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

Gargamel · 02-16-17, 01:29 AM

Quote:

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 · 02-16-17, 07:22 AM

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.

August · 02-16-17, 08:37 AM

Quote:

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 · 02-16-17, 01:25 PM

Quote:

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 · 02-17-17, 06:15 PM

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 · 02-17-17, 06:58 PM

Quote:

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.

Platapus · 02-18-17, 11:39 AM

Planet wants to cover the entire world once a day with 3m GSD Pan. Not a bad goal if they can find the customers.

02-17-17, 06:15 PM	#5
Platapus Fleet Admiral Join Date: Oct 2006 Posts: 19,386 Downloads: 63 Uploads: 0	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. __________________ abusus non tollit usum - A right should NOT be withheld from people on the basis that some tend to abuse that right.

02-18-17, 11:39 AM	#7
Platapus Fleet Admiral Join Date: Oct 2006 Posts: 19,386 Downloads: 63 Uploads: 0	Planet wants to cover the entire world once a day with 3m GSD Pan. Not a bad goal if they can find the customers. __________________ abusus non tollit usum - A right should NOT be withheld from people on the basis that some tend to abuse that right.

02-16-17, 07:22 AM	#2
Oberon Lucky Jack Join Date: Jul 2002 Posts: 25,976 Downloads: 61 Uploads: 20	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.