The International Space Station - Iss Science

The ISS was intended to be a world-class laboratory for conducting experiments under microgravity conditions. Three broad areas of research are conducted aboard the station: life sciences, biomedicine, and materials processing. The chief goal of life sciences and biomedicine research is to determine the effects on humans of long-duration space travel.

The Station's Glovebox

One of the difficulties of performing typical chemistry experiments in space is the microgravity condition. Liquids will not stay inside beakers or test tubes. The droplets float away. This could be extremely dangerous for the crew and the station's electronic components. To overcome this obstacle engineers at NASA and the European Space Agency developed an enclosed work space for the ISS called a microgravity science glovebox (MSG).

The MSG includes a pair of built-in gloves that crewmembers can use to handle tools and equipment within the box. The MSG was installed in the American Destiny module by the Expedition 5 crew. Figure 5.4 shows a slice of the cylindrical Destiny module. The experimental racks are positioned around the outside of the circle. An astronaut stands at the MSG research station.

The MSG is used to handle chemicals or burning or molten specimens in experiments involving fluid physics, materials science, biotechnology, and combustion science.

Bone Loss

Scientists have known for some time that human bones in the legs and feet undergo deterioration during prolonged stays in space. This was first discovered in Soviet and Russian cosmonauts who spent many months aboard space stations. Scientists believe that the effect is due to lack of mechanical loading in microgravity.

On Earth a person's body is pulled toward the ground by gravity. The weight of the upper body presses down on the lower body. This is called mechanical loading and it is good for the bones in the legs and feet. In a spaceship people do not experience the force of gravity or the downward load of the upper body. Also, they rarely use muscles in their legs and feet to move around. They rely much more on muscles in their arms and upper body to maneuver through hatches and accomplish tasks.

During the Russian Mir program, cosmonauts reported that the skin on the soles of their feet became very soft. They also lost muscle tone in their legs and feet due to lack of use. These factors caused them great difficulty walking when they returned to Earth. Scientists incorporated exercise regimens on the ISS to help prevent these problems. For example, stationary bicycles help crewmembers maintain foot muscle strength. However the exercises have had little effect on bone loss.

Historical data show that humans experience a rate of bone loss in space of approximately 1 to 2 percent per month. This means a bone loss of 12 to 24 percent per year. Scientists know that the bone loss problem has to be resolved before humans can make interplanetary journeys. A trip from Earth to Mars could take as long as six months. Crewmembers have to be able to walk on the planet's surface when they get there.

One of the most important biomedicine studies ongoing aboard the ISS is called Foot/Ground Reaction Forces During Spaceflight (Foot). The experiment began with an astronaut in the Expedition 6 crew. He wore an instrumented suit called a lower extremity monitoring suit, or LEMS. An astronaut wearing a LEMS is depicted in Figure 5.5. The LEMS consists of a pair of lycra pants equipped with numerous sensors that can measure the electrical activity of muscles, the angular motions of joints, and the force underneath the feet. Sensor data is recorded on a small wearable computer. The LEMS is also being worn by an Expedition 8 astronaut.

The LEMS is only one part of the Foot study. The astronauts participating in the study are subjected to extensive bone scans and tests prior to launch and after landing. Scientists hope the Foot results will help them to design new exercise equipment that can counteract bone loss in space.