/tech/ - Technology

seems useful only for reaching the outer planets. using solar panels gets you to Mars but after that power gets much much harder to come by

What is the purpose of having a nuclear reactor if you're using chemical propulsion anyway?
>t. brainlet

>>10631
It's not feasible to generate as much energy as is required for electric thrusters with chemical energy sources.
>Tracing its roots to the dawn of the Space Age, the TEM concept is attempting to marry a nuclear reactor with an electric rocket engine. The electric propulsion systems heat up and accelerate ionized gas to create a thrust-generating jet and, therefore, are alternatively known as ion or plasma engines. When measured per unit of spent propellant mass, electric engines are more efficient than traditional liquid or solid-propellant rockets, but their thrust is relatively low at any given time and they require a great deal of electric power to operate.
https://www.russianspaceweb.com/tem.html

>>10632
I see, they're using chemical for the first stage (duh), not for actual space travel

>>10628
>so it's less hardcore than direct nuclear propulsion like an Orion-drive
Orion is based on nuclear pulses, but you can get hardercore by using a nuclear-salt-water thruster that rides a continuous nuclear detonation wave.

>>10631
Nuclear engines burn low and long, chemical engines burn hot and short. Chemical rockets to get into orbit because gravity's a bitch, nuclear engines for long haul travel.

Those have existed for literal decades

The problem with them is that rockets are generally unsafe compared to planes and prone to exploding, keeping such reactive substances like uranium on a rocket causes the risk of accidents to accelerate not to mention most modern rockets have multiple engines, ones for launch off earth the others for space travel and the rest for a variety of different reasons

>>10971
>The problem with them is that rockets are prone to exploding
There are already nuclear satellites and nuclear probes, how was that handled ?

>>10972
>There are already nuclear satellites and nuclear probes
and yet no nuclear bomb ;)

When the Space Shuttle was being designed in 1969, the decision was made to have the two solid-rocket boosters made at Thiokol in Utah, and they were to be transported to the Florida launch-site by train. This meant that their diameter was limited by the width of the railroad tunnels along the way. The tunnels were very expensively dug out of the rocky mountains to barely fit the locomotives back in the 1800’s.

The width of the modern locomotives was dictated by the width of the two rails on the train tracks, made to fit the older steam locomotives. The two rails for the older locomotives were spaced to match the horse-drawn wagons of the day, since hundreds of trails across the US had been forced to use dynamite to barely remove just enough large boulders from tight passes. By using an existing trail width, it saved on extra work and cost.

Wagons had been built to a width that set the wheels into common road ruts that had been worn into the trails for decades, helping them to avoid sliding off to the side in slippery conditions. But…who decided on the best width of the early wagons in the western expansion? Wagons were built to the width of two side-by-side horse-butts. A narrower wagon with the horses in-line would be unstable, prone to flipping onto their side. And wider wagons would not fit narrow trails.

The diameter of the space-shuttle solid rocket boosters is the width of two horse-butts.

NASA had a working nuclear engine in 1969 but it was cancelled by the president. The NERVA engine.

Maybe within a decade we'll finally have what we should have had 60 years ago.

The public (socialist) space program should aim big, for jobs not immediately profitable. In this way progress is not retarded by capitalism. In theory. It worked for the apollo program. But in reality politics usually gets in the way. They were not funded well enough to aim as big as they should, so they scaled back. Scaled back public space programs are half the cost but with none of the advantages. They cost more then private space programs but deliver worse results.

The private (capitalist) space programs can focus on efficiency and sustainability building off of technologies developed by the public space program, and they did, but without the public space programs being well funded they had no big bold expensive public program innovations to build off of and optimize, and they didn't want to risk the capital to do it themselves. So they failed as well.

Had the public space program been well funded, they would have made bigger leaps, giving the private space programs more to work with and make affordable thus further enabling the public programs to go further still.

But politics gets in the way and progress in space stagnated as socialism and capitalism alike failed each other. When they could have gone so far working off each other.

In the end the only way to break the stalemate of stagnation is either a public program given the funding and mandate to aim for the big wins. Or a private space program with the balls to risk capital to aim for the big wins. If one can succeed it can boost the other and get the cycle going again.

Spacex has the balls and they've already pushed ahead and will push ahead further still putting the public space program to shame. But now the public space program can start to rely on the cost efficient private space innovations (reusable rockets) of Spacex as a springboard to enable them to go further then if they had to rely entirely on their own cost inefficient systems (the SLS). Perhaps the cycle can start again leading to massive space progress. Or maybe the public space program doesn't move with the times and keeps rehashing old shit instead of pushing forward, leaving all the innovation to the private space programs hoping they have the balls and capital to take the risks.

>>11069
>The diameter of the space-shuttle solid rocket boosters is the width of two horse-butts.
Maybe it was just good enough that they didn't bother changing it. If legacy standards get in the way too much, people usually change them.

>>11070
This feels like a bait and switch
You began your post by foreshadowing a nuclear rocket engine, and then at the end of it's just Elon's reusable balls.
Lets face it the private sector doesn't have nuclear balls.
They didn't even try nuclear powered container shipping, and that seems like low hanging fruit.

>>11070
Have you seen the cost of the sls? The latest public space heavy rocket, the costs are astronomical. Having nuclear balls is great but not so great when you can barely afford to put any of them into space. Affordable heavy lift rockets are needed, and only elons balls could provide that.

It's the difference between putting one single nuclear ship into space, vs putting 1000 nuclear ships into space. And you're right, for whatever reason private never tried nuclear, and public never tried affordable launch vehicles, which feeds into my point that the two need each other to bring out the best in each other.

>>11073
forgot pic
So these numbers represent the potential for starship at its peak. even in the unlikely event these numbers end up being off by a factor of 10 that would only make the sls 100x more expensive rather then 1000x more expensive. The cost savings would allow public space to focus on making and launching more nuclear ships, maybe hundreds, rather then paying out the ass just to get a couple ships to space. Spacex is going to mass produce the starship like it was an automobile, the plan is for a starship to roll off the assembly line every 72 hours. Every 72 hours a new starship capable of launching 3 times a day every day for years, thousands will be built do you not get it?

People are sleeping on this because they can't wrap their heads around the absolute scale of it, the brain simply refuses to accept it, we've been so conditioned for low expectations, happy with a couple space telescopes every few decades and maybe 2 or 3 rovers on mars, a few flybys. That's not a space age, that's a few toys and some neat pictures.

The approximate total mass to orbit, everything put into space, throughout the entire history of space travel to the present day is roughly 15 million kg. A thousand starships launching 3x a day could put that much mass into orbit in 2 months. 70 years worth of payload capacity in 2 months. 6 times the entire history of man in space every year. 60x times everything put up there so far in a decade.

There is essentially no limit, the public space program won't have to hold itself back anymore. All the space telescopes and space stations and nuclear whatevers, rovers, human colonies. Whatever the fuck we can come up with and build we can now afford to put it up there. That is a space age, and we're on the cusp on it now.

>>11073
>Have you seen the cost of the sls? The latest public space heavy rocket, the costs are astronomical.
It's still private contractors that build this, so the price of this also is about subsidizing private industry.
It's not an actual example of public production because the factories that build it aren't public.

>Having nuclear balls is great but not so great when you can barely afford to put any of them into space.
It's about physics, chemical energy is not very concentrated compared to fission energy. Spacex Starship needs 9 launches to put one Starship into orbit and fully fuel it. (8 fuel launches). And with that it still can't go as far or fast as the nuclear fission powered ion-thruster in OP

>Affordable heavy lift rockets are needed, and only elons balls could provide that.
Spacex is still is de-facto subsidized by the US public. For example US Air-Force payed over 300 million to launch a spy satellite, that's approaching Space-shuttle money. That's no where near the advertised launch-cost price-tag in Spacex marketing material. Even outside of such extreme aberrations Elon Musk promised that reusable rockets would make it 10 times cheaper, but the reality is that reusable rockets economize to the tune of about 10% cheaper. That's a solid efficiency improvement considering that fundamentally it's the same technology that's been used for the last 50 years, but it's also 100 times less savings than what the Musk-fans use in their mental calculus.

It's a strange choice of words to call engineers and workers at spacex "balls"

>>11075
Ok fair point about the private contractors. But if the factories were public would that actually change anything? Governments are famously bad at balancing any kind of a budget. And politics gets in the way to the point where to get approved the programs have to satisfy the demands of multiple politicians.

Spacex Starship will only need multiple launches to go beyond orbit, it can do orbit on its own. Think about it, would need to get into orbit in the first place to be refueled.
>Still can't go as far or fast as the nuclear powered thrusters
That's not the point, how are you getting those nuclear thrusters into space affordably?

The space shuttle cost $54600 per kg to orbit
The Atlas V costs $8100 per kg to orbit
Russias Angara rocket is the second cheapest option at $4000 per kg to orbit (only 2 launches to date)
The Falcon 9 is $2600 per kg to orbit
Falcon heavy is $1500 kg to orbit
https://aerospace.csis.org/data/space-launch-to-low-earth-orbit-how-much-does-it-cost/

You said Spacex is only 10% cheaper, it's more like 70% cheaper.

Any money the us spends on Spacex rockets is SAVING THEM MONEY vs launching the same payloads on other rockets. This means more money for other things.

Meanwhile the Starship is set to be even cheaper then the Falcon 9 by a massively significant factor to the point where it will cost about $20 per kg to orbit. Not a typo, twenty dollars.

>>11076
and the atlas v at $8000per kg is the second cheapest option available to the United States. 10% of $8000 is $800 so when people say spacex is 10x cheaper ok they're wrong, it's only 5x cheaper. But when they say 10x cheaper they're talking about a hypothetical fully reusable falcon 9, a project that was set aside to focus on the much more promising Starship.

>>11076
Of course that $20 per kg is the potential of the Starship program at its hypothetical peak with economy of scale and mass production. It won't cost $20 per kg on the first launch. And even if those estimates are off by a factor of 10 (unlikely) that's still $200 per kg ie 40 times cheaper then Atlas V rather then the projected 400 times cheaper, either way if Starship works, whatever it ends up costing per kg, it's going to be massively MASSIVELY more affordable then anything else.

People like to shit on Spacex because they saw some bullshit ragetubers lying on youtube for clicks and it satisfied them for some reason.