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#20 by simonbp on 26 Dec, 2011 20:47
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Another alternative would be a 3-SB topped by a 4xRL10 LH2 stage that weighed about 44 tonnes. Such a stage could be 4 meters diameter and probably 15 meters long. This rocket would stand a couple of meters taller than the RD-0120 rocket, but would lift 10 tonnes to LEO.
Hmmm... make that just a little bit bigger and you should be able to launch a CST-100 (especially of the LAS is used for the circ burn). I'm not sure why you would, but there it is... -
#21 by Prober on 26 Dec, 2011 20:49
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I'm still not sure what the goal is, but if the intent is to use five segment booster topped by a different upper stage, here are a couple of ideas.
First, note that five segment booster shouldn't be used unless the payload is going to be heavy. This is, after all, the world's most powerful rocket motor. It shouldn't be used to lift just 8.2 tonnes to LEO. Falcon 9 can do that.
Speaking of Falcon 9, a Merlin Vacuum powered second stage atop a five segment booster can be considered. Four Merlin Vacs, perhaps with shorter nozzles than on Falcon 9, would result in 13 or more tonnes to LEO. Adding a third stage very similar to the Falcon 9 second stage would result in a rocket able to lift 22 or more tonnes to LEO or 8 tonnes to GTO. Not too shabby for a rocket that uses only low energy propellants. This rocket would stand about as tall as Ares I if the upper stages were about the same diameter as the booster.
An all-solid alternative might use a 5-seg first stage, a 2-seg second stage, a Castor 120 type third stage, and a Castor 30XL type fourth stage to lift 17 tonnes to LEO. ATK might call it "Athena V".
- Ed Kyle
No around 18,000 lbs and the early ideas are best thus far. The Merlin Vacs might work, but SpaceX doesn't play well with others.
Alot of the features I've been looking for just fall right into place, the more i search it out. It may turn out to be more like a "Titan V" than "Athena V"
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#22 by edkyle99 on 26 Dec, 2011 22:30
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No around 18,000 lbs
For only 8.17 tonnes (18,000 lbs) to a 51.6 deg orbit, something shrunk down to only an "Athena III"-like 2.5 segment first stage topped by a 37 tonne gross liquid hydrogen second stage (powered by three RL10 engines) could work. Again, this would stand about half as tall as Ares I or Liberty, and cost much less too.
- Ed Kyle
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#23 by Downix on 26 Dec, 2011 22:40
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Think on this a bit Ed. The Athena III uses the same segments as Liberty. A smart solution would be a scalable solution from 7 tonnes to much more. 2 segment, 3 segment, 4 segment, 5 segment. Utilizing another high-thrust second stage (Castor 120 would be ideal here) with a high-energy orbital maneuvering stage (Centaur or DCSS for instance) would work very well.No around 18,000 lbs
For only 8.17 tonnes (18,000 lbs) to a 51.6 deg orbit, something shrunk down to only an "Athena III"-like 2.5 segment first stage topped by a 37 tonne gross liquid hydrogen second stage (powered by three RL10 engines) could work. Again, this would stand about half as tall as Ares I or Liberty, and cost much less too.
- Ed Kyle -
#24 by Prober on 26 Dec, 2011 23:37
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Wow ED & Downix
Guess I better do more research on "Athena".
http://forum.nasaspaceflight.com/index.php?topic=20986.0 ah, wouldn't mind working with LM & ATK
Got the Titan name cause they made very decent use of solids and there's alot of history and ideas available from them.
No way interested in their toxic fuels
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#25 by Jason1701 on 27 Dec, 2011 00:01
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Think on this a bit Ed. The Athena III uses the same segments as Liberty. A smart solution would be a scalable solution from 7 tonnes to much more. 2 segment, 3 segment, 4 segment, 5 segment. Utilizing another high-thrust second stage (Castor 120 would be ideal here) with a high-energy orbital maneuvering stage (Centaur or DCSS for instance) would work very well.No around 18,000 lbs
For only 8.17 tonnes (18,000 lbs) to a 51.6 deg orbit, something shrunk down to only an "Athena III"-like 2.5 segment first stage topped by a 37 tonne gross liquid hydrogen second stage (powered by three RL10 engines) could work. Again, this would stand about half as tall as Ares I or Liberty, and cost much less too.
- Ed Kyle
Burn profiles have to be tailored for the number of segments and require static fires. Switching the segments is much more complicated and expensive than it sounds. -
#26 by edkyle99 on 27 Dec, 2011 00:24
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Burn profiles have to be tailored for the number of segments and require static fires. Switching the segments is much more complicated and expensive than it sounds.
Different motor set ups would need different nozzles too. But some leeway seems possible if perfect optimization is not needed for every motor. NASA and ATK were, just a few months ago, contemplating an SLS motor that would have used four segments from the five segment motor, removing the middle segment but leaving the others, including igniter and nozzle segments, "as-is".
- Ed Kyle -
#27 by Downix on 27 Dec, 2011 03:00
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Only if you are aiming for perfect optimization. They did tests of this as late as 2006, firing segmented solid motors with less than optimal segments. While the burn was not 100% optimal, even with half the number of segments, they achieved 95% optimal burn. They found that optimizing for the maximum segments would allow for a solid burn with less segments. This is still good enough with the cost reduction that the lower payload lift vehicles would offer due to more production. The nozzle would need to be different, but the nozzles are not the expensive part of the equation here.
Think on this a bit Ed. The Athena III uses the same segments as Liberty. A smart solution would be a scalable solution from 7 tonnes to much more. 2 segment, 3 segment, 4 segment, 5 segment. Utilizing another high-thrust second stage (Castor 120 would be ideal here) with a high-energy orbital maneuvering stage (Centaur or DCSS for instance) would work very well.No around 18,000 lbs
For only 8.17 tonnes (18,000 lbs) to a 51.6 deg orbit, something shrunk down to only an "Athena III"-like 2.5 segment first stage topped by a 37 tonne gross liquid hydrogen second stage (powered by three RL10 engines) could work. Again, this would stand about half as tall as Ares I or Liberty, and cost much less too.
- Ed Kyle
Burn profiles have to be tailored for the number of segments and require static fires. Switching the segments is much more complicated and expensive than it sounds. -
#28 by simonbp on 27 Dec, 2011 04:07
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Utilizing another high-thrust second stage (Castor 120 would be ideal here) with a high-energy orbital maneuvering stage (Centaur or DCSS for instance) would work very well.
A stage with 1x AJ-26 with altitude nozzle would make a nice second stage, and could probably get away without a third stage. -
#29 by Prober on 27 Dec, 2011 14:09
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Believe we can make something work for the first and 2nd stages. On to the next problem.
Getting back into the details and ran into the real major issue with this project, infrastructure. The downside of Liberty was using the crawler and that huge 300 ft tower etc. We dealt with some of those issues but some new ones have crept up.
The only real low cost way to deal with the infrastructure issues is with railroad tracks. I’ve turned to Titan for some insight into how it was worked out at the cape.
http://forum.nasaspaceflight.com/index.php?topic=25799.0
Also have to deal with the weight issues and handling at a low cost of a 3-4 segment stage (safely) or the project is dead in the water. Review of 30 years of shuttle experience will help here. However, if an army of workers would be needed then liquids become more effective.
This video was an eye opener of the problem:
http://www.nasa.gov/multimedia/videogallery/index.html?media_id=74698561
http://www.nasa.gov/centers/kennedy/pdf/192935main_RRtrain08.pdf
Ideas….comments?
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#30 by Jim on 27 Dec, 2011 14:13
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Forget the SRB all together.
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#31 by Prober on 27 Dec, 2011 14:16
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Forget the SRB all together.
care to expand on that? any input in this brainstorming is welcome and won't be used against you.
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#32 by edkyle99 on 27 Dec, 2011 14:26
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Ariane 5 also uses rail both to roll out and to move the assembled boosters.
The only real low cost way to deal with the infrastructure issues is with railroad tracks. I’ve turned to Titan for some insight into how it was worked out at the cape.
Also have to deal with the weight issues and handling at a low cost of a 3-4 segment stage (safely) or the project is dead in the water.
http://www.sciencephoto.com/image/334636/530wm/S2200073-Ariane_5_solid_booster_being_carried_to_test_stand-SPL.jpg
U.S. launch rates are so low that on-pad assembly is possible. No need for a far-flung complex with separate assembly and launch sites.
- Ed Kyle -
#33 by simonbp on 27 Dec, 2011 15:03
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Yeah, for a big solid first stage at <5 flights per year, stack-on-pad is best. If launching from the Cape, though, some sort of weather protection is required. So, a basic infrastructure like Delta II used would be good: a static pad and tower and a retractable stacking/assembly facility on rails. If the flight rate gets high enough then, like Delta II, you just build a second pad.
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#34 by simonbp on 27 Dec, 2011 16:04
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So, playing around, I was able to get 8.26 tonnes (18.2 klb) to LEO delta v with a four-seg first stage and RP-1 second.
For the first stage, I assumed a direct 4/5 scaling of the Ares I first stage:
Loaded mass: 585.25 tonnes
Propellant mass fraction: 0.8575 (equal to Ares I FS)
Thrust: 12.5 MN
Isp: 267.4 s
For the second stage, I assumed basically a foreshortened Delta II first stage with RS-27A:
Wet mass: 100 tonnes
Propellant mass fraction: 0.934 (equal to Delta II first stage)
Thrust: 1.05 MN
Isp: 301 s
Diameter: 4 m
Length: 10 m
It would be a wild ride up, with almost 2g at liftoff, 7g at first stage burnout, 1g at second stage ignition, and 7g again at second stage burnout. That sounds bad, but isn't much worse than riding a Titan II.
The RS-27 would need to modified to air start, but considering it uses a hypergolic pack to self start anyways, that shouldn't be too hard.
EDIT: And a picture to show the relative size of the second stage.
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#35 by edkyle99 on 27 Dec, 2011 20:14
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So, playing around, I was able to get 8.26 tonnes (18.2 klb) to LEO delta v with a four-seg first stage and RP-1 second.
Since that stage has about the same mass properties as a Delta II first stage ....
I threw in a Delta 4 5-meter upper stage concept as well.
Re: end of burn g-forces, remember that the SRB thrust tails off significantly toward the end, by design.
http://thespaceport.us/forum/uploads/monthly_08_2011/post-15-0-43420300-1312600815_thumb.png
- Ed Kyle
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#36 by Prober on 28 Dec, 2011 05:27
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So, playing around, I was able to get 8.26 tonnes (18.2 klb) to LEO delta v with a four-seg first stage and RP-1 second.
Re: end of burn g-forces, remember that the SRB thrust tails off significantly toward the end, by design.
http://thespaceport.us/forum/uploads/monthly_08_2011/post-15-0-43420300-1312600815_thumb.png
- Ed Kyle
had an idea come to me.......has anyone ever had the solids reverse burn to "stage"? Would happen when the burn reaches that point before burnout.
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#37 by edkyle99 on 28 Dec, 2011 13:38
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So, playing around, I was able to get 8.26 tonnes (18.2 klb) to LEO delta v with a four-seg first stage and RP-1 second.
Re: end of burn g-forces, remember that the SRB thrust tails off significantly toward the end, by design.
http://thespaceport.us/forum/uploads/monthly_08_2011/post-15-0-43420300-1312600815_thumb.png
- Ed Kyle
had an idea come to me.......has anyone ever had the solids reverse burn to "stage"? Would happen when the burn reaches that point before burnout.
Minuteman missile third stages had, and maybe still have, thrust termination ports on their sides to provide some level of cutoff velocity precision. There may be other examples, but I'm not aware of any similar setup having ever been demonstrated (in flight) for a big solid motor like SRB. The only reason to implement something like this on a booster stage would be as part of a crew escape system, and even then I'm not sure it is feasible.
- Ed Kyle -
#38 by Prober on 28 Dec, 2011 14:38
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So, playing around, I was able to get 8.26 tonnes (18.2 klb) to LEO delta v with a four-seg first stage and RP-1 second.
Re: end of burn g-forces, remember that the SRB thrust tails off significantly toward the end, by design.
http://thespaceport.us/forum/uploads/monthly_08_2011/post-15-0-43420300-1312600815_thumb.png
- Ed Kyle
had an idea come to me.......has anyone ever had the solids reverse burn to "stage"? Would happen when the burn reaches that point before burnout.
Minuteman missile third stages had, and maybe still have, thrust termination ports on their sides to provide some level of cutoff velocity precision. There may be other examples, but I'm not aware of any similar setup having ever been demonstrated (in flight) for a big solid motor like SRB. The only reason to implement something like this on a booster stage would be as part of a crew escape system, and even then I'm not sure it is feasible.
- Ed Kyle
ahhh, interesting to chat about but might create more problems than its worth in this application.
focus now is Solid assembly, transport, storage. -
#39 by Prober on 28 Dec, 2011 16:53
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Horizontal assembly might be a better way to go? Any ATK people around? Do you assemble the test boosters horizontally?
