Safe Solid Rocket Design for Small Satellites

[Winston]

I thought this might be a way to avoid hazmat with what is in effect a dual-solid hybrid. Then I looked at the tech paper linked to below. Uh, nope! Still interesting though.

High DeltaV (Safe) Solid Propulsion System for Small Satellites

https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=3372&context=smallsat

[video=youtube;VeSdGMi7md4]https://www.youtube.com/watch?v=VeSdGMi7md4[/video]

 

[K'Tesh]

I'd be worried about any kind of particles that may be released in the burn process. That would only add to the problem of space junk

 

[aerostadt]

A vacuum Isp of 260 sec. is about the same as an AP composite propellant. Doesn't sound like it is worth the trouble. I think some salesmanship is involved here.

 

[dhbarr]

A vacuum Isp of 260 sec. is about the same as an AP composite propellant. Doesn't sound like it is worth the trouble. I think some salesmanship is involved here.

I'm trying to understand how this could be considered 'safer', but I'm probably missing something. I suppose perhaps the upper grain has similar characteristics to APCP, but the lower one is fairly inert?

 

[rstaff3]

How I read it is that unlike APCP, which has the fuel and oxidizer mixed together, the one described above has the fuel and oxidizer separated until combustion is started.

 

[dhbarr]

How I read it is that unlike APCP, which has the fuel and oxidizer mixed together, the one described above has the fuel and oxidizer separated until combustion is started.

I caught that, but unless each of the grains is significantly more difficult to ignite, well... it's not like the flame front from one is going to respect the other's life choices.

 

[rstaff3]

Hope the ignition system is safer too.

 

[Winston]

I'm trying to understand how this could be considered 'safer', but I'm probably missing something. I suppose perhaps the upper grain has similar characteristics to APCP, but the lower one is fairly inert?

Same here, although it must be. Anyway, a look at the the PDF at the link above the video made me realize that it would still require hazmat shipping and would be too expensive for hobby use given the fuel component grain composition alone.

 

[Incongruent]

The fuel portion is heated to release the flammable gas hydrogen and high energy nitrogen. Then they pass through an oxidizer section which reacts to the hot gasses like a hybrid motor, just with solid fuel and (at that point) gaseous fuels. This way, since there aren't volitile liquids or mixed solid fuels, and explosion or fire is much less likely and so the CubeSats using this propulsion method can be launched as filler payloads (to get a rocket to the maximum launch weight and fill up the excess space inside the payload fairing) to increase cost-effectiveness of large launches. In the CubeSats get launched this way, (A significant portion of CubeSats) normal propulsion is unusable, as right next to the CubeSat you'll have a satellite worth around 500 million dollars. The risk is just too high.

 

[Winston]

The fuel portion is heated to release flammable gasses, hydrogen and methane I believe. Then they pass through an oxidizer section which reacts to the hot gasses like a hybrid motor, just with solid fuel and (at that point) gaseous fuels. This way, since there aren't volitile liquids or mixed solid fuels, and explosion or fire is much less likely and so the CubeSats using this propulsion method can be launched as filler payloads (to get a rocket to the maximum launch weight and fill up the excess space inside the payload fairing) to increase cost-effectiveness of large launches. In the CubeSats get launched this way, (A significant portion of CubeSats) normal propulsion is unusable, as right next to the CubeSat you'll have a satellite worth around 500 million dollars. The risk is just too high.

Thanks. That's from the paper's abstract which I should have read. I went straight to the fuel and oxidizer portion of the paper to investigate the chance of this method avoiding hazmat and saw AP and a "high-H, high-N explosive material" (TAGN) which I incorrectly assumed was an "explosive" in the usual interpretation of that word and probably detonable but if you read further into the abstract than the portion you quoted, they say it is non-detonable. However, since the TAGN would probably be too expensive to manufacture for hobbyist motors and since either component would probably require hazmat shipping individually, I didn't investigate further since possible hazmat avoidance of a "solid hybrid" was the only advantage for hobbyists that I saw.