# How would you realistically 'bump' a ship off of an Asteroid?

In my sci-fi universe (The same as my first question) it is common throughout the asteroid belt to 'Bump' (somehow cut off and then shove a ship off of an asteroid) miners. Usually this is only done to small scale mining operations that haven't established much on the surface of the asteroid (so they can bump the ship and then re purpose the basic mines they built)

In Warlords (The universe name) ships are usually tied down to asteroids by large re purposed docking cables that are drilled into the Asteroid to ancher the ship. To actually mine the miners use either exo-craft or space walk to the surface of the asteroid to establish the first searcher tunnels on the Asteroid.

Now the part that I'm actually stuck on is the 'how'. I've gotten to the simple 'Cut the cables', but how would you then shove the ship away from the Asteroid? Also for bonus points: Is there any way that you could 'Bump' a ship without severely crippling the ship (So they can limp away and not become a liability), destroying it, or killing the crew (both of these would create a scene most likely)?

Note: Most ships make use of Ion drives normally supplemented or working with Fusion Reactors (the fuel for these I'm still trying to figure out, but He3 seems like a good idea). Finally for quick bursts of speed plasma propulsion using H3 is used. Ship sizes are usually pretty large (In my mind) for mining ships usually having a large family (20-30 individuals) as the basic crew. Being around 100-200 meters in length for the average mining vessel.

I had a ship looking something like this in mind:

Image by Kevin Massey.

PS: I'm going to put the science based tag for now because I want a realistic answer to the bumping question (but I don't want someone to spend hours crunching the numbers)

• sweet ship! Be sure to credit artist with a link. – Willk Jun 9 '18 at 18:28
• Got his name in the corner but I just picked it off of the internet (I'll try and find a name though) – Celestial Dragon Emperor Jun 9 '18 at 20:36
• There's a whole plot line revolving around this exact situation in Orson Scott Card's Earth Unaware with pretty good detail on how the aggressors go about pushing the victims off an asteroid. – Gabriel C. Jan 8 at 20:58

Just bump them!

After you have severed the cables - since asteroid gravity is negligible - even the tiniest thrust is enough to accelerate the victim ship away. So you approach slow (say 1m/s) that the collision is not too destructive, and upon contact, you fire up (slowly) your engines to push the other ship away. Even if the victim has superior thrust, with carefull manouvering you can hit it in the side, so it can not 'bump back'.

Or if you do not want to scratch the paint on your ship's nose, you can fire on them low velocity, non-rigid slugs or missiles to push them away.

EDIT: On crippling/not crippling victim ship by side bumping

Sadly I dont think there will be repeated counter bumping.

In space every gramm counts. So non-military vessels will have much more acceleration tolerance in the thrust axis of their main engines than in any other direction. Like these. This means that if you manage to hit your victim in the side, they are at your mercy. If you are sure that they will get the message (that you are the big guy on this rock, and that they better leave) you would just bump them gently (just the acceleration needed to overhelm their RCS thrusters), but if you are the weaker and more desperate party, you will use full acceleration, severing their load-bearing structure with the non-planed-for acceleration (and perhaps throwing them sideways from their crash chouces, breaking propellant feed lines, etc...) leaving them crippled and waiting for rescue.

• Thanks for the answer! simple and blunt. Going off of your second Idea now I have the image of some sort of 'latching Torpedo' (affectionately called Remoras) – Celestial Dragon Emperor Jun 9 '18 at 15:22
• Happy to have helped ignite your imagination. Maybe smaller and more manouverable ships have a 'rubber ram' on their nose, while bigger vessels rely on sandbag cannons to keep those wanting to bump them in the side at bay. – b.Lorenz Jun 9 '18 at 15:27
• Yet it makes sense. Synthetic rubber (or any elastic material) is expensive. But since no asteroid is made from 100% valuable elements, there will alwasy be SiO waste. (basically sand) You fill the sand into a plastic bag, and lanuch a large bunch of it with some catapult at low speed (maybe 30m/s). Upon impact it delivers it's momentum, pushing the target away. It has advantage over elastic projectiles: it does not bounces off, so it may be possible to recollect it, and not leave it afloat in solar orbit. – b.Lorenz Jun 9 '18 at 15:42
• @yobddigi crippling them might be the go to. While bumping them you also try and cripple them into a state that they are forced to limp away to a station for repairs. – Celestial Dragon Emperor Jun 9 '18 at 16:28
• Side in this context means any direction not paralell to the thrust vector. Includiing the 'upwards' on the picture. And of course they can bump you back. It is a question of piloting expertise and nerve Who will give up/Who will fire live bullets? – b.Lorenz Jun 9 '18 at 16:28

I love a quote from Star Trek VI: The Undiscovered Country:

The thing must have a tailpipe!

Recapture a portion of the gaseous output of your own engines to be used pneumatically — in other words, give them an air blast!

The AstroConquerer class mining vessel model XN1-37748 comes
standard with the patented Halstrom EGR system with convenient
distribution points on the hull for blowing off dust and debris
accumulated during the mining process.


"And with a few extra pipes, it's useful for blowing 'dust and debris' off our asteroid, eh Johnny?"

• Makes total sense to me seeing as its cheaper to make use of a material or system you already have in place/use then having to install a brand new system for 'bumping' or buying some fancy equipment – Celestial Dragon Emperor Jun 9 '18 at 15:57
• I think it is less efficient than direct rambumping I have proposed. Any gas released into vacuum expands quickly in all directions, so the pressure drops with distance extremely fast, most of the blast going into waste. (This is the reason explosives are less effective in space) And since you are shooting exhaust into both directions (from the engines and from the bump-valves, engine firing being neccesarry to prevent reaction force from bumping yourself away) you are essentially wasting precious propellant when compared to direct ramming. – b.Lorenz Jun 9 '18 at 16:35
• And pipes able to channel ion-drive exhaust are quite nontrivial and definitely not cheap. Their high efficiency originates from their extreme exhaust velocity. trying to direct it with a metal tube would get the tube melted/eroded. Most probably you would need superconducting magnets. – b.Lorenz Jun 9 '18 at 16:37
• I vote against this because gases (especially air) are pretty valuable and hard to replace while in a hard vacuum. A few mechanical loading arms chucking lumps of worthless ore, however, might get the job done. – Pinion Minion Jun 9 '18 at 16:46
• Simple solution always better than complicated. And if your recapture rate is small, the thrust excerted on the victim ship would be small too. And if you actually manage to divert ion engine exhaust, its effect would be more like a weak particle beam, not a strong, pushing wind. – b.Lorenz Jun 9 '18 at 17:20

Malicious Hacking

Your crew of skulduggerous miners use malicious hacking to hijack the ship and get it to shove off on it's own. Or maybe they use this access to the opposing ship's computers to generate a false alarm regarding asteroid instability, or a dangerous incoming solar storm to ensure that the opposing crew are all shacked up in radiation shelters when they use an alternate physical method to shove the enemy ship out of the way. I particularly like the idea b. Lorentz suggested in one of the comments that utilizes a pneumatic sand-bag cannon.

But Why?

I think a bigger question that needs answered is why competition over these space rocks is so heated. It is estimated that over 150,000,000 asteroids 100 meters in diameter or larger are present in our solar system. Whats in these asteroids that is so valuable its worth risky maneuvers and violent competition to gather them? Nickel and Iron are not exactly going to be at a premium in a society with access to literally hundreds of millions of potential mines for such materials.

• Hacking was my first thought – yobddigi Jun 9 '18 at 16:14
• @TCAT117 I didn't suggest the sand bag thingy. b.Lorenz did. Now to answer the why question. I know that some asteroids would have traces of harder to reach minerals on earth (stuff trapped in the mantle), but are easier to access on Asteroids. Now while Iron and Nickel might not be worth much to the Terrans or Martians in the belt its probably worth much more due to being locally sourced and far easier to obtain then Terran Steel. – Celestial Dragon Emperor Jun 9 '18 at 16:26
• True enough, will edit accordingly. Thing is, with 150 million possible exploitation sites isn't it going to still be cheaper and less risky to just locate a new claim? – TCAT117 Jun 9 '18 at 16:27
• I would rationalize it as: "We know for sure this Asteroid has what we want from the scans". So in some cases it might be worth just bumping a ship for guaranteed resources instead of possibly searching for another and finding nothing of worth. Or possibly desperation could play a factor. So lets say a ship only has enough fuel for a few more weeks of operation so they need a quick pay day. Bumping a ship that has already established some mines on the asteroid could provide this. – Celestial Dragon Emperor Jun 9 '18 at 16:32
• Good idea, I just thought of something too. Maybe these hodge-podge family set ups lack the expensive and powerful scanners and detection equipment that larger more sophisticated corporate mining rigs posses. The wild-cat mining rigs just can't afford them, but if you find a corporate rig boring into a rock...... well you don't need to afford good scanners to know there is something valuable there if you just jump their claim. – TCAT117 Jun 9 '18 at 16:40

Sapper-Miner.

https://en.wikipedia.org/wiki/Sapper#Miner

The saps (combat trenches) permitted cannon to be brought into firing range of the besieged fort and its cannon, but often the cannon themselves were unable to breach the fort walls. The engineers would dig a tunnel from the forward-most sap up to and under the fort wall, then place a charge of gunpowder and ignite it, causing a tremendous explosion that would destroy the wall...

So too on the asteroid. A rival group digs a mine under the undesirable ship and sets off an explosive. This explosive cracks off the hunk of stone the ship is moored to, and also serves as the impetus to put the whole thing (asteroid fragment and ship) in motion out and away from the asteroid in question.

With a little luck the inhabitants of said bumped ship might not know they were bumped until they venture out. Mooring cables are all intact. Relative position to asteroid unchanged. Their asteroid has just become very small.

• This could work on the larger asteroids (smaller ones you could run the risk of shattering them) only issue I see is what if they moored directly over a deposit of materials that you would then run the risk of losing so valuable minerals. – Celestial Dragon Emperor Jun 9 '18 at 22:22

## protected by L.Dutch♦Feb 3 at 12:03

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).