On Thursday, February 15, 2018 at 4:26:46 PM UTC, krasw wrote:
torstai 15. helmikuuta 2018 15.29.25 UTC+2 kirjoitti:
Now tell me again...
Why aren't the O rings on the probe?

Must be an oversupply of engineers needing to design something like this O ring insertion tool.

If the grooves for O-rings were in the probe it becomes quite weak at the base. Aluminium or brass develops crack at groove area because TE probe vibrates a lot. My guess: they discovered that probe with O-rings/grooves did not last too long. BTW, one-way TE probe has usually a groove and O-ring in the probe. It cracks sometimes but it is easy to glue a new base part to an old probe. With two- or 3-way probe this is impossible.

That makes sense. Unlike the triple probes the ESA TE/Static double probes use the ST2 socket and the probe has a short aluminium (I think) insert with O -rings on it. I had one of those break in flight at an O-ring groove inside the socket. Part way through the task I lost the ability to thermal properly and didn't understand why until I landing and found the probe drooping about 30 degrees and being held by the probe internal flexible tubing..

I contacted ESA directly and they repaired the probe very quickly for a very reasonable cost.