Engineering topics

Hockensmith, R. P.

Publications and source records attributed to Hockensmith, R. P..

4 records

NASA NTRS1984

Electronic Switching Spherical Array (ESSA) antenna systems

ESSA (Electronic Switching Spherical Array) is an antenna system conceived, developed and qualified for linking satellite data transmissions with NASA's tracking and data relay satellites (TDRSS) and tracking and data acquisition satellites (TDAS). ESSA functions in the S band frequency region, cover 2 pi or more steradians with directional gain and operates in multiple selectable modes. ESSA operates in concert with the NASA's TDRS standard transponder in the retrodirective mode or independently in directional beam, program track and special modes. Organizations and projects to the ESSA applications for NASA's space use are introduced. Coverage gain, weight power and implementation and other performance information for satisfying a wide range of data rate requirements are included.

Hockensmith, R. P.↗

NASA NTRS1983

The electronic switching spherical array antenna for the Earth Radiation Budget Spacecraft

The ESSA is a microprocessor-controlled antenna for low orbiting spacecraft for telemetry and command relay through the Tracking and Data Relay Satellite System (TDRSS). The array is a hemispherical shape covered with disk radiating elements. A group of radiating elements are continuously selected by the microprocessor controller to form a beam in the direction of a TDRS. A radial switching power divider uses PIN diodes to select the desired radiating elements. The antenna gain is a function of the size of the hemispherical dome. A 30-inch diameter dome is presently being built for the Earth Radiation Budget Spacecraft (ERBS). Gain of this antenna over a hemisphere is 14 dBi and polarization is lefthand circular. There are 145 radiating elements with 12 being used at one time to form a beam. The ESSA subsystem weights 74 pounds and power consumption is 20 watts. RF power handling capability is 30 watts. The S-Band radiating elements have a 10 percent bandwidth that allows simultaneous transmission and reception.

Kudrna, K.↗

NASA NTRS1977

A GSTDN/TDRSS compatible RF system for the Solar Maximum Mission /SMM/

The Solar Maximum Mission (SMM) is a major NASA observatory to be launched in late 1979. SMM will be supported by NASA's existing Ground Spaceflight Tracking and Data Network (GSTDN) and the planned Tracking and Data Relay Satellite System (TDRSS). Design of a GSTDN/TDRSS compatible RF system for SMM poses multiple problems related to the complex nature of the observatory command, telemetry, and tracking support requirements and the fundamental differences in signal design, antenna characteristics, data rates, and link performance criteria for GSTDN vs. TDRSS support. The RF system described in this paper achieves full compatibility with a minimum of hardware complexity by use of an integrated antenna system, the NASA standard S-Band transponder, and utilization of both the single access and multiple access support capabilities of the TDRSS to handle both real time data and tape recorder dumps.

Heffernan, P. J.↗

NASA NTRS1977

The ESSA solution

ESSA (Electronic Switching Spherical Array) is a fixed truncated spherical antenna with its elements over the complete surface, conceived to satisfy many future antenna system requirements. Constant gain and beam shape throughout large volumetric coverage regions are the principle characteristics. In the present paper, the two existing types of ESSA are discussed. ESSA I is a simple nonphase correcting aperture approach characterized by light weight, low dc power consumption, gain between +7 and +14 dB, and 90% spherical coverage. ESSA II is a phase corrected aperture which would have very low sidelobe levels and improved gain over ESSA I (12 to 22 dB), but would be heavier and require more dc power.

Hockensmith, R. P.↗