per crater thermal - massachusetts institute of technology1 lunar reconnaissance orbiter (lro) per...

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Lunar Reconnaissance Orbiter (LRO)PER ThermalJuly 23, 2008

Thermal Design

Charles Baker/545

[email protected]

2NASA’s Goddard Space Flight Center

LRO Thermal/545 23 July 2008

CRaTER Telescope Wall and Radiator I/Fs - Hot Beta 0°

-15

-10

-5

0

5

10

15

20

25

30

35

40

45

0 60 120 180 240 300 360

Time (min)

Tem

p (

°C)

hb00:CRATER.10606 hb00:CRRAD.1016 hb00:CRRAD.1019 hb00:CRRAD.1022

hb00:CRRAD.1064 hb00:CRRAD.1067 hb00:CRRAD.1070

Hot Transient Predicts

Telescope Wall



Radiator Area

• Most radiators have >25% of potential area available– LOLA OTA has 19%– LROC Instruments have 0%

m_ in_ m_ in_ m_ in_

ITP/Avionics 2.54 3933 1.88 2912 0.66 1021 26.0

Battery 0.26 403 0.10 155 0.16 248 61.5

Star Camera 1 0.08 120 0.04 58 0.04 62 51.6

Star Camera 2 0.07 108 0.03 51 0.04 57 52.8

CRaTER 0.18 282 0.09 133 0.10 150 53.1

LEND 0.17 256 0.05 77 0.12 179 69.9

LOLA MEB 0.09 134 0.06 99 0.02 35 26.3

LOLA OTA 0.14 216 0.11 176 0.03 40 18.5

LAMP 0.03 45 0.02 29 0.01 17 36.8

LROC SCS 0.02 25 0.02 25 0.00 0 0.0

LROC WAC 0.02 25 0.02 25 0.00 0 0.0

LROC NACU 0.05 74 0.05 74 0.00 0 0.0

LROC NACL 0.05 74 0.05 74 0.00 0 0.0

Component % AvailableTotal Used Available



Correlated Models StatusComponent Test Correlated Delivered to LRO

Integrated into

Orbiter Model

CRaTER yes yes yes

LEND yes yes yes

LOLA MEB yes yes yes

LOLA OTA yes yes yes

LAMP yes yes yes

LROC SCS yes yes yes

LROC WAC yes yes no

LROC NACU yes yes no

LROC NACL yes yes no

Mini RF - Antenna yes yes yes

Mini RF - Electronics yes yes no

Diviner yes yes yes

Star Camera +X yes yes yes

Star Camera -X yes yes yes

Battery yes yes no

PSE yes yes yes

PDE yes yes yes

C&DH no no no

SA Controller yes yes no

HGA Controller yes yes no

IMU yes yes yes

RWA yes yes yes

S-Band Transponder yes yes yes

Ka-Band TWTA no no no

Ka-Band Modulator no no no

Actuators yes yes yes (HGAS/SAS)



Pending Flight ModelUpdates/Analyses

• Assess off nadir pointing, roll about the X axis (+/-20°) for 20minutes at Beta 0°

• Incorporation of correlated LROC NAC & WAC instrumentmodels

• Creation and incorporation of reduced battery model



Heater Power Summary

Driving Tightest System power margin is Lunar Eclipse

•Avionics Dissipated Power will be 175 W•Total estimated power draw is 456 W versus 605 W allocation

Spacecraft 151 0 105 23 260 65

Propulsion 97 5 95 85 52 67

OB/Instruments* 113 12 125 111 89 66

Deployables 83 83 83 83 83 83

Total 444 100 409 301 484 281

*OB/Instruments operational heaters @ 31V for all cases

HeatersCold Op

B90° (27V)

LE Preheat

(31V)

Lunar Ecl.

(27V)

Hot Op

B0° (31V)

Early Cruise

(27V)

Late Cruise

(31V)


LRO Thermal/545 23 July 2008 7LRO Thermal/545 17 July 2008

7

Test Predicts – Thermal BalanceSpacecraft and Avionics

Balance Predicts(Cold – Hot)

Thermal SoakPredicts (Cold – Hot)

Flight Predicts(Cold – Hot)

Early Cruise TestPredict (Cold)



8

Test Predicts – Thermal BalancePropulsion







Test Predicts – Thermal BalanceDeployables





-70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90

(UpperHousing)

(LowerHousing)

(Hinge Potentiometer)

(Hinge Damper)

(Hinge Rotary Joint)

(HGAS Boom)

(Lower Rotary Joint)

(Lower Actuator)

(Upper Rotary Joint)

(Upper Actuator)

Temperature

[ SAS ]

[ HGAS ]



10

Test Predicts – Thermal BalanceInstrument Interfaces







11

Test Predicts – Thermal BalanceInstruments – Internal Telemetry





[ MINI-RF ]

[ LEND ]

[ LOLA ]



12• DIVINER cold case beta angle differs from spacecraft cold case beta angle

Test Predicts – Thermal BalanceInstruments – Internal Telemetry





[ LROC ]

[ LAMP ]

[ DIVINER ]

[ CRATER ]



Thermal Balance Test Profile

LRO Thermal Balance Test Profile

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 1 2 3 4 5 6 7 8 9

Days

Survival

Cold Op

Ambient

Hot Op

1 - Pump Down

2 - Hot Op Transition

3 - Hot Op Balance

4 - Hot Transient

5 - Hot Prop Test

6 - Cold Op Transition

7 - Cold Op Balance

8 - Lunar Eclipse Warmup

9 - Lunar Eclipse Sim

10 - Lunar Eclipse Followup

11 - Cold Survival Transition

12 - Cold Survival Balance

13 - Cold Prop Test

14 - Cold Start

15 - Transition to Cold Soak #1

16 - Cold Soak #1

17 - Transition to Ambient

6

5

14

11

2

10

9

8

7

3

4

1

13

12

16

15

17



Thermal Cycling Test ProfileLRO Thermal Vacuum Cycling Profile

0

1

2

3

4

5

6

7

8

9

0 2 4 6 8 10 12 14 16

Days

Survival

Qual Cold

Ambient

Qual Hot

Note: Cold Soak #1

completed during

thermal balance

9

2

5

8

10 6

4

13

7

1

3

19

15

14

12

11

17

18

16

1 - Pump Down

2 - Transition to Hot Soak #1

3 - Hot Start

4 - Hot Soak #1


6 - Cold Soak #2

7 - Transtion to Hot Soak #2

8 - Hot Soak #2


10 - Cold Soak #3


12 - Hot Soak #3


14 - Cold Soak #4


16 - Hot Soak #4

17 - Transition to Bakeout

18 - Bakeout

19 - Transition to Ambient



Conclusions

•Test Plan and Test Fixture Build in good shape•All lifts have been dry run•Test Analysis is complete, though will be tweaked thru TRR•Thermal Balance test plan is adequate to demonstrate LRO thermalperformance and correlate the thermal model

•LRO Thermal is on Track for an LRO Orbiter test in mid September

per crater thermal - massachusetts institute of technology1 lunar reconnaissance orbiter (lro) per...

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