What are operators and constructors doing ?

Over the last ten years, one third of operators of satellites in geostationary orbit have been following the recommendations correctly, one third have been ignoring them and the remaining third have been observing them only partially, in that they have not always raised the orbit of end-of-life spacecraft sufficiently. But for the last three or four years, more have been joining the first third, a sign that the message is spreading around the world.

Arianespace

The Director of Arianespace at Kourou admits that, when negotiating with a satellite customer, although Arianespace stresses the good practice rules the contract itself currently includes no reference to debris. As a launch operator, Arianespace at the moment is only subject to a single constraint: one piece of debris per satellite. For double launches this means the upper stage (including the adaptor for the lower satellite) and the SYLDA double launch system for Ariane 5 (including the adaptor for the upper satellite). In addition, if the latter element is destined to remain in orbit for more than 25 years, the launch operator is responsible for placing it in a stable orbit above the protected region. Though Arianespace’s contracts go no further than injection for the time being, it is possible that future clauses of the Space Act may extend its responsibility beyond this point, to cover the fall-back of stages after injection.

Thales Alenia Space

Technical progress prompted by the debris issue

The first generation of weather satellites were stationed using solid-fuel motors that produced quantities of debris. Henceforth, the propulsion system is an integral part of the satellite. The second generation was obliged to include covers to protect the highly sensitive optics. This raised the problem of jettisoning these very large items (an oval of about 100 x 50 cm with a diameter of 160 cm) before reaching geostationary orbit. The orbit acquisition procedure was adapted, with the telemetry data received proving that operational integrity was achieved. For the third generation currently being developed, the difficulty is greater because satellites, for whatever mission, are no longer allowed to create any debris at all. As a satellite builder, Thales Alenia Space now has to find a way of leaving the covers attached to the satellite after they open. This is a considerable challenge for constructors who need to find a system that both opens them and leaves them blocked in place. This solution has been successfully applied to Herschel, whose cover opens and remains blocked in place without either obstructing the field of view of the optics or creating stray light by reflection, which would compromise the mission. As with any other spacecraft, a science satellite is expected to include its de-orbiting needs in its fuel budget.

Who is responsible when problems arise?

As a launch country, France delegates the responsibility for launch hazards to CNES, so that in the event of fall-back during launch it is CNES, and particularly its Range Safety Department, that would take charge of damage limitation or recovery operations. This will be reinforced by the Space Act.

As launch operator, Arianespace is responsible for damage caused either on the ground or in airspace, with its liability being guaranteed by the state beyond a mutually-agreed sum.