If the stuck HGA ribs were to come free, could the HGA be immediately used?
There appears to be little hope that the ribs might come free, but, if they did, there would be a noticeable change in the spacecraft’s wobble angle. The spacecraft’s attitude control system detects a component of the wobble angle and sends it back to Earth. Analysts monitoring the spacecraft telemetry would see the change associated with rib release. Several steps would have to be completed before the High Gain Antenna could be used, however. First, the antenna motors would have to be commanded to unfurl the antenna. Second, the spacecraft would have to be turned to point the narrow beam of the HGA at the Earth. This would allow testing of the HGA’s performance. Third, this measured performance would have to be analyzed and subsequently incorporated into ground software to use in future sequence planning. Lastly, the already-built sequences would have to be updated to take advantage of the capability. Such a process would certainly take weeks to months to complete. Clearly a high prio
