(My laptop is three years old, and died near the end of James Dunstan's talk. My father was taking notes on the Orbital Debris Panel, so the review of the panel below is based on his notes.)
Some of the big questions are:
What are the approaches to debris removal?
Who should pay?
Is this the time to attack
Remove 5 objects per year, keep growth down. Doesn’t need to clean up 17,000 objects.
Dennis – no slides. Business case. His European company, orbital recovery. 1998 Delta 2 recovery – plane change, not de-orbit – hit something at de-orbit fault, (God’s fault if random decay). Three orbital regeims – LEO / NEO – most of the orbits – fast majority are government assets. These guys are not ready to part with money. GEO orbit – different animal. ~276 active spacecraft in GEO orbit. About $90 M assets. Insurance policy – duty of care. Magic word – do something. FCC ruling (few years ago) had to move to grave yard orbit at end of life. AmSat claimed would cost big – use 6 months of station keeping orbit fuel to go to grave. There is a dead bird that is being watched. Revenue potential - $100 M/year per bird (!?) Market – end of life – we’ll move your bird. If 6 months is $50 M – can justify something. Until move one, flip chart company? Another market – replace all 276 birds in the next 2 years. Closure at 700 m/s, Not move graveyard as far
Mine the asteroids? Might first gather metals from space debris.
Joe Carroll
Small vs Large Debris Objects - there are different issues.
Small objects – trackable object many, drag makes unpredictable. Threat – (? 500 tons gross)
1900 tons in big stuff – but creates small stuff in collisions. 823 objects > 10 cm from Irredium. 16 Zenit stages, 1900 lbs each – if they collide, double the trackable debris population.
Debris is clustered = 817 tons – 739 objects 81-83 inclination (97% Russian)
480 tons, 644 objects 69.9-74.1 degrees (95% Russian
Sun Sinc – 96-97 low altitude , 103 high 322 tons, 316 objects,
Other inclinations 282 tons, 389 objects – only 15% in other – allobjects > 25 kg.
Propellantless propulsion – 100 m/s / day. E-W thrust with classic orbit – not much help with polar. Field lines are vertical near pole. Spin tether horizontally – can get arbitrary .
Mission time line – change plane – climb power. Drag – tape resistance & plasma density.
Drag things below ISS? God decides when & where to reentry. Stay in inclination cluster. 240 objects – degree climb 150 KM, get phasing, sync inclination, plane change. Take pictures, capture . 3 days to drag it down. Climb 200 km/day. 66 hours – say 1 object per week - 5 years, would clean up 10% of debris, with 100 Kg device. After proof of principle, twist arm of Russians.
Small stuff – laser – ASAT – bad vibes because it creates debris. Change mind set if clean up debris. Initiative
96-103 - total: 316 objects, 322 tons
US 155 objects, 85 tons
US allies – 80 objects, 85 tons
Russian 42 objects 93 tons
China 39 objects 59 tons
Other inclinations total: 389 objects, 282 tons
US 218 objects 105 tons
Russia 126 objects 159 tons
Other 45 objects 18 tons
Jeff Foust – what’s going on, politically?
There is a lot more talk about removing debris. No clear financial model for how to pay to have objects removed. There is an International Debris conference in a month. There is a ruling that uncontrolled satellites have been abandoned and available for salvage. No one has acted on this yet. In the long run the small stuff will be cleared out. The full agenda
Someone made the claim that stuff in orbit around earth was generating a hundred billion dollars a year. Lots of debris would impact that huge revenue stream, and so there was interest at several levels to keep space junk from killing revenue producing satellites.
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