Value chain · CLM-0881
In plain terms
Above roughly 55 volts, a spacecraft power system in low orbit can charge enough to arc and damage itself. NASA has a design standard for it, and the standard says the exact thresholds are not well known and have to be tested for.
The claim as recorded
NASA's LEO spacecraft charging design standard rests on the finding that power systems operating above about 55 volts may charge sufficiently in low Earth orbit to cause destructive arcing, and the paper describing it states that many of the arcing thresholds are poorly known and must be established by testing rather than by calculation.
Evidence behind this: Government-authored paper read directly in the held file. NOT T1: it describes NASA-STD-4005, it is not the standard.
Scope and limits
THIS IS A LOW EARTH ORBIT CONSTRAINT AND EVERY SPS DESIGN IN THE REGISTER IS GEOSTATIONARY. GEO charging is a different plasma regime with a different mechanism, and nothing here establishes a GEO threshold or that this one transfers. IT MAY NOT BE USED TO ARGUE THAT A 5 kV OR 40 kV GEO BUS ARCS. What it does establish is that bus voltage is a plasma-interaction constraint and not only a conductor-mass trade, which no record in the register previously stated. The source itself says the thresholds are poorly known.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
Read in the held file: "Power systems with voltages higher than about 55 volts may charge in Low Earth Orbit (LEO) enough to cause destructive arcing." And: "Many of the thresholds for arcing are poorly known, and if the strategy to prevent arcing is to keep voltages lower than the appropriate threshold, testing must be used to determine those thresholds."
Basis: LEO plasma environment
Related records
- Answers question
- QST-043 not published in this release
Cite this
energyaperture.com/c/clm-0881
CLM-0881, Energy Aperture, as of 2006.