STS-122 Countdown: Tanking proves good ECO sensor system

by Chris Bergin

Tanking began at 5:21am local time) for STS-122, in the first real test of the modified LH2 Feed-through connector and ECO (Engine Cut Off) system. SIM tests showed the four LH2 ECO sensors go DRY on command, with good voltages – providing large amounts of confidence that the previous issue has been resolved.

The weather is currently unlikely to cooperate with this afternoon’s launch, with a 70 percent violation of acceptable conditions, though the countdown will continue in the hope of finding a gap in the weather.

**The most comprehensive collection of Shuttle, Ares, Orion and ISS related presentations and mission documentation, plus expansive daily processing documentation and updates are available to download on L2 **

STS-122 L2 Special NOW LIVE. **Click here for sample of L2 menu and content**

**STS-122 Special: 29 Flight Readiness Review (FRR) Presentations, Baselines and Mission Overviews. **Click here for FRR overview articles: Article 1Article 2** Payload Presentations and vast amounts of live, uploaded images and presentations, movies (several) – already 3100 megabytes strong**

**COMPLETE Section – over 1350mbs of presentations – on ECO/Feedthrough Connector issues and troubleshooting, graphical and data based – expansive.**

**LIVE updates on Atlantis STS-122 COUNTDOWN Latest**

STS-122 ECO related news content (all exclusives): *Scrub 1* – *MMT Debate* – *Scrub 2* – *Hale Memo* – *Forward Plan* – *Culprit Found* – *Tanking Test* – *Repair Options* – *MAF Plan**PRCB Debate* – *Plan Approved* – *Repair Schedule* – *Launch Date* – *New Issue* – *Hale Rallying Call* – *PRCB Launch Dates* – *New Connector Installed* – *Positive Test Results* – *Manifest Impacts* – *Optimism with forward plan* – *Flight Rationale* – *Repairs Finalizing* – *Root Cause Confirmed*

STS-122: Hose related news content (all exclusives): *Issue found/fleet to be checked (December)* – *Atlantis found to have problem* – *Managers discuss forward plan* – *Use of pole to aid retract* – *Successful Retraction*


UPDATES: (Wednesday morning):

ET-125 preparing for tanking – currently in chilldown. Tanking begins at 5:21am.
No issues are being worked on Atlantis at this time.

SIM Test shows LH2 ECO sensors to be in good shape, commanding to DRY sucessfully, with good voltages!

Orbiter Flow:

Processing at the pad has continued without any major issue, with only two ‘Cat II’ notes of interest – both expected to be closed out ahead of flight.

Tasks completed in the S0007 Launch Countdown flow include: SSME (Space Shuttle Main Engine) final preparations and TSM (Tail Service Mast) securing completed. COMM switchlist and activation completed.

Dock seal deflation has been completed. Fuel cell activation was completed. Air to GN2 changeover completed. Final load preparations completed.

As with every pre-launch flow, a number of issues have been worked. None appear to be a constraint to launch, receiving either a waiver, or a post launch work requirement.

‘During review of PLB (Payload Bay) closeout photos, a decal used as a visual cue for proper alignment of the RMS (Remote Manipulator System) elbow camera was visible,’ noted processing information on Thursday morning.

‘The decal should be hidden when properly aligned. Mission specific clearance analysis was performed and determined that a positive clearance would be maintained between the radiator.

‘During a walkdown of the MLP (Mobile Launch Platform), corrosion was found on the LOX fill pipe support #6. Corrosion was removed from the pipe support lower saddle. Rationale was written and approved and will be further addressed post launch.

‘Secondary GN2 Accumulator Pressure is not trending with primary indication. Preliminary indications appear issue to be instrumentation failure. Alternate monitoring methods may be used should the primary method fail – and deferred constraint until next flow.

‘Suspect Frayed/protruded gap fillers forward of RH ET (Right Hand External Tank) door. TPS (Thermal Protection System) Engineering determined discrepancy to be minor stitching threads from gap fillers. Processed for acceptance as is and closed.’

(Updates on the live threads, key points published into this article).

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