Imagine mankind has established mining facilities on NEOs
Some of them send raw ore directly to other processing stations in space, others refine on site.
All of them use a system based on cargo 'slugs' that get flung to their destination using rail guns. Near destination 'vectors' link with the cargo, slow it down and bring it in.
This is economical as only a few vectors would be needed at destination while there may be hundreds of cargoes traveling along different trajectories, paced so that reception is possible.
The problem is there are regular launches from the NEO while mining the asteroid. This means the asteroid gets an equal impulse in the opposite direction. It's mass may be billions of times bigger than the cargo but it is reducing as it gets mined and over years of exploitation and launches the orbit is going to be altered.
Now, for some asteroids that may not be a problem, the final orbit can be calculated and be safe.
For some others that may not be the case. For instance they may be at the receiving end of cargo shipments too. Or the final altered orbit may become a hazard.
Is there another way to stabilize the orbit while keeping sending the cargoes without having to shoot an equal mass (maybe waste? but would there be enough waste? on metallic asteroids that may not be the case it seems) in the opposite direction?
- Our own solar system.
- Power generation is available at low price. Firing the rail gun more than once to stabilize the asteroid would not be an issue.
- Ion / chemical thrust engines such as those employed by vectors are available but much more expensive to use than rail guns.
- A slight variation in the orbit is not an issue. Vectors will adjust to it if cargo needs to be brought in. A large one happening in years of work may be.