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Team Prometheus NSE-6 Mission Details

Posted by: stew_lilley - Mon May 16, 2011 1:59 am
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Team Prometheus NSE-6 Mission Details 
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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Wed May 25, 2011 4:16 pm
Aw thanks,

Heh didn't even think about plane fuel and boat fuel but I guess that makes sense. I don't think I'm gonna be able to make NSE-6 if it's still when you say, but no way in hell I miss the big one!

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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Wed May 25, 2011 4:50 pm
You'll be one of the first to know when we get a solid date for that one :) I cant wait myself! Exciting times at Team Prometheus! lol Today's the Day!

Monroe

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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Tue Jun 07, 2011 2:28 pm
Monroe, any updates on the NSE-6 mission? Has it happened yet?


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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Tue Jun 07, 2011 3:17 pm
Nope, not yet. We had some tracker problems, we just got them worked out we had a miscommunication with Greg at Big Red Bee that caused some hardware issues we had trouble solving. That delayed the launch.
I got to see my son for the first time in 10 years and that had priority over NSE-6 for a few days too. We blew a freeze plug on "Big Blue" our recovery truck.
Back on track today! Still need to do the ground launch I expect any day now we will do that. Any good day after that we will launch NSE-6.

I am considering adding the FPV/OSD and the Arducopter IMU to the space shot payload with the tracking 3 meter dish the 20W live video feed and the 7W remote control. We don't need the IMU as the space shot rocket goes straight up but it would send extra data and give us some remote control for other things.

All of that stuff would be on the balloon launch platform and not on the rocket it's self as there is no good way to put an antenna that would work well enough on the rocket. So NSE-6 still carries everything that would be on the space shot rocket.

We worked out a way to control attitude of the rocket for the N-Prize attempt during the third stage orbital insertion with a single FOG gyro that would keep a section of the rocket from spinning and using a cold gas jet to assist the gravity turn and keep it pointed in the right direction.

The only problem with project pilot was this turn. In it's arc into space there would be no aerodynamic drag to arc over the rocket and allow the horizon sensor to get the proper angle to fire the stage.

Kind of like throwing a javelin with assist where there is no aerodynamic drag to arc it over. Or even like a football does when thrown a long ways down field.

I had a talk with the FAA and it's going to take about a year to do the paperwork for the N-Prize and get it all worked out. So we are still plugging away at that.

That's where we are at today.

Monroe

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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Tue Jun 07, 2011 4:58 pm
Monroe,

It sounds like you're starting to converge toward the things I suggested a year and a half ago in the project description document. I think the live video link and remote control are essential for the suborbital and orbital launches, so it's good to see you're adding them. Will the NSE-6 rocket carry the electronics for the tracking and parachute recovery system for two stages? It still seems like you should have a mission between NSE-6 and the space shot that tests out a two-stage rocket.

Why would you need a fiber-optic gyro (FOG)? It seems that a MEMS gyro should be good enough, as long as the drift is compensated by horizon and sun detectors. In fact, if the rocket is spinning you really don't need the gyro. There was a discussion on the N-Prize forum about rocket steering ( http://n-prize.com/forum/viewtopic.php? ... 4&start=20 ) and it seems that spin stabilization won't work as well as I thought it would. You might need a different form of active guidance, such as thrust vanes or a gimballed motor nozzle.

The Project Pilot (or NOTSNIK) rocket used passive aerodynamic steering for all of it's stages except for the final one. The final stage was shaped like a wheel so that it had a large moment of inertia, which made a good mechanical gyro. NOTSNIK required that the lower stages put the satellite in an eccentric orbit, where the apogee was on the opposite side of the earth. The final stage required only enough impulse to circularize the orbit a bit so it wouldn't immediately re-enter the atomosphere after it completed its first orbit. It was a very low-tech design that didn't use active guidance.

It sounds like you are only planning on using 3 stages for the orbital mission. You may want to simulate that. That's going to be hard to do with the ISP of solid fuel rockets. If your planning on using your N-N two stage rocket as the first two stages your third stage will require a very large delta-v to achieve orbit. This approach is very different than the NOTSNIK aproach.

Dave


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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Tue Jun 07, 2011 5:31 pm
Dave
Active guidance like gimbaled motors and such is not going to happen. It's too heavy and complex for our mass ratio bottom line.
Mems gyro's suck and they will not work reliably enough for an orbital mission. Spin stabilization is a big factor with the FAA they like that and it reduces our dispersion analysis to a reasonable footprint.
Nope, Pilot was nearly out of the atmosphere when the third stage fired, that's why it failed, it kept the 70 degree angle too long.
Yep, NSE-6 has the two stage firing solution onboard.
It's 5 stages still. As far as anything in that document any orbital rocket would have to fall somewhere along those lines anyway Dave, that's a no-brainer.
Testing the two-stage on NSE-7, yeah we might. Depends on time and weather the FAA requires it. Looks like they wont though.

Monroe

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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Tue Jun 07, 2011 8:26 pm
Monroe,

Look at the N-Prize link in my previous post. Go back to the first page of the thread. My conclusion was that spin stabilization wouldn't be enough unless the rocket was really long, and was spinning really fast (6000 RPM?), and the motor had to have a very small tangential thrust vector. Spin stabilization works OK if there is some atmosphere or the delta-v is small, but we are talking about individual-stage delta-v's on the order of 2 km/s. In the N-Prize thread, I proposed a method of vectoring the thrust in the final stage by gimballing the rocket at the middle. However, this would add weight and complexity.

Yes, you're right about the altitude of NOTSNIK's third-stage burn. It was around 50 miles up when it fired. However, as you mentioned in your post at http://highpowerrocketry.blogspot.com/2 ... tsnik.html , the angle would have been 12 degrees at that point. Even with the feeble atmosphere at that altitude it was apparently enough to keep the rocket pointed into the direction of travel.

You mentioned a "third stage orbital insertion" in your earlier post, so I thought the rocket had only 3 stages. Normally, orbital insertion is done with the last stage. I think you under estimate the accuracy required to achieve orbit. It's definately not a "no-brainer". The number of stages was derived from a precise analysis of the launch trajectory based on the mass fraction and ISP of the motors. You aren't going to make orbit if you're off by a few percent on any of the parameters.

Dave


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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Tue Jun 07, 2011 11:37 pm
Dave
Yes it is a no-brainer it is a basic calculation and conclusion anyone that has to calculate it with the basic numbers known will come up with the same answer. That document doesn't work out any of the really hard problems with doing it either as far as I remember. Any relation to that document is purely incidental especially because nether myself or Stew ever really read it fully I find that interestingly funny.

Monroe

"Yes, you're right about the altitude of NOTSNIK's third-stage burn. It was around 50 miles up when it fired. However, as you mentioned in your post at http://highpowerrocketry.blogspot.com/2 ... tsnik.html , the angle would have been 12 degrees at that point. Even with the feeble atmosphere at that altitude it was apparently enough to keep the rocket pointed into the direction of travel."

It was pointed out to me by Henry Spencer on Arocket that I might be wrong about that and I agreed with him that not reaching the 12 degree angle would be due to the lack of air. after about 2 seconds thought I realized he was right and not I. He has the required experience to change my mind.

Our mission is based on "Project Pilot" It always has been based on the work of Howard Wilcox and I will not deviate much from that. Bottom line.
The only thing I'm really working out is the different launch platform. The simple guidance system is to correct the one problem with his basic design.

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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Wed Jun 08, 2011 1:50 pm
Monroe,

You may want to have Henry Spencer check his calculations again. The atmospheric density at 50 miles is about 1/64,000 of that at sea level. That's not a lot, but it should be enough to keep the rocket pointed into the direction of travel, especially if it has some spin. A rocket traveling at 10,000 MPH at 50 miles up would have the equivalent aerodynamic forces as one traveling at 40 MPH at sea level. 40 MPH is pretty slow, but it's enough to keep a football pointed into the direction of travel.

You said your plan is based on Project Pilot that Howard Wilcox ran. Do you think Howard Wilcox would have made such a blunder of the rocket not being pointed in the right direction when the third stage is fired? You really need to double check your math. The eccentric orbit of the NOTSNIK satellite is a direct result of the use of passive aerodynamic guidance.

I'm disappointed that you never read the project description document. It contains some useful information. I know that Stew read it because he made some detailed comments on it. Of course, a lot of the detailed calculations were in the spreadsheets that were posted on the Team Prometheus Yahoo group. However, that got lost when you deleted the group.

Dave


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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Wed Jun 08, 2011 3:35 pm
Dave
Save it for next year, right now we are working on the space shot. I've not started construction of the orbital rocket yet. We don't even know for sure what mass fraction we are going to get. Lots of testing left to do over the next few months after the space shot.
The form of guidance I mentioned cant hurt the project and we are going to make more progress doing the space shot. We need to build more hardware and fly it.
I'm a hands on kind of guy. I cant feel it if it's not in my hands. When I can put my hands on it I'll know if it feels right.
When I can feel the propellant in the casings and glide my hand over the Av-bay I'll know if she can make it. If she's lean and mean or a little chunky I'll know it. I'll trim her down until she cant take anymore and then we'll see her fly. Until then it's ALL speculation.
So just kick back for a while and enjoy our struggle to get the next mission done. Your missing all the fun :)

Monroe

P.S. No, just yesterday Stewart told me he never really read it. I don't know if anybody did. The reason for that document to me was we needed something at the time and at the time it was appreciated because it was what was needed. I knew it was just some calculations the same ones I've see a thousand times. I did check it over to make sure there where no gross errors.
It's not that it wasn't needed it's just that I knew the final product would end up being something different. In a perfect world calculations and speculations like that work. I knew by the time we got there it would all look different and it will.

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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Wed Jun 08, 2011 5:33 pm
Monroe wrote:
P.S. No, just yesterday Stewart told me he never really read it. I don't know if anybody did. The reason for that document to me was we needed something at the time and at the time it was appreciated because it was what was needed. I knew it was just some calculations the same ones I've see a thousand times. I did check it over to make sure there where no gross errors.
It's not that it wasn't needed it's just that I knew the final product would end up being something different. In a perfect world calculations and speculations like that work. I knew by the time we got there it would all look different and it will.

Wow, Stew didn't even read it. Now my feelings are really hurt. :) You do realize that the cold-air thruster that you guys just came up with was in the document 1.5 years ago, don't you.

(EDIT: I checked my archived email and found comments and suggestions from Stew on an earlier version of the Project Description document. They were dated July 28 and July 29, 2009, and they were both fairly detailed. So it seems that Stew forgot that he had read it almost 2 years ago.)

Would you mind if I posted the document here? Maybe others could benefit from it.


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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Wed Jun 08, 2011 8:22 pm
Dave
Why would I care? Go for it, if it will give you some kind of satisfaction and you'll leave us alone sure.

Monroe

I will say your calculations where too optimistic and I knew that at a glance. Isp and mass fractions are off and the drag calculations are left out as well as deviation calculations and plenty more good stuff. Your gonna fall short bottom line your delta v is not enough in reality.
Main reason I stopped looking at it was the 20% margin I asked for was missing! These kind of calculations almost always end up 20% short that's always been my experience in real life and it might be 25% in this case anyway.

What we end up launching will be an entirely different animal.

It's also the reason I really don't believe CSXT did not actually make space. There is no real proof and I'll never be convinced they made it. We will prove it by a margin sufficient enough there will be no doubt.

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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Wed Jun 08, 2011 9:22 pm
DaveHein wrote:
Would you mind if I posted the document here? Maybe others could benefit from it.

Monroe wrote:
Dave
Why would I care? Go for it, if it will give you some kind of satisfaction and you'll leave us alone sure.

Monroe

Monroe,

The project description document is posted at http://home.swbell.net/davehein/tppd5.doc . I simulated the rocket described in the document, and of course it was able to orbit in the simulation. The video that you have on your website was generated from the output of the simulator. The simulation included aerodynamic drag.

The Isp's were based on commercially available propellant when adjusted for a vacuum. The mass fraction was a target derived from the mass fraction of the space shuttle's SRBs. The Isp's and mass fractions are very aggressive, and there is a good chance that they could not be achieved in practice. The intention was to adjust the specification once better numbers came in. Your 20% to 25% margin could be factored in at any time.

Most of the details on the angles of the stage firings, and the timing were posted on the Yahoo group, but all that information was lost when you deleted the group. Much of it can be inferred from the simulation video.

Dave


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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Wed Jun 08, 2011 10:35 pm
Dave
Oh, you win that proves it! lol Your gonna have to argue with yourself for a while you refuse to see and I don't have the time or inclination. What if your plan would work? You going to prove it? Otherwise it's just an intellectual exercise.

Monroe

It's pretty feeble to argue something that's not going to fly anyway. You build it I'll be the first one to clap. Till then...

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Post Re: Team Prometheus NSE-6 Mission Details   Posted on: Thu Jun 09, 2011 2:57 pm
Monroe wrote:
Oh, you win that proves it! lol Your gonna have to argue with yourself for a while you refuse to see and I don't have the time or inclination. What if your plan would work? You going to prove it? Otherwise it's just an intellectual exercise.

Monroe,

I'm not trying to "argue", I'm just making corrections and suggestions that will help you achieve your goals. I doubt if I would ever build the rockets in the plan, but I'm hoping that you do. :) I think as time goes on you will eventually converge toward what's in the plan. As you said, it's a no-brainer.

Dave


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