Infinity ship

[locustgate]

I have a question how feasible is a xenon propelled ship, i.o.w. how many engines would I need to propel a ship large ship.

Edited November 7, 2014 by locustgate

[Skorpychan]

Just one will propel it.

Please define what you want from the engines. What sort of TWR do you want? How big a ship? Define 'feasible'.

[Slam_Jones]

A single Ion engine will move anything (in space)

Beyond that, it's a matter of how long you want to babysit your burns. Less engines mean longer burns. More engines mean more power drain.

Personally, for anything beyond a probe, I use Ion engines as a secondary/emergency booster, due to the high efficiency. Using them as a main engine means it will take a very long time to get wherever you're trying to go.

[locustgate]

Just one will propel it.

Please define what you want from the engines. What sort of TWR do you want? How big a ship? Define 'feasible'.

Haven't got the size down yet but, 2 large batteries, a large RCS fuel, X large solar panels, a crew quarters, a docking hub, 2 medium batery, 1 ppd-12. Propel it faster than an hour burn, around single digit minute burn to any location.

I'm also using Karbonite but haven't gotten the hang of it so in case I can't get ions to work I'll use a collection probe to refuel.

[MarvinKitFox]

I have a question how feasible is a xenon propelled ship, i.o.w. how many engines would I need to propel a ship large ship.

For efficiency, the ideal count of Ion Engines is... one.

Even if your ship masses thousands of tons.

You may need to apply a modicum of patience when changing your orbit.

[locustgate]

For efficiency, the ideal count of Ion Engines is... one.

Even if your ship masses thousands of tons.

You may need to apply a modicum of patience when changing your orbit.

Depends your definition of modicum, my patient runs out after the double digits roll over.

[Skorpychan]

Haven't got the size down yet but, 2 large batteries, a large RCS fuel, X large solar panels, a crew quarters, a docking hub, 2 medium batery, 1 ppd-12. Propel it faster than an hour burn, around single digit minute burn to any location.

I'm also using Karbonite but haven't gotten the hang of it so in case I can't get ions to work I'll use a collection probe to refuel.

You would need ridiculous amounts of ion engines to get that sort of TWR. Consider nuclear rocket motors instead.

[Starman4308]

For efficiency, the ideal count of Ion Engines is... one.

Even if your ship masses thousands of tons.

You may need to apply a modicum of patience when changing your orbit.

A nitpick: in theory, if it was necessary to transfer in a single orbit, the Oberth effect might favor multiple ion engines.

Point remains though: for maximum delta-V, the ideal configuration for anything is a single ion engine and enough asparagus to feed China for a year.

EDIT: I'll assume 5 minutes to cover the 950 m/s to get to Kerbin escape velocity. That requires 3.167 m/s^2 of acceleration. Ignoring fuel loss, your craft would have to be 39.6% ion engines to achieve this sort of acceleration. In reality, that would go down because acceleration goes up as you lose fuel, but it amply demonstrates that, if you want ion propulsion, you are going to have to live with very, very slow transfers. Consider using 4x physics acceleration. The key binding is 'mod-.'; for Windows, mod- is the alt key, for Linux, right-shift, for Apple, I'm not sure.

Edited November 7, 2014 by Starman4308

[MarvinKitFox]

.... a single ion engine and enough asparagus to feed China for a year.

Hmm. apparently linguini con funghi porcini can be cleaned off from a computer monitor quite easily.

Thank you for that info.

[Skorpychan]

Hmm. apparently linguini con funghi porcini can be cleaned off from a computer monitor quite easily.

Thank you for that info.

Asparagus staging.

[Hodo]

I have a question how feasible is a xenon propelled ship, i.o.w. how many engines would I need to propel a ship large ship.

This was a design I came up with a long time ago for a challenge. It was a mediocre success.

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It was powered by a bunch of ion engines with a backup orbital burn drive of 3 nukes.

I think it had a total of 10km/s delta velocity on ions alone and another 4.5km/s with nukes.

[Jouni]

My ion-powered Moho ship had 12 engines for about 40 tonnes of mass.

Its design was based on the idea that you rarely need full thrust for extended periods of time. Instead of building big ugly solar panel contraptions to supply enough power to the engines, you can use a pile of batteries and less solar panels.

[Boomerang]

A nitpick: in theory, if it was necessary to transfer in a single orbit, the Oberth effect might favor multiple ion engines.

Point remains though: for maximum delta-V, the ideal configuration for anything is a single ion engine and enough asparagus to feed China for a year.

EDIT: I'll assume 5 minutes to cover the 950 m/s to get to Kerbin escape velocity. That requires 3.167 m/s^2 of acceleration. Ignoring fuel loss, your craft would have to be 39.6% ion engines to achieve this sort of acceleration. In reality, that would go down because acceleration goes up as you lose fuel, but it amply demonstrates that, if you want ion propulsion, you are going to have to live with very, very slow transfers. Consider using 4x physics acceleration. The key binding is 'mod-.'; for Windows, mod- is the alt key, for Linux, right-shift, for Apple, I'm not sure.

It's Alt/Option on OSX as well.