1. MAXIM Data Systems Command & Data Handling Space - Ground Link Ground System 19 August 1999

2. MAXIM Data Systems Topics lData System Recommendations lOptions and Trades lSpectrum Utilization lGround Antenna Capabilities lData System Drivers lData System Block Diagram lMass/Power Summary lOperations Concept lLink Margin Summary lCost Data lSuggested Study Areas

3. Recommendations for MAXIM !Detector satellite will transmit science data using S-Band to Optics Spacecraft for combined transmission to ground stations !Store data continuously & dump daily for 12 min using DSN 34M using X-Band !Total downlink data rate: 300 Kbps !Use 2:1 data compression !Use S-band for Optics/Detector transmissions !Use S-band for backup comm from DSN for both Optics & Detector

4. Options/Trades !Detector spacecraft to transmit telemetry to Optics spacecraft for combined relay to ground station ( vs separate links) !Less ground station time required !Smaller antenna required for Detector Spacecraft & much simpler communication system !Optics spacecraft sends recorded data vs real time !Ground costs significantly less !Allows good availability on DSN 34M system

5. Options/Trades !DSN 34M recommended (vs 13M commercial) !Allows hi-rate playback !Reduces contact time !Much lower cost !Proven deep space operation !13 M commercial has unproven ranging capability at 40 million Km

6. Spectrum Utilization ØX-band Space to Ground Link Ø(+)Uplink and downlink frequency assignments available Ø(+) More efficient than S-Band (approx 11.5 dB) Ø(+)S/C hardware is available Ø(-) Rain attenuation (approx 2 dB) ØS-band for Optics/Detector link Ø(+ ) More efficient than X-Band (omni/omni) Ø(+) Existing hardware available with modifications of frequency Rx/Tx Ø(+) Allows backup to ground if needed (UHF not readily available) ØS-Band to ground link (emergency) Ø (0) Future allocation in DSN band may be questionable

7. Ground Antenna Capabilities DSN 34M: !X-Band Rx/Tx !G/T = 52.4 dBi/K !EIRP = 103 dBw max(can go to 110 dBw) !S-Band Rx/Tx !G/T = 42.1 dBi/K !EIRP = 98 dBw 13M commercial: ! X-Band Rx/Tx (uplink and ranging need to be added) !G/T = 37 dBi/K !EIRP = 90 dBw !S-Band Rx/Tx !G/T = 24.5 dBi/K !EIRP = 68 dBw

8. MAXIM Data System Drivers lMaximum Range: 40 million KM lDaily Data Volume: 432 Mbits

9. MAXIM Data Systems Block Diagram

10. RF Communications Mass/ Power Optics Spacecraft

11. RF Communications Mass/ Power Detector Spacecraft

12. DSN 34 M BWG (Stations at Canberra, Madrid, Goldstone) MAXIM MOC MAXIM Science Data MAXIM Operations Concept Diagram MAXIM Science X-band Command @ 2 Kbps/Telemetry@ 300 Kbps and Ranging S-band Emergency Command @ 12 bps/Telemetry @ 100 bps S-band command and telemetry @ 4 Kbps Telemetry (Housekeeping/Science) Commands S-band Emergency Command @ 12 bps and telemetry @ 100 bps

13. MAXIM Operations Concept !Detector spacecraft will continuously transmit @ S-Band to Optics spacecraft @ 4 Kbps (3 Kbps science, 1 Kbps housekeeping, uncompressed) !Optics spacecraft will compress 2:1 all Detector data and 1 Kbps Optics housekeeping data !Optics spacecraft will continuously record all compressed data for playback 1/day for 12 min @ 300 Kbps to DSN 34M @ X-Band through 1 of 2 HGA antennas !Nominal commanding/ranging to Optics spacecraft will be done via X-Band through DSN 34M BWG !Both Optics & Detector will have S-Band low-rate command/telemetry through DSN 34M for emergency operations !Commands throughput from MOC, telemetry FTP’d from fileserver

14. MAXIM Link Margin Summary All links have 3 dB required performance margins All links have rate 1/2 convolutional encoding

15. Cost Ground systems: !DSN 34M @ 1hr/day = $365k/yr x 3= $1.1M !13M commercial @ 8 hr/day = $7M Optics Spacecraft: !X Band !XPDRs (2) =$2M !HGA antennas(2)= $2M !S-band !XCVR(4) = $2.8M !omni antennas(4) = $300K !C&DH = $2M

16. Cost(cont’d) ØDetector Spacecraft: !S-band XCVR(2)= 1.4M !omni antennas(2) = $150K

17. Suggested Study Areas,Use of new coding schemes (e.g. Turbo Codes),Modified frequency scheme for S-band XCVR

18. Acronym List lACS - Attitude Control System lACU - Antenna Control Unit lBC - Bus Controller lBWG - Beam Wave Guide lDSN - Deep Space Network lFTP - File Transfer Protocol lHGA - High Gain Antenna lHSKP - housekeeping lI/F - Interface lMOC - Mission Operations Center lRF - Radio Frequency lSSR - Solid State Recorder lXCVR - Transceiver lXPDR - Transponder