Space medicine facts for kids

Dan Burbank and Anton Shkaplerov practice a medical drill in the Destiny laboratory on the International Space Station. This helps astronauts work together in a pretend emergency.

Space Medicine is a special type of medicine that helps astronauts stay healthy in space. It's all about preventing and treating health problems that could happen during space missions. Space medicine experts focus on keeping astronauts safe from things like strong forces (G-forces), weightlessness, strange air, and space radiation. They use knowledge from many areas, like how the body works in space, how to prevent sickness, and how to give emergency care. This also helps design spacecraft to be safer for people.

Another important area is Astronautical hygiene, which uses science to control dangers that could make astronauts sick. Both space medicine and astronautical hygiene work together to make sure astronauts have a safe environment. For example, long trips in space have been linked to problems like blurry vision and bone loss.

In 2015, NASA looked into health dangers for future space trips, including a human mission to Mars.

History of Space Medicine

Hubertus Strughold (1898–1987), a German scientist, came to the United States after World War II. He first used the term "space medicine" in 1948. He was the first professor of space medicine at the School of Aviation Medicine in Texas. In 1949, Strughold became the head of the Department of Space Medicine. He helped create the special pressure suit that early American astronauts wore.

In the Soviet Union, space medicine research happened at the Scientific Research Testing Institute of Aviation Medicine (NIIAM). In 1949, they started studying how people could fly safely in space. They worked on things like pressurized cabins and life support systems. Later, in 1963, the Institute for Biomedical Problems (IMBP) was started to focus on space medicine.

Animal Testing in Space

Before sending humans, space agencies used animals to learn how space travel affects the body. In September 1951, an Aerobee rocket safely brought back a monkey and mice from near space. On November 3, 1957, Sputnik 2 carried the first living animal to space, a dog named Laika. These flights showed that living things could survive in space and gave scientists important information. Later flights with cameras showed how animals reacted to high-G forces and weightlessness.

On January 31, 1961, a chimpanzee named Ham flew into space on a short trip. This flight helped prepare for astronaut Alan Shepard's mission. Ham experienced about 6.6 minutes of weightlessness. He was recovered safely with only a bruised nose. Ham's health was watched closely during his flight, and this data helped create life support systems for human astronauts.

Even today, animals like mice and ants are sent to the International Space Station (ISS). In 2014, ant colonies went to the ISS to see how they behaved in weightlessness. The ISS helps scientists study animal behavior without needing special capsules for each animal.

X-15 Rocket Plane

The North American X-15 rocket plane helped scientists study how the human body reacted to being near space. At its highest, the X-15 gave about five minutes of weightlessness. This helped create special pressure suits and systems to collect health data from pilots. This information was very useful for planning future space missions.

Project Mercury and Early Space Travel

Space medicine was very important for the United States' first human space program, Project Mercury. To protect astronauts from strong G-forces during launch and landing, they used special couches with seat belts. Experienced pilots also handled these forces better. A big concern for Project Mercury was how astronauts would feel being alone in a small cabin. Scientists worried more about mental health than physical health at first. Many animal tests showed that spaceflight could be safe if the environment was controlled.

Project Gemini and Apollo Missions

The Gemini program mostly looked at how two astronauts handled being isolated in space together. After returning from space, astronauts sometimes felt dizzy and had less strength.

The Apollo program already knew a lot about space medicine from Mercury and Gemini. They understood high and low G-forces and how to handle isolation. Apollo's main focus was on checking astronauts' health before and after flights. Some Apollo missions were even delayed because astronauts got sick. Apollo 14 started a kind of quarantine for astronauts to stop common illnesses from spreading. This program, called the Flight Crew Health Stabilization Program, is still used today.

How Space Travel Affects the Body

How weightlessness changes where fluids go in the body (this picture makes it look bigger than it is) (NASA)

Long trips into outer space, like a journey to Mars, can affect astronauts' bodies in many ways. In 2018, NASA-funded researchers found that long space journeys might damage astronauts' stomachs and intestines. Other studies also found that such trips could harm astronauts' brains and make them age faster.

In 2019, scientists reported that astronauts on the International Space Station had problems with blood flow and blood clots. This was based on a six-month study of 11 astronauts. These findings are important for future long-term spaceflights, like a mission to Mars.

Blood Clots

In 2020, a blood clot was found in an astronaut's neck vein during a long stay on the ISS. This needed treatment with blood thinners. A later study of eleven astronauts found that blood flow in their neck veins slowed down, and in two astronauts, it even flowed backward. NASA is now studying whether these changes make astronauts more likely to get blood clots.

Heart Rhythm Changes

Astronauts have sometimes had problems with their heart rhythm. Most of these were linked to existing heart conditions. However, it's not fully clear if spaceflight itself causes these issues. Doctors hope that better health checks before flight have reduced this risk. Other heart rhythm problems, like atrial fibrillation, can develop over time, so astronauts' hearts are checked regularly. Scientists are also watching to see if long periods of microgravity could cause heart rhythm problems, though this hasn't been seen yet.

Decompression Sickness in Space

When astronauts do spacewalks, they wear a space suit. This suit is like a small spacecraft filled with 100% oxygen at a much lower pressure than Earth's air. This low pressure allows astronauts to move their hands and arms easily.

Before a spacewalk, astronauts breathe 100% oxygen for several hours. This process, called "pre-breathing," helps remove nitrogen from their bodies slowly. This prevents bubbles from forming in their tissues, which can cause decompression sickness. When astronauts return to the spacecraft, the pressure goes back to normal. Decompression illness in space includes decompression sickness (DCS) and other injuries from pressure changes, called barotrauma.

Decompression Sickness (DCS)

Decompression sickness happens when nitrogen bubbles form in the body's tissues and blood. This occurs if the pressure around the body drops too quickly. In space, the risk of DCS is greatly reduced by "washing out" nitrogen from the body by breathing pure oxygen before a spacewalk. DCS can happen if an astronaut doesn't pre-breathe enough, or if they are dehydrated, tired, or have old injuries.

Symptoms of DCS in space can include chest pain, shortness of breath, coughing, unusual tiredness, dizziness, headaches, muscle pain, tingling, numbness, weak limbs, or vision problems.

To treat DCS, astronauts are put back into higher pressure in their suit, given 100% oxygen, and encouraged to drink fluids.

Barotrauma

Barotrauma is an injury to air-filled spaces in the body, like the ears, sinuses, lungs, and stomach, caused by pressure differences. It can happen if someone has a cold, allergies, or is dehydrated.

When pressure drops during a spacewalk, it can cause gas in the body to expand. This can lead to a swollen stomach, ear or sinus pain, and even tooth pain. Astronauts can relieve stomach swelling by gently massaging their belly. Ear and sinus pressure can be relieved by letting the air out. Sometimes, astronauts take decongestants or steroids before a spacewalk to help prevent these issues.

When pressure increases after a spacewalk, it can cause negative pressure in air-filled spaces. This can lead to ear or sinus pain, reduced hearing, and tooth or jaw pain. Treatment might include equalizing pressure in the ears and sinuses, using decongestants, or taking pain medicine.

Weakened Immune System

Astronauts in space often have weaker immune systems. This means they are more likely to get sick from new germs, and old viruses already in their bodies can "wake up." In space, certain immune cells (T-cells) don't work as well. NASA is studying these changes to help astronauts stay healthy.

In 2013, scientists found that microbes (tiny living things) on the International Space Station seemed to change in ways "not seen on Earth." These changes could make them grow faster and become more harmful. In 2019, NASA reported that hidden viruses in humans might become active during space missions, adding more risk for astronauts on future deep-space trips.

Higher Risk of Infection

A 2006 Space Shuttle experiment found that Salmonella typhimurium, a bacterium that causes food poisoning, became more harmful when grown in space. In 2013, scientists reported that microbes on the ISS could grow faster and become more dangerous. More recently, in 2017, bacteria were found to be more resistant to antibiotics and grow well in weightlessness. Tiny living things have even been seen to survive the vacuum of outer space. In 2018, researchers found five types of bacteria on the ISS. They said that microbes on the ISS should be watched carefully to keep astronauts healthy.

Effects of Tiredness

Human spaceflight often means astronauts have to work long hours without much rest. Studies show that not getting enough sleep can make people tired and cause them to make mistakes. People who are tired often don't even realize how much their performance is affected.

Astronauts and ground crews often suffer from lack of sleep and changes to their body's natural clock. Tiredness from not sleeping enough, changing sleep times, and too much work could lead to errors. This puts missions and the health of those on board at risk.

Loss of Balance

When astronauts leave and return to Earth's gravity, they can feel dizzy and wobbly. This is called “space sickness.” NASA is studying how changes in space affect balance—which involves the senses, brain, inner ear, and blood pressure. They hope to find treatments for balance problems on Earth and in space. For now, astronauts use medicine like Midodrine or promethazine to help with dizziness so they can do their jobs safely.

Loss of Bone Strength

Spaceflight osteopenia is the loss of bone strength that happens during human spaceflight. In weightlessness, calcium leaves the bones. After a 3–4 month trip in space, it can take about 2–3 years to get back the lost bone strength. New methods are being developed to help astronauts recover faster. Scientists are looking into:

• Diet and Exercise: These can help reduce bone loss.
• Vibration Therapy: This might help bones grow stronger.
• Medication: Some medicines could make the body produce more of the protein needed for bone growth.

Loss of Muscle Mass

In space, muscles in the legs, back, spine, and heart get weaker and smaller because they don't have to work against gravity. This is similar to how people lose muscle as they get older if they are not active. Astronauts use research in these areas to keep their muscles strong:

• Exercise: Doing resistance training for at least two hours a day can help build muscle.
• Neuromuscular Electrical Stimulation: This method uses electricity to prevent muscles from wasting away.

Vision Problems

During long space flights, astronauts can develop eye and vision changes called Space Associated Neuro-ocular Syndrome (SANS). These vision problems are a big concern for future deep space missions, like a human mission to Mars.

Brain Changes and Memory Risk

On December 31, 2012, a NASA-supported study reported that human spaceflight might harm astronauts' brains and speed up the start of Alzheimer's disease.

On November 2, 2017, scientists reported that astronauts who took trips in space had big changes in the position and structure of their brains. This was based on MRI scans. Astronauts who took longer space trips had greater brain changes.

Feeling Dizzy When Standing Up

On Earth, gravity pulls blood and other body fluids towards the lower body when you stand. In space, there's no gravity pulling fluids down. This changes how blood is distributed in the body, similar to lying down on Earth. When astronauts return to Earth, they have less blood volume, which can make them feel dizzy when they stand up. This problem has been greatly improved by astronauts drinking more fluids before landing.

Radiation Effects

How much radiation was found on the trip from Earth to Mars by the RAD on the MSL (2011–2013).

Soviet cosmonaut Valentin Lebedev, who spent 211 days in orbit in 1982, lost his eyesight due to cataracts. He said, “I suffered from a lot of radiation in space. It was all hidden back then, but now I can say that I caused damage to my health because of that flight.” On May 31, 2013, NASA scientists reported that a possible human mission to Mars might involve a big radiation risk. This was based on the amount of energetic particle radiation found by the RAD on the Mars Science Laboratory during its trip from Earth to Mars in 2011–2012.

Loss of Kidney Function

On June 11, 2024, researchers reported that "serious health risks emerge (for the kidneys) the longer a person is exposed to Galactic Radiation and microgravity." Based on their research with mice, they think astronauts on a three-year Mars mission might need dialysis machines when they return to Earth.

Sleep Problems

Spaceflight can mess up the body's natural sleep patterns. Astronauts often have irregular hormone levels, changes in body temperature, and poor sleep quality. This is a type of sleep disorder caused by the environment.

Spaceflight Practice Environments

Studying health in space is expensive and difficult. So, scientists use "spaceflight analogues" on Earth. These are places or situations that are similar to space. They are useful for studying things like the immune system, sleep, mental factors, how people perform, and telemedicine. Examples include closed rooms (Mars-500), underwater habitats (NEEMO), and stations in Antarctica (Concordia Station) and the Arctic (FMARS and Haughton–Mars Project).

Space Medicine Careers

Doctors in space medicine usually work in operations or research at NASA. More recently, they also work for private space companies that fly astronauts or space tourists.

Research doctors study specific space health problems, like vision changes in space, or focus on medical needs for future deep space missions. These doctors don't usually treat astronauts directly and might not have special training in space medicine.

Related Training and Specialties

There are only a few special training programs (fellowships) in Space Medicine. These programs should include training in areas like:

• Emergency care
• Commercial spaceflight
• Flight medicine
• Life support systems for space
• Aerospace studies
• Global health
• Hyperbaric and hypobaric medicine (dealing with pressure changes)
• Public health
• Disaster medicine
• Wilderness and extreme medicine

Space Nursing

Space nursing is a special type of nursing that studies how space travel affects people's bodies and minds. Like space medicine, it also helps us learn about nursing care for patients on Earth.

Medicine During Spaceflight

Sleep Medicine

Many astronauts use sleep aids. One 10-year study found that 75% to 78% of ISS and Space Shuttle crew members took these medications in space. Astronauts on the ISS are given 8.5 hours for sleep, but they average only 6 hours. Poor sleep can affect how well astronauts perform during the day. So, improving sleep has been a big topic for NASA research for over 50 years. Here are some ways they've tried to help astronauts sleep better:

• Light Therapy: Using different types of light to help the body's natural clock (circadian rhythm) stay on track. NASA has tried and used special light panels on the ISS that change their light throughout the day.
• Melatonin: A natural hormone that has helped astronauts fall asleep faster in orbit.
• Nonbenzodiazepines: These sleep medicines, like Zolpidem, are the most common ones used on the ISS. They may cause fewer problems the next morning than other types of sleep aids.
• Benzodiazepines: These sleep medicines are also used, but less often than nonbenzodiazepines. Some, like temazepam, can cause morning tiredness.
• Modafinil: This medicine helps people stay awake. It's available on the space station to help astronauts perform better when they are tired.

Ultrasound in Space

Ultrasound is the main way doctors can see inside the body on the ISS and for future missions. X-rays and CT scans use radiation, which is not good in space. MRI machines are too big right now. Ultrasound uses sound waves to create images and comes in laptop-sized devices. It can image many different body parts. It's used to look at the eye and optic nerve to understand vision changes in astronauts. NASA is also using ultrasound for muscle and bone problems, which are common in space.

A big challenge is training astronauts to use the ultrasound equipment and understand the images. Ultrasound technicians train for years. So, images are currently sent back to mission control on Earth for medical experts to read. For future long missions, astronauts will need to be able to use and understand ultrasounds on their own because sending data back to Earth would take too long in an emergency.

Space Shuttle Era Medical Care

With the Space Shuttle program, NASA could carry more medical supplies. The Shuttle Orbiter Medical System (SOMS) had two parts: the Medications and Bandage Kit (MBK) and the Emergency Medical Kit (EMK). The MBK had pills, bandages, and skin medicines. The EMK had injectable medicines, tools for minor surgeries, and diagnostic items.

John Glenn, the first American to orbit Earth, flew to space again on STS-95 at age 77. His flight helped study how space affects older people, looking at bone loss, muscle loss, balance problems, sleep issues, heart changes, and a weaker immune system. These are all problems that affect both aging people and astronauts.

Future Space Medicine Research

Making Long Space Flights Possible

To make longer space flights possible, NASA is investing in ways to prevent medical problems and injuries. While injuries are life-threatening, common medical issues can also be very dangerous for astronauts. If an astronaut gets sick, it can put the whole mission at risk. The small, closed environment of a spacecraft also makes it easy for diseases to spread. If an astronaut gets sick, it can affect the safety of others and make it harder to complete the mission. This becomes even more serious on longer and more complex missions.

Treating injuries might even involve surgery in zero-gravity, which is very difficult because blood and fluids float around. Diagnosing and watching astronauts' health is very important. NASA tested a device called rHEALTH ONE to help with medical monitoring in orbit and for trips to the Moon and Mars. This helps reduce the risk of health problems and performance issues during missions, as well as long-term health problems from being in space. Without good medical monitoring on board, losing crew members could put long missions in danger.

Impact on Science and Medicine

Astronauts are not the only ones who benefit from space medicine research. Many medical products have been developed that are "space spinoffs." These are practical uses for medicine that came from the space program. Because NASA works with other health organizations, space exploration has helped older people too. These spinoffs are sometimes called "exomedicine."

From Mercury to Apollo Missions

• Radiation Therapy for Cancer: NASA helped develop neutron therapy for cancer patients.
• Foldable Walkers: These lightweight walkers are made from a metal developed by NASA for aircraft and spacecraft.
• Personal Alert Systems: These devices send a signal for help when a button is pushed. They use telemetry technology developed by NASA.
• CAT and MRI Scans: These machines, used to see inside the human body, were developed with technology from NASA that helped take better pictures of the Moon.
• Neuromuscular Electric Stimulation (NMES): This treatment, first used to prevent muscle loss in space, now helps paralyzed people and athletes. It uses electrical stimulation to keep muscles strong.
• Orthopedic Evaluation Tools: NASA developed equipment to check posture, walking, and balance. They also found a way to measure bone flexibility without radiation.
• Diabetic Foot Mapping: This technique, developed at NASA, helps monitor the effects of diabetes in feet.
• Foam Cushioning: Special foam used to cushion astronauts is now used in pillows and mattresses in hospitals and nursing homes. It helps prevent sores and provides better sleep.
• Kidney Dialysis Machines: A company working with NASA developed a system to clean and recycle water for space missions. They realized this process could be used to remove waste from dialysis fluid, leading to the development of kidney dialysis machines.

Dr. Stephen Hawking used a "talking wheelchair" or the Versatile Portable Speech Prosthesis. He controlled it with a thumb switch and a blink-switch on his glasses.

• Talking Wheelchairs: These wheelchairs help people who have trouble speaking by creating computer-generated speech. This technology was first developed by NASA for aircraft. The "Talking Wheelchairs" or Versatile Portable Speech Prosthesis (VSP) project started in 1978. It was first made for people with cerebral palsy who used electric wheelchairs. The VSP is portable and easy to use with switches or a keyboard. It gives users a synthetic voice to communicate, even in crowds or in the dark. The first VSP could turn English text into speech. Users could also save and edit words.
• Collapsible, Lightweight Wheelchairs: These portable wheelchairs can be folded and put into car trunks. They use strong, light materials developed by NASA for air and spacecraft.
• Implantable Heart Pacemakers: These devices, which help regulate heartbeats, use technology developed by NASA for satellites. They can send information about how they are working.
• Implantable Heart Defibrillators: This device constantly watches heart activity and can deliver an electric shock to restore a normal heartbeat.
• EMS Communications: Technology used to send health data between Earth and space was developed by NASA to monitor astronauts. Ambulances now use this same technology to send patient information, like EKG readings, to hospitals. This helps patients get faster and better treatment.
• Weightlessness Therapy: The weightlessness of space can allow people with limited movement on Earth to move easily. Physicist Stephen Hawking experienced weightlessness in NASA's Vomit Comet aircraft in 2007. This idea also led to the Anti-Gravity Treadmill, which uses air pressure to mimic gravity.

Ultrasound in Microgravity Research

The Advanced Diagnostic Ultrasound in Microgravity Study is funded by the National Space Biomedical Research Institute. It involves astronauts, like former ISS Commanders Leroy Chiao and Gennady Padalka, using ultrasound. Experts on Earth guide them remotely to diagnose and possibly treat many medical conditions in space. This study has also helped with sports injuries and is expected to be useful for emergency and rural medical care on Earth. Findings from this study were even sent for publication from the International Space Station, making it the first article submitted from space!

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