Activation of the Metop-A AHRPT Direct Readout Service
Information from EUMETSAT - 23 September 2008
Investigations into the failure of the Metop-A AHRPT side A have
concluded that the root cause was heavy ion radiation causing the failure of a component of the AHRPT Solid State Power Amplifier (SSPA).
The investigations additionally concluded that the redundant Metop-A AHRPT-B sub-system is likely to suffer a similar problem.
To minimise the risk of failure to the AHRPT-B unit whilst still offering the User community a service, EUMETSAT has decided to implement
a "partial" AHRPT service in those areas where the risk of damage from heavy ion radiation is reduced.
For southbound passes, AHRPT side B will be activated for all orbits over the North Atlantic and European area
starting at around 60°N. The AHRPT will then be switched-off before the spacecraft reaches the Southern Atlantic Anomaly region, at around 10°N.
The attached diagram indicates the zone of activation of the AHRPT. It is planned to have a trial period for 2 months, following which the
activation scenario will become operational.
In a separate development, EUMETSAT will implement a Fast Dump Extract service comprising the most recent part of the X-band global dump from
the ascending passes of the ASCAT, AMSU, MHS, HIRS, AVHRR, and IASI data streams, thus providing high-timeliness regional data for these
instruments. This data will be made available via the EUMETCast-Europe service.
The switch-on of the AHRPT service for the descending passes over Europe and North Atlantic region, will allow ASCAT, ATOVS, AVHRR and
IASI data to be available in due course from the EARS network of stations.
A retrofit of the failed SSPA component on-board the future Metop-B and Metop-C spacecraft is underway.
Due to known interference with HIRS instrument on-board Metop-A the LRPT service will not be activated.
Additionally, it is not planned to offer an LRPT service on the future Metop-B and Metop-C spacecraft.
Update - 24 September 2008
Further to the message of yesterday, EUMETSAT is pleased to announce the start of the Metop-A AHRPT trial service on Monday 29 September 2008.
EUMETSAT information about this is no longer available.