Space Shuttle Ultra 1.25 Revision B development

[Urwumpe]

Well, I ran an MC integration using ShipEdit on the left-hand SRB and plugged in the new PMI and cross section values, with no change at all.

I have attached a screenshot of the LH SRB with the thrust vector activated. Does it look good to you?

The magnitude yes, should be approximately 8 x 20,000 lb(f). But the rotation is caused by torque, not the linear force that attaches to the CoG.

 

[DaveS]

The magnitude yes, should be approximately 8 x 20,000 lb(f). But the rotation is caused by torque, not the linear force that attaches to the CoG.

OK, torque screenshot is attached.

 

[Urwumpe]

1.225 MNm pitch moment????

That is damn huge...

 

[DaveS]

1.225 MNm pitch moment????

That is damn huge...

It is. So something is off! I have checked in my current SRB sources and a SRB sep test scenario.

 

[Urwumpe]

It is. So something is off! I have checked in my current SRB sources and a SRB sep test scenario.

I have found the TM that contained the specifications for the separation system, NASA TM-X-64967. It also contains the precise positions of the BSMs in Figure 1.

Each BSM has 0.75 seconds web action time and 0.125 seconds tail off, with 0.125 seconds ignition delay, four BSMs should produce 74667 lb(f).

The pitch rate is about +5.0° after 3 seconds.

The roll rate should be -9.15°/s 3 seconds after separation, and the roll should be about 33.7°

 

[DaveS]

I have found the TM that contained the specifications for the separation system, NASA TM-X-64967. It also contains the precise positions of the BSMs in Figure 1.

Each BSM has 0.75 seconds web action time and 0.125 seconds tail off, with 0.125 seconds ignition delay, four BSMs should produce 74667 lb(f).

The pitch rate is about +5.0° after 3 seconds.

The roll rate should be -9.15°/s 3 seconds after separation, and the roll should be about 33.7°

Verified the positions and angles given in TM-X-64967 and they all appear correct.

Just for the heck of it, I calculated the direction vectors for the aft BSMs of 40°s in the pitch axis as outlined in that document and while the roll-rate did decrease to something closer to the real value, the pitch rate was nowhere near the real value. I think it was just 1.5°/s vs the 5°/s you quoted.

Should I check in the current Atlantis_SRB.cpp I have with the new aft BSM thrust direction?

 

[Urwumpe]

Should I check in the current Atlantis_SRB.cpp I have with the new aft BSM thrust direction?

If it works - yes.

 

[DaveS]

If it works - yes.

Checked in.

 

[SiameseCat]

This is a complicated issue. The CT is like an old-fashion rail-road train in that the initial acceleration is very very slow. It takes some time for the CT to begin moving as first motion is barely detectable if you look on the belts. Actual motion of the CT after you have commanded it to move is lagged by around 5 seconds.
The first sign that first motion have been commanded is that the discs on the drive trucks begin to spin up after which the CT begins to move.

Then there's the issue of stopping the CT, which it again is like a rail-road train, in that it doesn't come to a complete stop even if you commanded it to. Distance traveled during that time is about 60-100 ft.

I've checked in an updated version of the crawler, which accelerates/brakes more slowly.

For the SRB sep, the Right SRB has a pitch rate of 1 deg/s and a yaw rate of 0.5 deg/s. The Left SRB however, has a roll rate of 13 deg/s. Have you updated the BSM positions for both SRBs?

 

[DaveS]

For the SRB sep, the Right SRB has a pitch rate of 1 deg/s and a yaw rate of 0.5 deg/s. The Left SRB however, has a roll rate of 13 deg/s. Have you updated the BSM positions for both SRBs?

No, just the left.

---------- Post added at 07:18 PM ---------- Previous post was at 04:37 AM ----------

Got a chance to try out the new crawler engine code and it behaves much more realistically for a vehicle of its size and weight!

BTW, any new developments on the LDS display? I know Urwumpe was interested in taking a look at it.

 

[Urwumpe]

BTW, any new developments on the LDS display? I know Urwumpe was interested in taking a look at it.

Yes, but I didn't find much about it. I wasn't even able to get manufacturer information.

 

[Donamy]

Anyone looked at the SSME stowing on orbit, or the KU gimbaling ?

 

[DaveS]

Yes, but I didn't find much about it. I wasn't even able to get manufacturer information.

Too bad. You haven't found anything on the VAB cranes have you? I'm in short supply of reference materials on the VAB cranes.

---------- Post added at 08:29 PM ---------- Previous post was at 08:24 PM ----------

Anyone looked at the SSME stowing on orbit, or the KU gimbaling ?

That would be fantastic to have. This is something that should be implemented, the Ku antenna dish spinning wildly after the RPM:

for all the RPM's up thru STS-128, the Ku was taken to AUTO track as well for the same reason. As the Ku would break lock after about 180 degrees through the rotation (starboard door gets in the way). The Ku at that point then remains pointed towards a fixed location inertially. Once the Ku is placed back into GPC after the RPM completion, the search automatically begins - initially pointing the dish to where the onboard relative state believes the target to be located, and then spiraling out from there in search of the target.
As of STS-129 though, the Ku is now placed in Standby mode just before RPM start, hibernating the entire system through the RPM, before returning power after RPM completion.

 

[Donamy]

Drawing a blank here. Can anyone tell me the key presses for mid-deck view for latest release?

 

[DaveS]

Drawing a blank here. Can anyone tell me the key presses for mid-deck view for latest release?

Head over to the port workstation view and then press Ctrl-Down arrow.

 

[Donamy]

Thanks, so the view is not of the seated astronaut ?

 

[DaveS]

Thanks, so the view is not of the seated astronaut ?

No.

---------- Post added at 02:16 PM ---------- Previous post was at 02:49 AM ----------

CT-1 tour, July 2000:

Part 1:

Part 2:

Part 3:

---------- Post added at 10:12 PM ---------- Previous post was at 02:16 PM ----------

So what do you think? Are the videos usable for us to get a pretty good idea on how the Crawlers actually work?

 

[Urwumpe]

So what do you think? Are the videos usable for us to get a pretty good idea on how the Crawlers actually work?

I Think so, but I just managed to get to the second video yet, since I am at home.

 

[DaveS]

I Think so, but I just managed to get to the second video yet, since I am at home.

I think that the CT might be a perfect test vehicle for the comm system as operating the CT is very much a team effort between the engineers in the Engineering Room, the drivers in the two cabs and the outside observers on the CT as well in the VAB or at the pad.

 

[Urwumpe]

I think that the CT might be a perfect test vehicle for the comm system as operating the CT is very much a team effort between the engineers in the Engineering Room, the drivers in the two cabs and the outside observers on the CT as well in the VAB or at the pad.

Great idea... could maybe be simpler than in the Shuttle.

Can you get some more data on the operations?

And for something else: Can you produce a KSC worker mesh? with a small radio comm in his hand? So we can visualize the observers