Radiation Belt Storm Probes RBSP Thermal Design Christopher

Radiation Belt Storm Probes RBSP Thermal Design Christopher Smith RBSP Thermal Engineer Space Sciences Lab University of California, Berkeley RBSP/EFW CDR 2009 9/30 -10/1

Outline • • Requirements APL – UCB Interface Thermal Model Description IDPU Board Level Thermal Analysis Thermal Model Case Set Inputs Current Predicts Current Testing Overview Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Spacecraft Level Thermal Requirements • • Orbit: 500 -675 km x 30, 050 - 31, 250 km (EFW-7, EFW-8) Inclination: 10 degrees +/- 0. 25 (EFW-6) 2 year design life, plus 60 days (EFW-1) Spacecraft top deck pointed to sun within: 25 degrees N/S and E/W, normal operation (EFW-201) 27 degrees composite, normal operation (EFW-202) 33 degrees, Safe mode (SCRD 3. 10. 4. 4) (Was 47) • S/C spin rate (about top deck): 4 to 6 RPM, normal and safe modes (EFW-9) 3 to 15 RPM, instrument commissioning (EFW-203) • S/C shall survive 112 minute eclipse (Derived EFW-6, EFW-7, EFW-8) Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

EFW Thermal Requirements • Conductive external surfaces with 105 Ohms/Sq. (EFW-133) • Contamination: 100, 000 class (EFW-132) • Instruments to operate within specification with -25 to +55 spacecraft boundary conditions. (EFW-76, EFW-77) – -25 to +65 for top deck interface, new since PDR • Instruments to survive without damage with -30 to +60 spacecraft boundary conditions. (EFW-79, EFW-80) – -30 to +70 for top deck interface, new since PDR • Comply with contamination control plan. APL document 74179007. (EFW-132) • Comply with Environmental Design and Test Requirements Document. APL document 7417 -9019. (EFW-136) • Comply with RBSP_EFW_SYS_301_ETM, RBSP engineering test matrix Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Engineering Test Matrix • 7 total cycles per instrument, 5 at component level, 2 at suite level. • Pre-Amps cycled separately due to larger temperature swing. • No need for thermal balance as all instruments are conductively coupled to the spacecraft. Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

APL Thermal Modeling Interface • Berkeley maintains a Thermal Desktop model of the EFW instrument and a boundary node definition of the spacecraft. • APL Maintains a TSS geometry and SINDA network model of the spacecraft. • APL integrates Berkeley geometry via Thermal Desktop TSS export. – Provides environmental heat flux data to instruments. • APL integrates Berkeley SINDA network model into the SINDA spacecraft network model. – APL specifies spacecraft connection nodes. • APL runs integrated model and provides temperature predicts back to Berkeley. • Design cycles as necessary. • APL is responsible for producing high fidelity temperature predicts. Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Thermal Model Overview Instruments and Boundary Spacecraft IDPU AXBs SPBs Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Thermal Model Overview AXB -Stowed Sphere / Preamp in Caging Mechanism (Clear Alodine, Ge. BK Blanket) Sphere / Preamp (DAG 213) Rod to Stacer Hinge (DAG 213) Mounting Tube (M 55 J) Stacer (Elgiloy) Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Thermal Model Overview AXB -Deployed Sphere (DAG 213) Stacer (Elgiloy) DAD (Anti. Sun: Clear Alodine) (Sun: Clear Alodine / Ge. Bk Tape mix) Sphere Caging Mechanism (Anti. Sun: Clear Alodine) (Sun: Ge. Bk Blanket / Clear Alodine mix) Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Thermal Model Overview SPB Deployed Elements SPB Sphere SPB Preamp Thin Wire Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1 Thick Wire

Thermal Model Overview SPB & IDPU SPB - Deployed IDPU (Mostly Black Kapton XC Tape, Some Gold Alodine) (Black Kapton XC Tape) (Clear Alodine) SPB - Stowed (Black Kapton Blanket, Shown in Green) Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

DCB Component Dissipations Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

DFB Component Dissipations Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

LVPS Component Dissipations Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

LVPS Board Distribution Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Optical Materials • Most properties tested, used, and correlated for the THEMIS mission • Properties approved by the GSFC coatings committee July 07, 2008. Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Thermophysical Properties • Hot Cases Use Low e* Anti-Sunward and High e* Sunward • Cold Cases Use High e* Anti-Sunward and Low e* Sunward Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Interfaces IDPU – Conductively mounted to spacecraft side panel. – 9 #10 Bolts = 0. 75 W/C each. – Radiative coupling to spacecraft interior, Black Kapton XCTape SPB – – Conductively mounted to spacecraft side panel. 4 #10 Bolts = 0. 75 W/C each. Deployed elements are completely isolated from the spacecraft by wire. Low radiative coupling to spacecraft interior, Clear Alodined Aluminum AXB – Conductively mounted to the top and bottom spacecraft deck. – 6 #8 Bolts at each end = 0. 75 W/C each. – Radiative coupling somewhat isolated from major portions of the spacecraft since the mechanical units are stowed inside a carbon fiber tube which is also stored inside a spacecraft carbon fiber tube. – Deployed elements are isolated from spacecraft influence by stacer. – Caging mechanisms conductively mounted to top deck, 4 #8 Bolts = 0. 75 W/C each. Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Power, Heaters • Current power used in model • IDPU, SPB and AXB do not have any survival heaters Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

General Case Sets APL Case Set Parameters UCB Case Set Parameters Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Limit Categories • Science Operation Limit – Limits placed on an operating instrument – Specifies the range of temperatures the instrument will provide calibrated / useful science data • Operation – Out of Spec – Limits placed on an operating instrument – May represent a wider range that is survivable but may be out of spec – Temperatures beyond Science Op Limit need not be calibrated to • Non-Operation – Limits placed on a non operating instrument • Pre-Deployment Limit – Limits placed on a mechanical system before it is actuated • Deployment Limit – Limits placed on a mechanical system at the time of actuation • Post-Deployment Limit – Limits placed on a mechanical system after it has executed its one-time deployment Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Current Thermal Limits Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Predicts, Deployed Case Sets Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

Margins, Deployed Case Sets • Positive Margins for all deployed cases Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

APL and UCB Predict Comparison, Table • Each case set compared at a specific time and a representative node • All case sets agree to within 1. 5 degrees Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

APL and UCB Predict Comparison, Plot Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1

ETU Thermal Vac Testing Completed Christopher Smith RBSP/EFW CDR 2009 9/30 -10/1