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Peng, C. Y.

Publications and source records attributed to Peng, C. Y..

10 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1998

Mars Pathfinder Atmospheric Entry Reconstruction

The primary objective of the Mars Pathfinder mission was to demonstrate an innovative, low-cost and reliable method for placing a science payload on the surface of Mars. This paper describes the results of an effort to access the spacecraft performance during Entry, Descent and Landing.

Mars↗
NASA NTRS1997

Test/Model Correlation for Mars Pathfinder Multi-Body System Drop Tests

A multi-body dynamics computer model was used extensively for the Mars Pathfinder mission to simulate its innovative and uncoventional atmospheric entry, descent and landing approach. To verify the accuracy and validity of this model was vital to the success of this mission, two multi-body system drop tests were performed and augmented by an extensive model correlation effort.

Mars↗
NASA NTRS1997

Modal Test of the Cassini Spacecraft

Modal testing of the Cassini spacecraft posed a challenge due to the large size and dynamic complexity of the spacecraft...This paper presents an overview of the test methods and results, with an emphasis on lessons learned.

modal↗
NASA NTRS1997

Model Correlation for Mars Pathfinder Entry, Descent and Landing Simulation

Two multi-body drop tests were conducted to provide data to calibrate and verify a multi-body dynamics computer model, which was the major analytical tool used to study the entry, descent and landing (EDL) of the Mars Pathfinder mission. A general summary of the tests and important features of the simulation model are presented in this paper. Good correlation between between test results and analytical predictions were achieved.

Mars↗
NASA NTRS1992

Sea surface mean square slope from Ku-band backscatter data

A surface mean-square-slope parameter analysis is conducted for 14-GHz airborne radar altimeter near-nadir, quasi-specular backscatter data, which in raw form obtained by least-squares fitting of an optical scattering model to the return waveform show an approximately linear dependence over the 7-15 m/sec wind speed range. Slope data are used to draw inferences on the structure of the high-wavenumber portion of the spectrum. A directionally-integrated model height spectrum that encompasses wind speed-dependent k exp -5/2 and classical Phillips k exp -3 power laws subranges in the range of gravity waves is supported by the data.

Jackson, F. C.↗
NASA NTRS1985

A comparison of in situ and airborne radar observations of ocean wave directionality

The directional spectrum of a fully arisen, about 3 m sea as measured by an experimental airborne radar, the NASA K(u)-band radar ocean wave spectrometer (ROWS), is compared to reference pitch-roll buoy data and to the classical SWOP (stereo wave observations project) spectrum for fully developed conditions. The ROWS spectrum, inferred indirectly from backscattered power measurements at 5-km altitude, is shown to be in excellent agreement with the buoy spectrum. Specifically, excellent agreement is found between the two nondirectional height spectra, and mean wave directions and directional spreads as functions of frequency. A comparison of the ROWS and SWOP spectra shows the two spectra to be very similar, in detailed shape as well as in terms of the gross spreading characteristics. Both spectra are seen to exhibit bimodal structures which accord with the Phillips' (1958) resonance mechanism. This observation is thus seen to support Phillips' contention that the SWOP modes were indeed resonance modes, not statistical artifacts.

Jackson, F. C.↗
NASA NTRS1985

ROWS estimates of wave height, wind speed, and directional wave spectra for SIR-B underflights off Chile, October 11 and 12, 1984

An account is given of the successful operation of the Goddard Ku-band Radar Ocean Wave Spectrometer (ROWS) on four out of five of the NASA Wallops' P-3 underflights of the Shuttle Imaging Radar-B (SIR-B) off the coast of southern Chile during the period of October 7-12, 1984. ROWS provided surface wind speed, wave height, and directional wave height spectrum estimates from the instrument's nadir altimeter mode and off-nadir spectrometer mode. ROWS estimates of the directional spectra of 300-400-m wavelength swell-dominated 3-5 m seas on October 11 and 12 are presented and compared to SCR (Surface Contour Radar), SIR-B, and Navy GSOWM spectra. Good agreement is found with SCR height spectra for the 12th (when the SCR was operable). Also, surprisingly good agreement is found between ROWS slope spectra and SIR-B image spectra for both the 11th and 12th for both swell and local wind-sea components. ROWS altimeter mode estimates of maximum winds of about 10 m/s on the 11th and 12th are seen to be consistent with the ROWS spectrometer mode observed local wind-sea peak frequencies of about 0.12-0.14 Hz.

Jackson, F. C.↗