NASA Technical Reports Server (NTRS) 19730004171: Orbiting propellant depot safety. Volume 1: Management summary report

AEROSPACE ' REPORT NO.
ATR-7l(7233)-3. VOL I

$ 3, rs

Final Report

Orbiting Propellant Depot Safety

Volume I: Management Summary Report

Prepared for OFFICE OF MANNED SPACE FLIGHT
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

Washington, D. C,

Contract No. NASW-2129

Systems Engineering Operations

THE AEROSPACE CORPORATION

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national technical
information service

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FINAL REPORT

Aerospace Report No.
ATR-7i(72^3)-3, Vol. I

ORBITING PROPELLANT DEPOT SAFETY
Volume I: Management Summary Report

Prepared by

Advanced Vehicle Systems Directorate
Systems Planning Division

20 September 1971

Systems Engineering Operations
THE AEROSPACE CORPORATION
El Segundo, California

Prepared for

Office of Manned Space Flight
National Aeronautics and Space Administration
Washington, D. C.

Contract No. NASW-2129

Aerospace Report No.
ATR-7i(7223}-3, Vol. X

FINAL REPORT

ORBITING PROPELLANT DEPOT SAFETY
Volume I: Management Summary Report

Prepared by Advanced Vehicle Systems Directorate

R7 R. Wolfe, jStudy Manager
Director

Operations Office
Advanced Vehicle Systems
Directorate

Systems Planning Division

Approved by

S. M. Tefanant
Assistant General Manager
Systems Planning Division
Systems Engineering Operations

The information herein is tentative and is subject to modification. Initial
distribution of this document is confined to persons and organizations imme-
diately concerned with the subject matter.

11

PREFACE

This study was initiated as Subtask 3, Orbiting Propellant Depot Safety Study
of NASA Study C-II, Advanced Missions Safety Studies. Other studies in this
series are: (i) Subtask 1, TNT Equivalency Study, Aerospace Report No.
ATR-71(7233)-4; and (ii) Subtask 2, Safety Analysis of Parallel versus Series
Propellant Loading of the Space Shuttle, Aerospace Report No. ATR-71 (7233)- 1 .

The study was supported by NASA Headquarters and managed by the Advanced
Missions Office of the Office of Manned Space Flight, Mr. Herbert Schaefer,
the Study Monitor, provided guidance and counsel that significantly aided this
effort.

Study resolts are presented in three volumes; these volumes are summarized
as follows:

Volume It Management Summary Report presents a brief, concise
review of the study content and summarizes the principal conclusions
and recommendations.

Volume II: Technical Discussion provides a discussion of the
available test data and the data analysis. Details of an analysis
of possible vehicle static failure modes and an assessment of
their explosive potentials are included. Design and procedural
criteria are suggested to minimize the occurrence of an explosive
failure .

Volume III: Appendices contains supporting analyses and backup
material.

iii

ACKNOWLEDGEMENT

The principal participants of The Aerospace Corporation in this study were:

M. Donabedian

R. P.

Toutant

R. R.

Wolfe

H * H * Y o s hi ka wa

Semimodular/ Modular

Concept Development and Analysis

Docking /Transfer Interface
Concept Development and Analysis

Study Manager and Director,
Operations Office

Advanced Vehicle Systems Directorate

Integral Concept Development and
Analysis

IV

CONTENTS

1. INTRODUCTION 1

2. STUDY OBJECTIVE AND CONSTRAINTS 3

2. 1 Objectives 3

2.2 Constraints 3

3. RELATION TO OTHER NASA EFFORTS 5

4. METHOD OF APPROACH 7

5. RESULTS 9

5. 1 General 9

5. 2 Concepts 9

5. 2, i Integral 9

5.2.2 Semimodular 9

5.2.3 Modular 12

5. 3 Hazard Analysis 12

6. CONCLUSIONS AND RECOMMENDATIONS 15

6.1 Conclusions 15

6. 2 Recommendations 15

FIGURE

1. Semimodular Concept 11

TABLES

1. Orbiting Propellants Depot Concepts 10

2. Typical Modular Resupply Hazards (common to all

concepts) 13

3. Typical Propellant Transfer Hazards (common to

integral and semimodular concepts 14

v

1. INTRODUCTION

Under consideration, are orbital missions that require the use of vehicles
other than Space Shuttles, e. g. , a cislunar shuttle, that is either chemically
or nuclear propelled, space tugs functioning as shuttles which can service
orbiting payloads or vehicles. Such vehicles may be spaced-based. In this
operational mode, the vehicles would be stationed in a low earth orbit from
which they would initiate and terminate flights. The only time these vehicles
might return to earth would be for major maintenance.

The flight frequency of these vehicles indicates that large quantities of pro-
pellants will have to be delivered to them in orbit. Orbiting propellant depots,
in both geocentric and selenocentric orbits, are being considered as candidate
methods of making the required propellants readily available. Therefore, as
an initial part of the evaluation of this concept, an assessment of the potential
safety hazards associated with the operation of such a depot (OPD) is desirable

1

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2. STUDY OBJECTIVE AND CONSTRAINTS
2. 1 OBJECTIVES

The objective of this study was to provide safety guidelines and requirements
for the operation of an Orbiting Propellant Depot.

2. 2 CONSTRAINTS

Because conceptual configurations of the OPD were not to be, and have not
been, developed in depth, this study was limited to a top level qualitative
safety analysis of the gross depot requirements. However, certain orbiting
vehicle (OV) concepts had to be taken into consideration, such as a Space
Shuttle that would be launched from earth by a booster stage and carry
orbiting vehicle(s) such as (a) change-of-plane shuttles, (b) tugs, or (c) other
vehicle which might be maintained and/or refurbished in (geocentric) orbit
or might be returned to earth for same.

3

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3, RELATION TO OTHER NASA EFFORTS

This study provided safety- related criteria which will be useful in assessing
configuration proposals for OPD, The criteria will provide safety guidelines
and requirement inputs for future system design tasks and a baseline against
which design progress can be weighed relative to safety.

5

PBECEDB3G

PAGE

BkANX

4. METHOD OF APPROACH

The general plan followed in this study included:

a. Development of conceptual orbiting propellants depot
configurations,

b. Assessment and comparison of conceptual gross levels
of safety.

c. Establishment of recommendations as to safety requirements
and criteria for normal and emergency operations.

7

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preceding page h

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5, RESULTS

5* 1 GENERAL

This study is applicable to an Orbiting Propellants Depot (OPD) located in
geocentric or selenocentric orbits. Since there was no firm design approach,
three configurations were examined in an effort to bracket the design concepts.
In the three concepts studied, the OPD was posited as being unmanned and
the user or resupply vehicle as manned.

Propellants for the OPD would be delivered by a space shuttle to an OPD in
geocentric orbit; however, an additional flight would be required to deliver
propellants to an OPD in a selenocentric orbit,

5, 2 CONCEPTS

The distinguishing features of the three concepts are discussed in the following
paragraphs, A comparison of the concepts, indicating advantages and dis-
advantages, is given in Table 1.

5. 2, 1 Integral

In the integral concept, the propellant storage tanks form a permanent part
of the primary structure of the OPD, All propellants received or dispensed
by the OPD must utilize the OPD propellant transfer subsystem,

5, 2. 2 Semimodular

In the semimodular concept, as shown in Fig, 1, a central core contains all
subsystems required for operation of the OPD, Arranged around the core is
a series of docking ports which accept modularized propellant storage tanks
for resupply of the OPD; empty tanks are returned to earth by a resupply OV
and are recycled* The concept is similar to the integral concept with respect
to the dispensing of the propellants.

9

Preceding page blank

Table 1. Orbiting Propellant Depot Concepts

Di s advantages

1 . Two docking
sequences required
per resupply

2, Requires propellant
flow plus tank
exchange

Propellant transfer
line vulnerable to
unstable OPD

1. Two docking se-
quences per resupply

2. Complex manifolding
system required

1. Two docking se-
quences per resupply

2. Requires more
critical maneuver
during tank exchange

1. Improper boom
operation can cause
tank/OV damage

2. Hard dock required

3. OPD unstable during
tank movement

Advantages

1. OV separate during
propellant operation

2. OV not affected by
OPD instability

1. Eliminates hard
docking of OV with
OPD

2. Unstable OPD oper-
ation has minimal
impact on OV

1. No propellant flow
during resupply

2. No propellant phase
control required
during resupply

1, No propellant flow
required

2, No propellant phase
control required

1. No propellant flow
required

2. Single docking
sequence

Concept

Receiver

Vehicle

Resupply

Propellant

flow

Propellant

flow

Propellant

flow

Modular

Modular

OPD

Resupply

Technique

Modular

Fuel

transfer

probe

Modular

Modular

Modular with
OPD- mounted
boom

u

1

u

<3

2

Q

CU

u

bo

<u

tj

0

a -g

p -u

O

S

to o

&

■ H
£

2

<D

to

10

CHARACTERISTICS

i MODULAR OPD WITH CENTRAL MANIFOLDING AND SUBSYSTEMS

ii MODULAR RESUPPLY WITH INTEGRAL TRANSFER TO USER VEHICLE

Figure 1. Semimodular Concept

11

5. 2. 3

Modular

The modular concept is similar to the semimodular concept both in configuration
and method of resupply, i. e, , a central core to which the propellant modules
are docked {Fig. 1). It differs from the integral and semimodular concepts
in that no fluid flow is required to dispense propellants. The user OV being
serviced exchanges its empty propellant tanks for full tanks. The empty tanks
would be stored at the OPD until they were returned to earth by a resupply
OV for recycle.

5. 3 HAZARD ANALYSIS

The analysis considers operational sequences in which personnel are subjected
to safety hazards. These events could occur in two main operational phases:

a. OPD resupply

b. Propellant transfer from the OPD to a user OV

Top-level failure mode and effect analyses were performed for the major
events occurring in these phases. NASA hazard categories, ranging from
catastrophic to negligible, were used to grossly classify those of the study.

As each hazard was evaluated, preventive and remedial criteria were
developed. Preventive criteria are meant to be utilized as inputs to design
and operations documents to prevent or minimize the possible occurrence(s)
of the failure(s). Remedial criteria suggest contingency or backout procedures
to be employed after a failure has occurred. Tables 2 and 3 contain typical
examples of hazard analyses.

12

Table 2, Typical Modular Resupply Hazards (common to all concepts)

13

14

6. CONCLUSIONS AND RECOMMENDATIONS

6. 1 CONCLUSIONS

1, The semimodular depot concept appears to be the safest
and operationally the most flexible of the configurations
analyzed,

2, A completely open- structured depot is desirable, i, e, , no
pressurized areas other than the storage tanks; where
enclosed areas cannot be avoided, the capability to purge
these areas is desirable.

3, Coaxial propellant transfer lines or parallel loading of
propellants is not recommended.

4, Positive identification of LO^/Lf^ transfer interfaces is
required,

5, Unique fittings should be used at the LO^/LH^ transfer
interfaces to preclude cross coupling oi the propellant
tanks.

6.2 RECOMMENDATIONS

1, Studies of flame propagation and explosive phenomena in
space would be valuable in the event that the results of
this study are to be expanded.

2. The explosive studies should address the problem of
possible failure because of debris following an explosion.

15

DISTRIBUTION

Internal

Bello, M.
Donabedian, M.
0*Brien, N. R.
Sitney, L. T.
Steinman, J .
Toutant, R. P.
Willens, D.

Wolfe, R. R.
Yoshikawa, H. H.

External

NASA Scientific and Technical (3)

Information Facility
P.O. Box 33

College Park, Maryland 20740

NASA Headquarters

Washington, D.C. 20546

Attn: New Technology Representative

Code: UT

NASA Headquarters
Washington D.C. 20546

Attn: Code: MTE (50)

SAMSO(XRZT)

Air Force Unit Post Office
Los Angeles, Calif. 90045
Attn: Lt Col R. S. Bearman

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