Accounting for specific DR restrictions¶
For some satellites and some instruments direct readout is not available constantly. This is the case for instance for MODIS onboard the EOS Terra and Aqua satellites.
Aqua and Terra dumps¶
During the time when the EOS satellites make their global dump there is no Direct Broadcast available for Direct Readout users. In order to disregard the scheduling of local reception of data which will not be available due to these restrictions the NASA Direct Readout Lab publish Terra and Aqua Direct Broadcast Downlink Scheduling Information regularly. The Pytroll-schedule take these reports into account when deriving the local schedule.
Due to a broken A-side of the Metop-A HRPT downlink module only the B-side is operable on the Metop-A spacecraft. The A-side failure was due to a malfunctioning transistor that proved to be sensitive to cosmic radiation. The same transistor is available on the B-side and therefore EUMETSAT has implemented a restricted operation of the B-side HRPT downlink module. This means no HRPT direct broadcast is available during parts of the Metop-A orbit (e.g. over the North Pole and around the South Atlantic Anamoly).
For direct readout users EUMETSAT regularly (several times per day) publish an HRPT on/off schedule in XML format at the following URL:
This will be read by Pytroll-schedule in order to disregard Metop-A where there will be no Direct Readout available over the relavnt local reception station. NOT YET IMPLEMENTED!