Thank you for visiting the Deep Space 1 mission status information site, frequently referred to as one of the most popular logged sources of information between the Sun and the asteroid belt on this technology validation mission. This message was logged in at 9:30 pm Pacific Time on Tuesday, December 8.

After two weeks of uninterrupted thrusting, DS1's ion propulsion system was commanded off this afternoon so that other activities could be conducted with the spacecraft. During the time that this revolutionary propulsion system was on, it changed DS1's speed by about 450 kilometers per hour, or about 280 miles per hour. At the throttle level at which the spacecraft has been for the last week, each day of thrusting added over 45 kilometers per hour, or about 30 mph. The power of ion propulsion is the terrifically low propellant consumption. During the past two weeks of operation, the spacecraft expended only about 2 kilograms of xenon, or less than 5 pounds.

This ion propulsion system is one of 12 advanced technologies being validated on DS1. The system is a product of the NASA NSTAR program, a cooperative effort between JPL and the Lewis Research Center. The industrial participants in this exciting technology are Hughes Electron Dynamics Division; Moog Inc.; Spectrum Astro Inc.; and Physical Science Inc.

After the ion propulsion system was turned off, the spacecraft successfully executed a complex pirouette to prepare it for the activation of another advanced technology. This device measures charged particles in space, both electrons and charged atoms, or ions. The alignment was required to assure that the solar wind, the stream of charged particles flowing from the Sun, would not interfere with the sensitive instrument while it was being commissioned. Later on, however, it will make detailed measurements of that same solar wind. The device combines several functions into a unit of lower mass and lower power consumption than on traditional science missions. The activation of this instrument is very complex and while it was begun today, it probably will be completed on Thursday. The unit is known as PEPE, or plasma experiment for planetary exploration. It was developed by the Southwest Research Institute in San Antonio and the Los Alamos National Laboratory. The testing of PEPE on DS1 will be another step in preparing NASA for its future of smaller, less expensive missions to explore the solar system.

Each NASA mission has a well documented set of objectives that must be satisfied. On December 2, DS1 met the criteria for minimum mission success. That was achieved by completing 200 hours of thrusting with the ion propulsion system and collecting extensive data on the performance of the advanced solar array, provided by BMDO, and the sophisticated radio system built by Motorola. While other important experiments on these and other technologies lie ahead, the mission now ranks as another success in NASA's long and impressive history of travels beyond Earth orbit.

Deep Space 1 is now 19 times as far away from Earth as the moon. Radio signals, traveling at the universal limit of the speed of light, take about 50 seconds to make the round trip.