China's Space Agency is claiming successful test of EM Drive

[Werthead]

It doesn't allow travel past lightspeed. That's the Alcubierre Drive, which really is in the realm of fantasy until NASA can make it work, which we're probably a century or two away from even testing. One slight issue at the moment is that even if the thing works, it builds up a colossal amount of energy in front of the ship so 1) you can't see where the hell you're going and 2) the second you arrive at your destination and slow down, the energy keeps travelling in a straight line and obliterates everything in front of you.

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Assuming, for the sake of argument, that the EM drive really is completely above board, the answer is still no. At least at the moment it is. The demonstrated thrust is tiny, significantly weaker even than current ion drives. The hardest part of any large space project is getting things into orbit in the first place and for that you need very powerful engines.

The EM thrust effect makes this thing only cost-effective for real long-range journeys, like to Neptune and back. It's certainly useless for getting to Mars, as it's way too slow. It may have some applications as an emergency backup drive, though.

The Epstein Drive allows ships to accelerate to significantly high velocities (an appreciable fraction of c) and allow transits across the Solar system in months rather than years. When the planets are close enough, you can travel from Earth to Mars in days rather than weeks, and from Earth to Jupiter in weeks rather than months. Which is cool, but still completely outside our technology for the forseeable future.

Honestly, people should be getting more excited about Hawking's lightsail probe project to Alpha Centauri, which is based on existing theories and existing technologies, it just needs the cost of production to come down a bit more.

[Ser Scot A Ellison]

3 hours ago, Werthead said:

It doesn't allow travel past lightspeed. That's the Alcubierre Drive, which really is in the realm of fantasy until NASA can make it work, which we're probably a century or two away from even testing. One slight issue at the moment is that even if the thing works, it builds up a colossal amount of energy in front of the ship so 1) you can't see where the hell you're going and 2) the second you arrive at your destination and slow down, the energy keeps travelling in a straight line and obliterates everything in front of you.

The EM thrust effect makes this thing only cost-effective for real long-range journeys, like to Neptune and back. It's certainly useless for getting to Mars, as it's way too slow. It may have some applications as an emergency backup drive, though.

The Epstein Drive allows ships to accelerate to significantly high velocities (an appreciable fraction of c) and allow transits across the Solar system in months rather than years. When the planets are close enough, you can travel from Earth to Mars in days rather than weeks, and from Earth to Jupiter in weeks rather than months. Which is cool, but still completely outside our technology for the forseeable future.

Honestly, people should be getting more excited about Hawking's lightsail probe project to Alpha Centauri, which is based on existing theories and existing technologies, it just needs the cost of production to come down a bit more.

If there is a means for generating thrust that doesn't require propellant then that makes travel to distant locales significantly easier.  Fuel is a huge portion of the mass required in designing any space vessel.

[Free Northman Reborn]

10 hours ago, Werthead said:

It doesn't allow travel past lightspeed. That's the Alcubierre Drive, which really is in the realm of fantasy until NASA can make it work, which we're probably a century or two away from even testing. One slight issue at the moment is that even if the thing works, it builds up a colossal amount of energy in front of the ship so 1) you can't see where the hell you're going and 2) the second you arrive at your destination and slow down, the energy keeps travelling in a straight line and obliterates everything in front of you.

The EM thrust effect makes this thing only cost-effective for real long-range journeys, like to Neptune and back. It's certainly useless for getting to Mars, as it's way too slow. It may have some applications as an emergency backup drive, though.

The Epstein Drive allows ships to accelerate to significantly high velocities (an appreciable fraction of c) and allow transits across the Solar system in months rather than years. When the planets are close enough, you can travel from Earth to Mars in days rather than weeks, and from Earth to Jupiter in weeks rather than months. Which is cool, but still completely outside our technology for the forseeable future.

Honestly, people should be getting more excited about Hawking's lightsail probe project to Alpha Centauri, which is based on existing theories and existing technologies, it just needs the cost of production to come down a bit more.

The implications of a propellantless thruster are actually rather profound. I know you are merely dispelling the common misconception that this is NASA's infamous so-called "warp drive", which indeed, the EMDrive/Mach Effect thruster has no relation to at all. (Although the second mathematical derivation of the Mach Effect Thruster does indeed propose Warp Drive-like effects, but that is not the version that is being tested now).

In any case, if a propellantless thruster truly is perfected, it indeed opens up the galaxy to us, even though light speed is never exceeded. A propellantless thruster allows constant acceleration, and if you are able to generate constant acceleration of 1g, for example, you can reach the Centauri system in only 5 years. And due to relativistic effects, it would be even less time from the perspective of the ship's crew.

In fact, at 1g constant acceleration, you can pretty much cross the entire galaxy in a human lifetime, from the perspective of the ship's crew, even though more than 100,000 years would pass from an outside perspective.

In any case, 5-year real time trips between star systems opens up the entire galaxy to us. Within a few centuries, human civilization could spread to thousands of worlds.

[Werthead]

9 hours ago, Free Northman Reborn said:

The implications of a propellantless thruster are actually rather profound. I know you are merely dispelling the common misconception that this is NASA's infamous so-called "warp drive", which indeed, the EMDrive/Mach Effect thruster has no relation to at all. (Although the second mathematical derivation of the Mach Effect Thruster does indeed propose Warp Drive-like effects, but that is not the version that is being tested now).

In any case, if a propellantless thruster truly is perfected, it indeed opens up the galaxy to us, even though light speed is never exceeded. A propellantless thruster allows constant acceleration, and if you are able to generate constant acceleration of 1g, for example, you can reach the Centauri system in only 5 years. And due to relativistic effects, it would be even less time from the perspective of the ship's crew.

In fact, at 1g constant acceleration, you can pretty much cross the entire galaxy in a human lifetime, from the perspective of the ship's crew, even though more than 100,000 years would pass from an outside perspective.

In any case, 5-year real time trips between star systems opens up the entire galaxy to us. Within a few centuries, human civilization could spread to thousands of worlds.

At constant 1g constant acceleration you can cross (and probably outlast) the entire observable universe within a human lifespan.

[JGP]

On 12/28/2016 at 6:15 PM, Werthead said:

It doesn't allow travel past lightspeed. That's the Alcubierre Drive, which really is in the realm of fantasy until NASA can make it work, which we're probably a century or two away from even testing. One slight issue at the moment is that even if the thing works, it builds up a colossal amount of energy in front of the ship so 1) you can't see where the hell you're going and 2) the second you arrive at your destination and slow down, the energy keeps travelling in a straight line and obliterates everything in front of you.

Uhm... w0t. The Alcubierre Drive will remain in the realm of fantasy, NASA or no. Regardless, re: the bolded part? How do you figure?

 

*edited for spelling

[JGP]

On 12/27/2016 at 5:30 PM, Relic said:

I'd take a few years of indentured service to have a couple mysteries of the comos revealed to me, personally. 

Well, when you put it like that. But what if if they want you to blandarp with their fleerd'eh defleur? [shudders]

 

[Werthead]

12 hours ago, JEORDHl said:

Uhm... w0t. The Alcubierre Drive will remain in the realm of fantasy, NASA or no. Regardless, re: the bolded part? How do you figure?

It's not completely impossible, just mind-bogglingly unlikely due to various issues such as expense and it relies on the existence of exotic matter with properties that have not yet actually been discovered. Interestingly, most of the problems accrue at superluminal speeds: the drive becomes much more viable when you use it instead to accelerate very quickly and at a relative energy-efficient rate to say 99% of lightspeed but stay subluminal.

As for the the wavefront problem, travelling at superluminal velocities would build up colossal amounts of Hawking radiation. When the vessel dropped out of warp, this would "pop" the Alcubierre bubble, with a resulting shockwave travelling outwards. In the case of the front of the ship, it would destroy anything in front of it in a blaze of radiation.

[Larry of the Lawn]

Totally ignorant of most of the math here, how long would it take to attain, say, 50% of c at an acceleration that would be survivable for a manned flight?  

[Ded As Ned]

I personally find decelerating at your distant destination to be a much bigger problem to solve than accelerating to get there.  Even the proposed Alpha Centauri project would just be a fly-by.  No stopping to look around.

So even if we had the technology to achieve such sustained acceleration, half of the trip is going to be spent slowing back down, adding considerable time to the journey.  

[Ser Scot A Ellison]

LtI,

Here are some answers to your 1g acceleration question:

http://space.stackexchange.com/questions/840/how-fast-will-1g-get-you-there

[Free Northman Reborn]

3 hours ago, Ded As Ned said:

I personally find decelerating at your distant destination to be a much bigger problem to solve than accelerating to get there.  Even the proposed Alpha Centauri project would just be a fly-by.  No stopping to look around.

So even if we had the technology to achieve such sustained acceleration, half of the trip is going to be spent slowing back down, adding considerable time to the journey.  

Well, the 5 year trip to Centauri provides for accelerating for half the trip and decelerating for the 2nd half. So you come to a dead stop at your destination. And all the while you have nice 1G earth gravity for the crew, due to the 1G acceleration.

[Larry of the Lawn]

3 hours ago, Ser Scot A Ellison said:

LtI,

Here are some answers to your 1g acceleration question:

http://space.stackexchange.com/questions/840/how-fast-will-1g-get-you-there

Thanks! 

[Ded As Ned]

1 hour ago, Free Northman Reborn said:

Well, the 5 year trip to Centauri provides for accelerating for half the trip and decelerating for the 2nd half. So you come to a dead stop at your destination. And all the while you have nice 1G earth gravity for the crew, due to the 1G acceleration.

Link?  Maybe we're talking about different projects... The project I'm thinking of is the one backed by the Russian billionaire for a flyby with microsatellites to gather data while they pass through Alpha Centauri, but that's it.

Not to say it isn't exciting.

[Mudguard]

I can't get excited about the EM drive and the other crazy drives like it that violate the known laws of physics.  It's like cold fusion.  All hype, but no credible data.  Doubt that we'll get that here.

[Liffguard]

3 hours ago, Free Northman Reborn said:

Well, the 5 year trip to Centauri provides for accelerating for half the trip and decelerating for the 2nd half. So you come to a dead stop at your destination. And all the while you have nice 1G earth gravity for the crew, due to the 1G acceleration.

Well, not a dead stop. Presumably you want to be in orbit around your target when you get there. At a minimum you just need to get below escape velocity.

 

I can't get excited about the EM drive and the other crazy drives like it that violate the known laws of physics.  It's like cold fusion.  All hype, but no credible data.  Doubt that we'll get that here.

I'm getting the same feeling as the supposedly superluminal neutrinos from a few years ago. Turned out to be a measuring problem.