Frank StocklinRon Vento

Leslie Ambrose

June 28,2001

SUPERNOVA/ACCELERATIONPROBE (SNAP)

Data Systems

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SNAP June 28, 2001Goddard Space Flight Center

Data SystemsTopics

Overview Driving Requirements and Assumptions Selected Configuration and Rationale Coverage Signal Margin Summary Component Power/Mass/Cost Summary Risk Assessment Issues and Concerns Backup

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SNAP June 28, 2001Goddard Space Flight Center

Data SystemsOverview

Ka-Band downlink @ 55 Mbps continuously (except during eclipse) through a HGA to a ground network consisting of either: Berkeley, CA; Lyon, France; Tokyo, Japan

Single gaps of 18 hours will occur each orbital period of 14 days 18 hour gaps are acceptable at once per orbit

S-Band T&C through omni antennas S-Band ranging using DSN during early maneuvers,

infrequently during the mission Ground terminal sized for maximum range of 69 Re On-board recorder sized for recording spectrograph data

and housekeeping for 24 hours

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SNAP June 28, 2001Goddard Space Flight Center

Launch: Dec 2008 Mission Life: 2 year required, 5 year goal Nominal Orbit: Prometheus 57Re x 19Re @ 40 deg Stellar pointing Instrument Data Collection Rates:

45.2 Mbps Housekeeping rate = 16 Kbps CCSDS compatible (@ 15%) Data storage: 24 hrs/72 Gbits (see C&DH for details)

Data SystemsDriving Requirements &

Assumptions

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SNAP June 28, 2001Goddard Space Flight Center

Data Latency: None Infrequent commanding Telemetry BER =10-6

Rate 1/2 Convolutional/Reed-Solomon encoding Inclination is primary driver CCSDS compatible Redundancy Link margins : 3 dB S/C is jitter sensitive

Data SystemsDriving Requirements &

Assumptions

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SNAP June 28, 2001Goddard Space Flight Center

Data SystemsSelected Configuration &

Rationale Ka-Band

3 gimbaled 0.7m antennas antenna movements between observation periods (every 100-400

seconds) Beamwidth of 1 deg is large enough to provide adequate coverage without

movement during observation periods (will stay close enough to main beam so as not to degrade the link)

located 120 deg apart switchable by on-board command

20 watt TWT(2)- heritage is TDRS H Ka-Band modulators(2)-modification to existing L3 X Band transmitter Data rate = 55 Mbps continuous (includes science, Hskpg, CCSDS &

R/S encoding) S-Band

Omni antennas Transponders(2) Command rate = 2 Kbps Telemetry rate = 1 Kbps

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SNAP June 28, 2001Goddard Space Flight Center

Data SystemsSelected Configuration &

Rationale

Normal operations: Continuous Ka-band transmission Both S-band receivers always on S-band transmitter on as needed

Ground terminals Ground terminals are sized for maximum range of 69 Re Ka-band autotrack will be required Berkeley 11m (modified for Ka-Band) All other sites 10m

Ka-band receive S Band receive/transmit

Radomes highly recommended & included in cost

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SNAP June 28, 2001Goddard Space Flight Center

Data SystemsSelected Configuration &

Rationale

Operational scenario 1(Berkeley,France,Japan) Inclinations < 40 deg Continuous transmission Worst case maximum gap = 18 hours (average outage =12

hours) per orbital period of 14 days(nominal period)

Operational workaround understood to be acceptable with spectrograph data(approx 816 Kbps) recorded on board & played back during visible periods

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SNAP June 28, 2001Goddard Space Flight Center

Data SystemsS/C Antenna Considerations

S-Band Need 2 antennas to enable reliable command & recovery in

case of loss of control & launch phase support Best location is perpendicular to pointing axis(Z)

Ka- Band Need 3 antennas in order to keep the antennas close to the

spacecraft so that the dampening of the movement is quicker Best location is perpendicular to the pointing axis

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SNAP June 28, 2001Goddard Space Flight Center

Data SystemsSelected Configuration &

Rationale

SNAPMOCBerkeley

Science & Hskpg

Command

2 kbps S-Band Cmd

55 Mbps K-Band science1 kbps S-Band hskpg

SNAP

11MK/S

Japan/France

55 Mbps K-Band science1 kbps S-Band hskpg

2 kbps S-Band Cmd

10MK/S

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SNAP June 28, 2001Goddard Space Flight Center

Data SystemsSelected Configuration and

RationaleC

&D

H

S-BandXPNDR

OMNI 1

OMNI 2

CMD/TLM

Data Storage: 9 Gbytes

HGA

Science

Instruments

HGA

S-BandXPNDR

Hybrid

K-Band Modulator(2)

Diplexer

Diplexer

HGA

K-Band Amplifier(2) Switch

OBC

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SNAP June 28, 2001Goddard Space Flight Center

SNAPCoverage Gaps (3 stations)

0

1

0 14 28 42 56 70 84

Days Since Epoch Date

Co

ve

rag

e G

ap

in

Ho

urs

Epoch = Oct 1, 2008Apogee Radius = 66 e.r.Perigee Radius = 7 e.r.Inclination = 0 degArgP = 0RAAN = 0True Anomaly = 0Propagation was Keplerian

(no gaps)

Coverge Gap Example: Berkeley, Lyons, Tokyo

7 x 66 e.r. I ncl = 0 deg

0

1

2

3

4

5

0 14 28 42 56 70 84

Days Since Epoch Date

Co

ve

rag

e G

ap

in

Ho

urs

Coverge Gap Example: Berkeley, Lyons, Tokyo

7 x 66 e.r. I ncl = 20 deg

Epoch = Oct 1, 2008Apogee Radius = 66 e.r.Perigee Radius = 7 e.r.Inclination = 20 degArgP = 0RAAN = 0True Anomaly = 0Propagation was Keplerian

0

5

10

15

20

25

30

35

40

0 14 28 42 56 70 84

Days Since Epoch Date

Co

ve

rag

e G

ap

in

Ho

urs

Coverge Gap Example: Berkeley, Lyons, Tokyo

7 x 66 e.r. I ncl = 65 deg

Epoch = Oct 1, 2008Apogee Radius = 66 e.r.Perigee Radius = 7 e.r.Inclination = 65 degArgP = 0RAAN = 0True Anomaly = 0Propagation was Keplerian

0

3

6

9

12

15

18

0 14 28 42 56 70 84

Days Since Epoch Date

Co

ve

rag

e G

ap

in

Ho

urs

Coverge Gap Example: Berkeley, Lyons, Tokyo

7 x 66 e.r. I ncl = 40 deg

Epoch = Oct 1, 2008Apogee Radius = 66 e.r.Perigee Radius = 7 e.r.Inclination = 40 degArgP = 0RAAN = 0True Anomaly = 0Propagation was Keplerian

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SNAP June 28, 2001Goddard Space Flight Center

SNAP Signal Margins (Max Range = 69 Re)

Mode Data Rate Margin (dB)Max Range

Antennas

K-band 55 Mbps 3.0 dB .7 m HGA

S-band Cmd 2 kbps 8.9 dB Omni

S-band Tlm 1 kbps 3.4 dB Omni

S-band Ranging Uplink ---- 6.4 dB Omni

S-band RangingDownlink

---- 2.8 dB Omni

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SNAP June 28, 2001Goddard Space Flight Center

Data Systems Component Power/Mass/Cost

Summary

Component Power (peak/ avg)

Mass Cost

S-band Omni antenna (2)

----- 2 kg

S-band Transponders (2)

41/ 17 watts

8 kg

Diplexers(2), Miscellaneous

----- 2 kg

K-Band HGA antenna(3)

----- 30 kg

K Band Power Amps(2)

60 watts continuous (50 watts on,

10 watts standby)

6 kg

K-Band Modulators (2)

20/ 20 watts 5 kg

Total 121/ 97 watts 53.0 kg

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SNAP June 28, 2001Goddard Space Flight Center

Data SystemsRisk Assessment

Construction, Maintenance and operation of 10M Ka/S-band stations: Low to Medium Risk

K-band Modulator: Modified design of current X-band transmitter: Low to Medium Risk

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Data SystemsIssues and Concerns

During 5 year period the apogee/perigee/inclination will vary Apogee up to 69 Re Perigee down to 7 Re Inclination down to 0 deg & up to 65 deg Shape of the orbit If the inclination increases coverage gap times will increase

(gaps greater than 18 hours will occur when the inclination increases above 40 deg.)

Location of apogee and perigee (dependent on possible inclinations)

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Data SystemsSNAP

Back-Up Charts

Data SystemsPage 18

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SNAP Ka-Band 10 M Downlink (55 Mbps)

GSFC C.L.A.S.S. ANALYSIS #SNAP2 DATE & TIME: 6/27/ 1 13:53:28 PERFORMED BY: R. VENTO LINKID: SNAP FREQUENCY: 26000.0 MHz RANGE: 438929.8 km

MODULATION: QPSK I CHANNEL Q CHANNEL --------- --------- DATA RATE: 27500.000 kbps DATA RATE: 27500.000 kbps CODING: RATE 1/2 WITH RS ENCODING CODING: RATE 1/2 WITH RS ENCODING BER: 1.00E-06 BER: 1.00E-06 98% coverage at Japan (worst case rain attenuation) 20 watt S/C transmitter with a 0.7 M antenna

PARAMETER VALUE REMARKS ------------------------------------------------------------------------------------------------------------------------

01. USER SPACECRAFT TRANSMITTER POWER - dBW 13.01 NOTE A; 20.0 WATTS 02. USER SPACECRAFT PASSIVE LOSS - dB 2.00 NOTE A 03. USER SPACECRAFT ANTENNA GAIN - dBi 43.01 NOTE A 04. USER SPACECRAFT POINTING LOSS - dB .00 NOTE A 05. USER SPACECRAFT EIRP - dBWi 54.02 1 - 2 + 3 - 4 06. POLARIZATION LOSS - dB .30 NOTE A 07. FREE SPACE LOSS - dB 233.59 ALT: 433704 KM,EL:10.0 DEG 08. ATMOSPHERIC LOSS - dB 1.48 NOTE B 09. RAIN ATTENUATION - dB 4.72 NOTE A 10. MULTIPATH LOSS - dB .00 NOTE A 11. GROUND STATION ANTENNA GAIN - dBi 66.11 10.0 M, EFF: 55.0% 12. GROUND STATION PASSIVE LOSS - dB .00 NOTE A 13. GROUND STATION POINTING LOSS - dB .00 NOTE A 14. SYSTEM NOISE TEMPERATURE - dB-DEGREES-K 23.01 NOTE A 15. GROUND STATION G/T - dB/DEGREES-K 43.10 11 - 12 - 13 - 14 16. BOLTZMANN'S CONSTANT - dBW/(Hz*K) -228.60 CONSTANT 17. RECEIVED CARRIER TO NOISE DENSITY - dB/Hz 85.64

I CHANNEL Q CHANNEL --------- --------- 18. I-Q CHANNEL POWER SPLIT LOSS - dB 3.01 3.01 1.00 TO 1.00 19. MODULATION LOSS - dB .00 .00 NOTE A 20. DATA RATE - dB-bps 74.39 74.39 NOTE A 21. DIFFERENTIAL ENCODING/DECODING LOSS - dB .00 .00 NOTE A 22. USER CONSTRAINT LOSS - dB .00 .00 NOTE A 23. RECEIVED Eb/No - dB 8.23 8.23 24. IMPLEMENTATION LOSS - dB 2.00 2.00 NOTE A 25. REQUIRED Eb/No - dB 3.20 3.20 I: Q: NOTE B 26. REQUIRED PERFORMANCE MARGIN - dB .00 .00 NOTE A 27. MARGIN - dB 3.03 3.03 23 - 24 - 25 - 26

NOTE A: PARAMETER VALUE FROM USER PROJECT - SUBJECT TO CHANGE NOTE B: FROM CLASS ANALYSIS IF COMPUTED

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SNAP June 28, 2001Goddard Space Flight Center

SNAP S-Band 10M Uplink (2 kbps) DATE & TIME: 06/27/01 14:34: 7 SNAP COMMAND UPLINK FREQUENCY - 2106.400 MHZ GROUND ANTENNA - - - 10 METER POWER - 2.0000 K WATTS

--------------------------------------------------------------------------- PARAMETERS UNITS VALUES ESTIMATED TOLERANCES (MAX RNG: (MIN RNG: DB 438929.76 KM 38268.00 KM 10.0 EL) 90.0 EL) FAV ADV --------------------------------------------------------------------------- EFFECTIVE RADIATED POWER DBM 108.0 108.0 1.0 -1.0 FREE SPACE DISPERSION LOSS DB -211.8 -190.6 .0 .0 ATMOSPHERIC LOSS DB -.3 .0 .0 .0 POLARIZATION LOSS DB -1.0 -1.0 .0 .0 SPACECRAFT ANTENNA GAIN DBI 3.0 3.0 .0 .0 SPACECRAFT PASSIVE LOSS DB -5.0 -5.0 .5 -.5 MAXIMUM TOTAL RECEIVED POWER DBM -107.1 -85.6 1.1 -1.1 SPACECRAFT ANTENNA NULL DEPTH DB -6.0 -6.0 .0 .0 MINIMUM TOTAL RECEIVED POWER DBM -113.1 -91.6 1.1 -1.1 SYSTEM NOISE DENSITY DBM/HZ -171.6 -171.6 .0 .0 IF NOISE BANDWIDTH( 3000.000 KHZ) DB-HZ 64.8 64.8 .0 .0 IF NOISE POWER DBM -106.8 -106.8 .0 .0 IF SNR (MIN) DB -6.3 15.2 1.1 -1.1

--------------------------------------------------------------------------- CARRIER CHANNEL ------- ------- CARRIER/TOTAL POWER DB -5.8 -5.8 .6 -.6 RECEIVED CARRIER POWER DBM -118.9 -97.4 1.3 -1.3 CARRIER LOOP NOISE BW( 800. HZ) DB-HZ 29.0 29.0 .0 .0 NOISE POWER DBM -142.6 -142.6 .0 .0 CARRIER/NOISE DB 23.7 45.2 1.3 -1.3 REQUIRED CARRIER/NOISE DB 15.0 15.0 .0 .0 AVAILABLE CARRIER MARGIN DB 8.7 30.2 1.3 -1.3 REQUIRED PERFORMANCE MARGIN DB 3.0 3.0 .0 .0

NET MARGIN DB 5.7 27.2 1.3 -1.3

--------------------------------------------------------------------------- COMMAND CHANNEL (PCM/PSK/PM) ------- ------- ------------ COMMAND/TOTAL POWER(MI=1.50 RAD) DB -2.1 -2.1 .2 -.2 RECEIVED COMMAND POWER DBM -115.2 -93.7 1.1 -1.1 PREDETECTION (PSK) NOISE BW(32.000 KHZ) DB-HZ 45.1 45.1 .0 .0 PREDETECTION (PSK) NOISE POWER DB -126.5 -126.5 .0 .0 PREDETECTION (PSK) SNR DB 11.3 32.8 1.1 -1.1 COMMAND DATA RATE ( 2.000KBPS) DB-BPS 33.0 33.0 .0 .0 AVAILABLE ENERGY PER BIT/NOISE DENSITY DB 23.4 44.9 1.1 -1.1 DECODER DEGRADATION DB -2.0 -2.0 .0 .0 REQUIRED ENERGY PER BIT/NOISE DENSITY (BER=E-5) DB 10.5 10.5 .0 .0 AVAILABLE COMMAND MARGIN DB 10.9 32.4 1.1 -1.1 - --- IMPLEMENTATION LOSS DB 2.0 2.0 REQUIRED PERFORMANCE MARGIN DB 0.0 0.0 .0 .0

NET MARGIN DB 8.9 30.4 1.1 -1.1 --------------------------------------------------------------------------- snap4

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SNAP June 28, 2001Goddard Space Flight Center

SNAP S-Band Downlink (2 Kbps) DATE & TIME: 06/27/01 14:54:13 SNAP DOWNLINK FREQUENCY - 2287.500 MHZ GROUND ANTENNA - - - 10 METER POWER - 5.00 WATTS --------------------------------------------------------------------------- PARAMETERS UNITS VALUES ESTIMATED TOLERANCES (MAX RNG: (MIN RNG: DB 438929.76 KM 38268.00 KM 10.0 EL) 90.0 EL) FAV ADV --------------------------------------------------------------------------- TOTAL TRANSMITTER POWER DBM 37.0 37.0 1.0 -1.0 SPACECRAFT PASSIVE LOSSES DB -4.5 -4.5 .5 -.5 SPACECRAFT ANTENNA GAIN DBI 3.0 3.0 .0 .0 FREE SPACE DISPERSION LOSS DB -212.5 -191.3 .0 .0 ATMOSPHERIC LOSS DB -.2 .0 .0 .0 STDN ANTENNA GAIN (EFFECTIVE) DBI 45.0 45.0 .0 .0 COMBINER LOSS DB -.5 -.5 .0 .0 POLARIZATION LOSS DB .0 .0 .0 .0 MAXIMUM TOTAL RECEIVED POWER DBM -132.7 -111.3 1.1 -1.1 SPACECRAFT ANTENNA NULL DEPTH DB -6.0 -6.0 .0 .0 MINIMUM TOTAL RECEIVED POWER DBM -138.7 -117.3 1.1 -1.1 SYSTEM NOISE DENSITY DBM/HZ -178.6 -178.6 .0 .0 IF NOISE BW( 100.000 KHZ) DB-HZ 50.0 50.0 .0 .0 IF SNR (MIN) DB -10.1 11.3 1.1 -1.1 --------------------------------------------------------------------------- CARRIER CHANNEL ------- ------- CARRIER/TOTAL POWER DB -8.8 -8.8 .9 -.9 RECEIVED CARRIER POWER (MIN) DBM -147.5 -126.1 1.4 -1.4 CARRIER LOOP NOISE BANDWIDTH( 10. HZ) DB-HZ 10.0 10.0 .0 .0 NOISE POWER DBM -168.6 -168.6 .0 .0 CARRIER/NOISE DB 21.1 42.5 1.4 -1.4 REQUIRED CARRIER/NOISE DB 15.0 15.0 .0 .0 AVAILABLE CARRIER MARGIN DB 6.1 27.5 1.4 -1.4 REQUIRED PERFORMANCE MARGIN DB 3.0 3.0 .0 .0

NET MARGIN DB 3.1 24.5 1.4 -1.4

--------------------------------------------------------------------------- DATA CHANNEL (PCM/PM) ---- ------- -------- DATA/TOTAL POWER(MI=1.20 RAD) DB -.6 -.6 .1 -.1 RECEIVED DATA POWER (MIN) DBM -139.3 -117.9 1.1 -1.1 INFORMATION RATE( 2.000 KBPS) DB-BPS 33.0 33.0 .0 .0 AVAILABLE SIGNAL/NOISE DENSITY DB-HZ 39.3 60.7 1.1 -1.1 REQUIRED ENERGY PER BIT/NOISE DENSITY (BER= E-5 ) DB 2.9 2.9 .0 .0 REQUIRED SIGNAL/NOISE DENSITY DB-HZ 35.9 35.9 .0 .0 AVAILABLE SIGNAL MARGIN DB 3.4 24.8 1.1 -1.1- IMPLEMENTATION LOSS DB 2.O 2.0 REQUIRED PERFORMANCE MARGIN DB 0.0 00 .0 .0

NET MARGIN DB 1.4 22.8 1.1 -1.1 SNAP6 ---------------------------------------------------------------------------1

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SNAP June 28, 2001Goddard Space Flight Center

SNAP S-Band Downlink (1 kbps)

DATE & TIME: 06/27/01 14:54:13 SNAP DOWNLINK FREQUENCY - 2287.500 MHZ GROUND ANTENNA - - - 10 METER POWER - 5.00 WATTS --------------------------------------------------------------------------- PARAMETERS UNITS VALUES ESTIMATED TOLERANCES (MAX RNG: (MIN RNG: DB 438929.76 KM 38268.00 KM 10.0 EL) 90.0 EL) FAV ADV --------------------------------------------------------------------------- TOTAL TRANSMITTER POWER DBM 37.0 37.0 1.0 -1.0 SPACECRAFT PASSIVE LOSSES DB -4.5 -4.5 .5 -.5 SPACECRAFT ANTENNA GAIN DBI 3.0 3.0 .0 .0 FREE SPACE DISPERSION LOSS DB -212.5 -191.3 .0 .0 ATMOSPHERIC LOSS DB -.2 .0 .0 .0 STDN ANTENNA GAIN (EFFECTIVE) DBI 45.0 45.0 .0 .0 COMBINER LOSS DB -.5 -.5 .0 .0 POLARIZATION LOSS DB .0 .0 .0 .0 MAXIMUM TOTAL RECEIVED POWER DBM -132.7 -111.3 1.1 -1.1 SPACECRAFT ANTENNA NULL DEPTH DB -6.0 -6.0 .0 .0 MINIMUM TOTAL RECEIVED POWER DBM -138.7 -117.3 1.1 -1.1 SYSTEM NOISE DENSITY DBM/HZ -178.6 -178.6 .0 .0 IF NOISE BW( 100.000 KHZ) DB-HZ 50.0 50.0 .0 .0 IF SNR (MIN) DB -10.1 11.3 1.1 -1.1 --------------------------------------------------------------------------- CARRIER CHANNEL ------- ------- CARRIER/TOTAL POWER DB -8.8 -8.8 .9 -.9 RECEIVED CARRIER POWER (MIN) DBM -147.5 -126.1 1.4 -1.4 CARRIER LOOP NOISE BANDWIDTH( 10. HZ) DB-HZ 10.0 10.0 .0 .0 NOISE POWER DBM -168.6 -168.6 .0 .0 CARRIER/NOISE DB 21.1 42.5 1.4 -1.4 REQUIRED CARRIER/NOISE DB 15.0 15.0 .0 .0 AVAILABLE CARRIER MARGIN DB 6.1 27.5 1.4 -1.4 REQUIRED PERFORMANCE MARGIN DB 3.0 3.0 .0 .0

NET MARGIN DB 3.1 24.5 1.4 -1.4

--------------------------------------------------------------------------- DATA CHANNEL (PCM/PM) ---- ------- -------- DATA/TOTAL POWER(MI=1.20 RAD) DB -.6 -.6 .1 -.1 RECEIVED DATA POWER (MIN) DBM -139.3 -117.9 1.1 -1.1 INFORMATION RATE( 1.000 KBPS) DB-BPS 30.0 30.0 .0 .0 AVAILABLE SIGNAL/NOISE DENSITY DB-HZ 39.3 60.7 1.1 -1.1 REQUIRED ENERGY PER BIT/NOISE DENSITY (BER= E-5 ) DB 2.9 2.9 .0 .0 REQUIRED SIGNAL/NOISE DENSITY DB-HZ 32.9 32.9 .0 .0 AVAILABLE SIGNAL MARGIN DB 6.4 27.8 1.1 -1.1- IMPLEMENTATION LOSS DB 2.O 2.0 REQUIRED PERFORMANCE MARGIN DB 0.0 0.0 .0 .0

NET MARGIN DB 4.4 25.8 1.1 -1.1 SNAP6 ---------------------------------------------------------------------------1

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SNAP June 28, 2001Goddard Space Flight Center

SNAP S-band Ranging Up-link

UPLINK DATE & TIME: 06/27/01 15: 7: 6 SNAP RANGING FREQUENCY - 2106.400 MHZ GROUND ANTENNA - - - 26 METER DSN POWER - 10.0000 K WATTS

--------------------------------------------------------------------------- PARAMETERS UNITS VALUES ESTIMATED TOLERANCES (MAX RNG: (MIN RNG: DB 438929.76 KM 38268.00 KM 10.0 EL) 90.0 EL) FAV ADV --------------------------------------------------------------------------- EFFECTIVE RADIATED POWER DBM 121.5 121.5 1.0 -1.0 FREE SPACE DISPERSION LOSS DB -211.8 -190.6 .0 .0 ATMOSPHERIC LOSS DB -.3 .0 .0 .0 POLARIZATION LOSS DB -1.0 -1.0 .0 .0 SPACECRAFT ANTENNA GAIN DBI 3.0 3.0 .0 .0 SPACECRAFT PASSIVE LOSS DB -4.0 -4.0 .4 -.4 MAXIMUM TOTAL RECEIVED POWER DBM -92.6 -71.1 1.1 -1.1 SPACECRAFT ANTENNA NULL DEPTH DB -6.0 -6.0 .0 .0 MINIMUM TOTAL RECEIVED POWER DBM -98.6 -77.1 1.1 -1.1 SYSTEM NOISE DENSITY DBM/HZ -171.6 -171.6 .0 .0 IF NOISE BANDWIDTH( 3000.000 KHZ) DB-HZ 64.8 64.8 .0 .0 IF NOISE POWER DBM -106.8 -106.8 .0 .0 IF SNR (MIN) DB 8.2 29.7 1.1 -1.1 --------------------------------------------------------------------------- CARRIER CHANNEL ------- ------- CARRIER/TOTAL POWER DB -2.2 -2.2 .2 -.2 RECEIVED CARRIER POWER DBM -100.8 -79.3 1.1 -1.1 CARRIER LOOP NOISE BW( 800. HZ) DB-HZ 29.0 29.0 .0 .0 NOISE POWER DBM -142.6 -142.6 .0 .0 CARRIER/NOISE DB 41.8 63.3 1.1 -1.1 REQUIRED CARRIER/NOISE DB 15.0 15.0 .0 .0 AVAILABLE CARRIER MARGIN DB 26.8 48.3 1.1 -1.1 REQUIRED PERFORMANCE MARGIN DB 3.0 3.0 .0 .0

NET MARGIN DB 23.8 45.3 1.1 -1.1

--------------------------------------------------------------------------- TONE RANGING W/MOD INDEX ---- ------- - --- ----- RANGING/TOTAL POWER(MI= .70 RAD) DB -7.7 -7.7 .8 -.8 RECEIVED RANGING POWER DBM -106.3 -84.8 1.3 -1.3 RECEIVED SIGNAL/NOISE DENSITY DB-HZ 65.3 86.8 1.3 -1.3 REQUIRED SIGNAL/NOISE DENSITY DB-HZ 55.9 55.9 .0 .0 REQUIRED PERFORMANCE MARGIN DB 3.0 3.0 .0 .0

NET MARGIN DB 6.4 27.9 1.3 -1.3 SNAP14 ---------------------------------------------------------------------------1

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SNAP June 28, 2001Goddard Space Flight Center

SNAP S-band Ranging Downlink

DOWNLINK DATE & TIME: 06/27/01 15: 7: 6 SNAP RANGING FREQUENCY - 2287.500 MHZ GROUND ANTENNA - - - 26 METER DSN POWER - 5.00 WATTS --------------------------------------------------------------------------- PARAMETERS UNITS VALUES ESTIMATED TOLERANCES (MAX RNG: (MIN RNG: DB 438929.76 KM 38268.00 KM 10.0 EL) 90.0 EL) FAV ADV --------------------------------------------------------------------------- TOTAL TRANSMITTER POWER DBM 37.0 37.0 1.0 -1.0 SPACECRAFT PASSIVE LOSSES DB -4.0 -4.0 .4 -.4 SPACECRAFT ANTENNA GAIN DBI 3.0 3.0 .0 .0 FREE SPACE DISPERSION LOSS DB -212.5 -191.3 .0 .0 ATMOSPHERIC LOSS DB -.2 .0 .0 .0 STDN ANTENNA GAIN (EFFECTIVE) DBI 52.5 52.5 .0 .0 COMBINER LOSS DB -.5 -.5 .0 .0 POLARIZATION LOSS DB .0 .0 .0 .0 MAXIMUM TOTAL RECEIVED POWER DBM -124.7 -103.3 1.1 -1.1 SPACECRAFT ANTENNA NULL DEPTH DB -6.0 -6.0 .0 .0 MINIMUM TOTAL RECEIVED POWER DBM -130.7 -109.3 1.1 -1.1 SYSTEM NOISE DENSITY DBM/HZ -177.2 -177.7 .0 .0 TURNAROUND NOISE DENSITY DBM/HZ -216.2 -215.8 .0 .0 TOTAL NOISE DENSITY DBM/HZ -177.2 -177.7 .0 .0 IF NOISE BW( 3000.000 KHZ) DB-HZ 64.8 64.8 .0 .0 IF SNR (MIN) DB -18.3 3.6 1.1 -1.1 --------------------------------------------------------------------------- CARRIER CHANNEL ------- ------- CARRIER/TOTAL POWER DB -.4 -.4 .0 .0 RECEIVED CARRIER POWER (MIN) DBM -131.1 -109.7 1.1 -1.1 CARRIER LOOP NOISE BANDWIDTH( 10. HZ) DB-HZ 10.0 10.0 .0 .0 NOISE POWER DBM -167.2 -167.7 .0 .0 CARRIER/NOISE DB 36.1 58.0 1.1 -1.1 REQUIRED CARRIER/NOISE DB 15.0 15.0 .0 .0 AVAILABLE CARRIER MARGIN DB 21.1 43.0 1.1 -1.1 REQUIRED PERFORMANCE MARGIN DB 3.0 3.0 .0 .0

NET MARGIN DB 18.1 40.0 1.1 -1.1

--------------------------------------------------------------------------- TONE RANGING-ACQ (PM) ---- ------- --- ---- RANGING/TOTAL POWER (MAX RNG MI = .269 RAD, (MIN RNG MI = .284 RAD) DB -14.7 -14.2 1.0 -1.0 TRANSPONDER DEGRADATION DB .0 .0 .0 .0 RECEIVED RANGING POWER (MIN) DBM -145.4 -123.5 1.5 -1.5 AVAILABLE RANGING/NOISE DENSITY DB-HZ 31.8 54.2 1.5 -1.5 REQUIRED SIGNAL/NOISE DENSITY (RMS RANGE ERROR = 4.0 M) DB-HZ 26.0 26.0 .0 .0 AVAILABLE SIGNAL MARGIN DB 5.8 28.2 1.5 -1.5 REQUIRED PERFORMANCE MARGIN DB 3.0 3.0 .0 .0

NET MARGIN DB 2.8 25.2 1.5 -1.5 SNAP15 ---------------------------------------------------------------------------1