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CRaTER Pre-Environmental ReviewInstrument Summary

The CRaTER instrument is located on the LRO science deck as shown in the figure below. A summary of key parameters for the instrument are included in the table below.

CRaTER Placement on the LRO Spacecraft

CRaTER Pre-Environmental Review Page 1 of 17Instrument Summary 30 August 2007

Summary of CRaTER Parameters

Mass Allocation 6.4 kg

Power Consumption Allocation 9.0 W

Size 13.5”x 9” x 6”

Function Tissue equivalent response to radiation

Operational Temperature Range -30о С to +30о С

Data Rate Allocation 89.1 Kbps

The primary goal of CRaTER is to characterize the global lunar radiation environment and its biological impacts. In order to achieve this high-priority objective, the CRaTER investigation team established the following interrelated investigation goals:

1. Measure and characterize that aspect of the deep space radiation environment, linear energy transfer (LET) spectra of galactic and solar cosmic rays (particularly above 10 MeV), most critically important to the engineering and modeling communities to assure safe, long-term, human presence in space.

2. Develop a novel instrument, steeped in flight heritage, that is simple, compact, and comparatively low-cost, but with a sufficiently large geometric factor needed to measure LET spectra and its time variation, globally, in the lunar orbit.

3. Investigate the effects of shielding by measuring LET spectra behind different amounts and types of areal density, including tissue-equivalent plastic.

4. Test models of radiation effects and shielding by verifying/validating model predictions of LET spectra with LRO measurements, using high-quality Galactic Cosmic Ray (GCR) and Solar Proton Event (SPE) spectra available contemporaneously on ongoing/planned NASA.

The investigation hardware consists of a single, integrated sensor and electronics box with simple electronic and mechanical interfaces to the spacecraft. The CRaTER sensor front end design is based on standard stacked-detector, cosmic ray telescope systems that have been flown for decades, using detectors developed for other NASA flight programs. The analog electronics design is virtually identical to the robust and flight-proven design of the NASA/POLAR Imaging Proton Spectrometer that has been operating flawlessly on orbit since 1996. The digital processing unit is a simple and straightforward design also based on similar instruments with excellent spaceflight heritage. No new technology developments or supporting research are required for the final design, fabrication, and operation of this instrument.

The CRaTER telescope consists of six ion-implanted silicon detectors, mounted in pairs and separated by 2 cylinders of tissue-equivalent plastic (TEP). The detectors are all 35 mm in diameter. One of each pair is 140 microns thick; the other of each pair is 1000 microns thick.


CRaTER Assembly Layout

L13.5”x W9” x H 6”Weight 6.4 kg max.

CRaTER Theory of Operation


Summary of Spacecraft Mechanical Requirements flowed to the CRaTER Instrument(Excerpts from the LRO Mechanical Systems Specification, 431-SPEC-000012 Rev D)

Tailored Instrument Limit Loads (based on instrument location)

Instrument Limit Load(g, any direction)

CRaTER 8.0Diviner Instrument 8.0

Diviner DREB 12.0LAMP 9.0LEND 8.0

LOLA OTA 8.0LOLA MEB 9.0LROC NAC 8.0LROC WAC 9.0LROC SCS 8.5

Mini-RF Antenna 12.0Mini-RF Electronics Boxes 12.0

CRATER Instrument X-Axis Sine Vibration Environment

Protoflight/Qualification AcceptanceFrequency (Hz) Level Frequency (Hz) Level

5 - 9.9 1.27 cm D.A. 5 - 8.8 1.27 cm D.A.9.9 - 50 2.5 g’s 8.8 - 50 2.0 g’s

CRATER Instrument Y-Axis Sine Vibration Environment


5 - 15.6 1.27 cm D.A. 5 - 14.0 1.27 cm D.A.15.6 - 25 6.25 g’s 14.0 - 25 5.0 g’s25 - 50 3.125 g’s 25 - 50 2.5 g’s

CRATER Instrument Z-Axis Sine Vibration Environment


5 - 17.1 1.27 cm D.A. 5 - 15.3 1.27 cm D.A.17.1 - 25 7.5 g’s 15.3 - 25 6.0 g’s25 - 50 3.125 g’s 25 - 50 2.5 g’s


Generic Instrument Random Vibration Environment

Frequency (Hz) Protoflight/Qual Level Acceptance Level20 0.026 g2/Hz 0.013 g2/Hz20 - 50 +6dB/Octave +6dB/Octave50 - 800 0.160 g2/Hz 0.080 g2/Hz800 - 2000 -6dB/Octave -6dB/Octave2000 0.026 g2/Hz 0.013 g2/HzOver All 14.1 grms 10.0 grms

CRaTER shock response spectrum

Frequency (Hz) Level (Q=10)100

100 - 10001000 - 10000

15 g+9.3 dB/Octave

525 g


Summary of Spacecraft Thermal Requirements flowed to the CRATER Instrument(Excerpts from the LRO Thermal Systems Specification, 431-SPEC-000091 Rev C)

Spacecraft Interface Temperature Range

Subsystem Component Temperature Range (C)Op I/F Limit Qual I/F Limit Surv I/F Limit

CRATER S/C at I/F to CRATER -30 to +35 -40 to +35 -40 to +35

Temporal Gradient Requirements

Subsystem Component Temporal Gradient (C/min)CRATER S/C I/F to the Instrument None

Spatial Gradient Requirements

Subsystem Component Spatial Gradient between mounting feet (C)CRATER S/C I/F to the Instrument None

(Excerpts from the CRATER to Spacecraft Thermal ICD, 431-ICD-000119 Rev A)

CRATER Reference Location Temperature Limits

# Description Node #Min/Max Temp. Limits (°C)

OPER. SURV. QUAL.1 Telescope Wall CR_XMAX7 -30 to +30 -40 to +50 -40 to +40


LRO Thermal Design Drivers

(External environmental fluxes)

b = 0 case (Noon Orbit, Hot Condition)

Lunar IR environment - Temperature varies – 100

to 400 K (Subsolar point).

View from Sun

b = 90 case (Terminator Orbit, Cold Condition)

Instrument exposed to full direct Solar flux

Lunar IR (~ 150 K continuous)


Summary of Spacecraft Contamination Control Requirements flowed to the CRATER Instrument(Excerpts from the LRO Contamination Control Plan, 431-PLAN-000110 Rev -)

Contamination Budget for LRO Instruments

Instrument Component Delivery To LRO

I&T At Launch Beginning-Of-Life (BOL)

End-Of-Life(EOL)

LOLA Internal Laser1 300 A/2 300 A/2 300 A/2 300 A/2 300 A/2Flight Optics1 300 A/2 300 A/2 300 A/2 300 A/2 300 A/2External Surfaces 450 A/2 450 A/2 450 A 500 A 550 B

LEND External Surfaces 450 A/2 450 A/2 450 A 500 A 550 BLAMP Internal Surfaces1 400 A/20 400 A/20 400 A/20 400 A/20 440 A/15

External Surfaces 450 A/2 450 A/2 450 A 500 A 575 A

LROC External Surfaces 450 A/2 450 A/2 450 A 500 A 550 B

Internal Surfaces1 250 A/5 250 A/5 250 A/5 250 A/5 250 A/5 CRaTER External Surfaces 450 A/2 450 A/2 450 A 500 A 550 BDIVINER Optical Bench

Assembly1400 A/2 400 A/2 400 A/2 400 A/2 450 A

External Surfaces 400 A/2 450 A/2 450 A/2 500 A 550 BMini-RF External Surfaces 450 A/2 450 A/2 450 A 500 A 550 B

Outgassing Requirements for Instruments

LRO Instruments Outgassing Rate or Level (g/cm2/sec) Predicted Max Operating temperature (deg C) at the

S/C InterfaceCRaTER <5.0E-11 35oCLEND Electronics box (ebox) module <5.0E-11

Doppler Aperture <5.0E-1150 oC

LOLA Laser Bench <5 E-13Aft Optics Mod <5.0E-13

Radiator <5.0E-11

35oC45oC

Diviner <2.78 E-11 50oCLAMP <5.0E-11 35oC

LROC/NAC1 <5.0E-11 40oCLROC/NAC2

(same as NAC1)<5.0E-11 40oC

LROC/WAC <5.0E-11 40oCLROC/Radiators <5.0E-11 40oC

Instrument MLI (all) <2.5E-12 g/cm2/sec 40oC


Summary of Spacecraft Electrical Requirements flowed to the CRATER Instrument(Excerpts from the LRO Electrical Systems Specification, 431-SPEC-000008 Rev E)

EMI/EMC Applicability and References

Components ** ESS SectionCE01 X 3.3.1.1CE03 X 3.3.1.1CE06 3.3.1.2RE02 X 3.3.2CS01 X 3.3.3.1CS02 X 3.3.3.2CS03 3.3.3.3CS04 3.3.3.4CS05 3.3.3.5CS06 X 3.3.3.6RS03 X 3.3.4

** Subsystems may be tested as individual components or assemblies where applicable. Subsystems include instruments.

Narrowband Conducted Emissions CE01/CE03 Limits

0

20

40

60

80

100

120

140

1.00E+01 1.00E+02 1.00E+03 1.00E+04 1.00E+05 1.00E+06 1.00E+07 1.00E+08 FREQUENCY (Hz)

dBuA

Instrument or Component Level Test Limits (Differential Mode)

Instrument or Component Level Test Limits (Common Mode)

CE01 (30 Hz - 14 KHz) CE03 (14 KHz-50 MHz)

Bandwidth (Hz) 5 Hz 500 Hz 5 KHz 50 KHz


RE02 Limits for Components that are OFF from launch to vehicle separation

(vertical axis is dBmicrovolts/meter)

20

30

40

50

60

70

80

10

0.01 0.1 1 10 100 1,000 10,000 100,000 Frequency (MHz)

dB uV/m

14 kHz

Components and Instrument Levels (for components and instruments that are OFF from launch to vehicle separation)

30 GHz

20 dB uV/m 2091.3967 +/- 6 MHz

(LRO S-band RX)

8 dB uV/m 2380 +/- 15 MHz

(LRO Mini-RF S-band RX)

8 dB uV/m 7140 +/- 15 MHz (LRO Mini-RF X-

band RX)

CS01/CS02 Limits

2

3

4

5

6

1

0.0001(100 Hz)

0.001(1 kHz)

0.01(10 kHz)

0.1(100 kHz)

1 10 100 1,000

Frequency (MHz)

V rm

s

30 Hz

50 kHz

0.00001(10 Hz)

400 MHz

1.5 kHz2.8 Vrms

1.0 Vrms

2

3

4

5

6

1

0.0001(100 Hz)

0.001(1 kHz)

0.01(10 kHz)

0.1(100 kHz)

1 10 100 1,000

Frequency (MHz)

V rm

s

30 Hz

50 kHz

0.00001(10 Hz)

400 MHz

1.5 kHz2.8 Vrms

1.0 Vrms


CS06 Conducted Susceptibility Test Pulse

Time useconds

40 30 10 50 60 70 80 0 20 0

8

16 Volts

31

40

48

56

64

24

NOTE: The SC Power Bus Pulse shall not exceed 56Vdc at anytime.

10us

25Vdc

CS06 Positive 25Vdc 10uS Pulse

Time useconds

40 30 10 50 60 70 80 0 20 0

8

16 Volts

31

40

48

56

64

24

NOTE: The SC Power Bus Pulse shall not go below 0Vdc at anytime.

10us

CS06 Negative 31Vdc 10uS Pulse


LRO Operational RS Test Limits

Frequency Range Test Level (V/m) Test Level (dBuV/m) Requirement Source14 KHz - 2 GHz 2 126 GSFC-STD-70002 GHz - 12 GHz 5 134 GSFC-STD-700012 GHz - 28 GHz 10 140 GSFC-STD-7000

2.271 GHz +/- 5 MHz 12 142 LRO S-Band Transmitter

25.5 GHz - 28.0 GHz 28 149 LRO Ka-Band Indirect Radiation

2.380 GHz +/- 15 MHz

5 134 LRO Mini-RF S-band Indirect Radiation

7.14 GHz +/- 15 MHz 5 134 LRO Mini-RF X-band Indirect Radiation

Launch Site/Vehicle RS Test Levels

Payload Processing and Launch Pad

EnvironmentFrequency Range V/m dBuV/m Source

14 kHz - 2.700 GHz 20 1462.700 - 2.900 GHz 25 148 GPN-20 & WSR-88D 2.900 - 5.400 GHz 20 1465.400 - 5.900 GHz 40 152 C-Band Tracking

Radars5.900 - 30 GHz 20 146

Atlas V Radiated Emissions

Frequency Range V/m dBuV/m Source14 kHz - 2.206 GHz 20 146

2.206 - 2.216 GHz 20 146 Atlas V Second Stage S-band T/M

2.216 - 5.759 GHz 20 146

5.759 - 5.771 GHz 58 155 Atlas V Second Stage C-band beacon (peak

transmit)5.771 - 30 GHz 20 146


CRATER Deliverables Status Tracking Spreadsheet (as negotiated with LRO Payload Systems Manager and LRO System Assurance Manager)






Documents

LEND Instrument Summary - MITsnebulos.mit.edu/projects/crater/docs/presentations/per... · Web viewMonthly Risk Management Report (can be part of monthly technical progress report)