While the main purpose of the STS-116 space shuttle mission is to get on with building the space station, the astronauts also will do an assortment of smaller experiments and hardware tests during their eleven days in space. These "secondary payloads" and Detailed Test Objectives, as NASA calls them, are the kinds of tasks that occupy the crew when they aren’t gearing up for the next spacewalk. Sometimes the inside-the-cabin sideshows can be more fun than the main event, so here’s our quick guide to a few of the less heralded happenings in and around the shuttle/space station over the next 11 days:
Space flashes: They’re called "phosphenes," the little flashes of light you see when you sneeze or rub your eyes too hard. About 80 percent of astronauts see them too, according to a survey conducted by European Space Agency mission specialist Christer Fuglesang, who’s making his first trip to orbit on STS-116. The flashes are due to charged particles in the high radiation zone of Earth orbit striking the retina, or perhaps the optic nerve or spine—no one’s certain. Astronauts typically report seeing phosphenes just before sleep. The flashes often seem to be moving diagonally or sideways, according to Fuglesang, "but never in the vertical direction." They appear to be harmless, although some space travelers say their sleep is disturbed.
To learn more about these mysterious flashes, investigators from the Italian Space Agency have designed a boxy helmet called ALTEA (Anomalous Long Term Effects in Astronaut’s Central Nervous System) equipped with silicon particle detectors and an EEG for measuring brain waves. Space station astronauts wear the ALTEA helmet for 90-minute test runs, during which incoming particles are tracked and their effects on the nervous system recorded. Fuglesang, who’s long had an interest in space radiation research and is a co-investigator for ALTEA, plans to make a video about the experiment while Discovery is docked to the station.
Fuglesang’s Frisbee: Before he became Sweden’s first astronaut, Fuglesang was a particle physicist, a sailor, and a pretty fair Ultimate Frisbee player. In fact, he once held the Swedish Frisbee record for "maximum time aloft" and was good enough to compete in the Frisbee World Championship in 1981. During this mission, as part of an educational activity for school children in Sweden, he’ll try to break the world record for time aloft, set 22 years ago by American Don Cain at 16.72 seconds. It shouldn’t be much of a challenge in zero-g, but Fuglesang will likely have to settle for spinning the Frisbee in place rather than letting fly and breaking something inside the $100 billion space station.
The MEPSI generation: Tiny satellites are all the rage these days, and several will be sprung overboard from Discovery toward the end of the mission, after the shuttle undocks from the station. One, called RAFT, was built by students at the U.S. Naval Academy, and will test the ability of the Navy’s space surveillance system to track small objects in orbit. ANDE is a pair of 18-inch satellites designed to measure the density of the thin upper atmosphere. A third experiment, called MEPSI (for Microelectromechanical System-Based (MEMS) PICOSAT Inspector), is meant to advance the art of robotic satellite inspection. A pair of MEPSI Cubesats—each measuring four inches on a side—will be ejected from a container in Discovery’s cargo bay, connected by a 50-foot tether. One of the satellites is equipped with six cameras, and will fly around the other, transmitting pictures to the ground. The hope is that some day, cheap satellites like these can be used to inspect larger, more expensive ones in orbit. The MEPSIs onboard Discovery are improved versions of ones that flew on the STS-113 mission four years ago.
Brainy bowling balls: Satellites aren’t just getting smaller, they’re becoming smarter and more cooperative. The first of three bowling ball-size satellites called SPHERES (Synchronized Position Hold, Engage, Reorient, Experimental Satellites) arrived on the space station last April, and Discovery is bringing up a third (yellow) free-flyer to go with the blue and red ones already on board. After the shuttle leaves, astronauts on the station will conduct a variety of tests with SPHERES inside the U.S. laboratory module. On the ground, engineers are limited to testing the satellites’ motion in two dimensions on air-bearing floors. In weightlessness, the astronauts can really put them through their paces. At this early stage of testing, the SPHERES won’t be allowed to wander unsupervised through the space station, but they will move around the lab (using small carbon dioxide thrusters) while sensing their position relative to each other and to beacons on the station. They’ll also "dock" to one another using velcro attachments. Formation-flying satellites will be useful for future applications ranging from astronomy to measuring the Earth’s magnetic field.
Relief for the woozy space traveler: NASA used to promise that space research would lead to all sorts of new drugs for treating maladies here on Earth. In practice it’s been more the other way around. Mainstream pharmaceutical research has produced drugs like Phenergan, which has been a big relief to astronauts suffering from space sickness during their first few days in orbit. On STS-116, medical researchers will continue their evaluation of Midodrine, approved by the FDA in 1996 as a treatment for low blood pressure. It also appears to help combat orthostatic hypotension, a condition that afflicts one in five space travelers with lightheadedness when returning to normal gravity. (Ever wonder why astronauts wait so long to come wobbling down the stairs after the shuttle lands?) The condition is even more pronounced after a six-month stay on the space station, and for some reason it affects women more than men. Just before Discovery returns to Earth, the astronauts will pop a 10-milligram tablet of Midodrine. Tests so far show that it helps to relieve post-landing wooziness, and doesn’t appear to have negative side effects.
Dear diary: The experiment that probably demands more of a space station crew’s time than any other is one the public never sees: keeping private journals. Some astronauts, like the current space station commander, Michael Lopez-Alegria, write online diaries to share their experience with the public. The journals written for behavioral scientists, though, are strictly confidential. Jack Stuster, an anthropologist and human factors specialist with Anacapa Sciences in Santa Barbara, California, has had station astronauts scribbling down their private thoughts for the past three years, hoping to learn more about what psychological and social factors are important on long-term space missions. Stuster, who’s working under a NASA research contract, has conducted similar journal studies for scientific expeditions based in the Antarctic and other remote locations where the crews experience isolation and confinement. The astronauts for the most part enjoy keeping diaries and even find it therapeutic, says Stuster, who has come up with a short, admittedly non-scientific personality quiz for would-be astronauts. Among the things he’s learned so far: Trivial problems are sometimes blown out of proportion in the close confines of a space station. But overall, he says, "people are enormously adaptive and resilient."