Author Topic: 33ft core  (Read 20400 times)

Offline CFE

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Re: 33ft core
« Reply #40 on: 11/24/2007 07:51 PM »
Agreed, Jorge.  It does beg the question of whether a Saturn V-only production line could have made the cut, replacing the Saturn IB with an S-IC + S-IVB vehicle.  It's doubtful, though.

As fas as Jeff Bell goes, I must say that I will agree with at least the first half of a Jeff Bell editorial/screed.  Then he takes a logical turn that's unexpected and extreme, with flimsy evidence to support.  That's the point where he loses me.  But he was totally correct to suggest that "shuttle derived" would evolve into something that has little or no shuttle heritage at all.  We still haven't gotten to his predicted "EELV derived" solution, though.
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Offline luke strawwalker

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Re: 33ft core
« Reply #41 on: 11/27/2007 03:49 AM »
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JIS - 16/11/2007  3:39 AM

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kraisee - 16/11/2007  5:43 AM

Also there are recurring cost implications too.   Every extra J-2X adds about $25m to the cost of each mission.   Add 4 and your per-mission costs would increase by $100m, which given the current LV variable cost will be in the ballpark of $400-450m, is quite an impact.


I agree at this point that 2 J-2X engines on EDS is not a good idea. It would be far better and cheaper to increase J-2X thrust and ISP.

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While lots of trade studies are going on, the only sure thing is that *something* has to change with Ares-I/V if NASA wants to achieve its currently planned missions.   Currently they are well below the line (~20%) performance-wise from closing the performance box using the current configuration of the launchers.   I'm on record for how I'd like to see them change, but I don't know which way they will jump.  

I agree that more payload delivered to the moon the better. I think that for Lunar base construction and supply the key is a payload delivered in one launch. Therefore, I'm glad to see Ares V growing bigger. Hopefully the payload capability will increase as well.
10 m fairing is a very good news for base line LSAM (minimum ascend stage) and LSAM cargo derived from descend stage.

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Only time will tell that, but I am convinced that time is a commodity which we are seriously running out of.
Ross.

The time is tight for J-2X development to get Orion/Ares 1 up and running to support ISS. There is no doubt that Orion/Ares 1 is more than enough for that. There is plenty of time for LSAM and Ares V development.

I never thought I'd agree with JIS on something but I sure do here... upscaling the J-2 to higher thrust/ISP would be a LOT better than slapping a second one on.  Increasing the size of the J-2 to something closer to the SSME's performance (dunno, maybe halfway between the old/currently envisioned J-2 and SSME) would not only help Ares I by giving it more thrust but would save money down the road, because one souped up engine will undoubtedly be cheaper than two dinkyer ones.  I'm sure it would increase the cost of the J-2 in the short term but it would be more than worth it in the long term.  Besides the J-2 is mostly on paper at this point, and it'd be FAR easier and cheaper to choose the right size to build it NOW than later on after it's built, or having to use a second one on every EDS.  JMHO!  OL JR :)
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Offline JIS

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Re: 33ft core
« Reply #42 on: 11/29/2007 09:53 AM »
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luke strawwalker - 27/11/2007  4:49 AM

upscaling the J-2 to higher thrust/ISP would be a LOT better than slapping a second one on.  Increasing the size of the J-2 to something closer to the SSME's performance (dunno, maybe halfway between the old/currently envisioned J-2 and SSME) would not only help Ares I by giving it more thrust but would save money down the road, because one souped up engine will undoubtedly be cheaper than two dinkyer ones.  I'm sure it would increase the cost of the J-2 in the short term but it would be more than worth it in the long term.  Besides the J-2 is mostly on paper at this point, and it'd be FAR easier and cheaper to choose the right size to build it NOW than later on after it's built, or having to use a second one on every EDS.  JMHO!  OL JR :)

Unfortunatelly J-2X has to be of J-2 heritage. The thrust can go up but not by 100% or so. The J-2X basic design is pretty much set now.
The best what they can do right now is to increase ISP a little over 448s.
As Ares V has very powerfull core and the injection orbit is circular the trajectory will be highly lofted. Therefore EDS doesn't need higher thrust.
I also think that they should drop human rating requirement for Ares V especially relax human rating structural requirements for the core.
I'm wondering what will be the payload capability of the new AresV with 10m EDS and higher ISP SRBs (high expansion nozzles).
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Offline William Barton

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Re: 33ft core
« Reply #43 on: 11/29/2007 11:15 AM »
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meiza - 16/11/2007  2:35 PM

It's like saying NASA should have gone to NOVA with eight F-1 engines, and launched one every month, that would have costed so little but the stupid politicians didn't think far enough. Urgh.

With enough exageration, anything can be made to seem absurd. I had a friend back in the 1960s who insisted the thing to do was save up satellites until there were enough to justify a Saturn V payload, and then launch them all at the same time...

Seriously, the point of the notion about keeping the Saturn production line open was result/dollar, not overall cost savings, or fantasies about politicians "seeing the light" and increasing the budgets. We could have had a 1970-1990 "Saturn Era" instead of a 1980-2010 "STS/ISS Era" for about the same money per year, but eventually the Saturn's time would have been over, just as the Shuttle's time is about over. What's worth more, a couple of dozen expeditions to the Moon, or 30 years of relatively unproductive LEO experience?

When you bring in politicians, all you get is what really happened, and guessing what those same politicans would have done if they hadn't done what they did is plainly silly. The only underlying notion is, what could/should we have done with all that money and hardware? The decision would have had to be made by LBJ in 1966, and then whoever won the White House in 1968 would have had to be agreeable. And both of them would have had to have seen the wisdom of bailing out of Vietnam. Which, of course, can only lead to paroxyms of "counterfactuals" arguments. (And, yes, I did publish a story about this 12 stuff years ago.)

Offline William Barton

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Re: 33ft core
« Reply #44 on: 11/29/2007 11:21 AM »
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CFE - 24/11/2007  3:51 PM

Agreed, Jorge.  It does beg the question of whether a Saturn V-only production line could have made the cut, replacing the Saturn IB with an S-IC + S-IVB vehicle.  It's doubtful, though.

As fas as Jeff Bell goes, I must say that I will agree with at least the first half of a Jeff Bell editorial/screed.  Then he takes a logical turn that's unexpected and extreme, with flimsy evidence to support.  That's the point where he loses me.  But he was totally correct to suggest that "shuttle derived" would evolve into something that has little or no shuttle heritage at all.  We still haven't gotten to his predicted "EELV derived" solution, though.

Somewhere on astronautix.com there's an article about a version of the S-IC where by dropping off the four outer engines after 2min and continuing on with the center engine (more or less like the original Atlas), you can put a Shuttle-class payload into LEO for about the same cost as using the Shuttle to do so. That'd replace the Saturn IB as well, I suppose.

The problem with the idea of keeping the Saturn production line(s) open is, all it takes is one decision in one fiscal year to put an end to the whole enterprise.

Offline spacenut

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Re: 33ft core
« Reply #45 on: 11/29/2007 11:37 AM »
There were plans to recover, with parachutes, the Saturn V first stage.  There was also plans to increase the F-1 engine to 2.2 million lbs. of thrust (11 million total), which is the limit of the launch pads today.  The J-2 was to be upgraded from 200,000 lbs of thrust to 275,000 lbs of thrust.  This would have made the Saturn V capable of between 150-175 tons to LEO.  This would have reduced costs/lb to orbit, and with a reusable first stage, costs could have probably been further reduced.  The J-2 hardware was to make a plug nozzle engine for the 3rd stage, so it could have been made reusable, by using it as a heat shield.  The second stage could probably have been made the same and recovered.  The upgrades may have made the Saturn V sustainable.  Also, from what I have read, the cost to launch a Saturn I was about the same as the Saturn V.

Offline ChrisInAStrangeLand

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Re: 33ft core
« Reply #46 on: 11/30/2007 01:08 AM »
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kraisee - 16/11/2007  2:05 PM
I think Ares-I is a long way below the sweet spot, and Ares-V is a long way beyond it.   Which leads me to a conclusion that its somewhere in between.   And we all know where that line of thought leads...

Ross.

Monomania?

Offline Sid454

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Re: 33ft core
« Reply #47 on: 02/12/2008 02:33 AM »
I don't think the change from 27 to 33feet will be an issue for infrastructure but the larger faring could be great for the LSAM and allow it to be a shorter wider design which is better for both stability and safety of the astronauts.

But on cost I have to agree with clongton here flight rate is everything in costs so maybe we shouldn't be trying to make the biggest rocket possible but instead the biggest one that can find a good flight rate and escape the Saturn V's fate if that means two big launches vs one big one and one small one so be it.

My biggest fear with Ares is the program could be canceled before Ares V  flies and then we would be stuck in LEO in a situation a lot worse then the one we are in now as we will not even have the ability to build space stations unless some private group produces a space tug.

Also JPL will get screwed out of an opportunity to have an HLLV to play with and I'd like to see things like an 8M optical space telescope and a Jupiter icy moon orbiter.

Also being able to perform missions with out those time wasting gravity assist flybys would be great.

Offline Jim

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Re: 33ft core
« Reply #48 on: 02/12/2008 02:42 AM »
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Sid454 - 11/2/2008  10:33 PM

I don't think the change from 27 to 33feet will be an issue for infrastructure but the larger faring could be great for the LSAM and allow it to be a shorter wider design which is better for both stability and safety of the astronauts.


again you are clueless.  33 ft has bigissues at the pad

Offline Sid454

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Re: 33ft core
« Reply #49 on: 02/12/2008 02:49 AM »
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spacenut - 29/11/2007  6:37 AM

There were plans to recover, with parachutes, the Saturn V first stage.  There was also plans to increase the F-1 engine to 2.2 million lbs. of thrust (11 million total), which is the limit of the launch pads today.  The J-2 was to be upgraded from 200,000 lbs of thrust to 275,000 lbs of thrust.  This would have made the Saturn V capable of between 150-175 tons to LEO.  This would have reduced costs/lb to orbit, and with a reusable first stage, costs could have probably been further reduced.  The J-2 hardware was to make a plug nozzle engine for the 3rd stage, so it could have been made reusable, by using it as a heat shield.  The second stage could probably have been made the same and recovered.  The upgrades may have made the Saturn V sustainable.  Also, from what I have read, the cost to launch a Saturn I was about the same as the Saturn V.

Yah they had lots of greats plans for Saturn derivatives one of the most interesting was the SASSTO a small Saturn SC-IVB derived vehicle who's payload was a Gemini capsule which would have produced a fast response vehicle for getting into orbit 48 hours from when the order was given.

The SASSTO also was considered as you said as a replacement for the SC-IVB in the Saturn IB and Saturn V

In the IB it would be reusable and would have even increased the vehicle's payload also there were plans on Making the Apollo CM reusable or replacing it with a small space plane for LEO mission.

One of the ironies here is such a reusable stage could even be used with ares I for 18ton or less class vehicles creating what would be NASA's first true RLV.

Offline kraisee

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Re: 33ft core
« Reply #50 on: 02/12/2008 03:45 AM »
Sid,
There are a lot of integration problems they are finding with the 33ft arrangement of Ares-V.   For a start, the SRB's are 6ft wider apart than at present, and even for Shuttle they had to add large deflectors either side of the flame trench to keep the wider footprint firing into a safe zone.   Making the deflectors 6ft wider again is not impossible, but certainly trickier.   Then there is an issue with the SRB ignition shock-waves being in very close proximity to the RS-68's.   The new design for the MLP will not provide a 'wall' between the SRB exhaust and that of the SR-68's, so all the hardware will be exposed to the full environment.

Then there is the issue that the concrete hardstand and flame trench itself have a maximum capability very near to that of the Ares-V's full power.   The teams at KSC are looking at a variety of options such as opening up the sides of the flame trench catacombs to allow exhaust out on three or even four sides, not just two - although this would likely require strengthening of the crawlerway on top of the hardstand to support the great weight.

Which raises the other issue - the pair of 5-seg SRB's, along with the rest of the vehicle, up to 130 tons of payload and the new ML/LUT will together tip the scales far higher than the current Crawlers can handle.   Including the mass of a bigger crawler, the VAB floor, parts of the existing crawlerway and the concrete hardstand are proving to be either at or slightly beyond their design limits already and may well require replacement.

All of this adds up to a seriously extensive amount of change which will be required to support the new 33ft diameter stage configuration on Ares-V.

Ross.
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Offline Jim

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Re: 33ft core
« Reply #51 on: 02/12/2008 04:18 AM »
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kraisee - 11/2/2008  11:45 PM

All of this adds up to a seriously extensive amount of change which will be required to support the new 33ft diameter stage configuration on Ares-V.

Ross.

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Offline mikeh

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Re: 33ft core
« Reply #52 on: 02/12/2008 02:50 PM »
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Sid454 - 11/2/2008  9:33 PM

...maybe trying to make the biggest rocket possible but instead the biggest one that can find a good flight rate and escape the Saturn V's fate ...


The flight rate didn't kill the Saturn V, Nixon and Congress with their lack of funding and canceled programs did the job.
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Offline simonbp

Re: 33ft core
« Reply #53 on: 02/12/2008 03:04 PM »
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mikeh - 12/2/2008  8:50 AM

The flight rate didn't kill the Saturn V, Nixon and Congress with their lack of funding and canceled programs did the job.

Close, but wrong dead president. Johnson actually killed the Saturn V in 1967 by not approving any further construction beyond the initial batch. Flight rates had nothing to do with it...

Simon ;)

Offline iamlucky13

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Re: 33ft core
« Reply #54 on: 02/12/2008 09:10 PM »
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Sid454 - 11/2/2008  7:33 PM

the larger faring could be great for the LSAM and allow it to be a shorter wider design which is better for both stability and safety of the astronauts.

Safety probably isn't a big issue there. The LEM was definitely skinnier than the LSAM concepts so far studied, and NASA figured out how to control it reasonably enough. Or consider the Delta Clipper. However, a notable optimization issue brought up in the ESAS was how to get payloads off of the LSAM and onto the lunar surface easily. A wider lander accomodates this task more easily by allowing the engines to be placed next to the payload (on outriggers essentially) rather than below it.

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But on cost I have to agree with clongton here flight rate is everything in costs so maybe we shouldn't be trying to make the biggest rocket possible but instead the biggest one that can find a good flight rate and escape the Saturn V's fate if that means two big launches vs one big one and one small one so be it.

Not directly addressing costs, but as far as sustaining the Ares V, consider NASA is talking about ~2 flights per year (whether they follow through on that, I don't know). The Delta IV is currently running about 1.5 flights per year counting all variants.

Ultimately though, it comes down to balancing the costs of a second line of infrastructure vs. the higher costs per launch of a system like Direct. I have no clue how that works out.

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My biggest fear with Ares is the program could be canceled before Ares V  flies and then we would be stuck in LEO in a situation a lot worse then the one we are in now.

Very much agree.

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Also JPL will get screwed out of an opportunity to have an HLLV to play with and I'd like to see things like an 8M optical space telescope and a Jupiter icy moon orbiter.

Also being able to perform missions with out those time wasting gravity assist flybys would be great.

Giant missions like JIMO seem unlikely, considering at the time of cancellation I think it was staring down the barrel of a $5 billion+ pricetag. Time doesn't typically matter too much on most deep space missions if you can save a few million by going with a smaller launch vehicle or add more instruments. Pluto isn't going anywhere in the next few years, although on the flip side of the coin, some of the original mission scientists and engineers might.

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