Challenges of Space Travel: Why Journeying to Space is So Difficult

A six-month mission on the International Space Station (ISS) presents various challenges for astronauts. Research indicates that while they can temporarily grow up to 2 inches taller, this growth is often accompanied by muscle deterioration and back pain. For further details, refer to this new research.

Astronauts have reported experiencing back pain since the late 1980s due to longer missions. In-flight medical data shows that over half of U.S. astronauts suffer from back pain, especially in the lower back, with as many as 28% reporting moderate to severe pain lasting for the duration of their mission.

Unfortunately, returning to Earth’s gravity does not alleviate these issues. Studies suggest that astronauts are 4.3 times more likely to develop herniated discs within the first year post-mission.

Dr. Douglas Chan, the lead author of a recent study and associate professor of orthopedic surgery at the University of California, San Diego, emphasizes that addressing these issues is crucial: “This is an ongoing problem that poses serious concerns.”

It’s Like Being in a Body Cast

Research is focusing on the intervertebral discs—the shock-absorbing material between vertebrae—as a key factor in astronaut back pain. However, new findings challenge this notion. In a NASA-funded study, researchers found minimal changes in disc height or bulging.

The study revealed significant degeneration and atrophy of the lumbar spine’s supportive muscles in six astronauts who were aboard the ISS for four to seven months. These muscles are critical for maintaining stability and mobility in gravity, while also protecting discs and ligaments from injury.

In a microgravity environment, the torso elongates due to reduced spinal loading, leading to flattened vertebral curvature. The lack of lower back muscle tension also contributes to pain and stiffness, akin to being immobilized in a cast for extended periods.

MRI scans conducted pre- and post-mission revealed that astronauts lost about 19% of their muscle mass during the flight. Despite undergoing six weeks of recovery training on Earth, they only regained approximately 68% of that loss, as noted by Dr. Chan.

Chan’s research team warns that this muscle atrophy is a critical concern for long-term space missions, particularly with potential trips to Mars that could last eight to nine months, exposing astronauts to further risks of muscle weakness.

Future studies will explore neck-related issues that may lead to additional muscle atrophy and slower recovery rates. Researchers aim to collaborate with other institutions to perform in-flight spinal ultrasound examinations to monitor astronaut health on the ISS.

To combat back pain and muscle loss, Dr. Chan recommends that astronauts augment their two to three hours of daily exercise with a core-strengthening program targeting spinal health.

In addition to using the “fetal tuck” position to stretch their hips and alleviate back pain, Chan advocates for incorporating yoga routines, though he acknowledges that this is challenging in microgravity.

Many yoga postures rely on gravity to provide benefits, making them difficult to perform in a weightless environment; for example, the downward dog position helps with stretches that become less effective without gravitational pull.

Equipment on the ISS must account for weight, size, and unique conditions, including potential reverberations in the spacecraft’s confined space.

Dr. Chan and his team have collaborated with virtual reality experts to develop engaging exercise programs that allow astronauts to include friends and family in their workouts, making the routines more enjoyable and competitive.

One team member, Dr. Scott Parazynski—the only astronaut to successfully summit Mount Everest—experienced a herniated disc after returning from the ISS. Following rehabilitation, he successfully climbed Everest and is now advising active astronauts on health research in microgravity.

Dr. Chan emphasizes the importance of maintaining astronaut health: “It is imperative that we take every possible measure to ensure their well-being.”

“Upon their return, astronauts gaze upon our beautiful blue planet and realize how fragile it is. They return with a new perspective on their role and place in the cosmos,” he adds.

“Our commitment to expanding our understanding of space is unyielding, as is our dedication to ensuring the well-being of the next crew,” says Chan.