[Spaceships] Is This Legal?

[MatthewVilter]

Originally Posted by Flyndaran

Okay, I failed my reading comprehension roll.
An A.I. piloted booster rocket ship attached via an external clamp onto the manned ship works, right?

Yep.

Originally Posted by Flyndaran

I'm under the weather today, and am not comprehending things I otherwise would.

No worries! Any choice for what "on top" means for a vehicle type that takes off vertically, hangs out in freefall, and then lands horizontally is arbitrary anyway.



Okay so...I had to do some analysis...working notes follow...

Going for LEO at TL 8...

Booster Drone
TL 8 SM+(n) Winged Hull with Total Automation
Lifts a SM+(n-2) craft onto a suborbital trajectory. The payload will need a Chemical Rocket and it’s own fuel to make orbit.

Front:
1 x Metallic Laminate Armor
1 x Control Room
4 x Fuel Tank

Central:
1 x External Clamp //by RAW it is better to just use a Small Upper Stage and yeah, if the mount configuration was going to mass this much I think people would get pretty clever about building stable, vertically stacked, independently aerodynamic configurations - IRL either configuration would add some amount of mass and technical complexity
2 x Payload //just leaving this space unused makes the whole design process much easier, not really different from cargo I guess
4 x Fuel Tank

Rear:
1 x Jet Engine (1G, 1 hour/tank)
1 x Chemical Rocket (3G, 0.15 mps/tank)
1 x Jet Fuel Tank
4 x Fuel Tank


Next I run the numbers on the performance of some alternative engine and fuel configurations. I have not really looked at craft or fuel costs yet.

With 1 Rocket Engine:
14 RP-1/LOX (3.36 mps delta-V) = 3.36 => the payload will need 2.24 more delta-V (11 tanks) //for reference

With 1 Rocket Engine and 1 Tank of Jet Fuel:
12 RP-1/LOX, 1 Jet Engine (0.694 mps airspeed + 2.52 mps delta-V) = 3.21 => the payload will need 2.39 more delta-V (12 tanks) //this is the configuration in the listing above
11 RP-1/LOX, 2 Jet Engines (0.972 mps airspeed + 2.31 mps delta-V) = 3.28 => the payload will need 2.32 more delta-V (12 tanks)
10 RP-1/LOX, 3 Jet Engines (1.19 mps airspeed + 2.1 mps delta-V) = 3.29 => the payload will need 2.31 more delta-V (11 tanks)
9 RP-1/LOX, 4 Jet Engines (1.39 mps airspeed + 1.89 mps delta-V) = 3.28 => the payload will need 2.32 more delta-V (12 tanks) //you might run out of jet fuel before you clear atmo with these multi-jet-engine configs - they are fuel hungry and get marginal airspeed buffs...need to run the numbers...
8 RP-1/LOX, 5 Jet Engines (1.56 mps airspeed + 1.44 mps delta-V) = 3.0 => the payload will need 2.6 more delta-V (13 tanks) //this is the break point for fuel tank number

If you give the payload a Nuclear Thermal Hydrogen Rocket instead it can make orbit with just 6 tanks of LH2

If you use Nuclear Thermal Hydrogen Rockets for blastoff you can do SSTO and just forget the whole premise of this thread. ;)

With 2 Nuclear Thermal Hydrogen Rockets //runway takeoff
13 LH2 (9.36 mps delta-V) = 9.36

With 6 Nuclear Thermal Hydrogen Rockets //VTO at 1.2G
9 LH2 (5.67 mps delta-V) = 5.67

And if you are really serious about cheap fuel...

With 2 Nuclear Thermal Water Rockets:
13 H2O (3.12 mps delta-V) = 3.12 => the payload will need 2.48 more delta-V (12 water tanks)

Even if you read the NTR entry (p. 22) as a misprint where “...or 0.45 mps (TL8).” should read “...or 0.45 mps (TL9).” you can still do SSTO...

With 2 (definitely TL 8) Nuclear Thermal Hydrogen Rockets //runway takeoff
13 LH2 (6.24 mps delta-V) = 6.24


What we are working with:
TL 8:
Jet Engine (1G, 1 hour/tank)
Chemical Rocket (3G, 0.15 mps/tank)
Ion Drive (0.0005G, 3 mps/tank)
Nuclear Thermal Hydrogen Rocket (0.2G, 0.3-0.45 mps/tank)
Nuclear Thermal Water Rocket (0.6G, 0.1-0.15 mps/tank)
External Pulsed Plasma (2G, 3 mps/tank)

I am don’t think an Ion Drive is strong enough to take suborbital to orbital before falling back to earth. I am not even going to get into the Orion Drive... >_<