Issue 10 Volume 41 May 16, 2003

Jason-1, launched on December 7, 2001, is continuing the time series of centimeter level ocean topography observations
as the follow-on to the highly successful TOPEX/POSEIDON (T/P) radar altimeter satellite. The precision orbit determination
(POD) is a critical component to meeting the ocean topography goals of the mission. T/P has demonstrated that the time
variation of ocean topography can be determined with an accuracy of a few centimeters, thanks to the availability of highly
accurate orbits based primarily on SLR+DORIS tracking. The Jason-1 mission is intended to continue measurement of the
ocean surface with the same, if not better accuracy. Fortunately, Jason-1 POD can rely on four independent tracking data types
available including near continuous tracking data from the dual frequency codeless BlackJack GPS receiver. Orbit solutions
computed using individual and various combinations of GPS, SLR, DORIS and altimeter crossover data types have been
determined from over 100 days of Jason-1 tracking data. The performance of the orbit solutions and tracking data has been
evaluated. Orbit solution evaluation and comparison has provided insight into possible areas of refinement. Several aspects
of the POD process are examined to obtain orbit improvements including measurement modeling, force modeling and solution
strategy. The results of these analyses will be presented.
Author
Satellite Altimetry; Orbit Determination; Satellite Tracking; Global Positioning System; Satellite Orbits; Data Processing
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SPACECRAFT INSTRUMENTATION AND ASTRIONICS
Includes the design, manufacture, or use of devices for the purpose of measuring, detecting, controlling, computing, recording, or
processing data related to the operation of space vehicles or platforms. For related information see also 06 Avionics and Aircraft
Instrumentation; for spaceborne instruments not integral to the vehicle itself see 35 Instrumentation and Photography; for spaceborne
telescopes and other astronomical instruments see 89 Astronomy.
20030036992 NASA Goddard Space Flight Center, Greenbelt, MD, USA
GEOSAT Follow-on (GFO) Altimeter Document Series, Volume 3, GFO Altimeter Engineering Assessment Report,
Version 1
Hancock, David W., III; Hayne, George S.; Brooks, Ronald E.; Lockwood, Dennis W.; March 2002; 73 pp.; In English;
Original contains black and white illustrations
Contract(s)/Grant(s): RTOP 622-47-36-02
Report No.(s): NASA/TM-2002-209984/VER1/VOL3; NAS 1.15:209984/VER1/VOL3; Rept-2002-01549-0; No Copyright;
Avail: CASI; A04, Hardcopy
The U.S. Navy’s Geosat Follow-On (GFO) Mission, launched on February 20, 1998, is one of a series of altimetric
satellites which include Seasat, Geosat, ERS-1, and TOPEX/POSEIDON (T/P). The purpose of this report is to document the
GFO altimeter performance determined from the analyses and results performed by NASA’s GSFC and Wallops altimeter,
calibration team. It is the second of an anticipated series of NASA’s GSFC and Wallops GFO performance documents, each
of which will update assessment results. This report covers the performance from instrument acceptance by the Navy on
November 29, 2000, to the end of Cycle 20 on November 21, 2001. Data derived from GFO will lead to improvements in the
knowledge of ocean circulation, ice sheet topography, and climate change. In order to capture the maximum amount of
information from the GFO data, accurate altimeter calibrations are required for the civilian data set which NOAA will produce.
Wallops Flight Facility has provided similar products for the Geosat and T/P missions and is doing the same for GFO.
Author
Altimeters; Geosat Satellites; Topography; Ocean Surface; Satellite Instruments; Satellite Altimetry; Satellite-Borne Radar
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SPACECRAFT PROPULSION AND POWER
Includes main propulsion systems and components, e.g., rocket engines; and spacecraft auxiliary power sources. For related
information see also 07 Aircraft Propulsion and Power, 28 Propellants and Fuels, 15 Launch Vehicles and Launch Operations, and 44
Energy Production and Conversion.
20030032338 NASA Glenn Research Center, Cleveland, OH, USA
High-Performance, Space-Storable, Bi-Propellant Program Status
Schneider, Steven J.; [2002]; 14 pp.; In English; Propulsion Engineering Research Center 14th Annual Symposium on
Propulsion, 10-11 Dec. 2002, PA, USA; Original contains black and white illustrations; No Copyright; Avail: CASI; A03,
Hardcopy
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