Boeing's Starliner rolled off launch pad to replace 'buzzing' rocket valve (photo)

[Admin]

Boeing's Starliner spacecraft was rolled off the launch pad today (May 8) to replace a misbehaving valve on its Atlas V rocket.

Boeing's Starliner rolled off launch pad to replace 'buzzing' rocket valve (photo) : Read more

 

[billslugg]

I will assume, for this comment, we are dealing with a standard concept, a disc held in place by a spring pushing on it. Such a valve will lift when popped, stay slightly open until the pressure drops a bit then reseat once the excess pressure is relieved. In order for the valve to chatter, something has to be bad wrong somewhere, and it might not be the valve. It could be an obstruction which limits flow to the valve.

 

[CraigofTruth]

It seems to me as a complete novice that Boeing along with United Launch Alliance are playing with fire by using inferior valve systems. Like the saying goes, "Penny wise but (Pound) Dollar Foolish" in Boeing and United Launch Alliance's case it is, "Hundreds of Dollars saved but Millions of Dollars foolish."

 

[bolide]

It seems to me as a complete novice that Boeing along with United Launch Alliance are playing with fire by using inferior valve systems. Like the saying goes, "Penny wise but (Pound) Dollar Foolish" in Boeing and United Launch Alliance's case it is, "Hundreds of Dollars saved but Millions of Dollars foolish."

Amazing that, from your armchair, you can deduce that the problem is "using inferior valve systems." Have you contacted ULA about this?

 

[Unclear Engineer]

OK, let's get real, here.

The relief valve with the problem is on the Centaur upper stage and is used to vent the liquid oxygen tank to limit pressure. It is specifically designed for that function, and is not just a simple disk and spring assembly - it has a geometry that is designed to be stable during venting and have a high reliability of sealing when reseating. Liquid oxygen has long been used as the oxidizing propellant in rockets, so this is not likely to be some sort of new design problem.

The Centaur upper stage was designed by Convair/General Dynamics and later Lockheed-Martin. So, it comes to the Boeing/Lockheed-Martin "United Launch Alliance" from the Lockheed Martin side, not the Boeing side. It has been used for many tasks in many variants for a long time. See https://en.wikipedia.org/wiki/Centaur_(rocket_stage) .

The long and detailed pre-launch "count-down" process is specifically designed to deal with the "s__t happens" aspects of flying rocket vehicles. This just looks to me like another example of finding a problem before liftoff and fixing it. The goal is a safe flight for the astronauts, not meeting some "do or die" schedule.

So, I do not see any reason to blame Boeing for this particular delay.