Radar Studies of the Moon
Radar studies of moon - theory of thermal emission, radiometric data analysis, input ephemeris accuracy, output mapping display, and progress on 8-mm radar system
LUNAR MAP↗
SEARCH · Search NASA
Results for “EPHEMERIS”
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.
Systems analysis research
Shadow equation for satellite, consistent ephemeris of major planets in solar system, correction process for lunar orbit, and numerical approximation of Hermite expansion
Source record↗
Gravitational inconsistency in the lunar theory - Confirmation by radio tracking.
Residuals in lunar ephemeris calculated from Brown theory confirmed by lunar probes radio tracking and reduced by repeated calculations, using LE 5
Cary, C. N.↗
ABTRAJ on-site tracking prediction program
Computer program, ABTRAJ, provides Deep Space Network tracking stations with the capability of generating spacecraft predictions with on-site computers. The program is comprised of two major sections - the main prediction portion and a trajectory subroutine which spans the desired predict interval with spacecraft ephemeris data written on magnetic tapes.
Berman, A. L.↗
Systems Division
Solar electric propulsion system for spacecraft asteroid probe, numerical integration calculation of lunar ephemeris, and effect of precession and nutation errors on radar observations
Source record↗
An Encke-type special perturbation method.
Encke type analytical-numerical integration for solving differential equations of modified set of Lagrange planetary equations, obtaining satellite ephemeris for orbit prediction
Born, G. H.↗
Laser beam directed at the lunar retro- reflector array - Observations of the first returns.
Lunar laser beam retroreflection observations, showing agreement with predicted ephemeris and signal strength
Carrion, W.↗
Determination of astrodynamic constants and a test of the general relativistic time delay with S-band range and Doppler data from Mariners 6 and 7
Earth/moon mass ratio and Mars mass and ephemeris from Mariners range and Doppler tracking data, noting relativistic time delay measurement possibility
Anderson, J. D.↗
Celestial mechanics experiment for Mariner Mars 1971
Celestial mechanics experiment for Mariner Mars 1971 to test general relativity theory and improve Martian ephemeris
Anderson, J. D.↗
A preliminary special perturbation theory for the lunar motion
Lunar ephemeris for nanosecond resolution laser ranging systems by literal and numerical integration techniques
Garthwaite, K.↗
Determination of astrodynamic constants and a test of general relativistic time delay with S-band range and Doppler data from Mariners 6 and 7
General relativistic time delay and moon-earth masses and Mars mass-ephemeris ratios from S-band range and Doppler tracking
Anderson, J. D.↗
Information content of the Mariner Mars 1971 radio tracking data
Covariance analysis of Mars gravity harmonics, ephemeris and radiation pressure from Mariner 1971 range and Doppler radio tracking data
Lorell, J.↗
Minicomputer-controlled programmed oscillator
Two programmed oscillators have been constructed, each using a low-cost minicomputer for the calculation and control functions, and each contained in a single rack of equipment. They are capable of operation in a phase-tracking mode as well as a frequency-tracking mode. When given an ephemeris suitable for the planet Venus, these units maintained phase coherence of better than 5 deg rms at 2388 MHz.
Winkelstein, R.↗
Anchoring spacecraft to planets
For planet tracking, the immense mass relative to applied nongravitational forces (for even the smaller asteroids) removes limitations on the ability to model orbital motion mathematically. A lander on a natural satellite (other than the moon) would not suffer from nongravitational effects, and would further have a large mean motion, which is important for observing gravitational effects. The tracking of a Mars lander over a long period would yield conclusions in the areas of relativity (determination of the parameter beta), the inertial framework, Mars' internal structure (based on the polar moment), and Mars' physical ephemeris.
Cain, D. L.↗
Guidance and Navigation Requirements for Unmanned Flyby and Swingby Missions to the Outer Planets: Low Thrust Missions, Phase B - Volume 3
The guidance and navigation requirements for unmanned missions to the outer planets, assuming constant, low thrust, ion propulsion are discussed. The navigational capability of the ground based Deep Space Network is compared to the improvements in navigational capability brought about by the addition of guidance and navigation related onboard sensors. Relevant onboard sensors include: (1) the optical onboard navigation sensor, (2) the attitude reference sensors, and (3) highly sensitive accelerometers. The totally ground based, and the combination ground based and onboard sensor systems are compared by means of the estimated errors in target planet ephemeris, and the spacecraft position with respect to the planet.
Source record↗
Study of a comet rendezvous mission. Volume 2: Appendices
Appendices to the comet Encke rendezvous mission consider relative positions of comet, earth and sun; viewing condition for Encke; detection of Taurid meteor streams; ephemeris of comet Encke; microwave and optical techniques in rendezvous mission; approach instruments; electrostatic equilibrium of ion engine spacecraft; comet flyby data for rendezvous spacecraft assembly; observations of P/Encke extracted from a compilation; and summary of technical innovations.
Source record↗
Mars gravitational field estimation error
The error covariance matrices associated with a weighted least-squares differential correction process have been analyzed for accuracy in determining the gravitational coefficients through degree and order five in the Mars gravitational potential junction. The results are presented in terms of standard deviations for the assumed estimated parameters. The covariance matrices were calculated by assuming Doppler tracking data from a Mars orbiter, a priori statistics for the estimated parameters, and model error uncertainties for tracking-station locations, the Mars ephemeris, the astronomical unit, the Mars gravitational constant (G sub M), and the gravitational coefficients of degrees six and seven. Model errors were treated by using the concept of consider parameters.
Compton, H. R.↗