The Use of the CCSDS File Delivery Protocol on Messenger

Abstract

MErcury, Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) is a NASA Discovery mission to study the planet Mercury. It will be launched in March 2004 and will include two flybys each of Venus and Mercury, followed by Mercury orbit insertion in April 2009 for a one-year science-gathering mission. Through both phases of the mission, MESSENGER will collect data from seven instruments on key characteristics of the planet to further understand Mercury and the formation of the inner solar system. As part of the system software developed by The Johns Hopkins University Applied Physics Laboratory (JHU/APL), MESSENGER will employ a standard developed by the Consultative Committee for Space Data Systems (CCSDS) called the CCSDS File Delivery Protocol (CFDP). CFDP is used to telemeter instrument and spacecraft housekeeping and science data stored on a spacecraft’s onboard file system to the ground system, and to transfer files from the ground to the spacecraft. CFDP was chosen for MESSENGER to allow for the reliable and direct transmission of files from the spacecraft to the ground. CFDP also complements the concept of a spacecraft file system, streamlining the gathering of data from instruments and the spacecraft. This paper describes how CFDP will be used on the MESSENGER mission. To provide a framework for discussion, an overview of CFDP is given followed by a description of the CFDP software. The flight software is a JHU/APL-designed implementation of CFDP, while the ground software was licensed from the Jet Propulsion Laboratory (JPL). The JPL deliverable, which will also be used on the upcoming Deep Impact mission, includes both the core CFDP functionality and a test harness for verifying operability between the flight and ground. An explanation of both architectures is shown along with a review of the integration of the JPL package into the ground software. Finally, an overview of the flight-to-ground file storage process is described to show how CFDP fits into the larger mission picture.