HOW DO WE PREVENT SPACECRAFT FROM FAILING?
Henry B. Garrett, Ph.D.
September 2007

Often overlooked in the enthusiasm and pressure of building a spacecraft or space instrument is the reality that these systems are complex and can fail in many different and spectacular ways.  A major cause of failure is surprisingly the very space environment in which these systems operate.  Unfortunately, few engineers are aware of the many and subtle ways the environment can adversely affect their spacecraft until it is too late.  Typically, aside from the launch environment, thermal effects and radiation effects on parts are about all that are considered in design and test.  Management is normally unaware of key environmental concerns or openly hostile to proposals to evaluate the more exotic effects of potential concerns to their missions because of costs or possible latent damage.  The truth is that a simple, upfront evaluation of the likely effects of concern for a specific mission scenario can substantially reduce space environment effects.  A systematic approach to identifying, evaluating, and mitigating space environment effects would greatly facilitate this evaluation process.

The Van Allen belts, “solar flares”, and, maybe, meteor strikes are the environments we normally associate with spacecraft interactions—there are, however, many more potential environments of concern.  Table 1 lists a range of environments and interactions that we actually need to consider in a more thorough investigation of space environment effects.  Every mission design should begin with a review of a table like this to identify the possible environments and corresponding effects that need to be considered.  This step represents the beginning of a systematic approach to developing a mitigation strategy for the mission. 

To date there are few courses, books, or guidelines defining such a process.  The last few years, however, have shown an increasing realization of the need for such products.  In addition to the extensive ongoing efforts of the radiation effects community to address their part of the problem, several international conferences on other aspects of spacecraft interactions (spacecraft charging, meteoroids and debris, oxygen erosion, etc.) have better defined these concerns.  With computer programs/websites like NASA’s Environmental Workbench or the European on-line SPENVIS readily available, tools exist for quantitatively evaluating the interactions and environments mean.  Even small projects can now address these concerns in a meaningful manner.

The Launchspace course “Space Environment Requirements Engineering (The Design of Reliable Spacecraft)” merges these concerns, the tools to evaluate them, and a systematic process for mitigating them into a coherent picture.  Any project, design engineer, or scientist wanting to assure the reliability of their space systems should plan on taking this Launchspace course as the first step toward achieving their goal.  This course provides the key steps in developing an environmental definition, testing, and verification plan (called the Environmental Requirements Document or ERD) for a typical space mission.  Typically required for all space missions, the ERD and its interpretation are key elements to building a successful spacecraft or space instrument.  Garrett’s Launchspace course is specifically designed to address this critical document and its preparation (for a complete course description, see http://www.launchspace.com/2085.html).

Dr. Henry Berry Garrett, Col (USAFRet)

With over 30 years of professional experience, Dr. H. B. Garrett is a recognized international expert and consultant in space environments and their effects.  As a principle author of NASA’s Spacecraft Charging Guidelines, the popular book “Spacecraft Environment Interactions”, and of the official NASA jovian and saturnian radiation environments, he is well known in the spacecraft design community.  He is currently JPL’s Chief Technologist for the Office of Safety and Mission Success.

Launchspace Training
P.O. Box 34473
Bethesda, MD USA 20827-0473
Phone (Toll Free USA): (800) 960-0047 / Direct Phone: (301) 607-9040

Email Launchspace Training

Launchspace Training... our business is making your team more productive!

Web-Site developed and maintained by Kaplan Web-Designs