Space planes make rockets obsolete

[rkman]

Just as it would in reality if we'd have developed space plane technology; the entire point is that space planes are (would be) more efficient than rockets (specifically wrt launching from planets with an atmosphere).

So once we have space planes there is no reason to use rockets, just as there not much reason to use cart-and-horse since we have cars.

The only thing holding people back to not use any rockets at all is part-count and associated low frame rate.

In my opinion it would be sad if a game that is supposed to be a rocket building game becomes a space plane building game.

One way to save ksp from this scenario is to have space plane technology very late in the tech tree and give its parts a financial cost much higher than rocket technology. Although that would have no affect on sand-box mode.

[Fulbert]

Space planes are also harder to build, launch and land, and they are not really reusable from the gameplay standpoint since a craft is effectively destroyed anyway when it's recovered. I won't deny building a successful space plane design is a very satisfying achievement, but really I believe they have mostly the roleplay value right now.

[Einsty]

Space planes are also harder to build, launch and land, and they are not really reusable from the gameplay standpoint since a craft is effectively destroyed anyway when it's recovered. I won't deny building a successful space plane design is a very satisfying achievement, but really I believe they have mostly the roleplay value right now.

I believe the plan is to add parts that survived the flight into stock when they are recovered. Ammount in stock is displayed next to part cost, so they do not exactly get destroyed.

As Fulbert mentioned, rocket is easier to design and current set of in-game assets allows for relatively big yet stable contraptions, like lifting an entire space station on one go, something much more difficult when using space planes.

Also, once economy and budgets are introduced, spaceplanes won't be that attractive in the early game.

But who knows, they should both be equaly possible opportunities for players.

"We're throwing science at the wall to see what sticks." --Cave Johnson, Aperture Science CEO

[Captain Sierra]

Spaceplanes are a high-skill build. Payload carrying spaceplanes even moreso. Also, when comparing in the real world (Skylon vs Falcon family), rockets are less complex. Though the efficiency may not be there, it's a lot easier to build an SLS than it is to build something like Spaceship One that can carry the same weight. There is a reason we went to the moon with a giant rocket and not a huge plane.

[rkman]

I believe they have mostly the roleplay value right now.

It does, but that's probably not how it will be in the finished game, and that's where my concern is.

Spaceplanes are a high-skill build. Payload carrying spaceplanes even moreso. Also, when comparing in the real world (Skylon vs Falcon family), rockets are less complex. Though the efficiency may not be there, it's a lot easier to build an SLS than it is to build something like Spaceship One that can carry the same weight. There is a reason we went to the moon with a giant rocket and not a huge plane.

That's all true for the real world because we do not have fully developed space plane technology. But in ksp we do.

So what's true for real world space planes is not necessarily true in ksp.

In ksp it works and that means a space plane can do the same mission that a rocket can do, but with considerably lower launch mass, in other words: considerably higher efficiency.

I figure the maximum size/mass of a ksp space plane is in fact smaller than that of a rocket, but it seems the vast majority of missions (normal missions, excluding things like launching complete ISS-like structures) can be done with space planes more efficiently than with rockets.

I am the sort of player who at least tries to make efficient designs, so i would go for space planes if i weren't role-playing that ksp has no fully developed space plane technology because i want it to be a game about rockets, not a game about space planes.

[crazyewok]

When they bring in money Im guessing reuseablity will be a BIG concern.

[Ravenchant]

This may very well be true for satellites or smaller station components. But getting 50 or 100 tons into orbit with a plane? Anyone who manages that deserves an applause. For everyone else, there are rockets

[jwenting]

space planes are more expensive to build, maintain, and fly than are rockets, require a lot more fuel per pound of payload to orbit, and thus are less economical as fuel is the main cost of rockets.

A 2 stage to orbit system with both stages fully reusable might be a proper alternative, the first stage of which could be an aircraft like structure.

Or maybe a 3 stage, with 2 aircraft like stages.

But that increases complexity enormously, making the contraption more expensive, more prone to failure, and heavier.

[rkman]

When they bring in money Im guessing reuseablity will be a BIG concern.

Even more reason to use space planes.

This may very well be true for satellites or smaller station components. But getting 50 or 100 tons into orbit with a plane? Anyone who manages that deserves an applause. For everyone else, there are rockets

I'm pretty sure people are using space planes to do manned science return missions to Eve and Joolian moons.

[Captain Sierra]

I'd like to point out that though generaly more efficient than rockets, spaceplanes are not the best way to lift weight. It takes some serious over-engineering to do it.

http://forum.kerbalspaceprogram.com/threads/56621-The-Wrong-Brothers-career-mode-done-differently-%28pic-heavy%29?p=836490&viewfull=1#post836490

That is what it takes to lift 23 tons. Yeah, you can get a plane all the way to lathe and back single staged, but payloads? not without some serious work (and possibly lots of clipping).

[Themohawkninja]

Just as it would in reality if we'd have developed space plane technology; the entire point is that space planes are (would be) more efficient than rockets (specifically wrt launching from planets with an atmosphere).

Which they aren't due to already-put-in-place balancing reasons.

So once we have space planes there is no reason to use rockets, just as there not much reason to use cart-and-horse since we have cars.

Rockets are easier to launch, control, and hold more payload (unless you want an absurdly huge spaceplane).

The only thing holding people back to not use any rockets at all is part-count and associated low frame rate.

I'd say the skill needed to make one more so than anything else.

In my opinion it would be sad if a game that is supposed to be a rocket building game becomes a space plane building game.

Well, it's not going to go that way.

One way to save ksp from this scenario is to have space plane technology very late in the tech tree and give its parts a financial cost much higher than rocket technology. Although that would have no affect on sand-box mode.

Already done. The plane parts are late in the tech tree as of right now.

[Ravenchant]

That is what it takes to lift 23 tons.

23 tons of plane + lander, and another 20 tons of pure, concentrated coolness. Anyway, the design doesn't look that heavy (assuming a 15% payload ratio for a rocket, you'd need 153 tons). A worse shortcoming would be that the payload must be precisely tailored to the lifter, unless you want to keep designing it from scratch each time

[FenrirWolf]

I don't really see this happening. Reusability of spaceplanes is a major plus for them, but they require a major investment in time and effort to make functional. They are more specific on the shapes and sizes of deliverable payloads as well.

It is worth noting that reusable vehicles is not the only paradigm for cost-efficient spaceflight in the real world either. Depending on how part costs vs. reusability savings work out, it could still be cheaper to use Big Dumb Boosters if your goals are better serviced by that model.

http://en.wikipedia.org/wiki/Big_dumb_booster

[rkman]

That is what it takes to lift 23 tons.

That is impressive. Any idea what the mass of the ssto transporter is?

I suppose that question has been answered: 20 tons, a fraction of what a rocket for the same payload mass would be.

Which supports the point i am trying to make. Otoh i now realize that building such large space planes does take quite a lot of effort.

Regarding the techtree: i'd hope that in the final game the techtree does not only serve as a tutorial, but plays an important role until late in career mode. Imo spaceplane tech should not be available in the tutorial but late in career mode.

Edited January 6, 2014 by rkman