Submitted by NinjaMoreLikeANonja t3_11xyfzt in IAmA

Gimme dat proooooooooof!

I am Marco, Chief Engineer of SBUDNIC ( The satellite is a 3U cubesat built at Brown University over the course of a year and a half by a team of students, myself included. The whole thing costs about $7500 USD if you were to rebuild it from scratch, uses a novel spring-loaded drag sail to deorbit itself (no space junk!), runs off an Arduino Nano, and is powered by 48 AA lithium batteries. SBUDNIC was launched as part of the SpaceX Transporter 5 mission out of SLC40 on Cape Canveral in late May of 2022.

We just released data that shows that our drag system is working as designed! It's been covered by, PopSci, and seems to be pretty popular here on Reddit too.

Our hope is that this satellite demonstrates that responsible deorbiting is possible without significant cost or mass penalty.

Ask me anything!



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CurlSagan t1_jd5gyrr wrote

I just want to say that "SBUDNIC" is a fantastic name. Have you considered making a NASA-style arm patch for the mission? I'm picturing an orbiting potato.


Pielord775 t1_jd5e82c wrote

How long do you think it would take for companies to adopt this method? And what persuaded y’all start the project?


NinjaMoreLikeANonja OP t1_jd5exo7 wrote

We are not the first people to do a drag sail by any means, so companies are already using this tech. The difference is that we did it faster and WAYYYYY cheaper than it's been done before, especially at the scale of a cubesat.

Our aerospace professor Rick Fleeter had access to a launch slot so 4 of us decided to spin up the project into something big. It grew from there into a team of 65+ plus students and engineers from across the world. All the engineering and fab was done at Brown by students; the multinational part of the team was our launch partner, D-Orbit, who provided a carrier satellite for the ride up to space.


Doomenor t1_jd5eh2i wrote

How does a sail work in space where there is no atmosphere? Why a cube and not a sphere?


NinjaMoreLikeANonja OP t1_jd5fe1c wrote

There is actually atmosphere in space! The atmosphere never really ends, it just kinda slowly gets less and less dense. Technically, there's Earth atmosphere on the Moon, but it's just suuuuuuuuuper duuuuuuper basically-not-really-there. Also, the Sun spews hot space gasses at us constantly so there's drag from that too.

At 550km where SBUDNIC was initially deployed, there's very very little but- over the course of thousands of orbits- the drag adds up! It takes a long time.


NinjaMoreLikeANonja OP t1_jd5fmii wrote

Also, cube because cubes pack nicely. Small satellites are generally all described in matters of size as a multiple of 1U, which is a 10cm cube. So a 3U, like SBUDNIC, is 30x10x10cm.


ITinMN t1_jd5ij7b wrote

Sputnik, right?


NinjaMoreLikeANonja OP t1_jd5mwxf wrote


And then Russia invaded Ukraine about 4 months after we filed the legal paperwork cementing the name in place.

The principle stays the same though- faster, cheaper, proof of concept.


ITinMN t1_jd6c88s wrote

The best laid schemes o' mice an' men
Gang aft a-gley

Best o' luck te ye'


obnoxygen t1_jd5l990 wrote

No Ham Radio?


NinjaMoreLikeANonja OP t1_jd5nrcw wrote

Yes! There’s a ham radio on SBUDNIC. We tapped into the TinyGS network. Our specific module was the RFM96. This part of the mission failed. We also built two wide angle cameras into the front end of SBUDNIC, with the intent that we would transmit a couple potato vision quality images down from space over ham band. We tested the ever-living daylights out of that subsystem and- for reasons that will forever remain unknown- it just failed to work on orbit. We never actually heard a radio ping of any kind from SBUDNIC.

That being said, we know the satellite was alive- at least in the beginning- otherwise the sails would not have deployed.

We optimized for satellite lifetime rather than broadcast frequency. It’s totally possible that we were just never in the right place at the right time to catch SBUDNIC’s radio blast. It was set up to transmit every 10 minutes, for about a minute. The TinyGS network is pretty great, however we were broadcasting at 50mW so it was a VERY quiet signal even in the best of times. It’s not impossible- it’s been done before by other satellites- but it’s certainly challenging.


obnoxygen t1_jd7iryj wrote

> TinyGS network

Uh-oh... into the rabbit hole we go...

(thanks for mentioning what might be an interesting project)


singalongthetower2 t1_jdbatu7 wrote

If you had travel back in time, would you still use the RFM96 or used another module?


NinjaMoreLikeANonja OP t1_jdc9e2g wrote

Hindsight is 20/20, and engineering hindsight is hyperspectral 20/20 so…

Honestly, there are not that many ham radio modules for Arduino. We were also supply chain limited (this was in the midst of the COVID parts shortages) and the RFM96 was usually in stock.

I just spoke with SBUDNIC’s radio engineer last night and we talked a bit about this because we are in the midst of creating a more formal conference paper that details the project. His feeling is that the board is likely fine, and that we just made some shit assumptions about duty cycle and link margin and the like when we were finalizing transmission protocols. I agree with him.

So yes- I would use it again.


singalongthetower2 t1_jd6mqou wrote

What led to this initial drive to start/make this? And the benefits for using this technology?


NinjaMoreLikeANonja OP t1_jd7cy3w wrote

A bunch of us took a class called ENGN1760: The Design of Space Systems, taught by Rick Fleeter. Rick is a true spacelord engineer through and through (among his many achievements: he invented and launched a precursor system to GPS) so he’s- as you’d imagine- pretty well connected. He came into a launch opportunity and passed it on to the class.

At the end of the semester, four of us decided to keep going and build the project into what it is today. We grew the team to ~40 folks at Brown, and then another ~25 folks elsewhere in the world who were consulting/helping out/working with our launch provider. No one got paid- everyone did this out of the love of the game. Pretty amazing.

We aren’t the first folks to put a drag sail on a satellite but we are likely the first folks to do it as cheaply and quickly as we did it. Our hope is that the satellite demonstrates that deorbiting is not expensive, from both a financial and mass perspective. The system cost maybe $150 and weighs ~$250 grams. In the space world, that’s pretty damn good. About $140 of that build cost was the Kapton film- that stuff is expensive!- so if someone were to find a more affordable space-safe material, the system could be made far more cheaply. I would love to see that.


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WingedCat t1_je6n9sc wrote

Do you have any plans to commercialize this system, so others who want to deorbit can buy your solution rather than having to redevelop it?