Last week’s Space Shuttle Program (SSP) Flight Readiness Review (FRR) has approved the installation of a special minicam pointing out of window 4 on Atlantis’ flight deck. The camera will film the forward portion of the External Tank (ET) during flight, in order to capture the behavior of the LO2 Ice Frost Ramps (IFRs) during potential liberation events.
STS-129 Processing Latest:
Atlantis is continuing to track an opening launch date on November 16, with engineers completing the loading of hypergolics on the vehicle – known as S0024 operations.
Only one issue is in work, which will involve a memory dump on Atlantis’ Data Processing System (DPS).
“Orbiter: OV-104 / ET-133 / SRB BI-140 / RSRM 108 (Pad A) The team continues to work toward a target launch date for STS-129 of 11/16. APU (Auxiliary Power Unit) fuel load was successfully performed on Friday, completing S0024 Hyper Load operations,” noted the NASA Test Director on Monday processing information (L2).
“IPR (Interim Problem Report) (IDP 1 MIA word errors) update: DPS will perform a memory dump of IDP 1 today (Monday) was part of the troubleshooting for the word errors experienced last Friday.”
With processing proceeding to plan, engineers are pressing ahead with the start of orbiter closeouts, in tandem with retests on the recently replaced PV11 Fill and Drain Valve actuator on Atlantis.
“Call to Stations for S1287 orbiter aft closeouts will be performed today. Closeout activities will run all week,” added the processing update. “MPS (Main Propulsion System) PV11 actuator retest will be performed today.”
Foam loss events from the ET have been dramatically reduced since Return To Flight, mainly via a progressive effort to remove of foam from the most likely areas to liberate during ascent.
The LH2 ramps – located mainly on the midsection of the tank – were the main area of interest to engineers, following a number of liberation events during a number of flights. However, the removal of a large area of the foam mass from those ramps via continuous modifications has greatly reduced the threat of impacts to the orbiter.
The LO2 ramps – located on the upper part of the tank – became an area of added interest during the foam liberation events of STS-127, when one of the LO2 ramps liberated a relatively large area of foam during ascent. Liberation events from the LO2 ramps are less frequent than the LH2 – with STS-120 being the other other recent liberation event.
“STS-127-I-004 – ET TPS Loss at LO2 Ice Frost Ramp (IFR) 718. Foam loss at IFR 718 exceeds risk baseline,” noted the integrated IFA presentation for STS-127 on the first area of foam loss placed under focus.
“Associated Hazard Reports: IDBR-01 – Ascent debris impact to SSV (Space Shuttle Vehicle). Cause I – External Debris Impact to the SSV During Ascent. Due to ET Foam (PDL-1034/NCFI-26-007/BX-265 type of foam).
“Located at the LO2 Tank Ice/Frost Ramps and BX-265/BX-250/PDL-1034/NCFI-26-007 (type of foam) located on the LO2 Feedline Bellows PDL Drip Lip.”
A full outline of STS-127’s foam loss events – and opening mitigation efforts ahead of STS-128 – can be read here.
To add confidence the foam loss was a rare event, checks – including X-rays – were carried out on Discovery’s ET-132 ramps ahead of STS-128, in order to ensure the foam has no underlying problem.
“LO2 Ice Frost Ramp Loss: Additional NDE (Non Destructive Evaluation) options for ET-132 at KSC included X-ray and THz, (Good Results)” added the ET-127 IFA presentational to the PRCB (Program Requirements Control Board), noting good news on the health of ET-132’s ramps – and further mitigation on the downstream tanks in New Orleans.
As per usual, the engineers were proven correct, with ET-132 enjoying a flawless ride to orbit, with no foam losses of any note – leading to some comments ET-132 was the cleanest tank ever to fly with the shuttle.
However, NASA engineers still want to gain additional data on how the ramps behave during ascent, leading to the approval of a special camera, which will – for the first time – film the ramps during ascent from the point of view of the pilot’s window.
Normally, the view for the pilot out of the forward facing window 4 is obstructed by checklists and handbooks, as the crew concentrate on monitoring the vehicle mainly via instrumentation during the powered flight stage of ascent.
The new minicam will have one role, that of filming the view facing out of the window, capturing the front of the tank that protrudes into the view past the orbiter’s nose.
“SE&I (Systems Engineering and Integration) requested Orbiter explore camera locations to observe potential ET LOX Ice Frost Ramp debris,” noted one of 24 SSP FRR presentations available on L2. “Minicam installation near Window 4 provides field of view that includes top of ET (IFR 676 through 514 appear to be in view).”
Minicams regularly fly with the orbiters, including fixed camera facing both aft and forward of the crew cabin to capture the performance of the astronauts during the ride to orbit.
A handheld mincam is also used to film re-entry from the crew’s perspective – as seen on numerous two hour long videos obtained by L2 (free edited samples can be downloaded from an Atlantis re-entry – and an Endeavour re-entry).
The potential use of a minicam was first suggested ahead of STS-128, but too late to approve in time for installation on Discovery’s flight deck.
“Recent photos have been taken of the view seen of the ET from the pilot’s seat through window 4,” noted a memo outlining the plan back in August. “The photographs were taken in order to see the best location (best view of the tank as well as not interfering with the Pilot’s view) that a minicam could be mounted on the flight deck to monitor foam loss on the upper part of the tank during ascent.
“Further research and discussion will need to be completed before making a decision on the location.”
That research is now complete – mainly related to ensuring the minicam is safe to install – allowing for its debut on Atlantis for STS-129, with the subsequent video likely to be downloaded to the DAT (Damage Assessment Team) on Flight Day 2, adding yet more information on how the tank performed during powered flight.
“New location in front of Window 4 will follow standard installation method using bracket secured by Velcro, general purpose tape and tethers,” added the Orbiter SSP FRR presentation.
“Additional tethers will be used to assure no possible contact of the Minicam with Window 4 or the HUD should the Minicam come loose.
“Video/power cable will act as a tether should camera become released from the two integral bracket Velcro straps. Crew Compartment Configuration Drawing (CCCD) will be updated to include Kapton tape to assure bracket length adjusting screws remain captive.”
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.