ASTM E491-73 (2020) PDF

Full title and description

Standard Practice for Solar Simulation for Thermal Balance Testing of Spacecraft — ASTM E491-73 is a practice that provides guidance for performing thermal balance tests of spacecraft and spacecraft components using solar simulation to reproduce the space radiation (solar) environment for thermal and systems‑integration testing. This designation is commonly shown as E491 − 73 (reapproved in later years).

Abstract

This practice describes the objectives, test arrangements, and performance characteristics required of solar simulators used to perform thermal‑balance testing of space vehicles and subsystems. It explains the intended test environment, limits of applicability (for example, it does not cover launch or reentry phases, lander surface tests, or radiation‑damage tests), and provides guidance to ensure adequate simulation of the radiation environment for thermal testing and systems‑integration evaluations.

General information

• Status: Historical / Withdrawn (reapproved historically; see notes).
• Publication date: Original adoption 1973; reapproval and editions issued subsequently (notably reapproved 2010 edition published Mar 31, 2010); document metadata shows a last‑updated record Dec 10, 2020.
• Publisher: ASTM International.
• ICS / categories: 49.140 — Space systems and operations (space simulation / thermal testing).
• Edition / version: Designation commonly cited as E491 − 73 with later reapprovals (example: E491‑73 (Reapproved 2010) / E0491‑73R15 in publisher records).
• Number of pages: 34 pages (typical for the reapproved edition).

Scope

The practice applies where solar simulation is the chosen method for thermal balance testing of spacecraft and components. It covers how to reproduce the solar irradiance environment in vacuum chamber tests to evaluate thermal control designs and system interactions. It explicitly excludes tests for launch/reentry environments, planetary lander surface conditions, degradation studies of thermal coatings, certain sensor tests (for example sun sensors), tests for outgassing or bulk material thermal properties, and energy‑conversion device qualification; users are directed to other specialized standards for those topics.

Key topics and requirements

• Definition of solar simulator performance characteristics needed for thermal‑balance tests (irradiance level, spectral content, collimation/beam geometry, uniformity, and stability).
• Guidance on test chamber arrangements and test environment control to reproduce space radiation and thermal conditions.
• Limits of applicability and nonapplicability (what types of tests are not covered).
• Reference to related terminology and measurement standards used in space simulation and irradiance characterization.
• Acceptance criteria and recommended practices for ensuring adequate simulation for thermal‑balance and systems‑integration testing.

Typical use and users

Used by spacecraft thermal engineers, test‑facility managers, environmental test laboratories, and systems engineers responsible for pre‑launch thermal balance and systems‑integration verification. Typical applications include thermal vacuum testing of satellites, subsystem thermal qualification using solar simulators, and support for flight acceptance testing where accurate solar irradiance simulation is required.

Related standards

ASTM E491 is connected to other ASTM standards for solar simulation, solar spectral data, and space‑environment testing. Notable related documents include ASTM E927 (classification of solar simulators for PV testing), ASTM E490 (solar constant and zero‑air‑mass spectral irradiance tables), ASTM E948 (electrical performance of photovoltaic cells under simulated sunlight), ASTM E349 (terminology relating to space simulation), and other space‑testing practices and test methods referenced within the practice.

Keywords

solar simulation, thermal balance testing, spacecraft, solar irradiance, collimation, spectral match, vacuum chamber, space simulation, thermal vacuum test, ASTME491.

FAQ

Q: What is this standard?

A: ASTM E491‑73 is a standard practice titled "Standard Practice for Solar Simulation for Thermal Balance Testing of Spacecraft" that provides guidance for using solar simulators in thermal‑balance and systems‑integration tests of spacecraft.

Q: What does it cover?

A: It covers solar simulator performance characteristics, test arrangements in thermal‑vacuum chambers, recommended test practices to reproduce solar radiation for thermal balance testing, and the limits of applicability (listing test types it does not address).

Q: Who typically uses it?

A: Spacecraft thermal engineers, environmental test labs, systems‑integration teams, and test‑chamber facilities that perform thermal vacuum and solar simulation testing for satellites and space systems.

Q: Is it current or superseded?

A: The standard has a historical/retracted status in some public catalogs and has appeared as a reapproved document (examples: E491‑73 reapproved editions such as the 2010 reapproval). Publisher records show updates/editions and a last‑updated metadata record in 2020; users should consult ASTM International for the authoritative current status and any active replacements or revisions.

Q: Is it part of a series?

A: E491 sits within ASTM Committee E21 work on Space Simulation and is cross‑referenced with other ASTM space and solar‑simulation standards (for example E927, E490, E948, and E349). It is one practice among several that address aspects of solar simulation, solar spectral data, and space environment testing.

Q: What are the key keywords?

A: Solar simulator, thermal balance, spacecraft testing, irradiance, spectral match, collimation, vacuum chamber, space simulation.