Re: Model Rocket Booster Engine for Picosatellite
David; There are some much bigger motors! Ask the Level-3 rocketry folks! Anyway a cluster of medium sized motors could be fired individually as required to raise altitude. I would think that SRB's would be more reliable and safer than hypergolic used on previous Oscars. There would of course be a lot of heat in the rocket casings that would need to be dissipated.
How would attitude be controlled so the thrust is in the correct direction? Spin stabilization about the maximum moment off inertia axis is probably the best choice. This would require a magnetic torquing system.
Another issue is the thrust needs to be directed through the spacecraft's center-of-mass or there will be stability problems. How would a cluster be fired individually with each, in turn, directed through the center of mass? That's a complex design problem.
One more issue is that when you carry multiple motors, the first must accelerate the mass of the unfired motors, so the early firing will be less effective. The mass of the spent casings will need to be accelerated buy the subsequent motor firings.
You do have some work to do before you have a practical solution.
73, Ken N2WWD
Sent from my iPad
On Jan 17, 2012, at 3:44 PM, Joe Leikhim rhyolite@nettally.com wrote:
David; There are some much bigger motors! Ask the Level-3 rocketry folks! Anyway a cluster of medium sized motors could be fired individually as required to raise altitude. I would think that SRB's would be more reliable and safer than hypergolic used on previous Oscars. There would of course be a lot of heat in the rocket casings that would need to be dissipated.
-- Joe Leikhim
Leikhim and Associates Communications Consultants Oviedo, Florida
www.Leikhim.com
JLeikhim@Leikhim.com
407-982-0446
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I have developed the perfect solution;
A gatling gun type canister for the rocket motors would solve all of your objections per below:
On 1/17/2012 4:22 PM, Ken Ernandes wrote:
How would attitude be controlled so the thrust is in the correct direction? Spin stabilization about the maximum moment off inertia axis is probably the best choice. This would require a magnetic torquing system.
Yes just like other missions.
Another issue is the thrust needs to be directed through the spacecraft's center-of-mass or there will be stability problems. How would a cluster be fired individually with each, in turn, directed through the center of mass? That's a complex design problem.
A motorized canister with 6 to 8 motors aligned such that the active motor is aligned through the COM. Picture a revolver or gatling gun.
One more issue is that when you carry multiple motors, the first must accelerate the mass of the unfired motors, so the early firing will be less effective. The mass of the spent casings will need to be accelerated buy the subsequent motor firings.
Spent casings would be ejected using the ejection charge normally used for deploying a parachute. Just as with any fuel, the mass of the unfired fuel will create mass for the initial firings.
You do have some work to do before you have a practical solution.
Work is done. Took about 4 minutes. Coffee break now!
73, Ken N2WWD
Sent from my iPad
On Jan 17, 2012, at 3:44 PM, Joe Leikhimrhyolite@nettally.com wrote:
David; There are some much bigger motors! Ask the Level-3 rocketry folks! Anyway a cluster of medium sized motors could be fired individually as required to raise altitude. I would think that SRB's would be more reliable and safer than hypergolic used on previous Oscars. There would of course be a lot of heat in the rocket casings that would need to be dissipated.
-- Joe Leikhim
Leikhim and Associates Communications Consultants Oviedo, Florida
www.Leikhim.com
JLeikhim@Leikhim.com
407-982-0446
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This is a fun thought exercise. The gatling gun is one option. I prefer something with no moving parts. It should be possible (not easy) to center one engine on each side. That would be six engines. Once in orbit take the time to stabilize the satellite along the first axis before firing the first engine to boost the orbit. Repeat the process up to 5 times. Wow - This is rocket science!
73, Joe kk0sd
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Joe Leikhim Sent: Tuesday, January 17, 2012 5:33 PM To: Ken Ernandes Cc: amsat-bb@amsat.org Subject: [amsat-bb] Re: Model Rocket Booster Engine for Picosatellite
I have developed the perfect solution;
A gatling gun type canister for the rocket motors would solve all of your objections per below:
On 1/17/2012 4:22 PM, Ken Ernandes wrote:
How would attitude be controlled so the thrust is in the correct
direction? Spin stabilization about the maximum moment off inertia axis is probably the best choice. This would require a magnetic torquing system.
Yes just like other missions.
Another issue is the thrust needs to be directed through the spacecraft's
center-of-mass or there will be stability problems. How would a cluster be fired individually with each, in turn, directed through the center of mass? That's a complex design problem.
A motorized canister with 6 to 8 motors aligned such that the active motor is aligned through the COM. Picture a revolver or gatling gun.
One more issue is that when you carry multiple motors, the first must
accelerate the mass of the unfired motors, so the early firing will be less effective. The mass of the spent casings will need to be accelerated buy the subsequent motor firings.
Spent casings would be ejected using the ejection charge normally used for deploying a parachute. Just as with any fuel, the mass of the unfired fuel will create mass for the initial firings.
You do have some work to do before you have a practical solution.
Work is done. Took about 4 minutes. Coffee break now!
73, Ken N2WWD
Sent from my iPad
On Jan 17, 2012, at 3:44 PM, Joe Leikhimrhyolite@nettally.com wrote:
David; There are some much bigger motors! Ask the Level-3 rocketry folks! Anyway
a cluster of medium sized motors could be fired individually as required to raise altitude. I would think that SRB's would be more reliable and safer than hypergolic used on previous Oscars. There would of course be a lot of heat in the rocket casings that would need to be dissipated.
-- Joe Leikhim
Leikhim and Associates Communications Consultants Oviedo, Florida
www.Leikhim.com
JLeikhim@Leikhim.com
407-982-0446
Note to GMail Account users. Due to an abnormally high volume of spam
originating from bogus GMail accounts, I have found it necessary to block certain GMail traffic. Please phone me if you believe your message was not received.
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (3)
-
Gary "Joe" Mayfield -
Joe Leikhim -
Ken Ernandes