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Is it feasible for them to build an orbital version? I want the concept of launching from altitude to work because it seems like the heavy atmosphere part has

by ilaksh 3y ago

Is it feasible for them to build an orbital version? I want the concept of launching from altitude to work because it seems like the heavy atmosphere part has different requirements and so having another vehicle to help with that seems intuitive. I also wonder if you could make orbital flight with this type of system more achievable if the delivery aircraft and/or the rocket had scramjet ability so that it was more efficient.

Analemma_ 3y ago
No, it can't even come close to reaching orbital velocity. Fundamentally it's just a plane with a rocket motor on it that can go up and back down; something which could orbit and deorbit would be a completely different vehicle entirely.
rqtwteye 3y ago
Not an expert but as far as I know, orbital is way, way more difficult. You need to reach speeds several times higher and then also deal with reentry
brucethemoose2 3y ago
> I want the concept of launching from altitude to work because it seems like the heavy atmosphere part has different requirements and so having another vehicle to help with that seems intuitive. This is essentially what multi-stage rockets are. Only the lowest stage is optimized for heavy atmosphere. The "dropping from a plane" thing is theoretically a good idea. Wings and jets save lots of fuel. But in practice one needs a hilariously large plane to carry a modest rocket, and it needs to be hypersonic to really give the dropped rocket a good orbital kick, and the linkage between the rocket/plane needs to not blow up. Historically... You mind as well build a massive vertical first stage. You could strap jets to a first stage and try to reuse it. Hello KSP!
ramesh31 3y ago
>I want the concept of launching from altitude to work because it seems like the heavy atmosphere part has different requirements and so having another vehicle to help with that seems intuitive. This is what they tried and failed with Virgin Orbit. The economics of plane launch just don't work out versus the logistical hassle of it.
tantalor 3y ago
https://en.wikipedia.org/wiki/Sub-orbital_spaceflight https://en.wikipedia.org/wiki/Sub-orbital_spaceflight
throwaway4220 3y ago
You may be interested in skulon https://en.m.wikipedia.org/wiki/Skylon_(spacecraft) https://en.m.wikipedia.org/wiki/Skylon_(spacecraft)
- ilaksh 3y ago
  I hope it is fully realized in the future. Seems amazing.
- moralestapia 3y ago
  From the Wikipedia page: "It could carry X tonnes of cargo [...] over 24% more than SpaceX Falcon 9 launch vehicle in reusable mode" Lol, one small difference tho, one exists in the real world, the other one in the minds of a few British peeps.
  - Already__Taken 3y ago
    they did prove the precooler work though
cobaltoxide 3y ago
Nope. As a point of comparison, the orbital velocity of ISS is 17,000 mph. The max speed of Unity was given as Mach 2.88. The speed of sound varies from 340 m/s at sea level to 200 m/s at 120,000 feet. So Mach 2.88 would correspond to somewhere between 1000 - 2000 mph depending on where it was attained. To enter orbit, a vehicle must be simultaneously at orbital altitude _and_ at orbital velocity (in the correct direction). Furthermore, note that quoting speed as a Mach number is fundamentally only relevant to atmospheric flight. Mach number is referenced to the speed of sound, and sound does not travel in the vacuum of space. The Virgin Galactic vehicle shoots up to very high altitude but then simply falls back to earth.
Iwan-Zotow 3y ago
No. It is slower than MiG-31

by ilaksh 3y ago

Analemma_ 3y ago

No, it can't even come close to reaching orbital velocity. Fundamentally it's just a plane with a rocket motor on it that can go up and back down; something which could orbit and deorbit would be a completely different vehicle entirely.

rqtwteye 3y ago

Not an expert but as far as I know, orbital is way, way more difficult. You need to reach speeds several times higher and then also deal with reentry

brucethemoose2 3y ago

> I want the concept of launching from altitude to work because it seems like the heavy atmosphere part has different requirements and so having another vehicle to help with that seems intuitive. This is essentially what multi-stage rockets are. Only the lowest stage is optimized for heavy atmosphere. The "dropping from a plane" thing is theoretically a good idea. Wings and jets save lots of fuel. But in practice one needs a hilariously large plane to carry a modest rocket, and it needs to be hypersonic to really give the dropped rocket a good orbital kick, and the linkage between the rocket/plane needs to not blow up. Historically... You mind as well build a massive vertical first stage. You could strap jets to a first stage and try to reuse it. Hello KSP!

ramesh31 3y ago

>I want the concept of launching from altitude to work because it seems like the heavy atmosphere part has different requirements and so having another vehicle to help with that seems intuitive. This is what they tried and failed with Virgin Orbit. The economics of plane launch just don't work out versus the logistical hassle of it.

tantalor 3y ago

https://en.wikipedia.org/wiki/Sub-orbital_spaceflight https://en.wikipedia.org/wiki/Sub-orbital_spaceflight

throwaway4220 3y ago

You may be interested in skulon https://en.m.wikipedia.org/wiki/Skylon_(spacecraft) https://en.m.wikipedia.org/wiki/Skylon_(spacecraft)

ilaksh 3y ago
I hope it is fully realized in the future. Seems amazing.
moralestapia 3y ago
From the Wikipedia page: "It could carry X tonnes of cargo [...] over 24% more than SpaceX Falcon 9 launch vehicle in reusable mode" Lol, one small difference tho, one exists in the real world, the other one in the minds of a few British peeps.
- Already__Taken 3y ago
  they did prove the precooler work though

cobaltoxide 3y ago

Nope. As a point of comparison, the orbital velocity of ISS is 17,000 mph. The max speed of Unity was given as Mach 2.88. The speed of sound varies from 340 m/s at sea level to 200 m/s at 120,000 feet. So Mach 2.88 would correspond to somewhere between 1000 - 2000 mph depending on where it was attained. To enter orbit, a vehicle must be simultaneously at orbital altitude _and_ at orbital velocity (in the correct direction). Furthermore, note that quoting speed as a Mach number is fundamentally only relevant to atmospheric flight. Mach number is referenced to the speed of sound, and sound does not travel in the vacuum of space. The Virgin Galactic vehicle shoots up to very high altitude but then simply falls back to earth.

Iwan-Zotow 3y ago

No. It is slower than MiG-31