-
#420
by
Lar
on 26 May, 2014 16:03
-
Appears to be behind a paywall but looks pretty awesome from the abstract.
-
#421
by
Prober
on 26 May, 2014 17:25
-
they did test it
-
#422
by
jongoff
on 26 May, 2014 17:51
-
Appears to be behind a paywall but looks pretty awesome from the abstract.
Yeah, I haven't had a chance to look to see if there's a free version somewhere.
~Jon
-
#423
by
savuporo
on 26 May, 2014 18:03
-
Appears to be behind a paywall but looks pretty awesome from the abstract.
Yeah, I haven't had a chance to look to see if there's a free version somewhere.
~Jon
On chinese websites, yes. I posted a presentation with excerpts somewhere here. I believe posting the full paper would be AIAA copyright violation.
-
#424
by
jongoff
on 26 May, 2014 18:09
-
Appears to be behind a paywall but looks pretty awesome from the abstract.
Yeah, I haven't had a chance to look to see if there's a free version somewhere.
~Jon
On chinese websites, yes. I posted a presentation with excerpts somewhere here. I believe posting the full paper would be AIAA copyright violation.
Yeah, after looking around that seems to be the case. I've seen cases where one of the coauthors was able to post an AIAA paper for free (like many of the papers on the ULA site), but it looks like people will need to pay to read in this case.
~Jon
-
#425
by
jongoff
on 26 May, 2014 18:09
-
they did test it
Can you provide a citation? I'd like to verify that the test actually happened, and if it was successful.
~Jon
-
#426
by
quanthasaquality
on 26 May, 2014 18:48
-
Is staged combustion worth the hassle for a first stage engine? SpaceX upped its sea level Merlin ISP from ~255 to 282 by increasing the chamber pressure to ~100 bar. Maybe just grow the rs-27a some, and increase its chamber pressure from 50 bar, to 120 bar to get a ~200 ton rocket engine? heck, give it some atlas v srbs, and we'll have a real delta iv.
-
#427
by
Prober
on 26 May, 2014 19:17
-
-
#428
by
savuporo
on 26 May, 2014 21:01
-
There's a huge difference between J-2X, which was a new engine development based loosely off of an engine that was out of production for decades, and an RD-180 project that would be derived from an existing, in-production engine. ..
Interesting tidbit by the way. RS-84 program manager John Vilja at Rocketdyne ( see IAC-03-V.5.03 ) was also a J2-X program manager until 2011
-
#429
by
Lobo
on 27 May, 2014 19:31
-
Is staged combustion worth the hassle for a first stage engine? SpaceX upped its sea level Merlin ISP from ~255 to 282 by increasing the chamber pressure to ~100 bar. Maybe just grow the rs-27a some, and increase its chamber pressure from 50 bar, to 120 bar to get a ~200 ton rocket engine? heck, give it some atlas v srbs, and we'll have a real delta iv.
That's a possibility. Keep the Atlas Core the same, develop an RS-27A-like "sustainer" smaller engine that's GG keorlox and would drop in for the RD-180. And then just assume SRB's would be used more often to make up the dV differnet between the RD-180 and the GG-kerolox sustainer engine, as the propellant volume would remain constant as the Atlas core wouldn't change. Atlas 551 would not have the capability it has now, but each lighter config could probably be replicated. An Atlas 531 or 541 would add an SRB to make up the dV.
Atlas V-411 or 421 would fly more often in place of the 401 version. Not sure what the cost per SRB is, but if that GG sustainer engine could be made equivalently more cheaply than the domestics RD-180, the price could be a wash. And development might be faster and cheaper.
However, no such engine exists. There's not even a similar engine ever developed. You'd need something in probably the 600-700klbs of thrust range, augmented by 1-2 Atlas SRB's to replicate the RD-180 I think. That'd be a brand new engine from scratch, where a domestic RD-180 would be based on an exsiting engine. So I don't know that development of this GG engine would gain anything over domestic RD-180.
-
#430
by
edkyle99
on 27 May, 2014 20:05
-
That's a possibility. Keep the Atlas Core the same, develop an RS-27A-like "sustainer" smaller engine that's GG keorlox and would drop in for the RD-180. And then just assume SRB's would be used more often to make up the dV differnet between the RD-180 and the GG-kerolox sustainer engine, as the propellant volume would remain constant as the Atlas core wouldn't change.
Propellant volume might remain the same, but substantially less propellant could be loaded because the GG engine would have a smaller LOX to kerosene mixture ratio. The kerosene tank would have to be left partly empty, which is a big performance hit. A fix would be to resize the tanks, but while at it might as well stretch them too to make up the ISP difference, which would require more thrust. You would end up with something roughly like a Falcon 9 v1.1 first stage, though maybe with only seven or eight Merlins.
Or two of these.
- Ed Kyle
-
#431
by
Lobo
on 28 May, 2014 00:29
-
That's a possibility. Keep the Atlas Core the same, develop an RS-27A-like "sustainer" smaller engine that's GG keorlox and would drop in for the RD-180. And then just assume SRB's would be used more often to make up the dV differnet between the RD-180 and the GG-kerolox sustainer engine, as the propellant volume would remain constant as the Atlas core wouldn't change.
Propellant volume might remain the same, but substantially less propellant could be loaded because the GG engine would have a smaller LOX to kerosene mixture ratio. The kerosene tank would have to be left partly empty, which is a big performance hit. A fix would be to resize the tanks, but while at it might as well stretch them too to make up the ISP difference, which would require more thrust. You would end up with something roughly like a Falcon 9 v1.1 first stage, though maybe with only seven or eight Merlins.
Or two of these.
- Ed Kyle
Ahhh...good point. Thanks for that Ed. Yea, that would pretty much discount any thought of this.
Any replacement for RD-180 would need a similar mixture ratio to avoid needing to change the actual core beyond the MPS itself.
Might as well just put an F-1B on it, use the D4 5m tank tooling and 5m DCSS, put a MARC-60 on it rather than the RL-10B, Call it an "Atlas V Phase 2/B" and be done with it. :-)
(ULA can only operate Atlas V and derivatives, so I don't think they could call something an "Atlas 6" or anything. It would need to be called an "Atlas V (insert derivative designation here) I think)
-
#432
by
savuporo
on 28 May, 2014 00:37
-
ULA can only operate Atlas V and derivatives...
Where does that come from, by the way ? IIRC the deal they signed in 2005 left the door open for future ELV and RLV developments by ULA, and the text of agreement should be available on sec.gov
-
#433
by
Jim
on 28 May, 2014 00:41
-
Where does that come from, by the way ? IIRC the deal they signed in 2005 left the door open for future ELV and RLV developments by ULA, and the text of agreement should be available on sec.gov
That is the deal between Boeing and LM
-
#434
by
savuporo
on 28 May, 2014 00:46
-
That is the deal between Boeing and LM
Nothing in the Master Agreement for ULA says they cannot develop new vehicles though. And FTC amended approval did not say anything about new vehicle developments at all - there were only equal payload treatment provisions and sensitive information safeguard provisions.
-
#435
by
Jim
on 28 May, 2014 09:06
-
That is the deal between Boeing and LM
Nothing in the Master Agreement for ULA says they cannot develop new vehicles though. And FTC amended approval did not say anything about new vehicle developments at all - there were only equal payload treatment provisions and sensitive information safeguard provisions.
Section 5.13 Non-Competition Agreement.
-
#436
by
savuporo
on 28 May, 2014 15:00
-
That is the deal between Boeing and LM
Nothing in the Master Agreement for ULA says they cannot develop new vehicles though. And FTC amended approval did not say anything about new vehicle developments at all - there were only equal payload treatment provisions and sensitive information safeguard provisions.
Section 5.13 Non-Competition Agreement.
Umm. That section is expired by now - the "design and development" section part valid only for 5 years, and operating part for 7.5. The deal closed in 2006 so we are well past the expiry date.
In addition, i am not a lawyer, but i did NOT read this as an all out ban of launch vehicle development - just the USG market part.
-
#437
by
Jim
on 28 May, 2014 15:18
-
That is the deal between Boeing and LM
Nothing in the Master Agreement for ULA says they cannot develop new vehicles though. And FTC amended approval did not say anything about new vehicle developments at all - there were only equal payload treatment provisions and sensitive information safeguard provisions.
Section 5.13 Non-Competition Agreement.
Umm. That section is expired by now - the "design and development" section part valid only for 5 years, and operating part for 7.5. The deal closed in 2006 so we are well past the expiry date.
In addition, i am not a lawyer, but i did NOT read this as an all out ban of launch vehicle development - just the USG market part.
Still Boeing and LM are not going to let ULA compete in a market where one or both could do it alone.
-
#438
by
savuporo
on 28 May, 2014 15:21
-
That is the deal between Boeing and LM
Nothing in the Master Agreement for ULA says they cannot develop new vehicles though. And FTC amended approval did not say anything about new vehicle developments at all - there were only equal payload treatment provisions and sensitive information safeguard provisions.
Section 5.13 Non-Competition Agreement.
Umm. That section is expired by now - the "design and development" section part valid only for 5 years, and operating part for 7.5. The deal closed in 2006 so we are well past the expiry date.
In addition, i am not a lawyer, but i did NOT read this as an all out ban of launch vehicle development - just the USG market part.
Still Boeing and LM are not going to let ULA compete in a market where one or both could do it alone.
Are you saying that there is a separate agreement from what was approved by FTC? They might be interested to know, because they approved the joint venture based on the provisions in the master apprement, and filed complaints and inputs from DoD ?
-
#439
by
Jim
on 28 May, 2014 15:44
-
Are you saying that there is a separate agreement from what was approved by FTC? They might be interested to know, because they approved the joint venture based on the provisions in the master apprement, and filed complaints and inputs from DoD ?
You have Boeing and LM personnel as part of the board of directors, why would they let ULA do something, when they could do alone?