Continuity of NOAA Satellites (1997) / Chapter Skim
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CHAPTER 4: ENSURING CONTINUITY
CHAPTER 4: ENSURING CONTINUITY
Pages 27-40
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From page 27... ...
PAST PERFORMANCE OF GEOSTATIONARY OPERATIONAL ENVIRONMENTAL SATELLITES AND POLAR-ORBITING OPERATIONAL ENVIRONMENTAL SATELLITES The operational experience for GOES over about two decades is summarized in Table 4-1. Useful life of the U.S.-launched geostationary satellites ranges from iThe Monte Carlo model operates using random numbers to select the probability of events occurring in a large number of simulated scenarios.
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From page 29... ...
These computations do not include the ITOS series of six satellites, which bear little resemblance to the current satellite or instrument designs. PREDICTIONS OF FUTURE PERFORMANCE NASA commissioned engineering studies to evaluate the probabilities of GOES and POES continuity as the POES program makes the transition to the 2Useful life is the length of time a satellite actually performed its mission.
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From page 30... ...
2/87; a second failed 5/87; these failures significantly degraded soundings. hNOAA-ll AVHRR and HIRS degraded from 10/89 due to orbit drift that caused sunlight to periodically enter instrument apertures.
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From page 31... ...
· Launch vehicle reliability was assumed to be 90 percent, the industry average at that time. This operating scenario projected ten GOES launches from 1994 through 2009, with six failures during that time, ending with two operational satellites and two backup satellites in orbit (see related discussion on pp.
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From page 32... ...
These models may be used to indicate behavior and approximate levels of availability of the POES and GOES satellites. Sensivity studies in the referenced reports showed the system to be fairly insensitive to variations in parameters, such as satellite reliability and lifetime (due to expendables)
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From page 33... ...
SCHEDULE OF FUTURE GEOSTATIONARY OPERATIONAL ENVIRONMENTAL SATELLITES AND POLAR-ORBITING OPERATIONAL ENVIRONMENTAL SATELLITES The planned launch schedule for GOES is shown in Table 4-3. The actual schedule will depend primarily on the need for replacement satellites, of course, but also on spacecraft and launch availability.
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From page 34... ...
The launch schedule for NOAA-M is based on successful conclusion of the European agreement. In May 1994, President Clinton signed a presidential decision directive to merge the POES system and the DMSP into a single system to "reduce the cost of acquiring and operating polar-orbiting environmental satellite systems, while continuing to satisfy U.S.
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From page 35... ...
When considering ways to develop new spacecraft and incorporate major new improvements in technology, NOAA should carefully consider the lead times dictated by the required launch schedules and the very long procurement cycle. NOAA should develop schedules for the transition from current designs to new ones, such as NPOESS and GOES-A, that adequately account for the necessary lead times for funding approval, procurement, design and development, fabrication, and verification.
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From page 36... ...
(See findings and recommendations 3 and 4.) GEOSTATIONARY OPERATIONAL ENVIRONMENTAL SATELLITE GROUND FACILITIES AND BACKUP SYSTEMS The operations ground equipment for GOES consists of components located at the CDA station near Wallops Island, Virginia, and the SOCC at Suitland,
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From page 37... ...
GEOSTATIONARY OPERATIONAL ENVIRONMENTAL SATELLITE BACKUP From 1993 to 1995, when only one GOES spacecraft was operational, EUMETSAT loaned NOAA a geostationary weather satellite, METEOSAT-3. The satellite was repositioned to 75 degrees west longitude in order to cover the eastern United States and Atlantic Ocean (see Table 4-1~.
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From page 38... ...
coverage, it would be moved if an operational GOES fails, if no other operable GOES is in orbit, if a GOES launch is not possible within four months, and if at least two operable METEOSATs are in orbit. If EUMETSAT makes the same request for a GOES to be moved to ensure European coverage, but not farther east than 5 degrees west longitude, it would be moved only if the operational METEOSAT fails, if there is no other operable METEOSAT in orbit, if a METEOSAT launch is not possible within four months, and if at least two operable GOES are in orbit.
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From page 39... ...
SATELLITE LAUNCHES As discussed earlier in this chapter and in Chapter 3, the NOAA mission requires at least two operational geostationary satellites in orbit at all times. At least one operational polar-orbiting satellite and an additional backup satellite in orbit are needed at all times to ensure continuous service.
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From page 40... ...
The planned GOES, POES, METOP, and NPOESS procurements are adequate to provide continuity of the NOAA geostationary and polar-orbiting satellites for at least the next 15 years, if they are funded and carried out on the current schedule. Recommendation 8.
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