MO-76 (50dollarsat) was licensed by the FCC and had to submit a debri mitigation plan. 50dollarsat was approximately 2" x 2" x 3" and most certainly is being tracked by radar without retro reflectors. You can find all about 50dollarsat at 50dollarsat.info with links to schematics, pictures and descriptions. One of the things that reduces the time in orbit is the very low mass of 210 grams. That in addition to Kapton sail brakes on the antenna's to increase drag made the deorbit prediction to be less than 10 years. The "too small" argument does not seem to hold water in my opinion. However, that doesn't mean they should have violated the law.
Howie AB2S
________________________________ From: AMSAT-BB amsat-bb-bounces@amsat.org on behalf of Zach Leffke zleffke@vt.edu Sent: Tuesday, March 13, 2018 5:13 PM To: amsat-bb@amsat.org Subject: Re: [amsat-bb] FCC and Satellite Size
I've been following this as well.....and am confused about one or two things...maybe someone can enlighten me?
This article has links to the actual exchanges between the company and the FCC for folks that are interested in the 'source material': https://nam01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fspectrum.i...
Seems the problem was that they were too small (0.25U) for the ground based space situational awareness tracking network to reliably track them for the purpose of collision avoidance and prediction for other spacecraft operators. They mentioned the addition of retro-reflectors to aid in ground based tracking by increasing their radar cross section, but FCC said this wasn't good enough. That was the grounds for rejection from the FCC, too small to be tracked.
To be clear, the ACTUAL problem was that despite the fact the FCC turned them down, it appears they worked the system to launch anyway, same ride as AO-92 (so roughly the same orbit, though obviously there has been separation over time)! Not good.
So putting aside the apparent disregard for the FCC...........why did they get rejected in the first place? FCC said they were too small....but............
I'm pretty sure the 0.25U form factor is something that Bob Twiggs (of cubesat specification fame, as well as had a hand in MO-76) is pushing. I forget the name they came up with for the 0.25U form factor, but they had a new one (different I think than pocketQub form factor, like MO-76). How then did MO-76 (aka Eagle-2, aka $50Sat) get up? It is a 'pocket cube' sized spacecraft (roughly maybe 1/3 the size of a 1U cubesat). Also, how did KickSat get approval with all of its little roughly 1" by 1" deployable 'Sprites?' I'm pretty sure both MO-76 and Kicksat were approved by the FCC. Kicksat never deployed its Sprites so no 'tracking data' for that, but MO-76 had reliable TLEs throughout its life (and still does, most recent TLE epoch from a day or two ago on celestrak). Also, if they are too small to reliably track, then how are their TLEs getting updated reliably (their called SpaceBEEs for those interested, index like APRS SSID, so SpaceBEE-1, SpaceBEE-2, etc. and their are four of them total)? Satflare and N2YO are showing them (though couldn't find them on Celestrak....).
Did the Amateur Radio nature of MO-76 and Kicksat factor into their approval decision (the SpaceBEEs were an experimental filing and not in the Amateur Satellite Service)? Maybe that was the trick? Amateur Radio Licensing is more of a notification process to the FCC (and coordination with IARU), where as the Swarm Technology folks were straight up applying for a new license under experimental rules? Both routes have to submit information according to what Paul mentioned, but since the other two were 'already licensed' there was nothing for the FCC to actually 'grant' ? (this is pure speculation, but I still wonder....)
Finally, Kicksat was deployed from ISS and the 'mothership' was a 3U (certainly trackable). Maybe since the sprite deployment was planned for after the deployment from the ISS at lower altitudes they didn't really care about tracking since they were going to burn up in a relatively short time anyway. Also, the 'cloud of sprites' deployed from kicksat would have been all around the 3U, so maybe that was sufficient for tracking purposes? Still doesn't answer the MO-76 question though........
Interesting topic to see how this plays out........Already relevant to this group with respect to MO-76, and potentially relevant for future AMSAT missions if launch costs can be further reduced below a 1U form factor.......
I ask because we are interested in the smaller form factor stuff here at VT, so this is pretty important if the minimum size is dictated by regulation and not technology. Seems to me that there is a 'gray area' in terms of what can and can't be tracked (maybe intentional to not reveal too much of the SSA capability?). From a regulatory perspective maybe MO-76 and KickSat 'slipped through' because they were older launches and the FCC wasn't prepared for something that small and has since changed its process to include asking the SSA folks before approving?
-Zach
Research Associate Aerospace Systems Lab Ted & Karyn Hume Center for National Security & Technology Virginia Polytechnic Institute & State University Work Phone: 540-231-4174 Cell Phone: 540-808-6305
On 3/13/2018 5:04 PM, Paul Stoetzer wrote:
The denied application was for transmissions in the 137 MHz Space Operations Service band.
The orbits are 505 km x 490 km, inclined 97.55 degrees. They are cataloged by Space-Track (see objects 43139 - 43142), indicating at least the ability to track them at some points.
73,
Paul, N8HM
On Tue, Mar 13, 2018 at 4:53 PM, Joe N3XLS via AMSAT-BB amsat-bb@amsat.org wrote:
Are these things in a safe orbit? What frequencies do they use? I would hate for one if these .25U objects to hit one of our sats and completely wipe us out. It seems from the two articles i read on this incident a bunch of people messed up. Including swarm not understanding the situation. -------- Original message --------From: radiomb radiomb@bellsouth.net Date: 3/13/18 3:51 PM (GMT-05:00) To: Amsat BB amsat-bb@amsat.org Subject: [amsat-bb] FCC and Satellite Size Just saw this article. The FCC is the controlling agency for the size of a satellite? Not NASA or another agency of the government? Guess that is part of the process that AMSAT has to go thru to get a bird approved. Don't launch these tiny satellites, the FCC said. They're apparently in space anyway
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73 Mike K4MIA
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_______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://nam01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.amsat.o...