ESA Memo to Experimenters Regarding Rosetta Spacecraft Defueling

Subject: Rosetta Launch Campaign

Dear Experimenters

To our great satisfaction, the activities in CSG / KOUROU, have resumed
last week with the defuelling of one of the combustible tanks (MMH).
This can be seen as a major achievement for the Project.

Some time ago, a major concern had been raised with respect to
the off loading of the oxidiser(NTO) from the PFM spacecraft with the need
for a better risk evaluation,as it appears that after off loading
a residual nitric oxide acid remains which could
adversely effect the stress corrosion of the Titanium tank.
This was the reason for which the tank was replaced on the GALILEO
spacecraft during storage and which promted Astrium to advise ESA
not to off load the oxidiser but only the MMH and keep the system
pressurised.
After several round of negociations , ESA came to the conclusion,in agreement
with the CSG safety authority, that to off load the oxidiser tank would be
too risky
and decided to off load the MMH only, an activity completed today.

As you can imagine such S/C configuration has implications,imposing some
precautions to be taken for all planned activities to be carried out in the
Hazardous Facility called S3 and allocated to Rosetta. It also requires
that all tasks are documented and reviewed by safety personnel prior to
their approval which by definition is a time consuming process.

Concerning the System Functional tests activities planned during the month
of August/September (see ID 61 to 64) , they will be organised as follows:

– SFT4/FAT3 will be conducted from CSG , ESOC being in a listening mode

– SVT3will be conducted from ESOC, with CSG in a listening mode. This scheme is the same” as run” during the first campaign and you could organise your support in a similar way?

The Launch campaign will formaly start on the 24th of October, the spacecraft
being fully equipped with its Flight items. The activities will mainly focus
on the
verification of mechanical elements and the S/C close out in its final flight
configuration.
Begin 04 will be dedicated to the refuelling activities and the preparation
of the S/C
for transport to the BAF in order to start the combined operations with the
Launcher,
by the 10 th of February.
The first opportunity for Launch is fixed to the 26 of February 04

In this frame of activities, I ask your full cooperation and understanding,
bearing in mind
that we have a reduced team and that there are always lurking risks in any
of these phases.

Looking forward to seeing you ,

Best Regards,

Claude Berner

Payload & Operations Manager

Rosetta Project.