one. le can't afford to

flool around during that phase
Mr. Murphy said. ''The-extra
cost of the second comouter,

compared to what we'd lose,

is probably less than 1% its
insurance,"
Anik is a squat cylinder

12 feet high with a diameter
of six feet, crowned by a
parabolic antenna. It will
be spun like a top, at 100
revolutions per minute to
Stabilize it and maintain
attitude, or nosition, in
space, The antenna will be
despun - counter-rotated by
an electric motor - so it
will point toward earth rath-
er than rotatina its beam
like a liahthouse.

‘hen the satellite is in
orbit, Telesat hopes to keep
it within a tenth.of a deaq-
ree, or 40 miles, of its all-
otted position. Solar ore-
ssures, the drag of the de-
spun antenna and other fact-
ors will cause Anik to drift
from its optimum location
and attitude, so thrusters
will be fired every 19 to
14 days to maintain the snin
rate and keen Anik within
the 40 mile houndary.

The electronics in the
snacecraft will normally be
powered by the solar cells,
but twice yearly for about
two weeks, Anik will daily
exnerience solar,eclipses,
during which batteries will
be used to maintain vower.
These eclipses last froma
few minutes to a maximum of
70 minutes a day.

About 23,000 solar cells
cover Anik's cylindrical
frame. This is not the most
efficient way to deploy them,
since nearly half face away
from the sun at a aiven
time, but other methods re-
quire sophisticated and ex-
pensive stabilization equip-
ment.

lf all qoes well with Arik
in tlovember, a sister sate-
Tlite will be Jaunched four

its

to six months later, solely
as a backun to the vrimary
system [It will be located
at 109 deaqrees west lonait-
ude, about 2,000 miles from
Anik,

Mr. Murphy said satellites
emittina sianals on the same
frequency should not he
closer than 2,990 miles in
synchronous orbit. "But if
they have different frequen-
cies, you can qet a smaller
interval with no interference!

There had been some thought
about keeping the second
satellite on the qround, but
he said "this doesn't satisfy

a commercial customer,!! |
The CBC for example, plans

- to use the satellite almost

exclusively and cannot aff-
ord to wait for another

launch if Anik suddenly aoes
out. "Our customers are not
prepared to acquiese to the
delay required if somethina

goes wrong, Nobody accepts

that kind of risk.'' Mr,
Murphy said.

Anik will beam its sianal
to snecial around stations,
most of which are in the
North. There will be two main
Stations for both sendina
and receivina sionals; one
at Allan Park, 70 miles nor-
thwest of Toronto, and the
other at lake Cowichan on
Vancouver Island,

COMMAND FACILITY

Allan Park is also the
satellite command facility. ©
It has a fully steerable 32
foot antenna to acquire and
track the satellite, tran-
smit. the sianal to fire the
apogee motor and ferry infor-
mation on international
systems between Anik and the
control centre in Ottawa.

The control centre has a
full-time staff of about 25,
with four or five people on
duty around the clock.

Allan Park has a second
larger antenna to send and

5

receive the communications
stanals - TV and telenhone
messanes. This antenna will
eventually take over command
resnonsibility for Anik as
well, when the 32-foot ant-
enna is needed for the sec-
ond satellite.

The Lake Cowichan facility
is the other major send-rec-
eive station. In addition,
six network quality stations
in Edmonton, Reaqina, Winni-
pea, St. John's and Halifax
will receive and transmit TY
sianals. The Montreal station
will provide French=lanquaqe
programmina for the rest of
the country.

Some 24 remote TV stations
will be scattered throuahout
the North to vrovide tele-
vision to areas not currently
serviced by microwave fac-
ilities. Many northern com
munities now have television
videotape flown in. These
northern stations will only
be able to receive televis-
ion sianals initially but
they can be uparaded to re-
ceive and transmit both TY
and messaqe sianals.

Two northern telecommuni-
cations facilities at Frob-
isher Bay and Resolute Bay,
will establish two-way links
between the tlorth and the
east-west telecommunications
network operating in south-
ern Canada. Roth stations
receive and transmit mess-
aqes and Frobisher will re-
ceive one TV channel.

Smaller and simpler sta-
tions for telephone and
radio links are also beina
considered for other north-
ern locations,

The earth stations have
all been desianed to be
upaqraded with relatively
small incremental expense,

The furture confiauration
of the satellite system
itself is less well defined
at the present time. Mr,
Murphy said Telesat has
option to buy more Anik-

an