This is probably a manufacturing/materials quality control issue. Nothing world-shaking but I'm sure PWR will be required to undertake either extra checks or closer checks on the RL-10B-2 nozzles for a while.
This is probably a manufacturing/materials quality control issue. Nothing world-shaking but I'm sure PWR will be required to undertake either extra checks or closer checks on the RL-10B-2 nozzles for a while.
Considering on the Delta III flight 2 failure they had X-Rays that showed the defect area. It would not have taken so long to assign a root cause if the defect(s) had shown up in the X-Rays and pre-flight inspection records. Something more complex than a simple QC issue is at work here.
So, the essence of this is that there was a leak in the main engine nozzle just above its narrowest point that would have meant reduced thrust. I presume that it would have also meant a permanent hard-over TV in the opposite direction to stop the vehicle being forced off course by the exhaust leak, further reducing the energy delivered along the long axis. Am I correct?
Some more details on the failure investigation and results...
http://spaceflightnow.com/delta/d361/investigation.html
This article states: "Those potential causes common to both vehicles have been put to the test against the Atlas engine that will power Tuesday's launch of the X-37B spaceplane, known as Orbital Test Vehicle Flight 3, and officials Friday formally cleared that RL10A-4 for flight."
But an article in Av Week (arrived today, can't find it online yet) was less sanguine. I stated (more or less) that it was "formally cleared" by waiving the requirement that the last failure be understood, and simply taking your chances. It said each customer had this option, and that NASA had already accepted it for the January TDRS flight.
satellite owners are proceeding with [...] EELV missions only if they are willing to accept any extra risk resulting from the unknowns surrounding the incident"
The Air Force launched [...] only after acknowledging "acceptable risk" [...] "Each mission owner makes their own determination [...]" NASA has likewise agreed to launch its next satellite...
"We have to find what happened and why, because there is no Plan B," Sheldon said.
One would have to think this situation gave some impetus towards granting SpaceX qualification flights for military contracts.
One would have to think this situation gave some impetus towards granting SpaceX qualification flights for military contracts.
There is no connection. New govt contracts requiring a down select, take more than a year.
Also, if following that line of reasoning, then Spacex is not worthy alternative since they have issues too.
One would have to think this situation gave some impetus towards granting SpaceX qualification flights for military contracts.
There is no connection. New govt contracts requiring a down select, take more than a year.
Also, if following that line of reasoning, then Spacex is not worthy alternative since they have issues too.The "situation", one upper stage engine that, if stood down, could stop all launches, has existed for much more than a year. At least some folks had to have been thinking, "What if the RL-10 is grounded?". The recent problem should (I hope) just be demonstrating that people were right to be worried.
And as far as SpaceX being a worthy alternative, even if they too are grounded sometimes, it's still better than a single point of failure. Of course it's not yet proven they can do the job.
There are more Atlas folks going forward than Delta folks.
Can you explain how you are sure of your statements?
Can you explain how you are sure of your statements?
If this post was directed to me, I'm not absolutely sure but I think that it's common sense. Customers would be less willing to take a change with the same engine model that failed. Another engine model of the same family is still increased risk, as there is likely component production common to both, but the risk is still reduced compared to the actual type that failed.
There are more Atlas folks going forward than Delta folks.Makes sense. After all, RL-10B-2 is the engine under investigation; RL-10A-4 is related but not identical.
There are more Atlas folks going forward than Delta folks.
Makes sense. After all, RL-10B-2 is the engine under investigation; RL-10A-4 is related but not identical. I'm sure it's from a different production line and therefore is less likely to be affected by whatever really happened here.