch at the end of March.
The Russians have not yet revealed the results of an investigation to find out what triggered the loss of a Progress cargo ship Dec. 1 or what impact that might have on downstream flights.
Spacewalk on tap to replace station batteries
Two astronauts plan to venture outside the International Space Station Friday, taking over from earlier robotic arm operations to help replace a set of batteries used to store power from one of the lab’s four sets of solar arrays.
The goal is to replace 12 aging nickel-hydrogen batteries with six smaller but more powerful lithium-ion power packs that were delivered to the International Space Station last month attached to a pallet in the cargo bay of a Japanese HTV cargo ship.
Working over the New Year holiday weekend, flight controllers at the Johnson Space Center in Houston remotely operated the station’s robot arm to install three lithium-ion batteries in the integrated electronics assembly at the base of the starboard 4, or S4, set of solar arrays.
They also removed four of the older batteries from the IEA and moved three of them to the HTV pallet for eventual disposal. The fourth was temporarily mounted on a storage fixture at the base of the arm’s hand-like multi-appendage special purpose dexterous manipulator, or SPDM (pronounced SPID-um).
On Friday, Expedition 50 commander Shane Kimbrough and flight engineer Peggy Whitson will continue the multi-step replacement process during a planned six-and-a-half-hour spacewalk. A second EVA with Kimbrough and European Space Agency astronaut Thomas Pesquet is planned for Jan. 13.
Kimbrough and Whitson plan to begin their excursion at 7:05 a.m. EST (GMT-5) Friday when they switch their spacesuits to battery power inside the station’s Quest airlock.
For identification, Kimbrough, call sign EV-1, will be wearing a suit with red stripes and will use helmet camera 18. Whitson, call sign EV-2, will be wearing an unmarked suit and use helmet cam 20.
This will be the 196th spacewalk devoted to station assembly and maintenance since construction began in 1998, the third for Kimbrough and the seventh for Whitson, who has nearly 40 hours of EVA time to her credit during three previous space missions. At 56, Whitson is the oldest female space flier and the second most experienced female spacewalker after NASA’s Sunita Williams.
“All our power here on board the space station is collected by solar arrays,” Whitson said in a NASA interview. “But of course, as we’re going around the Earth 16 times in a day, half of that time the Earth is between us and the sun and so we have to have a way to store our power. Our batteries have been there in place many, many years and it’s time for us to replace (them) with new batteries outside.”
The space station is equipped with four huge sets of solar arrays that slowly rotate to track the sun as the laboratory circles the Earth. Each set of arrays powers two of the station’s eight electrical buses, or channels, and each set of arrays is equipped with 12 nickel-hydrogen batteries, six per channel, to provide electricity when the lab is in Earth’s shadow.
Station assembly began in 1998 and the original-equipment batteries are losing strength. Over the next few years, all 48 of the nickel-hydrogen batteries will be replaced with 24 smaller, more efficient lithium-ion batteries that will keep the station in good health through 2024, its currently planned end of life.
The pallet carrying the first six Li-Ion batteries, along with six so-called adapter plates, was extracted from the HTV by the station’s robot arm last month and mounted near the S4 set of arrays, which collect power for electrical channels 1A and 3A. The S4 arrays, and their batteries, were launched in June 2007.
On Friday, Kimbrough and Whitson plan to finish up the battery swap outs for channel 3A. The six original NiH2 batteries in that channel were wired in series in two-battery pairs. One Li-Ion battery and one adapter plate will replace each NiH2 battery pair, using jumper cables between the new batteries and adapter plates to maintain the serial circuit.
“We’re really looking forward to these EVAs,” Whitson said. “We’re going to use robotics to remove the old batteries and then we’ll install new batteries and adapter plates. Our new lithium-ion batteries actually are so much more efficient that we’re (installing) one battery in the volume that used to take up in two.”
Along with carrying the six new batteries to the station, the pallet will be used to carry nine of the 12 older batteries away from the station. They will burn up, along with the HTV, when the cargo ship re-enters the atmosphere after departing the station at the end of January.
Three of the older batteries will be left in storage aboard the lab, mounted atop three of the adapter plates.
After setting up their safety tethers, Kimbrough and Whitson will make their way to the S4 arrays and the HTV pallet on the right side of the station’s long power and cooling truss.
“It’s always fun to go outside,” Whitson said. “We have a great view out the cupola windows, but a lot of our time is spent focusing on the research we’re doing inside here. And so having an opportunity to go outside is very special. I’ve done a number of spacewalks out near the starboard end of the solar arrays, so it’s like going to visit an old friend out there.”
Kimbrough and Whitson first will remove two adapter plates from the HTV pallet and mount the first in the S4 integrated electronics assembly, or IEA. Then an old NiH2 battery will be removed from its place in the IEA and mounted atop the adapter plate for long-term storage. The spacewalkers will repeat that process with the second adapter plate and a second NiH2 battery.
Their final major tasks are to mount a third adapter plate in the IEA and release a bolt holding another NiH2 battery in place. Whitson and Kimbrough then will make their way back to the airlock. At that point, the channel 3A battery upgrade will be complete.
Arm operators in Houston will focus on channel 1A next week, installing the final three Li-Ion batteries. Three NiH2 batteries in the 1A section of the IEA will be moved to the HTV pallet and two more will be temporarily held by robot arm appendages.
Kimbrough and Pesquet, a French astronaut making his first spacewalk, will carry out another planned 6.5-hour spacewalk next Friday to move three adapter plates into position on the 1A side of the IEA and to mount a third and final NiH2 battery on one of those plates. If time is available, they will carry out a variety of “get-ahead” tasks before calling it a day.
With the second EVA complete, robot arm operators in Houston will finish the battery work the following week, moving the three NiH2 batteries attached to robot arm appendages to the HTV pallet for disposal. The pallet then will be moved back to the Japanese cargo ship, which is scheduled to depart the station Jan. 27.
“If we didn’t have the robotics helping us out, it would be six spacewalks for Shane and I to do all the activity,” Whitson told CBS News in an interview earlier this week. “And the reason we have to have the two is because unfortunately, the adapter plates don’t have an interface for the robotic arm. Lucky for Shane and (me)!”
Update: 12.30 MEZ
Astronauts Wrap Up Preps for Friday Spacewalk
Two Expedition 50 astronauts are in final preparations for the first of two power maintenance spacewalks that starts Friday at 7 a.m. EST. Astronauts Shane Kimbrough and Peggy Whitsonwill stow and replace power gear during the first 6.5 hour spacewalk. The duo will work near the solar arrays on the starboard truss segment.
The two spacewalkers will be assisted by ESA astronaut Thomas Pesquet and cosmonaut Oleg Novitskiy from inside the International Space Station. Pesquet will conduct the second spacewalk Jan. 13 with Kimbrough to wrap up the battery installation work. The majority of the complex power upgrade work was done by controllers on the ground remotely using the Canadarm2 robotic arm and hand.
The three cosmonauts worked on an array of station maintenance tasks and advanced space experiments. Cosmonauts Andrey Borisenko and Sergey Ryzhikov researched how blood flow and respiration is affected by living in space. Novitskiy explored the station’s magnetic field and how it affects navigation.
Update: 12.45 MEZ - Spacewalk LIVE NASA-TV: