Author Topic: AJAX Launcher  (Read 396563 times)

Offline Downix

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AJAX Launcher
« on: 07/14/2010 10:28 PM »
Someone suggested that we put the current configuration in the first entry, so here goes:

AJAX is a means of achieving the goals of the Congressionally mandated Space Launch System while reducing overhead costs by sharing resources with other United States launch systems.  By studying the various Shuttle components, it was determined the optimal configuration would be to replace the existing pair of segmented solid rocket boosters with 2 pairs of liquid rocket boosters.  For cost, political and performance purposes, AJAX chose the ULA Atlas Common Core Booster (CCB).

The AJAX configuration is centered around a reduced size core module, based on the Space Shuttle's External Tank.  To enable this to operate, AJAX utilizes between 2 and 8 CCBs, to optimize it's lift to the mission profile.  Because the CCBs have less sea level thrust than the SRBs, the ET's fuel load needs to be adjusted.  However as the CCBs have a longer burn duration than the SRBs, less fuel is needed by the core to reach orbit.  By shrinking the ET by approximately 20%, we get comparable orbital performance, while increasing the thrust/weight ratio for better safety margin.  In addition, unlike SRBs, CCBs are fueled at the pad which means you can use more of them to achieve higher lift performance.

And to further improve the overhead, AJAX would share components with the existing EELV's beyond the CCB as well.  Instead of a large, expensive customized upper stage, AJAX would utilize ULA's existing upper stages.  Part of the program would be to fund the development of ULA's proposed ACES upper stage, giving a unified upper stage across three vehicles.  In addition, by the use of the CCB, AJAX would also enable the development, and operation, of the Atlas V HLV for crew lift from LC-39.

The issue with most SLS systems is the number of unique SLS-only components.  AJAX's goal is to eliminate as many of those as practicable.  Michoud would be shared with the Orion space capsule, LC-39 with manned Atlas V Launches, and the boosters would come from Decatur.  In short, it would share overhead, spreading out the cost over multiple agencies, making an AJAX based SLS affordable to operate. 

There is no point to a launcher if you lack the budget to launch it.  AJAX solves this problem by elimination of huge portions of the STS overhead as well as sharing the remaining portions with existing systems.

We are working on a paper giving the full details at this time.  When it is ready, we will be posting it here.

-- original message --
After all discussion, the 4 CCB + 4 SSME w/ full length tank is the concensus.  To get to the right T/W ratio, we have the option of pre-burning the launcher before liftoff, much how the shuttle ignites its engines before liftoff. 

The concept is simple, expanding the concepts behind DIRECT, that is, to better utilize what we have now, in order to build a heavy lift vehicle on todays budget demands.  We will have threads on various elements of this paper rocket, from the MLP, LC-39, and so forth, but this thread is on the lift vehicle itself.

The performance of AJAX is that the design scales from ~70 metric tons up to ~135 metric tons, without the need for an upper stage, by varying the number of Atlas V boosters used.

The general numbers for AJAX to use in Schillings are:

Atlas CCB w/ nosecap (hard numbers):
dry weight: 21,844 kg
Fuel weight: 284,453 kg
Thrust: 4152 kN
isp: 338

Core (rough numbers with margin):
dry weight: 58,000 kg
Fuel weight: 590,000 kg
Thrust: 3-4 engines, throttling between 1402 kN and 2277.2 kN
isp: 453
« Last Edit: 08/10/2011 08:10 PM by Downix »
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Online Robotbeat

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Re: AJAX Launcher
« Reply #1 on: 07/14/2010 10:31 PM »
I'm not sure we reached a consensus vis-a-vis the full-length tank and the pre-burn.
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Offline Downix

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Re: AJAX Launcher
« Reply #2 on: 07/14/2010 10:41 PM »
I'm not sure we reached a consensus vis-a-vis the full-length tank and the pre-burn.
Preburn is only an option, the rocket will take off in any case.  The performance loss from the shrunk tank just does not add up to me.
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Online Robotbeat

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Re: AJAX Launcher
« Reply #3 on: 07/14/2010 10:45 PM »
I'm not sure we reached a consensus vis-a-vis the full-length tank and the pre-burn.
Preburn is only an option, the rocket will take off in any case.  The performance loss from the shrunk tank just does not add up to me.
Does it make sense to lengthen the tank, then?

My point is that there's an optimization step that needs to be done, here. We shouldn't just ignore it. For the CCBs, yes, we are just going to live with whatever they're filled to, but the tank is undergoing such drastic changes that we really should consider what the optimal tank size would be.
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Offline FinalFrontier

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Re: AJAX Launcher
« Reply #4 on: 07/14/2010 10:50 PM »
I'm not sure we reached a consensus vis-a-vis the full-length tank and the pre-burn.

Its not a question of full length OR preburn. Its a question of Full length: preburn, or Full length: CCB LOX float valve to 80%

My vote is a block 1, 2 phasing plan:

Block 1 preburn
Block 2 80% float valve (2 years after block one IOC).
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Offline neilh

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Re: AJAX Launcher
« Reply #5 on: 07/14/2010 10:58 PM »
What are the open questions regarding the launcher that can begin to be addressed in this forum?
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Offline Downix

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Re: AJAX Launcher
« Reply #6 on: 07/14/2010 11:02 PM »
I'm not sure we reached a consensus vis-a-vis the full-length tank and the pre-burn.
Preburn is only an option, the rocket will take off in any case.  The performance loss from the shrunk tank just does not add up to me.
Does it make sense to lengthen the tank, then?

My point is that there's an optimization step that needs to be done, here. We shouldn't just ignore it. For the CCBs, yes, we are just going to live with whatever they're filled to, but the tank is undergoing such drastic changes that we really should consider what the optimal tank size would be.
it's not just that, however.  the shrunk tank was not a major redesign, it was removing a ring out of both the LOX and LH2 tank.  A stretched tank, for comparison, would be adding another ring.

We're still utilizing the parts of the ET, so we do need to keep that in mind.

We can discuss growth options as well in here, set a long distance goal, and figure out the steps to get there.

The other thread had one discussion topic, how would AJAX impact EELV evolution.

It helps to understand Atlas evolution:

Phase I, new upper stage, called ACES

Phase II switch to 5 m core with 2 RD-180.

Phase III new 8.4m core.

AJAX would still be using the ACES for it's upper stage, so this would be funneling the resources for that.

AJAX would also get a huge benefit from the Phase II, as the 5m core w/ two RD-180 would get the better T/W ratio.

So, I see this as being a shot in the arm for EELV evolution as well.  But we're not counting on it, only putting on the table that so we can ponder the Block I, II, III, etc when it comes to it.

Part of the process will be in the use of Atlas as the crew launcher.

Ok, still exhausted from the trip, chew a bit and I'll process more later.  I hope this is not too rambling.
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Offline jml

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Re: AJAX Launcher
« Reply #7 on: 07/14/2010 11:05 PM »
The current Senate draft of the NASA Authorization specifies that NASA shall develop a heavy-lift "Space Launch System" to succeed STS and build upon STS and CxP equipment, infrastructure, and workforce. Interestingly enough, the bill does not actually state that the new SLS vehicle must use solid rocket boosters.

There is this wording that seems to apply only if NASA decides that SRBs are necessary:
The Administrator shall, to the extent practicable, extend or modify existing vehicle development and associated contracts necessary to meet the requirements in paragraph (1), including contracts for ground testing of solid rocket motors, if necessary, to ensure their availability for development of the Space Launch System.

And there's this wording that tells NASA to use stuff they already have:
The Administrator shall, to the extent practicable, utilize existing contracts, investments, workforce, industrial base, and capabilities from the Space Shuttle and former Orion and Ares 1 projects, including Space Shuttle-derived components and Ares 1 components that use existing United States propulsion systems, including liquid fuel engines, external tank or tank-related capability, and solid rocket motor engines, and associated testing facilities, either in being or under construction as of the date of enactment of this Act.

So....does this sound like RD-180 powered CCBs and maybe even wide-body Atlas Phase II CCBs using Delta IV 5m tanking are not prohibited from being used on the "SLS" vehicle?

If that's the case, then NASA can use this ambiguity either as leverage to bring ATK on-board with building 4-seg solids for the new program, or as a way of getting rid of those pesky solids by building AJAX, depending on what is more politically advantageous.

(But do the RD-180s have to be domestically produced?)

Offline neilh

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Re: AJAX Launcher
« Reply #8 on: 07/14/2010 11:32 PM »
We can discuss growth options as well in here, set a long distance goal, and figure out the steps to get there.

The other thread had one discussion topic, how would AJAX impact EELV evolution.

It helps to understand Atlas evolution:

Phase I, new upper stage, called ACES

Phase II switch to 5 m core with 2 RD-180.

Phase III new 8.4m core.

One of the more intriguing future possibilities would be to utilize the mid-air engine recovery that ULA (or was it LM?) proposed for the Atlas. An AJAX based on Phase II or Phase III boosters with mid-air engine recovery for the SSMEs and RD-180s could potentially achieve a pretty incredibly cost/kg, and also involve developments which would help the cost-effectiveness of the Atlas V.

Moving to Phase II or Phase III could also potentially enable evolution to a crazy super-HLV if you increased the ET length, although of course that brings it back to the question of what sort of payloads one would put on it.

Anybody know what mass figures would be like for Phase II/III-based CCBs? I imagine the thrust figures would be more-or-less a multiplier of the RD-180.
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Offline FinalFrontier

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Re: AJAX Launcher
« Reply #9 on: 07/14/2010 11:45 PM »
Mid air recovery might be interesting for future operations. For the next 5-9 years we should focus on bare bones stuff, IMO like DIRECT to keep LV per year costs as low as possible. Mid air recovery (plus the systems needed to make the engines ejectable) would drive up costs.

Keep the baseline simple, introduce new concepts down the road if its prudent. :D

BTW for those who don;t know the Baseline is the AJAX 440. We were pretty settled on the full legnth ET, but the shortened ET is still on the table if everyone wants to continue discussing it. The preferred option is the full length ET, however, ATM.
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Offline Jim

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Re: AJAX Launcher
« Reply #10 on: 07/14/2010 11:59 PM »
Preburning will never be accepted.  There is no such thing as a full length (or "unmodified") ET for this application.  Both ends of the ET will be heavily modified, so make the right size.

There is nothing to gained by keeping it the same length/volume as the shuttle.  Don't touch the CCB's or don't preburn, you will lose support.

Neither preburn nor partially filling of tanks are acceptable engineering solutions.
« Last Edit: 07/15/2010 12:01 AM by Jim »

Offline martin hegedus

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Re: AJAX Launcher
« Reply #11 on: 07/15/2010 04:07 AM »
A basic question.  From what I understand from previous posts is that the CCB will need to be human rated.  To do that Chuck said that a sensor package will need to be added to the RD180.  Will the engine need to be modified for the addition of this package?  Does this constitute a change to the CCB?  Will any other sensors need to be added to the CCB for human rating, such as in the tank?  Will any other changes need to be made to the CCB for human certification?

Offline FinalFrontier

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Re: AJAX Launcher
« Reply #12 on: 07/15/2010 04:10 AM »
Preburning will never be accepted.  There is no such thing as a full length (or "unmodified") ET for this application.  Both ends of the ET will be heavily modified, so make the right size.

There is nothing to gained by keeping it the same length/volume as the shuttle.  Don't touch the CCB's or don't preburn, you will lose support.

Neither preburn nor partially filling of tanks are acceptable engineering solutions.
And while changing the shape of a LOX tank and adding: 1. An extra layer of grid panels in specific positions and 2. thrust structure, do consitute changes to the overall preformance, doing all that and changing length constitute even more issues.

Point being there are problems with both solutions, the trick is finding the solution that:

Is cost effective

Is the simplest to implent

Has the least amount of preformance losses


Is the least politcally impactful (when discussing CCBs).


Perhaps core length change is the way to do this, perhaps that leads to the Ares road.........Same is true of CCB float valve or preburn.
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Offline martin hegedus

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Re: AJAX Launcher
« Reply #13 on: 07/15/2010 04:26 AM »
I hope someone can clarify this for me.  The loads and the load paths for the ET have completely changed, even when compared to Jupiter.  So I assume the ET/core is being completely redesigned and tested from top to bottom.  OK, there may be a few parts reused from the Shuttle ET.  But I guess I don't understand why changing the length is an issue unless it effects the CCBs.

Offline FinalFrontier

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Re: AJAX Launcher
« Reply #14 on: 07/15/2010 04:29 AM »
I hope someone can clarify this for me.  The loads and the load paths for the ET have completely changed, even when compared to Jupiter.  So I assume the ET/core is being completely redesigned and tested from top to bottom.  OK, there may be a few parts reused from the Shuttle ET.  But I guess I don't understand why changing the length is an issue unless it effects the CCBs.


1. Its not a totall redesign. There are modifications but its not a brand new ET (like for example larger diameter).

2. In theory length changes aren't a huge deal, but you have to watch out for preformance hits, fuel consumption issues (don't forget that 4th SSME), and ESPECIALLY changes to the load path ABOVE AND BEYOND the changes expected when going from the STS ET to the AJAX core.

There are already load path changes, why add more?
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Offline martin hegedus

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Re: AJAX Launcher
« Reply #15 on: 07/15/2010 04:54 AM »
I hope someone can clarify this for me.  The loads and the load paths for the ET have completely changed, even when compared to Jupiter.  So I assume the ET/core is being completely redesigned and tested from top to bottom.  OK, there may be a few parts reused from the Shuttle ET.  But I guess I don't understand why changing the length is an issue unless it effects the CCBs.


1. Its not a totall redesign. There are modifications but its not a brand new ET (like for example larger diameter).

2. In theory length changes aren't a huge deal, but you have to watch out for preformance hits, fuel consumption issues (don't forget that 4th SSME), and ESPECIALLY changes to the load path ABOVE AND BEYOND the changes expected when going from the STS ET to the AJAX core.

There are already load path changes, why add more?

No disrespect, but I guess I disagree, in the sense that the design should be approached as a total redesign, even if the radius and some parts are reused.  In my personal experience, it is under appreciating (for lack of better words) changes which cause failures.  So I'm not sure how much time and money not changing the length of the core would save.

Offline jml

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Re: AJAX Launcher
« Reply #16 on: 07/15/2010 06:00 AM »
A basic question.  From what I understand from previous posts is that the CCB will need to be human rated.  To do that Chuck said that a sensor package will need to be added to the RD180.  Will the engine need to be modified for the addition of this package?  Does this constitute a change to the CCB?  Will any other sensors need to be added to the CCB for human rating, such as in the tank?  Will any other changes need to be made to the CCB for human certification?

Adding an Emergency Detection System is a change, but a planned change that ULA intends to add to all CCBs leaving the factory, so that there won't have to be different versions of the CCB for crewed vs unmanned launches.

The details of what's required can be found in these two docs:
http://www.ulalaunch.com/site/docs/publications/AtlasEmergencyDetectionSystem.pdf

http://www.ulalaunch.com/site/docs/publications/HumanRatingAtlasVandDeltaIV.pdf

NASA awarded ULA a $6.7 million Commercial Crew Development (CCDev) Program contract in February to start some basic design/definition work on the EDS for the Atlas and Delta.
http://www.nasa.gov/centers/johnson/pdf/463224main_United%20Launch%20Alliance%20and%20Amendment.pdf

Of course if an Atlas or AJAX is flown with a crewed-capsule, there will be the additional requirement of a LAS...for AJAX and Orion the sensible starting point would be OSC's work on the Ares I LAS.



Offline FinalFrontier

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Re: AJAX Launcher
« Reply #17 on: 07/15/2010 04:05 PM »
Id say its a good day for AJAX. Congress is mandating SDHLV project start in fy2011.

Lets keep going on this design 8)
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Offline martin hegedus

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Re: AJAX Launcher
« Reply #18 on: 07/15/2010 04:20 PM »
A basic question.  From what I understand from previous posts is that the CCB will need to be human rated.  To do that Chuck said that a sensor package will need to be added to the RD180.  Will the engine need to be modified for the addition of this package?  Does this constitute a change to the CCB?  Will any other sensors need to be added to the CCB for human rating, such as in the tank?  Will any other changes need to be made to the CCB for human certification?

Adding an Emergency Detection System is a change, but a planned change that ULA intends to add to all CCBs leaving the factory, so that there won't have to be different versions of the CCB for crewed vs unmanned launches.

The details of what's required can be found in these two docs:
http://www.ulalaunch.com/site/docs/publications/AtlasEmergencyDetectionSystem.pdf

http://www.ulalaunch.com/site/docs/publications/HumanRatingAtlasVandDeltaIV.pdf

NASA awarded ULA a $6.7 million Commercial Crew Development (CCDev) Program contract in February to start some basic design/definition work on the EDS for the Atlas and Delta.
http://www.nasa.gov/centers/johnson/pdf/463224main_United%20Launch%20Alliance%20and%20Amendment.pdf

Of course if an Atlas or AJAX is flown with a crewed-capsule, there will be the additional requirement of a LAS...for AJAX and Orion the sensible starting point would be OSC's work on the Ares I LAS.




Awesome!  Thanks.  I like it when statements are made and backed up with docs or, in the case of presenting derived numbers, a clear description of the process.

Offline Downix

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Re: AJAX Launcher
« Reply #19 on: 07/15/2010 07:19 PM »
I hope someone can clarify this for me.  The loads and the load paths for the ET have completely changed, even when compared to Jupiter.  So I assume the ET/core is being completely redesigned and tested from top to bottom.  OK, there may be a few parts reused from the Shuttle ET.  But I guess I don't understand why changing the length is an issue unless it effects the CCBs.


1. Its not a totall redesign. There are modifications but its not a brand new ET (like for example larger diameter).

2. In theory length changes aren't a huge deal, but you have to watch out for preformance hits, fuel consumption issues (don't forget that 4th SSME), and ESPECIALLY changes to the load path ABOVE AND BEYOND the changes expected when going from the STS ET to the AJAX core.

There are already load path changes, why add more?

No disrespect, but I guess I disagree, in the sense that the design should be approached as a total redesign, even if the radius and some parts are reused.  In my personal experience, it is under appreciating (for lack of better words) changes which cause failures.  So I'm not sure how much time and money not changing the length of the core would save.

The tooling time alone would be on the order of 24 months.  That is 24 months *before* you can start even building a core.  Using the original tools, altho reconfigured, will give you a jumpstart. 

The fewer changes to the tooling means a faster deployment.  We are already making new tools for the base, the reinforcements needed, removal of SRB.  The less new tools we need, the better.

We can change the core length, so long as it is changed with the existing toolset, easily.  Remove a ring/add a ring method.
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