[RocketBoy]

Hi. I have a question. In my story, my main characters have a plan to save their lives. They are in a rocketship orbiting a planet. Another ship, like a pirate ship, has sprayed the ship with a barrage of micro-meteoroids that have pocked all kinds of tiny holes in the ship. The worst damage was done to the hydrogen fuel tanks at the lower two thirds of the ship. Liquid hydrogen leaked out of the holes and froze and crystalized into spike like icicles. Now if they try to fire the engines, the ship will just explode.

So, their intrepid captain comes up with a plan. The will detach the fuel tanks. Pull away with what's left in the maneuvering jets and -when they have a little distance between them and the disconnected hydrogen tanks- they'll ignite them with a well placed raygun blast.

Their hope is that the shockwave of the explosion will push against the ship enough to slow it down so that it can enter the planet's atmosphere.

So, here is the question: Can a shockwave of an explosion travel through the hard vacuum of space? I see them do that on Star Trek all the time. But would it really work?

Thanks.

[thedragonstrike]

It does in Star Wars ... but according to real world physics, such an event would be implausible. The shockwave is a disturbance in the fluid, gas, or plasma mediums, so without such a medium for it to travel though, in the vacuum space, it simply wouldn't work

However, take my advice- if you're willing to bend the laws of reality in even a small way, that's fine for storytelling, unless you are adamant against it. There are several creative ways for such an event to take place, as a leaking of gas, traveling through a nebula, or perhaps occurring in the outer atmosphere of said planet. Some sources even say that such a disturbance is possible within an electromagnetic field- but to me, the physical force of an explosion, as we see here on Earth, simply would not have the same reaction in space without taking liberties in what you consider the laws of physics for your story.

Hope I could help.

[kmtolan]

Actually, the tactic would work if you could get the fuel tanks close enough to allow debris to strike the other ship and impart thrust that way. Basically, we're talking having your tanks explode right next to the oncoming ship.

Kerry

[mylinar]

The problem I see with this is that Hydrogen, in its native environment that being space, is a gas. There would have to be some special mechanism to change it from liquid to a solid. It won't operate like water leaking out but should instead sublime from liquid to a gas since there will be no pressure or containment facility to force it to be a liquid or solid.

[thehindmost]

in other words, boom right after the tank gets breached

[baragh]

The problem I see with this is that Hydrogen, in its native environment that being space, is a gas. There would have to be some special mechanism to change it from liquid to a solid. It won't operate like water leaking out but should instead sublime from liquid to a gas since there will be no pressure or containment facility to force it to be a liquid or solid.

agree with mylinar; anybody who knows much about chemistry will catch this one. Also, the Hydrogen being held as liquid in the container would mean it is under very high pressure - a rupture in this tank by itself could cause the tanker to be propelled through space.

However, it wouldn't be unfeasible for future generations to come up with some kind of safety agent to mix with the Hydrogen during transport. Or just make it a different hydrogen based compound/mixture altogether? (understanding that hydrogen would make sense as an abundant fuel source in space)

[goldhawk]

So, here is the question: Can a shockwave of an explosion travel through the hard vacuum of space? I see them do that on Star Trek all the time. But would it really work?

Sorry but as mentioned by thedragonstrike, no shockwave. No even a nebula is dense enough for a shockwave. Its particles are so far apart that they would act more like individuals than a gas.

Also, the hydrogen tank would explode because of the pressure in it, not because the hydrogen burns; you need oxygen to burn hydrogen and there is none in space. The only way for the tank to explode is if the engines are pointed directly at it, an unsafe design from the start.

If you want your crew to create an improvised rocket engine, have them use a remote-controller raygun to blast a decent-sized hole in it. The escaping gas would propel the ship in the opposite direction. The hole would be bigger than those created by the micro-meteoroids but small enough so the tank doesn't rupture and the gas doesn't freeze before it can escape.

It seems that all your best ideas don't work in the face of hard science. Why don't you ignore the science and go with them? Never let facts (even made-up ones) stand in the way of a good story. :)

[expatrie]

As to explosions, you've got a non-flammable (no oxygen in space for the hydrogen to ignite with) liquid in a pressure vessel that's been breached:

http://en.wikipedia.org/wiki/BLEVE

Depending on where the jet from the hole in the pressure vessel is, compared to the ship's center of mass, could start the ship either moving or twisting or both.

[RocketBoy]

Wow! Thank you all for taking the time to point some of this stuff out. I'll have to re-configure my daring battle in space to accommodate this new information. I've since found out that the genre I'm writing in is called "hard-retro rocketpunk". There's a great site called Rocketpunk Manifesto that has long, long discussions about what is and is not possible in the realm of popular sci-fi fiction.

I do have some questions. Now, I've really tried to find the answer to these questions on my own by poking about the net, but so far no luck.

1.) If a vacuum seal of highly pressurized liquid hydrogen fuel tanks of a rocket torchship is compromised, like by a breach by micro-meteors propelled by a rail gun of an enemy ship, I now know that the liquid hydrogen with sublime into a gas and bleed out (maybe with enough strength to propel this ship in an un-intended direction) but will the massive and fast loss in pressure cause the hydrogen inside the tank to boil, build up pressure and explode?

2.) If there was also liquid oxygen leaking into the compromised tank, itself sublimating into a gas, would this result in burning and an even bigger explosion?

You see, I want my chapter about the heroes clashing with the villainous space pirates to end with a real BANG! as well for them to escape near death. I'm trying to throw in as much action and crisis situations into my story as possilbe to make my heroes more heroic.

Well, it’s not really a pirate ship. It’s a bomber. You see the evil dictator of this Earthlike alien world, called Aesyra, has launched remote controlled robot drone ships that orbit his planet. Each bomber ship is equipped with a rail gun that can shoot stone projectiles (of various sizes) down at the planet. By the time they hit the surface they have the killing force of a non-radioactive multi-megaton nuke. This is how the evil Emperor Raja Shah Kang keeps would-be rebellious kingdoms enslaved – with fear of utter annihilation.

My intrepid crew of space heroes, however, tangle with one of the bombers (which is controlled by a ground pilot). The ship first shotgun blasts the pressurized air compartments with micro-meteorites as a sort of warning shot. Then it pulls up alongside the hero’s rocketship and fires a magnetic harpoon on a steel line and starts reeling it in. As our hero’s are drawn ever closer to the robot bomber it extends a pair of massive mechanical lobster claws to trap their ship.

At least that’s the idea at this point. Of course, my gallant space hero, Rocket Girl, is not about to taking this spacejacking lying down. Swashbuckling ensues.

[mylinar]

I do have some questions. Now, I've really tried to find the answer to these questions on my own by poking about the net, but so far no luck.

1.) If a vacuum seal of highly pressurized liquid hydrogen fuel tanks of a rocket torchship is compromised, like by a breach by micro-meteors propelled by a rail gun of an enemy ship, I now know that the liquid hydrogen with sublime into a gas and bleed out (maybe with enough strength to propel this ship in an un-intended direction) but will the massive and fast loss in pressure cause the hydrogen inside the tank to boil, build up pressure and explode?

2.) If there was also liquid oxygen leaking into the compromised tank, itself sublimating into a gas, would this result in burning and an even bigger explosion?


I belive the answer to #1 would be based on how large a hole was created. A micro pinprick might allow the hydrogen to escape so slowly that the pressure inside does not change too much. A larger hole would make such a differential that the liquid would almost certainly boil to some degree. How big a hole is unclear but I think that would fall into the category of writers discression without really bothering readers.

Question #2 should be very easy. After all what happens when liquid hydrogen and liquid oxygen mix together in Florida? It is (or was anyway) called a Space Shuttle Launch. I think this could be a very big bang in space, just don't add any sound effects like a Sci Fi movie does. :D