If we had faster engines, how do we go to other planets/stars?

[lyndonguitar]

and so I was reading about this http://en.wikipedia.org/wiki/Antimatter_rocket and this http://www.dailytech.com/Earths+Dirty+Secret+Our+Magnetic+Field+Traps+Antimatter/article22375.htm

and many other anti-matter related things and found out that it is very much plausible to do.

However things brings me to a question, If we had faster propulsion techniques, how would we travel? What's the best method?

1. Could we just burn straight up?

2. Burn more delta-v and thus making a wider hyperbolic trajecjory, significantly reducing travel time?

3. Just burn normally? and hope to conserve as much fuel as possible to reduce fuel mass but also increase travel time(or just the same as using conventional rockets)

4. or what?

In that wiki link it is stated that "Most proposed antimatter rocket designs require a large amount of antimatter (around 10 grams to reach Mars in one month)", so if they had 10 grams of antimatter and a capable rocket,

what maneuver would they do to reach mars in one month? (normally it takes 8-10 months to go there)

Edited May 12, 2013 by lyndonguitar

[nyrath]

If your propulsion system has lots of thrust and delta V, you have a Torchship, and should use a Brachistochrone trajectory.

This is when you aim your rocket at your destination, continuously accelerate until you are half-way, flip over so your tail is pointed at your destination, then decelerate until you match velocity with your destination.

http://www.projectrho.com/public_html/rocket/torchships.php

[Cocoon90]

The best method should be by taking advantage of wormhole, but nobody knows if they can really exist or not. Nuclear fusion would be a good alternative, fuel wouldn't be burnt all at once but a series of micro nuclear explosions would give the spaceship enough thrust to reach impressive speeds using just Hydrogen isotopes as fuel since it's the most abundant element in the universe. Antimatter in my opinion would be a better resource, ok, since the collision between matter and antimatter provides bigger amounts of energy than nuclear fusion, but at this moment even 10 grams of antimatter is an amount way beyond our capabilities. Only a few years ago (2 or 3) CERN recreated a few hundreds of atoms of anti Hydrogen. To achieve 10 grams it takes too much time, power, and the cost would be unsustainable. As nyrath said, half of the fuel would be spent for "breaking", and the maneuver would be similar to that on that you plan in KSP. Not exactly but this is the idea..

I'm not saying that it wouldn't be possible thou.. At this moment best ways to travel long distances are plasma thrusters like the VASIMR, the solar sail or fusion engines (even if the last one is just a short term theory). I know nasa is working on a solar sail of the dimension of few squared meters, with the goal to make a squared kilometer one; the best method to burn fuel is to burn intermittently the fuel as some hall thrust ion engines do, at 50 - 60 hz, which is proven to save some fuel over time and to travel longer distances, instead of burning the fuel as a SRB or a liquid fuel rocket does. Try to search something in the JPL archives. You might find something useful.

[palioxis1248]

If your propulsion system has lots of thrust and delta V, you have a Torchship, and should use a Brachistochrone trajectory.

This is when you aim your rocket at your destination, continuously accelerate until you are half-way, flip over so your tail is pointed at your destination, then decelerate until you match velocity with your destination.

http://www.projectrho.com/public_html/rocket/torchships.php

^This.

You should go read his website.

[Brotoro]

Depends on how much antimatter costs.

[TheDarkStar]

Depends on how much antimatter costs.

Currently? A world-bankrupting amount per gram.

In the future? That depends entirely on whether or not we can mass produce it.

[Brotoro]

And the best trajectory to use will depend on the cost of the antimatter. It's a trade off of fuel vs. time.

[jwenting]

The best method should be by taking advantage of wormhole, but nobody knows if they can really exist or not.

and nobody knows if if they exist they would indeed do what you suggest they could do...

Wormholes as gateways between distant places are science fiction, pure and simple.

Even were they to exist, and were they to work as gates, and were there a way to build a ship that could enter and exit one without being spaghetified and destroyed, there's still no way we could create them between specific places of our own choosing.

[shynung]

Antimatter particles are very expensive. Anything using it for fuel would have been limited by funding to carry only small amounts. Fusion rockets and electric propulsion systems ran into similar problems, which is the available quantity of energy immediately usable.

Propulsion systems almost always trade one performance for another. Either it would be very efficient (high specific impulse), or very powerful (high thrust-to-weight ratio). If both parameters are high, there's usually another drawback (antimatter rockets using expensive fuels, nuclear pulse propulsion giving the payload rough impulses rather than a gentle push). Also, some propulsion systems cannot (or isn't allowed to) be used on Earth, for various safety reasons.

Most likely, standard Hohmann transfers would still be widely used.

[MrZayas1]

If we wanted to use this in a smaller scale, yesterday using the mods DeadlyReentry, and TAC life support mod i ran into a problem transferring inbetween Minmus and Mun. What happened was i was low in the tech tree, only batteries. So i ran out of electric charge about halfway to Minmus, and had plenty of delta V so this is what i did. I cancelled my orbital velocity to about 0 m/s, and then I burned straight towards Earth. What happened was i had the pod left, but the kerbal experienced so much g-force that he died in reentry. So i reverted and here was my solution. I had to burn in such a way that i enter the atmosphere at a shallower angle so that I spread out the g-forces into the reentry and i received a slower entry so that I could actually survive the fall. So luckily i got back to kerbin in time.

The practical use for this thread is that you could, potentially do this to achieve interplanetary travel, but one problem is that you would have to aerobrake into an extremely dense atmosphere in order to save the delta V that you would use to slow your velocity into an orbit around a planet. The same problem is that you would experience the g-forces associated with entering the atmosphere of said planet (Jool for example) and travelling at over 4 km/s would most likely kill you. So yes, it is probably possible, but your reentry would have to be extremely shallow to do this from interplanetary speed, and would require a pretty dense atmosphere. For instance, if I were to reenter kerbin at around 4 km/s the reentry (shallow) would probably only slow me down to 1200-2000 m/s and that is alot for a parachute to handle before it lands. Hopefully this gives a little insight on how that would work in real life, or at least KSP!