How advanced realistically would be human space travel today?

[Marek_Gutkowski]

I have been, trying to create my first serious piece of original fiction.

Here is the premise:
In 1970 telescopes detect a spaceship decelerating in the Oord cloud. It parks itself in Neptune's orbit and sits there minding its own business. The ship does not try to contact humanity.
If an unmanned space probe gets near it a smaller ship shows up grabs it and the probe is never heard of again.

The whole of humanity panics.
Space industries and space exploration is kicked into overdrive.

Every idea no matter how stupid gets funding somewhere on the planet.
So Orion drive, fission pulse engine get a go-ahead and atmospheric test ban treaty gets an exemption.
A liquid core open cycle fission engine will be built.
Big dumb boosters rockets that make the Sea Dragon look tiny are bread and butter.
Orbital loops are attempted.
Orbital cyclers are implemented.
Every hard Sci-fi idea that is physically possible gets a green light.

And naturally, the military gets in on the action. AWACS space stations are being put in orbit. Flac gun emplacements and SAM sites are being planned to be put on the moon.
Gun satellites, CIWS satellites, Missile battery satellites, laser satellites, and whatever-else-can-be-dreamt-up-to-defend-from-the-unknow-alien-threat satellites are being put in orbit.
Everything becoming Casaba Howitzer armed is my current idea. Casaba Howitzer is a nuclear shape charge. A nuke that channels most of its power at a target far away.
So missiles are casaba howitzer tipped, the this are put on excentric orbits to act as mines. They are on all 4 L points around Earth and every planet you can get to as well as on solar orbits.
But I am not married to the idea. If nuclear-pupped X-ray lasers are somehow superior that what it will be. Or something I haven't heard about but you did is more practical. Then my story will have that in it as well.

As that amount of hardware in space needs maintenance and whatnot long-duration human space habitation is a requirement so Skylab Mir and later on far larger and more complex space stations are a necessity.


The actual story will be centered around an MC that was the first to discover the engine plum of the alien ship. We will follow the said MC from being a naive college student in 1970 all the way to being an old soul by 2020(-ish).
So 50 years of money people and resources are being put into space exploration.


What would we realistically have? Any idea is welcome.

 

[Rufus Shinra]

Someone played Terra Invicta recently, I see. Not an issue, it's a great game.

Under SB competence rules?

Spoiler

More likely, though, it'll become quite obvious to everyone that chemical-powered guns are a waste of space for anything outside desperate point defence against bad quality projectiles. Expect tons of nuclear missiles and possibly some mass drivers on Luna, as well as pretty damn large telescopes to keep track of the aliens (that might be a joint project between East and West, if only because it can be targeted only at areas not taken over by Earth powers). Orion drives are cool, but then not necessarly that great for functional warships, especially if you need a bunch of them, so we might see by the Nineties or later some first attempts at a nuclear thermal drive ship or two. The video below shows what is probably the best we can realistically hope to achieve.

 

[Marek_Gutkowski]

Someone played Terra Invicta recently, I see. Not an issue, it's a great game.

Kerbal Space Program actually.

Don't laugh.
Simplified orbital dynamics in that game made me start thinking about the new challenges space combat would entail.
Light lag was present in some popular fiction, but Delta-V rarely is.

Under SB competence rules?

As funny as that would be, I doubt anti-matter could be produced in quantities sufficient for anything that a laboratory experiment. At least not in the 50 years this story would take place in.
For the same reason, Alqubiere Warp drive is not in the story. It will be mentioned but just as a joke where the person that came up with it would be shouted down for suggesting negative energy as a valid engineering calculation.
Negative energy is about as valid a concept as negative velocity is.

More likely, though, it'll become quite obvious to everyone that chemical-powered guns are a waste of space for anything outside desperate point defence against bad quality projectiles. Expect tons of nuclear missiles and possibly some mass drivers on Luna, as well as pretty damn large telescopes to keep track of the aliens (that might be a joint project between East and West, if only because it can be targeted only at areas not taken over by Earth powers). Orion drives are cool, but then not necessarly that great for functional warships, especially if you need a bunch of them, so we might see by the Nineties or later some first attempts at a nuclear thermal drive ship or two. The video below shows what is probably the best we can realistically hope to achieve.

True.
About chemical-powered weapons. However, I think there would be niche uses for those.
Not as a weapon system but as quick means to deploy something. The humans in the story will not know how the weapons the aliens use work.
They will assume they use what they use. So particles or photons, putting out a cloud of flak burst that would act as a deployable ablative armor can be something that is pursued.

As for fission pulse engine/Orion drive, I also have my doubts it could be used as a propulsion method for a spaceship. But it being a surface-to-orbit delivery method is actually promising.
You want to put a whole ore refinery on the moon, or enough solar arrays to power a nation electrical grid in on go. I don't think there is a better solution.

 

[Rufus Shinra]

Kerbal Space Program actually.

Don't laugh.
Simplified orbital dynamics in that game made me start thinking about the new challenges space combat would entail.
Light lag was present in some popular fiction, but Delta-V rarely is.

The best reasonably accessible answers are to be found in Children of a Dead Earth and Terra Invicta, with the former being very hard sci-fi and the second hard-ish. Also, I won't laugh at anyone playing KSP, or maybe laugh WITH them as they go through the same mess we all did.

As funny as that would be, I doubt anti-matter could be produced in quantities sufficient for anything that a laboratory experiment. At least not in the 50 years this story would take place in.
For the same reason, Alqubiere Warp drive is not in the story. It will be mentioned but just as a joke where the person that came up with it would be shouted down for suggesting negative energy as a valid engineering calculation.
Negative energy is about as valid a concept as negative velocity is.

It's Terra Invicta's endgame tech, still very possible but achieved relatively quickly (25-50 years ingame). Technically, if you want to have remotely useable quantities of AM to arm weapons in-game, you pretty much need to spam stations around Mercury to go full Dyson swarm and power large supercolliders 24/7/365 on producing antimatter there using terawatt to petawatt of solar power.

True.
About chemical-powered weapons. However, I think there would be niche uses for those.
Not as a weapon system but as quick means to deploy something. The humans in the story will not know how the weapons the aliens use work.
They will assume they use what they use. So particles or photons, putting out a cloud of flak burst that would act as a deployable ablative armor can be something that is pursued.

That's a reasonable take indeed. In COADE, ablative armour is indeed used to reduce the effectiveness of laser and nuclear weapons through diffusion/diffraction. Though the effectiveness of a "flak shell" (it'd more likely be a gas container to do what you suggest) would still be very limited and possibly not worth the mass cost.

As for fission pulse engine/Orion drive, I also have my doubts it could be used as a propulsion method for a spaceship. But it being a surface-to-orbit delivery method is actually promising.
You want to put a whole ore refinery on the moon, or enough solar arrays to power a nation electrical grid in on go. I don't think there is a better solution.

For surface to orbit, possibly. Getting the initial Luna refineries is indeed a major chokepoint.

Your questions and interest, though, make me say once again that you would REALLY love Terra Invicta, as it's very much what you're considering, except starting in october 2022 and also discussing the political mess on Earth itself:

Spoiler

 

[Aetherius]

Well, taking a look at the Scenario and also at For All Mankind, i would say, similar to FAM but on Steroids.
More Spacestations, maybe orbital Shipyards. Spaceships armed with electrochemical Weapons and Missiles, nuclear powered.

Layered defenses around Moon and Earth and further Layers ourwards.

Plattforms armed with nuclear Missiles ready to launch. Telescopes and other Sensores dotting the sky.

TBH, i wouldn´t be surprised if we would see by 2000 a Mankind quite similar to that of Expanse.

Development in various departments would lead to a higher standard of Living. I wouldn´t be surprised to see E-Cars are the standard by 2000
Maybe we would see the beginning of the construction of a Orbital Elevator. Sure, Bulk Freight would be transported with largers version of the Sea Dragon.
But over time you could ship more tonnage to orbit with a OE.

Also armed Colonies on Moon and Mars.

 

[Marek_Gutkowski]

The best reasonably accessible answers are to be found in Children of a Dead Earth and Terra Invicta, with the former being very hard sci-fi and the second hard-ish. Also, I won't laugh at anyone playing KSP, or maybe laugh WITH them as they go through the same mess we all did.

I am reading Atomic Rockets webpage for inspiration on the technical side of things.
As for KSP...
My Jeb is still orbiting the sun, and I don't know how to get him back.

It's Terra Invicta's endgame tech, still very possible but achieved relatively quickly (25-50 years ingame). Technically, if you want to have remotely useable quantities of AM to arm weapons in-game, you pretty much need to spam stations around Mercury to go full Dyson swarm and power large supercolliders 24/7/365 on producing antimatter there using terawatt to petawatt of solar power.

That's a reasonable take indeed. In COADE, ablative armour is indeed used to reduce the effectiveness of laser and nuclear weapons through diffusion/diffraction. Though the effectiveness of a "flak shell" (it'd more likely be a gas container to do what you suggest) would still be very limited and possibly not worth the mass cost.

For surface to orbit, possibly. Getting the initial Luna refineries is indeed a major chokepoint.

Your questions and interest, though, make me say once again that you would REALLY love Terra Invicta, as it's very much what you're considering, except starting in october 2022 and also discussing the political mess on Earth itself:

I will look up Terra Invicta. Thanks.

Well, taking a look at the Scenario and also at For All Mankind, i would say, similar to FAM but on Steroids.
More Spacestations, maybe orbital Shipyards. Spaceships armed with electrochemical Weapons and Missiles, nuclear powered.

Layered defenses around Moon and Earth and further Layers ourwards.

Plattforms armed with nuclear Missiles ready to launch. Telescopes and other Sensores dotting the sky.

TBH, i wouldn´t be surprised if we would see by 2000 a Mankind quite similar to that of Expanse.

Development in various departments would lead to a higher standard of Living. I wouldn´t be surprised to see E-Cars are the standard by 2000
Maybe we would see the beginning of the construction of a Orbital Elevator. Sure, Bulk Freight would be transported with largers version of the Sea Dragon.
But over time you could ship more tonnage to orbit with a OE.

Also armed Colonies on Moon and Mars.

I think the expanse is way off.
2001: A Space Odyssey level by the story's end would be as ambitious as I would dare to go. Discovery had a gas core fission engine in the book.
As for FAM.
I would try not to make comparisons to that show.
Because in my story the incentives are quite diffrent. FAM was about one upping the other guy on Earth. In my story Evil Empire A will quite happily cooperate with Evil Empire B.
So one country makes a habitation module and the other makes the rocket.
Or one country will use its Orion Drive launch vehicle to deliver the solar panels and radiators to Earth L-point where the second country will assemble the laser, to power a third country's ion drive ship.
The ion drive ship will have large solar panels that will be powered by an orbital laser. Basically a space tram car. The engine is there but the power supply is remote.
Why the extra step and not just use a solar/photon sail? We want the ship to get back to Earth.

As for an armed colony on Mars. It sounds fun but I don't see the point. I could see a manned mars mission(and I just figured out the name for it MMM or M&Ms) but it would be something like a polar station on Earth.
Actually arming it sounds cost prohibitive. Armed with nukes, you need to ship the nukes there, and the missile needed for the nuke to be useful. If the armament is a laser then you either need thousands of tons of solar panels, to power it, or you need to ship a big nuclear reactor to Mars. I doubt there would be time to ship mining equipment and refining gear to source uranium locally.
Also strategically there is little incentive for a Mars colony. Earth would not be able to support it if there is a shooting war. Mars would not be able to support Earth.
The idea of making humanity a multi-planetary species also would not fly. If the aliens turn out to be hostile then if Earth is threatened then Mars is not even an issue.

Mars's surface area is 144.37×10 to the power of 6 km square. Let us be generous and say that our defense system can cover one million square kilometers. And that translates to a little under 570km range on Mars So we need to put 144 defense systems on mars to get full coverage.
And you do need full coverage because if you don't the enemy can just land on Mars outside your defense coverage and start lobbing rocks at you with a space catapult.

And even if you have full coverage of Mars's surface the enemy can just throw rocks at you from the asteroid belt.

So to defend Mars you would need the same asteroid redirect program Earth would need to defend itself.
Moon on the other hand is easier. It is close enough to use the same sensor net Earth uses. And redirecting asteroids that would hit the Moon and Earth can be done by the same program.
Moon is also close enough that lasers and missiles on the Moon can be under the same command as Earth's weapons.


As for orbital shipyards.
If the people on earth are willing to fire off hundreds of nukes to launch large masses to orbit. I don't see the point of having an extra step with orbital assembly.
Yes, there will be an orbital assembly but it will be like the ISS and Mir were made. They assembled themselves no need for a shipyard.

The large scope of the whole endeavor will bring more variety to the launch systems. Most people can name most of the launch systems from the last 50 years. But I would be hard-pressed to name all the cargo airplane manufacturers from the last 50 years. There is a demand to build rockets. So anyone with a pocketbook big enough can try their hand at space. So there will be a IKEA-made rocket with Nokia Avionics and control surfaces from IFA (Industrieverband Fahrzeugbau they don't exist anymore) flying to space by 1980s.
For that reason, civilian space programs would quite common. Just buy an R-7 or a Titan rocket and start launching.

Just like the abundance of C-47 cargo planes made starting an airline in the late 1940s early 1950s so will the surplus of rockets allow civilian enterprises to flourish.
IRL there was never a surplus of C-130 and An-12 cargo planes. But here when R-7 and Titan become obsolete as big space agencies are moving to second gen rockets Saturn V and N1 and then over to third gen like Ariane 5 and Energia. Those last two were made in the 80s. By the 1990's even those would be pushed out of service.
With the constant demand for bigger and better rockets I don't see why a chemical rocket that can launch 1000t into orbit by 2020 would be unfeasible.
And considering chemical rockets have around 2,5% payload fraction or 1-40 then that hypothetical rocket would have 40 000t take of weight.
Yes, a WWI battleship size, or a decent-sized skyscraper.

And that brings me back to why the Moon will be a big focus. On the moon, a chemical rocket payload fraction is circa 50%. So by volume a space rocket on the moon would be cheaper to run that jet plane on earth is.

As for the layered defense idea.
A good idea, but very hard to implement.
You can put all the needed sensors for it. Optical and infrared telescopes would give a 720 degrees of vision in the solar system. Every time an alien spacecraft turns its engine on it will be spotted.
The problem as I see it, is that you have binoculars but you are armed with a rock.
So standing in a field you can clearly see someone walking about. But you can't really do anything about it. You can start running in their direction but they can just run away.

Rocket equation is a bitch.
The theoretical liquid core open cycle engine can give us the delta-V of a Saturn V out of 300kg of propellant. It is still a far cry from Expense magic engine tech.

 

[Marek_Gutkowski]

Children of a Dead Earth and Terra Invicta

I am familiar with Children of a Dead Earth. It was recommended by Atomic Rocket for having N-body physics. KSP for all its complexity uses spheres of influence. So it doesn't have LaGrange points.

As for Terra Invicta. I didn't buy it but I did watch a few YT gameplay videos.
It is sort of adjacent to what I am trying to do in my story, but not quite the same.

What I found interesting is the concept of faction in the game.
In my story, it is the military and the military-industrial complex pushing for rapid expansion of space capability. The scientists are silent partners in this as the expansion of the space industry will let them get prestige from the work they were doing and funding for their own programs.
The in-universe opposition to that are politicians that want to get funding for social programs, the expansion and if that fails, suitable funding for the upkeep of the infrastructure, and education.
There were also your, run-of-the-mill hippies. A pacifist movement that thinks the government want expand war to the stars. They believe diplomacy and coexistence is the only path forward.

Terra Invicta has people that want to genocide/xenocide the aliens and they don't care how many people will die along the way.
People that want to build a unified humanity who is able to repel the aliens if they become a threat or at least get them to a negotiating table. (yes those are two factions in game but the end goal is similar enough)
People that are playing civilization and what a spaceship victory.
People that want to surrender.
People that want to be subjected( ok even I think that is stupid)
And your run-of-the-mill opportunists.

So the game has more opposing and varied world views than what my story had.
I will have to think about it. I don't just want a death cult because that was been done already.

But I like to say, this story is not SB or Stardestroyer net humanity fuck yeah! story.

That is just not a part of my culture. My history book is not about how we won everything and forever because we made more stuff than the rest of the world combined, nor about how we always won because we had more people.
I'm not American.


So don't expect anyone yelling "YeeHAA!" riding a nuke, but more along the lines of
"It is a tale
Told by an idiot, full of sound and fury,
Signifying nothing."

The tone I am aiming for is of a game of chess where you do not see the other player's board or pieces.
The plans and motivations of the aliens can only be guessed and speculated at.

Humanity is working under the maxim of "Si vis Pacem para Bellum" If you want peace prepare for war.

 

[Rufus Shinra]

I am familiar with Children of a Dead Earth. It was recommended by Atomic Rocket for having N-body physics. KSP for all its complexity uses spheres of influence. So it doesn't have LaGrange points.

As for Terra Invicta. I didn't buy it but I did watch a few YT gameplay videos.
It is sort of adjacent to what I am trying to do in my story, but not quite the same.

What I found interesting is the concept of faction in the game.
In my story, it is the military and the military-industrial complex pushing for rapid expansion of space capability. The scientists are silent partners in this as the expansion of the space industry will let them get prestige from the work they were doing and funding for their own programs.
The in-universe opposition to that are politicians that want to get funding for social programs, the expansion and if that fails, suitable funding for the upkeep of the infrastructure, and education.
There were also your, run-of-the-mill hippies. A pacifist movement that thinks the government want expand war to the stars. They believe diplomacy and coexistence is the only path forward.

Terra Invicta has people that want to genocide/xenocide the aliens and they don't care how many people will die along the way.
People that want to build a unified humanity who is able to repel the aliens if they become a threat or at least get them to a negotiating table. (yes those are two factions in game but the end goal is similar enough)
People that are playing civilization and what a spaceship victory.
People that want to surrender.
People that want to be subjected( ok even I think that is stupid)
And your run-of-the-mill opportunists.

So the game has more opposing and varied world views than what my story had.
I will have to think about it. I don't just want a death cult because that was been done already.

But I like to say, this story is not SB or Stardestroyer net humanity fuck yeah! story.

That is just not a part of my culture. My history book is not about how we won everything and forever because we made more stuff than the rest of the world combined, nor about how we always won because we had more people.
I'm not American.


So don't expect anyone yelling "YeeHAA!" riding a nuke, but more along the lines of
"It is a tale
Told by an idiot, full of sound and fury,
Signifying nothing."

The tone I am aiming for is of a game of chess where you do not see the other player's board or pieces.
The plans and motivations of the aliens can only be guessed and speculated at.

Humanity is working under the maxim of "Si vis Pacem para Bellum" If you want peace prepare for war.

Resistance player then. SB and 'I want to kill the Lampreys' is Humanity First, and the astronaut in the pic I posted before is colonel Hanse Castillo, their leader. What's interesting is that all factions have good characterization when you play them, with the tech blurbs being very reminiscent of SMAC for the leaders' descriptions.

 

[Marek_Gutkowski]

Resistance player then. SB and 'I want to kill the Lampreys' is Humanity First, and the astronaut in the pic I posted before is colonel Hanse Castillo, their leader. What's interesting is that all factions have good characterization when you play them, with the tech blurbs being very reminiscent of SMAC for the leaders' descriptions.

You could say that but I wouldn't.
It is not the driving philosophy.
In story it is more like giving Lockheed-Martin carte blanche because they promised they could make us safe from the unknown.
But the LM acts like Omni Consumer Corp from Robocop.
"We got a full production order and 20 years support and maintenance contract! Who cares if it works or not!!!"

 

[Arius]

I think the expanse is way off.

Hm... Overall, your reasoning is pretty good but I wouldn't count that one off just yet.

Of course, the level of humanity's development is unreachable within your timeframe. That's a given.

But you still can take inspiration from The Expanse nonetheless. One thing I don't think you mentioned is that it would definitely be feasible to deploy unmanned mobile platforms (linked to various telescopes and satellites for target acquisition) equipped with nuclear missiles.

Why? Because once in position at certain locations to optimize strike time to a potential incoming threat, they can act as a first strike capability.

It's similar to the MCRN mobile platforms (albeit not as advanced) in The Expanse and doable:

MCRN Stealth C ballistic missile platform

The Stealth C Ballistic Missile Platform[1] is a first strike nuclear missile stealth platform class utilized by the Martian Congressional Republic Navy (MCRN) to launch nuclear assaults against Earth and/or Luna. Five were positioned against Earth during the UN-MCR War. It is one of the most...

expanse.fandom.com

Your various Earth governments would definitely invest and made some progress in fields like robotics and AI, the extent of which you'll have to figure out.

 

[Rufus Shinra]

Hm... Overall, your reasoning is pretty good but I wouldn't count that one off just yet.

Of course, the level of humanity's development is unreachable within your timeframe. That's a given.

But you still can take inspiration from The Expanse nonetheless. One thing I don't think you mentioned is that it would definitely be feasible to deploy unmanned mobile platforms (linked to various telescopes and satellites for target acquisition) equipped with nuclear missiles.

Why? Because once in position at certain locations to optimize strike time to a potential incoming threat, they can act as a first strike capability.

It's similar to the MCRN mobile platforms (albeit not as advanced) in The Expanse and doable:

MCRN Stealth C ballistic missile platform

The Stealth C Ballistic Missile Platform[1] is a first strike nuclear missile stealth platform class utilized by the Martian Congressional Republic Navy (MCRN) to launch nuclear assaults against Earth and/or Luna. Five were positioned against Earth during the UN-MCR War. It is one of the most...

expanse.fandom.com

Your various Earth governments would definitely invest and made some progress in fields like robotics and AI, the extent of which you'll have to figure out.

Heh, forget about stealth in space the instant the other side establishes a decent network of sensors. No matter how discreet you are, the IR emissions will still be pretty visible against the background, plus whatever drive you used to get the deltaV in each maneuver will also be detected.

 

[Arius]

Heh, forget about stealth in space the instant the other side establishes a decent network of sensors. No matter how discreet you are, the IR emissions will still be pretty visible against the background, plus whatever drive you used to get the deltaV in each maneuver will also be detected.

I'm not talking about the stealth aspect of this because you're right, once you ignite the drive, you'll be clearly visible regardless of what powers the ship/platform.

My point was pretty much that once launched and in position (whether fixed or on a predefined trajectory), the platform wouldn't be distinguishable from the background.

And since there wouldn't be anything remotely human out there, once these platforms detect a heat signature close enough, they could launch an entire salvo of MIRV warheads before being destroyed.

But yeah, like everything else, these platforms would be exposed the moment their drives go active. Hence, the idea of minimising such events to keep them as hidden as possible.

 

[Rufus Shinra]

I'm not talking about the stealth aspect of this because you're right, once you ignite the drive, you'll be clearly visible regardless of what powers the ship/platform.

My point was pretty much that once launched and in position (whether fixed or on a predefined trajectory), the platform wouldn't be distinguishable from the background.

And since there wouldn't be anything remotely human out there, once these platforms detect a heat signature close enough, they could launch an entire salvo of MIRV warheads before being destroyed.

But yeah, like everything else, these platforms would be exposed the moment their drives are activated. Hence, the idea of minimising such events to keep them as hidden as possible.

Assuming the platform would somehow be cold enough to be undistiguishable from the background while in stand-by mode - very questionable assumption - the issue is... how do you even put it into position in the first place? You gotta launch it, you have to circularize its heliocentric orbit, etc., which are very, very visible things all of them. These platforms would most realistically be tracked the moment they are deployed.

 

[Arius]

Assuming the platform would somehow be cold enough to be undistiguishable from the background while in stand-by mode - very questionable assumption - the issue is... how do you even put it into position in the first place? You gotta launch it, you have to circularize its heliocentric orbit, etc., which are very, very visible things all of them. These platforms would most realistically be tracked the moment they are deployed.

Yep.

Which holds true for anything we sent out there.

But that's the author's problem.

My point was that, in theory, we can deploy such platforms. From a purely conceptual point of view, it's doable. Keeping it hidden however... Without a half-arsed excuse, an alien civilization capable of coming here wouldn't be remotely terrified by whatever we sent out there and be able to track them. Be it spaceships, satellites, mines (by tracking the delivery vehicle)...

The only weapons they wouldn't be able to detect are land-based weapons.... But that's assuming they come close to destroy us. They don't need to. They can just toss a large number of medium and large rocks our way and be done with it.

 

[Marek_Gutkowski]

-snip-

I love The Expanse.

I am of the opinion it is the Star Trek of our generation. It was highly influential and will be the poster child of good Sci-Fi for decades to come.
Just like Leonard Nemoy had scores of stories of fans coming up to him and telling him his character on the TV show inspired them to enter STEM fields, I know Dominique Tipper will have similar interactions in 20 years' time.


Unmanned platforms are a part of the story.
Just like most satellites are unmanned.
Currently out of around 3000 artificial satellites only 2 are manned.
Out of 109 missions to the moon as of today, only 6 were manned.
Out of over 30000 rockets launched into space 367 were manned.
It is actually hard to guess how many space rockets there were. The number is somewhere between 30000-50000 depending on who you ask or how you count them.

The majority of satellites will be unmanned. The manned space stations will be command and control and support structures to mostly unmanned satellites.

As for robotics and AI. I don't know if there would be anything more impressive in the field that we have IRL. Both of those were developing with breakneck pace and I don't think it you could turbo charge it anymore.

Why? Because once in position at certain locations to optimize strike time to a potential incoming threat, they can act as a first strike capability.

As for the first strike.
They are around Neptune we are on Earth.
The highest Earth orbit you can achieve is around 200 000km. After that, the moon's gravity will become a factor and you no longer are in earth orbit but in moon-earth transit orbit. Or we are looking at Lagrangian points.
Out of the five L points only 4 and 5 are stable so whatever you put there will stay there. They are the same distance from Earth and the moon so 380000km.
There are also Earth-Sun L4 and L5. Unlike the Earth-Moon L points, they are 1500000km away from Earth.
That is an 8-minute communications lag.

Why am I talking about Lagrangian points?
Because everything else will not stay put.

The closest planet to Earth, Venus is not actually always the closest one in absolute terms, Mercury actually is usually closer to Earth than Venus is.
And that closest planet to us is anywhere between 77 million km to 222 million km. Venus is between 38 million and 261 million km.

So weapon platform or sensor platform you put anywhere else that Earth orbit, Earth-Lunar transitional orbit, or the L4 or L5 point, that installation will not be anywhere useful 99% of the time.

Yep.

Which holds true for anything we sent out there.

But that's the author's problem.

My point was that, in theory, we can deploy such platforms. From a purely conceptual point of view, it's doable. Keeping it hidden however... Without a half-arsed excuse, an alien civilization capable of coming here wouldn't be remotely terrified by whatever we sent out there and be able to track them. Be it spaceships, satellites, mines (by tracking the delivery vehicle)...

While there is no stealth in space keeping your space weapons hidden is not that hard.
But it would be done with camouflage and decoys.

The alien would need to get really close to a satellite to figure out if its a camera with a solar panel or a nuke-pumped X-ray laser with a solar panel.
Or even if its is a piece of aluminum foil that pretends to be a solar panel.

On the moon, you can distribute metal lids that look like missile silos but are just metal lids. Or you can put nukes under those metal lids to propel them at an alien if its craft decides to get near it.

You can, and would probably want to, make it look that Earth-Moon system has a gun behind every blade of grass and every rock.

 

[Arius]

As for the first strike.
They are around Neptune we are on Earth.
The highest Earth orbit you can achieve is around 200 000km. After that, the moon's gravity will become a factor and you no longer are in earth orbit but in moon-earth transit orbit. Or we are looking at Lagrangian points.
Out of the five L points only 4 and 5 are stable so whatever you put there will stay there. They are the same distance from Earth and the moon so 380000km.
There are also Earth-Sun L4 and L5. Unlike the Earth-Moon L points, they are 1500000km away from Earth.
That is an 8-minute communications lag.

Why am I talking about Lagrangian points?
Because everything else will not stay put.

The closest planet to Earth, Venus is not actually always the closest one in absolute terms, Mercury actually is usually closer to Earth than Venus is.
And that closest planet to us is anywhere between 77 million km to 222 million km. Venus is between 38 million and 261 million km.

So weapon platform or sensor platform you put anywhere else that Earth orbit, Earth-Lunar transitional orbit, or the L4 or L5 point, that installation will not be anywhere useful 99% of the time.

I am very aware. But I don't know the details of your fiction, what capabilities Earth has achieved, etc. So I remain overly vague, hence the "whether fixed or on a predefined trajectory" part.

The alien would need to get really close to a satellite to figure out if its a camera with a solar panel or a nuke-pumped X-ray laser with a solar panel.
Or even if its is a piece of aluminum foil that pretends to be a solar panel.

Nope, they don't. They don't care about what kind of satellites we have, whether it's merely a "spy satellite" or a weapon platform, they'd just destroy it and keep moving.

They can just destroy safely at a distance. Just like they can destroy Earth at a distance.

If they're capable of interstellar travel, they're capable of things far beyond our capabilities. They don't have to maintain secrecy over their capabilities or think "Uh oh, is it a decoy or not?". Let's assume it is a decoy, they'd use whatever weapons they have to destroy it, yes. Then what? Even if we discover whatever weapons they have, it wouldn't enable us to defend ourselves anyway.

If you want a realistic plot involving an alien invasion, there's only two ways it can unfold:
- They either destroy us from a safe distance
- Or, if they're nice enough to keep us alive, it's pretty much the scenario of the TV series Colony: every defenses on and above Earth would be destroyed in mere hours. Then it's slavery again yayyyy!

 

[Marek_Gutkowski]

I am very aware. But I don't know the details of your fiction, what capabilities Earth has achieved, etc. So I remain overly vague, hence the "whether fixed or on a predefined trajectory" part.

At the start it is the Earth of the year 1970, the Apollo program is ongoing. The Cray-1 80MHz Supercomputer is 6 years away. The Saturn five is be best launch vehicle in existence and the N1 is happily blowing up on the launch pads

If you want a realistic plot involving an alien invasion, there's only two ways it can unfold:
- They either destroy us from a safe distance
- Or, if they nice enough to keep us alive, it's pretty much the scenario of the TV series Colony: every defenses on and above Earth would be destroyed in mere hours. Then it's slavery again yayyyy!

Actually neither.
I won't say what I have planned in the story is an entirely new idea. It is borrowing ideas from many great stories.
But it is neither of the two you mentioned.


As for the aliens.
They are advanced but I did put hard limits on them. There is no faster-than-light communication or propulsion, no artificial gravity, they use the same EM spectrum to see space just like we do.
Their ships have acceleration and DeltaV limits, and they use fuel and need resources. They fly around in rockets not flying saucers.