Spacewalking astronauts worked to complete repairs to a cosmic ray detector outside the International Space Station on Saturday and give it new life.
It was the fourth spacewalk since November for NASA's Andrew Morgan and Italy's Luca Parmitano to fix the Alpha Magnetic Spectrometer. They installed new coolant pumps last month to revive the instrument's crippled cooling system and needed to check for any leaks in the plumbing.
Parmitano quickly discovered a slight leak and tightened the fittings. "Our day just got a little more challenging," Mission Control observed.
Provided everything goes well, the $2 billion spectrometer — launched to the space station in 2011 — could resume its hunt for elusive antimatter and dark matter next week, according to NASA.
NASA has described the spectrometer spacewalks as the most complicated since the Hubble Space Telescope repair missions a few decades ago. Unlike Hubble, this spectrometer was never intended for astronaut handling in orbit, and it took NASA years to devise a repair plan.
Despite their complexity, the first three spacewalks went well. Morgan and Parmitano had to cut into stainless steel pipes to bypass the spectrometer's old, degraded coolant pumps, and then spliced the tubes into the four new pumps — no easy job when working in bulky gloves. The system uses carbon dioxide as the coolant.
Besides checking for leaks Saturday, the astronauts had to cover the spectrometer with thermal insulation.
"Good luck out there, have a lot of fun," astronaut Jessica Meir radioed from inside. "We are very excited for you to be finishing off all of the amazing work that you've already put into this AMS repair, and I think everyone's excited to the prospects of what AMS has to offer once you guys finish off the work today."
The massive 7 1/2-ton (6,800-kilogram) spectrometer was launched to the space station on NASA's next-to-last shuttle flight. Until it was shut down late last year for the repair work, it had studied more than 148 billion charged cosmic rays. The project is led by Samuel Ting, a Nobel laureate at the Massachusetts Institute of Technology.
The repairs should allow the spectrometer to continue working for the rest of the life of the space station, or another five to 10 years. It was designed to operate for three years and so already has surpassed its expected lifetime.
Saturday's spacewalk got started a little late. A strap on a bag accidentally got caught in the seal when one of the inside hatches was closed and the air lock had to be reopened and repressurized before the astronauts could go out.
NASA's two other astronauts on board, Meir and Christina Koch, performed two spacewalks over the past 1 1/2 weeks to upgrade the space station's solar power system.
Altogether, this station crew has gone out on nine spacewalks.
China announced that it will launch its first Mars mission probe in July this year, China Youth Daily reported Thursday, adding that this is the first time the country disclosed the launch month of its Mars exploration program.
The Mars probe will be sent by the Long March-5 Y4 carrier rocket, said the newspaper, citing sources from the China Aerospace Science and Technology Corporation (CASC).
The Long March-5 Y4 rocket has recently completed a 100-second test for its high thrust hydrogen-oxygen engine, which is the last engine examination before the final assembly.
According to the CASC, China will send a probe to orbit and land and deploy a rover on Mars.
In 2020, the Long March-5 rocket will carry out several missions, including the Mars probe launch and the lunar sample return.
A total of 24 high thrust hydrogen-oxygen rocket engine tests will be conducted this year for these missions.
NASA's Spitzer Space Telescope, having been exploring the universe in the infrared for over 16 years, will conclude its mission on Jan. 30, said NASA's Jet Propulsion Laboratory (JPL) on Wednesday.
Launched in 2003, Spitzer revealed previously hidden features of known cosmic objects and led to discoveries and insights spanning from the solar system to nearly the edge of the universe, said the JPL in a press release.
"Spitzer taught us how important infrared light is to understanding our universe, both in our own cosmic neighborhood and as far away as the most distant galaxies," said Paul Hertz, director of astrophysics at NASA Headquarters.
"The advances we make across many areas in astrophysics in the future will be because of Spitzer's extraordinary legacy," Hertz said.
Spitzer was designed to study "the cold, the old and the dusty," three things astronomers can observe particularly well in infrared light. The telescope has studied some of the most distant galaxies ever detected.
Spitzer also has a keen eye for interstellar dust, which is prevalent throughout most galaxies, said the JPL, adding that some infrared wavelengths of light can penetrate dust when visible light cannot, allowing Spitzer to reveal regions that would otherwise remain obscured from view.
"It's quite amazing when you lay out everything that Spitzer has done in its lifetime, from detecting asteroids in our solar system no larger than a stretch limousine to learning about some of the most distant galaxies we know of," said Michael Werner, Spitzer's project scientist.
A pair of spacewalking astronauts wrapped up battery improvements outside the International Space Station on Monday, completing a job begun last fall.
NASA's Jessica Meir and Christina Koch installed the last new battery in a set of six launched to the orbiting lab in September. They also removed two old batteries in their second spacewalk in under a week to upgrade the station's solar power grid.
This marked the women's third spacewalk together. They conducted the world's first all-female spacewalk last October, replacing a failed charging device that bumped the battery replacements into this year.
The women had just completed the battery work when Koch inadvertently deployed the hand controller on her emergency jet pack, called a Safer. Meir hurried over to get the controller back in its proper place. Koch called her "my hero."
Mission Control cautioned that, given the current set-up, "we would not count on Christina's Safer" in an emergency. NASA's spacewalking astronauts always wear small Safer jet packs in case they become untethered from the station and float away. It's never been needed.
During last Wednesday's spacewalk, Koch's helmet lights and camera came loose. She later found a faulty latch in the helmet assembly and replaced it before floating out Monday.
Koch has been aboard the space station for more than 10 months, the longest single spaceflight by a woman. She returns to Earth in just over two weeks.
NASA gradually has been replacing the space station's 48 aging, original-style nickel-hydrogen batteries with new and more powerful lithium-ion batteries. Only half as many of the new batteries are needed. So far, 18 new batteries have been installed over the past three years and 36 old ones removed.
Another batch of six new batteries will be launched to the orbiting lab this spring to complete the power upgrade. The old batteries, meanwhile, will be discarded in a supply ship.
These oversized, boxy batteries keep all the space station's systems running when the outpost is on the night side of Earth, drawing power from the sprawling solar wings. They're not easy to handle: Each is about a yard, or a meter, tall and wide, with a mass of about 400 pounds (180 kilograms.)
"To our astro-sisters, we wish you the best of luck on this," astronaut Andrew Morgan radioed from inside Monday.
In all, five spacewalks were needed to complete the battery work this time around.
Morgan and Italian astronaut Luca Parmitano will venture outside Saturday to complete repairs to a cosmic ray detector on the space station. The science instrument's cooling system had to be replaced, an intricate job requiring four spacewalks.
The possibility that a new virus in central China could spread between humans cannot be ruled out, though the risk of transmission at the moment appears to be low, Chinese officials said Wednesday.
Forty-one people in the city of Wuhan have received a preliminary diagnosis of a novel coronavirus, a family of viruses that can cause both the common cold and more serious diseases. A 61-year-old man with severe underlying conditions died from the coronavirus on Saturday.
While preliminary investigations indicate that most of the patients had worked at or visited a particular seafood wholesale market, one woman may have contracted the virus from her husband, the Wuhan Municipal Health Commission said in a public notice.
The commission said the husband, who fell ill first, worked at the Huanan Seafood Wholesale Market. Meanwhile, the wife said she hasn't had any exposure to the market.
It's possible that the husband brought home food from the market that then infected his wife, Hong Kong health official Chuang Shuk-kwan said at a news briefing. But because the wife did not exhibit symptoms until days after her husband, it's also possible that he infected her.
Chuang and other Hong Kong health officials spoke to reporters Wednesday following a trip to Wuhan, where mainland Chinese authorities briefed them on the outbreak.
The threat of human-to-human transmission remains low, Chuang said, as hundreds of people, including medical professionals, have been in close contact with infected individuals and have not been infected themselves.
She echoed Wuhan authorities' assertion that there remains no definitive evidence of human-to-human transmission.
The outbreak in Wuhan has raised the specter of SARS, or severe acute respiratory syndrome. SARS is a type of coronavirus that first struck southern China in late 2002. It then spread to more than two dozen countries, killing nearly 800 people.