Here's a presentation from July 2013 showing how the dual chamber AJ1E6 would have look like on Atlas."Common engine solution for SLS, Atlas V, & Antares"http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140002714.pdf
They need to get building that thing, pronto!!
Bump:http://aviationweek.com/space/engine-makers-pushing-am-other-technologies-rd-180-replacementAdditive manufacturing reducing time and cost in prototyping, Mondaloy, titanium, copper and other materials being qualified. Could see prototype AR-1 firing in 2.5 years. Lots of challenges yet to be hurdled.
I believe if the AR-1 becomes the engine of choice, and a reality, it will be the end of the Atlas V (unless they continue to fly those with the RD-180). As many have noted often, rockets (and their key components) are not legos...
Quote from: PahTo on 09/14/2014 09:16 pmI believe if the AR-1 becomes the engine of choice, and a reality, it will be the end of the Atlas V (unless they continue to fly those with the RD-180). As many have noted often, rockets (and their key components) are not legos...I agree that the AR-1 and derivatives would most likely be the end of the Atlas V but would it be the beginning of the Atlas VI?
I agree that the AR-1 and derivatives would most likely be the end of the Atlas V but would it be the beginning of the Atlas VI?
Do we know what AR-1 even looks like, performance wise? If it hews pretty close to the NK-33 lineage as is reasonable to suspect, that probably means there's a significant loss of ISP. More thrust means the GLOW can be greater, but that would mean enlarging the first stage to hold more propellant. I don't even know where that nets out performance wise, say it's similar, that still sounds like a lot more than a drop in replacement.This means an Atlas V v1.1, essentially.
Might be OT but... Would it make sense to develop not only common engines for Atlas Z and SLS LRBs, but also use the same first stage? I.E. that the first stage of Atlas Z would be the SLS LRB. Or would the requirements be so different, that it is cheaper to develop, build and operate two different desings?
Would it make sense to develop not only common engines for Atlas Z and SLS LRBs, but also use the same first stage?
A re-engined Atlas 5 would just be an Atlas with a modified model number. It could be Atlas 6. It could be Atlas 5b. It might be something else, like Atlas 5000, who knows?. The original (Thor)-Delta rocket series went through at least six different solid booster types, five main and five second stage engine types, and seven upper stage combinations, along with stretches and redesigns of all of the liquid stages, but was always called "Delta"-something. There were Deltas with alpha letter variations followed by Deltas with three and four letter model numbers. Atlas Centaur and Titan both had something similar.
Quote from: ArbitraryConstant on 09/15/2014 06:07 amDo we know what AR-1 even looks like, performance wise? If it hews pretty close to the NK-33 lineage as is reasonable to suspect, that probably means there's a significant loss of ISP. More thrust means the GLOW can be greater, but that would mean enlarging the first stage to hold more propellant. I don't even know where that nets out performance wise, say it's similar, that still sounds like a lot more than a drop in replacement.This means an Atlas V v1.1, essentially.No, I don't think anyone including AR knows what performance would look like. I think they are confident they could get pretty similar performance levels. If 338 Isp vac (RD-180) vs. 331 Isp vac (NK-33) is a "significant loss," then yes, I think it's a foregone conclusion there will be a few Isp difference, up or down.
Quote from: J-V on 09/15/2014 07:44 amWould it make sense to develop not only common engines for Atlas Z and SLS LRBs, but also use the same first stage?Seeking commonality between two applications is always worth considering. In this case, the pair of SLS boosters need to generate between them about six times the thrust of an Atlas first stage. So they couldn't just strap two Atlas first stages onto an SLS core and have any hope of meeting the requirement.It's fascinating to ask, though: what if they strapped six Atlas boosters around the SLS core? That concept has been previously explored under the name "AJAX." The short answer is, "That would work great!" The question, "Why wasn't that approach adopted for SLS?" would require a rather more lengthy answer....
Quote from: sdsds on 09/15/2014 07:57 amIt's fascinating to ask, though: what if they strapped six [AR-1 engined] Atlas boosters around the SLS core? That concept has been previously explored under the name "AJAX." The short answer is, "That would work great!"ISTR that concept included a cut-down core?
It's fascinating to ask, though: what if they strapped six [AR-1 engined] Atlas boosters around the SLS core? That concept has been previously explored under the name "AJAX." The short answer is, "That would work great!"
It also needs six boosters to thrust into the thrust beam, which ISTR involved what was basically an exoskeleton.