Mass Limits Apply To SSTOs Even When You Can Build Infinite Thrust Propulsion Engines....

[Spacescifi]

Scifi Scenario: Repeller ray drive exists that emit extremely repulsive scifi rays that repel all mass that it hits. Mirrored nozzles with emitter lenses down the throat is how it looks. No fuel is required, only power. Repeller rays drives are not super hot like photon drives... as they trade energy/heat conversion for energy/extreme repulsive force conversion. That said, they will blast away the ground on liftoff much like an ordinary rocket... just without the heat of a photon drive.

Power source: Powerbanks that can store their mass equivalent of electrical charge, and discharge it in large amounts as energy as well (otherwise it could not power the repeller ray propulsion). So a kilogram powerbank fully charged would weigh 2 kilograms, whereas fully drained it would weigh a kilogram. If overheated a charged powerbank will detonate, releasing all it's stored energy in a catastrophic explosion.

Power generation: The moon has been turned into a scifi solar base, with solar panels covering it to charge vast arrays of powerbanks.

SSTO Question: Possible but surely there will be a mass limit from the designers for public safety reasons.

Examples: The heavier an SSTOs mass, the more energy your powerbank needs to store, leading to larger powerbanks and ultimately a more dangerous outcome if your powerbank overheats and detonates due to a crash or weapons fire hitting it(ka-boom on steroids).

Main Question:  Ship designers can give a ship SSTO as much delta v and thrust as they want, the only question is what amount is reasonably safe for the public. For example a 300 ton SSTO that can do 1g for 2 hours (3g for a third of that) would still have a dangerous bomb of a powerbank if it ever went off.

Conclusion: I think SSTOs would generally be under 1,000 tons, simply because 1,000 tons is more dangerous than the public would want to deal with. So superheavy SSTO freighters I don't see occurring, but 300 tonners is a possibility. As it is... based on previous calculations of power scaling of mass/energy equivalence powerbanks, they would detonate at near Tsar bomb levels anyway... more so if you build heavier and heavier.

Secondary Conclusion: You can totally do van size star trek shuttlecraft SSTOs now... I just expect their powerbanks to be quite limited for public safety... which means limited delta V but good thrust. Like I dunno... 30 min of 3g is good enough to deorbit, land, and go back to the mothership in orbit... once.

Third Conclusion: Missiles would be overpowered in this setting, as you could get ridiculous levels of delta v AND thrust since safety is not a concern for the missile. I am talking 1000g missiles with less than a kilogram of powerbank that is nearly fully charged that can accelerate for an hour. They would also be expensive (since they require a solar paneled covered moon to generate the power to charge them).

 

Thoughts?

Edited November 5, 2023 by Spacescifi

[Shpaget]

5 hours ago, Spacescifi said:

Repeller ray drive exists that emit extremely repulsive scifi rays that repel all mass that it hits. Mirrored nozzles with emitter lenses down the throat is how it looks. No fuel is required, only power.

When you say no fuel, do you mean no reaction mass? So what does it push against? Ground? You can't get to orbit by only pushing up. You need sideways speed.

[Spacescifi]

36 minutes ago, Shpaget said:

When you say no fuel, do you mean no reaction mass? So what does it push against? Ground? You can't get to orbit by only pushing up. You need sideways speed.

 

Repeller rays leave the mirrored nozzle and repel it... and the rest of the ship, in the opposite direction.

The rays reflect off the mirrored nozzle as they leave the emitter, providing thrust.

[Shpaget]

That doesn't work, for the same reason why you can't pick up yourself off the ground.

[Spacescifi]

4 hours ago, Shpaget said:

That doesn't work, for the same reason why you can't pick up yourself off the ground.

It actually would if repeller rays were real.

 

For every action there is a reaction. As you shoot something in one direction that is strongly repelling you, you go the opposite direction. It's a basic of physics really, just taking it to extremes for scifi.

[JadeOfMaar]

12 hours ago, Spacescifi said:

Repeller ray drive exists that emit extremely repulsive scifi rays that repel all mass that it hits.

I easily see this engine's performance being dependent on ambient pressure (as with any air-breathing engine) because in vacuum there is nearly no mass to repel. How does one compensate for this and promise enough thrust (and dV, ultimately) to make it to orbit?

[darthgently]

1 hour ago, Spacescifi said:

It actually would if repeller rays were real.

Checkmate.

[JadeOfMaar]

13 hours ago, Spacescifi said:

If overheated a charged powerbank will detonate, releasing all it's stored energy in a catastrophic explosion.

13 hours ago, Spacescifi said:

as they trade energy/heat conversion for energy/extreme repulsive force conversion

If using the engine (even at full throttle for a very long time) does not produce waste heat, and the ray itself does not produce heat when it hits something, why is there a condition where the battery can overheat and explode? Why then, is there an upper limit of how heavy a such equipped SSTO can be? Give me my 1000+ ton freighter.

[Spacescifi]

9 hours ago, JadeOfMaar said:

If using the engine (even at full throttle for a very long time) does not produce waste heat, and the ray itself does not produce heat when it hits something, why is there a condition where the battery can overheat and explode? Why then, is there an upper limit of how heavy a such equipped SSTO can be? Give me my 1000+ ton freighter.

It DOES produce heat, just not nearly as much as photon drive. The heat it produces is on par with big search lights used in WW2 to scan the skies for enemy aircraft, which is virtually inconsequentual, since that is not enough waste heat to be a bother for the crew or risk detonation.

Spoiler

How powerful were ww2 searchlights?
Powered by a 120-kilowatt generator, these searchlights could detect targets at distances of up to 13 kilometres (8.1 mi). Typically, one 200 cm searchlight was employed with three 150 cm searchlights.

Overheating would occur if powerbanks were hit by high energy weapons fire, or if the ship crashed hard enough that the powerbanks detonate.

 

EDIT: The heat is low enough that it is virtually a non-factor so I did not bother mentioning it.

9 hours ago, JadeOfMaar said:

I easily see this engine's performance being dependent on ambient pressure (as with any air-breathing engine) because in vacuum there is nearly no mass to repel. How does one compensate for this and promise enough thrust (and dV, ultimately) to make it to orbit?

Why? It's dependent on the exotic photons (let's call them quotons) hitting off the nozzle as they are emitted to push it away in the opposite direction.

Which works in vacuum just like it does in air.

Normal photons when absorbed by mass produce heat. Quotons when absorbed by mass cause mass to repel in the opposite direction it is hit from the quotons.

Quoton rays going through the air spread out and weaken their repulsion at a distance, much how a rocket plume won't hurt you nearly as bad at a big enough distance.

Edited November 5, 2023 by Spacescifi