PLANETARY RADAR GROUP
Group 332F

Communications Systems and Research
Section 332

The Radar is part of the Deep Space Network (DSN) and is located at Goldstone in the Mojave Desert some 180 miles north-east of Los Angeles. It is sponsored by the Interplanetary Network Directorate (IND). It operates from the 70 meter antenna DSS-14 at the Mars site at Goldstone. We use the Radar for investigations in planetary astronomy. We support the research of radar astronomers in the Group and in the Space and Earth Sciences Program Directorate (SESPD) at JPL, as well as visiting scientists.

Radar Operation

The principles of Radar operation generally require that we transmit as much power as we can, and the receiver system is as sensitive as we can make it to register the usually faint echo power reflected from the target.

We have two powerful Transmitters on the 70 meter antenna, one developing 400 kW at S-Band (2320 MHz, wavelength 13 cm), and other 500 kW at X-Band (8560 MHz, wavelength 3.5 cm) Today we use X-Band almost exclusively. We have cryogenically cooled Low Noise Amplifiers as the first stage of the Receiver.

In order to confirm that the experiment is proceeding successsfully, we operate with a real-time Data Acquisition System which performs preliminary processing and displays the currently received echo power.

Radar Science

The Radar can observe any accessible Solar System target. We can obtain echoes from Mercury, Venus, Mars, the satellites of Jupiter and Saturn, the Moon, and asteroids and comets. The remaining outer planets, Uranus, Neptune, and Pluto, are too distant to produce a detectable echo at Goldstone with the current equipment.

Near-Earth asteroids, in particular, such as Toutatis and Geographos are prime targets. These are increasingly prominent in scientific interest and concern. Specifically for these we have developed the Single Horn System. This allows fast switching of the radar high power radar for targets which pass close to the Earth.

We use the Radar to investigate the statistics of Orbital Debris. This is material in low-Earth orbit resulting from spacecraft activities and the break-up of satellites and rocket parts. Knowledge about this is crucially important for design of shielding for Space Station modules. The Radar is capable of sensing rice-grained sized particles, which form a large part of the debris.

Most observations take place exclusively at Goldstone, usually at DSS-14 alone, sometimes with DSS-13, the 34-m antenna, as a second receiving site. Other 34-m antennas will be used as they come on-line.
Occasionally we have joint observations with other observing sites; e.g. we also receive radar echoes at the NRAO Very Large Array in the New Mexico desert. We have an active scientific and engineering collaboration with the NAIC Arecibo in Puerto Rico, since this is the only other observatory which does planetary radar. The advantages of sharing common radar data formats and data reduction software with the Arecibo Observatory are obvious.

Overall scientific direction of the Goldstone Radar comes from the Space and Earth Science Programs Directorate (SESPD), which in turn reports to NASA Solar System Exploration Division

Radar Use

In principle anyone with peer-reviewed planetary science funds may propose an experiment which needs the Radar. The applicant presents their proposal for general approval of all users of the DSS14 antenna and the DSN. Approval leads to an application for schedule time, in competition with the other users and their priorities. Generally proposals from outside JPL will have a JPL Radar scientist as a collaborator or at least as an advisor. to guide the process in-house to the actual antenna track time.
There is a User's Guide which advises nomenclature, describes the various Radar observing configurations, and details the other requirements necessary for an observation run or radar track.

Radar Engineering

The engineering direction of the Radar develops principally from the scientific requirements established by the Space and Earth Science Programs Directorate (SESPD). We formulate implementation efforts within JPL Division 33, working very closely with TMOD 940 Office DSN Data Systems which has overall responsibility for DSN Implementation Engineering.

Many of the features in the Radar are unique in the DSN and also in the world. The successful operation of the world's most powerful X-Band continuous wave (CW) transmitters in particular requires dedicated and extensive expertise. The GSSR still aims to develop and integrate new technologies such as the all-digital JPL Block V Receiver, to improve the science return and operational reliability.

It is our purpose to increase productivity of antenna use, to get more and better images per transmitted photon per transmitter second.

N A S A - The National Aeronautics and Space Administration

N A S A - Near Earth Objects Report

See Near-Earth Object Program or go directly to Near-Earth Object Surveys and Hazard Mitigation Strategies: Final Report from January 2010