Antimatter Propulsion

[dragoner]

Something that is rather cool: http://nextbigfuture.com/2015/10/positron-dynamics-plans-to-fly.html?m=1

 

[Reynard]

I'll put this on the shelf next to cold fusion and the working warp drive for now.

 

[dragoner]

This is more than just theory, if they are going into production; I'm more interested in combustion chamber specs.

 

[Tom Kalbfus]

Let me quote it here:

October 19, 2015
Positron Dynamics plans to fly an antimatter powered cubsat by 2019
In 2013, Positron Dynamics had seed funding from Paypal billionaire Peter Thiel’s Breakout Labs. Initial simulations show that as much as 10 micrograms of positrons could be produced each week with a linear accelerator," says co-founder Ryan Weed, PhD, a physicist and former cryogenic engineer for Jeff Bezos’s space flight company Blue Origin.

Now they have stated in a new presentation that they will have an antimatter powered cubesat vehicles in 2016-2019. They will be able to keep a cubesat in low earth orbit for seven years instead of few days. Then they will enable high speed spacecraft to go the outer solar system and then to the stars at a significant fraction of the speed of light

10 micrograms of positrons? How does one store positrons? A microgram is one billionth of a kilogram., and since a positron is a positively charged electron, it has the same mass as one. 9.11x10ˉ³¹kg. That is 10,976,948,408,342,480,790,340 positrons!

 

[Tom Kalbfus]

I'll put this on the shelf next to cold fusion and the working warp drive for now.

Warp drive requires negative mass, not antimatter, I think antimatter is easier to produce than a warp envelope!

 

[Reynard]

Warp drive require negative mass? What warp drives are those? Normally, warp drives are described as bending space so distance is shortened rather than a propulsion system pushing a vessel at FTL speeds. As Star Trek describes, matter-antimatter reactions are a power source for warp engines.

Normally the significance of antimatter is the tremendous energy produced by annihilation with equal amounts of matter. That could be what is being conceived as the reaction mass and is an 'antimatter' rocket and still isn't a warp engine. However check out the section labeled Difficulties with antimatter rockets:

https://en.wikipedia.org/wiki/Antimatter_rocket

Another big damper - "Scientists claim that antimatter is the costliest material to make. In 2006, Gerald Smith estimated $250 million could produce 10 milligrams of positrons (equivalent to $25 billion per gram); in 1999, NASA gave a figure of $62.5 trillion per gram of antihydrogen."

 

[Tom Kalbfus]

Warp drive require negative mass?

The Alcubierre warp drive.
The Alcubierre drive or Alcubierre warp drive (or Alcubierre metric, referring to metric tensor) is a speculative idea based on a solution of Einstein's field equations in general relativity as proposed by theoretical physicist Miguel Alcubierre, by which a spacecraft could achieve faster-than-light travel if a configurable energy-density field lower than that of vacuum (that is, negative mass) could be created.

Rather than exceeding the speed of light within a local reference frame, a spacecraft would traverse distances by contracting space in front of it and expanding space behind it, resulting in effective faster-than-light travel. Objects cannot accelerate to the speed of light within normal spacetime; instead, the Alcubierre drive shifts space around an object so that the object would arrive at its destination faster than light would in normal space.[1]

Although the metric proposed by Alcubierre is mathematically valid (in that the proposal is consistent with the Einstein field equations), it may not be physically meaningful, in which case a drive will not be possible. Even if it is physically meaningful, its mere existence does not necessarily mean that a drive can be constructed. The proposed mechanism of the Alcubierre drive implies a negative energy density and therefore requires exotic matter. So if exotic matter with the correct properties does not exist then the drive could not be constructed. However, at the close of his original paper[2] Alcubierre argued (following an argument developed by physicists analyzing traversable wormholes[3][4]) that the Casimir vacuum between parallel plates could fulfill the negative-energy requirement for the Alcubierre drive.

What warp drives are those? Normally, warp drives are described as bending space so distance is shortened rather than a propulsion system pushing a vessel at FTL speeds. As Star Trek describes, matter-antimatter reactions are a power source for warp engines.

To expand space behind the starship, and thus make it appear that the ship was traveling faster than light, you need negative mass to create a positive curvature of space, and a positive mass to create a negative curvature of space in front of the starship, which is similar to a black hole. As Einstein's equations states, mass is equal to energy, a negative mass requires negative energy to form, and you won't get energy directly by combining matter and antimatter. Antimatter is not really the opposite of matter, it is matter where the elementary charges of its subatimic particles are the opposite of normal matter, the opposite of matter is called exotic matter and it has negative mass, and is equal to negative energy.

Normally the significance of antimatter is the tremendous energy produced by annihilation with equal amounts of matter. That could be what is being conceived as the reaction mass and is an 'antimatter' rocket and still isn't a warp engine. However check out the section labeled Difficulties with antimatter rockets:

https://en.wikipedia.org/wiki/Antimatter_rocket

Another big damper - "Scientists claim that antimatter is the costliest material to make. In 2006, Gerald Smith estimated $250 million could produce 10 milligrams of positrons (equivalent to $25 billion per gram); in 1999, NASA gave a figure of $62.5 trillion per gram of antihydrogen."

I guess that's inflation!

 

[Condottiere]

So you pull it along, rather than push it.

 

[Tom Kalbfus]

So you pull it along, rather than push it.

A black hole by itself is not a warp drive, having the opposite of a black hole right next to it and placing the spaceship in between is what creates the warp envelope.