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> Swarm applied for an FCC license, but was denied on concerns that its spacecraft, being "smaller than 10 cm in one of their three dimensions," couldn't be rel

> Swarm applied for an FCC license, but was denied on concerns that its spacecraft, being "smaller than 10 cm in one of their three dimensions," couldn't be reliably tracked by the Air Force's Space Surveillance Network. And what is the concern around tracking them, inability to divert a spacecraft or satellite that might collide with a swarm of small objects?

piker 8y ago
Yes, but not only a swarm, even just a single satellite is a tiny missile that is otherwise invisible in LEO.
- everdev 8y ago
  Then yeah, that seems pretty irresponsible to put other people's property in danger and potentially lives if they're within distance of the ISS.
- outworlder 8y ago
  And what is it made of? These satellites are tiny. Unless they are made of more exotic materials, they will not survive reentry.
  - DrScump 8y ago
    they will not survive reentry That's like saying that stray bullets aren't a problem because they'll stop the first time they hit anything.
  - stephengillie 8y ago
    Just what we need - more heavy metals polluting our air, forming oxides with members of the Actinide and Lanthanide groups from their vaporized processors.
cbanek 8y ago
Most spacecraft/satellites don't have onboard radar or other local scanning equipment, and "diverting" a spacecraft is actually a pretty complicated thing. This would involve multiple delta-v (using thrusters), both to avoid the object and then go back into their normal orbit. That could eliminate years of useful lifetime of a satellite, because those thrusters are usually used just for stationkeeping. Also, whatever orbit they are in is usually related to what the satellite is doing, so it might affect performance/reception/scanning/etc. Just like the movie Gravity, if there was an explosion in space and you had a lot of small objects floating around in a cloud you can't detect, that could snowball into destroying more things in orbit, making the problem even worse. Right now there's no way I know of to clean up space junk in orbit other than waiting for it to burn up, which could take years or tens of years. https://en.wikipedia.org/wiki/Orbital_station-keeping https://en.wikipedia.org/wiki/Orbital_station-keeping
- akira2501 8y ago
  > that could snowball into destroying more things in orbit It even has a name: https://en.wikipedia.org/wiki/Kessler_syndrome https://en.wikipedia.org/wiki/Kessler_syndrome
- deleted 8y ago
  [deleted]
- mirashii 8y ago
  I think you heavily overstate the difficulty and cost of diverting a spacecraft, especially in the case of cubesats, which in general do not have any propulsion systems to do the delta-v manuevers you state. For collision avoidance for cubesats, realistically you just change the drag profile to bring the spacecraft into a higher or lower orbit. While this can in some cases have an impact on lifetime, they're not generally going to be manuevers away from their existing orbit enough to change performance or reception characteristics as the new orbit is always going to be an orbit that the spacecraft would be expected to hit anyways. Additionally, as other comments have alluded to, part of the FCC requirements that these spacecraft have to meet is a maximum deorbit time, which is (I believe) 25 years. For satellites as low as these ones were, that period will be lower. I'm all for the FCC throwing the book at this company, but just want to make sure we don't have misconceptions as a community about what or why these things are regulated and how they work.
ceph_ 8y ago
Space debris is a massive problem that is only getting worse. [1] These objects aren't just floating up there, they're travelling at tens of thousands of miles per hour. If they can't be tracked, they can't be avoided. [1] https://youtu.be/HVov8o9x0yI https://youtu.be/HVov8o9x0yI
- randyrand 8y ago
  It can be tracked, just not 100% of the time. But here's the thing. Momentum. If you've tracked it once, you know its location for many months to come.
  - JumpCrisscross 8y ago
    > If you've tracked it once, you know its location for many months to come Not in low-earth orbit. Look at this graph of the ISS's altitude over time [1]. Atmospheric drag makes orbital dynamics too complicated for long-term predictions. Add in station-keeping [2] jitter, and one has a necessity for reliable tracking. [1] http://images.huffingtonpost.com/2014-05-17-ISSaltitude.png http://images.huffingtonpost.com/2014-05-17-ISSaltitude.png [2] https://en.wikipedia.org/wiki/Orbital_station-keeping https://en.wikipedia.org/wiki/Orbital_station-keeping
    - pathseeker 8y ago
      In low-earth orbit space debris will just fall into the atmosphere pretty quickly because they have no maintenance burns.
      - CapitalistCartr 8y ago
        It often takes decades. There is still debris from the 1960s in LEO, which has a lot. Five satellite collisions have complicated things. I suggest this Wikipedia article: https://en.m.wikipedia.org/wiki/Space_debris https://en.m.wikipedia.org/wiki/Space_debris "Below 2,000 km (1,200 mi) Earth-altitude, debris are denser than meteoroids; most are dust from solid rocket motors, surface erosion debris like paint flakes, and frozen coolant from RORSAT nuclear-powered satellites." And the journal Orbital Debris Quarterly https://orbitaldebris.jsc.nasa.gov/quarterly-news/newsletter.html https://orbitaldebris.jsc.nasa.gov/quarterly-news/newsletter...
gnode 8y ago
Maybe this is something which cheaper space-launch could solve. If it were economical to send maintenance robots to fix dead satellites, then perhaps these tiny satellites could be allowed to self-track (using GPS). In the event that the satellite fails it could be repaired / collected / de-orbited before its orbit deviates too far from nominal.
- djrogers 8y ago
  > perhaps these tiny satellites could be allowed to self-track (using GPS) Not so sure GPS would work well up in space, given that the signals are aimed down at the planet's surface.
  - baobrien 8y ago
    GPS Satellites are in MEO, so AFAIK, it's possible to get a GPS track in LEO -- assuming the receiver isn't artificially altitude and speed capped.
    - cbanek 8y ago
      You can get GPS in LEO, but there are altitude and speed limits on non-military applications / chips. "In GPS technology, the term "COCOM Limits" also refers to a limit placed on GPS tracking devices that disables tracking when the device calculates that it is moving faster than 1,000 knots (1,900 km/h; 1,200 mph) at an altitude higher than 18,000 m (59,000 ft).[2] This was intended to prevent the use of GPS in intercontinental ballistic missile-like applications. Some manufacturers apply this limit only when both speed and altitude limits are reached, while other manufacturers disable tracking when either limit is reached. In the latter case, this causes some devices to refuse to operate in very high altitude balloons.[3]" https://en.wikipedia.org/wiki/Coordinating_Committee_for_Multilateral_Export_Controls https://en.wikipedia.org/wiki/Coordinating_Committee_for_Mul...
  - mirashii 8y ago
    For what it's worth, GPS does work, and can indeed work very well. Applications like GNSS-RO have been done on research and commercial LEO satellites and use GPS to get orbit position estimates down to 10s of centimeters.

piker 8y ago

Yes, but not only a swarm, even just a single satellite is a tiny missile that is otherwise invisible in LEO.

everdev 8y ago
Then yeah, that seems pretty irresponsible to put other people's property in danger and potentially lives if they're within distance of the ISS.
outworlder 8y ago
And what is it made of? These satellites are tiny. Unless they are made of more exotic materials, they will not survive reentry.
- DrScump 8y ago
  they will not survive reentry That's like saying that stray bullets aren't a problem because they'll stop the first time they hit anything.
- stephengillie 8y ago
  Just what we need - more heavy metals polluting our air, forming oxides with members of the Actinide and Lanthanide groups from their vaporized processors.

cbanek 8y ago

Most spacecraft/satellites don't have onboard radar or other local scanning equipment, and "diverting" a spacecraft is actually a pretty complicated thing. This would involve multiple delta-v (using thrusters), both to avoid the object and then go back into their normal orbit. That could eliminate years of useful lifetime of a satellite, because those thrusters are usually used just for stationkeeping. Also, whatever orbit they are in is usually related to what the satellite is doing, so it might affect performance/reception/scanning/etc. Just like the movie Gravity, if there was an explosion in space and you had a lot of small objects floating around in a cloud you can't detect, that could snowball into destroying more things in orbit, making the problem even worse. Right now there's no way I know of to clean up space junk in orbit other than waiting for it to burn up, which could take years or tens of years. https://en.wikipedia.org/wiki/Orbital_station-keeping https://en.wikipedia.org/wiki/Orbital_station-keeping

akira2501 8y ago
> that could snowball into destroying more things in orbit It even has a name: https://en.wikipedia.org/wiki/Kessler_syndrome https://en.wikipedia.org/wiki/Kessler_syndrome
deleted 8y ago
[deleted]
mirashii 8y ago
I think you heavily overstate the difficulty and cost of diverting a spacecraft, especially in the case of cubesats, which in general do not have any propulsion systems to do the delta-v manuevers you state. For collision avoidance for cubesats, realistically you just change the drag profile to bring the spacecraft into a higher or lower orbit. While this can in some cases have an impact on lifetime, they're not generally going to be manuevers away from their existing orbit enough to change performance or reception characteristics as the new orbit is always going to be an orbit that the spacecraft would be expected to hit anyways. Additionally, as other comments have alluded to, part of the FCC requirements that these spacecraft have to meet is a maximum deorbit time, which is (I believe) 25 years. For satellites as low as these ones were, that period will be lower. I'm all for the FCC throwing the book at this company, but just want to make sure we don't have misconceptions as a community about what or why these things are regulated and how they work.

ceph_ 8y ago

Space debris is a massive problem that is only getting worse. [1] These objects aren't just floating up there, they're travelling at tens of thousands of miles per hour. If they can't be tracked, they can't be avoided. [1] https://youtu.be/HVov8o9x0yI https://youtu.be/HVov8o9x0yI

randyrand 8y ago
It can be tracked, just not 100% of the time. But here's the thing. Momentum. If you've tracked it once, you know its location for many months to come.
- JumpCrisscross 8y ago
  > If you've tracked it once, you know its location for many months to come Not in low-earth orbit. Look at this graph of the ISS's altitude over time [1]. Atmospheric drag makes orbital dynamics too complicated for long-term predictions. Add in station-keeping [2] jitter, and one has a necessity for reliable tracking. [1] http://images.huffingtonpost.com/2014-05-17-ISSaltitude.png http://images.huffingtonpost.com/2014-05-17-ISSaltitude.png [2] https://en.wikipedia.org/wiki/Orbital_station-keeping https://en.wikipedia.org/wiki/Orbital_station-keeping
  - pathseeker 8y ago
    In low-earth orbit space debris will just fall into the atmosphere pretty quickly because they have no maintenance burns.
    - CapitalistCartr 8y ago
      It often takes decades. There is still debris from the 1960s in LEO, which has a lot. Five satellite collisions have complicated things. I suggest this Wikipedia article: https://en.m.wikipedia.org/wiki/Space_debris https://en.m.wikipedia.org/wiki/Space_debris "Below 2,000 km (1,200 mi) Earth-altitude, debris are denser than meteoroids; most are dust from solid rocket motors, surface erosion debris like paint flakes, and frozen coolant from RORSAT nuclear-powered satellites." And the journal Orbital Debris Quarterly https://orbitaldebris.jsc.nasa.gov/quarterly-news/newsletter.html https://orbitaldebris.jsc.nasa.gov/quarterly-news/newsletter...

gnode 8y ago

Maybe this is something which cheaper space-launch could solve. If it were economical to send maintenance robots to fix dead satellites, then perhaps these tiny satellites could be allowed to self-track (using GPS). In the event that the satellite fails it could be repaired / collected / de-orbited before its orbit deviates too far from nominal.

djrogers 8y ago
> perhaps these tiny satellites could be allowed to self-track (using GPS) Not so sure GPS would work well up in space, given that the signals are aimed down at the planet's surface.
- baobrien 8y ago
  GPS Satellites are in MEO, so AFAIK, it's possible to get a GPS track in LEO -- assuming the receiver isn't artificially altitude and speed capped.
  - cbanek 8y ago
    You can get GPS in LEO, but there are altitude and speed limits on non-military applications / chips. "In GPS technology, the term "COCOM Limits" also refers to a limit placed on GPS tracking devices that disables tracking when the device calculates that it is moving faster than 1,000 knots (1,900 km/h; 1,200 mph) at an altitude higher than 18,000 m (59,000 ft).[2] This was intended to prevent the use of GPS in intercontinental ballistic missile-like applications. Some manufacturers apply this limit only when both speed and altitude limits are reached, while other manufacturers disable tracking when either limit is reached. In the latter case, this causes some devices to refuse to operate in very high altitude balloons.[3]" https://en.wikipedia.org/wiki/Coordinating_Committee_for_Multilateral_Export_Controls https://en.wikipedia.org/wiki/Coordinating_Committee_for_Mul...
- mirashii 8y ago
  For what it's worth, GPS does work, and can indeed work very well. Applications like GNSS-RO have been done on research and commercial LEO satellites and use GPS to get orbit position estimates down to 10s of centimeters.