NASA SBIR 02-1 Solicitation


PROPOSAL NUMBER:02- S2.04-9575 (For NASA Use Only - Chron: 022424 )
SUBTOPIC TITLE: Thermal Control and Management
PROPOSAL TITLE: Helium Loop Heat Pipe for Large Area Cryocooling

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
TTH Research
14625 Baltimore Avenue, #445
Laurel , MD   20743 - 3827
(301 ) 641 - 2954

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Triem Hoang
14625 Baltimore Avenue, #445
Laurel , MD   20743 - 3827
(301 ) 350 - 5092

To take full advantage of the space environment, Far Infrared (FIR)/Submillimeter (SMM) interferometers require cold mirrors (~4 K) and detectors (~0.1 K or colder). The collecting mirrors for the proposed FIR/SMM missions are large. The most difficult challenge will be the ~4K cryocooling of the entire telescope structure. Given long duration of the missions, stored cryogens do not present an attractive option. Hence, an active cryocooling system capable of removing 10-100mW at ~4K is absolutely essential for the mission success. The cryocooling system must provide continuous operation and not cause significant vibrations of the optical components. In addition, the cooling power will have to be distributed over large mirror surfaces.

To meet the challenging cryocooling requirements of the FIR/SMM missions mentioned above, TTH Research proposes the development of an advanced capillary pumped cryo-cooling transport system operating at ~4K. Despite the fact that the CPL/LHP technology has reached a high level of maturity, the proposed research effort will demand a host of technology innovations that do not exist at the present time. Among them are the use of Helium as the working fluid in CPLs/LHPs and cooling over large areas at cryogenic temperatures.

With a simple design and proven fabrication techniques, the large area LHP cooling loop is probably more adapted to the electronic cooling applications. In this case, it uses working fluids like water, methanol, or butane to transport and spread out the electronics waste heat over a larger area. Small diameter transport lines can be embedded in or even etched onto a Silicon wafer to form an integrated micro-chip and cooling system. A few examples of its potential usage are: heat spreaders for solid state transistors with medium to moderately high heat fluxes (20-50W/cm2) and heat transport devices embedded in printed circuit boards.

If the proposed He-LHP is successful as anticipated, then it will be the first-ever CPL or LHP to provide a passive cooling transport in the liquid Helium temperature range (~4K). But beyond that, the He-LHP will enable the exploitation of the FIR/SMM astronomy to explore the early universe, formation of galaxies, stars, and planets. FIR/SMM collecting mirrors are large. The entire telescope including the mirrors need to be cooled to ~4K to minimize background noise. The cryocooling system must be light in weight, integrate easily into the telescope, and not cause significant vibrations to the optical components. Furthermore, it will likely have to be flexible and deployable. The He-LHP will meet all aforementioned requirements offering a robust passive ~4K cryocooling transport over large areas.

Form Printed on 09-05-02 10:10