Russian and US flight controllers decided to cut short a spacewalk by two cosmonauts outside the International Space Station yesterday after voltage fluctuations in Oleg Artemyev’s Orlan spacesuit caused concern. About halfway into a scheduled seven-hour EVA, Artemeyev was repeatedly ordered to drop what he was working on and return to ISS’s airlock.
“Drop everything and start going back right away,” was one of the translated messages heard during a NASA livestream of the spacewalk. “Oleg, you must return to the airlock as soon as possible because if you lose power, it is not only the pumps and the fan, you will lose comm. You have to go back.”
NASA’s spacesuits are getting old. The extra-vehicular mobility units – EMUs for short – were designed and built for spacewalks outside NASA’s space shuttles, which flew for the last time in 2011. Nowadays, the EMUs are an integral part of maintaining and upgrading the International Space Station (ISS) exterior, providing the crew with the ability to live and work in the vacuum of space for extended periods of time (spacewalks regularly last from 6 to 8 hours). However, at the end of the most recent spacewalk on March 23, NASA astronaut Kayla Barron discovered water in the helmet of German astronaut Matthias Maurer while she helped him remove the suit.
Spacewalks are a relatively rare occurrence, and they normally draw at least a moderate amount of media coverage. So when a team of Chinese astronauts performed a spacewalk outside of their newly launched space station for the first time, it was bound to attract some notice. The successful walk installed equipment, including cameras, outside of the new Tiangong (“Heavenly Palace”) station.
In the space of just 3 days, a pair of NASA astronauts conducted an unplanned and rapidly executed contingency space walk on the exterior of the space station on Tuesday, May 23 in order to replace a critical computer unit that failed over the weekend.
The spacewalk was conducted by Expedition 51 Commander Peggy Whitson – NASA’s most experienced astronaut – and Flight Engineer Jack Fischer aboard the International Space Station (ISS).
This marked the 10th spacewalk for Whitson – who already has the most cumulative spacewalk time by a female and the most time in space by a NASA astronaut. This was Fischer’s second spacewalk.
Furthermore Whitson now moves into third place all-time for cumulative spacewalking time totaling 60 hours, 21 minutes. Only Russia’s Anatoly Solovyev and NASA’s Michael Lopez-Alegria have more spacewalking time to their credit.
NASA managers ordered the spacewalk over the weekend when a computer unit known as multiplexer-demultiplexer-1 (MDM-1) unexpectedly failed Saturday morning, May 20 at 1:13 p.m. Central time.
The cause of the MDM failure is not known, says NASA. Multiple attempts by NASA flight controllers to restore power to the MDM-1 relay box were not successful.
The US dynamic duo successfully changed out the MDM computer relay box with a spare unit on board the station. They also installed a pair of antennas on the station on the U.S. Destiny Laboratory module to enhance wireless communication for future spacewalks.
The MDM functions as a data relay box and is located on the S0 truss on the exterior of the US segment of the ISS, thereby necessitating a spacewalk by astronaut crew members.
After NASA engineers thoroughly assessed the situation and reviewed spacewalk procedures on Sunday, May 21, they gave the go ahead for Whitson and Fischer to carry out the hurriedly arranged extravehicular activity (EVA) spacewalk on Tuesday.
Meanwhile, Whitson worked on Sunday to prepare the spare data relay box and test its components to ensure it was ready for Tuesdays swap out of the failed unit.
“The relay box, known as a multiplexer-demultiplexer (MDM), is one of two units that regulate the operation of radiators, solar arrays and cooling loops.” says NASA.
“Because each MDM is capable of performing the critical station functions, the crew on the station was never in danger and station operations have not been affected.”
The two MDM’s housed in the truss are fully redundant systems.
“The other MDM in the truss is functioning perfectly, providing uninterrupted telemetry routing to the station’s systems.”
The spacewalk began Tuesday morning, May 23 at 7:20 a.m. EDT when the two NASA astronauts switched their spacesuits to battery power.
While Whitson focused on the MDM swap, Fischer worked on the antenna installation.
The unplanned spacewalk marks the second this month by Whitson and Fischer. The first was on May 12 and the 200th overall. The Destiny module antenna installation was deferred from the May 12 spacewalk.
The relatively short EVA lasted a total of two hours and 46 minutes. It concluded at 10:06 a.m. EDT.
Overall this was the 201st spacewalk in support of the space station assembly, maintenance and upgrade. Spacewalkers have now spent a total of 1,250 hours and 41 minutes working outside the orbiting lab complex since its inception.
Spacewalk 201 was also the sixth spacewalk conducted from the Quest airlock in 2017 aboard the ISS.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
This past week (on Thurs. March 30th), two crew members of Expedition 50 conducted an important spacewalk on the exterior of the International Space Station. During the seven hours in which they conducted this extravehicular activity (EVA), the astronauts reconnected cables and electrical connections on a new Pressurized Mating Adapter (PMA-3) and installed four new thermal protection shields on the Tranquility module.
These shields were required to cover the port that was left exposed when (earlier in the week) the PMA-3 was removed and installed robotically on the Harmony module. In the course of the EVA, the two astronauts – Commander Shane Kimbrough and Flight Engineer Peggy Whitson – were forced to perform an impromptu patch up job when one of the shield unexpectedly came loose.
While things flying off into space is not entirely unusual, on this occasion, there were concerns given the size and weight of the object. This shield measures about 1.5 meters by 0.6 meters (5 feet by 2 feet) and is 5 centimeters (2 inches) thick. It also weighs a little over 8 kg (18 lbs), which would make it a serious impact hazard given the relative velocity of orbital debris (28,000 km/h).
After coming loose, the bundled-up shield quickly floated away and became visible in the distance as a white dot. In response, a team from the Mission Control Center at NASA’s Johnson Space Center began monitoring the shield as it drifted. At the same time, they began working on a contingency plan to substitute the shielding, and advised the astronauts to finish covering the port with the PMA-3 cover Whitson removed earlier that day.
The plan worked, and the cover was successfully installed, providing thermal, micrometeoroid and orbital debris protection for the port. Kimbrough and Whitson finished their EVA at 2:33 pm EDT, having successfully installed the remaining shields on the berthing mechanism port. A few hours after it came loose, Mission Control also determined that the shield posed no risk to the ISS and will eventually burn up in Earth’s atmosphere.
Before concluding their spacewalk, Kimbrough and Whitson also installed what has been nicknamed a “cummerbund” around the base of the PMA-3 adapter. This cloth shield – which also provides micrometeorite protection – is so-named because it fits around the adapter in a way that is similar to how a tuxedo’s cummerbund fits around a person’s waist.
Another highlight of this spacewalk was the fact that Peggy Whitson set two new records with this latest EVA. In addition to setting the record for the most spacewalks by a female astronaut (eight), she also set the record for most accumulated time spent spacewalking – just over 53 hours – by a female astronaut. The 57-year old astronaut now ranks fifth on the list of all-time spacewalking by any astronaut.
On top of all that, Expedition 50 is Whitson’s third mission to the ISS, and she has spent a total of 500 days in space – also a record for any female astronaut. She arrived aboard the ISS aboard the Soyuz MS-03 – along with ESA flight engineer Thomas Pesquet and Roscosmos flight engineer Oleg Novitskiy – and is scheduled to return to Earth in June (though she may remain there until September).
The top spot for most accumulated time in spacewalking is currently held by Russian cosmonaut Anatoly Solovyev, who has participated in 16 spacewalks for a grand total of 82 hours spent in EVA. And in total, spacewalkers have now spent a total of 1,243 hours and 42 minutes performing 199 spacewalks in support of the assembly and maintenance of the ISS.
When it comes to being an astronaut, one of the most important requirements is flexibility – the ability to adapt to unexpected situations and come up with solutions on the fly. Crew 50 and Mission Control certainly demonstrated that this week, maintaining a tradition that brought the Apollo 13 astronauts safely back to Earth and has kept the ISS running for almost two decades.
Cosmonauts Alexander Skvortsov and Oleg Artemyev are working outside at the International Space Station today! They will spend about 6.5 hours outside installing an antenna for data relays, relocating a cargo boom, swabbing samples from a window on the Zvezda service module and switching out science experiment gear. Watch live above.
This is milestone of sorts for ISS spacewalks: it is the 180th spacewalk in support of space station construction and maintenance since December 1998, when the Russian Zarya module was mated to the US Unity node. You can read what that first spacewalk was like in an interview with astronauts Bob Cabana: What Day 1 on the International Space Station Was like for the Astronauts.
And what’s going on inside the ISS today?
Pretty neat up here right now- two Russian crew mates are spacewalking but business as usual for me and @astro_alex
UPDATE, 11:42 a.m. EDT: Rick Mastracchio and Steve Swanson finished their spacewalk in just 1 hour and 36 minutes, nearly an hour faster than what NASA budgeted for. Early tests show the replacement computer is working well, providing backup once again for the robotics, solar arrays and other systems on station.
Can two astronauts fix a broken computer quickly on the International Space Station, preventing possible problems with the solar arrays and robotics? Watch live (above) to find out.
The NASA spacewalk involving Rick Mastracchio and Steve Swanson is scheduled to start today (April 23) at 9:20 a.m. EDT (1:20 p.m. UTC), with coverage starting around 8:30 a.m. EDT (12:30 p.m. UTC). The spacewalk is scheduled to last 2.5 hours. Bear in mind that the times could change as circumstances arise.
The computer, also called a multiplexer/demultiplexer (MDM), failed for unknown reasons a couple of weeks ago. While the primary computer is working perfectly and the crew is in no danger, things get more risky if the primary computer also breaks. That’s why NASA worked to get the spacewalkers outside as quickly as possible. You can see a full briefing of the rationale here.
As a note, all non-urgent spacewalks have been suspended because NASA is still working on addressing the recommendations given after a life-threatening water leak took place in a NASA spacesuit last summer. Urgent spacewalks can still go ahead because the agency has implemented safety measures such as snorkels and helmet absorption pads in case of another leak.
Cassidy described the situation as leaking “cooling water” that got “somehow into his ventilation system” and spread into Parmitano’s helmet. The cause is still being investigated.
From a ventilation port at the back of the helmet, “the water bubbles started to build up behind this white plastic piece,” Cassidy said in the video, pointing at a support that was behind Parmitano’s head.
Update: There’s now part 2 of Cassidy’s description of the leak, below:
“Once the water got big enough that it went all the way around and started coming outside the edge of the white plastic, then it saturated his communication cap and the … flow brought the water all around his head. And he had water filled up in his ear hubs, and it started to creep into his eyes, and cover his nose.”
Calling it a “scary situation”, Cassidy said that if the leak had continued, “it would have been very serious.” NASA, however, aborted the spacewalk quickly after Parmitano reported the problem. Parmitano and Cassidy, who were outside together, were back in the International Space Station in minutes.
Parmitano, for his part, has repeatedly said that he is doing all right. “Guys, I am doing fine and thanks for all the support. I am really okay and ready to move on,” he said, as reported in a July 18 ESA blog post.
NASA has at least two probes going on: an engineering analysis to find the cause, and a more wide-ranging mishap investigation to look at spacewalk procedures and overall crew safety during spaceflights. The agency also sent a spacesuit repair kit on the Progress spacecraft that docked with the International Space Station on July 27.
The July 16 spacewalk ended after just 1 hour, 32 minutes. All of the tasks for the planned 6.5-hour outing, which included preparing data cables and power for a forthcoming Russian module, are not urgent and can be done any time, NASA said. Further American spacewalks are suspended for the time being.
Want a “you are there” view of today’s EVA that took place outside the International Space Station? Take a look at this great video of astronaut Chris Cassidy getting a ride on the station’s Canadarm-2 to make repairs and prepare for a new Russian laboratory. There are several great “over the shoulder” views during this short highlight video.
During their 6-hour and 7-minute spacewalk, Cassidy of NASA and Luca Parmitano of the European Space Agency worked on replacing a failed communications receiver, relocating grapple bars for future spacewalks and stringing cables for the when the Russian laboratory module arrives later this year.
The Ku-band communications receiver replaces one that failed last December. There was already a redundant backup system now in use, and this new one will become the backup.
The new Russian lab, called Nauka, will replace the Pirs airlock. It is scheduled to launch on a Proton rocket booster late this year, although the flight could be delayed a bit until early next year as because of assembly delays in Russia.
This spacewalk was the first of two in as many weeks for the duo. They will again venture outside the Quest airlock on July 16 for more upgrades and repairs. This was Parmitano’s first spacewalk, and he has now become the first Italian astronaut to walk in space. Old pro Cassidy has now been on five spacewalks, and this was the 170th spacewalk in support of space station assembly and maintenance.
On Monday, two Russian cosmonauts conducted a 6-hour, 34-minute spacewalk to prepare for a new Russian module that will be launched later this year. Expedition 36 Flight Engineers Fyodor Yurchikhin and Alexander Misurkin also work on the first module ever launched for the ISS – the Zarya module which has been in space since 1998 – replacing an aging control panels located on the exterior.
The new lab will be a combination research facility, airlock and docking port, and is planned to launch late this year on a Proton rocket.
Watch video highlights of the EVA below:
This was the second of up to six Russian spacewalks planned for this year to prepare for the lab. Two U.S. spacewalks by NASA’s Chris Cassidy and Luca Parmitano of the European Space Agency are scheduled in July.
While Yurchikhin and Misurkin worked outside the ISS, the crew inside the ISS were separated and isolated from each other. Cassidy and station commander Pavel Vinogradov were sequestered in their Soyuz TMA-08M spacecraft that is attached to the Poisk module on the Russian segment due to the closure of hatches to the other passageways on the Russian side of the station which would have made the Soyuz inaccessible if there was an emergency. Parmitano and US astronaut Karen Nyberg were inside the U.S. segment of the station, and were free to move around since entry to their Soyuz vehicle (TMA-09M) was not blocked by hatch closures, since it is docked to the Rassvet module that is attached to the Zarya module.
NASA said the spacewalk was the 169th in support of space station assembly and maintenance, the sixth for Yurchikhin and the first for Misurkin.