Search NASA⌕ Search

SEARCH · Search NASA

Results for “C-BAND”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1969

Low-loss C-band parasitic probe

Low insertion-loss C band parasitic probe couples RF energy from a transmitting medium to a receiving medium with a minimum of interference in order to minimize power requirements.

Cribb, H. E.↗
NASA NTRS1971

Experiment T001: Entry communication on the Gemini 3 mission

Water addition to the Gemini 3 exhaust plasma was studied to determine its effectiveness in the establishment of communication links during the entry portion of the flight. Attenuation levels were measured with and without water injection at uhf frequencies of 230.4 and 296.8 megahertz and at the C-band frequency of 5690 megahertz. Ultrahigh frequency signals that had been blacked out were restored to significant levels, during early portions of the water-injection sequence, by the high flow rate injection. The C-band signal was enhanced by medium and high flow rate injections during the latter portion of the injection period. The uhf signal recovered during water injection resulted in an antenna pattern that was beamed in the radial direction of injection from the spacecraft. Postflight analysis showed that the uhf recovery data were consistent with injection-penetration theory.

Schroeder, L. C.↗
NASA NTRS1971

ATS-5 ranging receiver and L-band experiment. Volume 2: Data reduction and analysis

The results of ranging and position location experiments performed at the NASA Application Technology Satellite ground station at Mojave California are presented. The experiments are simultaneous C-band and L-band ranging to ATS-5, simultaneous C-band and VHF ranging, simultaneous 24-hour ranging and position location using ATS-1, ATS-3, and ATS-5. The data handling and processing technique is also described.

Source record↗
NASA NTRS1974

Comments on Navy/NRL requirements for sea surface temperature and surface wind measurements on Seasat-A

SEASAT instrumentation payload requirements to provide satellite data for the Navy fleet operational fog prediction program include: (1) some form of C-band microwave radiometer capability; (2) a scanning antenna with a 40-km Instanteneous Field of View (IFOV) for the C-band channel; (3) a narrow band and high resolution IR scanning radiometer for cloud free areas; and (4) a capability for measuring surface winds of 3 to 50 m/sec at + or - 10% accuracy and 50 to 100 km spatial resolution.

Ruskin, R. E.↗
NASA NTRS1964

Gemini Program Mission Report for Gemini-Titan 1 (GT-1)

The Gemini-Titan 1 (GT-1) space vehicle was comprised of the Gemini spacecraft and the Gemini launch vehicle. The Gemini launch vehicle is a two-stage modified Titan II ICBM. The major modifications are the addition of a malfunction detection system and a secondary flight controls system. The Gemini spacecraft, designed to carry a crew of two men on earth orbital and rendezvous missions, was unmanned for the flight reported herein (GT-1). There were no complete Gemini flight systems on board; however, the C-band transponder and telemetry transmitters were Gemini flight subsystems. Dummy equipment, having a mass and moment of inertia equal to flight system equipment, was installed in the spacecraft. The Spacecraft was instrumented to obtain data on spacecraft heating, structural loading, vibration, sound pressure levels, and temperature and pressure during the launch phase.

Source record↗
NASA NTRS1966

Postflight Evaluation of Atlas-Centaur AC-6 (Launched August 11, 1965)

The sixth Atlas Centaur vehicle (AC-6) was successfully launched from the Eastern T e s t Range, Complex 36B, on August 11, 1965, at 0931:04.430 EST. A 2084-pound dynamic model of the Surveyor payload was placed in a simulated lunar transfer trajectory. Vehicle systems operated satisfactorily and all the flight objectives were accomplished. Lift-off within 4 seconds of the window opening demonstrated the launch-on-time capability of the vehicle were accurately compensated for by the Centaur guidance system. the Surveyor model into a near-perfect lunar transfer trajectory would have resulted in an impact of the moon without a midcourse correction. To hit the precise target area on the lunar surface, the required correction would have been 4.25 meters per second, which is well within the spacecraft capability. Normal thrust and impulse levels were obtained with both the A t l a s and Centaur propulsion systems. However, a sizeable thrust overshoot on startup of the Centaur engines has not been resolved. A propellant-utilization system used for the first time on the Centaur, accurately controlled the fuel and oxidant consumption. The turnaround and retrothrust maneuver were performed without incident. Relatively high longitudinal modal excitations and lateral payload excitations were obtained at lift-off; these high perturbations are believed t o be related t o the launcher holddown arms. Nominal temperatures were recorded for both the external vehicle skin and the payload compartment; however, abnormally low temperatures were measured in the forward equipment area, which may have resulted from leakage of cold helium purge gas. All vehicle electrical systems performed satisfactorily; the only difficulty with the RF systems was obtained with the C-band transponder. of the vehicle instrumentation yielded valid data. The AC-6 vehicle was constructed with several new lightweight designs including the forward bulkhead, thrust barrel, interstage adapter and tank skin thickness reduction from 0.016 t o 0.014 inch. No deficiencies were observed in any of these new structural elements.

Source record↗
NASA NTRS1970

The variation of radar cross section with wind

X-band (8910 megahertz) and C-band (4455 megahertz) measurements indicate that two domains exist in the variation of radar cross section with wind at incident angles far from the normal. The first domain for flow windspeeds is characterized by a rapid variation of radar cross section with wind and the second domain at higher windspeeds by an asymptotic approach to an upper limit (saturation). The transaction between the two domains occurs at a windspeed of approximately 10 knots. Recent Joint Ocean Surface Study I observations tend to confirm this observation and offer additional proof of the validity of a composite surface model which relates the radar cross section of the sea to the wave-height spectrum. This confirmation was obtained by comparing the radar cross section measured by the four-frequency radar system with the radar cross section calculated from the ocean wave-height spectrum that had been determined by the optical analysis of photographs taken at the same time. A possible explanation for the wind variation of the radar cross section of the open ocean also was evolved, based on radar measurements in a wave tank under various wind conditions and subsequent comparison with optically determined spectra.

Guinard, N. W.↗
NASA NTRS1971

An error analysis of the recovery capability of the relative sea-surface profile over the Puerto Rican trench from multi-station and ship tracking of GEOS-2

Error analyses were performed to examine the height error in a relative sea-surface profile as determined by a combination of land-based multistation C-band radars and optical lasers and one ship-based radar tracking the GEOS 2 satellite. It was shown that two relative profiles can be obtained: one using available south-to-north passes of the satellite and one using available north-to-south type passes. An analysis of multi-station tracking capability determined that only Antigua and Grand Turk radars are required to provide satisfactory orbits for south-to-north type satellite passes, while a combination of Merritt Island, Bermuda, and Wallops radars provide secondary orbits for north-to-south passes. Analysis of ship tracking capabilities shows that high elevation single pass range-only solutions are necessary to give only moderate sensitivity to systematic error effects.

Stanley, H. R.↗