Anti-matter engines

As i mentioned before Star Trek is the closest thing i have to knowledge about the solar system. It really caught my interests when i learned of ideas and theories regarding Anti-matter for engines. A scientest by the name of Iddo Genuth, working for positronic research LLC, is researching with NASA the idea of a positronic engine using positrons as a propulsion system. positrons are the anti-particle of an electron. 10 mg of this has the energe of 428 tons of TNT. There are currently 3 ideas for a positronic engine system.

1. Solid core - Energy is transferred to a propellant in tungsten metal matrix heated by annihilation gamma rays.

Advantages - Well understood technology.
Disadvantages - Performance limited by melting temperature of tungsten.

2. Gas core - Energy is transferred to liquid/gas propellant directly heated by annihilation gamma rays.

Advantages - Improvement over solid core, not limited by melting temperature.
Disadvantages - Flowing multi-fluid is unstable at boundaries, may ionize and create plasma.

3. Solid Ablation - Energy is transferred to a material that ablates off surface of a pusher plate.

Advantages - Simplicity in design, no obvious technology limits.
Disadvantages - Half of the gamma rays do not strike the pusher plate, maximum efficiency 50%. ( found in an article [33] by the future of things)

These ideas seem very ambitious but look to be a great oppurtunity for Intergalatic travel. Positrons are created by a colider and currently to get 10 mg ( estimated amount for mars mission) it would take 5 years after builiding a $1.5 billion acceleration plant. no matter how you swing it, intergalactic travel isn't going to be cheap. holding this anti-matter is another problem that has already been solved by the research team. to hold the anti-matter, they have proposed a neutrel charged positronium after being stabelized in magnetic fields. IN other words a big tank using a magnetic field and other stablized antimatter to sustain the energy of the positrons.

Fusion Rockets.

Our current space program uses Liquid Rocket fuel to propel us into outer space. When dealing with interstellar travel, this form of transportation is impossible and hugely inefficient. one of the options i have talked about before was space sails using lasers and the sun to propel it. Another option is Fusion. We all know of the devastating effects of the Hydrogen bomb and the atom bomb, but recently scientist's are researching a way to turn this into a feasible way of transportation. Hydrogen is the preferred method of transportation since a ship could refuel in space since hydrogen is plentiful. this could reduce the amount of time to reach mars by 50%! fusion generated propulsion could generate up to 300 times the impulse of that of a current chemical rocket. The VASIMAR engine currently gives us a look at how the fusion engine creating plasma could work.
Forward cell - The propellant gas, typically hydrogen, is injected into this cell and ionized to create plasma.

Central cell - This cell acts as an amplifier to further heat the plasma with electromagnetic energy. Radio waves are used to add energy to the plasma, similar to how a microwave oven works.

Aft cell - A magnetic nozzle converts the energy of the plasma into velocity of the jet exhaust. The magnetic field that is used to expel the plasma also protects the spacecraft because it keeps the plasma from touching the shell of the spacecraft. Plasma would likely destroy any material it came in contact with. The temperature of the plasma exiting the nozzle is as hot as 180 million degrees Fahrenheit (100 million degrees Celsius). That's 25,000 times hotter than gases expelled from the space shuttle ( Article from Kevin Bosnor).
Going to mars would be great a great challenge for the earth to undertake, but a challenge i'm afraid that would take take great co-operation on all nations. An undertaking like this could do more then get to us to mars and advance our science, it could unite the nations under one common goal.

Sails in outerspace?

As I researched this topic, I came across an article by one Chuck Rahls. He spoke of three theories on interstellar travel. one is Anti-matter (I'm assuming similar to that of the USS Enterprise), another is fusion, and the last space sails. According to Chuck, Space sails are the most technologically viable solution at this time. Upon reading this i said "pfft ya right what are we going to do ride sound waves" thinking i new something about space and its emptiness. after I continued to read i noticed my ignorance as he laid the theoretical option out. The sails on this craft would be enormous and made out of super thin yet sturdy material like Mylar. this material also has to be reflective because it would be depending on contact of protons from the sun which would be similar to a small push for a Long time. this means that there is no max velocity it can simply keep going faster. the dimensions of the sail depend on the weight. If for say the weight is 16 grams, then you would need 1 km of sail. to steer it huge lasers would be used amounting to about 10 gigawatts shining on the entire length. As i continued to read i became even more intrigued wondering how much it would take to send say a one ton space craft. the answer depressed me, we would need 1000 km's of sail with 10 million gigawatts of laser energy ( about 3x that the earth uses now). I guess for now we will have to stick to the bare minimum when traveling to other stars. A small craft like this could reach the closest star to us in 10 years. look out Proxima Centari here we come!