Accession Number:

ADA505618

Title:

Particulate Infiltration into a Simulated Space Telescope

Descriptive Note:

Corporate Author:

AEROSPACE CORP EL SEGUNDO CA

Personal Author(s):

• Liu, De-Ling
• Luey, Kenneth T.

Report Date:

2008-12-31

Pagination or Media Count:

24.0

Abstract:

To understand the dynamics of airborne particulate intrusion into a space telescope, a mechanistic model based on mass balance was developed to predict the extent to which ambient particles penetrate through vent holes and enter the interiors after the purge is off. This work describes the mathematical modeling analysis, supplementing with results from laboratory measurements using a cylindrical chamber as a simulated space telescope. It was found that the characteristic time for airborne particles to reach a saturation level, after the purge is off, can be characterized by the air-exchange rate and particle deposition rate inside the confined space volume. The air-exchange rate, measured using a tracer gas technique, is associated with the natural convection and air flow turbulence intensity adjacent to the chamber. During the purge outage, the steady-state airborne particle concentration inside the space telescope is governed by the ambient particle concentration, air-exchange rate, and particle deposition rate.

Descriptors:

• *SPACE SYSTEMS
• *PARTICULATES
• *TELESCOPES
• *INTRUSION
• DYNAMICS
• MASS
• AIRBORNE
• AIR FLOW
• INTENSITY
• RATES
• CONVECTION
• TURBULENCE
• SATURATION
• DEPOSITION
• PARTICLES
• INFILTRATION(FLUIDS)
• CYLINDRICAL BODIES
• HOLES(OPENINGS)
• MATHEMATICAL ANALYSIS
• BALANCE
• LABORATORY PROCEDURES
• CHAMBERS
• VENTS
• TRACE GASES
• VOLUME
• MEASUREMENT
• CONFINED ENVIRONMENTS
• MATHEMATICAL MODELS
• SIMULATION

Subject Categories:

• Meteorology
• Optical Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE