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Posted

Well EM drive is a cool idea but without super conductors its going exactly the same place as the 95% efficient electric motors, commercial mag lev trains and a boat engine that is just a tube wrapped in copper wire. (I will give you a clue, saline solution).

However, this does work.... https://www.youtube.com/watch?v=wg2T7MUULZQ

Ok the physics.. as many of you may already know, Mach 2.6 is about as fast as your going to go with a jet engine. Anything over that and friction heats the air to about 1000 degrees centigrade and you loose reaction. To get to escape velocity you need to be going pretty fast so you take the fuel and the oxygen needed to burn it, with you. Hence big Roman Candles at Cape Canaveral.

This thing simply super cools the air before it hits the reaction chamber. Mach 5+ and you can use the local O2 until you get high enough to kick in you on-board supply to finish the hop into space. It's also possible that this engine burns possibly hydozine or hydrogen, we Brits tended to avoid that horrible Kerosine RP1 stuff..

Posted

It's also possible that this engine burns possibly hydozine or hydrogen, we Brits tended to avoid that horrible Kerosine RP1 stuff..

It's interesting that you call kerosene horrible stuff while hoping for a rocket fueled with hydrogen peroxide or hydrazine, as both are horrible fuels to deal with.

That hydrazine is the fuel used in most attitude thrusters says far less about how nice it is than it does about how terrible the rest of the monopropellants are, because hydrazine is nasty stuff.

I mean, I suppose hydrogen peroxide has the advantages of being relatively non-toxic and clean-burning, but it also has the disadvantage of being WILDLY unstable. In that it breaks down exothermically(releasing heat), and breaking down with heat(among many, many other things). Which results in a vicious chain reaction as it begins to break down, heats itself up, breaks down faster because of the heat, heating itself more, in a race to the combustion point. And since it's a monopropellant, it's fuel AND oxidizer. So when it reaches that combustion point, the entire mass bursts into flame all at once. Bad in a spill, worse in a tank.

That said... we Americans use liquid hydrogen and liquid oxygen for our main engines these days.

If you can find a copy, I strongly recommend reading John Clark's "Ignition!: An Informal History of Liquid Rocket Propellants". It is both hilarious and educational, and written to be accessible to non-physics majors.

Posted

Although not a specialised subject of mine, I do have a general interest of rocketry edging towards the history of it. So I look forward to searching the book out.

My reference to "Horrible Kerosine" was more a tongue in cheek jab at the fact that British Rocketry followed on from the V2 program after the war and made some significant breakthroughs. Although our own "Bluestreak" program used 2 Rolls Royce RZ2 Engines developing a rather respectable for the size, 150,000 lbs of thrust each using Kerosine & LOX.

Hydrogen is cleaner burning and should keep the environmentalists happy, but I also believe you get more power for weight ratio. I think I read somewhere, that some of the final stages of the Staturn V used Hydrogen Propellent but I'm not sure.

P

Posted (edited)

All but the first stage of the mighty Saturn V were H/O engines. Which was novel at the time, if I recall.

Edited by JB0
  • 1 month later...
  • 4 weeks later...
Posted

I thought I read somewhere that it was flowing water too?? It would be cool to see if Elon Musk's idea of nuking the poles to melt the ice would actually do anything toward restarting the planets environment or would it just radiate the water and evaporate / escape into space..?

Posted

I thought I read somewhere that it was flowing water too?? It would be cool to see if Elon Musk's idea of nuking the poles to melt the ice would actually do anything toward restarting the planets environment or would it just radiate the water and evaporate / escape into space..?

It's very faint amounts of very salty flowing water.

There's serious questions about how it's GETTING to the equator, since there shouldn't be enough atmosphere to carry water vapor that far and any near-surface ice should've evaporated ages ago.

Nuking the poles is a bad idea. Better to attack an ion engine to an asteroid and drop THAT on the poles. Easier, cheaper, more effective.

Posted

Why not just activate the ancient ice-melting machine that the ancestral martians left buried on the ground?

Jeez... always with the complicated ways you guys....

Posted

It's very faint amounts of very salty flowing water.

There's serious questions about how it's GETTING to the equator, since there shouldn't be enough atmosphere to carry water vapor that far and any near-surface ice should've evaporated ages ago.

Nuking the poles is a bad idea. Better to attack an ion engine to an asteroid and drop THAT on the poles. Easier, cheaper, more effective.

even if we could do that then knowing our luck we'd probably knock the planet off its orbit and everything will go down the gurgler.. :rolleyes:

Why not just activate the ancient ice-melting machine that the ancestral martians left buried on the ground?

Jeez... always with the complicated ways you guys....

That could work too but I don't think they left us the spare key to start the bloody thing.. :p:lol:

Posted

Great! They find water on Mars. How about turning what ever tech try used towards California?

Seriously though, I think the significance here is less about colonizing and more about finding some sort of microscopic life. The last thing we need to do is nuke the place but of course it's the first thing we think of.

  • 2 weeks later...
Posted

Mars is awesome, as it's continually evolving our basic understanding of what can exist in different places.

Even salty water on the surface at all, is bloody amazing. There could be under ground caverns with flowing water, and even

algae using the core's warmth deep below.

If they can for sure find water, then they can harvest oxygen, and Carbon Dixoide which would make a manned mission

to mars last longer, and be much cheaper.

Posted

That would be awesome but watching The Martian, I kept thinking of how we'd just leave trash all over the place... lol.

Eh, the whole planet's already rusted to heck. The current residents aren't taking any better care of it.
  • 2 weeks later...
  • 4 weeks later...
Posted

The Sun still is mind blowing.. it's like ... just this sphere of nuclear reaction, that looks so calming from far, but far from calm.

I still have trouble just keeping how darn BIG the sun is in my head.
Posted

I still have trouble just keeping how darn BIG the sun is in my head.

... and red dwarfs aside, our sun is kind of a runt in comparison to some of the heavyweights in our Galaxy, which is a damned good thing.

46-betelgeuse-vs-sun.jpg

  • 3 weeks later...
  • 1 month later...
Posted

http://www.slate.com/blogs/bad_astronomy/2016/01/21/evidence_found_of_a_possible_planet_in_the_outer_solar_system.html is a good read that avoids the whole "WHOO PLANET X" hype train. There's strongly suggestive evidence for the existence of a planet, but as of yet, one has not been found. It is compellingly strong evidence, but until an object is observed, it's circumstantial.

It isn't the first time evidence has suggested a planet that didn't exist. Or vice-versa. We found Pluto through accident, as it happened to be where measurements implied a planet should be to account for variations in Neptune's orbit, but... those variations in Neptune's orbit were generated from bad measurements, Pluto wasn't actually big enough to cause them anyways, and it was sheer coincidence Pluto was in the sky at the place they were expecting to see a planet.

Not to be a wet blanket or anything, just... all the "we found a new planet" stuff is a bit premature. Moreso than when the news was labelling every new Kuiper Belt Object a new planet.

Also, one of the guys involved is the guy who got Pluto demoted FROM planet status. I find the irony amusing.

  • 3 weeks later...
Posted

Gravitational waves produced by the merger of two black holes, incidentally. The process converted three solar masses of matter into energy. That's a LOT of energy to hit spacetime all at once..

  • 2 weeks later...

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