<s>
Venera	B-Algorithm
4V-2	I-Algorithm
(	O
)	O
was	O
a	O
series	O
of	O
two	O
identical	O
spacecraft	O
sent	O
to	O
Venus	B-Application
by	O
the	O
Soviet	O
Union	O
,	O
consisting	O
of	O
Venera	O
15	O
and	O
Venera	O
16	O
.	O
</s>
<s>
Both	O
uncrewed	O
orbiters	O
were	O
to	O
map	O
the	O
surface	O
of	O
Venus	B-Application
using	O
high	O
resolution	O
imaging	O
systems	O
.	O
</s>
<s>
Venera	O
15	O
and	O
Venera	O
16	O
both	O
reached	O
Venus	B-Application
 '	O
orbit	O
(	O
on	O
October	O
10	O
,	O
1983	O
,	O
and	O
October	O
14	O
,	O
1983	O
,	O
respectively	O
)	O
.	O
</s>
<s>
The	O
two	O
spacecraft	O
were	O
inserted	O
into	O
Venus	B-Application
orbit	O
a	O
day	O
apart	O
with	O
their	O
orbital	O
planes	O
shifted	O
by	O
an	O
angle	O
of	O
approximately	O
4°	O
relative	O
to	O
one	O
another	O
.	O
</s>
<s>
In	O
June	O
1984	O
,	O
Venus	B-Application
was	O
at	O
superior	O
conjunction	O
and	O
passed	O
behind	O
the	O
Sun	O
as	O
seen	O
from	O
Earth	O
.	O
</s>
<s>
25%	O
of	O
Venus	B-Application
surface	O
)	O
over	O
the	O
8	O
months	O
of	O
mapping	O
operations	O
.	O
</s>
<s>
The	O
Venera	B-Algorithm
15	I-Algorithm
and	I-Algorithm
16	I-Algorithm
spacecraft	O
were	O
identical	O
and	O
were	O
based	O
on	O
modifications	O
to	O
the	O
orbiter	O
portions	O
of	O
the	O
Venera	O
9	O
and	O
Venera	O
14	O
probes	O
.	O
</s>
<s>
Each	O
spacecraft	O
consisted	O
of	O
a	O
5	O
m	O
long	O
cylinder	O
with	O
a	O
0.6	O
m	O
diameter	O
,	O
1.4	O
m	O
tall	O
parabolic	O
dish	O
antenna	O
for	O
the	O
synthetic	O
aperture	O
radar	B-Application
(	O
SAR	O
)	O
at	O
one	O
end	O
.	O
</s>
<s>
Both	O
Venera	B-Algorithm
15	I-Algorithm
and	I-Algorithm
16	I-Algorithm
were	O
equipped	O
with	O
a	O
Synthetic	O
Aperture	O
Radar	B-Application
(	O
SAR	O
)	O
.	O
</s>
<s>
A	O
radar	B-Application
was	O
necessary	O
in	O
this	O
mission	O
because	O
nothing	O
else	O
would	O
be	O
able	O
to	O
penetrate	O
the	O
dense	O
clouds	O
of	O
Venus	B-Application
.	O
</s>
