Simple, reliable ground-hold refrigeration system for common-bulkhead tank meets design criteria and objectives for ground-hold of oxygen difluoride and diborane. System is failsafe and malfunctions can be rectified without interruption of basic system functions

Stone, G. R.

English

NASA Technical Reports Server

September 1972	 B72-10276 
NASA TECH BRIEF 
Ames Research Center
	 -4r 
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.C. 20546. 
Thermal Control for Storage of Cryogenic Propellants

in a Common-Bulkhead Tank - A Concept 
The storage of toxic, cryogenic propellants in 
spacecraft propulsion modules presents a problem in 
ground equipment design for spacecraft support dur-
ing the prelaunch period, especially if the spacecraft 
must remain in a loaded ready-for-launch condition 
for periods up to 30 days. Design criteria for ground-
hold refrigeration systems usually require that haz-
ardous propellants be held within a given low tem-
perature range corresponding to reasonably low 
vapor pressures, and that there be no venting of 
vapor. Design objectives also include the use of non-
toxic refrigerants, readily available consumables, no 
electromechanical refrigeration, no dependence on 
elctric power except for sensing, and no dependence 
on pneumatic power (unless power valves are in-
stalled in a power-failure—system-safe mode). 
During a study of the problem, consideration was 
given to a thermal control system which would meet 
design criteria and objectives for groundhold of oxy-
gen difluoride (OF2) and diborane (B2H6) stored in a 
common-bulkhead tank. 
A simple, reliable ground-hold refrigeration system 
for the common-bulkhead tank is shown in the dia-
gram. The elevated liquid-nitrogen storage tank pro-
vides a positive head of liquid nitrogen (LN2) to the 
spacecraft and to the heat exchanger coils of the OF2 
tank. The LN2 storage tank is vented to atmosphere, 
and there is no dependence on a pressurization sys-
tem for the liquid nitrogen supply. The supply valve 
to the spacecraft fails open (safe) on loss of pneumatic 
power or loss of electrical power to the pneumatic 
system. An emergency bypass valve is provided in the 
event the remote controlled valve should for some
reason stick or freeze in the closed position. 
The vent side of the refrigeration line is controlled 
by a vent valve and pressure controller which is acti-
vated by signals from an ullage pressure transducer 
From OF2 Tank 
Ullage Transducer 
Relief
GN2 Vent Valve, 
Normally Closed 
LN 2 Supply Valve, 
Normally Open, and 
Manual Bypass 
To Rocket 
Propellant 
System 
in the OF2 tank as the liquid temperature and vapor 
pressure of the OF2 rises or falls. The vent valve 
cycles slowly between an open and closed position 
to maintain OF2 temperature somewhat above or 
below the setpoint. 
Once loaded, the propellant tanks can be discon-
nected from ground loading systems and locked to 
(continued overleaf) 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States	 information contained in this document, or warrants that such use 
Government .nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19720000275 2020-03-17T03:28:55+00:00Z
assure a 100-percent propellant load and a leak-free 
operation during space residency. Also, there is no 
propellant flow between spacecraft and ground sys-
tems; only LN2 is vented. For any component failure 
short of rupture of the LN2 line, the system is fail-
safe, and malfunctions can be rectified without inter-
ruption of basic system functions. 
The common-bulkhead tank arrangement has also 
been considered for fluorine-oxygen/methane designs, 
where details would be different, but the thermal 
control concept is applicable to achieve a common 
propellant temperature of 100'K. 
Notes: 
1. The following documentation may be obtained 
from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95)
Reference: 
NASA CR-109833 (N70-27095), Prelaunch 
Operations for A Space Storable Propellant 
Module. 
2. See also Tech Briefs B72-10277 and B72-10278. 
3. No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B72-10276 
Patent status: 
No patent action is contemplated by NASA. 
Source: Gordon R. Stone of 
General Dynamics/Convair Division 
under contract to 
Ames Research Center 
(ARC-10558) 
B72-10276	 Category 03


Thermal control for storage of cryogenic propellants in a common-bulkhead tank: A concept

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