Posted on 10/29/2014 3:09:10 PM PDT by BenLurkin
As investigators began their work, they will be looking at the explosion of an AJ-26 engine – the same model as the two propelling the Antares rocket – during tests at Nasa's Stennis Space Centre in Mississippi in May. The AJ-26 engines were built by Soviet scientists for their failed Moon exploration programme in the 1970s but then mothballed for decades. They were subsequently bought and refurbished by a US company and have been used successfully in several rocket launches.
...
Investigators from the US government and the rocket company Orbital Sciences have given no indication yet of what caused Tuesday night's explosion of the $200 million (£125 million) Antares and its 5,000lb cargo. Asked about the possible role of the engines, Frank Culbertson, Orbital's vice-president, said: "We need to go through this investigation and be very thorough before we determine whether that's a factor in this or not."
The age and origin of the refurbished engines were already under scrutiny.
...
Mr Culbertson urged curious onlookers and local people to stay away from the accident site and not to touch debris or try to pick up souvenirs.
"The investigation will include evaluating the debris that we will find around the launch pad and everything associated with that," Mr Culbertson said.
"I do want to caution the public, this is an accident site and it's a rocket and it had a lot of hazardous materials on board that people should not be looking for or wanting to collect souvenirs over. If you find anything that washes ashore in the local area or came down in your farm or in your yard, please make sure that you call local authorities."
(Excerpt) Read more at telegraph.co.uk ...
no kidding
was it carrying something else capable of exploding?
Is it possible the thing that regulates the thrust, over-thrusted? 108%?
The video showed a leak, followed by insufficient thrust, followed by earth impact and subsequent large explosions.
I was going to post this ‘Orbital’s Soviet Rocket Engines Had Already Been Slated for Retirement” http://www.businessweek.com/articles/2014-10-29/orbital-antares-had-soviet-rocket-engines-slated-for-retirement
but I think FR guidelines say that publication is a no-go.
Plus, I suppose somebody could detonate a rocket like Antares if they put a tracer round through it — but we’d need to hear form the FRengineer FRexperts on that.
An earlier article said they MODIFIED them to fix the previous known problems with the engines.
If I were the Russians, I would have a way of destructing those rocket engines implanted, because they can.
Hazardous materials on board?? And they’re delivering them to the Russian astronauts?? That doesn’t sound right.
There is no good reason the US cannot built its own engines
My guess, as a sofa slug, life long launch watcher (with no engineering qualifications) — is that one of the nozzles fractured or separated thereby causing the engine to combust without containment (the brief bright flare) Shortly thereafter this caused fuel in the feed lines to detonate (the mid-air explosion) and after that the stack dropped onto the pad and couldn’t help but explode the remaining fuel.
The engines may have hit the base of the launch tower just as it lifted off
Like, say, a tank full of rocket fuel and/or oxidizer or the connecting piping, valves, regulators, fittings, etc.?
Good analysis possibility. Having watched the video a number of times, there is a brief change in character of the thrust (more opaque, brighter), followed by a small explosion at the base of the rocket, then loss of thrust, descent and large explosion upon impact. The problem sure seems to be at the base of the first stage.
was it carrying something else capable of exploding?
I haven't seen closeups of the video but another cause could be a fuel tank leak. Start dumping a few hundred gallons of hydrogen or oxygen onto the outside of a hot engine and you could have an explosion that's not the engine's fault.
Since it was the engines and all that blew up ....
Some of the engines to maneuver the craft in orbit can have pretty nasty fuels and oxidizers. You wouldn't want to poke a tank of them if they survived the explosion somehow.
I was considering the fuel as part of the engine I guess
I am still thinking loss of liquid oxygen feed, whether a leak or a turbopump failure. The bright flash at the beginning of the failure could be from the loss of pressure in the combustion chamber. On descent, there are still flames from the engine, but not with the structure, more like just fuel (in this case kerosene) pouring into the chamber. Upon returning to the launch pad, the fuel and oxidizer tanks ruptured for the final explosion.
Orbital likes to use refurbished ICBM engines. The “Minotaur” series of rockets use Minuteman II engines. I believe they have a dozen or so launches of those with zero failures.
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