scheduling feasibility checker

The Scheduling Feasibility Checker, or SFC, is a tool that is used to check whether and when a target is visible to CHEOPS. It is also used to assess the impact that interruptions due to passage through the South Atlantic Anomaly and Earth Occultation have on visibility of the target, together with the observing efficiency, or fraction of time within a period of visibility can be spent collecting photons from the target.

The tool is designed to run on your own computer, and as such is available as a virtual image that in turn runs on a virtual machine.

Instructions on how to install both the virtual machine and the latest version (July 2020) of the tool itself are given below, as are the latest guidelines for the use of the tool.

  • Installation guide (updated November 2022 to reflect changes in the guidelines on how to download the SFC image from ESA)
  • User guidelines (issued July 2020, remains applicable)
  • See points noted in "Important notes" below detailing updates relevant to AO-3

Due to restrictions in the way in which the ftp protocol can be used with the current generation of internet browsers, it is recommended to download the virtual image using a standalone FTP tool such as Filezilla (

Host =

username = cheops_fc

Note that the connection requires the non-secure ftp protocol to be used, the explicit sftp protocol will not work. As a result, you might see the message "insecure server, it does not support FTP over TLS", which you can ignore.

A password is also required to download the image. This can be found by clicking on this link. To be able to see the page, you will need to be logged on to the Cosmos site (sign in at the top right of this webpage) and a member of the Guest Observers Group (click on Registration to the Guest Observers Programme on the toolbar menu for details on how to register).


Important notes:

  • Difficulties have been experienced by users using the SFC with the UBUNTU OS. Details of how to address these are given on the FAQ page for the AO (Q5) which can be found at this link.
  • VirtualBox currently does not support the Apple M1 chipset. There is no remedy to this problem other than using different hardware.
  • To be able to view possible visits to the very end of the nominal mission, it is necessary to change the "Validity_Stop" date in the HTML files used by the SFC to specify details of observation requests to UTC=2023-09-25T00:00:00 (this is necessary for both time-critical and non-time critical observations).


Latest update: 15 November 2022