Mr. David C. Bugby Profile

David C. Bugby

at Northrop Grumman Systems Corp

SPIE Involvement:

Author

Publications (2)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 18 August 2005 Paper

Cryogenic diode heat pipe system for cryocooler redundancy

David Bugby, Jessica Garzon, Matthew Beres, Charles Stouffer, Douglas Mehoke, Melissa Wirzburger

Proceedings Volume 5904, 59040Z (2005) https://doi.org/10.1117/12.617242

KEYWORDS: Cryocoolers, Mars Reconnaissance Orbiter, Liquids, Switching, Cryogenics, Sensors, Methane, Diodes, Aluminum, Head

Read Abstract +

This paper describes the design, manufacturing, modeling, and testing of a methane cryogenic diode heat pipe (CDHP) thermal switching system for the CRISM instrument onboard the NASA/JPL Mars Reconnaissance Orbiter. The purpose of the CDHP system is to enable three 1-year cryocoolers to provide 2 years of cooling to the 100 K CRISM sensor while minimizing the parasitic heat input from the two OFF (redundant) cryocoolers. Without the CDHP system, the parasitic heat input from the two OFF cryocoolers would prevent the CRISM sensor from being cooled to an acceptably low operating temperature. To provide sufficient structural support for launch with low parasitic heat input, the three methane CDHPs were supported by small diameter Kevlar tension cables attached to a shoebox-shaped cold shroud that enveloped the assembly. The cold shroud -- thermally coupled by a flexible link to the (cryoradiator cooled) cold side of the instrument housing -- was suspended from the warm side of the instrument housing by a second set of Kevlar cables, creating a dual-nested Kevlar cable thermal isolation/structural support system similar to that flown on the CRYOTSU flight experiment on STS-95. To accurately test the thermal switching system, a novel laboratory set-up was utilized involving three parallel heat metering cryocooler simulators (Q-meters). Numerous test runs were carried out to evaluate the impact of various system operating parameters. The parasitic heat leak predictions corresponded very closely to the measured data. The paper describes the effort from concept development through test data analysis.

Proceedings Article | 18 August 2005 Paper

Advanced cryogenic thermal switches for JWST

David Bugby, Matthew Beres, Charles Stouffer, Jose Rodriguez

Proceedings Volume 5904, 59040F (2005) https://doi.org/10.1117/12.617676

KEYWORDS: Switches, James Webb Space Telescope, Aluminum, Cryogenics, Switching, Thermal modeling, Data modeling, Solids, Resistance, Gold

Read Abstract +

This paper describes two cryogenic thermal switches (CTSWs) under development for instruments on the James Webb Space Telescope (JWST). The first thermal switch was designed to extend the life of the solid H2 dewar for the 6 K Mid Infrared Instrument (MIRI) while the second thermal switch is needed for contamination and over-temperature control of three 35 K instruments on the Integrated Science Instrument Module (ISIM). In both cases, differential thermal expansion (DTE) between two materials having differing CTE values is the process that underpins the thermal switching. The patented DTE-CTSW design utilizes two metallic end-pieces, one cup-shaped and the other disc-shaped (both MIRI end-pieces are Al while ISIM uses an Al/Invar cup and an Al disc), joined by an axially centered Ultem rod, which creates a narrow, flat gap between the cup (rim) and disc. A heater is bonded to the rod center. Upon cooling one or both end-pieces, the rod contracts relative to the end-pieces and the gap closes, turning the CTSW ON. When the rod heater is turned on, the rod expands relative to the end-pieces and the gap opens, turning the CTSW OFF. During testing from 6-35 K, ON conductances of 0.3-12 W/K and OFF resistances greater than 2500 K/W were measured. Of particular importance at 6 K was the Al oxide layer, which was found to significantly decrease DTE-CTSW ON conductance when the mating surfaces were bare Al. When the mating surfaces were gold-plated, the adverse impact of the oxide layer was mitigated. This paper will describe both efforts from design through model correlation.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years