“Data Format Discrepancy” Delays Cygnus Approach to Station

Credit : Orbital Sciences

Orbital Sciences posted the following update regarding the COTS D1 mission on Sunday; “Following the discovery of a data format discrepancy between an on-board International Space Station (ISS) navigation system and a similar system on Cygnus at around 1:30 a.m. this morning, today’s rendezvous with the station was postponed. At this time, NASA and Orbital are developing a detailed plan for a second rendezvous attempt early Tuesday morning. A software update has been developed and will be tested on a ground-based simulator during the day on Sunday. Upload to Cygnus and in-orbit testing of the software “patch” is planned for Sunday night and into Monday morning.

Once this has been accomplished and verified, the current plan is for Cygnus to begin a second rendezvous approach late Monday night, with final approach to the ISS and grapple taking place early Tuesday morning. The Cygnus spacecraft remains healthy, with all major subsystems operating as expected.”

As noted in the pre-launch press conference, according to OSC, with solar panels deployed, Cygnus has a loitering capability which  could theoretically be extended as far out as a month, presumably giving the company ample time to address the problem if the first fix does not do the job.