SRE-FA is an active participant in payload studies. Instruments are in fact at the very core of science missions, often impacting heavily on the complete flight segment definition. Payload studies are conducted by ESA before the actual start of the project life, in order to assess its viability from a scientific, engineering and cost point of view.

Key activities in this area are:

• Contribution to the payload definition for future ESA Science missions
• Contribution to engineering trade-offs in view of maximising the scientific return for a given mission budget
• Identification of technological drivers and needs to be addressed in the development of future instruments
• Assessment of management and programmatic aspects

Layout of SAFARI (from the Instrument Design Activity study). Credit: ESA

As part of the Cosmic Vision 2015-2025 study activities, SRE-FA conducted (in June 2008) a dedicated Instrument Design Activity (IDA) on SAFARI (SPICA FAR IR Instrument), in the form of a short CDF study. The study provided the opportunity to better identify the instrument design drivers and the related technology development needs.

Based on the new scheme adopted for Cosmic Vision 2015-2025, SRE-FA is involved in the instrument studies conducted by the instrument consortia, helping to define the study objectives, monitoring the progress by the consortia and maintaining the link to the ongoing system level studies. These instrument assessment studies are to be completed at the same time as the ESA system level studies, thus providing a comprehensive picture at the time of the first Cosmic Vision 2015-2025 down-selection, planned for the end of 2009. The work done during the preliminary instrument assessment studies will be used as a basis for the release of the official Announcement of Opportunity (AO) for the payload provision.

Payload reviews

SRE-FA supported a number of payload reviews on ESA science projects. Such payload reviews monitor the development of the instruments in the member states and represent milestones at both payload and mission level. The actual review organisation depends on the specific characteristics and needs of each project. Organization and conduct of reviews are important in the context of space projects and they follow well defined standards such as ECSS-M-30-01A. Examples of typical instrument reviews, usually distributed with a yearly frequency, are as follows:

• Instrument Requirements Review, IRR, (when the project is in definition phase and aiming to verify the correspondence between science goals and instrument requirements, equivalent to the System Requirements Review conducted at mission level)
• Instrument Preliminary Design Review, IPDR, (following the IRR and aiming to verify the availability of an adequate preliminary design, equivalent to the Preliminary Design Review conducted at mission level)
• Instrument Critical Design Review (following the IPDR and verifying the availability of an adequate detailed design, thus approving the start of actual manufacturing activities, equivalent to the CDR conducted at mission level)
• Intermediate Hardware Review (aiming to verify the progress achieved during the development phase and the capability to meet all qualification requirements)
• Instrument Test Readiness Review (with the goal of verifying the readiness of the instruments to begin their final testing and qualification completion)
• Instrument Flight Acceptance Review (verification of end-to-end functionality and instrument performance, verification of correspondence to the initial science requirements, completion of qualification and formal acceptance of the unit for integration on the spacecraft).

Herschel SPIRE instrument. Credit:SPIRE Consortium

Over the past few years, SRE-FA has supported several Herschel and Planck instrument reviews, such as the Instrument Baseline Design Review (equivalent to the IPDR) of Planck/HFI (High Frequency Instrument), Planck/LFI (Low Frequency Instrument), Herschel/SPIRE, Herschel/PACS and Herschel/HIFI.

Artist's impression of the INTEGRAL spacecraft. Credit: ESA

In addition, SRE-FA has supported several reviews of SMART-1 and the IFAR of INTEGRAL. Each review requires the evaluation of a large number of documents and reports, in order to assess the work done by the instrument teams. Initial comments and questions are raised by the review board on the basis of the documentation and subsequently answered by the instrument team. A number of presentations from the instrument teams close the review process, with the preparation of a final review board report, containing all required recommendations.