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Final Results for the GRC Supporting Technology Development Project for the 110-Watt Stirling Radioisotope Generator (SRG110)
Jeffrey G. Schreiber and Lanny G. Thieme
Abstract. From 1999-2006, the NASA Glenn Research Center (GRC) supported the development of a high-efficiency, nominal 110-We Stirling Radioisotope Generator (SRG110) for potential use on NASA missions, including deep space missions, Mars rovers, and lunar applications. Lockheed Martin (LM) was the system integrator for the SRG110, under contract to the Department of Energy (DOE). Infinia Corporation (formerly Stirling Technology Company) developed the Stirling convertor, first as a contractor to DOE and then under subcontract to LM. The SRG110 development has been redirected, and recent program changes have been made to significantly increase the specific power of the generator. System development of an Advanced Stirling Radioisotope Generator (ASRG) has now begun, using a lightweight, advanced convertor from Sunpower, Inc. This paper summarizes the results of the supporting technology effort that GRC completed for the SRG110. GRC tasks included convertor extended-duration testing in air and thermal vacuum environments, heater head life assessment, materials studies, permanent magnet aging characterization, linear alternator evaluations, structural dynamics testing, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) characterization, organic materials evaluations, reliability studies, and development of an end-to-end system dynamic model. Related efforts are now continuing in many of these areas to support ASRG development.
https://ntrs.nasa.gov/search.jsp?R=20070017911 2018-04-19T18:12:17+00:00Z
1
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iona
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e Ad
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Fina
l Res
ults
for t
he G
RC
Sup
porti
ng
Tech
nolo
gy D
evel
opm
ent P
roje
ct fo
r the
110
-W
att S
tirlin
g R
adio
isot
ope
Gen
erat
or (S
RG
110)
pres
ente
d at
the
2007
Spa
ce T
echn
olog
y A
pplic
atio
ns In
tern
atio
nal F
orum
Alb
uque
rque
, NM
Febr
uary
13,
200
7
byJe
ffrey
G. S
chre
iber
and
Lan
ny G
. Thi
eme
NA
SA
Gle
nn R
esea
rch
Cen
ter
Cle
vela
nd, O
H
2
Nat
iona
l Aer
onau
tics
and
Spac
e Ad
min
istra
tion
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Dev
elop
men
t of t
he S
RG
110
•10
0-W
cla
ss, h
igh-
effic
ienc
y po
wer
sou
rce
for
NA
SA
Spa
ce S
cien
ce m
issi
ons
–U
nman
ned
Mar
s ro
vers
for l
ong-
dura
tion
mis
sion
s–
Spa
cecr
aft e
lect
ric p
ower
for d
eep
spac
e m
issi
ons
–P
oten
tial f
or lu
nar d
istri
bute
d po
wer
•In
finia
deve
lope
d th
e Te
chno
logy
Dem
onst
ratio
n C
onve
rtor u
nder
con
tract
to D
OE
sta
rting
in 1
998
•Te
chno
logy
Rea
dine
ss A
sses
smen
t in
1999
•LM
was
sel
ecte
d as
the
Sys
tem
Inte
grat
ion
Con
tract
or fo
r the
SR
G11
0 in
May
200
2•
Flig
ht d
evel
opm
ent c
ontin
ued
at L
M, I
nfin
ia, a
nd
GR
C w
orki
ng in
par
tner
ship
thro
ugh
2005
•N
AS
A G
RC
pro
vide
d:–
Tech
nica
l con
sulti
ng fo
r DO
E/L
M–
In-h
ouse
sup
porti
ng te
chno
logy
dev
elop
men
t pro
ject
Syst
em In
tegr
atio
n C
ontr
acto
r
Mis
sion
sM
issi
ons
Oth
erO
rgan
izat
ions
Tech
nica
l Con
sulta
ntSt
irlin
gEx
perti
se
Stir
ling
Sup
plie
r
Supp
ly P
ower
S
yste
m
Stirl
ing
Rad
iois
otop
e G
ener
ator
(SR
G) T
eam
Syst
em In
tegr
atio
n C
ontr
acto
rSy
stem
Inte
grat
ion
Con
trac
tor
Mis
sion
sM
issi
ons
Mis
sion
s
Oth
erO
rgan
izat
ions
Tech
nica
l Con
sulta
ntSt
irlin
gEx
perti
se
Stir
ling
Sup
plie
rS
tirlin
gS
uppl
ier
Supp
ly P
ower
S
yste
m
Stirl
ing
Rad
iois
otop
e G
ener
ator
(SR
G) T
eam
3
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GR
C S
uppo
rting
Tec
hnol
ogy
for t
he S
RG
110
•C
onve
rtor p
erfo
rman
ce v
erifi
catio
n–
Ext
ende
d op
erat
ion
–C
ontro
ller t
ests
–Th
erm
al v
acuu
m te
st•
Hea
ter h
ead
life
asse
ssm
ent a
nd m
ater
ials
st
udie
s•
Mag
net a
ging
cha
ract
eriz
atio
n an
d lin
ear
alte
rnat
or a
naly
sis
and
test
ing
•C
onve
rtor s
truct
ural
dyn
amic
s•
EM
I/EM
C re
duct
ion
and
char
acte
rizat
ion
•E
valu
atio
n of
con
verto
r org
anic
s•
Rel
iabi
lity
eval
uatio
n•
Ele
ctric
al in
terfa
ce•
Ther
mod
ynam
ic a
nd s
yste
m d
ynam
ic a
naly
ses
4
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iona
l Aer
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e Ad
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Stir
ling
Con
verto
r Tes
ting
at G
RC
•E
xten
ded
Ope
ratio
n of
TD
C’s
#13
and
#14
–B
uilt
unde
r QA
sys
tem
, but
not
her
met
ical
ly s
eale
d–
Look
for i
ndic
atio
ns o
f cha
nge
in o
pera
tion
–Te
st c
apab
ility
was
dev
elop
ed fo
r •
24/7
ope
ratio
n, w
ith c
ontro
l of T
hot,
Tcol
d, a
nd T
pv•
Mea
sure
men
ts o
f tem
pera
ture
s, p
ower
, vib
ratio
n, e
tc•
Ana
lysi
s of
wor
king
flui
d co
mpo
sitio
n–
Firs
t ope
rate
d in
Apr
il 03
–E
xten
ded
oper
atio
n be
gan
in J
une
03 fo
llow
ing
40
hour
s of
che
ck o
ut–
By
Oct
ober
03,
afte
r 2,3
00 h
ours
of o
pera
tion,
pe
rform
ance
was
dec
reas
ing
very
slo
wly
•Lo
ss o
f ~0.
5 W
per
1,0
00 h
ours
•Th
e w
orki
ng fl
uid
had
incr
easi
ng le
vels
of a
rgon
and
ni
troge
n•
Arg
on c
ame
from
an
insu
latio
n lo
ss te
st•
Spe
cula
ted
that
incr
easi
ng le
vel o
f nitr
ogen
and
pe
rform
ance
cha
nge
wer
e lin
ked
Impu
rity
Con
cent
ratio
ns in
TD
C #
13
050100
150
200
250
300
350
400 0.
050
0.0
1000
.015
00.0
2000
.025
00.0
Run
Tim
e, H
ours
Concentration of CO2, H20 and N2, ppm in He
05101520253035404550
Concentration of Ar, ppm in He
N2
Ar
H2O
CO
2
Bla
ckou
t
5
Nat
iona
l Aer
onau
tics
and
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e Ad
min
istra
tion
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Stir
ling
Con
verto
r Tes
ting
at G
RC
•A
rgon
pur
ge ri
ngs
wer
e ad
ded
over
the
bolte
d fla
nges
•N
itrog
en c
once
ntra
tion
and
perfo
rman
ce le
vele
d of
f, ar
gon
rose
mor
e qu
ickl
y•
Pur
ge g
as w
as c
hang
ed to
hel
ium
in a
fter 5
,873
hou
rs•
Ope
ratio
n co
ntin
ued
thou
ght A
ugus
t 04,
at 9
,045
hou
rs m
ove
to n
ew fa
cilit
y
•O
pera
tion
cont
inue
d un
til s
hutd
own
for h
erm
etic
sea
l wel
ding
in J
anua
ry 0
6 af
ter 1
9,10
8 ho
urs
–Fi
ll tu
be w
as n
ot s
eale
d to
allo
w a
naly
sis
of w
orki
ng fl
uid
com
posi
tion
•V
isua
l ins
pect
ion
of in
tern
al c
ompo
nent
s sh
owed
no
sign
s of
wea
ror
degr
adat
ion
TDC
#13
Pow
er O
utpu
t, M
easu
red
and
Empi
rical
Cor
rect
ion
y =
-0.0
005x
+ 6
6.60
5
y =
-0.0
002x
+ 6
5.62
y =
8E-0
5x +
64.
25
63.0
64.0
65.0
66.0
67.0
68.0
69.0
02,
000
4,00
06,
000
8,00
010
,000
Tim
e (h
rs)
Power Output (Wac)
Mea
sure
d
Cor
rect
ed
Impu
rity
Con
cent
ratio
ns in
TD
C #
13
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
0.0
1000
.020
00.0
3000
.040
00.0
5000
.060
00.0
7000
.080
00.0
9000
.0
Run
Tim
e, H
ours
Concentration of CO2, H20, Ar and N2, ppm in He
N2
Ar
H2O
CO
2
6
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iona
l Aer
onau
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and
Spac
e Ad
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istra
tion
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Stir
ling
Con
verto
r Tes
ting
at G
RC
•TD
C’s
#13
and
#14
are
curr
ently
at 2
7,04
4 ho
urs
•A
ppea
rs to
be
no d
egra
datio
n ot
her t
han
due
to in
itial
ope
ratio
nw
ith
oxyg
en p
erm
eatio
n
•V
aria
tions
in p
erfo
rman
ce a
re m
ostly
the
resu
lt of
the
oper
atin
gpo
int
•N
o si
gn o
f wor
king
flui
d ch
angi
ng d
ue to
out
gass
ing
or d
ecom
posi
tion
of
the
orga
nics
01020304050607080
05,
000
10,0
0015
,000
20,0
0025
,000
Tim
e (h
rs)
Power Output (W)
TDC
#13
TDC
#14
0510152025303540
05,
000
10,0
0015
,000
20,0
0025
,000
Tim
e (h
rs)
Efficiency (%)TD
C #
13TD
C #
14
7
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iona
l Aer
onau
tics
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e Ad
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istra
tion
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Stir
ling
Con
verto
r Tes
ting
at G
RC
•TD
C’s
#15
and
#16
star
ted
exte
nded
ope
ratio
n in
Mar
ch 2
005
•O
pera
tion
befo
re h
erm
etic
sea
l wel
ding
was
at r
educ
ed te
mpe
ratu
res
•H
erm
etic
wel
ded
Oct
ober
200
5 at
4,4
13 h
ours
•N
o si
gn o
f wor
king
flui
d ch
angi
ng d
ue to
out
gass
ing
or d
ecom
posi
tion
of
the
orga
nics
•C
urre
ntly
at 1
3,00
9 ho
urs
01020304050607080
02,
000
4,00
06,
000
8,00
010
,000
12,0
00
Tim
e (h
rs)
Power Output (W)
TDC
#15
TDC
#16
1618202224262830
02,
000
4,00
06,
000
8,00
010
,000
12,0
00
Tim
e (h
rs)
Net Efficiency (%TD
C #1
5
TDC
#16
8
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iona
l Aer
onau
tics
and
Spac
e Ad
min
istra
tion
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Stir
ling
Con
verto
r Tes
ting
at G
RC
•TD
C’s
#5 a
nd #
6 w
ere
oper
ated
in fo
cuse
d te
sts
befo
re e
xten
ded
oper
atio
n in
ther
mal
vac
uum
env
ironm
ent
–In
vest
igat
e pe
rform
ance
in th
erm
al v
acuu
m e
nviro
nmen
t–
Mea
sure
ther
mal
pro
files
to v
alid
ate
anal
ytic
al m
odel
s–
Har
dwar
e si
mila
r in
conf
igur
atio
n to
SR
G11
0 bu
t not
low
mas
s–
Nic
kel h
eat c
olle
ctor
, nic
kel/c
oppe
r col
d fla
nges
, alu
min
um ra
diat
or p
anel
s•
Ope
ratio
n in
ther
mal
vac
uum
beg
an in
Nov
embe
r 04,
24/
7 in
Dec
embe
r 04
•S
ome
hard
war
e m
odifi
catio
ns w
ere
requ
ired,
–
Hea
ter e
lect
ric le
ads,
siz
e of
radi
ator
pan
els,
em
issi
vity
of th
e pr
essu
re v
esse
l•
Com
plet
ed a
t 10,
015
hour
s w
ith n
o ch
ange
in S
tirlin
g pe
rform
ance
Ave
rage
Hot
-end
Tem
p
150
200
250
300
350
400
450
500
550
600
650
010
0020
0030
0040
0050
0060
0070
0080
0090
00
Hou
rs o
f Ope
ratio
n
Temperature, °C
TDC
#5
TDC
#6
Pow
er O
ut
010203040506070
010
0020
0030
0040
0050
0060
0070
0080
0090
00
Hour
s of
Ope
ratio
n
Alternator Output Power, watts
TDC
#5
TDC
#6
Ove
r 104
,000
hou
rs o
f ope
ratio
n on
TD
C’s
at G
RC
9
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iona
l Aer
onau
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e Ad
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istra
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Con
trolle
r Dev
elop
men
t
•C
ontro
ller d
evel
opm
ent w
as b
eing
led
by L
ockh
eed
Mar
tin–
Arc
hite
ctur
e w
as b
ased
on
zene
r dio
de c
ircui
t to
clam
p vo
ltage
with
se
ries/
para
llel t
unin
g ca
paci
tors
–Fe
atur
es to
acc
omm
odat
e:•
End
use
r sho
rt ci
rcui
t (ov
er-c
urre
nt, t
oo m
uch
load
on
Stir
ling)
•E
nd u
ser o
pen
circ
uit (
no p
ower
dra
w, p
ower
dis
sipa
ted
by s
hunt
resi
stor
s)
•G
RC
sup
porte
d LM
effo
rt th
roug
h a
serie
s of
test
s an
d an
alys
es–
Sta
rt-up
test
s–
Tran
sien
t res
pons
e te
sts
–Fr
eque
ncy
resp
onse
test
s–
Per
form
ance
map
ping
ove
r ant
icip
ated
ope
ratin
g co
nditi
ons
–Te
stin
g w
ith v
ario
us li
miti
ng s
cena
rios
to in
vest
igat
e sy
stem
sta
bilit
y –
Sys
tem
Dyn
amic
Mod
elin
g of
con
verto
rs w
ith k
ey fe
atur
es o
f the
co
ntro
ller
10
Nat
iona
l Aer
onau
tics
and
Spac
e Ad
min
istra
tion
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w.n
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Met
allic
Mat
eria
ls•
Cha
ract
eriz
ed IN
718
heat
er h
ead
mat
eria
l and
optim
ized
the
proc
essi
ng fo
r lon
g lif
e•
Dev
elop
ed d
ata
to re
pres
ent t
he m
ater
ial o
n a
prob
abili
stic
bas
is, c
ondu
ct li
fe a
naly
sis
in
prob
abili
stic
term
s•
Bas
ed o
n G
RC
thin
-spe
cim
en (0
.5 a
nd 1
.0 m
m)
cree
p te
stin
g an
d ex
tens
ive
OR
NL
data
base
(up
to 8
7,00
0 ho
urs)
–3
sam
ples
stil
l und
er te
st fr
om 1
sthe
at –
long
est t
est t
o da
te is
47,
430
hour
s•
2ndhe
at o
f IN
718
was
pur
chas
ed a
nd s
ampl
es w
ere
test
ed a
t GR
C–
1 sa
mpl
e st
ill un
der t
est f
rom
2nd
heat
–lo
nges
t tes
t at 2
0,20
8 ho
urs
–S
how
pro
perti
es to
be
equi
vale
nt to
the
orig
inal
hea
t•
255,
411
tota
l hou
rs o
f cre
ep te
sts
•R
egen
erat
or s
inte
ring
optim
izat
ion
to e
nhan
ce b
ond
stre
ngth
and
el
imin
ate
shed
ding
•B
raze
pro
cess
ver
ifica
tion
11
Nat
iona
l Aer
onau
tics
and
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e Ad
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istra
tion
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gov
Hea
ter H
ead
Stru
ctur
al B
ench
mar
k Te
stin
g
•1,
3, a
nd 1
2-m
onth
hea
ter h
ead
stru
ctur
al b
ench
mar
k te
sts
wer
e pe
rform
ed to
fact
or in
bia
xial
stre
ss s
tate
and
val
idat
e an
alys
is–
Test
s w
ere
perfo
rmed
at d
esig
n te
mpe
ratu
re w
ith in
crea
sed
pres
sure
–E
xtre
mel
y sm
all c
reep
stra
ins
wer
e m
easu
red
optic
ally
and
with
ext
enso
met
ers
–O
ne te
st in
clud
ed h
eat c
olle
ctor
and
axi
al p
relo
ad
Hea
ter h
ead
stru
ctur
al b
ench
mar
k te
st
Ben
chm
ark
Tes
t Typ
e A
ccel
erat
ed
Non
-Acc
eler
ated
Tes
t Art
icle
B
itec1
B
itec2
B
itec3
ST
C20
9 ST
C20
6 ST
C21
2
cree
p ra
te
high
m
od. h
igh
mod
. hig
h m
oder
ate
very
low
ve
ry lo
w
Pred
icte
d tim
e to
terti
ary
(day
s)
22
67
67
mod
erat
e hi
gh
high
cr
eep
rate
ve
ry h
igh
high
v.
v. h
igh
low
ve
ry lo
w
low
test
dur
atio
n (d
ays)
30
59
25
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12
Nat
iona
l Aer
onau
tics
and
Spac
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min
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tion
ww
w.n
asa.
gov
Org
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•O
rgan
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are
used
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surfa
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nsul
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13
Nat
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Spac
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min
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tion
ww
w.n
asa.
gov
Mag
nets
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hara
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tech
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Alternator Terminal Voltage (Vrms)
14
Nat
iona
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and
Spac
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min
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tion
ww
w.n
asa.
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Stru
ctur
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Nat
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Spac
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min
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gov
EM
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RC
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gene
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16
Nat
iona
l Aer
onau
tics
and
Spac
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min
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tion
ww
w.n
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gov
Rel
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lity
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natu
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s w
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ear-o
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liabi
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vest
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Tech
niqu
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gle
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inhe
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ver
ifyin
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liabi
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vice
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no
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flig
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from
long
life
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ver 1
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17
Nat
iona
l Aer
onau
tics
and
Spac
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min
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tion
ww
w.n
asa.
gov
Sum
mar
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C s
uppo
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tech
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ffort
for t
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RG
110
was
de
sign
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miti
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risk
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uppo
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18
Nat
iona
l Aer
onau
tics
and
Spac
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istra
tion
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w.n
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gov
Ack
now
ledg
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Dis
clai
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desc
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rese
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was
per
form
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r N
AS
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cien
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issi
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find
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clus
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pre
sent
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thor
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d do
no
t nec
essa
rily
refle
ct th
e vi
ews
of th
e P
rom
ethe
us p
roje
ct o
r th
e N
atio
nal A
eron
autic
s an
d S
pace
Adm
inis
tratio
n
