Thank you for visiting the Deep Space 1 mission status information site, already ranked as the Milky Way galaxy's most authoritative source in 1999 for information on this technology validation mission. This message was logged in at 10:45 am Pacific Time on Monday, January 11.

Deep Space 1's autonomous navigation system successfully turned the ion propulsion system off on Tuesday of last week. The autonomous navigation system, known to its close friends as AutoNav, had been at DS1's helm during the holidays, updating the ion propulsion system thrust level every 12 hours. It also updated the spacecraft orientation every 12 hours so that thrusting would be in the direction AutoNav needed. On Thursday, AutoNav successfully conducted another optical navigation imaging session, during which it turned the spacecraft to point sequentially at 4 asteroids. It took 6 pictures in each direction. Later in the mission, AutoNav will analyze such images to determine where the spacecraft is. For now, the pictures are being analyzed here on Earth while AutoNav's designers at JPL improve the on-board computer routines. Previously, all they had were prelaunch predictions of the camera's performance; now, with actual images, the routines can be updated. AutoNav's successful control over the camera and the ion propulsion and attitude control systems is helping to move NASA toward an exciting future in which many of the responsibilities normally fulfilled by human controllers will be transferred to intelligent spacecraft.

The ion propulsion system now has accumulated over 850 hours, or more than 35 days, of operation. Its thrust is extremely gentle. If you hold a single sheet of paper in your hand, the weight of the paper you feel is comparable to how hard this exotic system pushes on the spacecraft. But hour after hour, day after day, the thrust does build up. The accumulated thrust during this time was enough to increase DS1's speed by nearly 900 miles per hour. Now that the ion propulsion system is turned off, the operations team will turn its attention to other technology tests. Thrusting will resume in March.

Another of DS1's new technologies is the plasma experiment for planetary exploration, affectionately known as PEPE. This device measures charged particles in space, both electrons and charged atoms, or ions. It combines several functions into a unit of lower mass and lower power consumption than on traditional science missions. PEPE was developed by the Southwest Research Institute in San Antonio and the Los Alamos National Laboratory and was demonstrated to work during several days of testing on DS1 last month. The testing of PEPE on DS1 is another step in preparing NASA for its future of smaller, less expensive missions to explore the solar system. It was turned on again last week, and over the weekend it and a related instrument on another spacecraft observed the solar wind, the stream of charged particles flowing from the Sun. Cassini, an exciting mission to explore the ringed planet Saturn and its environment, carries an instrument that makes measurements similar to the ones PEPE can make. PEPE, with its advanced design, weighs one third and consumes half the power as the instrument on Cassini, but it is nearly as capable. With the two instruments observing the solar wind from different locations, scientists will gain valuable insight into its complex flow through the solar system.

On Sunday night, DS1 participated with the Deep Space Network in a telecommunications experiment. NASA has antennas in Madrid, Spain, near Canberra, Australia, and near Goldstone, California for communicating with probes in deep space, but only certain antennas at Goldstone are capable of receiving the special signals DS1 sent, so the test occurred when the spacecraft was within view of that location on Earth. In December, DS1 validated a very small, lightweight amplifier made by Lockheed-Martin for radio signals at a frequency about 4 times higher than the current standard frequency used for deep-space missions. This frequency band, meaninglessly called Ka-band, is like another channel in the radio spectrum and offers the possibility of sending more information with less power, important for future small but capable spacecraft. Tests conducted on Sunday night are helping the Deep Space Network develop the capability to receive Ka-band routinely for future spacecraft.

Deep Space 1 is almost 45 times as far away as the moon now. At this distance of over 17 million kilometers, or more than 10 million miles, radio signals sent from Earth take nearly a minute to reach the spacecraft; the return signals, of course, take just as long.