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8-4
specific tools for each main arcas of cngincering
design arc shown. They can be concurredy call
on demand by the different experts working in
parallel for trade off or validation on diflcrent
fields : clcctrical, thermal, mechanical , orbit
environment, attitudc and orbit contrbl,
dynamic , propulsion, payload accomodatidn,
mission; satellite programmation, ctc ...
i
Presently, SYSTEMA is uscd primarily in thc
first part of the developmcnt process (fig 4).
from phase A proposals, mission and s.\tclli!c
layout tradc-offs to the end of ph?, * L with
dctailcd satellite design optimisation . VI' up to
proposals for a phase C activity. I
If additional risks causcd by eventual flaws rjr
bugs in numerical simulations arc acccptcd -
these risks arc assumed to bc affordable far
small tactical satellites with not vcly
sophisticatcd missions -, phase C validation tjy
mcans of such concurrcnt engiiieering only tools
would saw not only thc major portion of the
environmcntal tcsts costs (thcrmal, kacuum. suh,
vibrations) but also would rcducc thc schcdulc
induced costs.
Such an approach has dcmonstratcd its
cfficicncy through thc SSOT prograinmc (fig 5).
S80T is a microsatellite launchcd this sunimcr
as a conipanion of TOPEX - POSEIDON
SPACFCRAR on ARIANE. SSOT has
bcncfitcd from an intcnsivc use of SYSTEMA
from thc first stage of dcsign to the dclivcry ;it
the launch sitc. A programme conducted in a
very short timc for a very competitive cost.
I CONCLUSION 1
The approch prcscnted above is far from a
rcvolution. It is only an evolution.
To be efficient suck concurrcnt engineering
tools need to be validatcd and calibrated by
refcrcncc to the data gathered during previous
dcvclopmenl tcsts or during in orbit monitoring
of opcrational spacccrarts. In that sense such an
approach capitaliscs the whole cxpcrience
acquircd by MATRA MARCONI SPACE
through prcvious or currcnt low earth orbit
programmes : SPOT 1,2,3 - ERS 1 and 2,
HELIOS - SPOT 4 and Polar Platform.
The SYSTEM\ usc built-in flexibility givcs thc
opportunity to quickly update a current design
and thus allows to follow cvolutions of
technologics or accomodatc a newly availablc
equipmcnt.
SYSTEMA ;~llows a short rcaction timc and a
quick acconiodntion on the satcllitc as soon as
cmcrging rcquircmcnts arc formulated by the
uscrs.
~ll~iisimiiotts
Jw rhis Seciion appear immediaiely
afim ilte Fmrc~lt mnshiion.)
i.