Lunar dust poses a technical challenge for sealing applications on the moon. A survey of seals used in Apollo lunar missions is presented as well as lunar soil characteristics and a description of the lunar environment. Seal requirements and technical challenges for the volatiles characterization oven and hydrogen reduction reaction chamber of the RESOLVE project are discussed. The purpose of the RESOLVE project is to find water or ice in lunar soil and demonstrate the ability to produce water, and hence oxygen and hydrogen, from lunar regolith for life support and propellants

Dempsey, Paula

Proctor, Margaret P.

NASA Technical Reports Server

“Survey of Dust Issues for Lunar Seals and the RESOLVE Project” 
By  Margaret P. Proctor and Paula Dempsey 
 
Abstract 
Lunar dust poses a technical challenge for sealing applications on the moon.  A survey of 
seals used in Apollo lunar missions is presented as well as lunar soil characteristics and a 
description of the lunar environment.  Seal requirements and technical challenges for the 
volatiles characterization oven and hydrogen reduction reaction chamber of the 
RESOLVE project are discussed.  The purpose of the RESOLVE project is to find water 
or ice in lunar soil and demonstrate the ability to produce water, and hence oxygen and 
hydrogen, from lunar regolith for life support and propellants. 
 
https://ntrs.nasa.gov/search.jsp?R=20070010457 2019-08-30T00:36:23+00:00Z
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 (2
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 N
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ax
 1
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rth
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 1
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12
N
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io
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er
on
au
tic
s 
an
d 
Sp
ac
e 
Ad
m
in
is
tra
tio
n
w
w
w
.n
as
a.
go
v
Th
e 
R
ES
O
LV
E 
pr
oj
ec
t
•
Pu
rp
os
e:
–
fin
d 
w
at
er
 o
r i
ce
 in
 lu
na
r s
oi
l
–
de
m
on
st
ra
te
 th
e 
ab
ilit
y 
to
 p
ro
du
ce
 w
at
er
 a
nd
 h
en
ce
 o
xy
ge
n 
an
d 
hy
dr
og
en
 fo
r l
ife
 s
up
po
rt 
an
d 
pr
op
el
la
nt
s 
fro
m
 lu
na
r 
re
go
lit
h.
•
H
ow
 w
ill
 th
is
 b
e 
do
ne
?
–
C
or
e 
sa
m
pl
es
 o
f l
un
ar
 re
go
lit
h 
he
at
ed
 in
 a
 V
ol
at
ile
s 
C
ha
ra
ct
er
iz
at
io
n 
O
ve
n 
to
 1
50
 ºC
 to
 lo
ok
 fo
r w
at
er
 v
ap
or
 o
r 
ot
he
r v
ol
at
ile
s.
–
H
yd
ro
ge
n 
re
du
ct
io
n 
pr
oc
es
s 
re
ac
ts
 h
yd
ro
ge
n 
to
 th
e 
ox
id
es
 in
 
th
e 
lu
na
r r
eg
ol
ith
 to
 fo
rm
 w
at
er
, w
hi
ch
 c
an
 th
en
 b
e 
sp
lit
 in
to
 
H
2
&
 O
2
us
in
g 
el
ec
tro
ly
si
s.
  P
ro
ce
ss
 re
qu
ire
s 
he
at
in
g 
to
  
~9
00
 ºC
.
13
N
at
io
na
l A
er
on
au
tic
s 
an
d 
Sp
ac
e 
Ad
m
in
is
tra
tio
n
w
w
w
.n
as
a.
go
v
C
on
ce
pt
ua
l I
nt
eg
ra
te
d 
R
ES
O
LV
E 
U
ni
t1
H
2
N
e
G
C
A
nh
yd
ro
us
 S
al
t 
B
ed
 W
at
er
 
C
ap
tu
re
Th
er
m
al
 E
nv
el
op
e
Fi
ll 
V
al
ve
M
et
al
 H
yd
rid
e 
H
2 
C
ap
tu
re
Fi
ll 
V
al
ve
S
V
1
S
V
2
C
ru
sh
er
R
2
R
1
S
ig
ht
 
G
la
ss
C
om
bi
ne
d 
R
V
C
 a
nd
 
H
yd
ro
ge
n 
R
ed
uc
tio
n 
R
O
E
 H
ea
tin
g 
C
ha
m
be
r
M
FC
1
C
V
1 C
V
2
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ot
ar
y
S
el
ec
to
r
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al
ve
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28
V
28
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DD
PP TT
28
V
28
V
PP TT
28
V
28
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er
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am
an
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D
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er
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D
C
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er
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ly
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2
28
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P
T
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ct
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ly
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2
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2
28
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28
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PP
TT
28
V
28
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PP
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28
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28
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PP
TT
28
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28
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28
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V
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S
V
5
Ta
nk
To
 L
un
ar
V
ac
cu
m
1  
Sa
nd
ers
, G
era
ld B
., e
t. a
l., “
Re
go
lith
 & 
En
viro
nm
en
t S
cie
nce
, a
nd
 Ox
yge
n &
 Lu
na
r V
ola
tile
 Ex
tra
ctio
n 
(RE
SO
LV
E) 
 fo
r R
ob
otic
 Lu
na
r P
ola
r L
an
de
r M
iss
ion
,”L
un
ar 
Int
ern
atio
na
l C
on
fer
en
ce 
20
05
.
Cru
she
r
Dri
ll
Ov
en
 & 
Re
act
ion
Ch
am
be
r
An
hyd
rou
s s
alt 
be
d
Wa
ter
 ca
ptu
re
Me
tal 
hyd
rid
e
H2
 ca
ptu
re
Ele
ctr
oly
sis
14
N
at
io
na
l A
er
on
au
tic
s 
an
d 
Sp
ac
e 
Ad
m
in
is
tra
tio
n
w
w
w
.n
as
a.
go
v
Se
al
 R
eq
ui
re
m
en
ts
 fo
r V
ol
at
ile
s 
C
ha
ra
ct
er
iz
at
io
n 
O
ve
n 
(V
C
O
)
•
C
ap
ab
le
 o
f -
23
3 
to
 1
50
 ºC
•
E
ffe
ct
iv
e 
fo
r 0
-7
5 
ps
id
iff
er
en
tia
ls
 (m
ay
 b
e 
re
vi
se
d 
to
 1
50
 p
si
d)
•
Lo
w
 o
r n
o 
ou
t-g
as
si
ng
 in
 a
 v
ac
uu
m
 (l
un
ar
 1
0-
14
at
m
or
 7
.6
 x
 1
0-
12
to
rr
)
•
Le
ak
ag
e 
ra
te
 le
ss
 th
an
 0
.5
 c
m
3 /m
in
 d
ur
in
g 
20
 m
in
ut
es
 p
ro
ce
ss
in
g 
tim
e 
at
 5
 a
tm
di
ffe
re
nt
ia
l a
ss
um
in
g 
H
2
•
C
om
pa
tib
le
 w
ith
 h
yd
ro
ge
n,
 o
xy
ge
n,
 w
at
er
, w
at
er
 v
ap
or
, o
th
er
 v
ol
at
ile
s
•
To
le
ra
nt
 o
f v
ib
ra
tio
ns
 u
p 
to
 1
0g
 a
t 8
0-
10
0 
H
z
•
R
eu
sa
bl
e 
up
 to
 4
0 
op
en
/c
lo
se
 c
yc
le
s
–
R
es
is
ta
nt
 to
 lu
na
r r
ad
ia
tio
n 
en
vi
ro
nm
en
t
–
R
es
is
ta
nt
 to
 d
am
ag
e 
fro
m
 lu
na
r d
us
t
–
M
at
er
ia
l r
ep
el
s 
lu
na
r d
us
t o
r h
as
 m
ea
ns
 to
 re
m
ov
e 
du
st
 fr
om
 s
ea
l*
–
M
at
er
ia
l f
lo
w
s 
ar
ou
nd
 lu
na
r d
us
t t
ra
pp
ed
 a
t s
ea
l i
nt
er
fa
ce
*
•
Li
gh
t w
ei
gh
t  
Æ
S
m
al
l l
oa
d 
to
 a
ch
ie
ve
 a
 s
ea
l
•
In
ex
pe
ns
iv
e
•
H
ig
h 
re
lia
bi
lit
y 
 Æ
Lo
w
 n
um
be
r o
f c
om
po
ne
nt
s
•
G
eo
m
et
ric
al
ly
 c
om
pa
tib
le
 w
ith
 in
te
rfa
ce
 re
qu
ire
m
en
ts
15
N
at
io
na
l A
er
on
au
tic
s 
an
d 
Sp
ac
e 
Ad
m
in
is
tra
tio
n
w
w
w
.n
as
a.
go
v
C
ha
lle
ng
es
 o
f S
ea
lin
g 
H
yd
ro
ge
n 
R
ed
uc
tio
n 
R
ea
ct
io
n 
C
ha
m
be
r
•
S
am
e 
re
qu
ire
m
en
ts
 a
s 
th
e 
vo
la
til
es
 c
ha
ra
ct
er
iz
at
io
n 
ov
en
 e
xc
ep
t:
–
90
0 
ºC
–
3 
ba
tc
he
s 
pr
oc
es
se
d 
at
 9
00
 ºC
•
In
iti
al
 b
en
ch
 te
st
in
g 
al
lo
w
s 
th
e 
vo
la
til
es
 
ch
ar
ac
te
riz
at
io
n 
ov
en
 to
 b
e 
se
pa
ra
te
 fr
om
 th
e 
hy
dr
og
en
 re
du
ct
io
n 
ch
am
be
r.
•
W
an
t t
he
 s
am
e 
ch
am
be
r f
or
 b
ot
h 
pr
oc
es
se
s 
to
 
re
du
ce
 w
ei
gh
t .
16
N
at
io
na
l A
er
on
au
tic
s 
an
d 
Sp
ac
e 
Ad
m
in
is
tra
tio
n
w
w
w
.n
as
a.
go
v
S
om
e 
O
pt
io
ns
 fo
r S
ea
lin
g 
V
C
O
•
O
-R
in
gs
–
M
et
al
–
V
ito
n
A
 -
–
Te
flo
n 
–
co
ld
 fl
ow
s 
ar
ou
nd
 s
in
gl
e 
la
ye
r o
f d
us
t p
ar
tic
le
•
Tu
ng
st
en
 C
ar
bi
de
 K
ni
fe
 e
dg
e 
on
 T
un
gs
te
n 
C
ar
bi
de
–
K
ni
fe
 is
 v
er
y 
ha
rd
 a
nd
 v
er
y 
sh
ar
p 
fo
r c
ut
tin
g 
an
y 
pa
rti
cl
es
 
be
tw
ee
n 
it 
an
d 
th
e 
ha
rd
 fl
at
 s
ea
lin
g 
su
rfa
ce
•
K
ni
fe
 e
dg
e 
in
to
 In
di
um
 o
r o
th
er
 s
of
t m
et
al
 th
at
 c
ou
ld
 
be
 re
-m
el
te
d 
af
te
r e
ac
h 
us
e 
to
 re
st
or
e 
th
e 
“g
as
ke
t”
m
at
er
ia
l.
Ke
y:  
Pro
tec
t se
alin
g s
urf
ace
 fro
m 
du
st !
17
N
at
io
na
l A
er
on
au
tic
s 
an
d 
Sp
ac
e 
Ad
m
in
is
tra
tio
n
w
w
w
.n
as
a.
go
v
A
 V
ol
at
ile
s 
C
ha
ra
ct
er
iz
at
io
n 
O
ve
n 
C
on
ce
pt
Ov
en
He
ate
r
Se
al g
roo
ve
Fill
 op
en
ing
18
N
at
io
na
l A
er
on
au
tic
s 
an
d 
Sp
ac
e 
Ad
m
in
is
tra
tio
n
w
w
w
.n
as
a.
go
v
S
um
m
ar
y
•
Lu
na
r d
us
t p
os
es
 a
 c
ha
lle
ng
e 
to
 lo
ng
 te
rm
 m
is
si
on
s 
on
 th
e 
m
oo
n.
•
A
ss
es
sm
en
t o
f m
at
er
ia
l c
ap
ab
ili
tie
s 
in
 th
e 
lu
na
r 
en
vi
ro
nm
en
t i
s 
ne
ed
ed
.
•
P
ro
te
ct
in
g 
an
d/
or
 c
le
an
in
g 
se
al
in
g 
su
rfa
ce
s 
of
 lu
na
r 
du
st
 m
us
t b
e 
ad
dr
es
se
d 
fo
r r
e-
us
ab
le
 s
ea
ls
.
•
Th
e 
R
E
S
O
LV
E
 p
ro
je
ct
 p
os
es
 a
 c
ha
lle
ng
in
g 
se
al
 
pr
ob
le
m
.


Survey of Dust Issues for Lunar Seals and the RESOLVE Project

Lunar dust poses a challenge to long term missions on the moon. Assessment of material capabilities in the lunar environment is needed. Protecting and/or cleaning sealing surfaces of lunar dust must be addressed for re-usable seals. The RESOLVE project poses a challenging seal problem

Dempsey, Paula J.

SURVEY OF DUST ISSUES FOR LUNAR SEALS AND THE RESOLVE PROJECT 
 
Margaret P. Proctor and Paula J. Dempsey 
National Aeronautics and Space Administration 
Glenn Research Center 
Cleveland, Ohio  
National Aeronautics and Space Administration
www.nasa.gov
Survey of Dust Issues for Lunar Seals
and the RESOLVE Project
By
Margaret P. Proctor and Paula J. Dempsey
Seals Team of the Mechanical Components Branch
Structures and Materials Division
NASA Glenn Research Center
Cleveland, OH
Presented at the 
2006 NASA Seal/Secondary Air System Workshop
November 14-15, 2006
NASA/CP—2007-214995/VOL1 477
https://ntrs.nasa.gov/search.jsp?R=20080003835 2019-08-29T19:10:10+00:00Z
National Aeronautics and Space Administration
www.nasa.gov
Challenges of Future Lunar Exploration
“Dust represents the single largest technical challenge to prolonged 
human presence on the Moon.”
Harrison Schmidtt, Apollo 17 Astronaut March 2005
• The extent and duration of planned lunar surface activities is much 
higher than prior Apollo experiences.  
• Systems and components will be exposed to environmental factors 
for periods of time orders of magnitude longer than those 
previously addressed.  
Dust mitigation strategies:
1. Design systems tolerant of dust properties
2. Develop techniques to clean or remove dust from surfaces
3. Active abatement methods to minimize or eliminate deposition 
and/or adhesion of dust
Self-explanatory
NASA/CP—2007-214995/VOL1 478
National Aeronautics and Space Administration
www.nasa.gov
Apollo Lunar Sample Return Containers 
a.k.a. “Rock Boxes”
• Used to return lunar 
regolith samples to earth 
• Triple seals designed to 
provide a vacuum seal of 
10-6 torr 
• Aluminum box (7075 AA) 
with Knife edge seal in soft 
indium alloy (90% indium, 
10% silver), 150 cm long
Of the 12 Rock Boxes, 4 had substantial leaks due to bag material or dust on sealing surface1
•Teflon spacer prevents contact prior to use.
•Single use and pressure required to maintain sealing.
•Double O-rings (L608-6 fluorosilicone) for add’l sealing.
The Apollo Lunar Sample Return Container (ALSRC) maintained a  lunar-
like vacuum around the samples until they were opened in the Lunar 
Receiving Laboratory. In practice, substantial leakage was detected in 4 of 
the 12 ALSRC's returned from the moon due to pieces of equipment or dust 
interfering with the seals.
1 Stansbery, E.K., Kaplan, D.I., Allton, J.H. and Allen, C.C.(1997) Planetary 
Protection Issues for a Mars Sample Return Mission.  Report to the NASA 
Planetary Protection Officer.  October 1997
NASA/CP—2007-214995/VOL1 479
National Aeronautics and Space Administration
www.nasa.gov
Apollo 
Special Environmental Sample Containers
• 340L S.S. with knife edge seal into indium alloy
• 18 cm long
• At end of Apollo missions, no reports of leakage
NASA/CP—2007-214995/VOL1 480
National Aeronautics and Space Administration
www.nasa.gov
Apollo Space Suits
Space Suits
• Designed to operating pressure: 3.75psig (25.8 KPa), 
temperature: + 250 oF (+ 394 oK),
maximum leak rate: 0.0315 lb/hr (180 scc/min)
• Leakage increased with use.
Apollo Helmet Attaching Neck Ring
• Manufactured by Air-lock Inc. 
• Aluminum alloy 7070-T6 treated with an anodized coating. 
• Helmet  disconnects  have interior stainless steel bearings
• Seals in the Extravehicular Mobility Suits (EMS) were used to 
attach the space helmets to the spacesuit by a pressure-sealing 
neck ring.
• Between Extra-Vehicular Activities (EVAs) the  helmet 
disconnect seals were cleaned and re-lubricated with Krytox oil 
and grease to reduce leakage.
1. Carson, M.A., Rouen, M.N., Lutz, C.C. and McBarron, J.W.(1975) Biomedical 
Results of Apollo.  Chapter 6 Extravehicular Mobility Unit. NASA SP-368
2. Young, L.A. and Young, A.J. The Preservation, Storage, and Display of 
Spacesuits.  Smithsonian National Air and Space Museum Collection Care, 
Reprot Number 5, December 2001.
3. Apollo Operations Handbook (1971) Extravehicular Mobility Unit. Volume I. 
System Description.  CSD-A-789-(1). Revision V, March 1971.
4. Gaier, J.R. (2005) The Effects Of Lunar Dust On Eva Systems During The 
Apollo Missions.  NASA TM 2005-213610, March 2005.
NASA/CP—2007-214995/VOL1 481
National Aeronautics and Space Administration
www.nasa.gov
Apollo Helmet Attaching Neck Ring
• Attached to suit by a self-latching self-sealing quick 
disconnect coupling 
It has….
•Neck ring housing
•8 latch 
assemblies
•A rotating lock 
ring
•Push button lock 
assembly on the 
locking ring.
Latch
Command Module Pilot (CMP) Helmet
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Apollo Space Suits
Glove Disconnect Assembly
• Manufactured by Air-lock Inc. 
• Aluminum alloy 2024-T4. 
• Have interior stainless steel bearings.
• Pressure-sealing disconnects attached gloves to spacesuit
• arms 
• Wrist bearings and rotational hardware connectors had fabric 
coverings to keep out the dust.
• Between EVAs glove disconnect seals were cleaned and re-
lubricated with Krytox oil and grease to reduce leakage.
• Air-lock has a patent (4596054) on the synthetic resin lip seal 
used in the bearing assembly of the space suit at the rotary 
motion locations, such as at the glove connection. 
• The suit side has a manually actuated lock/unlock mechanism.
• The glove has a sealed bearing that permits 360o glove rotation.
1. Young, L.A. and Young, A.J. The Preservation, Storage, and Display of 
Spacesuits.  Smithsonian National Air and Space Museum Collection Care, 
Reprot Number 5, December 2001.
2. Apollo Operations Handbook (1971) Extravehicular Mobility Unit. Volume I. 
System Description.  CSD-A-789-(1). Revision V, March 1971.
3. Gaier, J.R. (2005) The Effects Of Lunar Dust On Eva Systems During The 
Apollo Missions.  NASA TM 2005-213610, March 2005.
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Apollo Space Suits-Glove Disconnect Assembly
Reference: Apollo Operations Handbook (1971) Extravehicular Mobility Unit.  Volume I. CSD-A-789-(1)
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Lunar Soil Characteristics
0.3 (compression index)Compressibility (loose)
1.72-2.95 x 10-4 W/cm oK (Apollo 17)Thermal Conductivity
<20 μm high ferromagnetic susceptibilityMagnetic
Highly chargedElectrostatic
Not active in vacuumCorrosiveness
Primarily non-toxicToxicity
0.52 KPa (.0053 kg/cm2; .0754 psi)Cohesion (0-15 cm)
52% + 2%Porosity  (0-15 cm)
5-7  ( Mohs scale)Hardness
1.58 + g/cm3Bulk Density  (0-30 cm)
Angular/subangular sharpShape
90% < 1000 μm, 70% < 100 μmSize
DescriptionCharacteristic
Reference: Fuhs, S., Harris, J.(1992) Dust Protection for Environmental Control and Life  Support Systems in 
the Lunar Environment. Proceedings of the Lunar Materials Technology Symposium.  
Size  1000 μm=1 mm=.04”
Bulk density - property of particulate materials. mass particles divided by the volume they occupy. 
The volume includes the space between particles as well as the space inside the pores of individual 
particles. 
Hardness - resistance to permanent deformation (Diamond=10, Quartz=7, Gypsum=2)
Porosity of a porous medium (such as rock or sediment) describes how densely the material is 
packed. It is the proportion of the non-solid volume to the total volume of material.  15 cm depth 
measurement?
Cohesion-particles stick together 
Electrostatic- forces exerted by a static (i.e. unchanging) electric field upon charged objects
Magnetic- Susceptibility of Soil Particles Increases as Grain Size Decreases;  Effects of Vapor-
Deposited Nanophase Feo  are a Direct Function of Surface Area and Most  Pronounced in the 
Finest Grain Sizes; Virtually All <10 μm Particles are Easily Attracted by a Simple Hand-held 
Magnet
Thermal Conductivity- ability to conduct heat. Apollo 17 heat flow probes 2.36 m
Copper is 385 W/m-K, 3.85 W/cm-K
Compressibility is a geological term used to quantify the ability of a soil to reduce in volume with 
applied pressure 
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Lunar Soil Composition 
Oxygen
Magnesium
Calcium
Aluminum
Iron
Silicon
Titanium
Other
Sodium          0.2 %
Manganese   0.2 %
Potassium     0.1 %
Chromium     0.1 %
Nickel         300 ppm
Hydrogen   100 ppm
Carbon       100 ppm
Nitrogen       80 ppm
Copper            5 ppm
Thorium          1 ppm
Reference: McKay, D.S. and Taylor, L. (2005) Nature and Evolution Of Lunar Soil. 
42%
21%
13%
7%
8%
6%
2% + Other
Composition from Apollo mission samples at specific sites
Other
Titanium 2%????
Sodium          0.2 %
Manganese   0.2 %
Potassium     0.1 %
Chromium     0.1 %
Nickel         300 ppm
Hydrogen   100 ppm
Carbon       100 ppm
Nitrogen       80 ppm
Copper            5 ppm
Thorium          1 ppm
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Lunar Environment
Helium  (25);Neon (25);Hydrogen(23);Argon(20); 
Trace: Methane; Ammonia; Carbon Dioxide Atmosphere (%)
Galactic cosmic rays (GCR)
Solar particle events (SPE)  wind, cosmic rays 
Lunar Radiation Sources
Min -181 C (92 K) Max 111 C (384 K)Measured Surface Temps. (Apollo) 
3 x 10-13 KPa (2 x 10-12 torr) Atmospheric Pressure
27.32 Earth daysOrbital Period around earth
1.63 m/sec2Surface gravity
3.34 g/cm3Density
7.35 x 10E22 kgMass
37.8 x 106 km2Surface area
1738.1 kmEquatorial radius
Summary of radiation found on page 48 of:
Heiken, G.H., Vaniman, D.T. And French, B.M., “LUNAR SOURCEBOOK, A 
User’s Guide to the Moon,” Cambridge University Press 1991.
Estimated lunar surface temperature of 40K from Lunar Study Group in 1972 based 
on Earth-based observations and need to be updated with actual measurements on 
the Lunar surface. 
Dalton, C. and Hoffman, E. (1972) "Conceptual Design of a Lunar Colony" NASA 
Grant Rpt. NGT 44-005-114, NASA, Washington, D.C.
Shakleton Crater
Due to this almost constant illumination, the crater rim is considered a preferable 
location for a future lunar outpost.[9] The light could be converted into electricity
using solar panels. The temperature at the location is also more favorable than on
most of the surface, and does not experience the extremes along the lunar equator 
where it rises to 100 °C when the Sun is overhead, to as low as −150 °C during the 
lunar night. The continuous shadows in the south polar craters cause the floors of 
these formations to maintain a temperature that never exceeds about −173 °C, or 
100 K.
http://www.answers.com/topic/shackleton
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The RESOLVE project
• Purpose:
– find water or ice in lunar soil
– demonstrate the ability to produce water and hence oxygen 
and hydrogen for life support and propellants from lunar 
regolith.
• How will this be done?
– Core samples of lunar regolith heated in a Volatiles 
Characterization Oven to 150 ºC to look for water vapor or 
other volatiles.
– Hydrogen reduction process reacts hydrogen to the oxides in 
the lunar regolith to form water, which can then be split into 
H2 & O2 using electrolysis.  Process requires heating to  
~900 ºC.
Self-explanatory
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Conceptual Integrated RESOLVE Unit1
H2
Ne
GC
Anhydrous Salt 
Bed Water 
Capture
Thermal Envelope
Fill 
Valve
Metal Hydride 
H2 Capture
Fill 
ValveSV1
SV2
Crusher
R2
R1
Sight 
Glass
Combined RVC and 
Hydrogen Reduction 
ROE Heating Chamber
MFC1CV1
CV2
Rotary
Selector
Valve
28
V
28V D
P
T
28V
P
T
28V
P
T
Camera
Raman
28
V D
28
V
28
V DD
Camera
Raman
28
V
D2
8V28
V
DD
Electrolysis
O2
H2
28V P T
28V P T 28V P T
28V
28V
SV4
Drill
Orifice
SV3
28V
28V
28V
CV3
P
T
28V
SV5RV1
28V
SV5
Tank
To Lunar
Vaccum
1  Sanders, Gerald B., et. al., “Regolith & Environment Science, and Oxygen & Lunar Volatile Extraction 
(RESOLVE)  for Robotic Lunar Polar Lander Mission,” Lunar International Conference 2005.
Crusher
Drill
Oven & 
Reaction
Chamber
Anhydrous salt bed
Water capture
Metal hydride
H2 capture
Electrolysis
1 Sanders, Gerald B., et. al., “Regolith & Environment Science, and Oxygen & 
Lunar Volatile Extraction (RESOLVE)  for Robotic Lunar Polar Lander Mission,”
Lunar Interanational Conference 2005.
Lunar regolith is loaded into the crusher, goes to heating chamber for volatiles 
characterization, and hydrogen reduction process.  Off-gases from the oven pass 
through anhydrous salt bed for water capture.  Water then goes through electrolysis 
to produce oxygen and hydrogen.  For hydrogen reduction  process, hydrogen is 
supplied to the reaction chamber (oven).  Again the off-gases pass through the 
anhydrous salt bed for water capture.  Remaining gases pass through a metal 
hydride bed for hydrogen capture.  
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Seal Requirements for Volatiles Characterization 
Oven (VCO)
• Capable of -233 to 150 ºC
• Effective for 0-75 psi differentials (may be revised to 150 psid)
• Low or no out-gassing in a vacuum (lunar 10-14 atm or 7.6 x 10-12 torr)
• Leakage rate less than 0.5 cm3/min during 20 minutes processing time 
at 5 atm differential assuming H2
• Compatible with hydrogen, oxygen, water, water vapor, other volatiles
• Tolerant of vibrations up to 10g at 80-100 Hz
• Reusable up to 40 open/close cycles
– Resistant to lunar radiation environment
– Resistant to damage from lunar dust
– Material repels lunar dust or has means to remove dust from seal*
– Material flows around lunar dust trapped at seal interface*
• Light weight  Æ Small load to achieve a seal
• Inexpensive
• High reliability  Æ Low number of components
• Geometrically compatible with interface requirements
Self-explanatory
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Challenges of Sealing Hydrogen Reduction 
Reaction Chamber
• Same requirements as the volatiles characterization 
oven except:
– 900 ºC
– 3 batches processed at 900 ºC
• Initial bench testing allows the volatiles 
characterization oven to be separate from the 
hydrogen reduction chamber.
• Want the same chamber for both processes to 
reduce weight .
Self-explanatory
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Some Options for Sealing VCO
• O-Rings
– Metal
– Viton A -
– Teflon – cold flows around single layer of dust particle
• Tungsten Carbide Knife edge on Tungsten Carbide
– Knife is very hard and very sharp for cutting any particles 
between it and the hard flat sealing surface
• Knife edge into Indium or other soft metal that could 
be re-melted after each use to restore the “gasket”
material.
Key:  Protect sealing surface from dust !
Self-explanatory
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A Volatiles Characterization Oven Concept
Oven
Heater
Seal groove
Fill opening
This is a cross sectioned view of a concept design being considered for the Volatiles 
Characterization Oven. The yellow oven rotates relative to the brown lid to the fill 
opening for loading regolith into the oven.  Heating of the regolith occurs in the 
position shown in this chart.  To dump the regolith the yellow oven and brown lid 
rotate ~180 degrees to the right and the yellow container rotates to align with the fill 
opening.  Some type of o-ring would ride in the seal groove.  The o-ring would be 
subject to sliding motion. The lid would shield the o-ring during the fill operation.  
However, it may still  be necessary to provide a means to provide a wiper to clear 
any dust that may fall onto the o-ring as it slides past the fill opening.
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Summary
• Lunar dust poses a challenge to long term missions 
on the moon.
• Assessment of material capabilities in the lunar 
environment is needed.
• Protecting and/or cleaning sealing surfaces of lunar 
dust must be addressed for re-usable seals.
• The RESOLVE project poses a challenging seal 
problem.
Self-explanatory
NASA/CP—2007-214995/VOL1 494


Survey of Dust Issues for Lunar Seals and the RESOLVE Project

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