Constraint programming for planning test campaigns of communications
  satellites
  The payload of communications satellites must go through a series of tests to
assert their ability to survive in space. Each test involves some equipment of
the payload to be active, which has an impact on the temperature of the
payload. Sequencing these tests in a way that ensures the thermal stability of
the payload and minimizes the overall duration of the test campaign is a very
important objective for satellite manufacturers. The problem can be decomposed
in two sub-problems corresponding to two objectives: First, the number of
distinct configurations necessary to run the tests must be minimized. This can
be modeled as packing the tests into configurations, and we introduce a set of
implied constraints to improve the lower bound of the model. Second, tests must
be sequenced so that the number of times an equipment unit has to be switched
on or off is minimized. We model this aspect using the constraint Switch, where
a buffer with limited capacity represents the currently active equipment units,
and we introduce an improvement of the propagation algorithm for this
constraint. We then introduce a search strategy in which we sequentially solve
the sub-problems (packing and sequencing). Experiments conducted on real and
random instances show the respective interest of our contributions.
