Luca powers up for a spacewalk

European Space Agency (ESA) astronaut Luca Parmitano is preparing to step out into space for his first spacewalk of the Beyond mission. Scheduled for 25 October, he will work with NASA astronaut Jessica Meir to replace nickel hydrogen batteries with newer lithium ion batteries and install battery adapter plates on the Space Station's Port-6 truss structure. This is a process fellow ESA astronaut Thomas Pesquet knows well, having replaced batteries on another power channel during his Proxima mission. We asked him to tell us more about the task and how the crew will prepare. Known to the crew as an EVA (Extravehicular Activity), each spacewalk is planned up to a year in advance. On Station, preparation begins around two weeks ahead, with a set of procedures called the "Road to EVA". "Preparing for a spacewalk will make up 2-3 hours of your schedule every day during this time," Thomas explains. "The crew often carry out prep in their personal time as well."

The big day
Live coverage of Luca and Jessica's spacewalk starts on NASA TV at 10:30 GMT (12:30 CEST), but the crew will begin their preparation around 6:00. And there is to be no showering, shaving, or applying deodorant for at least a day in advance, as any remnants of these products could mix with the pure oxygen inside the suit and pose a fire risk

Astronauts wear a liquid cooling garment underneath their spacesuit. This is connected to the water system that keeps them cool, or warm, by circulating water around their body. They also don a medical monitor and put a dosimeter in their pocket to measure radiation before entering the hatch.

Thomas describes the process inside the airlock as "like scuba diving in reverse", as astronauts breathe in a controlled way to rid their blood of nitrogen and adjust to lower pressure.

A third crew member, known as the Intravehicular (IV) crew member, is also isolated in the airlock, before it goes to vacuum. This person helps the astronauts with their oxygen masks and into their spacesuits, while making sure everything is checked, tethered and ready for a safe and successful sortie.

It is a role Luca will play in the two spacewalks before his, on 15 and 21 October.

Out in space
Before exiting the airlock, Thomas says, extreme focus is the overriding feeling.

"Everybody's watching, so many people have been involved in the preparation, and the risks are so much higher when you're outside the Space Station," he explains. "The only thing you can't really prepare for are the day/night cycles.

"During the night, you only have your helmet light, so you can't really see anything except what you're working on. And because you're working in all body orientations, it's easy to get disoriented. But you know you can always follow your tether back towards the hatch."

After exiting the airlock, Thomas says one astronaut will prepare the worksite while the other breaks torque on the pre-positioned adapter plates. Each astronaut will then work to install the adapter plates, needed to replace two older batteries with one new one.

The spacewalk on 25 October is the one of five scheduled for October. Even more are expected in November as Luca ventures out again with the complex task of repairing and enhancing dark matter hunter AMS-02 - a structure never designed to be maintained in orbit.

Jet taking off from Florida will launch NASA weather satellite

After a two-year delay, NASA is ready to use a jet aircraft to launch a new space weather satellite from Florida on Thursday night, weather permitting. The Ionospheric Connection Explorer or ICON satellite will help NASA understand and predict how solar flares interact with the earth's atmosphere and magnetic field, including our planet's deadly Van Allen radiation belts. The data is expected to help satellites avoid radiation.The rocket will be carried high over the Atlantic from Cape Canaveral Air Force Station on a Northrop Grumman L-1011 Stargazer aircraft. When it's about 50 to 100 miles east of Daytona Beach, it will drop a 52,000-pound Pegasus XL rocket and payload. The rocket will ignite and carry the satellite into orbit. Previous launches in 2017 and 2018 were delayed due to faulty sensors and vibrations detected from the rocket as it was carried by the jet, Northrop Grumman officials said. Those issues were corrected after lengthy, difficult testing during which engineers had to mimic the conditions of the rocket's high-altitude journey. Despite the delays, the mission is coming in at its original budget of $252 million, NASA officials said. "This satellite will help us get exactly the right physics, and you will now have a much more accurate prediction about what that solar flare is going to do," said Nicola Fox, heliophysics division director for NASA. The flight is set to take off about 8:32 p.m. Thursday. The rocket should launch after about one hour, at roughly 40,000 feet. NASA will broadcast the event starting at 9:15 p.m. The rocket itself will only fly for about 10 minutes before releasing its payload.

Weather delayed the launch Wednesday night. There's a better chance for good launch conditions Thursday night - 70 percent, according to the U.S. Air Force.

The Pegasus has launched 90 satellites on 43 previous missions, according to Northrop.

Dropping the rocket is "the most exciting part of the flight," said Phil Joyce, vice president of space launch programs at the company. A copilot on board actually pushes a switch to drop the Pegasus, if weather and all other conditions are good.

"It's dropping 52,000 pounds, but the plane still has the same lift," he said. "So the plane climbs fairly rapidly about 1,200 to 1,500 feet as the rocket drops for about 5 seconds before firing. That also gives us safety margin of distance."

NASA believes the ionosphere, where the Sun ionizes the air to create charged particles, is significantly influenced by storms in Earth's lower atmosphere. ICON will also help NASA better understand how atmospheric winds control ionospheric variability.

Northrop Grumman began air-launching Pegasus rockets in 1990, when one launched from beneath a NASA B-52 aircraft.

Pegasus launches have been conducted from six separate sites in the United States, Europe and the Marshall Islands.

A crew of seven will be on the ICON mission plane when it takes off. In case of storms or other delays, there is a 90-minute launch window.

Pressure runs high at edge of solar system

Out at the boundary of our solar system, pressure runs high. This pressure, the force plasma, magnetic fields and particles like ions, cosmic rays and electrons exert on one another when they flow and collide, was recently measured by scientists in totality for the first time - and it was found to be greater than expected. Using observations of galactic cosmic rays - a type of highly energetic particle - from NASA's Voyager spacecraft scientists calculated the total pressure from particles in the outer region of the solar system, known as the heliosheath. At nearly 9 billion miles away, this region is hard to study. But the unique positioning of the Voyager spacecraft and the opportune timing of a solar event made measurements of the heliosheath possible. And the results are helping scientists understand how the Sun interacts with its surroundings. "In adding up the pieces known from previous studies, we found our new value is still larger than what's been measured so far," said Jamie Rankin, lead author on the new study and astronomer at Princeton University in New Jersey. "It says that there are some other parts to the pressure that aren't being considered right now that could contribute." On Earth we have air pressure, created by air molecules drawn down by gravity. In space there's also a pressure created by particles like ions and electrons. These particles, heated and accelerated by the Sun create a giant balloon known as the heliosphere extending millions of miles out past Pluto. The edge of this region, where the Sun's influence is overcome by the pressures of particles from other stars and interstellar space, is where the Sun's magnetic influence ends. (Its gravitational influence extends much farther, so the solar system itself extends farther, as well.)

In order to measure the pressure in the heliosheath, the scientists used the Voyager spacecraft, which have been travelling steadily out of the solar system since 1977. At the time of the observations, Voyager 1 was already outside of the heliosphere in interstellar space, while Voyager 2 still remained in the heliosheath.

"There was really unique timing for this event because we saw it right after Voyager 1 crossed into the local interstellar space," Rankin said. "And while this is the first event that Voyager saw, there are more in the data that we can continue to look at to see how things in the heliosheath and interstellar space are changing over time."

The scientists used an event known as a global merged interaction region, which is caused by activity on the Sun. The Sun periodically flares up and releases enormous bursts of particles, like in coronal mass ejections. As a series of these events travel out into space, they can merge into a giant front, creating a wave of plasma pushed by magnetic fields.

When one such wave reached the heliosheath in 2012, it was spotted by Voyager 2. The wave caused the number of galactic cosmic rays to temporarily decrease. Four months later, the scientists saw a similar decrease in observations from Voyager 1, just across the solar system's boundary in interstellar space.

Knowing the distance between the spacecraft allowed them to calculate the pressure in the heliosheath as well as the speed of sound. In the heliosheath sound travels at around 300 kilometers per second - a thousand times faster than it moves through air.

The scientists noted that the change in galactic cosmic rays wasn't exactly identical at both spacecraft. At Voyager 2 inside the heliosheath, the number of cosmic rays decreased in all directions around the spacecraft. But at Voyager 1, outside the solar system, only the galactic cosmic rays that were traveling perpendicular to the magnetic field in the region decreased. This asymmetry suggests that something happens as the wave transmits across the solar system's boundary.

"Trying to understand why the change in the cosmic rays is different inside and outside of the heliosheath remains an open question," Rankin said.

Studying the pressure and sound speeds in this region at the boundary of the solar system can help scientists understand how the Sun influences interstellar space. This not only informs us about our own solar system, but also about the dynamics around other stars and planetary systems.

NASA opens call for Artemis lunar landers

NASA is seeking proposals for human lunar landing systems designed and developed by American companies for the Artemis program, which includes sending the first woman and next man to the surface of the Moon by 2024. The final call to industry comes after NASA issued two drafts on July 19 and Aug. 30, encouraging companies to send comments to help shape a key component of the agency's human exploration Artemis partnerships. NASA is expected to make multiple awards to industry to develop and demonstrate a human landing system. The first company to complete its lander will carry astronauts to the surface in 2024, and the second company will land in 2025. Proposals to build a landing system are due Nov. 1-an ambitious timeline consistent with the sequence of events leading to this point-however, companies have been preparing for, reviewing, and commenting on several drafts of NASA's broad agency announcement since mid-July and should be ready for this tight timeline. "In order to best accelerate our return to the Moon and prepare for Mars, we collaborated with industry on ideas to streamline the procurement process," said Marshall Smith, director of the Human Lunar Exploration Program at NASA Headquarters in Washington. "The private sector was eager to provide us feedback throughout this process, and we received more than 1,150 comments on the draft solicitations issued over the summer." Typical spaceflight hardware can take six to eight years to develop. With less than five years to land astronauts on the Moon, every word and requirement counts.

After reviewing the comments, NASA removed requirements that industry perceived as potential barriers to speed while preserving all the agency's human safety measures. For example, industry stated that delivery of a high number of formal technical reports would require a company to spend considerable resources and incur undue schedule risk.

Taking this into consideration, NASA has designed a less formal insight model that will be used for accessing critical contractor data while minimizing administrative overhead. As a result, NASA reduced the number of required contract deliverables from 116 to 37.

"Reports still are valuable and necessary, but to compromise and ease the bulk of the reporting burden on industry, we are asking for access to the companies' systems to monitor progress throughout development," said Nantel Suzuki, the Human Landing System program executive at NASA Headquarters in Washington.

"To maximize our chances of successfully returning to the Moon by 2024, we also are making NASA's engineering workforce available to contractors and asking proposers to submit a collaboration plan."

When called to accelerate its return to the Moon, NASA said it would meet this ambitious goal by "any means necessary."

The agency's preferred approach to a lunar landing is for the crew in the Orion spacecraft and the uncrewed human landing system to launch separately and meet in lunar orbit at the Gateway, which is critical to long-term exploration of the Moon. NASA wants to explore all options to achieve the 2024 mission and remains open to alternative, innovative approaches.

Another shift centered around how to best achieve sustainability on the Moon by 2028. In addition to greater performance, such as global lunar surface access and higher payload mass capacity, NASA originally required the Human Landing System to be refuelable as a means to ensure a more sustainable exploration architecture.

Multiple companies had concerns about this requirement, and NASA agreed to remove it so that industry has greater flexibility to address the more fundamental attribute of sustainability, which is long-term affordability.

"They were absolutely right," said Lisa Watson-Morgan, the Human Landing System program manager at NASA's Marshall Spaceflight Center in Huntsville, Alabama. "We are operating on a timeline that requires us to be flexible to encourage innovation and alternate approaches. We still welcome the option to refuel the landing system, but we removed it as a requirement."

NASA's Artemis program includes sending a suite of new science instruments and technology demonstrations to study the Moon, landing the first woman and next man on the lunar surface by 2024, and establishing a sustained presence by 2028. The agency will leverage its Artemis experience and technologies to prepare for the next giant leap - sending astronauts to Mars.

SLS Rocket Pathfinders Prepare Teams for One-of-a-Kind Hardware Prior to Moon Mission

NASA's Pegasus barge arrived Sept. 27 at the agency's Kennedy Space Center in Florida with the core stage pathfinder for NASA's Space Launch System (SLS) rocket. The pathfinder will be used for lift and transport practice techniques inside Kennedy's Vehicle Assembly Building to prepare for the first lunar mission of SLS and NASA's Orion spacecraft, Artemis I. The core stage pathfinder is one of three pathfinder structures used by NASA to train lift crews on best practices for moving and handling the SLS rocket flight hardware. In addition to the core stage pathfinder, there is an RS-25 engine pathfinder and a solid rocket booster pathfinder. Designed as full-scale mockups of the flight hardware, the three SLS pathfinders each reflect the shape and size of the individual components of the rocket. The number of pathfinders for the rocket allow multiple teams to use the pathfinders for different operations and procedures at several processing locations. After teams at Kennedy practice with the core stage pathfinder in the VAB, NASA's Exploration Ground Systems will begin stacking operations with the booster pathfinder structures to simulate an aft booster assembly and bottom center segment stacking operation. All this practice prepares teams for the same upcoming tasks with the actual flight hardware. Engineers previously used the core stage pathfinder in August at NASA's Stennis Space Center near Bay St. Louis, Mississippi, where crews practiced similar lift and handling procedures into the B-2 Test Stand ahead of the Green Run test series for the core stage.

"After the pathfinder lift operations were complete, the unit was installed into the B-2 Test Stand at Stennis," said Barry Robinson, B-2 Test Stand core stage test project manager at Stennis. "Among other things, the exercise helped us identify minor facility modifications early enough to provide the time needed to make the corrections prior to the arrival of the core stage flight hardware."

Equipped with the largest rocket stage NASA has ever produced and the largest twin boosters ever built for flight, the SLS rocket for the Artemis missions will be the most powerful rocket in the world, enabling astronauts in Orion to travel to the Moon's south pole. The two massive propellant tanks in the rocket's 212-foot-tall core stage power the four RS-25 engines at the bottom of the rocket. On either side of the core stage are two, five-segment solid rocket boosters. Together, the engines and the boosters will produce a combined thrust of 8.8 million pounds during launch and flight. The rocket for Artemis I will tower at 322 feet.

"Practicing operations with pathfinders offers teams hands-on experience for managing and handling the immense structures before this one-of-a-kind flight hardware arrives," Robinson said.

Because the pathfinders replicate the flight hardware, the various pathfinders validate ground support equipment, and flight hardware access techniques as well as train handlers to transport the equipment on a variety of terrains with different vehicles, like the Pegasus barge and Kennedy's mobile launcher, and demonstrate how the equipment can be integrated within facilities.

"Experience is the best teacher," said Jim Bolton, EGS core stage operations manager. "Pathfinders allow crews to practice lifting, accessing and transporting techniques that we prefer not to do for the first time with the flight hardware. Practicing with a pathfinder reduces risk and builds confidence."

As crews at Kennedy use the SLS booster and core stage pathfinders for the same processes the actual flight hardware will undergo when processed at Kennedy for Artemis I, completed flight hardware for SLS and Orion will also be delivered.

"NASA's first Artemis mission flight hardware has progressed into final assembly and integration, moving well beyond the early design and manufacturing stages of development," said Mark Prill, SLS core stage pathfinder lead. "Flight hardware for both the SLS rocket and the Orion spacecraft will continue to be delivered to Kennedy as NASA prepares for the launch of Artemis I."

NASA is working to land the first woman and the next man on the Moon by 2024. SLS, along with Orion and the Gateway in orbit around the Moon, are NASA's backbone for deep space exploration. SLS is the only rocket that can send Orion, astronauts and supplies to the Moon on a single mission.