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Re: SpaceX News

Posted: Tue Jun 04, 2019 3:42 pm
by krenshala
At the end of their useful lives, the satellites will use their ion thrusters to crash back into the Earth’s atmosphere, burning up, and thus preventing them from becoming space debris.

Just one nit to pick - the sats won't use their ion thrusters to deorbit. To deorbit, they will stop using their ion thrusters for station-keeping, and let atmospheric drag deorbit them in a matter of weeks to months (depending on their specific altitude).

Re: SpaceX News

Posted: Tue Jun 04, 2019 10:44 pm
by Maui
Are you sure about that? I know I've seen conversation about how the Starlink sats will actively de-orbit... though I have to admit I can't find an actual source behind that conversation for the moment.

It doesn't make sense to me why you wouldn't. I imagine with an active de-orbit you could likely have some degree of confidence in hitting an ocean rather than land (current versions don't 100% disintegrate). Plus, even if you are even saving a couple of weeks, if you have the thrusters, why not?

Re: SpaceX News

Posted: Tue Jun 04, 2019 11:03 pm
by Skipjack
Maui wrote:Are you sure about that? I know I've seen conversation about how the Starlink sats will actively de-orbit... though I have to admit I can't find an actual source behind that conversation for the moment.

It doesn't make sense to me why you wouldn't. I imagine with an active de-orbit you could likely have some degree of confidence in hitting an ocean rather than land (current versions don't 100% disintegrate). Plus, even if you are even saving a couple of weeks, if you have the thrusters, why not?

I too have a vague memory that the passive de- orbit is only meant for those satellites that fail for some reason or another. The others will be actively de- orbited at the end of their lifetime.

Re: SpaceX News

Posted: Thu Jun 06, 2019 5:10 pm
by krenshala
Okay, now that you mention it, I think you're both right that passive deorbit was just a side benefit of the altitude, but not their actual plan. Still, its nice to know that even if they didn't actively deorbit the satellites, they will (relatively) rapidly fall out of the sky once they run out of fuel and/or stop functioning.

Re: SpaceX News

Posted: Fri Jun 07, 2019 4:54 pm
by Maui
Right. I think one of the reasons they are launched below their operational orbit it to help ensure any DOA satellites de-orbit that much faster.
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Re: SpaceX News

Posted: Fri Jun 07, 2019 7:07 pm
by kunkmiester
Read an article recently on Europe's launch systems. It talked about what I recall was like a decade of plans, but no mention at all of developing a reusable rocket in the Falcon vein. Blew my mind.

Re: SpaceX News

Posted: Sat Jun 08, 2019 3:06 am
by Skipjack
kunkmiester wrote:Read an article recently on Europe's launch systems. It talked about what I recall was like a decade of plans, but no mention at all of developing a reusable rocket in the Falcon vein. Blew my mind.

They do have plans for something like Falcon 9. First step is a "Grasshopper" like experimental rocket. Of course it is a joint European project, so the whole thing will move at a snail's pace. By the time they have their Grasshopper, SpaceX will have landed on Mars...

Re: SpaceX News

Posted: Mon Jun 10, 2019 4:30 pm
by JLawson
They do have plans for something like Falcon 9. First step is a "Grasshopper" like experimental rocket. Of course it is a joint European project, so the whole thing will move at a snail's pace. By the time they have their Grasshopper, SpaceX will have landed on Mars...


That's making the assumption that they actually WANT a space program, instead of a budget item that can be stretched out eternally but doesn't need results. Kind of like NASA and the SLS - as long as it never flies they're good. If it flies and fails, then they'll have to justify the money wasted in development, but they'll probably get more to work the kinks out. If it flies and succeeds, they're going to be forced to justify why it took so long and so much money, and why they don't have the next one in the pipeline to be ready for flight in 6 months. (Pulling out arbitrary time frame there.)

As long as they can delay, they're good.

Whereas Musk just keeps on going. It's remarkable what can happen once you've got one man basically deciding what's going to be done and on what schedule instead of an unaccountable committee, isn't it?

Re: SpaceX News

Posted: Fri Jun 14, 2019 5:23 pm
by Maui
It does appear they are now actively de-orbiting one of the Starlink satellites:
https://twitter.com/planet4589/status/1 ... 8001314816

Regarding ESA, they are actually now dipping their toes in a commercial launch provider program as well:
https://www.esa.int/Our_Activities/Spac ... n_services