Dr. Karl Erb, the Director, Office of Polar Programs (OPP), discussed the important relationship between the construction of the new South Pole Station and NSF/OPPs planning support of communications for the new station. The goal of this workshop is to define communications requirements and options to support these requirements (short- and long-term) so that the capability exists to support the science through the completion of the new South Pole Station in 2005.
Mr. Patrick Smith, Technology Development Manager, OPP, led a presentation and discussion of current satellite communication capabilities at all of the USAP Antarctic stations.
At McMurdo Station, commercial satellite communication service, a full period (24 hrs/day) T1 communications circuit (1.544 Mb/s), is provided by SPAWAR Systems Center, Charleston, SC, through a contract to AT&T/ALASCOM until Feb. 2000. Continuity of service is of prime concern and SPAWAR plans to re-compete the service contract, with award planned by 1 Oct. 1999. It is estimated that the bandwidth may be able to double without increase in cost. The time division multiplexed (TDM) fractional T1 service provided includes telephone, fax, Internet, and private data network links (Table 1).
McMurdo Station-based scientists find the satellite communications provided comparable to any institution, although they are presently not moving large files (image or data) like South Pole astronomers and physicists. Scientists working on the Long Term Ecological Research (LTER) Project, based in the nearby McMurdo Dry Valleys, however, have increasing requirements for Internet access for e-mail and data file transfer, which has only recently been provided in a limited fashion.
Table 1: McMurdo Station Satellite Communications
|TDM Fractional Services|
|Business Telephone||Public Telephone||Facsimile||ISDN Access||Internet||Other Circuits|
|8||10||5 (2 In/3 Out)||2 Switched 56 Lines (64 kb/s each)||684 kb/s||
128 kb/s private NASA
9.6 kb/s private USAF/AFTAC
At Palmer Station, satellite communication service for part of the day is provided by three satellites presently (ATS-3, LES-9, and INMARSAT). Palmer Station has excellent visibility to many international satellites in the geosynchronous arc servicing North and South America and Europe. Future plans call for the installation of 24 hour a day coverage by one of the international satellite operators (e.g., Intelsat or Hughes/Panamsat) (Table 2).
Table 2: Palmer Station Inventory of Present/Future Satellite Capability
|Present Satellites||Future Satellites|
|System Parameter||ATS-3||LES-9||INMARSAT||INTERNATIONAL FIXED SATELLITE SERVICE|
|Contact Time Per Day||2 Hours Minimum||4-6 Hours||Available 24 Hours||24 Hours|
|Link Rate||1.2-2.4 KB/s||38 KB/s||64 KB/s High Speed Data Available||256 KB/s Initially, Scaleable to T1|
|Link Direction||Half-Duplex||Full Duplex||Full Duplex||Full Duplex|
|Link Quality||Poor-Fair: Variable due to Ionosphere||Fair-Good: Variable due to Ionosphere||Excellent||Excellent|
At South Pole Station, approximately 13 hr/day of connectivity exist using four satellites, ATS-3, LES-9, GOES-3, and TDRS F1 (Table 3). South Pole has a theoretical daily total throughput of 5,180 MBytes/day with all existing satellite resources and 656 MB/d without any TDRS F1 service. This estimate does not include a realistic derating of throughput based on such factors as TCP/IP Internet protocol overhead, data transmission session overhead, link fade periods, link error rates, etc. This estimate must be considered an optimal upper bound of throughput. Any practical systems implemented will perform at lower levels of performance. Loss of TDRS F1 would have a catastrophic effect on scientific research being conducted at South Pole Station. An Iridium handset was successfully tested at South Pole Station for voice (only) during the 1998-99 season as a part of the Iridium Beta Test Program.
Table 3: South Pole Station Inventory of Present Satellite Capability
|System Parameter||ATS-3||LES-9||GOES-3||TDRS F1 SSA F/R||TDRS F1 KSAR|
|Service||Orderwire Voice Public Telephone Network||Internet||Internet; Voice-over-IP telephone||Internet; Voice-over-IP telephone||High Speed Store & Forward Data Flow|
|Contact Time Per Day||7 Hours||6.5 Hours||6 Hours||4 Hours||4 Hours|
|Link Rate||1.2-2.4 kb/s||38 kb/s||256 kb/s (1544 kb/s by FY05)||1024 kb/s||2000 kb/s|
|Link Direction||Half Duplex||Full Duplex||Full Duplex||Full Duplex||Simplex|
|Link Quality||Poor-Fair: Variable due to Ionosphere||Poor-Fair: Variable due to Ionosphere||Excellent||Excellent||Excellent|
|Comments/ Future of Satellite||NASA funding for operations ends in FY99; to be decommissioned in FY00 due to Iridium||Negotiation with USAF for continued access successful; NSF contributing to support in FY99 and will totally fund support by FY01||Antenna controller improvements by ASA FY99; MOA with NOAA to be signed off soon in FY99; negotiation with University of Miami for contract support of T&C and services||10 February 1999 NASA agreed to keep operational to support NSF; MOA is to be established; NSF to begin contribution to support in FY99; NASA to build a dedicated ground terminal at White Sands; satellite health a significant issue; MPEG-2 digital video (6 MB/s) test sent successfully from South Pole; NASA/GSFC/Code 450 working on short term SPTR upgrade|