Tank safety – inspections called on the next External Tank set to fly

by Chris Bergin

Ahead of its scheduled mating with the twin Solid Rocket Boosters (SRBs) next week, engineers are carrying out detailed inspections on ET-120, the next tank to fly, with Discovery on STS-120.

The inspections will evaluate the condition of the tank’s LOX feedline brackets, following the foam liberation from Endeavour’s ET (ET-117) during ascent. Engineers will also look at reassessing elements of the tank for possible ice and foam loss minimization.

**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 **

Special STS-118 L2 Section now live, filled with documentation, processing memos, mission notes, videos, handbooks, checklists, and our very special live updates of actual live NASA mission notes direct from mission control, allowing you to follow the mission at the same time as NASA, along with real NASA/USA engineers helping update and explain status live. All totally unavailable anywhere else on the net.

**LIVE: FLIGHT DAY SPECIFIC COVERAGE** (Including links to all NASA Video – press conferences and mission milestones – for free).


At present, ET-120 is due for mating with the boosters inside the Vehicle Assembly Building (VAB) next Monday, although this is currently ‘under review,’ with an ET/SRB Mate Review scheduled for Friday. It’s due to launch with Discovery on a NET (No Earlier Than) launch date of October 23.

The tank has already had an eventful existence, being one of the four ETs that were shipped back to the Michoud Assembly Facility (MAF), following the loss of Columbia, which ultimately led to the requirement of Return To Flight (RTF) modifications.

Those modifications included a large number of foam reduction methods on various parts of the tank, the same reductions that were completed on Endeavour’s ET-117. Now, it appears, NASA are looking into potential techniques that will mitigate ice and foam liberation, without causing a notable delay to Discovery’s mission.

‘Following up on information on STS-118; issuing request for detailed inspection of ET-120 at LO2 feedline pour,’ noted the latest Stand-up/Integration report. ‘Also looking at reassessing trays for possible ice and foam loss minimization, and will come forward with this in a week or so.’

**Ride home through the fire, sparks and plasma of re-entry with Atlantis, Discovery and Endeavour. FOUR Stunning high quality 2hr, 355-400mb Camcorder and HUD videos – from payload bay closure to post landing – several more videos showing landing from 90,000 ft also available**

The same report backed up the continued push towards a nominal plan for Discovery’s scheduled launch date, with a rollover target update noting less than a month remaining in Discovery’s OPF (Orbiter Processing Facility) flow.

‘Have 23 days (as of Monday) until OPF rollout scheduled September 5; will try to get ahead of that date a bit,’ added the information, as Discovery picks up the processing pace, with her payload bay doors closing on Sunday.

The area of the liberation event for Endeavour during ascent was already undergoing a mitigation process, with the LOX (LO2) feedline brackets deep into the process of modifications which will kick in from ET-128 onwards.

This involves a titanium modification, which will remove yet more foam from the brackets, while reducing the chances of ice – also a debris risk – forming on the brackets. This modification is undergoing scheduled testing at the Marshall Space Flight Center (MSFC) this week.

‘Titanium yoke LO2 feedline support bracket redesign scheduled to come forward on ET-128, has series of test milestones this week at MSFC,’ noted the integration report. ‘Have an ice characterization test and the structural test planned this week.’

The modification will be put through its paces in a wind tunnel, which will test the foam configuration on the new brackets. It may also include a ‘hot gas’ test.

Back on orbit, and the crew of Endeavour and the International Space Station are in Flight Day 7, with the main element of the day being the successful transfer of the (External Stowage Platform) ESP-3 from Endeavour’s payload bay to the ISS’ P3 truss. The crew have also conducted interviews with the media and school children.

L2 members: All documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, updated live.


(Video section is FREE, but you need to sign up as a member of the forum to enter the video section of the site. We only use your e-mail to send you your password. It will not be used for spam etc.)

**NASASpaceflight.com Job Opportunities** 

Related Articles