An overview of studies conducted to establish the requirements for advanced subsystem analytical tools is presented. Modifications are defined for updating current computer programs used to analyze environmental control, life support, and electric power supply systems so that consumables for future advanced spacecraft may be managed

Daly, J. K.

Torian, J. G.

English

NASA Technical Reports Server

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https://ntrs.nasa.gov/search.jsp?R=19790008736 2020-03-22T01:09:49+00:00Z
26821-H026-RO-00
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FORMULATION OF ADVANCED CONSUMABLES
i&jo	 MANAGEMENT MODELS
JANUARY 1979	 CONTRACT NO. NAS9-14264
(NASA
	
-16 0095)
	 FORMUZATTCN OF ADVANC
CO ySUMABLES MANAGEMENT MODELS: EXECUTIVE
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26821-H026-RO-00
FORMULATION OF ADVANCED CONSUMABLES
MANAGEMENT MODELS
!ANUARY 1979	 CONTRACT NO, NAS9-14264
EXECUTIVE SUMMARY
Prepared by
J. K. Daly
J. G. Torian
Operational Systems Section
TRW
DEFEAdf AAO SIMCE SYSTEMS GROUP 	 ``
CONTENTS
Page
1 .0	 INTRODUCTION  .
	
.	 .	 .	 .	 . .	 .	 .	 .	 .	 . . . .	 .	 .	 .	 .	 .	 .	 .	 .	 .	 1-1
2.0 FORMULATION OF INTERACTIVE SUBSYSTEM MODELS
	
. . . . . . . .	 2-1
2.1 ENVIRONMENTAL CONTROL AND LIFE SLIPPOR;
	
ANALYSIS PROGRAM	 . . . . . . . . . . . . . . . . . . .
	 2-1
	
2.2 ELECTRICAL POWER SYSTEM PROGRAM . . . . . . . . . . . . 	 2-7
1
i
1.0 INTRUUUCTION
Current consumables management techniques are support ed by computer pro-
grams which provide consumables analysis in support of Spca
 Transportation
System (STS) preoperational flight programs. The techniques are also sup-
ported by operational period computer programs currently under development
for space vehicles such as STS and other advanced spacecraft programs. These
latter programs provide consumables management techniques which relieve
skilled personnel from the routine processing associated with repetitive
spacecraft mission planning and operational functions. This allows concen-
tration on detailed trade studies and mission assessment in support of ad-
vanced missions and spacecraft. Current subsystem analysis tools used for
trade studies and mission assessment are out of date with respect to com-
puter application and flexibility to model the more advanced spacecraft
subsystems. These reports present the results of a study to establish the
requirements for advanced subsystem analytical tools and define the modi-
fications and updating of current computer programs that will satisfy the
requirements for future space programs.
The final report on the study to formulate advanced consumables manage-
ment models is presented in two parts - an Executive Summary and a Final
Technical Report.
This Executive Summary presents an overview of the study results.
The Final Technical Report presents the software design specifications
for development of Environmental Control and Life Support System (ECLSS) and
Electrical Power System (EPS) interactive computer programs.
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2.0 FORMULATION OF INTERACTIVE SUBSYSTEM MODELS
Continued effective flight design support in the high frequency flight
environment of Space Transportation System (STS) requires the updating of
cur.°ent analytical techniques. The objective of the improved techniques is
to provide rapid model development, as well as performance analysis for a
variety of subsystem configurations. The modeling and performance analysis
of the ECLSS and EPS are required to assess both nominal and contingency
flight plans. The development specifications for such models are presented
in the Final TecKoical Report. An overview of these models and their char-
acteristics follows.
2.1 ENVIRONMENTAL CONTROL .;ND LIFE SUPPORT ANALYSIS PROGRAM
The objectives of ECLSS performance evaluations are best satisfied by
the application of an interactive computer program with which the user
accesses a library of routines simulating the performance of various com-
ponents and functions common to ECLSS. These routines are assembled with a
driver routine (MAIN) to simulate the particular ECLSS under consideration.
The assembled program is then loaded and executed to produce the transient
performance parameters of the ECLSS under prescribed boundary conditions.
The assembly procedures for such a program are shown in Figure 1. The
master library of routines is extracted from a secure file. The user has
th-^ option to enter a MAIN routine (as for initial development of an ECLSS
model). or extract a particular MAIN from his individual library (as for
update/LJit and/or additional studies with a previously developed ECLSS
model). The extracted MAIN may be altered as part of he update/edit pro-
cess. The program is then MAP'ed and the MAIN may be stored in the user's
file for future use. The particular ECLSS program is then ready for execu-
tion.
The execution procedure including a variety of input/output options is
shown in Figure 2. The component characteristic data and initial conditions
may be read in from restart data stored previously or entered directly. If
2-1
Figure 1. ECLSS Program Assembly Procedures
2-2
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Figure 2, ECLSS Program Execution Procedure
2-3
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Figure 2. ECLSS Program Execution Procedure (Continued)
2-4
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Figure 2, ECLSS P ,ogram Execution Procedure (Concluded)
the user desires, Vie system will output a schema,ic of the LCLSS modeled.
The user has the option :r select par t icular nodes (component locations) to
be inc idO in tabular cutput* or the systern will default to include all
output for tabular nodes defined in the model. if plots are desired, the
user sifi:ply defines the particular parameters to be plotted. Restart data
may be stored for future use. Up to this point the program is executed in
an interactive mode which is mandatory as noted in Figure 2. The program
then transfers to a second stage of execution.
The second stage of execution is passive in the sense the data are pro-
cessed with no interaction on the part of the user. The processing accesses
EPS data and/or trajectory data automatically, if required. The data can be
accessed from tape, secure files, or interface to other progrd ►ns resident in
the syste.^. This stage of execution produces the tabular and plot data,
This stage is optional in that the user may execute and witness the tabulai-
data as they are produced, c.r exit at this point. Exit may be desir p;; io a
case where the user desired only tc update the model and review the schematic.
Exit may also be desired so that this stage of execution can be performed
off line in a batch-mode rather than interactively.
A second interactive execution is available which allows the user to
extract the plot data just created or a previously ;treated plot data for dis-
play on the terminal. The execution is interactive with the user sinnNiy
specifying which plots are to be displayed.
Specifications for the ECLSS program have been developed at the detail
design level with respect to modification of an existing batch mode program.
The Fortran Environmental Analysis Routines (FEAR) of Reference 1 are the
subject batch mode program. De ,elopment of this interactive program requires
familiarity with ECLSS analysis, the FEAR program and Reference 1. However,
an Appendix summarizing -,.he characteristics of the FEAR program is iicluded
in the Final Technical Report. This Appendix is provided as a reference for
the reader with a general interest in modifying batch mode programs to form
interactive programs, rather than the specific modification of FEAR.
*Tabular output may be stored for input to, or directly interfaced to other
resident programs requiring these parameters.
2-6
A pilot model of the interactive model was developed and used as an aid
in establishing these specifications.	 Illustrative interactive displays gen-
erated by the pilot model are used as examples throughout the specification
text.
2.2 ELECTRICAL POWER SYSTEM PROGRAM
The objectives of EPS analysis are best satisfied by an interactive pro-
gram similar in structure to the ECLSS program of the previous section.
However. EPS models, in general, do not encompass as wide a variety of com-
ponents and configurations as do ECLSS models. Accordingly, it is not nec-
essary that the user he required to develop and supply the driver (MAIN).
The EPS network description, component characteristic &'.a, and boundary
condition are entered interactively during execution.
The execution procedure for an interactive EPS p, •ogram is shown in
Figure 3.
The user interface with respect to network description, component
characteristics definition and boundary condition data input, as well as
internal processing of the program have been developed and included in the
specification. The EPS program specifications are at the preliminary design
level. The specifications in the Final Technical Report assume the reader
is familiar with EPS analysis techniques. Emphasis is on top-down struc-
turing in the development of an interactive program.
2-7
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Figure 3. EPS Program Execution Procedure
2-8
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Figure 3, EPS Program Execution Procedure (Continued)
2-9
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Figure 3. EPS Program Execution Procedure (Concluded)
2-10


Formulation of advanced consumables management models: Executive summary

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