Governments Are For Gravity Wells

I wrote that in an article for the December 1983 Analog about the launch loop.

It came from a conversation with my friend Dick Pilz. Three decades later, I remember he invented it, and he says I invented it. So we agreed that I get publication rights and he gets T-shirt rights.

In a shared gravity well, your externalities eventually intersect someone else. "The breakfast garbage you throw into the bay, they drink for lunch in San Jose". In the best case, we manage ourselves and make agreements with others to contain or remediate or compensate the costs we might impose on them. In the best government case, we appoint some people to shoot us if we fail to keep our agreements. In the usual government case (thousands of historical examples) the government changes the agenda and shoots its opponents instead, adding to the externalities. Time to move to another gravity well, and establish good government there only when externalities grow too much.

I'm an engineer, so I prefer to design systems that minimize externalities, rather than generate them and then make agreements about them. With sufficient cleverness, the cheapest way is also the lowest-externality way. It takes energy and material to make pollution. Arguments about who to shoot for making a mess are pointless. The interesting question is, "How do we make clean technology humongously more profitable than dirty technology?"

A space launch example:

All prograde orbital launchers slow down the rotation of the earth a teeny tiny bit. A billion tonnes launched from a launch loop to L5 will remove some angular momentum from the Earth, add it to the payload, and lengthen each day by 860 nanoseconds. Not sure what the economic burden of that is, but let's multiply that by 7 billion people and a wage of $20/hr, just so we can quantify a cost. The launch company owes humanity as a whole about $12000 per year, perpetually. About 170 microcents per person per year. Perhaps the launch company can import some lunar material, prograde, and speed earth back up to compensate. Clean tech!

Rocket launchers don't just change the angular momentum, but turn terrestrial resources (petroleum and coal) into chemical crap in the atmosphere. About 780 metric tonnes (mostly solid fuel) of an Ariane 5 leave the pad to put about 3 metric tonnes of comsat into GEO - a little more delta V for launch and a little less delta V for apogee kick to go to L5, so the ratio of launch mass to orbit mass to L5 is still about 260:1 .

Sending a billion tonnes to L5 with rockets adds about 240 billion tonnes of rocket exhaust pollution in the atmosphere, quite a bit more manufacturing pollution. For comparison, humanity creates about 35 billion tonnes of CO₂ a year.

Launching a billion tonnes will fill nearby space with about 10 billion tonnes of empty third stage in transfer orbits, and about 1 billion tonnes of little globs of solid propellant exhaust from the apogee kick motors. We've multiplied the angular momentum loss by about 10x.

That 11 billion tonnes will "Kesslerize" into about 5e18 millimeter- sized grains in an equatorial ring at 2Re (which is my favorite MEO orbit, dammit!). If the ring is a torus, 2000 km minor diameter and 80,000 km circumference, the volume is 2.5E20 m3 and the particle density is 2e-3/m3 . At that height, those little particles will stay in orbit for thousands of years. It will still be high vacuum. With lethal sand.

Passing through the ring to outer orbits will encounter about 4000 particles per square meter of vehicle frontal area - a lot more if the angular momentum of ring and vehicle doesn't match. That will probably sandblast the vehicle to smithereens. Even if you carefully remove all the expended third stages, that will orbit even more solid fuel exhaust, so you can probably only remove 60% of the problem, at great expense.

And a billion tonnes is less than 10% of what we move around by land, sea, and air per year here on Earth. A truly spacefaring civilization will launch many billions of tonnes per year.

If we are serious about space, we need to do our accounting properly, and keep looking for clean launch technologies that we can use for a very long time.

Otherwise, we will have to keep creating governments to force least-bad practices on ourselves, and destroy them in violent and failure-prone revolutions when they go off-track. Nasty.

GovernmentsAreForGravityWells (last edited 2012-06-08 18:24:21 by KeithLofstrom)