U.S./Foreign Military and Other U.S. Government Satellite Resources

Mr. Phil Sobolewski, SPAWAR Charleston, presented and led a discussion on potential U.S./foreign military and other U.S. government satellite resources to meet South Pole Station communication requirements. Over forty satellites were examined by SPAWAR for present and future capabilities and are summarized in Table 9.

Satellite bandwidth capability varied from Milstar and EHF Polar (0.000075 MHz) to DSCS (85 MHz). Geo orbit satellite inclinations ranged from UFO-7 (4 degrees) to FLTSAT-1 (13.8 degrees). South Pole daily visibility was a minimum with FLTSAT-4 (6.5 hrs) to a maximum with GPS 2A-13 (9.5 hrs). South Pole/CONUS Mutual Daily Visibility varied from GPS 2A-13 (3 hrs) to FLTSAT-4 (5.5 hrs). Daily theoretical data transfer capability ranged from a minimum with FLTSAT-4 (9.9 GB/d) to a maximum with GPS 2A-13 (12 GB/d).

SPAWAR concluded that the current possibilities are the FLTSAT F1 and F4, GPS NAVSTAR 2A-13, and NRO satellites, and future possibilities are, Advanced EHF Polar Follow-On System, and DSCS-3 F1 and NATO III-D following replacement (see Table 9 for details).

SPAWAR recommends that NSF/OPP consider taking these next steps:

1. Pursue authorization to use FLTSAT F1 or F4, and GPS NAVSTAR 2A-13.
2. Pursue the NRO geosynchronous satellite possibility.
3. Research the ground equipment requirements for current and future communication scenarios.
4. Prepare for future possibilities.
5. Execute the down selection process.

Presentation and Discussion of Possible Options

Mr. Erick Chiang, NSF/OPP Section Head, Polar Research Support Section, led the participants in a review discussion of possible options and detailing summary recommendations. NSF/OPP is transitioning from an ad hoc process to a systematic approach to addressing communications, which is learning a different mode of doing business at South Pole.

The following questions were presented for clarification by the participants of the workshop:

1. Is there anything more to add regarding bandwidth?
2. How reliable should communication systems be?
3. What should the degree of connectivity be?
4. What are the short-term (FY02)/long-term (beyond FY02) options?
5. What should the strategy be for implementation with risk mitigation — backups?
6. What are the costs and benefits of the various communication options?
7. What should be the short-term allocation of resources?

The recommended availability, reliability, and bandwidth for communication systems at South Pole Station were defined (Table 10).

A 99% availability translates into an annual acceptable total outage of 87.6 hours per year (based on continuous 24 hour/day coverage), or equivalently 7.3 hours per month or 14.4 minutes/day. In the case of the Internet, outage would have to be defined as the service not being available due to whatever causes, to include performance degrading below some pre-defined acceptable level (a present issue with the service provided via LES-9 - the link is highly available when the satellite is visible, but link quality is often marginal, meaning that many kinds of applications cannot be performed over the Internet link).

Short-term (FY02)/long-term (beyond FY02) options were identified and three categories of capability recommended: minimum, acceptable, and wish list. To meet short-term communication requirements, while the long-term options are being identified, the following primary satellites are recommended to be maintained with backup satellites:

1. current mix of satellites
   1. GOES-3
   2. TDRS F1
   3. Iridium
   4. LES-9
2. backup satellites
   1. MARISAT
   2. GOES-2
   3. Military alternatives

Last, it was recommended that NSF/OPP consider installation of a flexible ground station to take advantage of the various satellite systems presently available and potentially available in the future.

The workshop concluded with nine summary conclusions being made to NSF/OPP for review and action (see Executive Summary and Summary Conclusions).

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