An astronaut steps onto the rust-red surface of Mars, above her the expanse of the galaxy, bright against the darkness of space. Her teammates are setting up basecamp—after a seven-month journey they intend to stay for at least the next year. She wants to help, but her right upper quadrant pain from the past two days is worsening, and she knows she’s been running a low-grade fever. Suddenly, the pain intensifies, and she clutches her abdomen. Her teammates rush over and bring her back onboard their ship. An emergency-physician astronaut rapidly uses a hand-held ultrasound (US) machine to diagnose her with acute cholecystitis. Earth is seven months away, but the physician has trained for this. She takes the astronaut to the medical bay, and with the assistance of her teammates, runs labs, starts intravenous fluids and medications, and prepares to place an US-guided drain.
Aviation medicine—the predecessor of today’s space medicine—has been around since the early 1900s, when aviation first took flight. Only a few decades later, President John F. Kennedy launched the nation’s space dreams. Though the technological difficulties seemed insurmountable to some, by 1969, the United States had achieved that dream of going to the Moon and returning safely to Earth. By 1998, the first element of the International Space Station was launched, and today, space tourism is a commercial enterprise, academic and commercial endeavors are eyeing low Earth orbit, and a return to the Moon and voyaging beyond to Mars are the next steps in space travel.
But how does the human body cope with the extreme environments of space? Our understanding of the effects of space on human anatomy and physiology is ever-expanding, and space medicine has grown to fill that niche. As Kris Lehnhardt, MD, the element scientist for exploration medical capability at the NASA Johnson Space Center and an emergency physician at Baylor College of Medicine, both in Houston, notes, “Some physiologic changes that occur in space are good—for example, less muscle mass in the legs is helpful in zero-gravity. The problems often occur when you return home—or to any celestial body. If you haven’t used effective countermeasures to maintain your body in an Earth-like state, the stresses of gravity become problematic. One of our jobs is to figure out what those changes are, especially in the long term when you’re thinking about three-year missions to Mars, and to come up with appropriate countermeasures.”