Influence of the Internal Energy Model on DSMC Flow Results for Rarefied Spacecraft Plumes
Abstract
In low Earth orbit, energetic collisions between molecules from spacecraft emissions and atmosphere are observed to produce a luminescent interaction layer [1, 2]. These collisions deposit a substantial amount of energy into the internal modes of the molecules. The rate at which this energy is deposited and the distribution of that energy among translational, rotational, and vibrational degrees of freedom govern many properties of the interaction layer, including its temperature distribution, shape, and spectral radiance. Direct simulation Monte Carlo (DSMC) models [3] are among the important tools for predicting the interactions between the atmosphere and spacecraft surfaces or gases emitted by spacecraft in low Earth orbit [4?6]. Recent experimentally-determined vibrational transition chemistry (such as for O + CO [7]) now enables use of an internal energy model with explicit transition cross-sections between ground and explicitly-enumerated quantized excited vibrational states which we will explore in this work. The SOCRATES1 and SOCRATES-P2 codes [8?10] are DSMC codes that are specialized for computing spacecraft contamination flow fields [11], radiative byproducts of space vehicle effluents and exhausts [12?14] and their spectra, and for use in analysis of molecular beams [15, 16].
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2010
- Accession Number
- ADA527310
Entities
People
- Jason A. Cline