Author Topic: DARPA Experimental Spaceplane 1 (XS-1) Program  (Read 208254 times)

Offline Robotbeat

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #40 on: 09/16/2013 08:51 AM »
Don't forget Blue Origin, who has more experience with fast turnaround than SpaceX does and is working on a hydrolox VTVL first stage.
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Offline ChrisWilson68

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #41 on: 09/16/2013 09:18 AM »
Sure, Blue Origin could also be getting to that point.  But it's a lot harder to tell with them since they keep everything so quiet and don't have or want (at this point) any customers.  Has Blue Origin already built a vehicle that they think can reach Mach 10 and then land again?  I have no idea.

Offline a_langwich

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #42 on: 09/16/2013 09:24 AM »
Rascal had pretty good program requirements as well.

The question is how DARPA avoids the X-33/RASCAL  trap of picking a winner who can't actually meet the requirements.

DARPA can avoid that by setting requirements more conservatively, but then they wouldn't be DARPA.  It's absolutely necessary and expected that they take big risks.  Problems are expected, failures aren't completely surprising.  The object is to get enough high-payout successes to offset a fair number of failures made cheaper by careful monitoring and early cutoff.

A core part of RASCAL was as Jon Goff described:  MIPCC on the aircraft first stage, which pre-injects water and LOX in front of a standard F100-PW-200 engine.  Staging occurred at a Mach 3-ish pullup maneuver.  I don't think MIPCC could stretch much further than that.  Mach 10 is right out.

A custom-designed, fairly large Mach 3 aircraft is no small task.  I'm not at all surprised it was looking like it would take more than $100 million, which was more than DARPA wanted to spend.  (I'm saying it wasn't the contractor's fault.)  All the traditional aerospace companies who have experience in Mach 2+ aircraft would laugh at that price.

Back on the XS-1, I agree with Jon, Mach 10 is very ambitious.  For a rocket, that's going to be really high and fast and far downrange to recover.  For an aircraft...well, there's been only one aircraft ever to do that, right?  If you count Mach 9.65 as close enough.  (I'm considering the shuttle to be a rocket passing through that region.)  And the X-43 program cost $230 million according to wikipedia, had no payload, essentially no ability to operate itself outside the hypersonic region, and produced 3 flights, only one of which approached Mach 10.  Hmm, the rocket option is looking better and better.

Offline a_langwich

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #43 on: 09/16/2013 09:29 AM »
Don't forget Blue Origin, who has more experience with fast turnaround than SpaceX does and is working on a hydrolox VTVL first stage.

More experience with fast turnaround?  How many flight tests have they performed?  How many since the vehicle crash?  Have they tested more times than Grasshopper since then?

Offline Robotbeat

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #44 on: 09/16/2013 05:38 PM »
Don't forget Blue Origin, who has more experience with fast turnaround than SpaceX does and is working on a hydrolox VTVL first stage.

More experience with fast turnaround?  How many flight tests have they performed?
A LOT, with several vehicles starting with a jet engine platform, moving to hydrogen peroxide and kerosene/peroxide. They have had several test vehicles. Easily tested far more times than Grasshopper.
Quote
How many since the vehicle crash?  Have they tested more times than Grasshopper since then?
Kind of irrelevant since I was talking about past experience, since they switched over to development of their subscale hydrolox booster (will form basis of the upper stage of their launch vehicle as well as being a path-finder for the first stage). They've had good test-firings of their turbopump-fed hydrolox engine (the first such totally new US hydrolox engine in a long time) and are working on the tank for the subscale booster right now.

It's certainly possible they've done more VTVL testing since then. They're very secretive. But regardless, they have much more VTVL experience than SpaceX does (although SpaceX is operating at large scale).

If you want more info, here's their update thread:
http://forum.nasaspaceflight.com/index.php?topic=10685.700
« Last Edit: 09/16/2013 05:38 PM by Robotbeat »
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Offline Zond

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #45 on: 09/16/2013 05:55 PM »
Don't forget Blue Origin, who has more experience with fast turnaround than SpaceX does and is working on a hydrolox VTVL first stage.

More experience with fast turnaround?  How many flight tests have they performed?
A LOT, with several vehicles starting with a jet engine platform, moving to hydrogen peroxide and kerosene/peroxide. They have had several test vehicles. Easily tested far more times than Grasshopper.
There's no evidence Blue Origin has made more then 7 flights (1 by Charon, 3 by Godddard, 2 by PM2 and one pad escape test). Wikipedia lists them all: http://en.wikipedia.org/wiki/Blue_Origin.
That's the same as the amount of flights Grasshopper has made.

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #46 on: 09/16/2013 10:01 PM »
Remember, this is DARPA that we're talking about.

     Someone in the military must think that the fast turn around maybe needed and is assuming that payloads for such a quick succession of launches would be available. Or more precisely, be required.   I don't know of any mass production line of satillites going on, but it doesn't mean that they couldn't have other payloads in mind.

Well, knowing Jess Sponable's past history, here's my hunch. By requiring 10 flights in 10 days of the first stage, you pretty much guarantee that the per flight maintenance for that stage has to be low. You might be able to get away with doing two flights back to back by scrimping on needed maintenance, but if you're talking 10 flights back to back to back, that's hard to do unless the actually maintenance per flight is really low--which is a real key to keeping an RLV's cost down.

Right now, when people look at "RLVs" like shuttle, they see something that takes weeks or months to turn around, and that would be hard pressed to get 50flts/yr on an airframe even if there were payloads for it. If you have something that can really do 10 flights in 10 days, that's pushing a lot closer to the sub one week normal operations turnaround that is needed to get the flight rates for the economics to really do interesting things.
~Jon

It's good to hear that Sponable will be in charge of this, but another obvious key question is how big is the budget?

IIRC DC-X could hit M3 at a price of $60m, as can SS2, but at considerably higher cost I know, bigger payload, certified for paying passengers etc, but I think there is a point that wings do need more design work up front.

So doable with rockets at a "relatively" low price.

Air breathing I think will need to put a lot more cash on the table unless they can get something close to a flyable airframe, that already exists from somewhere.

Where does one get an M10 winged airframe (that's 1.5x the top sped of an X15) in a hurry?  I've no idea.  :(

OTOH if this is a launcher then a design that can handle M10 for minutes should be good enough to get the the job done, and that opens various options (different people will have their preferences). But operability and maintainability....

If Sponable is playing X plane rules "best simple" wins, however there is a wrinkle that they might consider.

The RENE concept put a divergent duct around a rocket engine. This gave a 55% boost in thrust roughly in the M0-M2 range using a fixed duct geometry that needed no more than 3x the mass flow of the core rocket (earlier concepts worked around 20x that). There is also the idea of "thermal choke" to give a sort of "virtual nozzle" effect that can be controlled by fuel flow.

That (in principal) gives a simple (fixed element) low area (hence low mass) inlet design that gives a substantial thrust boost just when the vehicle will be heaviest. If all the new stuff weighs < 50% of the engine dry mass you're ahead of the game. More risky but high payoff.

BTW let me ask a really dumb question.

M10 Horizontal or M10 vertical?

Because it does not say on the slides and you know what they say about "assuming" things  :)

A truly open competition should produce some interesting submissions. I just hope they focus on the goal, rather than the technology.
« Last Edit: 09/16/2013 10:15 PM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline jongoff

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #47 on: 09/18/2013 06:32 AM »
New info:
https://www.fbo.gov/utils/view?id=e66b00991b0418e815627bd9e7688aa3

There will be a proposer's day on the 7th and 8th of October in DC (need to register in advance if you want to attend).

Also, apparently the Mach10 number is not the normal staging velocity, but a "we want to reach this speed with the stage at least once".  I don't know if they require you to get to Mach 10 and reenter without doing retropropulsion, or if they would be ok with basically a stunt demonstrating that capability. But by not having the actual staging velocity at Mach 10, this seems to be a lot more likely to get a broad range of ideas proposed. Hopefully this results in flight hardware.

More thoughts tomorrow maybe.

~Jon

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #48 on: 09/18/2013 08:08 AM »
New info:
https://www.fbo.gov/utils/view?id=e66b00991b0418e815627bd9e7688aa3

There will be a proposer's day on the 7th and 8th of October in DC (need to register in advance if you want to attend).
OK the document seems to make things a bit clearer.

I guess (and this will sound quite stupid) it depends what you mean by "aircraft."

The common understanding is a crewed powered HTHL winged vehicle taking off from a runway and returning to it. But as people here know the full range of vehicles that term could cover is much wider.

The trouble is that (common definition) pretty much drops out all the cheapest options IE rocket based vertical launch. OTOH later it merely asks for "aircraft like" operations, so maybe they are back in?

That single test to M10 suggests that they would accept a vehicle that can do 10 flights in 10 days with a "flight skin" and a single test of a full M10 rated TPS on top of it as the final flight.

One observation I'll make. The X15 was designed to investigate prolonged exposure to hypersonic flight. If the test programme vehicle just has to "kiss" the M10 limit what is effectively an X15 structure might be much closer to viable for this than it's maximum test speed (M6.15 IIRC?) would suggest.

Note I think you could use the structures technology. The actual design is just too small to pack a 2nd stage able to carry 3-5Klb to orbit, even if you junk the safety and life support and run it as a drone. Note the size,thrust and cost requirements might be small enough to make the use of Xcor piston pumps worthwhile and a NASA/Aerojet team have succeeded in producing a pressure fed wit Isp of 335sec with NTO/N2H4.

http://esto.nasa.gov/conferences/nstc2007/papers/Miller_Scott_D11P2_NSTC-07-0039.pdf

But with NTO at $12/lb and N2H5 at c$60/lb that sounds like you're turnaround budget will be hit hard.
« Last Edit: 09/18/2013 08:11 AM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline R7

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #49 on: 09/18/2013 08:54 AM »
Quote
The objective of the XS-1 program is to design, build, and demonstrate a reusable Mach 10 aircraft

Whoops, that's a 11 digit budget already right there. What they are asking is hypersonic B-1 for $5M/flight (US included). Affordable minisat launch system insisted to be done the most expensive way, does not compute. I reckon some studies will be done to leech R&D money and that's it.
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Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #50 on: 09/18/2013 10:45 AM »
Quote
The objective of the XS-1 program is to design, build, and demonstrate a reusable Mach 10 aircraft

Whoops, that's a 11 digit budget already right there. What they are asking is hypersonic B-1 for $5M/flight (US included). Affordable minisat launch system insisted to be done the most expensive way, does not compute. I reckon some studies will be done to leech R&D money and that's it.
Hence my question about the budget, which IIRC on any individual DARPA project is quite small.

I'm reminded of the guy LockMart put in charge of the X33 saying he'd done 38 hypersonic projects but he could say anything about any of them. My question would have been how many of them went to actual flight hardware?
Because on this basis he could be looking at his 39th.  :(  :(

DARPA might be called the almost Impossible Mission Force  :) but this is really pushing things.

OTOH It is not a cruise mission. Something that just has to reach M10 for a few minutes (seconds?) to do it could be a very different beast than what most people would call an aircraft.

Ablatives, transpiration and heat pipe cooling are all in the mix, but just getting up to M10 suggests you're not just going to want to limit your time there, you're going to want to get to M10 (and back) ASAP.

But it's not looking good.  :(






"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline R7

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #51 on: 09/18/2013 11:30 AM »
OTOH It is not a cruise mission. Something that just has to reach M10 for a few minutes (seconds?) to do it could be a very different beast than what most people would call an aircraft.

Yup, and your previous question whether it's M10 horizontal or vertical isn't dumb at all. Related question is M10 at what altitude? Mid-stratosphere with implications of airbreathing engines or mesosphere where rocket engines are given?

[tinfoil hat on]

It's an obfuscated hypersonic bomber research program.

[tinfoil hat off]

There's no real strategic need for hypersonic bomber.
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Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #52 on: 09/18/2013 12:33 PM »
OTOH It is not a cruise mission. Something that just has to reach M10 for a few minutes (seconds?) to do it could be a very different beast than what most people would call an aircraft.

Yup, and your previous question whether it's M10 horizontal or vertical isn't dumb at all. Related question is M10 at what altitude? Mid-stratosphere with implications of airbreathing engines or mesosphere where rocket engines are given?
I think a lot of questions will get (or need to get) answered on the industry open day. Leaving the staging open would be very much in keeping with the X plane ethos (Performance based, not prescriptive on methods). The slides were vague on the V Vs H matter and it does make a serious difference on your 2nd stage (which is part of the package).

Quote

[tinfoil hat on]

It's an obfuscated hypersonic bomber research program.

[tinfoil hat off]

There's no real strategic need for hypersonic bomber.
I think various bits of the US military would still like a high speed strike weapon that is not an ICBM, for which this could serve as the launch platform. But they would not get the weapon at typical DARPA budgets, so it's already developed, or they are hoping it can be.

The other item that will stop people spec'ing stuff out till the open day is they've given a mass but no idea of payload density or form factor.  4000lb is roughly 95 litres at the density of Tungsten (IE bunker buster penetrator) but IRL nearer 2m^3 for a payload with the density of water. Not even a diameter. 32" (like the width, IIRC,  of say an F106 supersonic bomb bay)? 50" (like a Pegasus rocket)? Sized for the EELV secondary adaptor (1m cubes, but satellites that have used all 6 slots and the adaptor structure as the satellite)?

It's reasonable to assume (with the usual caveat about "assuming" anything  :) ) that they would want it compatible with something, in case the project fails and they'd like it (their notional payload) to ride on something else.

BTW I think a pulse detonation engine could go to M10 at a not entirely silly budget (flew around 2006 and I think the AFRL learned a lot, sub or low super sonic manned aircraft), but then so could a rocket, but anything close to a conventional system with a turbine? That will be "challenging."  :)

« Last Edit: 09/18/2013 12:35 PM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Robotbeat

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #53 on: 09/18/2013 03:53 PM »
Quote
The objective of the XS-1 program is to design, build, and demonstrate a reusable Mach 10 aircraft

Whoops, that's a 11 digit budget already right there. What they are asking is hypersonic B-1 for $5M/flight (US included). Affordable minisat launch system insisted to be done the most expensive way, does not compute. I reckon some studies will be done to leech R&D money and that's it.
Can be far, far smaller than a B-1. And they are using "aircraft" liberally. Doesn't actually have to have wings.
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Offline R7

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #54 on: 09/19/2013 08:35 AM »
Can be far, far smaller than a B-1.

Imagery and text shows wings, HTHL, hypersonic flight (sounds like involves lift) etc. if they keep insisting on that it's hard to see the spaceplane far, far smaller. We are talking ~40klbs payload here.

If Grasshopper approach is OK then ... just wait for the F9R.
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Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #55 on: 09/19/2013 10:11 PM »
Can be far, far smaller than a B-1.
Imagery and text shows wings, HTHL, hypersonic flight (sounds like involves lift) etc. if they keep insisting on that it's hard to see the spaceplane far, far smaller. We are talking ~40klbs payload here.
If this vehicle has to be able to carry 4000lb and gives the payload M10 horizontal velocity that leaves about M13 to go. That improves the mass fraction quite a lot. An Isp of 335secs (NASA storable propellant programme for upper stage engines NTO oxidzer) gives a 26% structural fraction. Historically the payload has been a small fraction of that but the SIC 1st stage weighed roughly 55 [edit that should be 5% ] of it's propellant with the rest of the Saturn V stack sitting on top of it. with 12% of 26% for payload that would would leave 13% for structure, which would be pretty good. That would put the whole 2nd stage around 32Klb if that level of propellant can supply enough impulse to get to orbit.

I'll note that the XB70 payload was around 50Klb, but with very long range. Obviously reducing the payload and the fuel load substantially, cutting the range by several 1000 nm, while only requiring that top speed for a few minutes (seconds?) and either reducing (The original XB70 has a crew of 4) or eliminating the crew entirely should cut down the size quite a bit but that would still leave a very big plane  :(
« Last Edit: 09/20/2013 09:21 AM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline a_langwich

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #56 on: 09/20/2013 01:09 AM »
I think X-15 or XB70 style winged, in-atmosphere Mach 10, with a payload large enough to support a second-stage and payload, is orders of magnitude more budget and risk.  Zero chance it could be executed in their budget range.

And DARPA of all organizations should be acutely aware of that.  They've tried X-43, X-51, Falcon, etc--what were you saying john smith about a project manager with 38 hypersonic projects under his belt?  Yep.  And not a one was a roaring success, at least that we know about (and by now we certainly would have known).  Most were successes in the sense that a flight test failure is a success, by teaching you things to avoid and ways the world is more complicated than you expected. 

The more I think about it, the more only a Grasshopper 2+ / F9R approach seems likely to fit in the budget.  Mach 10 way out past atmospheric heating concerns, possibly on a non-standard (maybe even suborbital) trajectory just to hit M10, one orbital flight, and a bunch of small hops for the other 10 days.  Sized as big as a F9R first stage, you could easily reserve enough performance from the payload to support more options on the return.  Or look into slightly less performance, more maintainability or durability engine options.

Thing is, I doubt you could actually develop F9R/Grasshopper from scratch on the DARPA budget or schedule, and meeting their operating/turnaround budget would still be extremely challenging.  If you can't develop (and I don't mean develop the technology, I mean develop the industrial ability to construct, test, and operate that size and type of machinery) for that amount of money, then SpaceX and BlueOrigin are likely to be the only contenders, and I suspect I'm being generous by including Blue Origin.  If they aren't interested, then I'd be inclined to agree with R7.  They'll do some paper studies saying it would be perfectly feasible at a budget higher than DARPA is willing to spend, and take whatever money DARPA does spend, and wrap things up.

I wonder, if you included SpaceLaunch's carrier and first stage as your "first stage," and you recovered the first (rocket) stage, if that would meet their requirements?

It will be interesting to watch.  Sometimes ambitious requirements turn out to be not just a stretch, but wishing for ponies.

Offline ChrisWilson68

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #57 on: 09/20/2013 01:22 AM »
The more I think about it, the more only a Grasshopper 2+ / F9R approach seems likely to fit in the budget.  Mach 10 way out past atmospheric heating concerns [...]

Thing is, I doubt you could actually develop F9R/Grasshopper from scratch on the DARPA budget or schedule

Yeah, the easiest way to do it, by far, seems like the F9R/GH2 approach.  But then the question is, with SpaceX already so far along that road, why bother duplicating it starting from scratch?

Offline Robotbeat

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #58 on: 09/20/2013 02:43 AM »
The more I think about it, the more only a Grasshopper 2+ / F9R approach seems likely to fit in the budget.  Mach 10 way out past atmospheric heating concerns [...]

Thing is, I doubt you could actually develop F9R/Grasshopper from scratch on the DARPA budget or schedule

Yeah, the easiest way to do it, by far, seems like the F9R/GH2 approach. ...
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Offline darkbluenine

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #59 on: 09/20/2013 02:47 AM »
The more I think about it, the more only a Grasshopper 2+ / F9R approach seems likely to fit in the budget. 

I wonder what it would cost to resurrect X-33 and finish it with some metal tanks?  It was supposed to hit Mach 13, and could maybe take the mass hit from less advanced propellant tanks and still hit Mach 10.  NASA put $922M and L-M put $357M into the vehicle.  The work remaining might fit a DARPA budget.

X-34 is an interesting data point.  IT was supposed to be a Mach 8 vehicle, and $112M was spent on the project.  Although it was too small for the stated payload, something "X-34-ish" could fit a DARPA budget.

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