Neutral Mass Spectrometry for Venus Atmosphere and Surface · The assignment • to make precise...
28
Neutral Mass Spectrometry for Venus Atmosphere and Surface Paul Mahaffy NASA Goddard Space Flight Center Code 915, Greenbelt, MD 20771 [email protected] https://ntrs.nasa.gov/search.jsp?R=20070014617 2020-01-17T15:41:16+00:00Z
Transcript of Neutral Mass Spectrometry for Venus Atmosphere and Surface · The assignment • to make precise...
Neu
tral M
ass S
pect
rom
etry
for V
enus
A
tmos
pher
e an
d Su
rfac
e
Paul
Mah
affy
NA
SA G
odda
rd S
pace
Flig
ht C
ente
rC
ode
915,
Gre
enbe
lt, M
D 2
0771
Pa
ul.R
.Mah
affy
@N
ASA
.gov
https://ntrs.nasa.gov/search.jsp?R=20070014617 2020-01-17T15:41:16+00:00Z
90 b
ar C
O2
730
KH
2SO
4cl
ouds
100,
000
x dr
ier
than
Ear
thD
/H 1
60 x
Ear
th(V
enus
onc
e w
et?)
Ther
moc
hem
istry
belo
w c
loud
s
1 ba
r N2,
O2
300
K in
San
Fra
ncis
coR
ecei
ves ½
the
sola
r ra
diat
ion
of V
enus
H2O
clo
uds
Oce
ans,
Life
7 m
bar C
O2
~210
K
H2O
and
CO
2ic
e cl
ouds
D/H
5 x
Ear
thPh
otoc
hem
istry
at su
rfac
e
Why
such
div
erge
nt e
volu
tion
in te
rres
tria
l pla
nets
?
How
uni
que
is o
ur so
lar
syst
em?
The
cha
lleng
e fo
r V
enus
pr
obe
mas
s spe
ctro
met
ry•4
ord
ers o
f mag
nitu
de p
ress
ure
diff
eren
tial o
n tra
ck fr
om a
bove
cl
ouds
to su
rfac
e•t
race
spec
ies m
easu
red
to p
arts
pe
r bill
ion
•9 o
rder
s of m
agni
tude
di
ffer
ence
bet
wee
n at
mos
pher
ic
pres
sure
at s
urfa
ce a
nd io
n so
urce
pre
ssur
e in
mas
s sp
ectro
met
er•5
00 d
egre
e te
mpe
ratu
regr
adie
nt fr
om a
tmos
pher
eab
ove
clou
ds to
surf
ace
•clo
ud d
ropl
ets a
nd a
eros
ols t
hat
can
clog
mas
s spe
ctro
met
er in
let
syst
ems a
nd m
ask
real
ver
tical
va
riatio
ns d
ue to
thei
r co
nden
satio
n on
surf
aces
•a fa
st ri
de to
the
surf
ace
with
an e
ntry
pro
be
The
ass
ignm
ent
•to
mak
e pr
ecis
e (b
ette
r tha
n 1
%) m
easu
rem
ents
of i
soto
pe ra
tios a
nd a
ccur
ate
(5-1
0%)
mea
sure
men
ts o
f abu
ndan
ces o
f nob
le g
as•t
o ob
tain
ver
tical
pro
files
of t
race
che
mic
ally
act
ive
gase
s fro
m a
bove
the
clou
ds a
ll th
e w
ay
dow
n to
the
surf
ace
Mot
ivat
ion
for
impr
oved
mas
s spe
ctro
met
er m
easu
rem
ents
at V
enus
•to
addr
ess f
unda
men
tal i
ssue
s of t
erre
stria
l pla
neta
ry fo
rmat
ion
and
evol
utio
n
Topi
cs
Nea
r ter
m V
enus
scie
nce
goal
s for
che
mic
al a
nd is
otop
ic m
easu
rem
ents
Whe
re h
ave
the
Ven
us m
issi
ons,
to d
ate,
left
us w
ith re
spec
t to
thes
e go
als?
•nob
le g
as e
lem
enta
l and
isot
opic
com
posi
tion
•clo
ud c
hem
istry
•sur
face
scie
nce
The
chal
leng
e of
Ven
us m
ass s
pect
rom
etry
and
futu
re d
irect
ions
Spac
e St
udie
s B
oard
SSE
Str
ateg
y –
July
200
2•T
he fi
rst b
illio
n ye
ars
of s
olar
sys
tem
his
tory
1.W
hat p
roce
sses
mar
ked
the
initi
al s
tage
s of
pla
net a
nd s
atel
lite
form
atio
n?
2. H
ow lo
ng d
id it
take
Jup
iter t
o fo
rm a
nd h
ow d
id th
e fo
rmat
ion
of th
e ga
s an
d ic
e gi
ants
diff
er?
3. W
hat w
as th
e ra
te o
f dec
reas
e of
impa
cts
by c
omet
s, a
ster
oids
, and
oth
er o
bjec
ts
and
how
did
it a
ffect
the
emer
genc
e of
life
?
•Vol
atile
s an
d or
gani
cs: t
he s
tuff
of li
fe
1. W
hat i
s th
e hi
stor
y of
vol
atile
mat
eria
l, es
peci
ally
wat
er, i
n ou
r sol
ar s
yste
m?
2. W
hat i
s th
e na
ture
and
his
tory
of o
rgan
ic m
ater
ial i
n ou
r sol
ar s
yste
m?
3. W
hat p
lane
tary
pro
cess
es a
ffect
the
evol
utio
n of
vol
atile
on
plan
ets?
•The
orig
in a
nd e
volu
tion
of h
abita
ble
wor
lds
1. W
here
are
zon
es in
our
sol
ar s
yste
m w
here
like
can
exi
st a
nd w
hat a
re th
e pr
oces
ses
for p
rodu
cing
and
sus
tain
ing
habi
tabl
e pl
anet
s?
2. D
oes
(or d
id) l
ife e
xist
bey
ond
the
Ear
th?
3. W
hy d
id M
ercu
ry, V
enus
, Ear
th, a
nd M
ars
dive
rge
so m
uch
in th
eir e
volu
tion?
4.
Wha
t haz
ards
do
sola
r sys
tem
obj
ects
pre
sent
to E
arth
?
•How
pla
nets
wor
k 1.
How
do
the
proc
esse
s th
at s
hape
pla
nets
toda
y op
erat
e an
d in
tera
ct?
2. W
hat d
oes
our s
olar
sys
tem
tell
us a
bout
oth
er s
olar
sys
tem
s?
Scie
nce
goal
s -at
mos
pher
e &
surf
ace
chem
ical
& is
otop
e m
easu
rem
ents
Dec
adal
Stu
dy R
ecom
men
datio
ns fo
r Ven
us
Dec
adal
Stu
dy T
hem
es a
nd S
cien
ce Q
uest
ions
for
Ter
rest
rial
Pla
nets
Scie
nce
mea
sure
men
t obj
ectiv
es o
f VIS
E a
re a
s fol
low
s:•D
eter
min
e th
e co
mpo
sitio
n of
Ven
us’a
tmos
pher
e, in
clud
ing
trace
gas
sp
ecie
s and
ligh
t sta
ble
isot
opes
•Acc
urat
ely
mea
sure
nob
le-g
as is
otop
ic a
bund
ance
in th
e at
mos
pher
e•P
rovi
de d
esce
nt, s
urfa
ce, a
nd a
scen
t met
eoro
logi
cal d
ata
•Mea
sure
zon
al c
loud
-leve
l win
ds o
ver s
ever
al E
arth
day
s•O
btai
n ne
ar-I
R d
esce
nt im
ages
of t
he su
rfac
e fr
om 1
0-km
alti
tude
to
the
surf
ace
•Acc
urat
ely
mea
sure
ele
men
tal a
bund
ance
s & m
iner
alog
y of
a c
ore
from
the
surf
ace
•Eva
luat
e th
e te
xtur
e of
surf
ace
mat
eria
ls to
con
stra
in w
eath
erin
g en
viro
nmen
t.
Mot
ivat
ion
for
nobl
e ga
s mea
sure
men
ts a
t Ven
us
Nob
le g
as e
lem
enta
l rat
ios a
nd is
otop
ic fr
actio
natio
n co
nstr
ain
mod
els o
f atm
osph
eric
form
atio
n an
d ev
olut
ion
Inne
r pla
net n
oble
gas
ele
men
tal
abun
danc
es d
o no
t mat
ch th
ose
of th
e su
n or
var
ious
type
s of
chon
drite
s.
The
36A
r/84K
r rat
io a
t Ven
us m
ay
be m
uch
mor
e so
lar l
ike
than
Ea
rth o
r Mar
s.
How
ever
-gr
eat u
ncer
tain
ty in
K
r and
Xe
elem
enta
l abu
ndan
ces
From
Ow
en a
nd B
ar-N
um, O
rig.
of L
ife a
nd th
e Ev
olut
ion
of th
e B
iosp
here
, 31,
435
, 200
1.
Nob
le g
as e
lem
enta
l rat
ios
Xen
on Is
otop
ic C
ompo
sitio
n
Mar
s and
Ven
us v
s. th
e Su
n an
d ch
ondr
ites.
The
Mar
tian
valu
es a
re
esta
blis
hed
from
SN
C
met
eorit
e an
alys
is.
The
frac
tiona
tion
in
Ven
us is
unk
now
n.
If fr
actio
natio
n on
Ven
us
was
foun
d to
be
sim
ilar t
o Ea
rth a
nd M
ars,
then
fr
actio
natio
n co
uld
have
oc
curr
ed in
pla
nete
sim
als
prio
r to
thei
r in
corp
orat
ion
in p
lane
ts
from
Ow
en a
nd B
ar-N
um,
Orig
. of L
ife a
nd th
e Ev
olut
ion
of th
e B
iosp
here
, 31,
435
, 200
1.
Cur
rent
stat
us o
f nob
le g
as m
easu
rem
ents
at
Ven
us
Xe
–no
isot
ope
info
rmat
ion,
upp
er li
mit
on a
bund
ance
Kr
–no
isot
ope
info
rmat
ion,
gre
at u
ncer
tain
ty in
abu
ndan
ce
Pres
ent s
tate
of t
he a
rt in
Ven
us n
oble
gas
mea
sure
men
tsN
oble
gas
ab
unda
nce
Prev
ious
m
easu
rem
ents
no
tes
He
12 (+
24,-8
) p
pm
extra
pola
ted
from
mea
s. >
130
km
Ne
7 +
3 pp
m
4 M
S m
easu
rem
ents
A
r 70
+ 2
5 pp
m
3 M
S an
d 2
GC
mea
sure
men
ts
0.4
+ 0.
14
Ven
era
11 a
nd 1
2 re
prod
uced
m
easu
rem
ents
0.
2 PV
Pro
be H
offm
an a
naly
sis
Kr
0.02
5 PV
Pro
be D
onah
ue a
naly
sis
Xe
0.12
upp
er li
mit
PV P
robe
Don
ahue
ana
lysis
N
oble
gas
is
otop
e ra
tio
Prev
ious
m
easu
rem
ent
note
s
3 He/
4 He
---
3 He
pred
icte
d at
low
ppb
leve
l –
met
hane
or H
2 cou
ld g
ive
H3+
inte
rfere
nce
with
HD
20
Ne/
22N
e 11
.8 +
0.7
Po
tent
ial i
nter
fere
nce
from
40
Ar++
at 2
0 D
a an
d C
O2++
at 2
2 D
a 20
Ne/
21N
e --
-
36A
r/38A
r 5.
56 +
0.6
2 PV
Pro
be D
onah
ue a
naly
sis
5.
08 +
0.0
5 V
ener
a 11
/12
MS
1.03
+ 0
.04
PV P
robe
Don
ahue
ana
lysis
40
Ar/36
Ar
1.19
+ 0
.07
Ven
era
11/1
2 M
S K
r iso
tope
s --
-
Xe
isoto
pes
---
Targ
etac
cura
cy<5
-10%
Targ
etpr
ecis
ion
<1-2
%
Key
futu
re
mea
sure
men
ts
Kr
and
Xe
abun
danc
e an
d is
otop
ic
dist
ribu
tion
App
roac
h fo
r fu
ture
nob
le g
as m
easu
rem
ents
at
Ven
us
Wid
e dy
nam
ic r
ange
mas
s spe
ctro
met
erD
edic
ated
nob
le g
as p
roce
ssin
g un
it to
opt
imiz
e al
l nob
le g
as
mea
sure
men
ts in
clud
ing
Xe
and
Kr
dire
ct s
ampl
ing
m/z
(am
u)0
1020
3040
5060
7080
9010
0
counts/second
1e+0
1e+1
1e+2
1e+3
1e+4
1e+5
1e+6
1e+7
1e+8
SO
2
OC
S
CO
2
Ar
H2S
N2 Ne
H2O
He
Kr
=> 0
.4 c
ount
s/se
c at
84
amu
Xe
=> 0
.02
coun
ts/s
ec a
t 129
am
u
Pred
icte
d si
gnal
with
dir
ect s
ampl
ing
at V
enus
with
no
enri
chm
ent o
r sa
tura
tion
of C
O2
Dyn
amic
ran
ge p
ossi
ble
with
smal
l qua
drup
ole
mas
s spe
ctro
met
er
Gal
ileo
Prob
e us
e en
rich
men
t but
NO
T st
atic
MS
Enr
ichm
ent t
echn
ique
s –th
e G
alile
o Pr
obe
Neu
tral
Mas
s Sp
ectr
omet
er a
ppro
ach
mas
s (a
mu)
124
126
128
130
132
134
136
ratio to nonradiogenic terrestrial
0.00
0.25
0.50
0.75
1.00
1.25
1.50
Xen
on
Iso
top
ic F
ract
ion
atio
n a
t Ju
pit
erfr
om
th
e G
alile
o P
rob
e M
ass
Sp
ectr
om
eter
Jovi
an x
enon
CI
chon
drit
esU
-Xe
[Pep
in, 1
992]
A p
ropo
sed
mea
sure
men
t pro
toco
l for
Ven
us n
oble
gas
and
15N
/14N
mea
sure
men
t•s
ampl
e a
volu
me
of V
enus
atm
osph
eric
gas
•che
mic
ally
rem
ove
CO
2as
gas
is sa
mpl
ed(f
or e
xam
ple,
CaO
(s) +
CO
2(g)
C
aCO
3(s
)•(
15N
14N
)/14N
2w
ith d
ynam
ic M
S to
obt
ain
15N
/14N
•che
mic
ally
rem
ove
N2
and
othe
r act
ive
gase
s with
a g
ette
r•c
ryog
enic
ally
rem
ove
Kr a
nd X
e (o
n hi
gh su
rfac
e ar
ea tr
ap)
•38A
r/36A
r and
36A
r/40A
r with
stat
ic M
S •c
ryog
enic
ally
rem
ove
Ar
•res
idua
l 20N
e/22
Ne
and
21N
e/22
Ne
and
3 He/
4 He
with
stat
ic M
S•r
elea
se K
r and
Xe
•all
Kr a
nd X
e is
otop
es
with
stat
ic M
S
F
Ar
trap
Kr,
Xe
trapPS
chem
ical
gette
rCO
tr
ap2
capi
llary
leak
JT C
oole
r
gas i
nlet
proc
esse
d ga
s tra
nsfe
red
to st
atic
or d
ynam
ic M
S
gas s
epar
atio
n sy
stem
Mot
ivat
ion
for
trac
e ga
s mea
sure
men
ts a
t Ven
us
Ver
tical
pro
files
thro
ugh
the
clou
ds a
nd d
own
to th
e su
rfac
e en
able
clo
ud c
hem
istr
y an
d at
mos
pher
e/su
rfac
e in
tera
ctio
ns to
be
stud
ied
S cy
cle
-B. F
egle
y et
al.,
in V
enus
II, U
. AZ
Pres
s, 61
8 (1
997)
(fol
low
ing
van
Zahn
& P
rinn)
.
anhy
drite
pyrit
em
agne
tite
hem
atite
pyrr
hotit
eFe
ldsp
arD
iops
ide
Cal
cite
Gas
es a
nd r
eact
ions
exp
ecte
d to
be
impo
rtan
t for
clo
ud c
hem
istr
y
SO2,
H2O
, SO
3, S
O, O
CS
SO2
+ ½
O2
+ H
2O +
M
H2S
O4
net r
eact
ion
Phot
olys
is o
f SO
2SO
+ O
Ele
men
tal s
ulfu
rSO
+ S
O
SO2
+ S
S +
S +
M
S 2+
MS 2
+ S 2
+ M
S 4
+ M
S 4+
S 4+
M
S 8+
M
Oth
er p
ossi
ble
spec
ies
NO
, Cl 2,
S2C
l 2et
c
Rea
ctio
ns th
at m
ay b
e im
port
ant f
or su
rfac
e/at
mos
pher
e in
tera
ctio
nV
olca
noes
like
ly so
urce
of S
O2
Wea
ther
ing
of su
rfac
e m
iner
als m
ay b
uffe
r atm
osph
eric
gas
es
Trac
e sp
ecie
s of i
nter
est t
hat r
efle
ct th
e ox
idat
ion
stat
e ne
ar th
e su
rfac
eH
2S, S
O2,
OC
S, O
2, C
O, H
2O
CaC
O3(
s) +
SO
2(g)
C
aSO
4(s)
+ C
O(g
)C
alci
te
anh
ydrit
e(ti
me
cons
tant
~ 2
M y
r –Fe
gley
& P
rinn,
198
9)
CaC
O3
(s) +
SiO
2(s
) = C
aSiO
3(s
) + C
O2
(g)
Cal
cite
quar
tz
w
olla
ston
ite(s
ourc
e of
cal
cite
–Fe
gley
& T
reim
an, 1
992)
Oxi
datio
n st
ate
dete
rmin
es F
e m
iner
alog
yFe
3O4(
s) +
O2
= Fe
2O3
(s)
mag
netit
e
h
emat
ite
Past
and
futu
re V
enus
mas
s spe
ctro
met
er
expe
rim
ents
Nee
d to
add
ress
the
diff
icul
t sam
plin
g is
sues
Sam
plin
g is
sues
•4 o
rder
s of m
agni
tude
pres
sure
diff
eren
tial
on tr
ack
from
abo
ve
clou
ds to
surf
ace
•tra
ce sp
ecie
s mea
sure
d to
pa
rts p
er b
illio
n•9
ord
ers o
f mag
nitu
de
diff
eren
ce b
etw
een
atm
osph
eric
pre
ssur
e at
su
rfac
e an
d io
n so
urce
pr
essu
re in
mas
s sp
ectro
met
er•5
00 d
egre
e te
mpe
ratu
re
grad
ient
from
atm
osph
ere
abov
e cl
ouds
to su
rfac
e•c
loud
dro
plet
s and
ae
roso
ls th
at c
an c
log
mas
s sp
ectro
met
er in
let s
yste
ms
and
mas
k re
al v
ertic
al
varia
tions
due
to th
eir
cond
ensa
tion
on su
rfac
es
Mis
sion
(Tea
m,
Dat
e)
Mas
s Sp
ectr
ome
ter
Alti
tude
(P
ress
ure)
In
let t
ype
Out
com
e
Ven
era
9 &
10
(Sur
kov,
von
Za
hn, 1
975)
mon
opol
e 63
-34
km
(130
mba
r to
6 b
ar
3 po
rous
pl
ugs
inst
rum
ent m
easu
red
prim
arily
ba
ckgr
ound
sign
al th
roug
hout
de
scen
t PV
-Lar
ge P
robe
(H
offm
an, 1
978)
m
agne
tic
sect
or
62 k
m to
su
rface
pi
nche
d Ta
tu
be (3
inle
ts)
50 k
m to
29
km in
let w
as b
lock
ed
and
inst
rum
ent m
easu
red
outg
assin
g fro
m H
2SO
4 dro
plet
s V
ener
a 11
& 1
2 La
nder
(Gre
chne
v,
1978
)
Benn
ett R
F 23
km
to
surfa
ce
1 m
x 5
mm
in
let p
ipe
&
pulse
d m
icro
valv
e
poss
ible
inle
t tub
e m
emor
y ef
fect
s, A
r iso
tope
s in
"sta
tic" m
ode,
Kr
dete
cted
but
isot
opes
NO
T re
solv
ed
PV-O
rbite
r (N
iem
ann,
K
aspr
zak,
197
8-19
92)
Qua
drup
ole
MS
orbi
ter
(upp
er
atm
osph
ere)
sour
ce o
pen
to a
mbi
ent
14 y
ears
of d
ata
neut
ral s
cale
he
ight
s (C
O+,
CO
, N2,
O, N
, and
He)
O
esc
ape
(ther
mos
pher
ic
mea
sure
men
ts g
ave
no in
form
atio
n on
hea
vy n
oble
gas
isot
opes
) PV
-Mul
tipro
be
Bus (
von
Zahn
, 19
78)
Mag
netic
Se
ctor
en
try to
0.
01 m
bar
open
with
di
ffere
ntia
l P
entry
mea
sure
men
ts (u
pper
lim
it on
36
Ar a
nd 40
Ar)
, ide
ntifi
ed H
e ho
mop
ause
at 1
37 k
m
Exa
mpl
e V
enus
mas
s spe
ctro
met
er e
xper
imen
ts
Atm
osph
eric
sam
plin
g ap
proa
ch•s
hort
inle
t lin
es h
eate
d ab
ove
ambi
ent t
o va
poriz
e co
nden
sate
s•c
hem
ical
ly in
ert m
ater
ials
in in
let
•ade
quat
e ae
roso
l tra
ps a
nd b
affle
s•m
ultip
le in
let l
eaks
•red
unda
nt in
let l
ines
TE
STT
EST
TE
STT
EST
The
futu
re o
f Ven
us e
xplo
ratio
n?•n
ear t
erm
obj
ectiv
es fr
om th
e pl
anet
ary
scie
nce
com
mun
ity a
re
clea
rly re
com
men
ded
to N
ASA
in th
e D
ecad
al S
tudy
Rep
ort
•the
pro
be/m
easu
rem
ent t
echn
olog
y is
re
ady
for n
oble
gas
and
trac
e sp
ecie
s m
easu
rem
ents
•NA
SA D
isco
very
& N
ew F
ront
ier
Mis
sion
s may
ena
ble
som
e of
thes
e re
com
men
datio
ns to
be
real
ized
•fut
ure
Ven
us d
etai
led
clou
d in
vest
igat
ions
, lon
g te
rm su
rfac
e pa
ckag
es a
nd sa
mpl
e re
turn
cle
arly
re
quire
adv
ance
d te
chno
logy
supp
ort
