“Homebound: NASA Astronauts Conclude Their Long Mission in Space – What Are the Health Implications of Extended Space Travel?” | Science, Climate & Tech News

Veteran astronauts Sunita “Suni” Williams and Commander Barry “Butch” Wilmore reached the International Space Station (ISS) in June 2024, believing it would be a standard eight-day mission.

Unbeknownst to them, they were about to be stranded in space for nearly nine months, as the spacecraft that ferried them there – Boeing’s Starliner – experienced multiple technical difficulties, making the return journey too dangerous.

Fortunately, they are expected to return home shortly, taking a ride on a SpaceX vehicle that will bring them back to Florida.

But what led to their prolonged absence, and what are the implications of such an extended stay in space?

What caused their predicament?

Ms. Williams and Mr. Wilmore launched on June 5 during Starliner’s inaugural crewed mission.

The mission aimed to evaluate the spacecraft, touted as a crucial alternative to SpaceX’s Crew Dragon, which is currently the only shuttle transporting US, European, Canadian, and Japanese astronauts to and from the ISS.

They arrived safely, but the capsule encountered five helium leaks, five non-responsive maneuvering thrusters, and a propellant valve that failed to fully close.

In the weeks that followed, Boeing and NASA undertook tests both in space and on the ground, utilizing a Starliner replica to resolve the issues faced by the craft.

Even as late as August, Boeing maintained optimism that the Starliner, developed under a $5 billion NASA contract, could safely return the astronauts.

However, both NASA and Boeing ultimately concluded it was too hazardous, leading to the Starliner’s unmanned return to Earth last September, leaving Ms. Williams and Mr. Wilmore behind at the ISS.

They were not alone; NASA astronaut Nick Hague and Russian cosmonaut Alexander Gorbunov joined them at the ISS in September.

How will they return, and why did it take so long?

Mr. Hague and Mr. Gorbunov arrived in a SpaceX Dragon capsule, which has four seats—two for them and two for Ms. Williams and Mr. Wilmore on their return trip.

The returning crew is scheduled to leave the ISS aboard a SpaceX rocket, with a splashdown off the Florida coast, where a recovery ship will retrieve them before they are flown back to shore.

However, their mission was planned before Ms. Williams and Mr. Wilmore found themselves stranded, as part of NASA’s SpaceX Crew 9 mission, which aimed to conduct scientific experiments and technological demonstrations aboard the ISS.

This Crew 9 team, which was initially made up of four astronauts, was reduced to accommodate Ms. Williams and Mr. Wilmore for their journey back. Instead of an immediate return, the two opted to join Crew 9’s six-month mission, extending their stay to February.

In December, their scheduled February return was further delayed due to issues with the SpaceX rocket assigned to bring them back.

Now, the four astronauts remain at the ISS, waiting for a new crew of four, NASA’s SpaceX Crew-10, to replace them before they leave on a different SpaceX vessel.

Crew 10 is on its way, and if all goes smoothly, there will be a brief transition period between the crews before Ms. Williams, Mr. Wilmore, Mr. Hague, and Mr. Gorbunov can head home.

Trump and Musk claim they have been ‘abandoned’

During their time away, Ms. Williams and Mr. Wilmore have missed a number of significant events on Earth, including Donald Trump’s defining victory over Kamala Harris.

This means they will return from the Biden administration to a Trump presidency.

This situation has led the former president to assert that the astronauts were “left” stranded in space, with tech mogul Elon Musk – who owns SpaceX – echoing that they were “abandoned for political reasons.”

As mentioned earlier, a rescue mission was never proposed for Ms. Williams and Mr. Wilmore; rather, they joined another mission.

Yet, Mr. Musk has faced scrutiny for this claim, particularly from famed astronaut Andreas Mogensen, who accused him of dishonesty.

Responding to Musk’s assertions on social media, Mr. Mogensen stated: “You know as well as I do that Butch and Suni are returning with Crew-9, as has been the plan since last September.”

“Even now, you are not sending up a rescue ship to bring them home. They are returning on the Dragon capsule that has been on the ISS since last September.”

Mr. Musk responded, reinforcing his claim: “SpaceX could have brought them back several months ago. I OFFERED THIS DIRECTLY to the Biden administration, and they refused. Return WAS pushed back for political reasons. Idiot.”

In a news briefing from space, Mr. Wilmore, 62, countered that politics did not factor into the timing of his and Ms. Williams’ return.

What are the physical impacts of space travel?

Humans have evolved over millions of years to thrive on Earth, so spending time in space—without gravity, sunlight, and with varying radiation levels—poses significant physical challenges.

The following are the primary hazards astronauts encounter in space:

Space radiation – Astronauts are subject to high-energy radiation in space, unlike on Earth, where our atmosphere and magnetic field provide protection.

This exposure can lead to DNA damage, increased cancer risk, neurodegenerative diseases, cardiovascular complications, and immune system disorders, according to experts.

The good news is that Earth’s magnetosphere—dominating the near-space environment—offers some safety due to the proximity of the ISS at 250 miles above the Earth.

In contrast, astronauts traveling beyond that, such as to the Moon (approx. 238,855 miles away), face significantly higher radiation exposure.

Microgravity effects – Floating around the space station may appear entertaining, but the absence of gravity critically disrupts bodily functions, adversely affecting human health, according to experts.

This lack of gravitational engagement can lead to two particularly troubling effects:

Firstly, astronauts typically lose bone density, causing their bones to weaken and become fragile.

Without preventative measures, NASA states that for each month spent in space, astronauts’ weight-bearing bones lose approximately 1% of their density.

Secondly, muscle atrophy—a reduction in muscle mass—occurs during their time in space.

Both bone loss and muscle atrophy are also common results of aging and sedentary living on Earth, potentially leading to serious injuries from falls, osteoporosis, and other health complications.

Additionally, gravity’s absence causes bodily fluids to shift upward, resulting in facial swelling and heightened intracranial pressure, which can impact vision.

Headaches are frequently reported by those living in space. A recent study found that 22 out of 24 surveyed astronauts who spent up to 26 weeks in space reported frequent headaches.

What psychological effects might they experience?

Living in confined environments with limited social interaction can adversely affect mental health, and astronauts accept these challenges when departing Earth.

This situation can trigger stress, sleep disturbances, declines in cognitive performance, and mood disorders, according to Afshin Beheshti, director of the Centre for Space Biomedicine at the University of Pittsburgh.

The distance from their friends and family amplifies this effect, especially given the vast gap from home.

Mr. Wilmore and Ms. Williams have openly discussed missing their loved ones in various news conferences from the ISS, expressing eagerness to reunite with them.

Are there long-lasting consequences of space travel?

While data is scarce—only around 700 people have ventured into space—existing studies suggest that most astronauts recover from most biological effects relative to their time in space.

For instance, individuals in space for five months typically require an equivalent duration for recovery from most effects.

Nevertheless, some issues may persist.

Research released in 2022 indicated bone density loss in 17 ISS astronauts on missions averaging five and a half months.

One year post-return, astronauts showed an average reduction of 2.1% in tibial bone density and 1.3% in bone strength.

Some astronauts may endure lasting vision impairments due to microgravity-induced fluid shifts and changes in intracranial pressure that affect the eyes, research indicates.

This condition is often referred to as Spaceflight-Associated Neuro-Ocular Syndrome (SANS).

For short-term missions—typically lasting just a few days in low-Earth orbit—around 95% of biological damage appears reversible upon return.

NASA astronaut Frank Rubio, who returned from a 371-day space mission in 2023, provided insight into reintegration following a lengthy absence.

Similar to Ms. Williams and Mr. Wilmore, Mr. Rubio’s six-month mission unexpectedly extended over a year due to his capsule experiencing damage.

Nearly four months after his return, he shared with Time Magazine: “The first two or three months post-return are heavily focused on [recovery], generally aiding your reintegration into Earth, your family, and rehabilitating your body.

“While adaptation to living in space happens remarkably quickly, the transition back to Earth can sometimes be longer and more challenging.

“This is largely due to gravity and its factors exerting a stronger influence on the body.”

What measures are being taken to address these negative impacts?

Researchers continue to highlight the need for more data to fully comprehend space travel’s risks, aiming to eventually establish personalized risk profiles and mitigation strategies for astronauts based on their health histories and the missions undertaken.

Significant gaps remain in understanding spaceflight’s long-term effects, particularly concerning serious implications like lung function, cancer risk, and cellular damage, which are areas of ongoing research.

Scientists also underline a lack of comprehensive insight into how all these challenges affect cognitive capabilities, mental well-being, and neuroplasticity—how the brain can adapt and change over extended periods.

NASA is consistently conducting experiments and research focused on its astronauts, primarily aimed at enhancing space travel experiences while minimizing potential side effects.

For instance, new radiation detectors are being developed to monitor crew exposure, and advanced materials are being researched to improve radiation shielding for future missions.

Unique exercise equipment on the ISS helps counter microgravity effects, supplemented by extensive research on optimal combinations of diet, exercise, and medication to ensure astronauts remain healthy during missions and upon their return to Earth.

NASA also studies individuals in isolated and confined conditions to determine robust methods of protecting astronauts against mental health challenges, continually assessing personnel.

All ongoing astronaut-related experiments and research work to mitigate health issues for the existing ISS staff and to prepare for more demanding missions to the Moon and ultimately Mars, where risks from space will be amplified.

How have the stranded astronauts been coping?

Although Mr. Wilmore and Ms. Williams initially anticipated a brief stay aboard the ISS, they have consistently asserted their readiness for an extended period if necessitated by the mission.

Both seasoned astronauts have completed two previous flights and have not reported any health concerns during their time in space.

In November, NASA released a photo of Ms. Williams that raised some public concerns regarding her health, with some suggesting she appeared to have lost a considerable amount of weight.

The 59-year-old addressed these concerns during a video interview on the New England Sports Network Clubhouse Kids Show, clarifying that any weight-loss rumors were unfounded.

She mentioned that any appearance changes could be attributed to “fluid shifts” caused by microgravity.

She asserted that she was in good health, referencing her consistent weight on NASA’s mass measuring device, which indicated no change from when she left Earth.

Moreover, she mentioned gaining muscle through various exercises to stay fit.

“My thighs are a bit bigger, my butt is somewhat larger,” she remarked. “We do a lot of squats.”

Throughout their stay, the pair has conveyed that they are in good spirits, repeatedly expressing that they “do not feel like castaways” and do not sense abandonment.

“Eventually we will want to go home,” Ms. Williams stated in January. “We’ve been away from our families for quite some time.

“However, there’s a lot to accomplish up here, and we need to complete that before we leave.”

She referred to the space station as her “happy place.”

What activities have they engaged in while in space?

Primarily, they have been living the typical life of a space inhabitant aboard the 356-foot-long ISS.

The station is equipped with its own oxygen-generating systems, recovering about 50% of the oxygen exhaled from carbon dioxide.

In terms of water, the station utilizes a urine recycling system to convert it back into drinking water, while also capturing moisture from the air produced by the crew’s breath and sweat.

Abundant food supplies are consistently available onboard, with additional provisions sent to the station multiple times since their arrival last year.

For more on their daily experiences aboard the ISS, including how they manage to sleep and use the restroom in zero gravity, check out this article from last year.

However, the astronauts have not solely focused on observing Earth; they have diligently worked, as all astronauts do on the space station.

They, along with the rest of Crew 9, have accomplished over 900 hours of research, engaging in more than 150 “unique scientific experiments and technology demonstrations” during their stay, per NASA.

Notable tasks included performing a spacewalk together in January to assist with repairs on the NICER telescope, which examines neutron stars and other cosmic phenomena.

This mission marked the first spacewalk by NASA astronauts since a previous aborted attempt due to water leaking into an airlock from an astronaut’s suit.

Below is an overview of some of the other activities the crew has undertaken:

• Assisted in growing arthrospiramicro-algae on the ISS—organisms that may help convert carbon dioxide exhaled by crew members back into oxygen.
• Utilized a new exercise device to monitor its effectiveness in preventing bone and muscle loss and improving cardiovascular health in space.
• Investigated flame spread in microgravity to enhance safety on future missions.
• Part of their mission also focused on Earth observation, adding to the collection of millions of photos taken by astronauts to document changes on our planet over time.

What do we know about the astronauts?

Mr. Wilmore is a seasoned astronaut, having completed two prior spaceflights and previously served as a captain in the US Navy.

His first expedition to space was in 2009, where he piloted a maintenance mission to the ISS, spending a total of 11 days in orbit.

From September to November 2014, he served as flight engineer for Expedition 41 and then commanded Expedition 42 from November 2014 to March 2015, totaling 167 days in space.

When on Earth, Mr. Wilmore resides in Tennessee with his wife Deanna and their two daughters, Daryn and Logan.

Ms. Williams was selected as a NASA astronaut in 1998, having a background as a US Navy pilot.

Before her space missions, she spent nine days living underwater as part of NASA’s NEEMO project, which sends astronauts, engineers, and scientists to live in Aquarius, the world’s only undersea research facility.

In addition to her current mission, she has completed two other ISS flights—one from December 2006 to June 2007 as a flight engineer and another from July to November 2012, accumulating 127 days in space.

According to NASA, Ms. Williams enjoys hiking and camping on Earth, engaging in similar activities in space, and has accomplished eight spacewalks throughout her ISS missions.

She and her husband Michael live in Massachusetts and enjoy spending time with their dogs and working on various hands-on projects.

What is the longest time anyone has spent in space?

That record belongs to Russian cosmonaut Valeri Polyakov, who spent 437 days in space during the mid-1990s.

He orbited the Earth more than 7,000 times before returning home.

Polyakov, a trained physician, aimed to demonstrate that the human body could endure prolonged spaceflight.

Upon landing, Polyakov opted not to be carried out of the Soyuz capsule, as is customary for readjusting to gravity’s effects.

Instead, he was assisted out of the capsule and walked to a nearby transport vehicle by himself.

He passed away in 2022 at the age of 80, with the cause of death undisclosed.