• Scientists are learning what short and long-duration space missions do to human bodies.
• Some changes are common like a puffier face, bone loss, and less sleep.
• Here are nine ways the harsh conditions of space can change the human body.

Suni Williams and Butch Wilmore returned to Earth on Tuesday after spending nine months in space.

The two were stranded on the International Space Station after their Boeing spaceship malfunctioned and they had to wait for a SpaceX spaceship to become available to bring them home.

Nine months in space isn't a record by any means, but it's long enough that Williams and Wilmore likely saw some changes to their bodies during their time on the ISS.

As with any astronaut, "there's a muscular and cardiovascular reconditioning that has to happen," Steve Stich, tk, said in a briefing after the duo splashed down in the Gulf of Mexico.

Much of what scientists are learning about how space affects the human body comes from NASA's research on astronauts staying on the ISS, like its Twins Study: a research program involving former NASA astronaut Scott Kelly, who lived in space for nearly a year, and his identical twin brother, Mark, who lived on the ground at the same time.

Indeed, Stich said, "every single crew member that we fly in orbit, we collect medical research data," including drawing blood, measuring bone density, and testing vision multiple times throughout their space mission.

The lack of gravity, higher radiation exposure, space-compatible diet, and other facts of life in orbit affected Scott's body in significant and surprising ways. While Wilmore and Williams weren't in space for as long as Scott, they likely experienced similar changes though perhaps not as extreme.

Here are nine biological oddities that researchers have found might happen to your body if you live in space for a long time.

Your body fluids shift.

When you orbit Earth, you're effectively in free-fall around the planet, and weightless. This means there's nothing to force blood and other bodily fluids toward your feet. The fluid shifting from your legs to your head in a year could fill a 2 liter bottle.

Your face looks different.

With less gravity, a lot of liquids move toward and into your head — so your face looks puffy.

Your sight could change.

For the same reason that your face puffs out, your vision might get worse due to pressure changes in the brain. Fluids near the optic nerve can push on the back of the eyeball.

Deep-space radiation might also promote cataracts and impair eyesight. Even high-flying commercial-airline workers face that risk because of the thinner atmosphere.

Your bone density can change.

If you don't exercise while in space, you could lose about 12% of your bone density in a year. Researchers are still trying to understand why this happens, though it seems to be related to how microgravity affects the tissues that makeup bones and bone cell behavior.

"The cells that build new bone slow down, while the cells that break down old or damaged bone tissue keep operating at their normal pace so that breakdown outpaces growth, producing weaker and more brittle bones," NASA says.

You get taller — until you get back to Earth.

Since gravity isn't pushing you down, fluid-filled discs between each of the bony vertebrae in your spine don't get compressed, stretching your height by about 3%. After Scott Kelly's time in space, he returned 2 inches taller than his twin brother. But returning to Earth-like gravity reverses that effect.

Your muscles can shrink.

You don't need muscles when you're weightless, so they atrophy and absorb the extra tissue. This is why physical exercise is a part of every astronaut's schedule. But nothing seems to maintain muscle mass better than the strain of living in the gravity found at Earth's surface.

You'll be sleepy.

You'd probably be sleep-deprived. Most astronauts only get 6 hours a night because sleeping in space feels weird.

Your cancer risk increases.

Radiation bombarding your body outside of Earth's protective magnetic field can increase your risk of getting cancer.

NASA currently limits astronauts' lifetime radiation exposure to 3,250 millisieverts for males, which is equivalent to about 400 CT scans of the abdomen.

Female astronauts typically have more tissue that's susceptible to radiation, so their lifetime limit is 2,500 mSv. 

Animal research suggests this threat could be worse in deep space than previously thought, though studies involving humans are needed to confirm that's also true for astronauts.

Your genetic code behaves differently.

DNA is life's basic blueprint, and genes — much like words in a cookbook — spell out the specific recipes to keep us alive. However, it's equally important when and how much those genes are expressed, or turned on and off. A lot of that has to do with a person's environment.

The Twins Study found that about 7% of Scott Kelly's genes expressed a bit differently after a year in space than they did on the ground, and didn't return to normal (or at least not quickly). The real-world ramifications of this are still being explored.

What if you die in space?

No one has ever died on the ISS. The farther humans travel from Earth, however, and the longer time they spend in space, the greater the risk is that someone could die from a medical event, a vehicle emergency like a fire, depressurization, electrical shock, or simply a lack of food and water.

According to NASA, if someone were to die in space one of the most immediate concerns would be how to ensure the safety of the rest of the crew.

"In the closed atmosphere of a space vehicle, the natural byproducts of decomposition and/or potential pathogens released during the decomposition process could contaminate the enclosed vehicle environment," NASA explains in a technical brief from 2024.

If the crew is close to Earth, like on the ISS, there are a few options, NASA says: return the body to Earth, place it in a safe orbit around Earth, or allow it to burn up in Earth's atmosphere.

Ultimately, the final decision would have to take into account multiple factors including minimizing risk to surviving crewmembers, potential forensics collection, biohazard containment, and legal jurisdiction.

If the crew are far from Earth, like on a mission to Mars, the option is to either try to preserve the body for return to Earth — which relies on the crew being able to handle the remains properly — or jettison the remains into space.

• A pod of dolphins swam around SpaceX's Crew Dragon spaceship after it splashed down Tuesday.
• Astronauts Suni Williams and Butch Wilmore were returning from nine months stuck in space.
• The dolphins made their splashdown extra special.

Shortly after a SpaceX capsule carrying four astronauts splashed down in the Gulf of Mexico on Tuesday, a pod of dolphins swarmed the spaceship.

Two of the astronauts on board the spaceship — Suni Williams and Butch Wilmore — were returning from an unexpected nine-month stint on the space station, which earned them an international reputation as "stranded" or "stuck" on the International Space Station.

The duo launched aboard Boeing's new spaceship in June but could not return to Earth as planned after the vehicle had some engine malfunctions. What was meant to be a roughly weeklong mission for them turned into nine months as they waited for their opportunity to come home with a SpaceX crew.

When they climbed aboard the SpaceX Crew Dragon spaceship on Tuesday, cruised through Earth orbit all day, and then plummeted back to Earth, they didn't know an oceanic welcoming committee would meet them.

As their spaceship bobbed in the ocean like a toasted marshmallow, smooth, gray dorsal fins began to peek above the water around it.

"Here on your screen, we can see dolphins, actually, who want to come and play with Dragon," Kate Tice, a webcast host and senior quality systems engineering manager at SpaceX, said in the livestream.

The dolphins danced around the capsule for several minutes as a SpaceX recovery crew checked the area for hazardous fumes and prepared the spaceship to get hauled onto a barge. There appeared to be at least six of them.

"That was really fun to see," Sarah Walker, the director of SpaceX Dragon mission management, said in a press call after the splashdown.

SpaceX has previously had to contend with boats of human fans getting too close to its spaceship after the capsule's first crewed flight in 2020.

The company and NASA wanted to avoid a repeat of that kerfuffle with this high-profile mission. The webcast hosts reiterated the importance of the Coast Guard-enforced safety zone around the landing area.

"We do want to stress to the public the need to respect this safety zone," Sandra Jones, NASA's webcast host, said in the livestream. "Recovering a spacecraft from the water is a hazardous task."

The dolphins paid no mind to the safety zone, though. Luckily, they didn't seem to interfere with SpaceX procedures.

It's unclear if Williams, Wilmore, and their two crewmates — Nick Hague and Russian cosmonaut Aleksandr Gorbunov — got to see the dolphins in person. The dolphins were no longer visible on the livestream by the time crews started pulling them out of the spaceship.

• SpaceX just brought home two astronauts who were stuck on the International Space Station for months.
• Their return was a fairly routine spaceflight for SpaceX.
• It's a victory Elon Musk can claim after a series of setbacks to his other ventures.

Elon Musk and his many projects have had a rough couple of months, but SpaceX nailed an undisputable win for him on Tuesday.

The rocket company's Crew Dragon spaceship splashed down in the Gulf of Mexico, carrying two NASA astronauts who were stuck on the International Space Station for about nine months.

Suni Williams and Butch Wilmore became international news after their Boeing spaceship glitched as it approached the ISS in June. NASA decided it was safer for them to fly SpaceX home. The change of plans meant they had to stay and serve a full shift with the next astronaut crew, turning their original weeklong mission into nine months.

Their safe return is a win for Musk after a series of high-profile setbacks, from exploding Starship rockets to a Tesla stock crash.

Musk did not respond to a request for comment.

Tesla and SpaceX woes

Williams' and Wilmore's return is a much-needed win for SpaceX and Musk, who is struggling recently.

Musk himself said on Fox Business that he's had "great difficulty" running his companies since taking on the Department of Government Efficiency, which was created by an executive order by President Donald Trump and aims to slash federal spending.

He didn't elaborate, but that day Tesla's stock had dropped 15%, bringing Musk's net worth down $29 billion.

Tesla has also been the subject of a series of protests, boycott efforts, and vandalism incidents in recent months. The electric vehicle company's sales have plunged in multiple countries, including the US.

That all culminated in Trump promoting Tesla cars last week on the White House lawn, where he inspected and praised five of the company's vehicles and said he would buy one.

"The Radical Left Lunatics, as they often do, are trying to illegally and collusively boycott Tesla, one of the World's great automakers, and Elon's 'baby,' in order to attack and do harm to Elon, and everything he stands for," the president wrote on Truth Social ahead of the Tesla event.

Then there's SpaceX. The company's up-and-coming Starship mega-rocket was making significant progress with each uncrewed test flight until this year, when two consecutive flights ended with premature explosions.

Those flights are experimental. In early March, however, one of the company's routine Falcon 9 rocket launches encountered an unexpected issue: The rocket's booster, which normally lands itself on a droneship for reuse, instead caught fire and toppled over after landing.

All the while, Musk has been contending with criticisms and backlash against DOGE — from legal challenges to scrutiny of its hires.

Corporate experts have told Business Insider that Musk is "way overstretched" since taking on DOGE and "may have finally reached his tipping point."

Musk claims victory

SpaceX has been scheduled to bring the two astronauts back since August, when NASA officials decided they weren't confident enough in Boeing's spaceship to return Williams and Wilmore.

Musk started teeing their return up as a new victory in January, when he said on X that President Trump had asked SpaceX to bring them home "as soon as possible."

Musk has since said on Fox News that Williams and Wilmore were "left up there for political reasons," which multiple astronauts have disputed. The day ahead of their return flight he shared a video of Wilmore saying he appreciated Musk and Trump.

Despite the hubbub, this was a pretty routine flight for SpaceX. It was the 10th time the company's Crew Dragon vehicle has returned NASA astronaut crews to Earth in the last five years — in addition to five private Crew Dragon flights.

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• Remember those two NASA astronauts who got stuck on the International Space Station for nine months?
• They're coming back to Earth on Tuesday afternoon aboard SpaceX's Crew Dragon spaceship.
• Watch Suni Williams and Butch Wilmore fall back to Earth and splash down in the ocean.

A SpaceX spaceship falling back to Earth Tuesday afternoon will be carrying precious cargo: two astronauts who have been stuck in space for nine months.

Butch Wilmore and Suni Williams were the first astronauts to fly aboard Boeing's Starliner spaceship, which carried them to the International Space Station in June. Their mission was originally set to be about eight days, since it was just a demonstration to show the spaceship could fly humans.

That didn't work out. The Starliner's engines glitched as it approached the ISS. After weeks of review, NASA decided to send Starliner back to Earth empty and wait to bring Wilmore and Williams back on a SpaceX vehicle.

Now, finally, the wait is over and they're returning home.

Watch the astronauts return live on Tuesday afternoon

Williams and Wilmore boarded the SpaceX Crew Dragon early Tuesday morning alongside their two new crewmates: NASA astronaut Nick Hague and Russian cosmonaut Aleksandr Gorbunov.

With the help of other astronauts on the ISS, they closed the spaceship's hatch, then sat suited up and buckled in as the Crew Dragon slowly backed away from the station.

They've been cruising in orbit all day, preparing for a fiery plummet back to Earth, which is set to begin at 4:45 p.m. ET, with the spaceship expected to splash down off the coast of Florida at about 5:57 p.m. ET.

Watch it in NASA's livestream, below.

Williams and Wilmore have both said that they enjoy being in space and were prepared for the possibility that their deployment would be extended, but they also said that they miss their families and friends.

"Every day is interesting because we're up in space and it's a lot of fun," Williams said in a press conference from the ISS two weeks before their return.

"The hardest part is having the folks on the ground have to not know exactly when we're coming back," Williams added.

SpaceX has already successfully flown nine astronaut crews to space and back aboard its Crew Dragon spaceship, as well as five private crewed missions.

• The two stranded astronauts, Butch Wilmore and Suni Williams, are finally coming back to Earth.
• Their spaceflight has become such a drama that Elon Musk and President Trump are commenting on it.
• Meet the two astronauts who flew to space on a Boeing ship, got stuck, and are flying SpaceX back.

Two astronauts, Butch Wilmore and Sunita Williams, are finally coming back to Earth on Tuesday. Their spaceship is scheduled to splash down off the coast of Florida at about 5:57 p.m. ET.

The duo — affectionately known as "Butch and Suni" in NASA lingo — has been thrust into the global spotlight since they flew to the International Space Station for a short stint to test Boeing's new Starliner spaceship.

They were supposed to spend about eight days on the ISS for a demonstration flight. As they approached the station in June, though, the Starliner's engines malfunctioned, kicking off the months-long saga of two stranded astronauts.

NASA tapped SpaceX to carry them home, since the company has already successfully flown nine astronaut crews. The decision was made in August, with their return scheduled for early 2025.

Elon Musk said in January that President Trump asked SpaceX to speed up that schedule.

How stuck are the astronauts?

Wilmore and Williams have served a longer-than-average, but not exceptional, shift on the ISS. They're about 100 days shy of the current record for longest US spaceflight, which astronaut Frank Rubio set just two years ago.

Though they have been stuck up there for technical and scheduling reasons, they weren't "abandoned," as Trump said on Truth Social.

After NASA sent Starliner back to Earth without them (it landed safely in the end), the duo took on the regular duties and routine of space-station staffers. They've received supply shipments from NASA and have had their SpaceX return vehicle docked at the space station since September.

NASA officials have said that the original eight-day timeline for their mission was always an estimate, and everyone involved knew it could go longer than that — though not quite this long.

Musk, however, has leapt at the opportunity for his rocket company to take over its competitor's space mission.

At Trump's behest, last month NASA shuffled around SpaceX's spaceship schedule to bring the astronauts home a few weeks earlier than planned. They're set to return to Earth aboard a SpaceX Crew Dragon ship on Tuesday.

Who is Sunita Williams?

Like many NASA astronauts, Williams and Wilmore are both decorated US Navy test pilots.

"We've both been on deployments. We're not surprised when deployments get changed," Williams said in a September call with journalists. "Our families are used to that as well."

Williams was born in Ohio and grew up in Needham, Massachusetts. She became a Naval aviator in 1989 and made a series of deployments overseas as part of a helicopter combat support unit, including for Operation Desert Shield and Operation Provide Comfort in the Persian Gulf.

She ran a detachment for Hurricane Andrew relief in Miami in 1992, then spent a few years conducting rotary aircraft test flights before becoming an instructor.

NASA selected Williams to be an astronaut in 1998, while she was deployed on the USS Saipan. She began training two months later. Her first gig at NASA was going to Moscow to work with Russia's space agency on its piece of the International Space Station.

In her wide-ranging time at NASA, Williams has also spent nine days living in an underwater habitat and flown two previous missions totaling 322 days on the International Space Station.

When asked in the September call what she missed about Earth, she said, "of course, the things that we always miss: our families. I miss my two dogs, I miss my friends."

She and her dogs live with her husband, Michael, and the couple enjoy some highly technical hobbies: working on houses, cars, and airplanes together.

Who is Barry 'Butch' Wilmore?

Wilmore is a retired US Navy captain, having spent the first part of his career flying tactical jets.

He's completed 8,000 flight hours, 663 landings on an aircraft carrier, and four operational deployments. During Operation Desert Storm, he carried out 21 combat missions from the flight deck of the USS Kennedy.

He spent some time as a flight instructor at Edwards Air Force Base, California, before NASA selected him as an astronaut in 2000.

He's previously flown two NASA missions: an 11-day mission on the Space Shuttle Atlantis in 2009 and a shift of 167 days on the International Space Station in 2014 and 2015.

Wilmore and his wife, Deanna, are originally from Tennessee. Now, the couple and their two daughters, Daryn and Logan, live in Texas.

During the September call, Wilmore cited a Bible verse about gaining strength from adversity as "how I feel about all of this."

He later added, "We deal with all types of difficulties in all types of situations and it builds a great deal of fortitude and it builds a great deal of character."

• Astronauts take hundreds of stunning photos from the International Space Station.
• This year's best snapshots reveal both Earth and space in glorious detail.
• Check out astronauts' views of eclipses, northern lights, storms, and Earth's grandest landscapes.

Every year, the International Space Station produces some of the world's best photography.

Astronauts tend to be technically skilled with a camera, yes. Many of them are engineers, after all.

Their real photography advantage, though, is the glorious view from space as they circle our planet every 90 minutes.

From blue comets and pink northern lights to snowy volcanos and winding rivers, the view 250 miles above Earth does not disappoint.

Here are the best photos of 2024 from the space station.

You simply can't beat the views from the International Space Station.

So astronauts take hundreds of photos each year.

"How would you not want to take pictures and try and share that with the rest of humanity?" NASA astronaut Matt Dominick told ABC News Radio in August.

This year brought a special treat: the bold, bright Comet Tsuchinshan-ATLAS, or Comet A3.

Of course, astronauts also get front-row seats to the northern lights, aka the aurora borealis.

In April, they watched the shadow of the moon creep across the US during the total solar eclipse.

Earth's atmosphere offers other unique spectacles, such as colorful sunsets and sunrises.

This eerie sheen is noctilucent clouds — extremely rare ice-crystal formations much higher in the atmosphere than any other cloud.

Even these gorgeous photos don't do the real views justice, according to Dominick.

"I've spent a fair amount of time trying to capture what I can see with my eye. I've not been able to achieve it yet," he said.

Not all the views are fun or comforting. Astronauts can see wildfires clearly.

Every year they get a bird's-eye view of hurricanes, too.

Stretching hundreds of miles wide, major storms like Hurricanes Helene and Milton seem to swallow the world below.

Astronauts can even see lightning blaring through the clouds.

One thing they can't often see is borders — like in this spot where Libya, Sudan, and Egypt meet in the Sahara desert.

Astronauts have long described a profound shift in perspective when they first see Earth from above. It's called the "Overview Effect."

They talk about overwhelming feelings of awe, unity, and a sense of Earth's fragility.

The actor William Shatner described it after his 2021 spaceflight with Jeff Bezos: "There's the blue down there and the black up there. There is Mother Earth and comfort, and there is — is there death? I don't know."

"It really is difficult for me to imagine people on Earth not getting along together," NASA astronaut Suni Williams told reporters in September. "It just changes your perspective."

Williams and her crewmate, Butch Wilmore, have been stuck on the space station for months.

They were the first people to fly on Boeing's Starliner spaceship for a roughly week-long flight in July.

Starliner returned to Earth without them after engine issues made NASA officials concerned about its safety.

Now, Williams and Wilmore are scheduled to return to Earth aboard SpaceX's Crew Dragon spaceship in March.

They've taken the setback in stride. "This is my happy place. I love being up here in space," Williams said.

The space station's days are numbered, though. It will reach the end of its operational life in 2030.

NASA has asked SpaceX to design a vehicle to push the ISS out of orbit, to a fiery plunge into the Pacific Ocean.

The ISS will have a "big legacy," Dominick said: "Look what humanity can do when they come together and work together."

• Two astronauts have been stuck on the space station after their Boeing spaceship had engine issues.
• Now, their return is being delayed another month to give SpaceX time to process a new spaceship.
• NASA and SpaceX are using the new ship, instead of a refurbished one, to expand SpaceX's fleet.

Two astronauts have been stuck on the International Space Station for months because of issues with Boeing's new Starliner spaceship.

Now, they'll have to stay just a bit longer because SpaceX needs extra time to prepare its Crew Dragon spaceship.

Butch Wilmore and Suni Williams were set to finally come back to Earth in February. Now the earliest they can return is in late March, NASA announced in a blog post on Wednesday.

While one month is not a terribly long delay by regular NASA mission standards, the extra time in orbit is significant considering Wilmore and Williams launched into space for a roughly eight-day mission way back in June.

SpaceX needs extra time to process a new spaceship

SpaceX's Crew-10 mission, originally scheduled for February, is supposed to relieve Wilmore and Williams and allow them to finally return home.

NASA and SpaceX recently decided, though, to use a new Dragon spaceship rather than a used, refurbished one for that launch, according to NASA's blog post.

The new spaceship will need extra time after it ships to SpaceX's processing facility in Florida in January. That's why NASA pushed back the launch date.

"Fabrication, assembly, testing, and final integration of a new spacecraft is a painstaking endeavor that requires great attention to detail," Steve Stich, the manager of NASA's Commercial Crew Program, said in a statement.

This was "the best option for meeting NASA's requirements and achieving space station objectives for 2025," the blog post said.

SpaceX has reused Dragon spaceships for NASA missions in the past. However, a NASA spokesperson told BI that certifying the new spacecraft will expand the company's Crew Dragon fleet to five human-rated spaceships, for both NASA and private missions.

In a statement sent in an email, the spokesperson said that Wilmore, Williams, and their crewmate Nick Hague were "supportive of the path forward."

They added that the three astronauts "understood the possibilities and unknowns, including being aboard station longer than planned."

SpaceX did not immediately respond to a request for comment.

SpaceX to the rescue

The question of how Wilmore and Williams would get back to Earth arose soon after their launch.

As their newly-minted Boeing Starliner ship approached the ISS in early June, it experienced engine issues that raised NASA officials' eyebrows.

After weeks of testing and deliberating, NASA decided to send the Starliner back to Earth empty. Officials weren't confident enough that it was safe.

Meanwhile, Wilmore and Williams stayed on the space station. NASA reassigned them to its next mission with SpaceX, called Crew-9. They would have a ride home on that spaceship. Two other astronauts gave up their SpaceX seats to make room for the Boeing duo.

The catch was that Wilmore and Williams would have to serve the same six-month shift as the rest of Crew-9. They've been conducting experiments and maintenance on the ISS just like everyone else, with the promise of coming home in February.

Now, they'll have to wait another month.

"We appreciate the hard work by the SpaceX team to expand the Dragon fleet in support of our missions," Stich said in the Wednesday statement, adding his appreciation for "the flexibility of the station program and expedition crews."

• The billionaire Jared Isaacman said his Polaris missions with SpaceX are "a question mark" now.
• Donald Trump nominated Isaacman for NASA Administrator months after he did SpaceX's first spacewalk.
• Space experts doubt Isaacman will fly during his NASA term, due to job demands and safety risks.

SpaceX and its go-to billionaire-turned-private-astronaut seem to be going their separate ways, at least for the next four years.

Jared Isaacman has flown two SpaceX missions to space and is slated to fly two more.

However, Isaacman may no longer fly those missions now that President-elect Donald Trump has tapped him to lead NASA.

Isaacman is the founder and CEO of a payments-processing company called Shift4, but he's more famous for conducting the world's first commercial spacewalk in September.

The spacewalk was the main feature of the first mission of the Polaris Program, which Isaacman started in partnership with SpaceX to supercharge the company's human-spaceflight capabilities as it aims for the moon and Mars.

The program is scheduled to fly two future missions, including the first human flight aboard SpaceX's Starship mega-rocket.

Isaacman has previously indicated that he would be on board that flight. It would be a crucial step in Elon Musk's plans to establish a human settlement on Mars using Starship.

The NASA nomination throws that mission into uncertainty, Isaacman acknowledged on Wednesday.

"The future of the Polaris program is a little bit of a question mark at the moment. It may wind up on hold for a moment," Isaacman said at the Spacepower 2024 conference in Orlando, according to Reuters.

Indeed, shortly after his nomination, experts told Business Insider that it was unlikely Isaacman would fly to space during his term as NASA Administrator.

"Well, it certainly has never happened before," John Logsdon, the founder of the Space Policy Institute at George Washington University, told BI.

That doesn't mean it can't happen, but Logsdon added, "NASA Administrator is a full-time, high-level government job. Taking time off to train for and carry out another spaceflight seems to me to be a little implausible."

If Isaacman wanted to fly a SpaceX mission during his NASA term, "that would take some thought on his part and the rest of the team," George Nield, a former head of the FAA's office of commercial space transportation, told BI. "What's the risk, what's the benefit, what happens if there's a bad day, and are there succession plans?"

Nield co-authored a 2020 analysis which calculated that US spaceflight has a 1% fatal failure rate, because four out of nearly 400 spaceflights have ended in deadly malfunctions. That's a rate 10,000 times greater than commercial airliners.

The US Senate has to confirm Isaacman's nomination before he can take office.

"Having the boss of the enterprise take the risk of spaceflight would be unusual, but we live in unusual times," Logsdon said.