aoh-v1-2-09-seqsys.pdf page 31 implies that those switches are the only way to jettison the LET. The pushbutton fires the escape tower main motor if the seperation motor fails to fire, but it still has to be seperated first using the switches.
Hi Movieman and Tschachim!
I'studied the doc you mentionned and you're perfectly right and I was wrong! I was surprised to discover that the LET was jettisonned manually but documents are incontestable.
Sorry to be so narrow-minded
Problem is, it's a massive change because there's no support at all for having the LET attached after SII seperation. Really we need to replace all the SetStage() functions with one single function which takes a structure with a bunch of flags about the current state and sets up the meshes appropriately... as I said in the other thread in Planning, that's probably something for 7.1.
I've just had an idea for an intermediate and temporary solution which is maybe simple and easier to do:
This morning I launched a launch scenario to try to jettison the tower manually. So, just after the SII ignition I switched the 2 buttons on UP position but nothing happened... I waited a few minutes for the automatic jettison and ... the LET stayed in place: My switches were still on OFF position, so I switched back to AUTO, and then the LET immediately fired and separated automatically.
That gave me an idea :idea:
Would it be possible just to invert the switch positions?
I mean that we let the switches on AUTO for launch like Checklist says but if the AUTO position is actually wired to OFF for the internal system and the OFF position wired to AUTO, when time has come to switch to the UP position the system understands in fact "AUTO" and then the LET jettisons automatically but looks like the system is working manually.
I hope you understand me because I'm not sure to be clear...
In fact, with this feature we only lost the ability of an automatic jettison following an abort, because the switches in virtual AUTO position would actually be in OFF. But, according to the Apollo 15 Check list, during any abort mode using the LES (1A, 1B and 1C) it is asked to the astronaut to take the TWR JETT switches on UP position, probably for redundance. So if we follow this procedure we keep the ability of a tower jettison which is in fact the most important. And everybody knows that critical launch failure are very rare in NASSP (for the moment
Would it be difficult to do such a release?
You know I'm the worst informatician of the world (in fact not an informatician at all), so it's far beyond my skill to do that work!
I even don't know if it's possible?
If not, no matter, we can let this feature in its state for the moment. After all, compare to the entire flight, LET jettison is just a small detail...
It was just a suggestion, an idea...