DEEP SPACE INSTRUMENTATION FACILITY
The National Aeronautics and Space Administration has constructed a network of deep-space tracking stations for lunar and planetary exploration missions. In order to provide continuous, 24-hour coverage, three stations were built, approximately 120 degrees of longitude apart, around the world: at Goldstone in the California desert, near Johannesburg in South Africa, and at Woomera in the south-central Australian desert.
The three tracking stations of the Deep Space Instrumentation Facility are located around the world so as to provide continuous flight coverage.
These stations are the basic elements of the Deep Space Instrumentation Facility (DSIF). In addition, a mobile tracking station installed in vans is used near the point of injection of a spacecraft into an Earth-escape trajectory to assist the permanent stations in finding the spacecraft and to acquire tracking data. The control point for the DSIF net is located at JPL in Pasadena, California (see [Table 1]).
The Jet Propulsion Laboratory has the responsibility for the technical direction of the entire DSIF net and operates the Goldstone facilities with assistance from the Bendix Corporation as a subcontractor. The overseas stations are staffed and operated by agencies of the Republic of South Africa and the Commonwealth of Australia.
The DSIF net tracks the position and velocity of U.S. deep-space probes, issues commands to direct the spacecraft in flight, receives engineering and scientific data from the probes, and automatically relays the data to JPL in Pasadena, where it is processed by computers and interpreted. (In the tracking operation, a signal is transmitted to the spacecraft, where it is received and processed in a transponder, which then sends the signal back to the Earth. The change in frequency, known as the doppler effect, involved in this operation enables engineers to determine the velocity at which the spacecraft is moving.)
Table 1. Deep Space Instrumentation Facility Stations
| Station | Location | Equipment | Functions | |
|---|---|---|---|---|
| DSIF 1 (Mobile Tracking Station) | Near point of injection of spacecraft into Earth-escape trajectory | 10-ft antenna 25-w, 890-mc transmitter | Fast tracking for acquisition of spacecraft | |
| Goldstone: | California | |||
| Pioneer Site (DSIF 2) | 85-ft polar-mount antenna; Cassegrain feed; maser and parametric amplifier | Reception of telemetry Tracking spacecraft | ||
| Echo Site (DSIF 3) | 85-ft polar-mount antenna; parametric amplifier 10-kw, 890-mc transmitter | Transmission of commands Tracking spacecraft Stand-by reception | ||
| Venus Site | 85-ft radar-type antenna | Advanced radar astronomy Communications research | ||
| DSIF 4 | Woomera, Australia | 85-ft polar-mount antenna; parametric amplifier | Reception of telemetry Tracking spacecraft | |
| DSIF 5 | Johannesburg, South Africa | 85-ft polar-mount antenna; parametric amplifier 10-kw, 890-mc transmitter | Reception of telemetry Tracking spacecraft Transmission of commands |
The stations are equipped with receiving and tracking instruments so sensitive that engineers estimate that they can detect radio-frequency energy equivalent to that radiated by a 1-watt light bulb at a distance of approximately 75 to 80 million miles. Such energy received at the antenna would measure about 0.00000000000000000002 watt (2 × 10⁻²⁰).
The amount of power received at the antenna during Mariner’s encounter with Venus has been calculated at about 0.000000000000000001 of a watt (1 × 10⁻¹⁸). If a 100 percent efficient storage battery were charged with this amount of energy for some 30 billion years, the battery would then have stored enough energy to light an ordinary 1-watt flashlight bulb for about 1 second only.
Furthermore, Goldstone engineers estimate that, if Mariner II had continued to function in all its systems and to point its directional antenna at the Earth, useful telemetry data could have been obtained by the DSIF stations out to about 150 to 200 million miles, and tracking data could have been secured from as far as 300 to 400 million miles.
Construction of the DSIF net was begun in 1958. The Goldstone station was ready for the Pioneer III mission in December of that year. In March, 1959, Pioneer IV was successfully tracked beyond the Moon. Later in 1959, Pioneer V was tracked out to over 3 million miles.
Goldstone participated in the 1960 Project Echo communication satellite experiments and the entire net was used in the Ranger lunar missions of 1961-1962. The Goldstone station performed Venus radar experiments in 1961 and 1962 to determine the astronomical unit more precisely and to study the rotation rate and surface characteristics of the planet.
Following the launch of Mariner II on August 27, 1962, the full DSIF net provided 24-hour-per-day tracking coverage throughout the mission except for a few days during the cruise phase. The net remained on the full-coverage schedule through the period of Venus encounter on December 14.