Pad 39B suffers substantial damage from Ares I-X launch – Parachute update
Pad workers have begun to evaluate what is being described as substantial heat damage to Pad 39B, following the launch of Ares I-X. Meanwhile, the damage to Ares I-X’s First Stage was the result of splashing down at high speed and at an angle, due to only “one and a half” of its three main parachutes providing deceleration to the booster.
Ares I-X Parachute Failure:
Both the pad damage and the parachute anomaly should not detract from what was a successful test launch on Wednesday. All primary objectives were met, bar the parachute recovery system “Priority 4″ task, with managers noting their pleasure that the anomaly will provide important lessons learned for the Ares Program.
“The booster is in Port now and is being taken out of the water. It will be put on the rail dollies and dunnage and shimming added for support,” noted a memo acquired by L2 – which was written by Constellation management on Friday.
Recent – over the past one year period – Ares I-X Articles on NASASpaceflight.com can be found on this link:
“The team should get a first look at the riser lines Friday afternoon but it will be several days before the chutes are detangled and available for analysis. Likewise, the booster must complete safing before more detailed analysis of the hardware can begin.”
All that is known at this time is one of the three main parachutes failed after deployment and interfered with a second parachute – resulting in only one main chute being able to provide its full deceleration capability prior to splashdown.
“What we know currently is that almost immediately after main parachute deploy and prior to any reefing, one of the mains gives way on its riser lines and streams out,” added the memo.
“A cloud obscured part of the visuals during deploy but it appears that the streaming chute entangles with another of the mains, keeping it from full canopy. The result was only about 1 and 1/2 parachute capability for decelerating the booster.”
UPDATE: A follow up article will follow next week, following the acquiring of the full chase plane video (uploaded to L2 on Saturday) from ascent, staging, parachute deploy and splashdown. NASA has since released the video to Youtube on Monday.
Such incidents with the booster parachutes are not uncommon, with a loss of one main chute suffered by STS-128′s Right Hand booster, resulting in that booster hitting the ocean at a high velocity. However, it avoided any major damage.
“One of three RH main parachutes failed to fully inflate. Data Acquisition System (DAS) indicated failure occurred 3.9 seconds after frustum separation. Postflight inspection revealed damage on gore number 5 extending from above vent band to skirt band,” noted the STS-128 SRB IFA (In Flight Anomaly) presentation into the incident.
Unfortunately, with only one main chute operating nominally, Ares I-X’s First Stage not only hit the ocean at high speed, but also at an angle, causing it to buckle on impact – as seen in recovery photographs that circulated a number of sites on Thursday, including a high resolution set of images on L2.
“Photos of Ares I-X First Stage damage were taken by the USA recovery team. The ‘dent’ photos are actually of buckling of the booster versus denting,” added the memo.
“The buckling is a result of the hard impact of the booster with the water. The hard impact is the result of a main parachute failure. We do not yet know why the chute failed. That will take some time and in depth analysis.
“The booster both hit the water hard and at an angle. Buckling is to be expected in this situation. The photo of the fractured actuator bracket is also to be expected – the actuator bracket is designed to break loose on hard impact, thereby protecting the actuator from damage. The forward skirt extension that housed the chutes sank immediately upon water impact – as designed.”
Although the objective of Ares flights will be to recover and reuse the five segment boosters that will provide first stage power to the launch vehicle, the now-damaged four segment – and fifth segment simulator – booster from Ares I-X was never planned to be reused.
“As a reminder, the motor segments and aft skirt used for Ares I-X are retired shuttle assets and there was no intent to use them again. We will learn a great deal from this test flight anomaly – that is why we test!”
Interestingly, ATK – who build the boosters – were already aware of the threat of damage to the First Stage from increased splashdown loads on the larger Ares I five segment booster, and had been evaluating alternate stiffener configurations for the aft segment.
The mitigation also involved a proposed ETM-4 and ETM-5 as block upgrades to the five segment designs. ETM-4 would substitute an HTPB propellant formulation and a new strip wound insulation package. ETM-5 would be filament wound segments with metallic joints and dome segments.
In fact, the very notion of being able to recover the Ares I First Stage has been close to deletion since at least 2008 – part of the goal to save the mass involved for the recovery systems, as Ares I struggled to make up the performance shortfalls that has plagued the vehicle over most of its recent years of development.
Pad 39B Damage:
Engineers had already noted that Ares I-X would launch at a slight angle – only by a few degrees – in order to clear/avoid the Fixed Service Structure (FSS) at the pad, prior to the Thrust Vector Control (TVC) correcting the vehicle through the opening seconds of ascent.
The downside of such a flight profile results in the exhaust of the First Stage impinging on the FSS for a few seconds.
This concern was already well-known with the Kennedy Space Center (KSC) pad workers, with the main item of interest relating to a potential impact with the ET/IT platform area, which nearly led to its removal during shuttle to Constellation modifications to 39B.
In the end, Ares I-X departed the pad as planned, with the TVC ably controlling the vehicle away from the pad and into its correct flight profile.
Normally, a shuttle launch results in some burnt paint, blast effects on the MLP, an occasional cracked or broken gauge. However, 39B has suffered a large amount of damage from the heat and blast of the First Stage’s exhaust.
The first engineers to take a close look at the pad were those involved with the SCAPE (Self-Contained Atmospheric Protection Ensemble) operations, following damage to several hypergolic lines at the pad.
However, due to the impact of Ares I-X’s thrust on the FSS, the pad’s two elevators were both damaged, meaning SCAPE engineers had to climb three flights of stairs – in their SCAPE suits – in order to fix the hypergolic leaks.
One elevator has now been repaired, but the other will take “weeks” to fix due to the extent of what is being described as substantial damage.
While the 95′ level on the FSS suffers damage from almost every shuttle launch – since the Mobile Launch Platform 0′ level acts as a blast deflector – Ares I-X managed to impact the entire FSS on 39B.
All of the communication lines were destroyed during launch – along with all the outdoor megaphone/speakers melted beyond recognition – resulting in temporary communication lines being set up throughout the pad.
Heat damage has also been noted from the hinge columns through to the Rotating Service Structure (RSS), and a set of photographs acquired by L2 show extensive heat damage to nearly all areas of the vehicle-facing RSS.
Of course, Pad 39B won’t be used again for many years, with the next scheduled launch set to be the Ares I-Y test flight – although that vehicle is under severe and imminent threat of being cancelled, even if the Ares program survives the post-Augustine Commission decisions that will be evaluated by President Obama over the next few months..
The lesson’s learned from the damage to 39B will likely go some way into the forward plan for the largescale modifications to Pad 39B ahead of hosting Ares I launches, in order to keep maintenance and costs down between missions.
The final 39B configuration will include a massive rollercoaster EES system that will dominate the skyline as a fixed structure out at the pad complex.
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.