The interplanetary Internet

Abstract

This article focuses on standardizing protocols needed for intelligent communication with and among spacecraft scattered around the solar system, as well as with robots sent to explore other planets by the U.S. National Aeronautics & Space Administration. Humans have been voyaging into space, either personally or through robotic presence, for almost 45 years. Space is an all round harsh environment, and communicating with remote spacecraft has required development of highly specialized techniques for handling very long propagation delays, extremely weak radio signal levels and stringent on board power generation limitations inherent while leaving earth. Each early space mission implemented a unique and literally handcrafted protocol for passing data back and forth between ground and spacecraft. As time and technology progressed and the number of missions increased there was a need to drastically reduce costs and allow missions to share international ground support infrastructure. Therefore, about 200 space projects with spacecraft dispersed across the solar system that have opted to use packet switching concepts for sending commands to spacecraft and transmitting measurements back to earth.