Orbital Sciences rocket explodes on launch

[Jammrock]

https://www.youtube.com/watch?v=jHMmMgdcOSU#t=30

That's a big boom.

[KRSESQ]

That's gonna leave a mark. :/

[paulw]

Pleaze explain coming up.

[Dr Mordrid]

During the launch, what there was of it, it looked like one engines plume went yellow indicating the mixture went fuel-rich. That indicates a problem with the LOX system which could mean a blockage, burst line or, perhaps most likely, the engines turbopump came unglued.

Orbital Sciences is an old style aerospace company of long standing; horizontally integrated, they contract out for components then integrate them into a system. This in contrast to SpaceX, where raw materials flow into one end of their Hawthorne plant and rockets & spacecraft come out the other.

The engines on Antares are Russian-made NK-33's, which were made >40 years ago as upgrades for the Soviet N1 moon rocket. It was cancelled after 4 launch failures, ending their lunar program.

The NK-33's were stored in.plastic bags until they were bought by RocketPlane-Kistler for their Commercial Cargo program. When RpK went belly up because of missing NASA milestones, Orbital Sciences bought their engine contract. They contracted Yuzhnoye SDO in Ukraine to build the first stage; tanks, mounts, wiring etc.

Orbital contracted Aerojet-Rocketdyne to refurbish the engines for use, redoing their wiring harnesses & mounts, and relabeling them as AJ-26 to mask their heritage. Several were found to be corroded and discarded. Aerojet-Rocketdyne certified many for flight. They may regret that.

One caught fire on a test stand before the first Antares launch. There were 3 successful Antares flights, using 2 NK-33's each, before another engine exploded on the test stand last May. Orbital kept flying, launching a 4th Antares successfully before #5 exploded Tuesday.

Many people think the corroded engines should have been a clue that the complex metallurgy and coatings were deteriorating and not to be trusted, Elon Musk making the engine point in a 2013 issue of Wired.

It's clear Orbital wanted to rid themselves of the NK-33's but faced challenges in doing so. ULA wouldn't sell them RD-180's obtained from Russia, and up to now there haven't been US engines of this class - which is changing but not fast enough for Orbital's problem.

Even though Orbital is in the process of merging with ATK, maker of the Shuttle and SLS SRB's, using an ATK solid lower stage presents problems; their pad at Wallops couldn't handle the stresses of launching large solids, and they present range safety issues at Wallops.

The military would call the whole mess a Charlie Tango.

[Dr Mordrid]

A great view from 3,000 feet

[MultimediaMan]

A RUD event for certain.... it will not buff out.