Spies in the sky ... India launches 104 satellites on one rocket

[Mr Quatro]

This is more interesting than it looks ... 90 satellites only cost $10 million to launch in one launch.

https://www.nytimes.com/2017/02/15/w...cket.html?_r=0

Eighty-eight of the 104 satellites released on Wednesday were tiny, weighing about 10 pounds. Called Doves, they belong to Planet Labs, a private company based in San Francisco that sells data to governments and commercial entities, and they constituted the largest satellite constellation ever launched into space.

[Platapus]

Hardly spies in the sky when everyone knows about them.

They are called doves because they are released in orbit in flocks.

[Catfish]

[Oberon]

Someone is going to make a killing with space garbage collection one day.

[Skybird]

Why do I think of shotgun shells now...

[Gargamel]

Kessler Syndrome FTW!

[August]

Originally Posted by Oberon

Someone is going to make a killing with space garbage collection one day.

First they have to figure out how to catch things going thousands of miles per hour.

[Oberon]

Originally Posted by August

First they have to figure out how to catch things going thousands of miles per hour.

Well, the trick is to also go thousands of miles an hour, then get the object, slow down orbital velocity and then let go, and then return to orbital velocity while the object falls into the earths atmosphere and burns up.
The kicker is that you need a base to operate from, fuel to use, personnel rotation, all that logistical fun and games. The actual garbage collection is relatively straight forward (relative within the framework of doing stuff in space itself which is already not that simple) it's more the costs and logistics which mean that it hasn't been done yet.
Of course, as space tourism starts to be a thing, as soon as someones space-plane gets a hole ripped in it by part of a Soviet satellite from 1986 then clearing up space junk will suddenly become a more feasible mission.

[Gargamel]

Originally Posted by August

First they have to figure out how to catch things going thousands of miles per hour.

This they've done, with a variety of concepts. Usually it's been proposed by private industry, so they're looking to make money off the deal, which makes sense.

As most orbits are prograde of some sort, West to East, the closing speeds aren't as bad as you'd assume. A lot of the proposals are calling for large fishing net style of collection. Then they just close up the net with the junk inside of it.

The real kicker is collecting the returned items. If you just let them burn up in reentry, then there's no profit to be had. Building the infrastructure to reclaim the stuff is the problem. Give the nature of the process, it will usually not be a craft that can be easily controlled during reentry, the aerodynamic forces will send it wherever it feels like. So not only will you have difficulty getting to it, finding it and hoping it didn't land somewhere populated, or deep, is a major concern.

It will only become feasible when insitu (orbital) processing stations become practical, that way controlled reentry won't be as big of an issue.

[Oberon]

Heck, we catch something going thousands of miles an hour every time we go to the ISS which is travelling at 17,200mph. Been doing that sort of thing since Gemini VI and VII rendezvoused in 1965. It's usually a case of matching orbit, then increasing orbital velocity whilst maintaining a stable orbit (which involves thrusting at your apoapsis and periapsis) until you creep up on the object, then decrease your orbital speed until you match velocities, then thrust at the object and increase and decrease your speed to meet it.
It's a bloody hard thing to work out when you first time you try it but when you get your head around it, it's not too bad.

The kicker is having everything up there in order to resupply it all, once we get a cheap and reusable way to orbit then it will get a lot easier.

[Jimbuna]

Originally Posted by August

First they have to figure out how to catch things going thousands of miles per hour.

Hasn't that already been done?

http://www.imdb.com/title/tt0186566/

[August]

Originally Posted by Oberon

It's usually a case of matching orbit, then increasing orbital velocity whilst maintaining a stable orbit (which involves thrusting at your apoapsis and periapsis) until you creep up on the object, then decrease your orbital speed until you match velocities, then thrust at the object and increase and decrease your speed to meet it.
It's a bloody hard thing to work out when you first time you try it but when you get your head around it, it's not too bad.

The kicker is having everything up there in order to resupply it all, once we get a cheap and reusable way to orbit then it will get a lot easier.

I have no problem visualizing what needs to be done. No, the real kicker is trying to do it for every nut, bolt and tiny scrap of metal that is flying around up there.

[Oberon]

Originally Posted by August

I have no problem visualizing what needs to be done. No, the real kicker is trying to do it for every nut, bolt and tiny scrap of metal that is flying around up there.

Yup, that is going to take a very long time and a very detailed radar and laser scanning system in order to find all of them. There is talk, as Gargamel has said, of using a net system in order to scoop the stuff up, so that might actually help if a very large net was sent on the right orbit and essentially trawled it clean. That's certainly one option and probably a lot quicker and easier than individually sweeping up each nut and bolt.

[Platapus]

There have been some experiments using ground based lasers to clear out the larger stuff, but as August pointed out, the big stuff we know about and can avoid, its the small stuff that can really ruin your orbital day.

[Tango589]

Originally Posted by Platapus

There have been some experiments using ground based lasers to clear out the larger stuff, but as August pointed out, the big stuff we know about and can avoid, its the small stuff that can really ruin your orbital day.

Yep, it would be no fun getting clouted in the back of the head by that toolbag that was lost in orbit, unless it's already fallen back to earth and frazzled up.