RCS Challenge

[Lt. Snakestrike]

Some of you may have noticed that I've been pretty inactive on the forum lately. Part of that is school, of course, but I've also been working on an aerospace project.

The club I'm in has a problem: they want to take videos from payloads in their balloon launches. In the past, they've tried, but the payloads are usually spinning really quickly. From what we've been told, usually the rates are at or about one rotation per second... Anyone wanna watch video like that?

Anyways, our job was to create a system to stabilize our payload's rotation around the vertical access. And, after 2 months... It flew today.

Initial Design:

Final:

I almost didn't blot out the number, but then I remembered... people are stupid.

The Balloons: One for RCS, one for Radiation detection.

I took a video of the launch, and I'll upload that once I get home.

It'll be some time before we actually recover the balloon and payloads. I'm looking forward to seeing the data. We also had a camera onboard, but we had issues getting it working, and it wasn't running at the time of launch...

Anyways, I look forward to the results.

 

[TtTOtW]

That looks like some good work, Lieutenant!

 

[SupremeDorian]

I read the title and thought it was going to be another one of these..

 

[Blazer Ayanami]

Some of you may have noticed that I've been pretty inactive on the forum lately. Part of that is school, of course, but I've also been working on an aerospace project.

The club I'm in has a problem: they want to take videos from payloads in their balloon launches. In the past, they've tried, but the payloads are usually spinning really quickly. From what we've been told, usually the rates are at or about one rotation per second... Anyone wanna watch video like that?

Anyways, our job was to create a system to stabilize our payload's rotation around the vertical access. And, after 2 months... It flew today.

Initial Design:
View attachment 28536

Final:
View attachment 28537

View attachment 28538

View attachment 28540
I almost didn't blot out the number, but then I remembered... people are stupid.

The Balloons: One for RCS, one for Radiation detection.
View attachment 28541

I took a video of the launch, and I'll upload that once I get home.

It'll be some time before we actually recover the balloon and payloads. I'm looking forward to seeing the data. We also had a camera onboard, but we had issues getting it working, and it wasn't running at the time of launch...

Anyways, I look forward to the results.

Dude thats awesome!

I read the title and thought it was going to be another one of these..

Me too! But then I looked at the person who created the challenge and said: "Nah, this must be something interesting. Let me see what he's up to."

 

[Lt. Snakestrike]

Lol, There's a reason it's in non-sfs and not challenges.

 

[Lt. Snakestrike]

I just found out, the payloads landed a little over 60 miles (100 km) east of the launch site. Looking forward to recovery.

 

[DoctorEvo]

That's really awesome. I feel like there's probably a simpler, passive solution, but considering this came out of Huntsville I guess it's no surprise you turned to rockets to solve your problem.

 

[SM84CE]

I read the title and thought it was going to be another one of these..

Yeah... same. I thought it would be a Mars return Mission with ONLY RCS...

But anyways, where are you in the picture? Or are you in the payload?

 

[Lt. Snakestrike]

That's really awesome. I feel like there's probably a simpler, passive solution, but considering this came out of Huntsville I guess it's no surprise you turned to rockets to solve your problem.

What kind of solution are you thinking of?
Actually, the one solution I do know of is a gimbal on the camera, but it's not as applicable, and I don't think it'd work once the rotation gets fast enough anyway. Once I get the video uploaded, you'll see. The wind likes to just send everything flying. Also, fins or other aero stabilization you normally think of wouldn't work, it'd actually pry make it worse. It isn't like a rocket in that way.

 

[Lt. Snakestrike]

Yeah... same. I thought it would be a Mars return Mission with ONLY RCS...

But anyways, where are you in the picture? Or are you in the payload?

Oh, I'm taking all these pictures. No face reveal lol.

 

[DoctorEvo]

What kind of solution are you thinking of?
Actually, the one solution I do know of is a gimbal on the camera, but it's not as applicable, and I don't think it'd work once the rotation gets fast enough anyway. Once I get the video uploaded, you'll see. The wind likes to just send everything flying. Also, fins or other aero stabilization you normally think of wouldn't work, it'd actually pry make it worse. It isn't like a rocket in that way.

My first thought was de-spin weights or a long boom for more rotational inertia. Both should smooth things out somewhat, though if there's a consistent disturbance in a certain direction, either one could eventually accumulate a high rotation rate as well. So some kind of damping, either active or passive, would be ideal. As far as passive options go, the most obvious option is indeed aerodynamic - perhaps not fins, in the conventional sense, but paddles or balls or some other sort of drag-producing object on the ends of a boom. A quick google search turned up a few examples of boom-stabilized balloon payloads, as well as this study on the topic.

 

[Lt. Snakestrike]

My first thought was de-spin weights or a long boom for more rotational inertia. Both should smooth things out somewhat, though if there's a consistent disturbance in a certain direction, either one could eventually accumulate a high rotation rate as well. So some kind of damping, either active or passive, would be ideal. As far as passive options go, the most obvious option is indeed aerodynamic - perhaps not fins, in the conventional sense, but paddles or balls or some other sort of drag-producing object on the ends of a boom. A quick google search turned up a few examples of boom-stabilized balloon payloads, as well as this study on the topic.

Thank you, that's actually really interesting. I'd always assumed that adding aero surfaces would just worsen the problem. I guess it's pry cause lateral movement, but resist rotation. Makes sense. I'm more interested in high altitude though tbh, and the thicker ropes is a good idea, but honestly something my club pry won't pursue because of the added weight and complexity... idk.

 

[Lt. Snakestrike]

And when you look at active, RCS is actually pry one of the better options, at least that I know of.

 

[DoctorEvo]

Thank you, that's actually really interesting. I'd always assumed that adding aero surfaces would just worsen the problem. I guess it's pry cause lateral movement, but resist rotation. Makes sense. I'm more interested in high altitude though tbh, and the thicker ropes is a good idea, but honestly something my club pry won't pursue because of the added weight and complexity... idk.

If you have the time, go ahead and look through that study. They mention that passive solutions (including the multiple rigging lines they cite as most effective for high altitudes) are generally lighter than active stabilization,

Out of curiosity, how much does your RCS system weigh? Also, what did you use for propellant? CO2?

And when you look at active, RCS is actually pry one of the better options, at least that I know of.

Depends what you mean by "better," I suppose. Cool factor? THE BEST, hands-down.

 

[Lt. Snakestrike]

If you have the time, go ahead and look through that study.

Already did.

Cool factor?

Honestly, I think that's part of the reason the club chose to use RCS.