4 ms·

It’s actually quite easy for a satellite to defend itself. It just needs delta v or a lot of energy for a directed energy weapon. It takes a big rocket and lo

by lumost 4y ago

It’s actually quite easy for a satellite to defend itself. It just needs delta v or a lot of energy for a directed energy weapon. It takes a big rocket and lots of time to hit something in geosynchronous orbit. If the satellite has been refueled, it’s delta v capability would dwarf any potential impactors. Otherwise it’s going to be 30+ minutes for a potential impactor to reach the satellite, why not shoot a laser at it for that time period?

Retric 4y ago
Because your adversary could send a bunch of tiny objects in the opposite orbit that impact at around Mach 40. You can for example destroy every single satellite in geostationary orbit by launching 1 payload of junk going the wrong way. Worse this isn't recoverable geostationary orbit is simply useless on the scale of hundreds of years. Dodging with delta V becomes a continuous problem you can at best simulate geostationary orbit with constant acceleration. Geosyncronus is a slightly wider range of orbits, but not enough to be safe.. Laser weapons in space are again a fun sci-fi idea, but hardly practical.
- lumost 4y ago
  1) The object you launch going the wrong way will not have substantial delta-v capability. There are many slots across a wide range of orbits. A hypothetical defensive satellite would only need a few dozen meters/second delta-v to avoid the object. With in-orbit refueling, the orbital satellite has the advantage over a promptly launched weapon. 2) Laser weapons are available for shipborne use today. Airborne defensive lazers targeting Air to Air missiles are currently undergoing tests as part of the 6th generation fighter program. The "sci-fi" you are alluding to is now just a question of power output and weight. If the goal is to disable command and control of a potential impactor satelite over the course of ~30 minutes - the power output requirement needn't be more than a few KW. With a few dozen KW ablative heating of the impactor could push it off course. The key enabling technology is in cheap, re-usable, heavy-lift. Given this, it will always be possible to put a satellite in orbit with more delta-v capability than any mobile and disposable satellite weapon.
  - Retric 4y ago
    1) The point isn't to launch one object the point is to launch a shotgun blast of 10 million objects each of which can destroy your satellite. You need km/s delta V to deal with this kind of attack. 2) Lasers are much easier in atmosphere for a huge range of reasons. If something is approaching you at mach 4 you get 1/10th the time to deal with the situation as much 40. Further in space fragments are deadly, a 2.5 gram object at mach 40 has the about kenetic energy as 1 kg object at match 2. Blowing up the rocket aimed for your satellite might not actually help. Anyway there are vastly better orbital weapons than I just described, the point is any nation that can get mass into orbit can absolutely anailate orbital infrastructure.
    - Retric 4y ago
      * make that 10x not 1/10th Edited without thinking.
defrost 4y ago
Geosynchronous orbits are way out from the planet and costly, in many ways the "space game" of earth communications, earth monitoring, comms for earth wars has changed. Constellations of thousands of satellites in near earth obits, precessing for coverage, in near ellipitic orbits for relatively low cost repositioning over tagets of interest, and "not real satellites" - HAPS and blimps are changing the dynamics. Cheaper to launch, greater in number, and more easily moved about and|or replaced.

by lumost 4y ago

Retric 4y ago

Because your adversary could send a bunch of tiny objects in the opposite orbit that impact at around Mach 40. You can for example destroy every single satellite in geostationary orbit by launching 1 payload of junk going the wrong way. Worse this isn't recoverable geostationary orbit is simply useless on the scale of hundreds of years. Dodging with delta V becomes a continuous problem you can at best simulate geostationary orbit with constant acceleration. Geosyncronus is a slightly wider range of orbits, but not enough to be safe.. Laser weapons in space are again a fun sci-fi idea, but hardly practical.

lumost 4y ago
1) The object you launch going the wrong way will not have substantial delta-v capability. There are many slots across a wide range of orbits. A hypothetical defensive satellite would only need a few dozen meters/second delta-v to avoid the object. With in-orbit refueling, the orbital satellite has the advantage over a promptly launched weapon. 2) Laser weapons are available for shipborne use today. Airborne defensive lazers targeting Air to Air missiles are currently undergoing tests as part of the 6th generation fighter program. The "sci-fi" you are alluding to is now just a question of power output and weight. If the goal is to disable command and control of a potential impactor satelite over the course of ~30 minutes - the power output requirement needn't be more than a few KW. With a few dozen KW ablative heating of the impactor could push it off course. The key enabling technology is in cheap, re-usable, heavy-lift. Given this, it will always be possible to put a satellite in orbit with more delta-v capability than any mobile and disposable satellite weapon.
- Retric 4y ago
  1) The point isn't to launch one object the point is to launch a shotgun blast of 10 million objects each of which can destroy your satellite. You need km/s delta V to deal with this kind of attack. 2) Lasers are much easier in atmosphere for a huge range of reasons. If something is approaching you at mach 4 you get 1/10th the time to deal with the situation as much 40. Further in space fragments are deadly, a 2.5 gram object at mach 40 has the about kenetic energy as 1 kg object at match 2. Blowing up the rocket aimed for your satellite might not actually help. Anyway there are vastly better orbital weapons than I just described, the point is any nation that can get mass into orbit can absolutely anailate orbital infrastructure.
  - Retric 4y ago
    * make that 10x not 1/10th Edited without thinking.

defrost 4y ago

Geosynchronous orbits are way out from the planet and costly, in many ways the "space game" of earth communications, earth monitoring, comms for earth wars has changed. Constellations of thousands of satellites in near earth obits, precessing for coverage, in near ellipitic orbits for relatively low cost repositioning over tagets of interest, and "not real satellites" - HAPS and blimps are changing the dynamics. Cheaper to launch, greater in number, and more easily moved about and|or replaced.