1 / 18

Thermal Design

Thermal Design. Christopher Smith RBSP Thermal Engineer Space Sciences Lab University of California, Berkeley. 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)

Download Presentation

Thermal Design

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Thermal Design Christopher Smith RBSP Thermal Engineer Space Sciences Lab University of California, Berkeley EFW INST+SOC PDR

  2. 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) 15 to 27 degrees composite, normal operation (EFW-202) 47 degrees, Safe mode (SCRD 3.10.4.4) • 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) EFW INST+SOC PDR

  3. 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) • Instruments to survive without damage with -30 to +60 spacecraft boundary conditions. (EFW-79, EFW-80) • Comply with contamination control plan. APL document 7417-9007. (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 EFW INST+SOC PDR

  4. 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. EFW INST+SOC PDR

  5. 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. • Berkeley currently does not use them at this stage of integration but generates their own. • 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. EFW INST+SOC PDR

  6. Thermal Model OverviewInstruments and Boundary Spacecraft IDPU AXBs SPBs EFW INST+SOC PDR

  7. Thermal Model OverviewAXB -Stowed Sphere / Preamp (DAG 213) Rod to Stacer Hinge (DAG 213) Mounting Tube (M55J) Stacer (DAG 154) EFW INST+SOC PDR

  8. Thermal Model OverviewAXB -Deployed Sphere (DAG 213) Stacer (DAG154) DAD (AntiSun: Clear Alodine) (Sun: Clear Alodine / GeBk Tape mix) EFW INST+SOC PDR

  9. Thermal Model OverviewSPB & IDPU SPB - Deployed IDPU (Black Anodized) (GeBk Tape) (Clear Alodine) SPB - Stowed EFW INST+SOC PDR

  10. Optical Materials • Most properties tested, used, and correlated for the THEMIS mission • Properties submitted by APL and approved by the GSFC coatings committee July 07, 2008. EFW INST+SOC PDR

  11. Thermophysical Properties • No blankets currently required. • If blankets are needed at a later date the model will use e*=.05 and .01, Germanium Black Kapton outer layer. EFW INST+SOC PDR

  12. Interfaces IDPU • Conductively mounted to spacecraft side panel. • 6 #8 Bolts = 0.75 W/C each. • Radiative coupling to spacecraft interior, black anodized SPB • Conductively mounted to spacecraft side panel. • 4 #8 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 = 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. • Antisun Pre-Amp Sphere temperature can be super sensitive to the conduction through the Stacer-Rod hinge. Depends on stacer shadow length. Worst at SAA 20. EFW INST+SOC PDR

  13. Power, Heaters • Current power used in model • IDPU has a survival heater, set points -30 to -20 • SPB and AXB do not have any survival heaters • AXB currently has a place holder for a deployment heater. Need mature integrated spacecraft model to determine if heater is needed. EFW INST+SOC PDR

  14. Current Thermal Limits • Limits are produced in cooperation with mechanical and systems engineers. • Thermal predicts can drive mechanical and electrical design. or • Mechanical and electrical design can drive the thermal design. EFW INST+SOC PDR

  15. Limit Categories • Science Operation Limit • Limits placed on an operating instrument • Specifies the range of temperatures the instrument will be calibrated to • 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 EFW INST+SOC PDR

  16. General Case Sets • All current case sets run at a solar aspect angle of 20 degrees • Will scan attitudes and beta angles in the future to find the hottest and coldest attitudes. • These attitudes will be fed back to APL for inclusion in their nominal runs EFW INST+SOC PDR

  17. Current results • Basic science attitudes are within limits • Future runs will explore off nominal attitudes and full spacecraft model EFW INST+SOC PDR

  18. Status • Instrument thermal models are complete. • Geometry has been shipped to APL and included in the spacecraft geometry. • UCB boundary spacecraft model complete. • Preliminary check of science attitudes shows temperatures within limits. • Currently working to integrate the instrument network model with the spacecraft network model. • Need to incorporate APL heat rates into UCB analysis. • Need to produce high fidelity predicts from APL EFW INST+SOC PDR

More Related