Phase-2 of this programme covered the evolution of the TTC product taking into account findings from the first qualification campaign and aimed to accommodate market requirements that were not previously addressed. The changes implemented in Phase-2, which required a full qualification campaign were as follows:
Ultimately, the main objective of the programme was to qualify the transceiver and antenna filter system for use on an ESA programme. and provide a baseline product that can be utilized on other missions requiring an S-band TT&C / downlink transceiver.
Given that the initial design of the equipment was based on COTS components and the goal was to satisfy the requirements of an ESA science mission, the project had to overcome numerous challenges during development.
The implemented updates included a complete re-evaluation of the equipment design and identification of areas that needed to be further validated by additional testing or design modifications. Two major areas that required significant effort were the cost driven component selection and the radiation tolerance of the equipment.
The updated qualification campaign involved both TiD testing and SEE/SEU testing at sub-system level, aiming to characterize the equipment behaviour/tolerance under higher radiation levels.
In line with the original goals, the project has achieved its objectives and now offers the following benefits:
The Honeywell S-band TT&C transceiver is a single integrated module capable of both receiving uplink telecommands from a ground station for satellite control and receiving telemetry data from the satellite OBC for modulation and transmission back to the ground station.
The transceiver is based on a Software Defined Radio architecture and is configurable into a variety of operational states via OBC originated MODE commands. It can be programmed with a variety of different receive and transmit modulation schemes:
It provides health and status data to the OBC via a housekeeping (HK) interface. The MODE and HK interfaces work on an asynchronous interface over RS-422 while tele-command and telemetry are synchronous over RS-422.
The band pass antenna filter is configured as two independent band pass filters (transmit and receive) in one housing for separate TX / RX antennas. Alternately a diplexer variant can be supplied for TRX antenna systems. The transmit filter has been designed to ensure that the TT&C will comply with ECSS regulations concerning RF emissions and that the transmitter section of the transceiver will not interfere with its and other on-board receivers.
The transceiver is divided into three modules:
The development was structured into four main areas of activity:
The qualification schedule was aligned to the ESA CHEOPS mission requirements with an expectation that this would be expanded to further ESA missions after qualification.
The main aims of the 2nd phase of the CETB programme were to increase the functionality of the transceiver, characterise its performance and address the need for a high quality, lower cost TT&C unit. The acceptance of the equipment by an ESA mission (CHEOPS) was a secondary aim that proved the suitability of the equipment for an ESA science mission. ESA’s input to this programme was invaluable and helped Honeywell’s technical experts complete a successful qualification campaign.