Yet Another Idea: My Three-Stage-To-Orbit Idea

[MedwedianPresident]

Three-Stage-To-Orbit Concept

This is my concept on a reusable three-stage-to-orbit system that can bring small and medium payloads into space.

FIRST STAGE

A high-power hypersonic aircraft (XB-70 style) that can safely reach an altitude of 20+ kilometres and speeds of more than 1000 meters per second. It should be able to carry large payloads. It takes off and accelerates and gains altitude over the ocean.

SECOND STAGE

The second stage is a winged Jumbo tank with a cluster of 4 high-power rocket engines (that are covered in fairings that are separated prior to engine ignition as an aesthetic element) that is separated from the hypersonic aircraft it is mounted on when it reaches maximum altitude and speed, bearing the third stage and accelerating it to a ballistic trajectory. It should be capable of landing after releasing the payload.

THIRD STAGE

The third stage is mounted on the second stage and is either a small spaceplane or a rocket stage with a small payload such as a satellite and a kick stage; it only needs a small delta-V because it just circularises the orbit.

[Sirrobert]

You can skip the 2nd stage if you turn the plane into a spaceplane. Dip out of the atmosphere with the plane, disconnect the payload, and circulize with the payload. Than land the plane as it dips back intop the atmosphere

[MedwedianPresident]

Yes, there are planned suborbital launch platform concepts. But my idea is to use 3 stages so that the first stage can be one of the hypersonic bombers you created.

Anyways, here's a illustration:

[KvickFlygarn87]

CoM misalignments?

Also, dem paint skillz.

[MedwedianPresident]

The CoM could be arranged so that every time a stage is separated it moves to the middle.

The CoT problem (especially on Stage 2) could be solved by tilting the engines several degrees downwards - this would also create some vertical thrust. Obviously, the rocket also will include ASAS to help kill any CoT or CoM problems.

[Claw]

Is this sort of what you're talking about? This one is only two stage, but your idea is possible to design.

Just have to be careful about where you release and how you fly. The carrier risks being deleted if it's too low in the atmosphere when the payload runs away from it.

Javascript is disabled. View full album

[MedwedianPresident]

The hypersonic aircraft is not surviving.

The second stage is surviving because it places you onto a suborbital trajectory. While you circularise, it just shouldn't get back into the atmosphere. When you've finished circularising, you can land the booster.

[maccollo]

I tried this in the real solar system...

I failed XD

[Random Tank]

This sounds very similar to Virgin Galactic...

Actually, using their method would probably better; I like the idea of your method, but you have a big (abeforementioned) problem with the CoM vs CoT, and purely the fact that a plane to carry all that will be HUGE! (and super clunky). Honestly, its much simpler/easier/more sensible/cheaper/faster/easier/lighter to have an SSTO or 2STO and refuel it in orbit; my shuttle/cargo transporter (ferries KAS parts) has a single engine and 6/8 intakes and will get to the Mun by itself! With some trust control its turbojet can still be producing thrust at ~38km, which can give me a periapsis without even using rockets!

As awesome as your idea would be, it would be too impractical to pull off; plus the Hypersonic Launch Plat. and the booster would die in the atmosphere

[UmbralRaptor]

Delete stage 2, integrate stage 3 with 1. Stock jets are good enough to get you into 75 x 30 km orbits.

[Armchair Rocket Scientist]

Yes, there are planned suborbital launch platform concepts. But my idea is to use 3 stages so that the first stage can be one of the hypersonic bombers you created.

Anyways, here's a illustration:

http://i.imgur.com/GExgMxJ.png

I didn't do this exact design, but I did once try to make an Air Launch to Orbit vehicle. Let me tell you, it's hard. First of all, your 1st stage has to be flyable with or without a huge rocket sitting on top of it, and has to be flyable in a wide range of conditions ranging from sea level and subsonic to Kerbin's upper stratosphere at mach 3+. This means that your Center of Mass, Center of Lift, Center of Thrust, and Center of Drag have to be aligned in all those conditions. In addition, your second stage appears to need to be flyable on its own. Your second stage is even worse off, as it will have to deal with asymmetric thrust with no air to make control surfaces work.

Anyway, in stock or FAR KSP, your idea should probably work fine without the kick stage: if you can get up to 1000 m/s and 20 km on your first stage, a single rocket-powered stage should be plenty to get you into orbit. However, your payload fraction will probably be lower than that of a well-designed SSTO, and possibly even harder to build. If you can get your first stage up to hypersonic speeds (1700+ m/s), you might be able to push the payload into a high enough suborbital trajectory that your second stage can use a nuclear engine.

For reference, here's what I built:

It does technically work, but it needs two B9 VTOL engines in the tail to keep the nose up at high altitude despite my best efforts to balance it. Its payload fraction is only 15%. There are SSTOs out there with payload fractions of 30%.

Anyway, a good source of advice might be the people who build shuttles. After all, an air-launched rocket is kinda like a shuttle in reverse if you think about it.

[Red Iron Crown]

I don't think the first stage will be recoverable. It could be in real life, but not in KSP because of limitations on when you can switch craft.

If you're interested in making a fully reusable craft in KSP, you really need to make it all one stage, or have the stage separation after circularization.

[Sirrobert]

Yes, there are planned suborbital launch platform concepts. But my idea is to use 3 stages so that the first stage can be one of the hypersonic bombers you created.

Anyways, here's a illustration:

http://i.imgur.com/GExgMxJ.png

Yes, and I meant that you can combine stage 1 and stage 2, into a plane with rocket engine (or use the RAPIER).

Basicly you'd turn the plane (which can go fast enough already) into an SSTO.

Shoudn't be to dificult if it can go hypersconic with that payload already

[MedwedianPresident]

I am planning for Stage 2 will be recoverable as it will reach a suborbital trajectory. As i said before, i quickly circularise before Stage 2 touches atmo and then i land Stage 2.

[UmbralRaptor]

It's still overcomplicated, and with KSP's limitations will make stage 1 expendable.

[Claw]

Well, making a piggyback space plane carrier is possible in stock, and the first stage can be recoverable (as I reference the scorpion on the previous page).

Two ways to manage it. You can establish the rocket stage on a suborbital ascent path, then keep flying the first stage after separation is more than 2.5km. Or you can fly the rocket portion a bit longer (outside of 2.5km) and make sure you switch back to the first stage before it descends below 23km (so you have buffer before it deletes). Craft can be in the atmosphere, just not too low.

Anyway, I chose to set the rocket/payload on a suborbital trajectory, then let it fly out of physics range while recovering the first stage. Then you can switch back to the rocket portion and establish orbit. This was the least risky for my carrier plane.

Sure, this is going to depend on a lot of things, but if you plan for it in design it's possible. I think if you want three stages or a massive ship, it's going to be a lot trickier. Start small and work your way up.

Good Luck!

[MedwedianPresident]

Thanks. I will try this out. I also found an image of a similar idea:

[MarvinKitFox]

... I chose to set the rocket/payload on a suborbital trajectory, then let it fly out of physics range while recovering the first stage. Then you can switch back to the rocket portion and establish orbit.

Doesn't this inevitably lead to "cheating" , by eliminating air drag from the ascending stage because you are not subjecting it to fizzics?

I should know, I have a comms sattlite in a stabile 30x35km polar orbit around Kerbin. works fine, I must just never visit it, or it vanishes in a red-hot puff of logic.

[Claw]

Doesn't this inevitably lead to "cheating" , by eliminating air drag from the ascending stage because you are not subjecting it to fizzics?

I should know, I have a comms sattlite in a stabile 30x35km polar orbit around Kerbin. works fine, I must just never visit it, or it vanishes in a red-hot puff of logic.

Sure, but I suppose at some level you have to trust yourself to actually fly something "reasonable". My Scorpion design releases around 35 km, and the orbital plane has plenty of juice to obtain a PE > 90km before leaving physics range. So I suppose you'd have to believe that it would at least establish itself above 70km even with aerodynamic drag. I didn't mean to imply that I simply establish it at 40km and call it a day. Just enough to be a "reasonable" suborbital to allow time to recover the carrier, then switch back and establish orbit.

The other way you could swing this (as I have seen done in challenges) is to fly your profile and prove that you can recover the first stage. Then subsequent flight(s) involve launching the second stage and letting the first stage get deleted during it's descent with the roleplay/understanding that it "returned." (Obviously complicated if you have kerbals on board.)

What you say is probably even more of a "problem" for a three stage design. I think that because a three stage design starts with the assumption that the first stage isn't going to get very high. If it does manage to get higher, it will probably be difficult to switch back and forth between three craft fast enough to prevent deletion or "cheating drag" on rails.

Also, my guess is that if you can get high enough on your first stage to prevent deletion, such as my Scorpion, then you probably don't really need three stages.

[Claw]

This sounds very similar to Virgin Galactic...

Actually, using their method would probably better;

By the way, I have designed carriers that hang the orbital platform as well. They tended to have higher part counts and were usually a lot more bendy than my piggyback carrier. Although it was easier to control CoM/CoT/CoL relationships in the design.

[Wahgineer]

With 0.24 on the way, it may be possible that an 'auto recovery' mechanic may be added for those stages that are considered by the game to have enough wings/parachutes to land safely. This means that the hypersonic lift stage would be de-spawned, but the game would say "xxxxxx spacecraft returned safely to runway". This way, money wouldn't be lost for those who pseudo ditch their recoverable stages.

[MarvinKitFox]

With 0.24 on the way, it may be possible that an 'auto recovery' mechanic may be added for those stages that are considered by the game to have enough wings/parachutes to land safely. This means that the hypersonic lift stage would be de-spawned, but the game would say "xxxxxx spacecraft returned safely to runway". This way, money wouldn't be lost for those who pseudo ditch their recoverable stages.

Ooh rilly!? It would be awesome if they crank up the economic model far enough that such a thing would actually matter!

..., my guess is that if you can get high enough on your first stage to prevent deletion, such as my Scorpion, then you probably don't really need three stages.

Very true.

For example, Virgin Galactic's first staging event occurs at respectable altitude, but trivial velocity. (15000m, and a mere 80m/s)

In KSP, that would result in instantaneous deletion as soon as the ships separate past fizzicks range.