Centaur G/G Prime High Energy Upper Stage

[DaveS]

DaveS, just to be sure, the antennas on the Centaur don't deploy, right?

Yes they do. They're spring-loaded and deploy right at separation. This is mentioned somewhere in the Centaur G Prime Technical Description.

 

[GLS]

Yes they do. They're spring-loaded and deploy right at separation. This is mentioned somewhere in the Centaur G Prime Technical Description.

Then the question becomes: how do they deploy? Rotate 90º outboard? Up?

 

[DaveS]

Then the question becomes: how do they deploy? Rotate 90º outboard? Up?

They rotate 90° outboard.

---------- Post added at 01:25 AM ---------- Previous post was at 12:57 AM ----------

Correction to my earlier statement on the antennas: According to page 3-15 of the Centaur G Prime Technical Description they're spring-deployed after a safe separation distance from the Orbiter is achieved.

 

[GLS]

They rotate 90° outboard.

---------- Post added at 01:25 AM ---------- Previous post was at 12:57 AM ----------

Correction to my earlier statement on the antennas: According to page 3-15 of the Centaur G Prime Technical Description they're spring-deployed after a safe separation distance from the Orbiter is achieved.

Is 1 minute after separation enough?

 

[DaveS]

Yes, that should be enough.

 

[GLS]

Yes, that should be enough.

Thanks!
I'm just about to commit the changes.

---------- Post added at 01:39 AM ---------- Previous post was at 01:06 AM ----------

It's up!
I didn't use the Super*Zip Fire talkback as it really isn't needed, the crew looks out the window and if the Centaur is moving -> it worked. The panel operation is pretty simple.
The CISS positioning and the Centaur attachment was pretty much done by eye, so corrections will be needed (it also seems the Centaur doesn't quite fit in the CISS). The Centaur attachment positions should be correct.
The ACS nozzles seem to be off position as the coordinates are all symmetrical and on some nozzles it's visible the offset.
On the CISS animations... I tried but failed miserably as I don't know how, of if there's a way, to make variable speed rotations.

---------- Post added at 02:07 AM ---------- Previous post was at 01:39 AM ----------

There's a bug/typo in the STS-81I launch scenario, where the scenario starts at the launch time in the description. I don't know which is correct so can't fix it.

 

[DaveS]

I fixed the incorrect offset between the CISS and the Centaur. It was located too far aft, 15 cm to be exact. It now fits nicely. The TBs should all be used as they're tied into the orbiter's OI telemetry and therefore visible to MCC.

I also can't actuate the primary SuperZIP* ARM and FIRE switches. To separate the Centaur, I have to use the backup ARM and FIRE switches.

 

[GLS]

I fixed the incorrect offset between the CISS and the Centaur. It was located too far aft, 15 cm to be exact. It now fits nicely. The TBs should all be used as they're tied into the orbiter's OI telemetry and therefore visible to MCC.

Are the CISSs positioned correctly?

On the TBs, I fail to see the logic for having a fire indication TB, when this is something visible. If it was something out of sight, then it would make sense, but in this case if it fires, the Centaur moves, if it doesn't fire, the Centaur stays put. Plus, there's no fire TBs on the ASE panel, so I think my logic is sound.

I also can't actuate the primary SuperZIP* ARM and FIRE switches. To separate the Centaur, I have to use the backup ARM and FIRE switches.

It seems to be a(nother) VC issue. In the RMS station they don't respond (the whole top left area doesn't respond), but in the port WS all works well.

 

[DaveS]

Are the CISSs positioned correctly?

One good feature request for debugging the locations of payloads is the ability to set a specific set of actual shuttle-coordinates and having them displayed in-sim. I know the coordinates of all the trunnion/keel pins on the CISS/Centaur but have no way of knowing how they translate over to SSU. Another complicating factor is that I do not know the exact coordinates of the midbody payload umbilical panels on the orbiters, so their locations are best educated guesses.

On the TBs, I fail to see the logic for having a fire indication TB, when this is something visible. If it was something out of sight, then it would make sense, but in this case if it fires, the Centaur moves, if it doesn't fire, the Centaur stays put. Plus, there's no fire TBs on the ASE panel, so I think my logic is sound.

Well, the Centaur was a very different beast thanks to it's liquid cryogenic propellants and balloon-tank pressurization design. The crew and MCC really wanted all the insight they could get as well as lots of redundancy in the design which is why on the CISS all the ducts have dual valves so it's fault-tolerant. They did not trust the Centaur the way they trusted the solid propellant upper stages (PAMs and IUS).

 

[Urwumpe]

Well, the Centaur was a very different beast thanks to it's liquid cryogenic propellants and balloon-tank pressurization design. The crew and MCC really wanted all the insight they could get as well as lots of redundancy in the design which is why on the CISS all the ducts have dual valves so it's fault-tolerant. They did not trust the Centaur the way they trusted the solid propellant upper stages (PAMs and IUS).

Yes, but they did not design it unreasonable or wasteful, despite the astronaut office and a few engineers having concerns. Especially the separation systems had little need for additionally indications, because it is impossible to test anyway: How do you test, that a NASA standard initiator is really armed? All you can do is confirm that a switch had been correctly flipped.

And a solid upper stage has pretty little need for valves anyway.

 

[GLS]

One good feature request for debugging the locations of payloads is the ability to set a specific set of actual shuttle-coordinates and having them displayed in-sim. I know the coordinates of all the trunnion/keel pins on the CISS/Centaur but have no way of knowing how they translate over to SSU. Another complicating factor is that I do not know the exact coordinates of the midbody payload umbilical panels on the orbiters, so their locations are best educated guesses.

I glanced over the RCS mods Urwumpe did a while back and I think he added such a function. We could add a screen output for that.

Well, the Centaur was a very different beast thanks to it's liquid cryogenic propellants and balloon-tank pressurization design. The crew and MCC really wanted all the insight they could get as well as lots of redundancy in the design which is why on the CISS all the ducts have dual valves so it's fault-tolerant. They did not trust the Centaur the way they trusted the solid propellant upper stages (PAMs and IUS).

Even so, this is not Centaur specific. I remember reading in the Centaur Technical Description doc that "the Lockheed Super*Zip was the industry standard and was very reliable and such and such...", so I don't think this would be different from the IUS.
We could really do with a Centaur deploy checklist. I'm sure there were several back in 1985/86... hope they weren't all "lost" :facepalm:.

Anyway, is there anything that needs my immediate attention in the ShuttleCentaur branch? If not, then I'll go fix some more of my bugs in the ius-1.0 branch and then return to the trunk to play a little more in there.

 

[DaveS]

I glanced over the RCS mods Urwumpe did a while back and I think he added such a function. We could add a screen output for that.

A more graphical representation would be better than a debug string with just numbers.

 

[Urwumpe]

We could really do with a Centaur deploy checklist. I'm sure there were several back in 1985/86... hope they weren't all "lost" :facepalm:.

I am not sure if the Centaur program really progressed so far, that even preliminary checklists exist for it, a lot of it was likely still just getting developed while the astronauts prepared for the first Centaur mission.

 

[DaveS]

I am not sure if the Centaur program really progressed so far, that even preliminary checklists exist for it, a lot of it was likely still just getting developed while the astronauts prepared for the first Centaur mission.

Well, STS-51L happened in Jan. 1986, launches were scheduled for May 1986. The crews were definitely training for their missions. At L-5 months the FDFs are done, with only the occasional minor change happening. All the hardware&software existed (the GSE on both pads and MLPs had been installed). Atlantis was going out to 39A for a Integrated Tanking Test with a Centaur/CISS in February 1986 to validate the GSE and the Centaur/CISS.

 

[Urwumpe]

Well, STS-51L happened in Jan. 1986, launches were scheduled for May 1986. The crews were definitely training for their missions. At L-5 months the FDFs are done, with only the occasional minor change happening. All the hardware&software existed (the GSE on both pads and MLPs had been installed). Atlantis was going out to 39A for a Integrated Tanking Test with a Centaur/CISS in February 1986 to validate the GSE and the Centaur/CISS.

So somewhere at the JSC, the checklists might be archived on microtape.

 

[GLS]

So somewhere at the JSC, the checklists might be archived on microtape.

Looking at how NASA treats its history, I wouldn't be suprised if it all was "lost". :facepalm:

 

[Urwumpe]

Looking at how NASA treats its history, I wouldn't be suprised if it all was "lost". :facepalm:

What was ever all lost? Aside of the printed versions of the Saturn V blueprints?

 

[GLS]

What was ever all lost? Aside of the printed versions of the Saturn V blueprints?

Didn't they overwrite the Apollo 11 EVA video tapes?

 

[Urwumpe]

Didn't they overwrite the Apollo 11 EVA video tapes?

Not that I know. The story was different.

http://www.parkes.atnf.csiro.au/news_events/apollo11/The_Apollo11_SSTV_Tapes_Search.pdf

 

[GLS]

Not that I know. The story was different.

http://www.parkes.atnf.csiro.au/news_events/apollo11/The_Apollo11_SSTV_Tapes_Search.pdf

I did a "fast read" of that, and at the time it was written they were still searching for the tapes. According to this reliable website :lol:, in 2009 they determined that they were overwritten. :facepalm: