-
#40
by
Ben the Space Brit
on 24 May, 2013 12:49
-
Is the 9450 the most commonly used version of the Delta?
least and tie for least after this launch
Who calls it a "9450"? ULA doesn't on their web site or in their literature.
- Ed Kyle
Isn't that the Boeing model number?
-
#41
by
PahTo
on 24 May, 2013 15:00
-
Do all four SRMs ignite for/at liftoff? I imagine even if they do all fire at the same time, they are jettisoned 2x2 in a staggered fashion (diametrically)--true?
I don't think I've ever seen this config--should be fun this evening!
-
#42
by
jacqmans
on 24 May, 2013 15:02
-
-
#43
by
ugordan
on 24 May, 2013 15:03
-
Do all four SRMs ignite for/at liftoff? I imagine even if they do all fire at the same time, they are jettisoned 2x2 in a staggered fashion (diametrically)--true?
I don't think I've ever seen this config--should be fun this evening!
4 SRMs: http:
//www.youtube.com/watch?v=1bUOT_jcYjE
-
#44
by
PahTo
on 24 May, 2013 15:17
-
Thanks ugordan.
-
#45
by
00rs250
on 24 May, 2013 15:29
-
Well, my statement from yesterday is an understatement for today!
-
#46
by
jacqmans
on 24 May, 2013 17:02
-
InsideKSC@InsideKSC
Your 11 a.m. Delta IV #WGS5 launch status update: pic.twitter.com/isT1Oaq5dH
-
#47
by
jacqmans
on 24 May, 2013 18:32
-
The team has the "Go" to begin cryogenic fueling operations on the #DeltaIV with #WGS5.
-
#48
by
Chris Bergin
on 24 May, 2013 18:49
-
-
#49
by
Prober
on 24 May, 2013 18:53
-
-
#50
by
PahTo
on 24 May, 2013 19:59
-
Follow-up per Mr. Graham's wonderfully detailed article, and per jacqman's image a page back (div_wgs5_r5)--it appears the SRMs are indeed different--may just be camera angle, but...
Do the TVC-equipped SRMs actually burn slightly longer? If so (and maybe even if not), I assume they assist with mitigating transients resulting from the first set of SRMs separating.
Is TVC electro-mechanical as it is with Castor30?
Best wishes for a successful mission!
-
#51
by
Jim
on 24 May, 2013 20:11
-
1. Do the TVC-equipped SRMs actually burn slightly longer? If so (and maybe even if not), I assume they assist with mitigating transients resulting from the first set of SRMs separating.
2. Is TVC electro-mechanical as it is with Castor30?
1. No and no, since they are burned out.
2. Blowdown Hydraulic.
-
#52
by
PahTo
on 24 May, 2013 20:14
-
Thanks Jim. Time to research blowdown hydraulic...
-
#53
by
Chris Bergin
on 24 May, 2013 20:42
-
ULA:
Everything is progressing toward a launch at 8:27 p.m. of the WGS-5 satellite for the U.S. Air Force.
Fueling is underway.
-
#54
by
Nick L.
on 24 May, 2013 21:06
-
Thanks Jim. Time to research blowdown hydraulic...
In a blowdown hydraulic system the hydraulic fluid is pressurized by a fixed amount of pressurized gas, as opposed to by a hydraulic pump. A consequence of this is that you have to dump the hydraulic fluid overboard as you move the actuators, and so if you move the nozzles a lot more than you anticipated you can run out of hydraulic fluid (this is what happened to the first Delta III).
Edit: A little OT, but here's a document that compares the Japanese H-IIA to its predecessor, the H-II, and talks about the cost and reliability improvements. Page 48 discusses the change from a pump-driven closed system to a blowdown system for the first stage TVC:
https://www.mhi.co.jp/technology/review/pdf/e392/e392043.pdf
-
#55
by
PahTo
on 24 May, 2013 21:13
-
Thanks Nick L. It seems such a system is less complex, has less mass and less cost than a "traditional" hydraulic system of pump-fed actuators. Considering the RS-68 has TVC, I imagine running out of fluid is less of a concern.
-
#56
by
jacqmans
on 24 May, 2013 22:19
-
-
#57
by
Chris Bergin
on 24 May, 2013 22:31
-
ULA:
T-2 Hours.
The team is not currently working any technical issues that would prohibit an on-time launch at 8:27 p.m. of the WGS-5 satellite for the U.S. Air Force.
-
#58
by
Rocket Science
on 24 May, 2013 23:42
-
T-minus 4 minutes and holding. The countdown has entered the planned 45-minute hold.
-
#59
by
Prober
on 24 May, 2013 23:45
-
