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Mars Atmosphere and Volatile EvolutioN (MAVEN) Mission. Particles and Fields Package Peer Review May 8 -10, 2011 Christopher Smith, Thermal Engineer. Initial Work Flow. UCB builds individual instrument thermal models SWIA, STATIC, SEP, LPW, PFDPU, and SWEA

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Mars Atmosphere and Volatile EvolutioN (MAVEN) Mission

Particles and Fields Package

Peer Review

May 8 -10, 2011

Christopher Smith, Thermal Engineer


Initial work flow
Initial Work Flow

UCB builds individual instrument thermal models

SWIA, STATIC, SEP, LPW, PFDPU, and SWEA

UCB submits these models to spacecraft provider (LM) who incorporates them into the spacecraft thermal model.

LM generates sink couplings for each instrument node for environments and delivers these to UCB

UCB incorporates LM environments and goes through a design cycle to meet ERD requirements.

UCB returns new generation of instrument models to LM. Cycle repeats as necessary

LM responsible for producing official predicts for mission


Interface issues
Interface Issues

LM unhappy with UCB thermal models

LM required, and UCB agreed to, ~50 node instrument models

UCB thermal engineer provided ~200 to 300 node instrument models

LM chooses to reduce UCB thermal models in house due to limited thermal support by UCB at the time

LM provides results and sinks back to UCB for the reduced instrument model

UCB not happy because this requires a lot of monkeying around to get to work with full instrument models

UCB not happy with only hot and cold case sinks provided

LM reduced thermal models contain potential for error as they were not produced by UCB

After much discussion LM releases full spacecraft model for use by the instrument teams

Includes their full case set definitions


Current work flow
Current Work Flow

UCB builds individual instrument thermal models (DONE)

SWIA, STATIC, SEP, LPW, PFDPU, and SWEA

LM provides sink temperatures for UCB boundary node spacecraft

UCB modifies instruments to meet requirements in all provided environments (DONE)

UCB submits these models to spacecraft provider (LM) who incorporates them into the spacecraft thermal model. (DONE)

LM returns spacecraft thermal model with integrated instrument models (DONE)

LM had some issues, so far it looks like they are all modeling problems with the reduced instrument models (IN PROGRESS)

UCB uses spacecraft model to address any issues and returns updates to LM (IN PROGRESS)

LM responsible for producing official predicts for mission


Current status
Current Status

Not yet at CDR level with instrument predicts (Complete By CDR)

Spacecraft model running at UCB with full instrument models integrated

All the gross errors are worked out but needs more work to assure everything is running well

Deep Dip and Thruster heating still in spreadsheet form (Complete By CDR)

Spacecraft case sets include proper deep dip environments

Need to add thruster heating

LPW boom thermal treatment un-resolved

Black Nickel originally specified but it alters the mechanical behavior of the boom

DAG 213 a possibility but susceptible to AO degradation

Without a high emissivity surface stacer over heats in deep dips

PFDPU board analysis not complete (Complete By CDR?)

RBSP LVPS board overheating

No real board level thermal analysis done for RBSP

Issues with RBSP need to be addressed on PFDPU boards


Environmental loads
Environmental Loads

Values above from LM Case Sets

Thruster flux combination of ACS and TCM firings


Optical properties
Optical Properties

All Materials approved by GSFC and JPL on previous missions

Added testing for AO exposure

Clear Alodine done by one plater with specified soak time. Extensive sampling with THEMIS. Occasional sampling with other missions. Wide BOL/EOL variance assumed in design


Thermophysical properties
Thermophysical Properties

Values above from LM Case Sets

Thruster flux combination of ACS and TCM firings



Swia thermal model
SWIA Thermal Model

Germanium Black Kapton Blanket

Black Nickel

+ Grid (Not Shown)

Blanket,

1.5 Sides Black Nickel

Power Dissipation: 1.85 W +/- 15%

Mass: 2.5 kg

Conduction to SC Isolated

4 #8 Titanium with .25" G10

Isolator = .013 W/C each


Static thermal model
STATIC Thermal Model

Germanium Black Kapton Blanket

Black Nickel

+ Grid (Not Shown)

Blanket,

1 Side Black Nickel

Power Dissipation: 3.96 W +/- 15%

Mass: 2.9 kg

Conduction to APPIsolated

4 #8 Titanium with .25" G10

Isolator = .013 W/C each


Swea thermal model
SWEA Thermal Model

Blanket

Black Nickel

50 % Blanket

50% Black Nickel

Power Disipation: .89 W +/- 15%

Mass: 1.8 kg

SC Balance Mass: ~ 17 kg

Conduction to SC Isolated

4 #8 Titanium with .25" G10

Isolator = .013 W/C each

Blanketed Balance Mass


Sep thermal model
SEP Thermal Model

Blanket

White Paint,

Z-93-C55

Power Disipation: .016 W +/- 15%

Mass: .63 kg

White Paint,

Z-93-C55

Conduction to SC Isolated

4 #8 Titanium with .25" ULTEM 1000

Isolator = .011 W/C each


Pfdpu thermal model
PFDPU Thermal Model

Black Nickel?

Boards to Frame Conduction:

Epoxied to frame at lip = .386 W/C

8 #4 Screws (screw path only)=.1 W/C total

Frame Conduction to Adapter Plate:

22 #6 screws 0.42 = 9.24 W/C

Adapter Plate Conduction to SC:

6 #10 bolts 1.32 each = 7.92 W/C

Simple Distributed Board Models

Power Disipation: 12.1 W +/- 15%

Mass: 5.9 kg


Lpw thermal model
LPW Thermal Model

Whip

PreAmp

Power: .015 W +/- 15%

Stowed Stacer and DAD

Mass: 2.6kg

Base Mech to Bracket Conductance:

6 #8 Ti with .25" G10 Isolator = .013 W/C each


Lpw thermal model1
LPW Thermal Model

Clear Alodine

(Inside Spacecraft Body Blanket)

DAG 213?

Titanium Nitride


Spacecraft thermal model
Spacecraft Thermal Model

Full Spacecraft Model

  • Boundary Node Spacecraft

  • All Surface Temps from LM Output

  • MLI Unbound









Lockheed thermal memos 1
Lockheed Thermal Memos #1

  • STATIC Modeling problem fixed, now looks ok

  • SEP modeling issue found, LM Notified and producing new predicts


Lockheed thermal memos 2
Lockheed Thermal Memos #2

  • No Issues, but not yet correlated with UCB run


Lockheed thermal memos
Lockheed Thermal Memos

  • No Issues, but not yet correlated with UCB run


Rbsp lvps thermal issue
RBSP LVPS Thermal Issue

PWM chip on RBSP LVPS was running 60 C above the box temp and was running at 90 C before thermal vac test was aborted

Investigation revealed several issues

Board mounting standoffs were G10 instead of Aluminum

EMI shield was Alodined Aluminum shutting off radiation

More importantly ground / thermal planes did not connect to the mounting areas


Rbsp resolution
RBSP Resolution

RBSP issue solved

Removed resistors dissapating1 watt from board, will mount to side of box

Turned radiation back on with black paint

Built a detailed thermal model of board and correlated its performance with testing

12 layer FR4 board

12 layers of FR4 in Model .093” / 12 = 0.00775” thick

Conductors between FR4 layers

Board contains 7, 3-oz Ground Planes

All ground planes are partial though they cover most of the board

7 Separate ground planes in model 0.0042” thick

Conductors from each ground layer to the FR4 layer above and the layer below

Individual components dissipating more than .1 W modeled


Pfdpu way forward
PFDPU Way Forward

Create detailed thermal model of high dissipation boards

Current simple distributed property model is a good start

Thermal / Ground planes need to grow as much as possible and overlap as much as possible.

Thermal planes need to be brought to the edge of the board

Maintain electrical isolation while improving thermal connections much as possible


Lpw stacer
LPW Stacer

LPW Stacer needs to be black to help reject deep dip heat load

Black Nickel was identified as a candidate and sent out for AO testing and it did well

However when it was applied to a stacer it modified its mechanical behavior

DAG 213 was identified as an alternative

We have lots of experience with it and has been used on stacers before

Unfortunately DAG 213 was completely eroded after AO testing


Backup slides
Backup Slides

Back Up Slides


Requirements documents
Requirements Documents

Performance Requirements Document

MAVEN-program-plan-appendix-v28_L1Req.doc (Level 1)

MAVEN-PM-RQMT-0005, Mission Requirements (Level 2)

MAVEN-PFIS-RQMT-0016, PFP Requirements (Level 3)

MAVEN-PF-STATIC-001A-Requirements_&_Specifications.xls (Level 4)

Mission Assurance Requirements

MAVEN-PM-RQMT-0006, Mission Assurance Requirements

MAVEN_PF_QA_002, PFP Mission Assurance Implementation Plan

Mission Operations

MAVEN-MOPS-RQMT-0027, Mission Operations Requirements

Environmental Requirements Document

MAVEN-SYS-RQMT-0010

Spacecraft to PFP ICD

MAVEN-SC-ICD-0007


Lm launch initial acquisition case definitions
LM Launch/Initial Acquisition Case Definitions


Lm cruise case definitions
LM Cruise Case Definitions


Lm moi case definitions
LM MOI Case Definitions


Lm science case definitions
LM Science Case Definitions

Science Cases

Deep Dip Cases


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