Request SSTO VTOVL

[mc_]

IMHO it would be nice to see a reusable SSTO VTOVL (single-stage-to-orbit Vertical Take-Off Vertical Landing) vessel in Orbiter. It's sad we still dont have anything like it (evryone is about DGIV/XR2-style ships for some reason).

There are some examples of the design.

UMMU and UCGO support also would be great, but it looks like will approve it anyway.

Maybe i could start building a VTOVL myself, but i'm busy with another addon now.

P.S.: sorry for lame english

 

[cjp]

Yes, I'd like to see one too. It should be a semi-realistic design: something that should be possible with realistic estimates of material properties and aerodynamic and engine performance, and maybe slightly optimistic estimates of the amount of actual design issues.

I'd like to see something like the majority of designs on the website you link to: something that already looks a bit like a re-entry capsule when it's still on the launch pad. No wings, just a cone-like shape with a heat shield and engines on the bottom.

Should we go for one of the existing designs, or make one ourself? The Delta Clipper is probably the most well-known example, but I've read that its stretched shape is optimized for giving it more cross-range maneuvering during re-entry, which is nice for military applications, but sub-optimal for what I'm interested in: transport of astronauts to/from LEO. And, after re-fueling, to/from the lunar surface!!

The design should be optimized for a maximum payload for a minimum of operational costs.

I think it's only interesting as an astronaut transporter. For cargo, there are less strict safety requirements, and cargo can be made to withstand extremer G-forces, vibrations, temperatures etc.., and it generally doesn't need to be brought back to earth.

 

[mc_]

I agree with everything you said. Landing to Moon (or Mars) supposed to be one of the primary objectives for this vessel (and that is why VTOVL is better than VTOHL).

But "heat sheld on the bottom"... We can have something better, but still "no wings" :thumbup:.
Think about combining the Delta Clipper with russian Kliper concept (see 2004 lifting body version).

 

[cjp]

But "heat sheld on the bottom"... We can have something better, but still "no wings" :thumbup:.
Think about combining the Delta Clipper with russian Kliper concept (see 2004 lifting body version).

What is the advantage of that?

Besides, if the thing is supposed to return from the moon, should it be capable of doing an 11 km/s re-entry? In that case, I think there is no escape from using an ablative heat shield.

If only slower re-entry modes need to be supported, I think a radiative heat shield sounds promising. It can be made of a metallic material (some nickel alloy), so it's probably less vulnerable than the capacitive heat shield of the Space Shuttle, and it doesn't need to be replaced or repaired after every flight.

 

[CigDriver]

This is something I've wanted to build for a while now. I really like the Pacific American Launch Systems Phoenix designs.

I played around a bit with designs with the minilander I built for the HyperDart. But, I never got it to fly like I wanted. It was supposed to reenter as a lifting body then pitch up for a vertical landing. The problem was the lifting body stalled and you couldn't pitch up The phoenix design looks like that could be avoided since it uses an ablative heatshield and would fly its entire reentry tail first.

Something to think about

 

[mc_]

Yeah, it sounds crazy, but it's possible

On that page i saw a picture illustrating something like "Kliper lunar orbit mission profile", but there was a 2005 winged version on it. And it's clear that "lifting body" requires less accuracy and stability then winged version. So, if winged Kliper is supposed to do 11 km/s re-entry, lifting body Kliper shoul do it easier (not for crew, heh).

But a "pitching up" problem looks like a weak spot - Kliper (2004 lifting body version) was supposed to perform a parachute landing in horizontal position:

Otherwise, if we need something more reliable, "heat sheld on the bottom" is better - vessel is supposed to have the only tstable position duaring re-entry - heat sheld down.
So, its a simpe-stupid model, which shoul always work well.

And... don't know how to say it...

...something that already looks a bit like a re-entry capsule when it's still on the launch pad. No wings, just a cone-like shape with a heat shield and engines on the bottom...

It's a classic, a true old-school vessel without bells and whistles.
And we still don't have one for Orbiter.

Now let's wait for someone else to wisit this thread, to see if a VTOVL ship is really needed for someone.

 

[cjp]

This is something I've wanted to build for a while now. I really like the Pacific American Launch Systems Phoenix designs.

Yes. I only don't understand why its crew compartment is between the different fuel tanks. The conventional place, near the nose cone, seems better.

The way I see it (top to bottom):

• docking port
• crew compartment
• fuel tanks
• aerospike engine + ablative heat shield
• retractable landing gear (no wheels)

Additionally, there are several RCS units near the nose and near the bottom.

Re-entry should happen as follows:

• Bottom-first atmospheric entry (up to earth escape velocity, to support lunar / interplanetary returns)
• Typical ablative re-entry profile (IIRC that's a fast deceleration high in the atmosphere)
• Bottom-first free-fall towards the ground
• Gear down
• Rocket-powered slow-down, followed by landing on land.

The heat shield should be designed in such a way that it's cheap and easily replaceable, because it has to be replaced each time. Maybe RCS engines and other sensitive parts should be protected somehow from deposition of heat shield material. But it's probably better to not simulate these things in Orbiter.

What about the launch location? If the main landing mode is land-based, then a launch over land is preferred. Another advantage is that on land there are lots of airports where there's rescue personnel, so there's no need for a costly S&R fleet. The risk of crashing on an uncontrolled location should be minimized, so that people who live there don't complain about the launches.

 

[CigDriver]

Yes. I only don't understand why its crew compartment is between the different fuel tanks. The conventional place, near the nose cone, seems better.

The way I see it (top to bottom):

• docking port
• crew compartment
• fuel tanks
• aerospike engine + ablative heat shield
• retractable landing gear (no wheels)

Two theories on the fuel tank placement. First would be balance. Second, would be crew comfort for rotation movement. If you are doing a pitch move to align with something you would get a lot of vertical movement if you are at the nose, closer to CG it is more just a rotation. Of course this doesn't seem to be an issue for the shuttle.

 

[cjp]

Two theories on the fuel tank placement. First would be balance. Second, would be crew comfort for rotation movement. If you are doing a pitch move to align with something you would get a lot of vertical movement if you are at the nose, closer to CG it is more just a rotation. Of course this doesn't seem to be an issue for the shuttle.

No, it doesn't seem to be an issue for the space shuttle.

Look at this picture:

The long pipe to the docking port is clearly a disadvantage.

About the balance: the only issue I can think of is the position of the center of gravity during re-entry. It should be such that the tail-first orientation is aerodynamically stable, when the fuel tanks are nearly empty. I guess a lower CG is better, but I'm not really sure.

Sitting in-between huge rocket fuel tanks sounds even worse than sitting on top of a rocket fuel tank.

Besides, I think most of the Phoenix designs are too large. What I'd like to see in Orbiter has a crew size of about 3 or 4 people (two pilots and one or two passengers).

 

[mc_]

Sitting in-between huge rocket fuel tanks sounds even worse than sitting on top of a rocket fuel tank.

But i think it is a right place.

After landing to the Moon (for example) crew will need to go out of the ship (and, probably, unload some cargo) With crew cabin and cargo bay in the center it would be easier (ladder will be shorter :lol.

So, i vote for the center position.

Besides, I think most of the Phoenix designs are too large. What I'd like to see in Orbiter has a crew size of about 3 or 4 people (two pilots and one or two passengers).

What about something like Phoenix L?
Anyway, it is possible to create some kind of a "new Phoenix", whitch is corresponding to the requirements:

• docking port
• crew compartment
• fuel tanks
• aerospike engine + ablative heat shield
• retractable landing gear (no wheels)

 

[cjp]

But i think it is a right place.

After landing to the Moon (for example) crew will need to go out of the ship (and, probably, unload some cargo) With crew cabin and cargo bay in the center it would be easier (ladder will be shorter :lol.

So, i vote for the center position.

Ok, I won't resist anymore, let's go for center position, because it requires less equipment on departure/arrival sites. How about combining it with a docking port on the side instead of in the nose?

This reminds me of a very old design of me (more than 10 years old), where the entire heat shield would split up into 4 sections, to form the landing legs. There would be a crew/cargo unit in the bottom of the spacecraft, just above the heat shield.

Anyway, it is possible to create some kind of a "new Phoenix", which is corresponding to the requirements:

I am thinking in that direction.

 

[sputnik]

Actually, there is one: [nomedia="http://www.orbithangar.com/searchid.php?ID=1882"]SASSTO v1.0[/nomedia]

I like the idea too, but what the SASSTO has persuaded me is that more VTOVL SSTO's should wait until Orbiter has some better tools for the purpose. Like good re-entry guidance or autopilot.

 

[CigDriver]

The big advantage to the nose docking port is ease of docking since all the controls are the same. Of course it could be coded like the XR5 (I think it is the XR5) where you can switch between normal and docking RCS. The other hard thing about the side mounted docking port is getting it close to the center of rotation. Docking would be a nightmare if you rotated and messed up your alignment. Of course we can fudge things a bit since it doesn't really have to work

Splitting the heatshield for landing is interesting. The big drawback I see is moving those large pieces around in the airflow after you get going or are headed in for landing. I like how the Phoenix designs have little doors for each thruster, seems like less aerodynamic headaches to me.

 

[cjp]

Actually, there is one: SASSTO v1.0

I like the idea too, but what the SASSTO has persuaded me is that more VTOVL SSTO's should wait until Orbiter has some better tools for the purpose. Like good re-entry guidance or autopilot.

Thanks. I'll try it later. Only this part in the Readme worries me: "You MUST have Gemini-Titan v4.11 or later for this add-on to work!"

The big advantage to the nose docking port is ease of docking since all the controls are the same.

Come on, the Space Shuttle has the same issue. Did you never manage to dock the Space Shuttle to anything? This sort of challenges make the flying interesting!

One trick is to do the orientation first, and then the positioning. The other trick is to get used to strange linear RCS orientations.

Splitting the heatshield for landing is interesting. The big drawback I see is moving those large pieces around in the airflow after you get going or are headed in for landing.

I don't think anymore that it is a good idea. As I said, it is a design from me at least 10 years ago. All the extra structure and hydraulics would add huge amounts of weight to the vehicle. I now think that a smaller landing gear is better.

But still, why would a mid-vehicle crew compartment be better than a crew compartment in the bottom?

Next design (from top to bottom):

• Fuel tanks
• crew compartment + sideways docking port
• aerospike engine set integrated in ablative heat shield
• landing gear

When it comes to re-entry and landing aids: for re-entry I use Aerobrake MFD. For landing, I can remember at least one add-on that had a sort of autopilot for that (which probably consumes less fuel than human-operated retro rockets).

 

[T.Neo]

Perhaps my space tugs concepts?

They're not really based off realistic technology or designs, but the Lifter fits the bill for a VTOVL spacecraft.

Btw, don't mind the screenshots. The meshes have come quite a ways since then.

 

[Andy44]

I asked for something similar a while back:

http://orbiter-forum.com/showthread.php?t=15074

I could try to build it myself, using sc3, but I wouldn't be able to implement the landing turbojets, since sc3 only supports one main propulsion system. There are ways to "cheat", such as building a dummy vessel with one engine and using the real vessel as an attached payload which gets detached prior to reentry, but that adds complication.

I might try it, though.

Better would be to build a custom dll, which I don't have the time to learn right now.

sputnik is also right about the lack of good semi-ballistic reentry autopilots or pilot-assist tools. The best we've got is Aerobrake MFD, which is okay but not ideal.

 

[CigDriver]

I threw a mesh together and got it in Orbiter via SC3. I based it on the SC3 ini for dragon/falcon 9. It reenters great, but you can't launch it It just flips and spins as soon as you get any velocity. Obviously due to the aero parameters and wanting to fly tail first. I'm going to play a bit with the wing parameters and to make it more stable going forwards. the values should transfer directly into a custom .dll down the road. also, 600Km x 60Km reentry orbit isn't good for astronauts...I saw over 10g at one point

Like I said i just threw the mesh together, no textures or anything. It follows the Phoenix launcher layout, tank-crew-cargo-tank-engines. Engines and gear retract through the heat shield and are covered by doors. I'll finish up the mesh and build a custom .dll at some point.

 

[mc_]

This is it!

It follows the Phoenix launcher layout, tank-crew-cargo-tank-engines. Engines and gear retract through the heat shield and are covered by doors. I'll finish up the mesh and build a custom .dll at some point.

Yeah, this is it :thumbup: Nice classic design, proper size (it could also be used as a lander for a heavy interplanetary ship).

Btw, engines are "main" or "hover"?

 

[CigDriver]

Yeah, this is it :thumbup: Nice classic design, proper size (it could also be used as a lander for a heavy interplanetary ship).

Btw, engines are "main" or "hover"?

I can do both like I did on the minilander. A switch in the vc changed the control scheme from standard to hover.

 

[mc_]

A switch in the vc changed the control scheme from standard to hover.

Good idea.
There are some external camera issues with "tail landers" in Orbiter, so i think that default mode should be "hover". It also will be more handy with default "hover hold alt" autopilot sometimes.
But "prograde", "retrograde", etc will not work properly with hover engine layout...
So, "switch in the vc" is he only solution.

Wait... you said "in the vc"? There will be a vc? :hail: