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TACSAT Operations Phase
The TACSAT system is seen n phis paper
as supplementin strategic C P rcsources,
particularly w a ere communications
requirements peak or imaging data are
needed at short noiice. The oppoflunities
to use TACSATS to best effect can
thereforc only be recognised locally arid
should put into effect by a local Control
Centre.
The Control Centre must be able to assess
the effects of orbital manoeuvres, execd te
manoeuvre$ romptly aild quickly corafiim
the achieve. B new orbit. As has already
been said, speedy and accurate orbiit
determination can only be achieved with
long, ie out-of-Theatre, baselines.
Certainly for imaging missions, perigee
will be over the tactical theatre; for
communications missions this may also be
true.
The out-of-Theatre character of the
control function for some missions is
reinforced by the need to manoeuvre near
apogee, where manoeuvre fuel usage is
minimised and visibility to ground stations
is maximised. The Control Centre may
also have to call on spacecraft equipment
designers and test configurations to
resolve spacecraft performance
anomalies. All of this tends to suggest
that the res onsibility for TACSAT
Control coul B be assigned to a Military
S acecraft Control Centre supported byfa
P
gobal
tracking network but with rdn
excellent co-ordination interface t,o
in-Theatre tactical operations staff. This
latter requirement could be met b
assignment of several specialists (wii. l
recent spacecraft o erations experience)
to provide a 24- R our service at the
Tactical HQ. The Conuol Centre used
during the earlier Phases could be used ta
execute spacecraft control. However, a
knowledge-based system located
in-Theatre is likely to provide faster
response and more consistent operations,
This could be automated to minimise the
number of operations staff and provide
consistency during 24-hour operations. It
would consist of the following elemcnts:
Automated Mission Builds timeline
Planning options
Automated Library of Flight
Operations Control Plans,
Planning including Anomaly
Contingency Plans.
Computer Assisted Executes actual
Operations control via Tracking
Stations.
Adaptive Training Creates and
evalua: zs training
sessions.
Network Control is also required in the
case of a TACSAT communications
mission. It can be assumed that the
communications transponder will be
accessed only by in-Theatre force
elements, using locally-assigned cyphers.
In order to provide communications
services compatible with the needs of
tactical End Users, the way in which the
network is managed and user access is
granted and controlled must involve a
minimum of "overhead" workload
imposed on the End User. This can ran e
from avoiding the need to point t a e
antenna on his terminal
simplicity of operation o
to a mem of
in the integrity of the system, and to its
ability to provide the services required.
Optimum use of the TACSAT capacity
will be most easily achieved by a mture
of frequency assignment and timeline
planning issued by in-Theatre signals
staff. Some tyges of TACSAT
store-and-forwar communications
mission will require quite complex
space/ground protocols which must be
transparent to the End User. Some
classes of TACSAT will provide ima er
or transponder configuration options t P iat
are selectable by ground command. The
in-p eatre specialist TACSAT operations
staff will be best equipped to make the
appropriate option selections, which could
be implemented either by a local
telecommand uplink or by a centralised
Control Centre. In the case of in-Theatre
jamming attacks, the former is likely to
provide a far more successful ECCM
response than the latter, provided it can
counter any enemy jamming of the
telecommmd uplink.
The final stage of the TACSAT support
will he disposal of the s acecraft, either
into 3 higher parking or E it or a burn-up
during re-entry. Once the in-Theme