Could This Spaceship Design Work?

[Bamax]

Normally second staging is preferred for space launch as you can launch more payload that way.

Yet I found out that there can be exception to this with more... scifi theoretical designs. Where SSTO is preferred... because do you really want a radioactice resuable booster returning to tge launch pad? Or do you wish to waste a booster every launch?

I will explain the spaceship design here:

I am designing a scifi vessel for fiction, yet it's propulsion will be based on realistic/theoretical means.

The spaceship is a project orion lying on it's belly at launch.

Dual axis launch nozzles at both ends are capable of VTOL, at least until the vessel ascends high enough that it can flip over and detonate a metallic hydrigen bomb.

As it ascends higher into the atmosphere where tge aur is thin the spaceship switches over to basketball sized pure fusion bombs.

https://en.m.wikipedia.org/wiki/Pure_fusion_weapon

Questions: Is the design practical? Just assume that bombs exist already (even though they do not) The vessel is intended to be a true manned SSTO.

Part of the challenge I presume will be finding room for the VTOL engines on the end that has a pusher plate on the rear. But I do not see why such is impossible.

Crew I presume would do egress from the middle of ship when landed on it's belly, since the ends would have space taken up by rocket VTOL engines.



What do you think? I also presume a pure fusion bomb orion to orbit... will use bombs designed to minimize fallout, which means no uranium or plutonium is is used for the bombs.

Yet to minimize neutron activation the vessel needs to ascend high enough that the blast won't cause neutron activation of the ground. That is why thermobaric bombs would be used initially in the ascent upward.

So... is the design practical or did I overlook anything?



Ironicaly this kind of vessel is better off as an SSTO, simply because if you staged it you risk damaging or destroying a resusable first stage rocket when you flip and light off a bomb. You would also risk neutron activation of the first stage from the pure fusion detonation. Meaning the first stage returns ... radioactive. Which is bad

[Bamax]

Edit: Thermobaric bombs I am told would not work due to how they work.

So instead I would use metallic hydrogen bombs part way of the ascent.

[Keklas Rekobah]

Why would you want to destroy the environment below and behind the ship?

Fusion bombs require fission bombs to ignite the hydrogen. Fission bombs require uranium and/or plutonium to work, and they also produce deadly radioactive fallout that can linger in the environment for centuries.

Not to mention the thermal and EMP burst that can destroy life and electronics for dozens of miles around.

Better to use antigravity lifters to boost the ship into orbit, high-energy plasma rockets (HEPLARs) to take the ship past the 100-diameter jump/warp limit, and then engage the star-drive to reach the destination.

Once there, reverse the drive sequence to make planetfall.

[Bamax]

Why would you want to destroy the environment below and behind the ship?

Fusion bombs require fission bombs to ignite the hydrogen. Fission bombs require uranium and/or plutonium to work, and they also produce deadly radioactive fallout that can linger in the environment for centuries.

Not to mention the thermal and EMP burst that can destroy life and electronics for dozens of miles around.

Better to use antigravity lifters to boost the ship into orbit, high-energy plasma rockets (HEPLARs) to take the ship past the 100-diameter jump/warp limit, and then engage the star-drive to reach the destination.

Once there, reverse the drive sequence to make planetfall.

Do you think pure fusion is like a nuke? It is not.

https://en.m.wikipedia.org/wiki/Pure_fusion_weapon


There is some fallout but considerably less because there is no fission trigger.

Why do it? I just was applying knowledge to the SSTO challenge of what besides nukes could work. If we had such bombs.


The fallout products I read do not linger like fisson fallout I read, so the concept seems viable
Just stick the space on a tall mountain or otherwise remote location and launch from there.

Not sure if pure fusion does EMP or not. I know antimatter does not.


Landing will be no worse than normal rocketry.

[Keklas Rekobah]

Still, a HEPLAR drive would cause thermal problems in the immediate area, producing oxides of nitrogen that would destroy whatever ozone layer the planet may have.

But hey, it is your universe, so do not let me stop you.

[Demarquis]

It would work, but I can think of some improvements. The exterior engines could/should be some kind of air-breathing rocket, because that will get you higher into the atmosphere, where the fusion drive will function more efficiently and do less damage.

For that part of it, there is no need to use "bombs" of any kind. Some sort of pulsed propulsion relying on smaller pellets, like project Daedelus or a direct fusion drive would be more efficient. You would not, however, want to any of these alternatives anywhere near population centers. For that, I would recommend some sort of reusable surface to orbital tug.

[avatar576]

Detonating nuclear weapons behind a ship has actually been considered before as a theoretical means of propulsion for interplanetary travel. I'm not sure it has ever been considered as a means of reaching orbit. I can see two reasons why not:
1.) In simplified terms, rockets provide constant thrust, which provide constant acceleration to reach the delta V required to reach orbit. In your proposal, the rockets will only get it part way there, and as soon as the rockets are shut off, the craft will begin losing velocity until the bombs begin to detonate because of gravity and atmospheric drag. Similarly, the tendency will be for the craft to continually lose momentum in between detonations. Thus, some energy will be wasted/lost as the craft "bounces" its way into orbit.
2.) Efficiency. A rocket has the advantage of being able to direct its thrust so that almost all of the energy produced by the reaction is directed through the nozzle to produce thrust. When you detonate a bomb behind the craft, a only relatively little amount of the energy released by the bomb will be transferred to the craft. The rest just dissipates into the atmosphere. Thus, the energy cost of reaching orbit would be significantly greater than a traditional rocket.
The final consideration would be the question of how to deal with "max q". Simply put, this is the point during launch where the launch vehicle experiences the greatest aerodynamic load and mechanical stress due to drag and friction. This is a function of velocity and local atmospheric density. It increases from the beginning of launch until the point of "max q" and then decreases as the density of the atmosphere drops off with altitude. Most launch vehicles experience "max q" somewhere between 11 and 14 km of altitude (36,000-46,000 ft). If you began detonating the bombs any lower than that, the stress from both the dynamic pressure and the detonations would be such that you'd need to add an exceptional amount of weight in structural reinforcement. And, of course, the heavier the vehicle, the more energy and propellant is required to achieve orbit. And adding propellant increases weight...and you end up in a vicious circle. This is not to say that it couldn't be overcome, but it is one of the key constraints that engineers must contend with when designing launch vehicles.

[Demarquis]

Nuclear pulse is a terrible way to take off from an Earth sized planet. Putting two different drives on the same space craft is terribly inefficient. The obvious solution is two different craft: one to take the crew into orbit, another to launch from orbit to the destination.

Extending this same logic, spacecraft should have either STL drives or FTL, but not both.