<s>
The	O
Magellan	B-Architecture
spacecraft	I-Architecture
was	O
a	O
robotic	O
space	O
probe	O
launched	O
by	O
NASA	O
of	O
the	O
United	O
States	O
,	O
on	O
May	O
4	O
,	O
1989	O
,	O
to	O
map	O
the	O
surface	O
of	O
Venus	B-Application
by	O
using	O
synthetic-aperture	B-Application
radar	I-Application
and	O
to	O
measure	O
the	O
planetary	O
gravitational	O
field	O
.	O
</s>
<s>
The	O
Magellan	B-Architecture
probe	I-Architecture
was	O
the	O
first	O
interplanetary	O
mission	O
to	O
be	O
launched	O
from	O
the	O
Space	O
Shuttle	O
,	O
the	O
first	O
one	O
to	O
use	O
the	O
Inertial	O
Upper	O
Stage	O
booster	O
,	O
and	O
the	O
first	O
spacecraft	O
to	O
test	O
aerobraking	O
as	O
a	O
method	O
for	O
circularizing	O
its	O
orbit	O
.	O
</s>
<s>
Magellan	B-Architecture
was	O
the	O
fifth	O
successful	O
NASA	O
mission	O
to	O
Venus	B-Application
,	O
and	O
it	O
ended	O
an	O
eleven-year	O
gap	O
in	O
U.S.	O
interplanetary	O
probe	O
launches	O
.	O
</s>
<s>
Beginning	O
in	O
the	O
late	O
1970s	O
,	O
scientists	O
advocated	O
for	O
a	O
radar	B-Application
mapping	I-Application
mission	O
to	O
Venus	B-Application
.	O
</s>
<s>
They	O
first	O
sought	O
to	O
construct	O
a	O
spacecraft	O
named	O
the	O
Venus	B-Application
Orbiting	O
Imaging	O
Radar	B-Application
(	O
VOIR	O
)	O
,	O
but	O
it	O
became	O
clear	O
that	O
the	O
mission	O
would	O
be	O
beyond	O
the	O
budget	O
constraints	O
during	O
the	O
ensuing	O
years	O
.	O
</s>
<s>
A	O
simplified	O
radar	B-Application
mission	O
proposal	O
was	O
recommended	O
by	O
the	O
Solar	O
System	O
Exploration	O
Committee	O
,	O
and	O
this	O
one	O
was	O
submitted	O
and	O
accepted	O
as	O
the	O
Venus	B-Architecture
Radar	I-Architecture
Mapper	I-Architecture
program	O
in	O
1983	O
.	O
</s>
<s>
In	O
1985	O
,	O
the	O
mission	O
was	O
renamed	O
Magellan	B-Architecture
,	O
in	O
honor	O
of	O
the	O
sixteenth-century	O
Portuguese	O
explorer	O
Ferdinand	O
Magellan	B-Architecture
,	O
known	O
for	O
his	O
exploration	O
,	O
mapping	O
,	O
and	O
circumnavigation	O
of	O
the	O
Earth	O
.	O
</s>
<s>
Obtain	O
near-global	O
radar	B-Application
images	O
of	O
the	O
Venusian	O
surface	O
with	O
a	O
resolution	O
equivalent	O
to	O
optical	O
imaging	O
of	O
per	O
line	O
pair	O
.	O
</s>
<s>
For	O
JPL	O
,	O
Douglas	O
Griffith	O
served	O
as	O
the	O
Magellan	B-Architecture
project	O
manager	O
and	O
R	O
.	O
Stephen	O
Saunders	O
served	O
as	O
the	O
lead	O
project	O
scientist	O
.	O
</s>
<s>
Hughes	O
Aircraft	O
Company	O
's	O
Space	O
and	O
Communications	O
Group	O
designed	O
and	O
built	O
the	O
spacecraft	O
's	O
synthetic	B-Application
aperture	I-Application
radar	I-Application
.	O
</s>
<s>
To	O
save	O
costs	O
,	O
most	O
of	O
the	O
Magellan	B-Architecture
probe	I-Architecture
was	O
made	O
up	O
of	O
flight	O
spare	O
parts	O
and	O
reused	O
design	O
elements	O
from	O
other	O
spacecraft	O
:	O
</s>
<s>
The	O
spacecraft	O
's	O
attitude	O
control	O
(	O
orientation	O
)	O
was	O
designed	O
to	O
be	O
three-axis	O
stabilized	O
,	O
including	O
during	O
the	O
firing	O
of	O
the	O
Star	O
48B	O
solid	O
rocket	O
motor	O
(	O
SRM	O
)	O
used	O
to	O
place	O
it	O
into	O
orbit	O
around	O
Venus	B-Application
.	O
</s>
<s>
Prior	O
to	O
Magellan	B-Architecture
,	O
all	O
spacecraft	O
SRM	O
firings	O
had	O
involved	O
spinning	O
spacecraft	O
,	O
which	O
made	O
control	O
of	O
the	O
SRM	O
a	O
much	O
easier	O
task	O
.	O
</s>
<s>
In	O
the	O
case	O
of	O
Magellan	B-Architecture
,	O
the	O
spacecraft	O
design	O
did	O
not	O
lend	O
itself	O
to	O
spinning	O
,	O
so	O
the	O
resulting	O
propulsion	O
system	O
design	O
had	O
to	O
accommodate	O
the	O
challenging	O
control	O
issues	O
with	O
the	O
large	O
Star	O
48B	O
SRM	O
.	O
</s>
<s>
The	O
design	O
also	O
included	O
a	O
pyrotechnically-isolated	O
external	O
high	O
pressure	O
tank	O
with	O
additional	O
helium	O
that	O
could	O
be	O
connected	O
to	O
the	O
main	O
tank	O
prior	O
to	O
the	O
critical	O
Venus	B-Application
orbit	O
insertion	O
burn	O
to	O
ensure	O
maximum	O
thrust	O
from	O
the	O
445	O
N	O
thrusters	O
during	O
the	O
SRM	O
firing	O
.	O
</s>
<s>
When	O
communicating	O
with	O
the	O
Deep	O
Space	O
Network	O
,	O
the	O
spacecraft	O
was	O
able	O
to	O
simultaneously	O
receive	O
commands	O
at	O
1.2	O
kilobits/second	O
in	O
the	O
S-band	B-Algorithm
and	O
transmit	O
data	O
at	O
268.8	O
kilobits/second	O
in	O
the	O
X-band	B-Algorithm
.	O
</s>
<s>
Magellan	B-Architecture
was	O
powered	O
by	O
two	O
square	O
solar	O
arrays	O
,	O
each	O
measuring	O
2.5	O
meters	O
across	O
.	O
</s>
<s>
There	O
were	O
two	O
ATAC-16	O
computers	O
forming	O
one	O
redundant	O
system	O
,	O
located	O
in	O
the	O
attitude-control	O
subsystem	O
,	O
and	O
four	O
RCA	B-General_Concept
1802	I-General_Concept
microprocessors	O
,	O
as	O
two	O
redundant	O
systems	O
,	O
to	O
control	O
the	O
command	O
and	O
data	O
subsystem	O
(	O
CDS	O
)	O
.	O
</s>
<s>
Thick	O
and	O
opaque	O
,	O
the	O
atmosphere	O
of	O
Venus	B-Application
required	O
a	O
method	O
beyond	O
optical	O
survey	O
,	O
to	O
map	O
the	O
surface	O
of	O
the	O
planet	O
.	O
</s>
<s>
The	O
resolution	O
of	O
conventional	O
radar	B-Application
depends	O
entirely	O
on	O
the	O
size	O
of	O
the	O
antenna	O
,	O
which	O
is	O
greatly	O
restricted	O
by	O
costs	O
,	O
physical	O
constraints	O
by	O
launch	O
vehicles	O
and	O
the	O
complexity	O
of	O
maneuvering	O
a	O
large	O
apparatus	O
to	O
provide	O
high	O
resolution	O
data	O
.	O
</s>
<s>
Magellan	B-Architecture
addressed	O
this	O
problem	O
by	O
using	O
a	O
method	O
known	O
as	O
synthetic	B-Application
aperture	I-Application
,	O
where	O
a	O
large	O
antenna	O
is	O
imitated	O
by	O
processing	O
the	O
information	O
gathered	O
by	O
ground	O
computers	O
.	O
</s>
<s>
The	O
Magellan	B-Architecture
high-gain	O
parabolic	O
antenna	O
,	O
oriented	O
28°	O
–	O
78°	O
to	O
the	O
right	O
or	O
left	O
of	O
nadir	O
,	O
emitted	O
thousands	O
of	O
microwave	O
pulses	O
per	O
second	O
that	O
passed	O
through	O
the	O
clouds	O
and	O
to	O
the	O
surface	O
of	O
Venus	B-Application
,	O
illuminating	O
a	O
swath	O
of	O
land	O
.	O
</s>
<s>
The	O
Radar	B-Application
System	I-Application
then	O
recorded	O
the	O
brightness	O
of	O
each	O
pulse	O
as	O
it	O
reflected	O
back	O
off	O
the	O
side	O
surfaces	O
of	O
rocks	O
,	O
cliffs	O
,	O
volcanoes	O
and	O
other	O
geologic	O
features	O
,	O
as	O
a	O
form	O
of	O
backscatter	B-Algorithm
.	O
</s>
<s>
To	O
increase	O
the	O
imaging	O
resolution	O
,	O
Magellan	B-Architecture
recorded	O
a	O
series	O
of	O
data	O
bursts	O
for	O
a	O
particular	O
location	O
during	O
multiple	O
instances	O
called	O
,	O
"	O
looks	O
"	O
.	O
</s>
<s>
The	O
Radar	B-Application
System	I-Application
functioned	O
in	O
three	O
modes	O
:	O
synthetic	B-Application
aperture	I-Application
radar	I-Application
(	O
SAR	O
)	O
,	O
altimetry	O
(	O
ALT	O
)	O
,	O
and	O
radiometry	O
(	O
RAD	O
)	O
.	O
</s>
<s>
The	O
instrument	O
cycled	O
through	O
the	O
three	O
modes	O
while	O
observing	O
the	O
surface	O
geology	O
,	O
topography	O
,	O
and	O
temperature	O
of	O
Venus	B-Application
using	O
the	O
3.7-meter	O
parabolic	O
,	O
high-gain	O
antenna	O
and	O
a	O
small	O
fan-beam	O
antenna	O
,	O
located	O
just	O
to	O
the	O
side	O
.	O
</s>
<s>
–	O
In	O
the	O
Synthetic	B-Application
Aperture	I-Application
Radar	I-Application
mode	O
,	O
the	O
instrument	O
transmitted	O
several	O
thousand	O
long-wave	O
,	O
12.6-centimeter	O
microwave	O
pulses	O
every	O
second	O
through	O
the	O
high-gain	O
antenna	O
,	O
while	O
measuring	O
the	O
doppler	O
shift	O
of	O
each	O
hitting	O
the	O
surface	O
.	O
</s>
<s>
–	O
In	O
Altimetry	O
mode	O
,	O
the	O
instrument	O
interleaved	O
pulses	O
with	O
SAR	O
,	O
and	O
operating	O
similarly	O
with	O
the	O
altimetric	O
antenna	O
,	O
recording	O
information	O
regarding	O
the	O
elevation	O
of	O
the	O
surface	O
on	O
Venus	B-Application
.	O
</s>
<s>
–	O
In	O
Radiometry	O
mode	O
,	O
the	O
high-gain	O
antenna	O
was	O
used	O
to	O
record	O
microwave	O
radiothermal	O
emissions	O
from	O
Venus	B-Application
.	O
</s>
<s>
The	O
data	O
was	O
collected	O
at	O
750	O
kilobits/second	O
to	O
the	O
tape	O
recorder	O
and	O
later	O
transmitted	O
to	O
Earth	O
to	O
be	O
processed	O
into	O
usable	O
images	O
,	O
by	O
the	O
Radar	B-Application
Data	O
Processing	O
Subsystem	O
(	O
RDPS	O
)	O
,	O
a	O
collection	O
of	O
ground	O
computers	O
operated	O
by	O
JPL	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
radar	B-Application
data	O
,	O
Magellan	B-Architecture
collected	O
several	O
other	O
types	O
of	O
scientific	O
measurements	O
.	O
</s>
<s>
These	O
included	O
detailed	O
measurements	O
of	O
the	O
Venus	B-Application
gravitational	O
field	O
,	O
measurements	O
of	O
the	O
atmospheric	O
density	O
,	O
and	O
radio	O
occultation	O
data	O
on	O
the	O
atmospheric	O
profile	O
.	O
</s>
<s>
Begin	O
Venus	B-Application
primary	O
mission	O
operations	O
Venus	B-Application
orbital	O
insertion	O
maneuver	O
Begin	O
mapping	O
cycle	O
1	O
Phase	O
stop	O
Begin	O
Venus	B-Application
extended	O
mission	O
operations	O
Begin	O
mapping	O
cycle	O
2	O
Begin	O
mapping	O
cycle	O
3	O
Begin	O
mapping	O
cycle	O
4	O
Begin	O
testing	O
aerobraking	O
maneuver	O
to	O
place	O
Magellan	B-Architecture
into	O
an	O
almost	O
circular	O
orbit	O
.	O
</s>
<s>
Magellan	B-Architecture
was	O
launched	O
on	O
May	O
4	O
,	O
1989	O
,	O
at	O
18:46:59	O
UTC	O
by	O
the	O
National	O
Aeronautics	O
and	O
Space	O
Administration	O
from	O
KSC	O
Launch	O
Complex	O
39B	O
at	O
the	O
Kennedy	O
Space	O
Center	O
in	O
Florida	O
,	O
aboard	O
Space	O
Shuttle	O
Atlantis	O
during	O
mission	O
STS-30	O
.	O
</s>
<s>
Once	O
in	O
orbit	O
,	O
the	O
Magellan	B-Architecture
and	O
its	O
attached	O
Inertial	O
Upper	O
Stage	O
booster	O
were	O
deployed	O
from	O
Atlantis	O
and	O
launched	O
on	O
May	O
5	O
,	O
1989	O
01:06:00	O
UTC	O
,	O
sending	O
the	O
spacecraft	O
into	O
a	O
Type	O
IV	O
heliocentric	O
orbit	O
where	O
it	O
would	O
circle	O
the	O
Sun	O
1.5	O
times	O
,	O
before	O
reaching	O
Venus	B-Application
15	O
months	O
later	O
on	O
August	O
10	O
,	O
1990	O
.	O
</s>
<s>
Originally	O
,	O
the	O
Magellan	B-Architecture
had	O
been	O
scheduled	O
for	O
launch	O
in	O
1988	O
with	O
a	O
trajectory	O
lasting	O
six	O
months	O
.	O
</s>
<s>
However	O
,	O
due	O
to	O
the	O
Space	O
Shuttle	O
Challenger	O
disaster	O
in	O
1986	O
,	O
several	O
missions	O
,	O
including	O
Galileo	O
and	O
Magellan	B-Architecture
,	O
were	O
deferred	O
until	O
shuttle	O
flights	O
resumed	O
in	O
September	O
1988	O
.	O
</s>
<s>
Magellan	B-Architecture
was	O
planned	O
to	O
be	O
launched	O
with	O
a	O
liquid-fueled	O
,	O
Centaur	O
G	O
upper-stage	O
booster	O
,	O
carried	O
in	O
the	O
cargo	O
bay	O
of	O
the	O
Space	O
Shuttle	O
.	O
</s>
<s>
However	O
,	O
the	O
entire	O
Centaur	O
G	O
program	O
was	O
canceled	O
after	O
the	O
Challenger	O
disaster	O
,	O
and	O
the	O
Magellan	B-Architecture
probe	I-Architecture
had	O
to	O
be	O
modified	O
to	O
be	O
attached	O
to	O
the	O
less-powerful	O
Inertial	O
Upper	O
Stage	O
.	O
</s>
<s>
Further	O
complicating	O
the	O
launch	O
however	O
,	O
was	O
the	O
launching	O
of	O
the	O
Galileo	O
mission	O
to	O
Jupiter	O
,	O
one	O
that	O
included	O
a	O
fly-by	O
of	O
Venus	B-Application
.	O
</s>
<s>
Intended	O
for	O
launch	O
in	O
1986	O
,	O
the	O
pressures	O
to	O
ensure	O
a	O
launch	O
for	O
Galileo	O
in	O
1989	O
,	O
mixed	O
with	O
a	O
short	O
launch-window	O
necessitating	O
a	O
mid-October	O
launch	O
,	O
resulted	O
in	O
replanning	O
the	O
Magellan	B-Architecture
mission	O
.	O
</s>
<s>
Wary	O
of	O
rapid	O
shuttle	O
launches	O
,	O
the	O
decision	O
was	O
made	O
to	O
launch	O
Magellan	B-Architecture
in	O
May	O
,	O
and	O
into	O
an	O
orbit	O
that	O
would	O
require	O
one	O
year	O
,	O
three	O
months	O
,	O
before	O
encountering	O
Venus	B-Application
.	O
</s>
<s>
On	O
August	O
10	O
,	O
1990	O
,	O
Magellan	B-Architecture
encountered	O
Venus	B-Application
and	O
began	O
the	O
orbital	O
insertion	O
maneuver	O
which	O
placed	O
the	O
spacecraft	O
into	O
a	O
three-hour	O
,	O
nine	O
minute	O
,	O
elliptical	O
orbit	O
that	O
brought	O
the	O
spacecraft	O
295-kilometers	O
from	O
the	O
surface	O
at	O
about	O
10	O
degrees	O
North	O
during	O
the	O
periapsis	O
and	O
out	O
to	O
7762-kilometers	O
during	O
apoapsis	O
.	O
</s>
<s>
During	O
each	O
orbit	O
,	O
the	O
space	O
probe	O
captured	O
radar	B-Application
data	O
while	O
the	O
spacecraft	O
was	O
closest	O
to	O
the	O
surface	O
,	O
and	O
then	O
transmit	O
it	O
back	O
to	O
Earth	O
as	O
it	O
moved	O
away	O
from	O
Venus	B-Application
.	O
</s>
<s>
To	O
avoid	O
overly-redundant	O
data	O
at	O
the	O
highest	O
and	O
lowest	O
latitudes	O
,	O
the	O
Magellan	B-Architecture
probe	I-Architecture
alternated	O
between	O
a	O
Northern-swath	O
,	O
a	O
region	O
designated	O
as	O
90	O
degrees	O
north	O
latitude	O
to	O
54	O
degrees	O
south	O
latitude	O
,	O
and	O
a	O
Southern-swath	O
,	O
designated	O
as	O
76	O
degrees	O
north	O
latitude	O
to	O
68	O
degrees	O
south	O
latitude	O
.	O
</s>
<s>
The	O
primary	O
mission	O
began	O
on	O
September	O
15	O
,	O
1990	O
,	O
with	O
the	O
intention	O
to	O
provide	O
a	O
"	O
left-looking	O
"	O
map	O
of	O
70%	O
of	O
the	O
Venusian	O
surface	O
at	O
a	O
minimum	O
resolution	O
of	O
1-kilometer/pixel	O
.	O
</s>
<s>
Upon	O
completion	O
during	O
May	O
15	O
,	O
1991	O
,	O
having	O
made	O
1,792	O
orbits	O
,	O
Magellan	B-Architecture
had	O
mapped	O
approximately	O
83.7	O
%	O
of	O
the	O
surface	O
with	O
a	O
resolution	O
between	O
101	O
and	O
250-meters/pixel	O
.	O
</s>
<s>
To	O
do	O
this	O
,	O
Magellan	B-Architecture
had	O
to	O
be	O
reoriented	O
,	O
changing	O
the	O
gathering	O
method	O
to	O
"	O
right-looking	O
"	O
.	O
</s>
<s>
Goal	O
:	O
Measure	O
Venus	B-Application
 '	O
gravitational	O
field	O
.	O
</s>
<s>
Upon	O
completing	O
cycle	O
3	O
,	O
Magellan	B-Architecture
ceased	O
imaging	O
the	O
surface	O
.	O
</s>
<s>
Instead	O
,	O
beginning	O
mid-September	O
1992	O
,	O
the	O
Magellan	B-Architecture
maintained	O
pointing	O
of	O
the	O
high-gain	O
antenna	O
toward	O
Earth	O
where	O
the	O
Deep	O
Space	O
Network	O
began	O
recording	O
a	O
constant	O
stream	O
of	O
telemetry	O
.	O
</s>
<s>
This	O
constant	O
signal	O
allowed	O
the	O
DSN	O
to	O
collect	O
information	O
on	O
the	O
gravitational	O
field	O
of	O
Venus	B-Application
by	O
monitoring	O
the	O
velocity	O
of	O
the	O
spacecraft	O
.	O
</s>
<s>
At	O
the	O
end	O
of	O
the	O
fourth	O
cycle	O
in	O
May	O
1993	O
,	O
the	O
orbit	O
of	O
Magellan	B-Architecture
was	O
circularized	O
using	O
a	O
technique	O
known	O
as	O
aerobraking	O
.	O
</s>
<s>
Testing	O
a	O
new	O
approach	O
to	O
the	O
method	O
,	O
a	O
plan	O
was	O
devised	O
to	O
drop	O
the	O
orbit	O
of	O
Magellan	B-Architecture
into	O
the	O
outermost	O
region	O
of	O
the	O
Venusian	O
atmosphere	O
.	O
</s>
<s>
Toward	O
the	O
end	O
of	O
the	O
cycle	O
,	O
a	O
final	O
experiment	O
was	O
conducted	O
,	O
known	O
as	O
the	O
"	O
Windmill	O
"	O
experiment	O
to	O
provide	O
data	O
on	O
the	O
composition	O
of	O
the	O
upper	O
atmosphere	O
of	O
Venus	B-Application
.	O
</s>
<s>
Magellan	B-Architecture
performed	O
1,783	O
orbits	O
before	O
the	O
end	O
of	O
the	O
cycle	O
on	O
October	O
13	O
,	O
1994	O
,	O
when	O
the	O
spacecraft	O
entered	O
the	O
atmosphere	O
and	O
disintegrated	O
.	O
</s>
<s>
In	O
September	O
1994	O
,	O
the	O
orbit	O
of	O
Magellan	B-Architecture
was	O
lowered	O
to	O
begin	O
the	O
"	O
Windmill	O
experiment	O
"	O
.	O
</s>
<s>
Study	O
of	O
the	O
Magellan	B-Architecture
high-resolution	O
global	O
images	O
is	O
providing	O
evidence	O
to	O
better	O
understand	O
Venusian	O
geology	O
and	O
the	O
role	O
of	O
impacts	O
,	O
volcanism	O
,	O
and	O
tectonics	O
in	O
the	O
formation	O
of	O
Venusian	O
surface	O
structures	O
.	O
</s>
<s>
The	O
surface	O
of	O
Venus	B-Application
is	O
mostly	O
covered	O
by	O
volcanic	O
materials	O
.	O
</s>
<s>
There	O
are	O
few	O
impact	O
craters	O
on	O
Venus	B-Application
,	O
suggesting	O
that	O
the	O
surface	O
is	O
,	O
in	O
general	O
,	O
geologically	O
young	O
-	O
less	O
than	O
800	O
million	O
years	O
old	O
.	O
</s>
<s>
The	O
typical	O
signs	O
of	O
terrestrial	O
plate	O
tectonics	O
-	O
continental	O
drift	O
and	O
basin	O
floor	O
spreading	O
-	O
are	O
not	O
evident	O
on	O
Venus	B-Application
.	O
</s>
<s>
Although	O
Venus	B-Application
has	O
a	O
dense	O
atmosphere	O
,	O
the	O
surface	O
reveals	O
no	O
evidence	O
of	O
substantial	O
wind	O
erosion	O
,	O
and	O
only	O
evidence	O
of	O
limited	O
wind	O
transport	O
of	O
dust	O
and	O
sand	O
.	O
</s>
<s>
Magellan	B-Architecture
created	O
the	O
first	O
(	O
and	O
currently	O
the	O
best	O
)	O
near-photographic	O
quality	O
,	O
high	O
resolution	O
radar	B-Application
mapping	I-Application
of	O
the	O
planet	O
's	O
surface	O
features	O
.	O
</s>
<s>
Prior	O
Venus	B-Application
missions	O
had	O
created	O
low	O
resolution	O
radar	B-Application
globes	O
of	O
general	O
,	O
continent-sized	O
formations	O
.	O
</s>
<s>
Magellan	B-Architecture
,	O
however	O
,	O
finally	O
allowed	O
detailed	O
imaging	O
and	O
analysis	O
of	O
craters	O
,	O
hills	O
,	O
ridges	O
,	O
and	O
other	O
geologic	O
formations	O
,	O
to	O
a	O
degree	O
comparable	O
to	O
the	O
visible-light	O
photographic	O
mapping	O
of	O
other	O
planets	O
.	O
</s>
<s>
Magellan	B-Architecture
's	O
global	O
radar	B-Application
map	O
currently	O
remains	O
as	O
the	O
most	O
detailed	O
Venus	B-Application
map	O
in	O
existence	O
,	O
although	O
the	O
upcoming	O
NASA	O
VERITAS	O
and	O
Roskosmos	O
Venera-D	O
probes	O
will	O
carry	O
a	O
radar	B-Application
that	O
can	O
achieve	O
a	O
much	O
higher	O
resolution	O
compared	O
to	O
the	O
radar	B-Application
used	O
by	O
Magellan	B-Architecture
.	O
</s>
<s>
The	O
Magellan	B-Architecture
project	O
was	O
set	O
up	O
so	O
that	O
the	O
initial	O
images	O
and	O
data	O
from	O
the	O
Magellan	B-Architecture
probe	I-Architecture
were	O
only	O
for	O
use	O
and	O
study	O
by	O
a	O
team	O
of	O
principal	O
investigators	O
from	O
a	O
variety	O
of	O
universities	O
and	O
institutions	O
,	O
and	O
by	O
the	O
Magellan	B-Architecture
Project	O
Science	O
Team	O
.	O
</s>
<s>
Data	O
was	O
shared	O
with	O
three	O
visiting	O
Soviet	O
scientists	O
(	O
Alexander	O
Basilevsky	O
,	O
Effaim	O
Akim	O
and	O
Alexander	O
Zacharov	O
)	O
,	O
a	O
first	O
,	O
and	O
sensitive	O
issue	O
,	O
for	O
NASA	O
at	O
the	O
time	O
considering	O
the	O
Cold	B-Application
War	I-Application
was	O
just	O
coming	O
to	O
a	O
close	O
.	O
</s>
<s>
The	O
Magellan	B-Architecture
Project	O
Science	O
room	O
became	O
notorious	O
for	O
its	O
hanging	O
of	O
long	O
thermal	O
print	O
strips	O
of	O
image	O
data	O
(	O
FBIDRs	O
)	O
along	O
the	O
walls	O
of	O
a	O
spacious	O
room	O
.	O
</s>
<s>
This	O
was	O
the	O
first	O
form	O
in	O
which	O
the	O
imagery	O
of	O
the	O
surface	O
of	O
Venus	B-Application
was	O
seen	O
due	O
to	O
the	O
long	O
,	O
narrow	O
swathes	O
acquired	O
by	O
the	O
spacecraft	O
.	O
</s>
<s>
After	O
the	O
initial	O
investigation	O
stage	O
Magellan	B-Architecture
's	O
full	O
data	O
set	O
was	O
released	O
for	O
public	O
consumption	O
.	O
</s>
<s>
The	O
Magellan	B-Architecture
Project	O
Science	O
Team	O
consisted	O
of	O
Dr.	O
R	O
.	O
Stephen	O
Saunders	O
,	O
the	O
Project	O
Scientist	O
;	O
Dr.	O
Ellen	O
Stofan	O
,	O
the	O
Deputy	O
Project	O
Scientist	O
;	O
research	O
assistants	O
Tim	O
Parker	O
,	O
Dr.	O
Jeff	O
Plaut	O
,	O
and	O
Annette	O
deCharon	O
;	O
and	O
Project	O
Science	O
Aide	O
,	O
Gregory	O
Michaels	O
.	O
</s>
<s>
Other	O
Magellan	B-Architecture
scientists	O
were	O
involved	O
with	O
the	O
mission	O
's	O
science	O
including	O
principal	O
investigators	O
and	O
three	O
visiting	O
Soviet	O
scientists	O
.	O
</s>
<s>
On	O
September	O
9	O
,	O
1994	O
,	O
a	O
press	O
release	O
outlined	O
the	O
termination	O
of	O
the	O
Magellan	B-Architecture
mission	O
.	O
</s>
<s>
On	O
October	O
13	O
,	O
1994	O
at	O
10:05:00	O
UTC	O
,	O
communication	O
was	O
lost	O
when	O
the	O
spacecraft	O
entered	O
radio	O
occultation	O
behind	O
Venus	B-Application
.	O
</s>
<s>
Although	O
much	O
of	O
Magellan	B-Architecture
was	O
expected	O
to	O
vaporize	O
due	O
to	O
atmospheric	O
stresses	O
,	O
some	O
amount	O
of	O
wreckage	O
is	O
thought	O
have	O
hit	O
the	O
surface	O
by	O
20:00:00	O
UTC	O
.	O
</s>
<s>
Communication	O
with	O
the	O
Magellan	B-Architecture
spacecraft	I-Architecture
was	O
lost	O
early	O
Wednesday	O
morning	O
,	O
following	O
an	O
aggressive	O
series	O
of	O
five	O
Orbit	O
Trim	O
Maneuvers	O
(	O
OTMs	O
)	O
on	O
Tuesday	O
,	O
October	O
11	O
,	O
which	O
took	O
the	O
orbit	O
down	O
into	O
the	O
upper	O
atmosphere	O
of	O
Venus	B-Application
.	O
</s>
<s>
Magellan	B-Architecture
continued	O
to	O
maintain	O
communication	O
for	O
three	O
more	O
orbits	O
,	O
even	O
though	O
the	O
power	O
continued	O
to	O
drop	O
below	O
23	O
volts	O
and	O
eventually	O
reached	O
20.4	O
volts	O
.	O
</s>
<s>
Communication	O
was	O
lost	O
at	O
3:02	O
am	O
PDT	O
just	O
as	O
Magellan	B-Architecture
was	O
about	O
to	O
enter	O
an	O
Earth	O
occultation	O
on	O
orbit	O
15032	O
.	O
</s>
<s>
The	O
spacecraft	O
should	O
land	O
on	O
Venus	B-Application
by	O
1:00	O
pm	O
PDT	O
Thursday	O
,	O
October	O
13	O
,	O
1994	O
.	O
</s>
