NASA work OMS issue with Shuttle Atlantis

by Chris Bergin

As seen with STS-121, NASA are examining and re-examining even the smallest issue with a Shuttle on orbit, and that’s proving to be the case with Atlantis on STS-115.

Information acquired by this site show NASA is working 15 issues, including “areas of interest” on both port and starboard OMS (Orbital Manoeuvring System) engines.

**L2 STS-115 Coverage: ALL related handbooks, from Final Flight Plan to Robotics to EVA Presentations (600mb of 115 presentations downloadable) NOW INCLUDING:  STS-115 Rendezvous Handbook**.

**STS-115: LIVE COUNTDOWN AND LAUNCH Update Page** – **Flight Day 2**  **Flight Day 3 – Live**

Key Points/Newsflashes: Stunning RPM (RBAR) complete. Heading to docking.

Refer to live update thread for up to the second updates.

The following information has been collated from the vast amount of documentation, images and source updates on L2.

NASA engineers and technicians are comparing past flight data on the port OMS fuel tank skin temperatures, given data from Atlantis is showing hers is running ‘warm on the System B heater.’

On the starboard OMS pod, ‘suspect damage’ has the potential to be flagged for the focused inspection group, after initial sweeps on orbit show one of the tiles on the pod ‘has a red/pink contamination on tile….suspect the possibility of hydraulic fluid.’

Also being evaluated is Speed Brake driver channel 3, which was noted to be erratic.

‘Speedbrake Driver Channel 3 (ASA 3) indicates erratic behaviour suggesting an open circuit condition somewhere between FA MDM 3 and the Speedbrake PDU servo valve coil during Ascent, including post-APU shutdown,’ noted the information.

‘Behaviour of secondary delta pressures confirms that telemetry indicates a real condition. Erratic output did not persist long enough to cause automatic deselection of channel by ASA RM.’

However, the issue is tagged as having no mission impact, with the system being two fault tolerant. The issue is likely to have been an open circuit in wiring between FA MDM 3 and ASA 3 or ASA 3 and Speedbrake PDU, or related internally to the ASA.

Also a candidate for the focused inspection team are Wing Leading Edge impacts on panels 6 and 7, classed as an ‘anomaly,’ tagged as ‘Strong readings on lower sensors.’

A few other notes of interest include imagery that shows a debris impact – which splits into two as it hits Atlantis – although it occurred late into the ascent, thus is likely to be no concern as far as potential damage to the orbiter.

Made infamous by Steve Robinson’s space walk – and removal of on STS-114 – a protruding gap filler has been spotted sticking out on port wing, and is currently being measured.

So far, this mission has been going to plan, with Flight Day 2’s overview noting that all scheduled activities have been completed, with all Ascent Imagery data now downlinked. Flight Day 2 timeline proceeding nominally and ahead of schedule and Cryo Consumables currently support two extension days if needed.

Areas of interest in the led up to the launch of Atlantis are also proving to have no impact on the mission, with Fuel Cell 1 AC Phase A not affecting the smooth running of Fuel Cell 1 pumps, which continue to be fine on the remaining two phases. Plus, four N2 flow sensors, which were identified as all failed pre-flight, are all working as they should on orbit.

One lesser known issue on launch day was the emergency landing of an F-22 fighter jet, which had to utilise the arresting barrier at Edwards Air Force Base in California.

An F-22 Raptor pilot who frequents’s forum confirmed that the runway – used as a landing strip for the Shuttle at times when the Kennedy Space Center is not available, has now been cleared.

Tomorrow’s activities include one of the highlights of a mission for Shuttle fans, as Atlantis makes her debut RBAR pitch manoeuvre, allowing crew members on the International Space Station to take photography of her belly. That is schedule to occur at 04:31 Central Time, before docking with the International Space Station 75 minutes later.

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