This explanation describes the observatories we are currently using to study X-rays from space. Chandra, named for Nobel prize winner Subrahmanyan Chandrasekhar, was launched from the space shuttle in 1999. Current X-ray observatories include The Rossi X-ray Timing Explorer (RXTE), named after astronomer Bruno Rossi, and The Advanced Satellite for Cosmology and Astrophysics (ASCA). The site also discusses what observatories we will use in the coming years to explore the structure and evolution of the Universe.