Towards File-Based Operations for ESA Missions

Pecchioli, Mauro; Montagnon, Elsa; Calzolari, Gian Paolo; Flentge, Felix; Kowalczyk, Arkadiusz

doi:10.2514/6.2010-2190

Cited by 3 publications

(3 citation statements)

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“…With the adoption by the Euclid mission of the File Based Operations concept (Ref. [6]) based on CFDP ESA is taking a substantial step further in the use of file transfer to simplify onboard data management and operations, building on the experience gained on previous as well as current missions (Rosetta, Mars Express, Venus Express and Gaia). The move to file based operations involves not only changes to the ground segment but also, to realize its full potential, to the on-board system, and more importantly to the operations concept.…”

Section: Discussionmentioning

confidence: 99%

File based Operations, CFDP Assembly and Euclid

Haddow¹,

Dreihahn²,

Flentge³

et al. 2018

2018 SpaceOps Conference

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The first large scale European Space Agency (ESA) mission that will adopt a file bas ed approach to operations is Euclid, which is expected to be launched in 2021 and will explore dark energy and dark matter in order to understand the evolution of the Universe since the Big Bang and, in particular, its present accelerating expansion. It will have an operational orbit around Sun-Earth-Li beration-Point 2 and will generate about 100 GB of science data per day. To transfer these data to ground a high telemetry rate via K-band is required. The weather dependent quality of a K-band link requires a failure detecting downlink protocol with automatic retransmissions of corrupted or missing data segments. For this purpose, the CCSDS File Delivery Protocol (Ref.[1]) (CFDP) class 2 (reliable) has been selected. The operations concept for Euclid is that it will be an "offline" mission, i.e. there is a high level of on-board autonomy for routine operations and failure discovery, isolation and recovery. Scientific data and housekeeping telemetry (instruments and service module) will be recorded in the Mass Memory Unit (MMU) and daily ground contact will be of the order of 4 hours. Data will be downlinked as files from the MMU and telecommands uplinked in files to the Mission Timeline. Due to the guaranteed available bandwi dth between the Operational Control Centre (OCC) and the ground stations to be used for the normal operations phase of the mission (the ESA Deep Space Antennas at Malargüe, Argentina and Cebreros, Spain), it is not possible to rely on all the data being delivered to the OCC in real-time in a reliable way. In view of this, it has been necessary to make some modifications to the way in which the CFDP entity is deployed to cater for this. Essentially this requires the instantiation of a CFDP assembly at the ground station where the downlinked files are reconstituted, whilst CFDP control PDUs are routed to the control system at the OCC for uplink to the spacecraft. The routing of the CFDP PDUs for the uplink is largely a consequence of the use of the CLTU protocol for uplinking -CLTU only supports one command source. No changes to the underlying CFDP protocol are required.

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Section: Discussionmentioning

confidence: 99%

File based Operations, CFDP Assembly and Euclid

Haddow¹,

Dreihahn²,

Flentge³

et al. 2018

2018 SpaceOps Conference

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“…The Metop-SG Operations concept owes a lot to the file based operations concepts developed by ESA for recent interplanetary & deep space missions [2] . In particular, Onboard TC Sequences (OBTS) are implemented in the Airbus AS400 PUS Library and utilized extensively in the Metop-SG Operations concept, so are described here for background.…”

Section: File Based Operations -Onboard Tc Sequencesmentioning

confidence: 99%

Metop-SG Operations Concept: From Spacecraft Operations to Configuration of Onboard Autonomy

Dyer

Porta

Loretucci

et al. 2018

2018 SpaceOps Conference

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The EPS-SG mission will be supported by three pairs of satellites (Metop SG A and B) instead of three single satellites as for EPS. One of the main objectives in the definition of the operations concept is to avoid a corresponding increase in staffing costs compared to EPS and this paper focusses on aspects of the operations concept which will help achieve this goal. The resulting operations concept is facilitated largely by a more modern ECSS PUS based command and control specification and the use of Position based Scheduling of commands, but also relies heavily on file based operations and maintenance of the on-board operational context (including Application Software) in non-volatile memory and accurate modelling on ground. As such, it represents a fundamental shift away from Spacecraft Operations and towards Configuration of Onboard Autonomy.A novel scheme developed for efficiently maintaining the On-board Position Schedule is presented in this paper, along with the methods which allow the Onboard Position Scheduler to be used for types of commanding which are only partially linked to the Orbital Position and the 412 Orbit repeat cycle of Metop-SG. The result is that more autonomy is transferred onboard and the majority of the available ground station passes can be just used for passively monitoring the Metop-SG spacecraft without any active involvement from controllers.This paper also presents the rationale for storing Operational Context and Onboard Software updates in non-volatile memory and how this will allow simplification of anomaly recovery operations, further minimising the workload of the Flight Control Team as well as mission outages. In particular, the advantages of having two Application Software Images at the level of instruments is described here.

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“…The usefulness of files for operations and impact on the existing ground infrastructure has been under evaluation at ESA for several years, building on the experience made on the Rosetta, Mars Express, Venus Express family of missions 2,3 . What do we mean by "files"?…”

Section: A Files In Spacecraft Operationsmentioning

confidence: 99%

Truly File-Based Operations at Mars: Lessons Learned and Ideas for Future Missions

Lakey¹,

Blake²,

Sousa³

et al. 2014

SpaceOps 2014 Conference

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Since 2011 Mars Express has been flying a truly "file-based" concept for commanding the spacecraft and science operations, after a hardware anomaly forced a change from the previous "on-board schedule of commands" approach. As a consequence of the anomaly, new concepts had to be developed and applied to not just the technologies of file transfer and file management, which have received much attention over the years, but also to answer the questions: What are file-based operations? What goes in the files? How are they practically used both on ground and on board? ESA's first generation of deep space missions implement a packet-based large file transfer protocol to enable "files" to be transmitted from ground and guarantee the completeness on-board. However this is a transport-layer protocol and does not address the usage of the files operationally. Similar proposed standards (such as CCSDS File Delivery Protocol) also do not address the functionality of the files, and so by themselves do not necessarily lead to file-based operations. The Mars Express approach relies on seeing spacecraft operations not as a stream of commands, relayed from a mission planning system to the spacecraft via files, but as a collection of discrete activities, with one commanding file per activity. The contents of the file is the responsibility of the science planners, combining elementary sequences as per the rules defined by the spacecraft/payload operations engineers to construct self-contained, fail-safe sets of commands. For example, one science observation activity includes power, thermal, data link and instrument configuration changes that can be combined into one file (of telecommands, as an On-board Control Procedure, or a combination). Rather than individually scheduling the low-level commands, the activity file is simply executed at the correct time. If the observation needs to be modified or cancelled, the file is replaced or deleted. Spacecraft operations can conveniently be abstracted to the simpler paradigm: "which file to execute and when?" -the low-level constraints and resources checking having already been performed at mission planning level when that activity was planned. The ratio of commands-in-files to scheduled "execute" commands (the amount by which operations have been "compressed" by considering the higher-level "activity" file rather than low-level commands) is about 30:1 but is limited by available memory resources. Future missions with larger memories should achieve better than this, with fewer files containing more complex operations, resulting in even more abstracted operations overall. Mars Express has demonstrated a use case and implementation of file-based operations with regards to spacecraft commanding, but this is only half of the picture. The return of science data and housekeeping telemetry remains based on "packet stores". Packet stores are akin to looped SpaceOps Conferences magnetic tapes, in that the data is stored in the order in which it was written. For Mars Express this is not usually a pro...

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Towards File-Based Operations for ESA Missions

Cited by 3 publications

References 1 publication

File based Operations, CFDP Assembly and Euclid

File based Operations, CFDP Assembly and Euclid

Metop-SG Operations Concept: From Spacecraft Operations to Configuration of Onboard Autonomy

Truly File-Based Operations at Mars: Lessons Learned and Ideas for Future Missions

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