Radian SSTO Spaceplane

[edwest4]

Why not use the original Saenger Antipodal Bomber launch method? A 1.4 kilometer monorail with a 5 degree elevation toward the end. Place spaceplane on it, with two V-2 rocket engines right behind it. They provide the initial boost and you can then land the spaceplane where you'd like.

 

[Grey Havoc]

https://twitter.com/x/status/1815427084363202849

View: https://twitter.com/RadianSpace/status/1815427084363202849/photo/1

 

[robunos]

Why not use the original Saenger Antipodal Bomber launch method? A 1.4 kilometer monorail with a 5 degree elevation toward the end. Place spaceplane on it, with two V-2 rocket engines right behind it. They provide the initial boost and you can then land the spaceplane where you'd like.

View: https://www.youtube.com/watch?v=Mvm5NEUwd8k


cheers,
Robin.

 

[Byeman]

Something like that —-SuperHeavy would give a far better boost than a sled. Booster VTOVL, spaceplane lands horizontally.

Same nonsense infects every thread

 

[TAOG]

Radian Aerospace Deep Dive

Radian Aerospace has set out to build the world’s first single-stage-to-orbit (SSTO) spaceplane, the Radian One. The company is designing the fully reusable spacecraft to be not just a spaceplane but also a multifunctional platform, capable of performing a broad array of missions in space, many...

payloadspace.com

Radian Aerospace begins tests of spaceplane prototype

Radian Aerospace, a company with ambitions to develop a reusable orbital spaceplane, has started flight tests of a prototype vehicle.

spacenews.com

 

[Archibald]

Ok so
-they plan to use methalox. SpaceX claims they can get a specific impulse of 375 seconds, which is pretty high for a non-LH2 propellant combo.
-And then there is the sled up to Mach 0.7. This should scrap 1000 m/s out of ascent to orbit delta-v.

These two elements make Radian SSTO slightly more realistic.

Dumb math
9.81*375*ln((100)/(10))+1000 = 9470 m/s

So
-orbit, maybe
-except with zero payload
-and a propellant mass fraction of 0.90 which will be no picnic for a winged SSTO.
-Boeing built a section of RASV hydrolox tankage, propellant mass fraction 0.88 in 1983 for DARPA HAVE REGION

Dense propellants like methalox can drop ascent to orbit delta-v to 9124 m/s (from the attached document)



I get 1 ton of payload to
9.81*375*ln((100+1)/(10+1))+1000 = 9156 m/s

Conclusion: as usual with SSTOs, payload and even orbit are on the ragged edge, it takes very little to wipe out both.

 

[Archibald]

With the above caveats, I still think Radian is worth trying. A daring and bold atempt at SSTO, using SpaceX breakthroughs in methalox rocket propulsion.
When non-hydrolox, every single second of specific impulse makes a difference. Before SpaceX the highest non-hydrolox isp was the Russian kerolox RD-0124 at 360 seconds. Raptor pushes that to 375 seconds, a non negligible gain particularly for SSTOs.

 

[Archibald]

I browsed an old concept called Maglifter, studied by NASA 30 years ago. The maglev sled would have accelerated to 600 MPH, approximately Mach 0.8: seems Radian will use the same trick.

The present speed record for Maglev train : 375 mph. Wonder how it weights...

L0 Series - Wikipedia

en.wikipedia.org

"L0 series""25 tons" - Google Search

At completion, 14-car L0 series MAGLEV trains are estimated to weigh 420 ton and carry 1000 passengers

That's it: 420 tons at Mach 0.6

Wayback Machine

A study by Klijn et al. concluded that at an altitude of 15,250 m, a rocket launch with the carrier
vehicle having a zero launch velocity at an angle of attack of 0° to the horizontal experienced a
Δv benefit of approximately 600m/s while a launch at a velocity of 340m/s at the same altitude
and angle of attack resulted in a Δv benefit of approximately 900m/s. The zero launch velocity
situations can be used to represent the launch from a balloon as it has no horizontal velocity.
Furthermore, by increasing the angle of attack of the carrier vehicle to 30° and launching at
340m/s, they obtained a Δv gain of approximately 1,100m/s.

From the above, I would say that Radian sled should scrap 1000 m/s out of ascent to orbit.

Also Raptor 3 seems to target a specific impulse of 380 seconds, methalox of course.

9.81*380*ln((200+2)/(20+2))+1000 = 9265 m/s with 2 tons payload, a PMF of 0.90 and a MTOW of 200 tons.