Project DeltaGlider-R ('R' for 'realistic')

[N_Molson]

Here we go again. Had this in my mind for a couple of years. More than a couple actually, maybe more like a decade :lol: Feel free to give your opinion, that's the whole point of this thread !

Role : crew shuttle, intended to ferry 'nauts to orbital stations or orbiting "space-only" interplanetary vessels (typically using nuclear reactors). Of course, crew can be replaced by some cargo if the need arises.

Crew : 2 to 5

Systems : mostly 80's technology, nothing crazy.
- Power : batteries. A solar array can be installed in the payload bay for missions that require extended duration.
- Radiators : panels fitting the payload bay doors.

Propulsion :
- Main : 1x AJ-10-190 (aka OME). Thrust : 26.7kN. Isp : 316 sec. Fuel : MMH. Oxidizer : N2O4. Gimbal range : 6° pitch, 7° yaw.
- RCS : R-40A bipropellant thrusters.
- Delta-V (projection) : around 1000 m/s.

Mass : to be determined. Probably around 30 tons ?

Docking :
- Dorsal APAS-95 compatible docking mechanism.

Payload :
- Remote Manipulator System (aka robotic arm).

Booster :
Probably 1x RS-68 engine (Delta IV) + 2x Hercules SRMU (Titan IV-B).


Note : stock DG 'nauts' used only as a reference and scale.

 

[Mojave]

oo, I really like this idea.

 

[Kyle]

This looks seriously cool -- looking forward to seeing the final product.

 

[N_Molson]

I made some propellant mass calculations and it turns out that those propellant tanks might be way oversized. So maybe I'll be able to fit a small payload bay, which would be a nice addition.

 

[Trekkie]

This looks promissing!

 

[Xyon]

Very nice!

 

[Interceptor]

Great thinking.:thumbup:

 

[Linguofreak]

Systems : mostly 80's technology, nothing crazy. Power via 2xFCs or battery arrays (tbd). Typical duration of a transfer should not exceed 48 hours, and batteries would allow to stay docked at the station for weeks (you can't turn off a FC. Or you don't restart it - watch Apollo XIII -). So probably batteries.

The inability to restart the fuel cells had nothing to do with fuel cells not being able to restart after being turned off, it had to do with the fact that two FCs had their oxygen valves James shut by the explosion, and the remaining oxygen tank had a fuel line or valve that leaked its contents into space due to damage, so there was no oxidizer to run the remaining fuel cell with.

 

[Urwumpe]

The inability to restart the fuel cells had nothing to do with fuel cells not being able to restart after being turned off, it had to do with the fact that two FCs had their oxygen valves James shut by the explosion, and the remaining oxygen tank had a fuel line or valve that leaked its contents into space due to damage, so there was no oxidizer to run the remaining fuel cell with.

Oh, there was another reason. Starting a fuel cell is only possible be GSE (at Apollo, the Space Shuttle can restart them), because the electrolyte inside the fuel cell has to be heated to become liquid. Once the fuel cell cools down below 220°F, its solid & dead. The only way to heat the electrolyte is by GSE.

 

[MaverickSawyer]

Upsides to the fuel cells: Water production as a byproduct, and they can produce power on demand.
Downside: Need for reactant storage, which with hydrogen, could be tricky, as you either have to have high pressure bottles or stupidly good insulation. Also, they are NOT reversible, as that requires an electrolysis unit.

Upside to batteries: Modern battery chemistries can pack a staggering amount of energy into them, and, as mentioned, are rechargeable from the host ship, allowing extended stays on orbit for things like fitting-out missions for a high-endurance vessel bound for Mars.
Downside: High energy density batteries can be volatile if damaged, to put it lightly, and with lithium-ion batteries, once they start to go... that's it. There's no way to fight that fire, as from my understanding, it's self-sustaining.

Personally... I think I'd go for batteries and a small retractable solar array, tucked around the dorsal surfaces, perhaps over the radiators. Doors open up, solar panels tip out to meet the sun, possibly shading the radiators in the process?

 

[Ripley]

Cool!
MOAR DGs!

 

[Linguofreak]

Upsides to the fuel cells: Water production as a byproduct, and they can produce power on demand.
Downside: Need for reactant storage, which with hydrogen, could be tricky, as you either have to have high pressure bottles or stupidly good insulation. Also, they are NOT reversible, as that requires an electrolysis unit.

Not to mention hydrogen embrittlement.

OTOH, in space you have the biggest vacuum flask in the universe, and evaporative cooling works well if you have the mass budget to carry a bit extra.

 

[N_Molson]

Well again a typical flight should not last much more than 48 hours. Station rendez-vous & docking can be done in less than 6 hours.

So yeah batteries.

I halved the tanks capacity (still generous amount of propellant, wet mass probably more like 40 tons). So we should have a quite maneuverable LEO shuttle, which was the point. So now we have a payload bay, which defintively opens possiblities, like deploying a small satellite.

Here you can see a setup for longer missions. I'd highly recommend keeping the crew to 3 for such missions, the cabin volume isn't that large at all ! Plus it would require less consumables.



---------- Post added at 08:04 PM ---------- Previous post was at 10:40 AM ----------

Just curious, should I triangulate faces on Blender before exporting to msh ? I feel like Orbiter will be happier with triangles rather than quads, but have no hard fact to support that theory.

I'm quite happy with the hull shape - not too hard, that's more or less a DG

Now to the serious stuff that will make the model look good (or not) : hatches, windows, landing gear, control surfaces, RCS... I'll keep getting my inspiration from the Space Shuttle, so RCS blended into the hull (no holes in parts exposed to the plasma flow) and minimal windows (no need to overexpose the crew to space radiations ^^).

 

[Urwumpe]

I feel like Orbiter will be happier with triangles rather than quads, but have no hard fact to support that theory.

You feel right - Orbiter only supports triangles.

 

[N_Molson]

Found the Holy Grail : OME drawing with dimensions :thumbup:

The whole Aerojet/Redmond catalogue isn't bad either :

https://www.alternatewars.com/BBOW/Space_Engines/2011-H-4232DataSheets.pdf

---------- Post added at 10:40 PM ---------- Previous post was at 09:10 PM ----------

And here we go (in true dimensions), it fits perfectly :





---------- Post added 08-12-19 at 06:43 PM ---------- Previous post was 08-11-19 at 10:40 PM ----------

Visibility won't be fantastic, that's the drawback of the slanted windshield. But hey, as long you can have a visual the runway... Also a porthole for docking operations.

Been working on RCS too. Those thrusters are modeled (real dimensions) after the R-40B, which is very close to the R40A used on the Orbiter. Nozzle diameter of those is 40mm. Of course, I plan to blend them into the hull.

 

[Fabri91]

Kind of looks like what the STS orbiter was supposed to be before the Air Force came along with their payload and crossrange requests accompanied by fat stacks of cash.

 

[DaveS]

Kind of looks like what the STS orbiter was supposed to be before the Air Force came along with their payload and crossrange requests accompanied by fat stacks of cash.

Actually, NASA paid for everything: R&D, manufacturing, GSE, you name it. The DOD only provided early political support. Discovery which was supposed to be the "Blue orbiter" stationed at VAFB was entirely paid for by NASA, so the USAF got a 2 billion dollar orbiter entirely free of charge. The only thing the USAF paid for was the launch complex at VAFB and the Filament Wound Case SRBs. And as far as the cross-range is concerned, NASA needed it as well for certain abort modes. And they did agree with the USAF on the PLB size as it was dictated by the size of future space station modules.

 

[Urwumpe]

Still, the wings and the crossrange got a lot larger because of THE single special Airforce mission profile.

 

[N_Molson]

Blender is really powerful, provided you spend some time watching tutorials. Bevel makes such good-looking porthole corners.

So now we have nice holes in the hull. Can prove useful to see things outside. And that technique (boolean difference) is also going to work nicely to blend RCS thrusters into the hull.

 

[N_Molson]

The ground hatch/door, and progress on the payload bay. Wings should look a little better too.

Finding the best location for the RCS thrusters is not going to be easy, given a) its never easy to find a fictional spacecraft Center of Mass b) that the CoM shifts as propellant is burnt and the payload is released. Have to add a set of "fine control" RCS thrusters too.

Also, given the relative small size of the spacecraft, the nosewheel housing will probably make some kind of bump on the cabin floor.