10 Common Digestive Disorders. The spleen is part of the lymphatic system, which plays a role in immunity and maintenance of healthy blood cells. It is an important organ and is affected by disorders of the blood, liver, and immune system. An enlarged spleen is known as splenomegaly. Although hepatosplenomegaly often produces no symptoms, it is known to cause abdominal pain in the upper portion of your abdomen.
NASA is sending astronaut Scott Kelly to live on the International Space Station for a year. That's the longest any U.S. astronaut has spent in space and twice as long as crew members usually stay on the space station. A year is a long time to stay anyplace. But staying a year in space has some special challenges.
The U.S. space shuttle program retired in 2011, leaving American astronauts to hitchhike into orbit. But after three long years, NASA's successor is almost ready to make an entrance. Orion, the agency's newest manned spaceship, is being prepared for its first mission in December. In future missions, it will journey into deep space -- to Mars and beyond -- farther than humans have ever gone before.