1. Data Communications Supporting Astronomy/Astrophysics at South Pole Station Erick Chiang, NSF-OPP NASA-NSF Astronomy/Astrophysics Advisory Committee May 11, 2006 Arlington, VA

2. Contiguous Coverage: 11.5 hrs/day Max. Bulk File Xfer: ~ 10 GB/day Bulk File Xfer: TDRS F1 only TCP/IP networks: all satellites GOES-3 TDRS F1 MARISAT-2 Current Service Equator

3. Demand & Capacity Forecast Baseline: TDRS @ 5 Mb/s Upgrade #1: TDRS @ 45 Mb/s Upgrade #2: TDRS @ 150 Mb/s GBytes/Day

4. Space Segment Planning Issues TDRS F1 –Provides best value – flat fee (~$650K/yr) for NSF dedicated use of complete daily viewing window –End of life likely during 2007-2008 forces a switch to TDRS F3 TDRS F3 –NSF as a fully scheduled user, subject to NASA priorities and $130/min fee –User fees disincentive for NSF to maximize IP network service – service model restricts air-time to ~ 90 min/day to move bulk data @ 150 Mb/s Other Satellites –MARISAT-2 end of life estimated for August, 2010 –GOES-3 service variable and at-risk due to satellite age Impacts –Broadband IP network daily connectivity and quality will decline significantly –Recurring operations cost will rise sharply Non-NASA options under study, but results are not encouraging

5. NSF Long Range Plan Action Upgrade existing SPole & White Sands earth stations @ $1.5M Expand Iridium Multiplex service @ $300K MARISAT-2 as TDRS contingency Construct New SPole earth station @ $6.5M Continue search for satellites Result 2007: 45 Mb/s TDRS F1 link @ 75 GB/day (max) 2007: 24 kb/s thin IP network gapfiller link 2007: 4 Mb/s back-up link 2009: 150 Mb/s TDRS F3 link @ 250 GB/day (max) Additional First Generation operational TDRS in view in 2006, 2007, 2008, & 2009 Other future options remain elusive

6. NASA Long Range Planning First Generation fleet (F1-F7) will age and incrementally fail NSF will face increased competition for dwindling first generation fleet NASA VSE roadmaps for space communications/navigation nearing/at completion Roadmaps stated need for 2 additional Second Generation (F8-F10) satellites by 2015 to meet demand Second Generation satellite orbits never visible from Pole Nascent NASA initiative for a TDRSS follow-on design yet to attract support NASA Space Communications Program under review by National Academy, with report due in early 2007 NSF needs NASA to engage as a strategic planning partner