Computer program calculates spacecraft battery energy at specific times dictated by input sequence of recharge, discharge, and no activity phases. Recharge phases are assumed during times not specified, unless batteries are fully charged. Warnings are printed when energy falls below specified level. Program assumes two identical batteries

Abreu, A.

Slonski, J. P.

English

NASA Technical Reports Server

July 1971	 Brief 71-10250 
NASA TECH BRIEF 
NASA Pasadena Office 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the. Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D. f. 20546. 
Battery Simulation Program 
The problem: 
To devise a means of simulating spacecraft power 
subsystem batteries. 
The solution: 
A computer program which calculates battery 
energy at specific times dictated by an input sequence 
of recharge/discharge/no activity phases. Recharge 
phases are assumed during times not specified, unless 
the batteries are fully charged. Warnings are printed 
whenever battery energy falls below a specified 
level. The program assumes there are two identical 
batteries. 
How it's done: 
The battery simulation program accepts time and 
sequence data and forms a sequence of charge/ 
discharge/no activity phases which uses up all the 
time between specified start and stop times. All 
time is kept relative to the nearest periapsis passage. 
Hence, the program uses as parameters the orbital 
period and the number of the first periapsis pas-
sage. The charge states of the batteries are cal-
culated at the end of each phase. 
The sequence of program computations can be 
summarized as follows: 
1. Input miscellaneous data, occultation data, phase 
sequence data.
2. Interpolate occultation data to form a complete 
set of occultation phases over the period of 
interest. 
3. Merge phases, inserting recharge phases. 
4. Execute phases. 
The program has built-in recharge algorithms for 
various charge rates and temperatures. The utiliza-
tion of the two batteries in parallel is handled 
by a discharge algorithm, also built into the program. 
Notes: 
1. This program is written in FORTRAN V for use 
on the UNIVAC-1108 computer. 
2. Requests for further information may be directed 
to:
COSMIC 
Barrow Hall 
University of Georgia 
Athens, Georgia 30601 
Reference: B71-10250 
Patent status: 
No patent action is contemplated by NASA. 
Source: J P. Slonski and A. Abreu of
Jet Propulsion Laboratory 
under contract to
NASA Pasadena Office
(NPO-1 1580) 
Category 09 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned-rights.
https://ntrs.nasa.gov/search.jsp?R=19710000249 2020-03-17T02:19:59+00:00Z


Battery simulation program

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