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Rivera, Jose G.

Publications and source records attributed to Rivera, Jose G..

Instrument Thermal Management for Lunar Night Survival without Radioisotopes

This paper summarizes the technology development progress on two JPL projects focused on developing thermal designs/technologies that enable lunar instrument overnight survival without radioisotopes. Through an internal project known as ARTEMIS, JPL has developed lunar night survivable designs for magnetometer, seismometer, and IR spectrometer science payloads (SPs). These designs incorporate four hyper-isolative thermal management features under development on the NASA GCD-funded PALETTE project: (a) a dual enclosure system with high strength, low k tension cable (TC) supports and a variable conductance thermal link (VCTL) composed of a reverse-operation DTE thermal switch (ROD-TSW) in series with a miniaturized loop heat pipe (mini-LHP); (b) a parabolic reflector radiator (PRR) for low-to-mid latitude lunar sites; (c) ultra-low e* “spacerless” MLI, in which individual layers are hung from the TC supports; and (d) ultra-low G thermal isolators made with polymeric material or polymer/TC assemblies. Each instrument design incorporates solar panels, batteries, telecom, C&DH, and other features necessary for self-sufficient, extended-duration operation on the lunar surface. This paper will provide an overview of the ARTEMIS and PALETTE projects and provide a top-level description of the instrument thermal management approach.

Lin, Ying↗

Extended Stroke and Miniaturized Reverse-Operation DTE Thermal Switches

This paper describes two advanced thermal switches under development that are offshoots of the recently flight-qualified 2500:1 reverse-operation differential thermal expansion (DTE) thermal switch (ROD-TSW). The first is the extended stroke ROD-TSW (ES-ROD-TSW) while the second is the miniaturized ROD-TSW (mini-ROD-TSW). Each employs multiple diametrically nested DTE stages in contrast to the single-stage ROD-TSW. The ES-ROD-TSW employs two stages and a negative CTE material known as Allvar and its main purpose is to extend its stroke for use in non-vacuum planetary environments. The mini-ROD-TSW employs four stages to miniaturize its size for use in compact lunar instruments and rovers. The ES-ROD-TSW was TVAC tested at JPL and its ON/OFF ratio is 13000:1 based on a measured ON conductance of 6.89 W/K and a calculated OFF conductance of 0.00053 W/K. The mini-ROD-TSW is targeted to have an ON conductance of 1.5 W/K and an OFF conductance of 0.0015 W/K, both verified by analysis. Test verification of the mini-ROD-TSW remains to be carried out. The paper will provide design/performance details of each device.

Farmer, Jeffery T.↗

High Performance Thermal Switch for Lunar and Planetary Surface Extreme Environments

This paper describes a high performance thermal switch for lunar/planetary extreme environments. This device has been given the name Reverse-Operation DTE Thermal Switch (or ROD-TSW). Two different prototypes were designed, built, and tested. Their basis of operation is the mating/de-mating of parallel flat metal surfaces driven by the differential thermal expansion (DTE) between mid-to-high CTE metal/polymer or metal-only end-pieces and a low CTE, low thermal conductivity (k) metal/polymer support rod. The requirements were to be fully ON above 300 K and fully OFF below 260 K. A series of four tests were carried out to verify/qualify the prototypes. In the first (non-vacuum) test, the thermal switches were cooled with freeze-spray and the non-conductive rod in the OFF thermal path allowed electrical resistance to confirm the 273 K as-designed ON/OFF actuation temperature. In the second (vacuum) test, a calibrated Q-meter was used, which indicated 5 W/K ON, 0.002 W/K OFF conductance (2500:1 ON/OFF ratio). To increase readiness to TRL6, a vibration test with pre/post thermal cycling followed by a 36-day test in a relevant environment were also carried out. This paper describes the development program and on-going related work at JPL.

Bugby, David C.↗