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FCC Approves 5 Year Satellite Deorbiting Rule

payloadspace.com

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Re: FCC Approves 5 Year Satellite Deorbiting Rule

#71

Post by Retric »

mikeyouse wrote: post #61
Retric wrote: post #59

Earlier quoted context omitted.

Huge constellations with stable orbits under active control are irrelevant. It’s really the a pair of uncontrolled satellites colliding that’s a meaningful risk, and that risk grows exponentially with age. To the point where the difference between 1 day and 1 year is effectively meaningless while the difference between 5 years and 50 years is huge.

If we're launching 15k satellites per year as some people expect, the difference between 1 day deorbit and 5 years deorbit is something like 75,000 satellites.

If the risk of collisions in both scenarios is sub 0.0001%, is it a meaningful difference? Very quickly the risk is dominated by being launched into the wrong orbit.

Re: FCC Approves 5 Year Satellite Deorbiting Rule

#72

Post by s1artibartfast »

mikeyouse wrote: post #62
bisby wrote: post #54

Earlier quoted context omitted.

The rule is 5 years. You've given 2 examples under 5 years. If everything is going to re-enter within 5 years without boosting then your point is moot, because even in your "massively more collision risky" example, it still abides by the rules. If something was going to deorbit within 1 minute, or was going to deorbit within 4 years, 6 months... It doesn't matter to the creator, because they don't have to change thei…

Just responding to a comment that said "If deorbiting in years is sufficient, the difference in time is not relevant" where it's obviously relevant.. this doesn't seem remotely controversial.

Let me put this another way, if I use my computer to send emails, it doesn't matter to me if my ping is 10 milliseconds or 10 femtoseconds.

One time is 10^12 times longer, but the difference does not matter to me. My emails are still sent and received faster than I can possibly perceived.

Re: FCC Approves 5 Year Satellite Deorbiting Rule

#73

Post by Eleison23 »

One day we will need to pass laws against celebratory satellite launches on holidays and the urban microphone networks will be calibrated to detect heavy-lift launches by gangstas. New nations will enshrine the right to launch satellites in their constitutions. Elementary schools will go on lockdown when a student is discovered to have built a satellite and fuelled their boosters.

Re: FCC Approves 5 Year Satellite Deorbiting Rule

#74

Post by hahajk »

ntrz wrote: post #67
hinkley wrote: post #63

Earlier quoted context omitted.

In this case it's policy reflecting Little's Law: population = arrival rate X duration of visit If suddenly someone wants to launch twice as many satellites, you either have to reduce tenancy or accept a higher population in the system. If you have a policy that's at most 25 years and a lot of satellites de-orbit in say 15 years on average, you can still triple your launches by pulling that down to 5. I am worried th…

The article says "5 years after completing their mission", not 5 years after launch.

time to assign 25 year missions to satellites built to last 10 years!

Re: FCC Approves 5 Year Satellite Deorbiting Rule

#75

Post by jessaustin »

hinkley wrote: post #65
rzimmerman wrote: post #12

I think this is generally a good thing to do, with some caveats that I hope the FCC considers. For most satellites below ~450km, this is really a non-issue. Atmospheric drag will generally be sufficient to deorbit the satellite in a few years. For big Earth-observing constellations, Starlink and friends, and many small missions, this doesn't change anything. Debris don't really accumulate dangerously in this zone and…

How high can the debris loft after a particularly nasty collision? Two satellites hitting at an acute angle should produce a cone of debris in front of them, of which about a third deorbits and a third goes up into a higher orbit that's an average of the two. Two satellites that hit at an obtuse angle, well, they pancake and produce a donut of debris. The stuff headed straight up is on a parabolic orbit that will hit…

Angular momentum is subject to a conservation law.

Re: FCC Approves 5 Year Satellite Deorbiting Rule

#76

Post by gpm »

danieldbird wrote: post #68

I know how small the debris is relative to the earth. But the sheer number. Would that have any effect on the sun reaching earth and it’s heating / cooling?

No.

To have an effect you need to launch multiple orders of magnitude more mass than we have, and that mass would need to be optimized towards having as large as an effect as possible by being very very thin film positioned so that it is consistently between earth and the sun (or you could add on a few more orders of magnitude).

You can look at proposal for doing this intentionally to get a sense for the scale: https://en.wikipedia.org/wiki/Space_sunshade

Re: FCC Approves 5 Year Satellite Deorbiting Rule

#78

Post by ultra_nick »

danieldbird wrote: post #68

I know how small the debris is relative to the earth. But the sheer number. Would that have any effect on the sun reaching earth and it’s heating / cooling?

No, that's like trying to cool your house with a pinch of dust.

Bus = 0.0002 km²

Earth = 510.1 million km²

(Earth / Bus) / 100 = 25,000,000,000 bus sized satellites needed to cover 1% of the sky.

Re: FCC Approves 5 Year Satellite Deorbiting Rule

#79

Post by xani_ »

MichaelCollins wrote: post #7
pessimizer wrote: post #6

Earlier quoted context omitted.

If rules didn't cause inconvenience to someone, they wouldn't have to be written.

I was thinking more along the line of the new rule giving another commercial advantage to SpaceX. Starlink will be effected, their satellites already deorbit faster than 5 years. But many other satellite operators will have to launch more frequently, and SpaceX is positioned to meet that growing demand.

> But many other satellite operators will have to launch more frequently, and SpaceX is positioned to meet that growing demand.

Read the article. It's about deorbiting after mission is finished.

If you have enough fuel on board you're free to keep your satellite for 50 years on the orbit. You just have to deorbit it within 5 after you stopped using it.

Re: FCC Approves 5 Year Satellite Deorbiting Rule

#80

Post by xani_ »

teawrecks wrote: post #9
MichaelCollins wrote: post #2

> The rule shortens the time required for satellite operators to deorbit LEO satellites to no more than 5 years after completing their mission, from 25 years. De-orbiting faster means reserving more propellant for the final de-orbit burn. Since the lifespan of satellites is already generally determined by how much propellant they have, this new rule effectively reduces the lifespan of any satellite high enough to req…

I'm no rocket scientist, but could there be a service which knocks satellites out of orbit for people? I wonder how cost effective such a service could get. Could one mission knock 10 satellites out of orbit?

It would be most likely far more expensive than just adding few kg to your payload to allow for faster deorbit.
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