Moving Phobos to join Deimos for single moon.

[Drakkith]

Everybody seems to to have forgotten about the 5000 or so megatons of nuclear weapons we have lying around. That said, I'm sure we have means and the know-how to do this thing.

I've been purposely leaving them out, as most people have a huge issue with them.

 

[Ryan_m_b]

Would nuclear explosions actually help? Could it be controlled enough and could enough energy be provided?

EDIT: for clarity I mean with the weapons we have

 

[Lsos]

Honestly I really don't know. I really don't even know how a nuclear explosion works in a vacuum. Is there a fireball? Is there a shock? Is it just a bright flash of light and heat?

Since it's in space, I imagine the moon wouldn't be blown to bits unless the explosion happened inside of it. If we blew it up close to the moon, it would probably heat up/ vaporize the surface, resulting in a makeshift rocket?

I do know that the stockpile we have has enough energy to at least give the thing a proper nudge. There's a few ideas on how to go about delivering this nudge, and in this discussion we shouldn't be constrained to talking about only the stockpile we have. Surely more could be built/ modified with the idea of controllably moving a moon (and not uncontrollably moving a city).

 

[sophiecentaur]

Ideally, you'd insert it under the surface, opposite to the direction you wanted it to go. Then a small amount of mass would be ejected in one direction and the moon would go in the opposite direction. (Conservation of momentum / Newton III). Using some of the moon's mass in that way would be better value. The exact depth etc would depend on the energy and the 'rate' of its production (i.e. Power), I think.

 

[DaveC426913]

Ideally, you'd insert it under the surface, opposite to the direction you wanted it to go.

Current technology... We don't have robotic moon-mining tech yet.

Using some of the moon's mass in that way would be better value.

How much Moon would be left when we're done? How much would be dust in orbit, waiting to pulverize anything in its way?

 

[sophiecentaur]

Why are we being drawn to this thing like moths to a flame? It's towwwtally crazy from beginning to end.
I don't think you'd need to bury it very far - would a spade be 'current technology'?

 

[DaveC426913]

Why are we being drawn to this thing like moths to a flame? It's towwwtally crazy from beginning to end.

Because we like discussing stuff academically.

The question is: 'what technology don't we have'? Not 'how hard is it'?

I don't think you'd need to bury it very far - would a spade be 'current technology'?

1] What is the point in burying it 2 metres deep?
2] We don't have the technology to send a man, let alone hundreds, to Mars.

 

[sophiecentaur]

Because we like discussing stuff academically.

The question is: 'what technology don't we have'? Not 'how hard is it'?
1] What is the point in burying it 2 metres deep?
2] We don't have the technology to send a man, let alone hundreds, to Mars.

I'm not sure that the above comments are mutually compatible.
Either, we don't have the technology now so - end of conversation or what technology would we need? In which case, moon mining is as likely a scenario as are rockets to take the stuff there.

"Academically" is a good thing to aim at but I haven't seen many quoted figures on this thread. Engineering matters always should involve figures to establish possible feasibility. So is this thread really academic or just Buck Rogers and a bit of fun? (Not that it would matter)

 

[DaveC426913]

I'm not sure that the above comments are mutually compatible.
Either, we don't have the technology now so - end of conversation or what technology would we need? In which case, moon mining is as likely a scenario as are rockets to take the stuff there.

When someone first raised the idea of using nukes, there was no assumption that they had to be accompanied by humans.

"Academically" is a good thing to aim at but I haven't seen many quoted figures on this thread. Engineering matters always should involve figures to establish possible feasibility. So is this thread really academic or just Buck Rogers and a bit of fun? (Not that it would matter)

The question is straightforward: what technology are we missing?

We don't need to assign numbers to know that we don't have the technology to house the town of technicians required to move it manually. (And ou're right. If we did supply numbers, this would be a very short thread.) So now we're exploring methods that could be done remotely. Just for fun.

 

[sophiecentaur]

Yes - I get it.
I have the same with 'role playing' exercises in the work place, though. I never know when to be really in role or just to be realistic.

But if we were going to be letting off nukes all over that little moon, would anyone ever want to go there later?

But, why are we discussing this particular exercise at all? I would have thought that a much more interesting and relevant question to discuss would be what to do about a rogue asteroid on collision course with us. A very similar problem and it could actually have relevance this very afternoon!

 

[DaveC426913]

But if we were going to be letting off nukes all over that little moon, would anyone ever want to go there later?

True. An issue for the OP. He didn't say anything about it being usable afterward...

But, why are we discussing this particular exercise at all? I would have thought that a much more interesting and relevant question to discuss would be what to do about a rogue asteroid on collision course with us.

Yawn. Been hashed out a million times.

And the distances involved dramatically narrow down the solutions using current technology.

 

[sophiecentaur]

And the distances involved dramatically narrow down the solutions using current technology.

NASA would even be pushed to get to the ISS without some help.

 

[barycenter]

1] Why?
2] Depends on what you mean by current technology. With current technology, we could build a superhighway around the equator, but it would break the budget of a passel of large countries.

Answer: Why?
1) To give NASA a large goal that doesn't require the negative PR of human loss.
2) To give NASA the time to formulate a plan, practice, and create the tools necessary to move an asteroid or comet when it is on a collision course with Earth (The Universe: Season 3, Ep.6 - Deadly Comets and Meteors)
3) I'm working on a Theory that will help humans colonize Mars but needed to know if moving Phobos as a whole was feasible or if it needed to be taken apart.

 

[barycenter]

Totally agree. Sticking with the stipulation that we can only use current technology there's no way this would be a manned mission. It would have to be robotic with delayed telepresence.

Do you believe some sort of large focused nuclear explosion could exert enough force to move Phobos into a higher orbit without shattering it? Or would a small oscillating force over a long period of time be a better approach? Any possibility of making fuel from Phobos itself?

 

[D H]

Answer: Why?
1) To give NASA a large goal that doesn't require the negative PR of human loss.

Without that human element NASA will go the way of the British space agency.

2) To give NASA the time to formulate a plan, practice, and create the tools necessary to move an asteroid or comet when it is on a collision course with Earth (The Universe: Season 3, Ep.6 - Deadly Comets and Meteors)

The delta-v needed to move an asteroid or comet off a collision course with the Earth is much, much smaller (many orders of magnitude smaller) than is the delta-v needed to make Phobos collide with Deimos. If you want to make that a gentle collision so that they become a single moon you will need to more than double that already huge delta-v. This is not a realistic goal.

3) I'm working on a Theory that will help humans colonize Mars but needed to know if moving Phobos as a whole was feasible or if it needed to be taken apart.

Time to go back to the drawing board.

 

[barycenter]

The delta-v needed to move an asteroid or comet off a collision course with the Earth is much, much smaller (many orders of magnitude smaller) than is the delta-v needed to make Phobos collide with Deimos. If you want to make that a gentle collision so that they become a single moon you will need to more than double that already huge delta-v. This is not a realistic goal. Time to go back to the drawing board.

So you don't believe humans could move an asteroid to avoid hitting Earth?

Phobos and Deimos wouldn't have to join overnight, just make enough of an alteration in the direction of Phobos to travel faster than Deimos is traveling away from Mars, like Earth's moon is currently doing. Eventually Phobos will catch up to Deimos (5,10,15 years). This way while NASA is not around, the work can accomplished without our constant intervention.

The farther away from Mars Phobos traveled, the more attraction Deimos would have on Phobos (and vice versa). They would eventually create a single moon, and a single unified force of tidal friction on Mars.

 

[Ryan_m_b]

So you don't believe humans could move an asteroid to avoid hitting Earth?

Phobos and Deimos wouldn't have to join overnight, just make enough of an alteration in the direction of Phobos to travel faster than Deimos is traveling away from Mars, like Earth's moon is currently doing. Eventually Phobos will catch up to Deimos (5,10,15 years). This way while NASA is not around, the work can accomplished without our constant intervention.

The farther away from Mars Phobos traveled, the more attraction Deimos would have on Phobos (and vice versa). They would eventually create a single moon, and a single unified force of tidal friction on Mars.

I think this is a vastly simplistic model. Trying to boost Phobos's orbit would require precise control to avoid it loosing energy and crashing into Mars, assuming you could actually manage to get them into the same orbit and close together you still have the problem of how to safely combine them. They aren't made out of play-doh! Two moons closing together at the speeds that they will would cause them to shatter.

 

[SpectraCat]

So you don't believe humans could move an asteroid to avoid hitting Earth?

Phobos and Deimos wouldn't have to join overnight, just make enough of an alteration in the direction of Phobos to travel faster than Deimos is traveling away from Mars, like Earth's moon is currently doing. Eventually Phobos will catch up to Deimos (5,10,15 years). This way while NASA is not around, the work can accomplished without our constant intervention.

The farther away from Mars Phobos traveled, the more attraction Deimos would have on Phobos (and vice versa). They would eventually create a single moon, and a single unified force of tidal friction on Mars.

This is all about tides? Phobos and Deimos are *tiny* 6 or 7 orders of magnitude smaller than our own moon (in terms of mass). I doubt they would have much effect on tides, certainly not nearly as much as the effect of the moon on earth, even if they were somehow combined.

 

[D H]

So you don't believe humans could move an asteroid to avoid hitting Earth?

I said nothing of the sort. Moving an asteroid off a collision course with the Earth is a trivial task compared to moving "Phobos to join with Deimos to create a single Mars moon".

Deimos would make for an extremely large asteroid. Phobos: Absolutely huge. Making Deimos merge with Phobos is an impossible task given our current technology. Making Phobos merge with Deimos? Please! Assume we have some Saturn V style rockets (specific impulse = 4130 m/s) attached to Phobos. The amount of energy needed just to move Phobos as described is on the order of 10²² joules, or 1000 times the total electrical energy produced by the US per year. This completely ignores the energy needed to move the fuel and oxidizer to Phobos. The task is impossible not only with current technology, it is impossible given any reasonable extrapolation of technology. (Suppose we have a flux capacitor (1.21 gigawatts). In fact, suppose we have half a million flux capacitors at hand. You would have to run those half a million flux capacitors continuously for almost a year to produce the energy needed here.)

Moving an asteroid off a collision course with the Earth is indeed trivial in comparison. The required delta-v is many orders of magnitude smaller than that required to move Phobos, and the mass of a typical near Earth object is also many orders of magnitude than that of Phobos. (Phobos is huge).

Phobos and Deimos wouldn't have to join overnight, just make enough of an alteration in the direction of Phobos to travel faster than Deimos is traveling away from Mars, like Earth's moon is currently doing. Eventually Phobos will catch up to Deimos (5,10,15 years). This way while NASA is not around, the work can accomplished without our constant intervention.

Wrong. A tiny nudge to Phobos is going to change its orbit a tiny bit. Phobos' orbit has a semi major axis of 9,377.2 km; Deimos' is 23,460 km. Do the math. The minimal delta-V to accomplish this desired merger is attained by a Hohmann transfer, 417.5 m/s to start the transfer, 330 m/s to finish it, or 747.5 m/s total. Using thrusters with a 4130 m/s specific impulse, having fuel continuously transferred to Phobos, ignoring the energy needed to accomplish this fuel supply, and ignoring gravity losses due to continuous thrust, this 747.5 m/s delta-V translates to 1.65×10²² joules. Continuous thrust would only serve to increase the energy required.

 

[DaveC426913]

3) I'm working on a Theory that will help humans colonize Mars but needed to know if moving Phobos as a whole was feasible or if it needed to be taken apart.

This little tidbit may have slipped under the radar, yet it seems to be the driver for the entire thread.

If I had to guess, you're thinking about combining the two Moons in the hopes that it will give Mars some sort of tidal effect?

1] Many orders of magnitude too small.
2] Tides will not make Mars habitable.
3] Read Arthur C. Clarke's The Sands of Mars where they made Mars habitable by setting Phobos on fire.

 

[barycenter]

This is all about tides? Phobos and Deimos are *tiny* 6 or 7 orders of magnitude smaller than our own moon (in terms of mass). I doubt they would have much effect on tides, certainly not nearly as much as the effect of the moon on earth, even if they were somehow combined.

True, but currently Phobos and Deimos do not orbit Mars in an Orbital Resonance like Io, Europa, and Ganymede do with Jupiter. If we could create an Orbital Resonance with the moons of Mars, tidal friction would occur, possibly heating up Mars interior, to melt underground ice, releasing liquid water, making it easier for astronauts to create fuel, food, structures, etc. etc.

 

[barycenter]

If I had to guess, you're thinking about combining the two Moons in the hopes that it will give Mars some sort of tidal effect?

1] Many orders of magnitude too small.
2] Tides will not make Mars habitable.
3] Read Arthur C. Clarke's The Sands of Mars where they made Mars habitable by setting Phobos on fire.

1) Think what Tesla achieved in the field of "Resonance" with just a small oscillating piston. Now ask yourself, would life exist on Earth without the moon? No - This can be assumed because we have not found life on planets with zero moons, nor on planets with more than 1 moon, but have discovered life on a planet with 1 moon. Watch "If We had No Moon" http://www.youtube.com/watch?v=wW_vmnfTeWM&feature=related . But a small Mars moon would be just the beginning to putting together a Mars moon equal to the Earth/Moon ratio that we see today.

2) Correct - but Liquid water will. And if a single moon is created, it will create tidal friction. Friction releases heat, which could melt ice, releasing liquid water which can be drank, used to grow plants for food, used to help create adobe houses, make factories, etc.

3) The sands of Mars was written 50 years ago and is a Science Fiction novel, which means it is not true. But do you think it is our job to try and make Mars habitable?

Thank you everyone your input is helping me to prepare to present my theory. If you have any other ideas, please feel free to write them down here. Remember, there are no wrong answers.

 

[Ryan_m_b]

1) Think what Tesla achieved in the field of "Resonance" with just a small oscillating piston. Now ask yourself, would life exist on Earth without the moon? No - This can be assumed because we have not found life on planets with zero moons, nor on planets with more than 1 moon, but have discovered life on a planet with 1 moon. Watch "If We had No Moon" http://www.youtube.com/watch?v=wW_vmnfTeWM&feature=related . But a small Mars moon would be just the beginning to putting together a Mars moon equal to the Earth/Moon ratio that we see today.

This is incorrect. We do not yet have a comprehensive http://en.wikipedia.org/wiki/Abiogenesis" so you cannot just pick something about the Earth and suggest that this gave it life. It is naive to ignore everything else that is different about the Earth such as it's orbit, water, magnetosphere etc.

It has already been pointed out that the energy needed to combine Phobos and Deimos would be gargantuan, it's hardly feasible to suggest increasing the mass a further 6 or 7 orders of magnitude.

2) Correct - but Liquid water will. And if a single moon is created, it will create tidal friction. Friction releases heat, which could melt ice, releasing liquid water which can be drank, used to grow plants for food, used to help create adobe houses, make factories, etc.

It is not that simple at all. To grow crops on Mars would require the relevant soil biology, soil nutrients, climate, atmospheric qualities etc.

3) The sands of Mars was written 50 years ago and is a Science Fiction novel, which means it is not true. But do you think it is our job to try and make Mars habitable?

What you are proposing is also science fiction. As for "our job" I am unaware that terraformer was an actual profession nor that we on this forum were in that field.

 

[D H]

Thread locked. barycenter, please read our rules on overly speculative posts.