Earth needs a Good Comet Deflector, why not reuse the International Space Station when its current useful life is over?

[RobertSenger]

Earth Needs A Good Comet Deflector. It seems to me that they could put new rockets on the International Space Station when it's current original useful life is used up and then push it up into higher orbit perhaps a lunar orbit; then make a comet deflector out of it. Perhaps give it a large spiderweb of cables and girders so it can wrap around a number of different types of potentially earth-impacting objects. The added engines would then be used to move the dangerous object. If a hundred years or so goes by and it doesn't get used as a comet deflector, it could be landed on the moon as a tourist attraction saving it for future generations to appreciate. Due to the mass of the International Space Station, it would be very useful under many circumstances as a comet deflector if it could be strengthened and moved to the right orbit. Why not do that when its useful life has passed? The cost to do it is getting cheaper every day.

 

[Catastrophe]

We certainly need to guard against the possibility of a catastrophic impact. I am not sure about catching impactors in a net and towing them away. We have to bear in mind the energy requirements and what options are available to us. And - a very large factor - the time available to us to take appropriate action.

As far as I can see, if it is small enough to tow away, it is probably too small to do any damage - probably too small to survive crossing through the atmosphere.

Cat

 

[RobertSenger]

We certainly need to guard against the possibility of a catastrophic impact. I am not sure about catching impactors in a net and towing them away. We have to bear in mind the energy requirements and what options are available to us. And - a very large factor - the time available to us to take appropriate action.

As far as I can see, if it is small enough to tow away, it is probably too small to do any damage - probably too small to survive crossing through the atmosphere.

Cat

I was thinking of using the large spiderweb of girders and net of cables that would be attached to the international space station as a way to slowly put pressure against a large area of the surface of a rubble pile mountain of a comet. Then using the engines to nudge it off its trajectory; this nudge could just change its trajectory a fraction of 1° but that could be enough for a mountain size comet to miss the earth completely. We don't have to use a lot of energy to capture the comet, just use the large engines that would be added to the International Space Station when it is reconfigured to be a, Comet Pusher, to nudge it off its trajectory, So we don't have to use a lot of energy to capture it, but if it turned out to be a large iron object then we could use the engines to get the international space station up to a very high speed and then impact it to knock it off its trajectory. When we use the current mass of the International Space Station and add to it the mass of the parts beefing it up, plus the mass of the engines, will have something of a fairly decent size mass that at a very high speed could actually do the job changing the trajectory on a very large solid object as well.

 

[Catastrophe]

Robert Senger, you are to be commended for your tenacity, but I think you need to check some of the practicality. You talk about the great mass of the iss - then how easy it would be to move it.
Much of what you say might work well, but you seem to assume that the impactor and ISS would be within easy reach. What if the impactor is coming from a polar direction? This would be quite possible for a large comet.
The main issue is the amount of fuel/energy versus the mass of the impactor, and the time available. On the one hand, there is talk about seeing it months, or even years, ahead. Then we hear about potential impactors whizzing by, unseen until after they have gone. OK, I accept that if it can be seen way ahead, it would be very large. But if too large, we would probably be powerless to stop it. And those whizzing by unseen would be relatively small - but in between these extremes there is a wide spectrum.
There is a great deal of misunderstanding, imho, in this area. You have a few options, which may be double-edged. Painting one side black and one side white would use up a lot of energy getting there and back (assuming the object is seen well ahead). What if uneven shape causes tumbling when it might be driven nearer? Physically attaching chains and towing away assumes the process is easy. Of course, it all depends on the size of the impactor. Calculate the mass of the chains et cetera and the energy to get them out there. Then attacking with nuclear bombs is double-edged. You might create a dozen fragments which cause more damage than one. Maybe create impactors out of an object which might have just skimmed by. Also many potential impactors consist of loose bound aggregations. Bombing might have very little effect. This is particularly the case if the bombing is intended to change direction of the impactor - it won't.
It all comes down to how much energy is available (in terms of fuel, bombs, et cetera) and the time available. I laugh when I hear about plodding off to paint asteroids approaching at a zillion miles a second (OK, you get the point).

Cat

 

[RobertSenger]

Time is definitely going to be an issue but if the ISS is in a lunar orbit, with the previously mentioned upgrades, with powerful engines fueled and ready for action, the amount of time for something that is a considerable distance out is going to be enough, especially if the concern is of impact with Earth is with a comet's outgoing trajectory after it swings by the sun. There would be many circumstances in which this would not work, but under some circumstances, with certain large comets, it would have enough time and could work. My argument would be that the cost of adding engines to the ISS when it is retired and putting it in the lunar orbit would justify its existence and cost. No doubt in order to have a defense system against comets a comprehensive system with many different options would have to eventually be put in place.

 

[Catastrophe]

You need specific examples to discuss logistics, but the general picture is governed by energy/fuel ability, size /mass of potential impactor, and time available to carry out the necessary procedure.

Energy/fuel is governed by mass to be transported over what distance, and this must include the mass of fuel to be used up in the transportation. Fuel consumption can increase steeply with acceleration, which links into time constraints.

The mass of the potential impactor will govern the choice of deflection choice. Its distance and velocity will control the time element. The larger the impactor and the further away it is will control the amount of fuel consumed in transportation as well as any to be used in the deflection mechanism, such as in rockets pushing/pulling the impactor.

The time available is governed by the distance of the impactor and its approach velocity. The faster it is approaching, and the closer it is, the more fuel will be expended in reaching it.

As you can see, this is a complicated process, not open to 'off the top of your head' short cuts. I am a professional chemical engineer and this is exactly the practical approach required. Beware of jumping to conclusions without considering the consequences.

Cat

 

[yaduff]

I was thinking of using the large spiderweb of girders and net of cables that would be attached to the international space station as a way to slowly put pressure against a large area of the surface of a rubble pile mountain of a comet. Then using the engines to nudge it off its trajectory; this nudge could just change its trajectory a fraction of 1° but that could be enough for a mountain size comet to miss the earth completely. We don't have to use a lot of energy to capture the comet, just use the large engines that would be added to the International Space Station when it is reconfigured to be a, Comet Pusher, to nudge it off its trajectory, So we don't have to use a lot of energy to capture it, but if it turned out to be a large iron object then we could use the engines to get the international space station up to a very high speed and then impact it to knock it off its trajectory. When we use the current mass of the International Space Station and add to it the mass of the parts beefing it up, plus the mass of the engines, will have something of a fairly decent size mass that at a very high speed could actually do the job changing the trajectory on a very large solid object as well.

I don't know... That sounds a tad far fetched, also I think you would have a hard time convincing NASA, and that is assuming that your idea would work

 

[Classical Motion]

Comet velocity is your problem. It takes time to turn. And to catch or attach something to it......you have to match it. Any slow structure in it's path is doomed.

So to divert a comet, match it's speed and do it far enough away for turning time. Otherwise nuke it.

 

[yaduff]

So to divert a comet, match it's speed and do it far enough away for turning time. Otherwise nuke it.

Agreed!