Partial pressure of carbon dioxide within a space suit is maintained at safe levels by regenerating carbon dioxide with potassium hydroxide solution on board spacecraft or by portable units

Copeland, R. J.

Webbon, B. W.

English

NASA Technical Reports Server

1972	 Brief 72-10168 
NASA TECH BRIEF 
Ames Research Center 
NASA Tech Briefs announce now 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. 
Space-Suit Carbon Dioxide Absorption System - A Concept 
The problem: 
To maintain the partial pressure of carbon dioxide 
within a space suit at a level which ensures health 
and safety; ideally, the system must be self-contained, 
lightweight, regenerable, and able to cope with large 
releases of carbon dioxide such as occur during 
periods when the astronaut exercises violently. 
I Regenerating I I	 I	 I I Backpack I System I 
Valve Disconnect Fittings 
Valve 
Electro-
l ysis Cell t Reac- Reactant 
11	
114 tor Storage
Gas
^Seltor	 I	 "Membrane 
I Air Flow 
H2, CO2 
The solution: 
Absorb carbon dioxide with a solution of potassium 
hydroxide in a membrane gas reactor; the spent 
solution is regenerated on board the spacecraft or 
by portable units. 
How it's done: 
The absorption system in the backpack of the 
space suit is depicted schematically in the diagram. 
It consists simply of an absorber in which a strong 
solution of potassium hydroxide is circulated by a 
pump on one side of a gas-permeable membrane 
while air from the space suit is circulated on the
other side. Carbon dioxide reacts with potassium hy-
droxide to form potassium carbonate; the potassium 
hydroxide solution containing dissolved potassium 
carbonate is passed over the membrane at a rate 
which prevents formation of solid potassium carbon-
ate on the membrane surface. 
Regeneration of the backpack is accomplished by 
connecting it to the regenerating system, which may 
be on board the spacecraft or in a portable unit if 
the sphere of operations is at a considerable distance 
away from the spacecraft. As indicated in the dia-
gram, the spent solution in the backpack is pumped 
through an electrolysis cell where the concentration 
of potassium carbonate in the potassium hydroxide 
circulating solution is reduced by release of carbon 
dioxide; the hydrogen and oxygen also formed by 
electrolysis are separated (along with carbon dioxide) 
and vented or delivered to other spacecraft systems 
for use. Water must be supplied to the regenerant 
system to make up losses from electrolysis. 
Other systems of regeneration may be employed; 
for example, the spent solution from the backpack is 
cooled to precipitate potassium carbonate; the potas-
sium carbonate is filtered off and dissolved in hot 
potassium hydroxide solution before electrolysis. 
Preliminary estimates of the size and weight of the 
overall system have indicated that it may be signif-
icantly smaller than other fully regenerable systems. 
Notes: 
1. Conditions for the electrolytic separation of carbon 
dioxide from alkaline solutions have not been 
established. 
2. Solid chemical absorbents, such as lithium hydrox-
ide or potassium superoxide, have been used in 
(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=19720000168 2020-03-17T03:31:32+00:00Z
the past, but they are not easily regenerated; 
consequently, prohibitively large masses of such 
materials are required to support extended extra-
vehicular activities. 
3. 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-114321, Advanced Extra-
vehicular Protective Systems (AEPS) Study. 
3. No additional documentation is available. Specific
questions, however, may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B 72-10168 
Patent status: 
No patent action is contemplated by NASA. 
Source: Robert J
.
 Copeland and
Bruce W. Webbon of

Vought Missiles and Space Company 
under contract to

Ames Research Center 
(ARC-10546) 
Brief 72-10168	 Category 03, 05


Space-suit carbon dioxide absorption system: A concept

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server