NASA Releases Failure Report On Outback Crash

cybrpnk2 writes "In a Friday news release, NASA Goddard Space Flight Center has issued Part 1 and Part 2 of an excellent and very interesting failure review on the April 28 failed balloon launch of the Nuclear Compton Telescope at Alice Springs, Australia. Bottom line: make sure you don't need a gorilla to pull the payload release handle at balloon launch; if the release mechanism does fail then make sure your safety cables are sized for lift loads and a swinging payload, not just static hanging payload weight; and oh yeah — keep people and vehicles out of the downwind flight path. One spectator was nearly crushed while running from his SUV that was hit and flipped (Figure 29, Vol I). At least nobody ordered video evidence destroyed."

Comments

In Sum

[Mikkeles]

Hire a competent engineer to design your balloon!

Re:In Sum

[Kell Bengal]

Well, in fact, it's not that simple. I worked for a time with an engineer who did exactly that - balloons and apparatus for radio astronomy. He often told me of how complex and dangerous this process is. This is hardly the first launch mishap of a radio astronomy balloon, and it won't be the last.

Even with the very best balloon design, the very best tethers and the very best launch protocol, if the wind turns on you unexpectedly, everything can be lost in an instant. This crash wasn't negligence or even direct human error in design or execution, it's just a confluence of things (some foreseeable, some not) that lead to a failure. It happens, especially in experimental work.

I don't know why TFS is contrasting the accident report to a soldier being ordered to delete footage - what does this have to do with the story?. After all, it's not like NASA has a history of erasing important footage or data.

Re:In Sum

[Chuckstar]

The report may not use the word "negligence", but if you read it, you'll see they come down pretty hard on the balloon program for not taking the proper precautions to avoid an accident. How that differs from negligence, I have no idea. Here are just a few of the findings that led to that conclusion:

- Suggestions developed from the investigation of a crash in 2002 were ignored.

- NASA's requirement to have a range safety officer independent of the program were ignored.

- A variety of other safety guidelines were ignored.

- Culture in the balloon program was that balloon launches are straightforward and nothing could go wrong, in spite of a history of mishaps.

A few quibbles

[Gadget_Guy]

First, an Australian wouldn't call the car involved an SUV, but rather a 4WD (4 wheel drive).

Secondly, it doesn't seem like an amazing story. They saw some spectators were in the way, so they tried to quickly move it all and they had problems doing this. The only real concerns that I had with the operation was lack of direction given to the spectators as to where they should go to stay out of harm's way and the campaign manager not being organised enough to know the emergency services number in Australia. No, it is not 911. It is also not what they said it was in the NASA report "0". It is in fact 000 or 112 if you are using a mobile (cell) phone.

Finally, what is with the trolling in the summary about video evidence being destroyed. That has nothing to do with this story.

What Video Evidence?

[jshackney]

Am I the only one who expected the final link of the summary to take me to video of the mishap and not some crap about the Ft. Hood shooting?

Re:Link?

[jshackney]

Here's one:

http://www.youtube.com/watch?v=AoNVCqUMW4A

On the 50th Anniversary of the Nedelin Disaster

[eldavojohn]

and oh yeah — keep people and vehicles out of the downwind flight path

Thankfully no one was seriously injured or killed. It's been fifty years today since the infamous Nedelin Disaster happened at the Baikonur cosmodrome. It shocks me that as recently as 15 years ago these sort of catastrophes happened.

At least nobody ordered video evidence destroyed.

Given the above incidents and their cover-ups, I'd agree. We must study these mistakes, own up to them and learn from them.

Maj. Hasan video has what to do with what now?

[DNS-and-BIND]

Excuse me, but can anyone tell me the significance of the link to the soldier who was ordered to erase the video of Major Hasan's murders? This has what do with NASA now? The video was erased because it wouldn't look good on the evening news to show him shouting 'Allahu akbar' as he killed American soldiers. Or is this just some sort of post-ironic offhand hipster comment that nobody can understand, including the story submitter?

It's surprising that they expected this to work

[Animats]

After reading through the whole report, the most surprising thing is the design of the launch mechanism. The basic setup was that the launch was done from a moving crane truck. The truck was equipped with special outrigger wheels, so it could handle some side load without rolling over, and a platform for the "launch director", who was supposed to release the payload by yanking on a strap attached to a cable, pulley, and pin. The launch setup is that the balloon is inflated, allowed to rise, and then the crane truck. which is carrying the payload, tries to get under the balloon, chasing the balloon if necessary. When the payload is in position, the launch director yanks the strap and releases the payload.

This is obviously a setup which is highly dependent on what the wind does during the launch process. Some of the time, the wind is not going to cooperate, and an abort will be required. That's to be expected. But this time, they didn't abort until it was far too late.

During the process of chasing the balloon, the stresses on the restraint system were about 3x higher than at rest. It would have taken a 300 pound pull to release the pin; this was tested after the event. The guy who was supposed to pull the strap, while standing on a moving platform atop the crane truck, wasn't even wearing gloves. There was no backup system for releasing the payload. The payload eventually released when the crane truck reached the airport perimeter fence and had to stop. The wind forces from the balloon were then great enough to tear off a mounting plate on the truck, releasing the payload, which plowed through the fence and wiped out an SUV.

They didn't have an explosive bolt system to release the payload. The launch system used remote controlled pyrotechnics for releasing the balloon's restraining ring, and for the balloon-release abort system, so they already had all the systems and procedures in place for using pyrotechnics. But the main launch function was a guy pulling a strap.

There's clear video of the incident. This is useful to watch. When the payload tears loose from the crane, the crane truck is facing 90 degrees from the wind direction and stuck at the fence line. The crane boom is under high sideways stress. The abort system should have been triggered when the truck got into that situation, but it wasn't. (An abort prior to release loses the balloon and saves the expensive payload.) But the person with the abort button (the "campaign manager") and the guy trying to pull the release strap (the "launch director") were in different places and not coordinated, so when things went wrong, the abort didn't happen until after the payload had come loose and wiped out the perimeter fence and an SUV.

Re:It's surprising that they expected this to work

[Animats]

A video that shows a second or two before the payload broke loose yields more information. It looks like the crane truck was starting a left turn, pulling against the balloon, when the pull from the balloon broke the attachment to the truck. The previous video made it look like the balloon was pulling the crane boom sideways, and the boom snapped back after release. But no. The truck was doing a left turn (they had to do something, they'd reached the perimeter fence) while the balloon pulled it to the right. That's where the big stress came from.

If the plate on the crane holding the cable to the balloon (safety factor 1.3, far too small, as later computed by NASA) hadn't failed, the launch team would have been able to hold the balloon and save the payload. They'd had failed launches before, and knew the truck was heavy enough to hold the balloon. So one can see why they held off on an abort. They might have been able to back the truck out and try the launch again. But their crane rigging wasn't built for sizable side loads.

In retrospect, they should have aborted sooner. The payload is the valuable part; it's normally recovered by parachute. An abort would have saved the payload and lost the balloon. The balloon is a consumable. But, as NASA's critique points out, they didn't have formal abort criteria, and tried an ad-hoc fix to get out of the mess they were in. If the bolts on the crane's attachment plate had been stronger, it would have worked.