Endeavour STS-127 Pad Flow Latest:

Engineers have ably guided Endeavour through her pre-launch processing milestones, despite time constraints relating to turning the vehicle around after the successful tanking test at the start of the month.

No technical issues are being worked on the vehicle, with the only additional work relating to cosmetic damage observed on the left hand Solid Rocket Booster (SRB) and the removal of cracked foam from External Tank (ET-131′s) LO2 Feedline.

“Orbiter: OV-105 / ET-131 / BI-138 / RSRM-106 (Pad-A): S0071, OMS/RCS/MPS Orbital Maneuvering System/Reaction Control/Main Propulsion System) hyper pressurization for flight is complete less post ops,” noted processing information on L2.

“ET-131-TS-0019, the repair of cracked foam on the ET LO2 feedline began on Wednesday. Left-hand SRB paint defect repair: Sanding and sampling of the area is complete.

“Samples were taken to the lab to verify the presence of rust. Eddy current testing revealed no anomalies. Primer and top coat application are complete.”

Nominal procedures completed in the recent flow included the programming of the WLE IDS (Wing Leading Edge Impact Detection System) units, which have a primary role of “feeling” any debris impacts on the orbiter’s RCC (Reinforced Carbon Carbon) panels during ascent.

“Wing Leading Edge flight programming was successfully completed on all units. Range safety system re-programming and battery change out is complete. The flight doors have been installed.

“LOX storage tank sampling was completed (earlier in the week). APU/HPU (Auxiliary Power Unit/Hydraulic Power Unit) cart GN2 sample is complete with nominal results. The GH2 battery recharge was rescheduled for late Wednesday.”

The STS-127/2J/A mission package includes the Japanese Experiment Module – Exposed Facility (JEM-EF) and the Japanese Experiment Logistics Module – Exposed Section (ELM-ES) as well as the Integrated Cargo Carrier – Vertical Light Deployable (ICC-VLD).

Atlantis/STS-129 Processing Latest:

Positive news has been reported on the results of mold impressions taken on Atlantis’ Window 5 pressure pane, which has found the damage – suffered when a work light knob was found to be embedded between the pane and the dashboard – is not serious enough to warrant the pane’s replacement.

Given the challenging aspect of replacing the pressure pane, Atlantis would have expected to endure a six month impact on her processing flow inside OPF-1 (Orbiter Processing Facility).

“The window was inspected after the knob was removed. The deepest defect is approximately 0.0003” depth, the reportable depth threshold is 0.0015” and above,” noted findings from the mold impressions taken on Monday night, and acquired by L2.

Thanks to the successful removal of the knob – via the pressurization of the crew cabin in tandem with the application of dry ice to shrink the knob – no additional damage was suffered to either the pressure pane or the surrounding hardware.

Had that removal procedure failed, more intrusive methods would have been employed, which in turn had the potential to increase the damage on the pane.

“Pictures show that it is unlikely metal from the knob is still trapped in the defect,” added the findings. “Whether the coating requires replacement will be discussed.”

The news means Atlantis remains on track for a launch No Earlier Than (NET) November 12, 2009, on a mission that will deliver the Express Logistics Carriers 1 & 2 (ELC-1 and ELC -2), along with SASA and MISSE (Materials on International Space Station Experiment) 7A and 7B, to the Space Station.

Nominal processing work has continued throughout the window evaluations, highlighted by troubleshooting on the radiator flow control valve – an issue noted during Atlantis’ STS-125 mission to service the Hubble Space Telescope, along with the removal and replacement of the S-Band right-hand lower antenna.

“Ammonia boiler flushing continues and should terminate late Wednesday. Freon coolant loop 1&2 functional checks were completed on Tuesday. Engineering is evaluating data results,” noted processing information on L2.

“S-band thermography was completed Tuesday. S-band antenna removal picked up Tuesday night. Re-installation is planned for Thursday.”

Discovery/STS-128 Processing Latest:

Discovery is preparing to rollover to the Vehicle Assembly Building (VAB) on July 14, ahead of her August STS-128 logistics mission – carrying the MPLM (Multi-Purpose Logistics Module) Leonardo primary payload to the ISS.

“Structural leak checks will be completed this week,” noted the Shuttle Standup/Integration report on L2, citing United Space Alliance (USA) Ground Operations. “Orbiter final power down occurred Tuesday at 1300 EDT.

“Weight and CG (Center of Gravity) work done on Wednesday, and the vehicle will transfer to the OTS (Orbiter Transporter System) on Thursday, July 9. The vehicle should be ready to roll to the VAB on July 14.”

Ahead of transferring the veteran orbiter on to her taxi ride to the VAB, engineers worked through the final pressurization of the vehicle’s landing gear. All went to plan, bar an issue with a transducer associated with the reading of the tire pressures.

“Final tire pressure for flight, Nose Landing Gear was completed last night. Main Landing Gear will be completed late Wednesday.

“Pressure transducer milli-volt reading does not correlate to tire pressure. Troubleshooting plan is to take the pressure panel to the highest acceptable pressure band for the tires and then check the transducer milli-volt reading.

“If bad then the plan is to take the pressure panel to the lowest acceptable pressure band for the tires and if the transducer milli-volt reading is still bad then we’ll reconfigure with a different pressure panel.”

The actual mating of Discovery to the OTS will occur during first shift on Thursday, with Call to Stations (CTS) at 6am local time.

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

No related posts.

Atlantis’ Window Latest:

Engineers had an array of options to remove the knob, with a plan to use the least intrusive – and subsequently less damaging to the window pane – methods, in the hope of avoiding a requirement to replace the pressure pane, which would result in a standdown of the orbiter for up to six months.

Click here to read the article first revealing the news last week:
http://www.nasaspaceflight.com/2009/06/window-damage-on-atlantis-threatens-six-month-delay-to-sts-129/
UPDATE, DAMAGE CLEARED:
http://www.nasaspaceflight.com/2009/07/endeavour-into-countdown-atlantis-window-damage-cleared/

Late on Monday, a technician, an engineer, and a SpaceCraft Operator (SCO) entered Atlantis, ahead of a slight pressurization of the orbiter.

It was hoped that the slight expansion of the flight deck under pressurization will help free the knob. However, Atlantis can only be pressurized to a maximum of 3 psid, compared to the 14.7 psid on orbit. Dry ice was again used to try and shrink the knob to aid it’s removal, although an opening attempt using this method failed.

“Plans for Window 5 have been developed, to remove the knob that is wedged between the panes. The crew module will be pressurized during second-shift (ends midnight) on Monday, in an attempt to dislodge the knob,” noted processing information on L2.

“Preps to configure the crew module for pressurization are expected to be completed 1st shift today with testing to begin on 2nd shift.

The successful removal of the knob late on Monday night has been confirmed, although several opening attempts failed to liberate it.

“The pressurization of the vehicle and cooling did not remove the knob. The vehicle was pressurized 3.7 psi above ambient to 17.87 psi. The knob was cooled with slugs to -9 deg F. Other options will be discussed to remove the knob,” noted an opening log report last night on L2, prior to success being noted at the end of the second shift.

“The go ahead was given to use hand pressure to manipulate it loose. The knob is out of the ship. First shift needs to add disposition to take molds of the window.”

“Crew module pressurization testing was successfully completed last night. The knob that had been wedged between the pressure plate and dash structure was liberated at 2247EDT,” confirmed Tuesday morning processing information on L2. ”Window will be inspected for damage using borescope.”

Evaluations into whether Atlantis will require the replacement of the pressure pane are now taking place, with proposals of new inspection methods – and a special inspection tool – under development this week.

Small areas of damage have already been observed where the edges of the knob are embedded into the pane, although engineers are hoping the borescope images are showing mainly cosmetic damage, as opposed to a breach of the pane’s safety criteria.

“Discussions were held with OPO on how best to remove the knob from Window 5. Borescope inspection reveals that the knob is wedged between the panes and may have already done damage,” the Orbiter Project Office (OPO) noted ahead of rhe removal on the Shuttle Standup/Integration report (L2).

“After the knob is removed, in-depth inspection must be performed to determine the extent of damage to the window. If the window must be R&R’d, it will result in a very long downtime (worst case estimates range as far as six months).

“Multiple techniques are being investigated on how best to remove the knob. As the pressure in the crew module decreased from a high of 14.7 psi, the item became stuck. It is hoped that this can be reversed by pressurizing the cabin again. The team will do everything possible to safely remove the knob and salvage the window.”

It has been confirmed by shuttle management that a spare pressure pane for window 5 is in stock, while long lead items such as associated seals are being looked into.

Manifest Impact In Event Of Replacement:

Should evaluations call for the replacement of the pane, Atlantis is likely to be removed from STS-129 duty due to the length of her standdown. Contingency planning is already taking place into handing the flight to Discovery.

Although a stretching of the manifest is unavoidable, the main area of discussion relates to Discovery breaching her eight flight OMDP (Orbiter Maintenance Down Period) limit.

This limit is based on a timeline that was extended in 2007 to allow the fleet to fly out the remaining missions on the manifest, without the one year standdown for their scheduled OMMs (Orbiter Major Modification) periods.

Back in mid-2007, engineers devised a priority list of work that was required on Atlantis, creating ‘mini-OMDP’ processing which could be conducted inside the OPF during regular post and pre-flight flows.

Atlantis originally had no choice but to retire in 2008, given she was due for her overhaul in that year, which would have been deemed pointless as she would be returning to flight status near the end of the shuttle program. The original plan back in 2007 was to retire Atlantis into a spare parts donor to her sisters after arriving back from STS-125.

However, engineers designed the ‘3 year / 8 Flight OMRSD (Operations Maintenance Requirements Specifications Document) Review’, which created the option to extend orbiter’s flight status in-between OMDPs to eight flights and five and a half years – instead of the previous three years. Only Endeavour was able to fly until 2010 under the previous definitions.

Following PRCB (Program Requirements Control Board) approval, the FAWG (Flight Assignment Working Group) handed two “extra” missions to Atlantis, thus reducing the burden on Endeavour and Discovery.

The Space Shuttle Program (SSP) also successfully argued the importance of flying out the schedule with three orbiters, so as to ensure an on time transition of shuttle resources to Constellation, ultimately resulting in NASA approval of the plan.

However, the incident with Atlantis has now switched focus back to Discovery, with the addition of STS-129 – should Atlantis’ pressure pane require replacement – breaching those refined OMRSD rules.

“If a ninth flight is required for OV-103 (Discovery) to complete the manifest, we run into issues with the mandatory OMM scheduled after its eighth flight,” added the Orbiter Project, via the Standup (L2).

“The current manifest does not afford room for an OMM. Initial work is in progress to determine what items can be waived or pushed off to a later date and what work will have to be slotted into the flows as time allows.

“The OMDP requirements (roughly 830) are being scrutinized in case a ninth flight is required on OV-103. Good rationale exists for about 380 of these requirements and the remaining 450 are being investigated. In the past, the OMM has been extended past eight flights, based on appropriate flight rationale. This is being researched.”

Longeron Cart Accident:

Evaluations are taking place on several items of payload equipment that fell of a truck that was transporting the hardware to Atlantis’ OPF last week. The cart contained several structural beams – known as longerons – that are installed between bays for supporting payloads.

“During transport of the longerons for OV-104 (Atlantis), the work cart holding the equipment fell off of the truck. The Accident Investigation Team reported immediately to the scene. Payload Engineering also responded to monitor lifting and securing the cart,” noted processing information on L2 late last week.

“The equipment was moved back to the Flight Kit Facility processing area to be secured. Evaluation and unpackaging of the container has begun. The hardware consisted of three longeron latch assembly build-ups (Bay 6 Starboard, Bay 10 Starboard, and Bay 10 Port). These three assemblies consist of roughly 150 unique piece-parts.”

It is hoped most of the hardware is still acceptable for flight, and subsequently will not become a schedule impact to STS-129 – regardless of the evaluations into Atlantis’ Window 5 pressure pane.

“Initial evaluation to the manifest impact shows two of three longerons available (missing the Bay 10 Starboard), and one of three latches are available (missing the Bay 6 Starboard and Bay 10 Port),” added the report. “The Bay 10 latch is a standard weight latch, but there is a middleweight latch available.

“The Bay 6 latch is a lightweight item, but there is a middleweight latch available. This issue will be worked with the Engineering Community to see if these are acceptable. Worst case outcome at this time is for the Bay 10 Starboard longeron.

“The investigation into the root cause of this accident is ongoing, and a safety stand-down of all three shifts of transportation drivers was held. All packaging and transportation procedures were revisited before they were released to do more work.”

The incident is understood to have occurred when the truck turned a corner just outside the OPF buildings. The cart wheel’s locking system is believed to have failed.

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

No related posts.

STS-129/Atlantis Processing Latest:

Recently returned to the home comforts of her Orbiter Processing Facility (OPF 1) after the successful STS-125 mission, Atlantis is being processed for the November 12 NET (No Earlier Than) launch date for STS-129.

The final mission of 2009 will see Atlantis deliver the Express Logistics Carriers 1 & 2 (ELC-1 and ELC -2), along with SASA and MISSE (Materials on International Space Station Experiment) 7A and 7B, to the Space Station.

Processing is proceeding to plan, with functional testing and post flight deservicing and troubleshooting currently taking place.

“The Aft Propulsion System (APS) pod functional checkout continues through next week,” noted Wednesday processing information on L2.

“Waste Management System post flight servicing is complete less post ops. The Star Tracker Lightshade inspection was rescheduled from yesterday to today. S-band trouble shooting (IPR-0014) begins today.”

Engineers are also working one issue noted with the orbiter cooling system, specifically the Freon Coolant Loop (FCL) 1 Radiator Flow Control Assembly (RFCA), which “failed to get into radiator flow on orbit.” However, engineers have been unable to recreate the issue inside the OPF.

“Functional testing resulted in nominal operations,” added the processing update. “The RFCA was cycled eight times without an anomaly. Data will be reviewed with JSC (Johnson Space Center) and the vendor.”

As per normal in an orbiter’s flow, all of the vehicle’s windows are being inspected for potential damage to the thermal pane – the outward facing pane – due to the usual occurrence of small MMOD impacts. These panes can be replaced reasonably easily.

“Window 1 Loctite application began yesterday and is scheduled to complete today,” added Wednesday’s update, following last week’s installation of a replacement thermal pane on that window.

However, it was during those inspections where potential damage to the inward facing pressure pane was observed on Window 5.

Window 5 Evaluations:

“Quick shoe mount knob from a crew work lamp was found wedged between pressure pane 5 and dashboard panel. Knob must be removed to evaluate pane condition before flight,” noted one of two expansive presentations, dated June 24, and created for high level managerial overviews – both presentations are available on L2.

Several attempts have already been made to remove the knob by applying dry ice in the hope the knob would shrink, thus allowing for it’s removal without causing additional damage to the pane. However, those attempts have been unsuccessful.

“The Shuttle expands when on orbit. While on orbit, a knob got stuck between the window and the frame on Window 5 (Pilot window),” added another memo on Wednesday (L2). “They have tried a number of tricks to remove it with no joy so far.

“If they have to remove the window, there is a schedule hit. Initial estimates are long, but initial estimates always are long before they sharpen their pencils.”

Those estimates speak of up to and over six months being added to the processing flow of Atlantis, which would have a major impact to the overall manifest that already has a full five flight schedule in 2010.

Even if Atlantis was retired as a result of a half year-plus processing hit – one absolute worst case scenario noted by one engineer on Wednesday – two orbiters could complete the manifest. However, due to LON (Launch On Need) requirements, a manifest stretch deep into 2011 would be the fallout.

Such discussions will not take place unless unacceptable damage is found on the pane after the knob is finally removed.

Inspections of knob have been carried out via borescope inspections. Photography shows the mounting plate appears to be dug into close-out panel. Further inspections will be required ahead of potential plans to remove the knob without causing additional damage.

Unique engineering plans would have to be drawn up in the event of unacceptable damage being found on the window, given a pressure pane has never been replaced at the Kennedy Space Center (KSC) over the history of the shuttle program, and ferrying Atlantis to Palmdale is obviously no longer an option – after the Orbiter Major Modification (OMM) facility at Plant 42 was shut down over six years ago.

The bottom line is Atlantis would not be allowed to fly – in the event of the pane breaching unacceptable damage criteria – due to the risk of the window failing during her next mission, which would result in a LOV/C (Loss of Vehicle and Crew) event.

“Knob wedged between pressure W5 and dashboard could have caused damage to pane and its currently loading the pane at two points. Removal of knob is required to evaluate condition of pane for flight,” added one presentation.

“‘Fly as is’ is not an option, unknown damage and loads to the glass could result in failure during the flight, with no redundancy; dynamic failure could result in redundant pane failure.

“Induced damage of the knob being wedged between the glass and the dashboard closeout panel structure, or from removal of the knob could result in unacceptable damage.

“Consequences of unacceptable damage to the glass pane: Replacing the pressure pane would result in a significant impact to ground schedule (potential 6+ month impact). Requires de-configuring dashboard structure and instrumentation to remove window assembly for refurbishment. Windshield pressure pane removal has never been performed at KSC.

“Knob removal must be performed carefully; exhausting all risk free options first, then attempting more intrusive (higher risk) options, if others fail.”

Damage to the pane is confirmed in the main overview presentation. Although the full extent won’t be known until the knob has been removed.

“Photos show evidence of existing damage to the pane. Cannot be assessed until knob removal. Glass is an aluminosilicate tempered pane (t=0.65). Tempered layer 21 percent of thickness or around 0.13 inch. Tempered glass has a built in residual stress, tempered layer penetration will result in failure.”

As far as unacceptable window damage criteria, ding depth greater than 0.0015” and/or coating scratches with a width greater or equal to 0.050” are listed, along with “no acceptable criteria for bruises or chatter checks.”

The redundant pane – which is located between the thermal and pressure pane – is also considered an inadequate redundancy for pressure pane failure.

“Analysis shows up to 70 percent negative margin of safety on redundant panes as a result of a dynamic failure at cabin pressure. Energy from pressure pane failure may be enough to break redundant pane Constitutes a catastrophic failure for the mission as thermal pane is not certified to hold cabin pressure.”

As to how the knob managed to find its way into the area between the dashboard closeout panel – which is the extension of the glare shield – and the window pane, changes in pressure for pre-launch to orbit operations, leading to the expansion of the orbiter’s skin, is once again deemed as the root cause.

“Crew module skin expands while in orbit due to 14.7 psi internal pressure; flight deck floor deflection may also contribute to the relative movement between the console’s dash and the CM window area,” added one presentation.

“Gap between the dashboard closeout panel and the window may have opened wider while in orbit (to accommodate the knob). Additional 7 psid and vibration from ferry flight might have wedged knob further. Gap reduced when CM (Crew Module) internal pressure reduced (descending). Knob is exerting a preload on pressure pane and closeout panel.”

An array of techniques have been listed as potential methods for removing the embedded knob from between the window pane and the console dashboard, although most are classed as holding risk of causing additional damage to the window – and are thus classed as last resorts.

“Pressurize Crew Module and use dry ice on knob: DeltaP from pressurization would be much less than seen on orbit (~3 psid instead of 14.7 psid). De-configure dashboard/console and instrumentation to free up knob. Use an air bladder between window and dash,” the presentation added.

“Cut knob enough to yield part. Cut out part of dash where knob is wedged: Would damage dash likely requiring repair. Cutting vibration could induce further damage to window. Use pry bar to deflect dash down: Viewed as the riskiest removal method for all hardware involved.

“Further damage could increase the potential for unacceptable damage, resulting in significant schedule impacts.”

The options relating to the application of dry ice to shrink the knob have already been attempted, and failed. However, the same method, along with a pressurization of the Crew Module, may be enough to free the knob from its lodged position.

The only problem is the amount of pressurization that can be conducted in the OPF is far less than the pressure that played a part in allowing the knob to become embedded in the first place.

“Pressurize crew module and dry ice on knob to TBD (To Be Determined) pressure. Pro’s: Could allow for uniform structural deflection to increase gap between pressure pane and dashboard; enough to free up the knob non-destructively. Less potential for inducing further damage to the pane.

**UPDATE: The above option was selected on Thursday as the opening process for an attempt to remove the knob. The cabin will be pressurized to 3 psid, before an engineer will apply dry ice to the knob. This option is not deemed to be a likely solution, but more so the opening option that avoids additional damage to the window.**

New article, click here:
http://www.nasaspaceflight.com/2009/06/atlantis-window-pane-begins-longerons-damaged-accident/

“Con’s: Maximum allowable pressure might be limited by crew module equipment and systems May not be able to exceed 3 psid; as compared to 14.7 psid nominal (orbit). May not be enough pressure to dislodge the knob.”

Removing dashboard and console components to free the knob from below the window is another option, but would lead to a large schedule impact for Atlantis’ OPF flow.

“Pro’s: Less potential for inducing further damage to the pane. If damage is found to be unacceptable, console is partially de-configured to continue with window assembly removal.

“Con’s: De-configuring console and instrumentation could represent a significant schedule impact. Influence of panel removal on the knob are not known at this time.”

A pressurized air bag method – involving one (or several) air bladders between window and the dashboard closeout panel adjacent to knob – could be used to apply pressure to deflect the dashboard enough to free knob.

However, without knowing allowable local pressure that can be applied, this technique could also result in additional damage to the window.

“Con’s: Risk of inducing additional window damage (TBD by Stress Group), not quantifiable. Current load on glass is unknown, additional load from air bladder may result in additional stresses to the glass.

“Not enough open surface adjacent to the knob for bag contact. Pressure may not be enough to deflect hardware and release the knob. Possible to inflict permanent deformation to dash secondary structure.”

A visit by the Dentist may prove to be a solution for Atlantis, via cutting the knob with a high rpm/low amplitude dental drill, just enough to allow for the knob to be freed from its current location. However, the vibrations from the drill may transfer to the window pane and again increase sustained damage.

“Pro’s: Method can be accomplished quickly. Does not involve manipulating window or dash hardware.

“Con’s: Potential for tool vibration to be transferred through knob into window induce additional window damage. Debris release from cutting. Knob would only be cut enough for tech to yield the piece.”

Vibration concerns are also cited for another option relating to cutting out part of dashboard structure where knob is wedged, while another option of using a pry bar to deflect dashboard structure down; enough to release the load imparted by the knob on the glass, again threatens further damage to the window pane.

Once the knob is finally removed – which has to be carried out – engineers will use their predefined criteria to hopefully clear the window for flight.

“After knob removal, will assess/evaluate window damage. Inspectors will inspect window per MT0501-514 requirements. Mold impressions, visual examination, etc.

“Stress evaluation will be required if surface damage reported is beyond the acceptable criteria 0.0015” for tempered panes or if bruising of glass has occurred. Unacceptable damage will require a window assembly R&R, significantly affecting the flow schedule. Bruised pressure pane will result in an automatic scrap.

“NOTE: Damage is in an area difficult to reach; if window inspectors are unable to assess the flaw, engineering is not able to perform an evaluation. Access to the lower region of the pane is limited and removal of crew module dashboard and panel structure may be required for proper assessment.”

For the interim, engineers will continue to meet, in order to discuss the best forward plan on removing the knob, before moving forward with the option that holds the least amount of risk of causing additional damage to the window.

“Removal of the knob is necessary in order to evaluate the condition of the glass for flight. Some of the options being considered involve risk to the hardware,” concluding the main overview presentation.

“Knob removal attempts should be performed by exhausting least risk options first. More evaluation is required.

“Forward Plan of Action: Will continue to evaluate and further develop these options and other feasible options in order to remove the knob with the least amount of impact to the hardware.”

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

No related posts.