How close are we from DG and XR planes technology?

[teslax]

In RL things seem a bit dim in my view after the cancellation of shuttle program. The progress with SpaceX planes is promising but then the planes that they have developed are mostly for sub-orbital flights. Costs for launching equipments and satellites in space are also high, that so far only first world nations can afford to develop something in space.

How close do you think are we from the tech in XR and DG planes. I understand there is something physically impossible such as the huge fuel size DGIV can sometime contains. But perhaps, something close to another more advanced space shuttle? Other alternative that I can see is we might going to stay with unmanned probes for at least one century or more for long range space flight. How about the Mars mission, would it be possible to see manned one in this century or maybe in our lifetime?

I think this also has been asked a lot of times, but are XR and DG planes theoretically feasible to be designed and flown? Say if you are given limitless funds by China or some other millionaires to procure and get whatever you need, can you actually put their design into reality?

 

[Urwumpe]

We are VERY VERY far away.

Primary because they all fly with fairy dust, are so light that they could float in the air, and in case of the classic DG, have a RCS that would be completely useless in the real world.

With enough thrust, the shapes can really fly, that has been proven with a RC model.

But in the real world, you have more problems to solve than just making a brick fly.

 

[garyw]

In RL things seem a bit dim in my view after the cancellation of shuttle program. The progress with SpaceX planes is promising but then the planes that they have developed are mostly for sub-orbital flights. Costs for launching equipments and satellites in space are also high, that so far only first world nations can afford to develop something in space.

SpaceX are not building planes. SNC are building the dreamchaser. SpaceX have built a very successful rocket. They are working on return to launch site technique for lowering launch costs.

How close do you think are we from the tech in XR and DG planes. I understand there is something physically impossible such as the huge fuel size DGIV can sometime contains. But perhaps, something close to another more advanced space shuttle?

Space Shuttle II was on the NASA drawing boards for years. The idea was to build more shuttles and retire the older ones but money was always the obstacle.

Building a DG or XR-2 style vehicle is not an issue, creating the magical single stage to orbit fuel that it needs is an issue. Also, in orbiter you can land an XR, refuel and go again. That's not an option with real space vehicles due to the huge stresses they go through.

Other alternative that I can see is we might going to stay with unmanned probes for at least one century or more for long range space flight. How about the Mars mission, would it be possible to see manned one in this century or maybe in our lifetime?

Who knows? If commercial space flight picks up maybe. I can't see government funding going towards Mars because of the global financial issues.

I think this also has been asked a lot of times, but are XR and DG planes theoretically feasible to be designed and flown? Say if you are given limitless funds by China or some other millionaires to procure and get whatever you need, can you actually put their design into reality?

Of course. With limitless funds anything is possible.

 

[Urwumpe]

The thermodynamics of them is also an issue - can you even imagine, what a high exhaust beam power a DG engine has (2x 4.8 GW - for comparison: A single SSME produces at 10 GW power at 109% emergency power, but is about 20 times larger than the DG engines)? It is essentially a large bomb exploding every second (About two tons of TNT every second for the DG)

Unless the engine would have more than 99.8% effectivity (which is physically doubtful, since most heat engine cycles can't exceed 66% effectivity), the heat leaking into the DG structure would vaporize it (too high power density = power per mass).

And depending on the model you use for the radiation of the exhaust, the exhaust could melt tungsten in a very large hemisphere (about 250 meters radius) around the nozzles.

 

[PhantomCruiser]

I think that a DG or XR type ship is way, way way out there in fantasy land. Don't get me wrong, I love to fly them. But for the purposes of realism, they just won't work out.

In the near-term, maybe the closest relative of that type craft might be the Lynx, from Xcor. They want to do the same thing as Virgin Galactic.

Lynx won't have (last I read) a carrier craft to get it to altitude. It's kind of a neat looking craft, I'd like to see it in Orbiter, but I don't have the skills to mesh it up.

 

[RGClark]

We are VERY VERY far away.

Primary because they all fly with fairy dust, are so light that they could float in the air, and in case of the classic DG, have a RCS that would be completely useless in the real world.

With enough thrust, the shapes can really fly, that has been proven with a RC model.

But in the real world, you have more problems to solve than just making a brick fly.

Where are the specs on the DG listed?

Bob Clark

 

[blixel]

Where are the specs on the DG listed?

Check the doc folder of your Orbiter install for the DeltaGlider.pdf file. Pages 7 and 8 list the technical specifications.

EDIT: Here's a screenshot of the specifications in case you don't have convenient access to the pdf.

( Screenshot taken from [ame="http://orbithangar.com/searchid.php?ID=6329"]HazMatt's DeltaGlider Checklist.[/ame])

 

[Pipcard]

This is why the DG is unrealistic: what rocket engine has an I_sp of 4079 s? Can't be an ion thruster, as those have too little thrust.

 

[Urwumpe]

This is why the DG is unrealistic: what rocket engine has an I_sp of 4079 s? Can't be an ion thruster, as those have too little thrust.

Fusion could achieve this easily. Or fairy dust.

 

[Linguofreak]

This is why the DG is unrealistic: what rocket engine has an I_sp of 4079 s? Can't be an ion thruster, as those have too little thrust.

I think it's generally assumed that the DG is powered by gas-core NTRs.

Gas core NTR's don't tend to pass emissions tests.

 

[BruceJohnJennerLawso]

We are VERY VERY far away.

Primary because they all fly with fairy dust, are so light that they could float in the air, and in case of the classic DG, have a RCS that would be completely useless in the real world.

With enough thrust, the shapes can really fly, that has been proven with a RC model.

But in the real world, you have more problems to solve than just making a brick fly.

Very true, although scramjets kinda maybe, if you look at them right, could work out in the future, somewhat similar to this:

[ame="http://www.orbithangar.com/searchid.php?ID=4219"]http://www.orbithangar.com/searchid.php?ID=4219[/ame]

The big problem appears to be:

A-building a durable scramjet.
B-getting enough thrust out of it. The concept works okay-ish at lower altitudes and speeds, but between 70-90 km and fairly high speeds its very tricky to reliably balance airspeed for lift, hull heating, and fuel. A launch system wont be very useful if it cant guarantee reaching orbit every launch.

But it might happen someday, just not tommorow. Theres a great deal of work left to be done in aerospace engineering.

 

[N_Molson]

Let's face it, those spaceplanes are science-fiction.

Now if you use the DG XR-1 and change the Isp to 310 (in the prefs file game write 3000, because Orbiter uses the Exhaust Velocity, which is, AFAIK, Isp * 9.81) it is more like a minishuttle. You can set the engine power to 5000N each, should be fairly realistic for a craft of that size. Hovers should be disabled (set their thrust to 0), unrealistic. But you'll need a launcher of course. Except, maybe, if you start on the Moon.

SpaceX have built a very successful rocket.

Sorry, don't want to derail the thread and again I don't want to seem SpaceX-allergic but I think it is a bit early to say that. Let them make 100 launches and have a 95% success ratio, then yes, the rocket will be "very successful".

 

[Urwumpe]

Let's face it, those spaceplanes are science-fiction.

Now if you use the DG XR-1 and change the Isp to 310 (in the prefs file game write 3000, because Orbiter uses the Exhaust Velocity, which is, AFAIK, Isp * 9.81) it is more like a minishuttle.

Orbiter uses metric specific impulse - in Ns / kg.
It is similar to the exhaust velocity, but not the same.

 

[BruceJohnJennerLawso]

Sorry, don't want to derail the thread and again I don't want to seem SpaceX-allergic but I think it is a bit early to say that. Let them make 100 launches and have a 95% success ratio, then yes, the rocket will be "very successful".

Perhaps better said as "better told by history"

Arguably the point at which a rocket family's success-fullness can start to be measured will be about 300-500 total launches. Anything below that represents too small a sample size to say for sure IMO.

This would be beneficial to a HTOHL spaceplane launch system though. A launch system that flies as regularly and frequently as possible will work better over time, since flaws can be analyzed & studied with more accuracy, and design margin can be pushed more and more than a system with only a handful of flights.

 

[kerlix]

So would it be possible if it took a more "shuttle-like" mission profile?

Using a launcher to get it up and out; something more like shuttle OMS engines for on-orbit propulsion; properly configured RCS; reentry similar in style to the shuttle

Then again, after all that work, it isn't really anything like the DG/DG-IV/XR-1 except in appearance......

 

[Izack]

Well, the lowest-setting DG-IV and the linked Realistic Settings for XR-2 still make for extremely capable and versatile vessels, so it's not too terrible, eh?

 

[BruceJohnJennerLawso]

Well, the lowest-setting DG-IV and the linked Realistic Settings for XR-2 still make for extremely capable and versatile vessels, so it's not too terrible, eh?

True, but even the lowest DGIV settings arent even close in a lot of areas. The Realistic XR2 configs are really hard to fly with, basically a more complex Space Shuttle with Scramjets.

 

[MattBaker]

How many horizontal takeoff and landing spaceplanes to orbit are there? None.
How many suborbital ones? None without a carrier aircraft.

How many orbital ones are in development? One which's schedule gets pushed back more than Nauka's.

So...at least fiveteen years from a HTHL spaceplane to orbit. While the DG is like a HTHL spaceplane to...everywhere (if you have the skills).

Very, very, very, very far?

 

[C3PO]

Very, very, very, very far?

The DG is in the same league as Santa Claus.

 

[BruceJohnJennerLawso]

The DG is in the same league as Santa Claus.

Indeed, thats why its painted red. Santa needs a backup to all those reindeer.