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Orbital rockets are now easy, page 2: solid-rockets for cube-sats.


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I suggested in a post to my blog that solid rocket motors available to amateurs working in high power rocketry can be used as the basis for constructing orbital rockets that are within the capabilities of most universities to build:

Orbital rockets are now easy, page 2: solid-rockets for cube-sats.
http://exoscientist.blogspot.com/2017/08/orbital-rockets-are-now-easy-page-2.html

 Comments on its feasibility are welcome, especially simulations using Kerbal, i.e., via Realism Overhaul.

  Bob Clark

Edited by Exoscientist
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Tell that to Sandia National Labs, the University of Hawaii, and Aerojet Rocketdyne. Super Strypi didn't make it to orbit, and they are hardly ametuers. 

 

Edited by tater
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Don't forget the SS-520-4.

But in retrospective, most early rockets ARE solid AND small (payload). So it's only about getting things right.

But once you do so succesfully, you've erased "Amateur" off your ranks.

Edited by YNM
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4 hours ago, tater said:

Tell that to Sandia National Labs, the University of Hawaii, and Aerojet Rocketdyne. Super Strypi didn't make it to orbit, and they are hardly ametuers. 

 

 

 The simplicity is due to using the same solid motors which amateurs have been firing for years. What's extra required is staging and stacking.

  Bob Clark

 

Edited by Exoscientist
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2 minutes ago, Exoscientist said:

The simplicity is due to using solid motors which amateurs have been firing for years.

  Bob Clark

Well, what's the average reliability for all the parts involved ? 90% ?

Also, as I have said, if some "amateurs" get an orbital-class rocket reliably, they're not just successful in making one that works, they have also succeeded in erasing off the title "amateur" from their works.

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36 minutes ago, tater said:

I'm pretty sure Aerojet Rocketdyne has been firing their solids for years, too.

 For Aerojet and other large aerospace companies, there is no market for just a few kilo launchers. They prefer launchers that would bring in millions of dollars per launch. Such large solid rocket launchers have been made since the early sixties by the large aerospace companies.  

 BTW, the form of the launcher is similar to an "asparagus launcher" in that it uses multiple same size motors clustered together. But the idea of the asparagus launcher also includes the idea that the motors stage by peeling off in pairs. I didn't include that because the simulation program I used only allowed three stages. But the peeling off in pairs idea should increase the payload.

 

  Bob Clark

Edited by Exoscientist
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55 minutes ago, Exoscientist said:

 For Aerojet and other large aerospace companies, there is no market for just a few kilo launchers. They prefer launchers that would bring in millions of dollars per launch. Such large solid rocket launchers have been made since the early sixties by the large aerospace companies.

...

  Bob Clark

Wrong. The difference whether your rocket will only do suborbital or orbital is also about the paylod. Super Strypi and SS-520-4 is done from sounding rockets, Strypi and SS-520. They only put lighter payloads and change the trajectory and firing sequence, that's it.

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I went and read the blog, and was really wondering on the suggested "amature" method of booster construction.  While I'd agree that it is quite likely that you could manufacture carbon tubes at reasonable cost, this still leaves the issue with filling them with ammonium perchlorate (and similar high-Isp cores).  The (currently pinned) amature rocket to orbit thread considered "off the shelf" ammonium perchlorate boosters (for the last stage) and possibly homemade "candy rockets" (to get the first stage going), but I don't think anybody considered whipping up their own ammonium perchlorate and filling a homemade tube: that type of thing should be done with sufficient automation to be done without human involvement and with certainty that an "all clear" whistle can be blown to allow the humans to enter.  This type of thing is possible in an ongoing commercial environment, but I have my doubts about amature builders.

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24 minutes ago, p1t1o said:

Is the guidance of an orbital rocket not a significant challenge?

Compared to merely building a sounding rocket with the equivalent dV?

True, but as with old ICBMs turned launchers, if your rocket can easily fulfill high to very high accuracy on suborbital trajectories, the orbital version ones shouldn't take much difference.

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17 hours ago, YNM said:

Wrong. The difference whether your rocket will only do suborbital or orbital is also about the paylod. Super Strypi and SS-520-4 is done from sounding rockets, Strypi and SS-520. They only put lighter payloads and change the trajectory and firing sequence, that's it.

 The Super Strypi was planned to get 300 kg to LEO for $15 million, or about $50,000 per kilo. The large aerospace companies are just not interested in launchers that don't cost in the millions of dollars range.

Rail-launched Super Strypi Rocket Packed with Cubesats Fails in Debut.
by Mike Gruss — November 4, 2015

The Super Strypi launcher was expected to be able to place as much as 300 kilograms of payload into low Earth orbit.

Based on designs developed by the U.S. Department of Energy’s Sandia National Laboratory in New Mexico as part of nuclear testing programs dating back to the 1960s, the Super Strypi ultimately was expected to cost about $15 million per mission, officials had said.

http://spacenews.com/rail-launched-super-strypi-rocket-packed-with-cubesats-fails-after-liftoff/

 The small solid motor launchers in contrast would only get about 1kg to 10kg to orbit for a cost only in the tens of thousands of dollars range.

 

 

10 hours ago, p1t1o said:

Is the guidance of an orbital rocket not a significant challenge?

Compared to merely building a sounding rocket with the equivalent dV?

 

 You're right about the guidance being a significant issue. But some earlier rockets such as the rocket that sent the first Explorer 1 satellite to orbit had simple systems that used spinning platforms and the gyroscope effect to maintain stability. They didn't have the accuracy in their final orbital position but they did allow the rocket to reach orbit.

 

10 hours ago, wumpus said:

I went and read the blog, and was really wondering on the suggested "amature" method of booster construction.  While I'd agree that it is quite likely that you could manufacture carbon tubes at reasonable cost, this still leaves the issue with filling them with ammonium perchlorate (and similar high-Isp cores).  The (currently pinned) amature rocket to orbit thread considered "off the shelf" ammonium perchlorate boosters (for the last stage) and possibly homemade "candy rockets" (to get the first stage going), but I don't think anybody considered whipping up their own ammonium perchlorate and filling a homemade tube: that type of thing should be done with sufficient automation to be done without human involvement and with certainty that an "all clear" whistle can be blown to allow the humans to enter.  This type of thing is possible in an ongoing commercial environment, but I have my doubts about amature builders.

 

 Producing your own ammonium perchlorate can indeed be quite dangerous if you don't know what you're doing. That's why I suggest in the blog post using the commercially produced solid motors sold to amateurs who do experimental flights in high power rocketry.

  Bob Clark

Edited by Exoscientist
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8 hours ago, Exoscientist said:

The small solid motor launchers in contrast would only get about 1kg to 10kg to orbit for a cost only in the tens of thousands of dollars range.

...

  Bob Clark

Then I beg to differ with SS-520, Scout, Aerobee, Black Brant, others from "smaller" nations...

It's not that they're uninterested, the customer would more often also be uninterested. Side-payload on bigger rockets costs less I think ? So these small rockets ends up only used as suborbital rockets. If someone were willing to contact them to be used as orbital rockets, I believe only minimal amount of retrofit is required.

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22 hours ago, p1t1o said:

Is the guidance of an orbital rocket not a significant challenge?

Compared to merely building a sounding rocket with the equivalent dV?

At least one of Japan's small rockets designed for orbit (not sure if it succeeded) didn't have a proper guidance system and simply was angled and rode the gravity turn to orbit.  This was presumably due to Japanese hostility to nuclear weapons extending to potential ICBMs.

There are plenty of parts of 1950s state of the art that are hard to duplicate.  I can't believe that guidance systems are one of them.

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1 hour ago, wumpus said:

There are plenty of parts of 1950s state of the art that are hard to duplicate.  I can't believe that guidance systems are one of them.

The basic problem is that even the most basic inertial guidance system is a complex piece of precision equipment.

 

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2 hours ago, DerekL1963 said:

The basic problem is that even the most basic inertial guidance system is a complex piece of precision equipment.

Does it have to be based on inertia?  I'd expect that using radio guides (checking phase changes of a few locked signals on the ground) would be good enough for the first crucial bits (especially while still in the atmosphere and avionics will still work).  If you leave the atmosphere at the right angle (I suspect you need it to the right minute if not second), I'd expect spin stablizing to be enough.  It should also be easy enough for arbitrary accuracy, although you might need a second array at sea (you will eventually have a big blob of plasma pointed at the launch site, for any distance away from the launch site).

Putting the guidance system below the final stage was a common trick.  I know Vanguard managed to do it successfully (and I don't think guidance was the cause of earlier Vanguard failures).  Not sure if avionics is enough.

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1 hour ago, tater said:

If it's so easy, just do it already and show idiots like Sandia National Laboratories how it's done.

Are you supplying the $15M?  Super Strypi failed thanks to a motor failure, something that only has been claimed as "easy" by the guy who started this thread.  Duckduckgo sees a site that appears to be related to Super Strypi "http://www.rocket.com/super-strypi", but it appears to not be configured.  The search blurb states "... without a complex guidance system", so I wouldn't count on them using a full blown guidance system either (although I would look for any kind of off the shelf system for that kind of money, and then check to see what resolution a wiimote has).

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8 hours ago, wumpus said:

Does it have to be based on inertia?  I'd expect that using radio guides (checking phase changes of a few locked signals on the ground) would be good enough for the first crucial bits

Radio guidance requires a functional and fairly accurate radar - still a complex piece of precision equipment.
 

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21 hours ago, YNM said:

Then I beg to differ with SS-520, Scout, Aerobee, Black Brant, others from "smaller" nations...

It's not that they're uninterested, the customer would more often also be uninterested. Side-payload on bigger rockets costs less I think ? So these small rockets ends up only used as suborbital rockets. If someone were willing to contact them to be used as orbital rockets, I believe only minimal amount of retrofit is required.

 

 If they are orbital, they are still million dollar rockets. Both DARPA and the U.S. Army funded programs to develop orbital rockets for payloads in the few 10's of kilos range for the radical low price of $1 million per launch. Both those programs failed. 

 These were using liquid-fueled rockets though, which are more complicated than simple solid rocket motors. I'm suggesting using essentially "off-the-shelf" high power solid motors such a low cost, small payload rocket can be produced.

 

  Bob Clark

Edited by Exoscientist
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46 minutes ago, Exoscientist said:

 

 If they are orbital, they are still million dollar rockets. Both DARPA and the U.S. Army funded programs to develop orbital rockets for payloads in the few 10's of kilos range for the radical low price of $1 million per launch. Both those programs failed. 

 These were using liquid-fueled rockets though, which are more complicated than simple solid rocket motors. I'm suggesting using essentially "off-the-shelf" high power solid motors such a low cost, small payload rocket can be produced.

 

  Bob Clark

The complication here is that what you're actually advocating is essentially "gluing" four of these off the shelf motors together to make one larger one. This is not exactly a well known procedure, and I'm not entirely sure how reliable the end product is going to be, after all, for a solid rocket you want a reasonable uniform and continuous burn surface and the seams between these motors would be a big question mark. Just because one motor will work does not automatically mean that four stuck together will.

 

My other concern is thus:

Are the manufacturing tolerances on these things high enough that you can use them in a cluster? Assuming stacking four motors to form one larger one is fine and works perfectly, you're still clustering four of these larger engines together to form a first stage. Are they manufactured consistently enough that you can say, with confidence, that one won't burn out half a second later than the others, or ramp up to full thrust slightly later, or make more/less thrust than the others? If there's no active guidance onboard then these things are absolutely critical.

Edited by Steel
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