Reference Orbit Event Excerpt

As the ENVISAT Reference Orbit Event (ROE) File contains much more information than usually required for SCIAMACHY operations planning, SOST extracts the most relevant parts and generates a ROE Excerpt file. This is provided on the SOST web pages. In particular the file provides the relation between orbit numbers and UTC time.

The ROE Excerpt includes

• absolute orbit number (ABS)
• relative orbit number (REL)
• phase of mission (PHASE)
• cycle within phase (CYCLE)
• mean local solar time ascending node (MLST)
• geographic longitude at ANX (ANX_LONG)
• time of ascending node crossing (ANX) in UTC and additional time format (yyyy.ddd.hh.mm.ss.sss - note that ‘ddd‘ is the daynumber/year starting with ‘1‘ on January 1^st, 0h while all mission planning related times use daynumber ‘0‘ on January 1^st, 0h)
• time of start of first timeline in orbit (UTC_FTL) when first timeline is solar occultation timeline
• time of exit out of eclipse phase (EXIT)
• time of entry into eclipse phase (ENTRY)
• orbit duration (PERIOD) in sec
• repeat cycle (REP. CYCLE) in days
• South Atlantic Anomaly flag (SAA) for passage through the SAA in the descending (day) or ascending (ecl) part of the orbit

The filename of the ROE Excerpt specifies the start/stop orbits contained in the file. In the ROE Excerpt header, the original ENVISAT ROE filename is given.