Temperature ( C) Pressure ( bars) Jupiter Probes Venus Surface Exploration CNSR Europa Surface and Subsurface Titan In-Situ Temperature ( C) Radiation( MRad) Jupiter Probes Europa Surface and Subsurface Titan In-Situ Earth Venus Surface Exploration CNSR Pressure vs. Temperature Radiation vs. Temperature 500 Temperature, Pressure, and Radiation in Reference Missions

MissionAdvanced Thermal Control Technology Pressure Vessel Technology (100 bar) High Temperature (460 C) Components Low Temperature ( C) Components Corrosion Protection Technology Radiation Hard (> 5 Mrad) Components Radiation Shielding Technology (> 5 Mrad) Venus Surface Exploration and Sample Return XXXX Giant Planets Deep Probes XXX Comets Nucleus Sample Return XX Titan In-Situ XXX Europa Surface and Subsurface XXXX Challenge: All reference missions have to survive and operate in extreme temperature, pressure, and radiation environments. Summary of Reference Mission Technology Needs

Venus Dynamics Explorer Objective: Obtain Measurements to explain the general circulation of the Venus atmosphere The cloud-level atmosphere (~70 km) rotates about 60 times faster than the planet’s slowly- rotating surface (4 days vs 242 day period) –The mechanisms responsible for this superrotation have evaded theoretical explanation for >30 years

Venus Dynamics Explorer Approach: Long-lived balloons and Orbiter Network of 12 to 24 long-lived balloons Deployed between the surface and cloud tops at 3-4 latitudes (equatorial, mid, high) Time resolved measurements over ~1 week Discriminates eddies from mean flow VLBI tracking, p, T, solar/thermal radiation Orbiter Required for communications/ tracking UV and Near IR imaging spectrometers for tracking the upper, middle, and lower clouds S- and/or X-band radio science package to retrieve density profile at 34 km and 100 km

Zonal Wind (m/s) Altitude (km) Balloon Deployment Approach

Temperature (C) Technological Limits for Components Hard solders melt at ~ 400 C Soft solders melt at about ~180 C Connector problems start at ~150 C TFE Teflon degenerates at 370 C Silicon electronics can’t operate above 350 C Water 1 atm at 100 C Terrestrial Applications Geothermal Airplane Military Automotive Venus Jupiter Probes Enhanced Oil Recovery NASA Needs Geothermal Limit of commercial and military applications is currently about 350 C Oil Wells Gas Extreme high temperature/high pressure environments are unique to NASA missions High Temperature Limits of Conventional Components Magnets and actuators operational limit is ~ C

Power: Battery systems

Thermal Control Technology Needs for Decadal Missions MissionT/C DevicesApplicable Environment Comments Venus Surface Exploration and Sample Return Thermal insulation Thermal storage Thermal Switches Active cooling systems Active refrigeration Over 460 C 0 to 90 bar Missions lasting more than a few hours on surface will need active refrigeration system Giant Planets Deep Probes Thermal insulation, PCM storage, thermal switches, heat pipes C to +380 C 0.1 to 100 bar Temperature and pressure increase with depth in the atmosphere Comets Nucleus Sample Return Thermal insulation PCM thermal storage Thermal switches, Heat pipes Generally cold, below -140 C No environment Waste heat from RPS can be used for thermal control of avionics Titan In-Situ Explorer Thermal insulation PCM thermal storage Thermal switches, Heat pipes, active cooling loops -180 to -140 C 0.1 to 1.5 bar Long term operation on the surface requires radioisotope power source Europa Surface and Subsurface Thermal insulation, thermal storage, active cooling loops -160 C -`0.1 bar Waste heat from RPS can be used for thermal control of avionics All reference missions need advanced thermal control to survive and operate in extreme temperature and pressure.