Jon,
If debris in the size range of 1 to 10 cm is the problem population, I
think a (short range) tracking and targeting system already exists - the
Mu-band radar on the Phalanx CIWS for US Navy ships tracks and persecutes
targets down to "the size of a dime" or right around 1 cm - Mu band is
approximately 1.6 mm wavelength.
As cool as it would be to launch a Giant Robot Machine Gun into Space, I
think the idea would be to use the tracking and targeting hardware and
(partially) software from Phalanx and use it to drive a directed energy
system such as the one you specify. Among other issues, It'd be difficult
to reload 20 mm drum magazines in orbit...
Mike
From: Jonathan Yoke <jonyoke@xxxxxxxxx>
Date: Sun, 5 May 2019 14:47:49 -0700
Subject: [AR] Re: debris cleanup (was
Falcon 9 first stage reaches a max altitude of 150-160 km. Too low.
It seems the problem isn't deorbiting (yet), it's tracking. >10 cm we can
track from ground based stations and avoid via maneuvers (not ideal, but
not the wolf closest to the sled). <1 cm can be dealt with via shielding
or redundancy. It's <10 & >1 cm that's the problem. Too small to track,
big enough for a mission kill (6cm ball of Al is 500g, at 8km/s that's 16
MJ of KE, aka a dead satellite).
Also, that graphic is outdated. Current Starlink plans are to start with
1600 satellites at 550 km, then 2800 at 1150 km, and 7500 at 340 km.
Notice how they avoid the worst part of the "Traffic Jam."
I'm guessing the mega-constellation providers (SpaceX at the forefront) are
going to have enough of an incentive to solve this problem - at their
altitude. SpaceX is planning on doubling the number of active satellites
in orbit around the Earth with just their first wave. Sure part of the
plan is that some of the satellites will die (or be DOA) and have to be
deorbited, but eventually the scales are going to tip enough such that it
makes economic sense to find ways to actively deal with space junk.
Lasers have been brought up. I think developing and launching 5 to 10
satellites to actively protect a constellation of 1600 makes sense. Equip
them with ~100 km lasers and radar powerful enough to pick up objects >1 cm
in diameter at that distance (and a control system capable of hitting the
correct side of a spinning 6cm bolt with a laser at 100 km - the real
challenge) and then just let them go to work. It won't placate alarmists,
but using lasers with a max effective range of ~100 km would put these
satellites out of the range of earth - no military application.
Once the technology is developed and deployed by the mega constellation
provider, it could be sold to governments to clear altitudes that don't
necessarily interest the company.
