Space programs, whether unpiloted space probes or human spaceflight missions, must be able to send large amounts of data to and from space. In the past, data might consist of navigational and spacecraft control information, radio conversations, and data collected by onboard experiments. But with today's permanent human presence in space, and for most future missions, the amount of data is much larger. For example, video transmissions are now common, and many spacecraft that conduct experiments are collecting richer sets of data over longer periods, owing in part to greater onboard data storage capacity. Hence, the major challenges in space communications of the future are handling the larger quantities of transmitted data and extending the Internet into space.

New Generation Satellites

The need to support more data transmissions has spawned the development of a new generation of space communications satellites. The mainstay...