The thread for space cadets!

So a startup raised $40 million to catapult stuff into space.

https://www.geekwire.com/2018/spinlaunch-raises-40m-airbus-google-others-space-catapult/
Wen Hsieh, general partner at Kleiner Perkins, said he and fellow investors were “very intrigued” by the fact that SpinLaunch’s system doesn’t plan to rely on traditional chemical rocket propulsion to get its vehicles off the ground.

“SpinLaunch can be powered by renewable energy sources such as solar and wind, thereby eliminating the use of toxic and dangerous rocket fuels,” Hsieh said. “SpinLaunch’s unique and proprietary approach to place satellites into low Earth orbit is not only highly cost-efficient, but also safe and green.”

Good lord, I must be in the wrong business >_<
These investors will give their money to anyone.

I get that SpinLaunch is in stealth mode and details are scarce, but the odds of this working on Earth are 0% right?
https://en.wikipedia.org/wiki/SpinLaunch
Technology
SpinLaunch intends to develop a space launch technology that aims to reduce dependency on traditional chemical rockets. Instead, a novel technology will use a large centrifuge to store energy and will then rapidly transfer that energy into a catapult to send a payload to space at up to 4,800 kilometres per hour (3,000 mph). If successful, the acceleration concept is projected to be both lower cost and use much less power, with the price of a single space launch reduced to under US$500,000.[2] The speed required to maintain Low Earth orbit is 27,000 kilometres per hour (17,000 mph).
 
IIRC it's impossible to directly shoot stuff into Earth orbit, because moving by inertia it will have to pass through original point it was launched from.
Even not taking air resistance into account, this thing will always either fall back or fly away from Earth.
But if catapult is used only for initial acceleration and after that, spacecraft uses traditional rocket engines, then it may be feasible theoretically. But still the startup looks very doubtful.
 
I get that SpinLaunch is in stealth mode and details are scarce, but the odds of this working on Earth are 0% right?
https://en.wikipedia.org/wiki/SpinLaunch

They might succeed at getting something of the ground, but at that speed it is going to come back to ground pretty soon. If they launched straight up, they wouldn't have enough energy to go beyond 90 km altitude and that is ignoring air resistance (which is most like a huge issue that cannot be ignored). So, no they're not going to send anything to space with that.
 
Aren't you describing a redundancy? Or do you mean that if the whole engine stops working, the shpis is simply designed to work whether 3 engines are on or 8?
That was a poorly written post, apologies. I mean that there are often single points of failures in aerospace, including rocket engines. Not only could a single bad component shut down (or explode) an engine, but almost no rockets have engine-out capability.

A similar example is the 'jesus nut' on helicopters.
Maybe this is throwing a rocket into the sky and using chemical feul rockets, just less of them? It does say "reduce chemical fuel dependence", not eliminate.
I think they're using a hyrodegen-oxygen upper stage. These are environmentally benign fuels that really only require electricity to produce. If you power the whole system with solar, wind, etc, then it is a very green system. I came across an article a few days ago that talked about an upper stage for this but I cannot find it now. :-/


This whole system would compliment bigger rockets like New Glenn or BFR rather than truly compete with them. This system would destroy most (really all) satellites due to insane g loads and vibrations so it won't see much use for that.

What it is phenomenal at is throwing up industrial raw inputs.


Blue Origin has made an explicit goal of building up humanity's space infrastructure. They can launch the factories and manned missions, SpinLaunch can put up the raw inputs to run the factories during the many decades it will take to build a purely-space based mineral-extraction infrastructure to harvest asteroids to run factories. Similarly, BFR can launch a hundred colonists and SpinLaunch can put several years worth of food and medicine for them into orbit.
 
That was a poorly written post, apologies. I mean that there are often single points of failures in aerospace, including rocket engines. Not only could a single bad component shut down (or explode) an engine, but almost no rockets have engine-out capability.

Redundancy means more mass which rapidly makes putting things in orbit prohibitively expensive.
 
Rocket Lab is set to launch their first commercial mission (and third overall) on Friday. I was picked to lead the first contact team to operate our satellite on that launch. Pretty stoked.
 
IIRC it's impossible to directly shoot stuff into Earth orbit, because moving by inertia it will have to pass through original point it was launched from.
Even not taking air resistance into account, this thing will always either fall back or fly away from Earth.
But if catapult is used only for initial acceleration and after that, spacecraft uses traditional rocket engines, then it may be feasible theoretically. But still the startup looks very doubtful.
It is easy, in theory, to shoot something into orbit. The objection is purely practical.

Escape velocity is about 25K mph/40K kph. Anything short of that remains in the gravity well. However, if the trajectory of descent misses the planet you get an orbit. It's that simple. Many orbits are not stable, so the projectile will quickly return to ground. Indeed, no orbit is truly stable. However, putting something up for several orbital revolutions is simply a matter of careful calculation.

The problem is not air pressure, but acceleration. To reach 40K kph in a short acceleration time--hence shot into space--requires heavy acceleration. For example, 10 seconds requires well over 100 g of acceleration. Ten seconds is already unreasonably long. Two seconds requires almost 600 g. Doing this from the moon would be difficult, but possibly practical. There is a famous book about the possibilities.

That book, The Moon is a Harsh Mistress, outlines why this is generally frowned upon. Basically, a launch catapult is also a large piece of artillery. Simply throwing rocks at 40K kph will produce nuclear scale damage at impact.

J
 
It is easy, in theory, to shoot something into orbit. The objection is purely practical.

Escape velocity is about 25K mph/40K kph. Anything short of that remains in the gravity well. However, if the trajectory of descent misses the planet you get an orbit. It's that simple. Many orbits are not stable, so the projectile will quickly return to ground. Indeed, no orbit is truly stable. However, putting something up for several orbital revolutions is simply a matter of careful calculation.
Is it though?
Let's say we shoot a cannonball from the Earth. No atmosphere and no engines. If it stays in the gravity well, its trajectory must be an ellipse which includes the point where it was shot from.

Edit: I mean, if the projectile doesn't hit the ground at some point, it must return precisely back to the cannon from the opposite side.
 
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Didn't read the article, but I saw a headline that stated Trump wants to create a new branch of the military dedicated to assuring American orbital and space dominance. Now I know the idea of militarizing space worries a lot of people, but I don't really have a problem with it. The Russians have their own space branch for their military called the Aerospace Forces. It was created in 2015 and replaced the Russian Air Force (which is now subordinate to the Aerospace Forces). I'm sure the Chinese have plans to do the same as well, so we might as well get on it too before we get completely left behind.
 
It is easy, in theory, to shoot something into orbit. The objection is purely practical.

Escape velocity is about 25K mph/40K kph. Anything short of that remains in the gravity well. However, if the trajectory of descent misses the planet you get an orbit. It's that simple. Many orbits are not stable, so the projectile will quickly return to ground. Indeed, no orbit is truly stable. However, putting something up for several orbital revolutions is simply a matter of careful calculation.

The problem is not air pressure, but acceleration. To reach 40K kph in a short acceleration time--hence shot into space--requires heavy acceleration. For example, 10 seconds requires well over 100 g of acceleration. Ten seconds is already unreasonably long. Two seconds requires almost 600 g. Doing this from the moon would be difficult, but possibly practical. There is a famous book about the possibilities.

That book, The Moon is a Harsh Mistress, outlines why this is generally frowned upon. Basically, a launch catapult is also a large piece of artillery. Simply throwing rocks at 40K kph will produce nuclear scale damage at impact.

J

Is it though?
Let's say we shoot a cannonball from the Earth. No atmosphere and no engines. If it stays in the gravity well, its trajectory must be an ellipse which includes the point where it was shot from.

You cannot put something directly into Earth orbit with a cannon, despite Newton's famous thought experiment. You could shoot something into solar orbit or go directly to the moon (but will need a kick stage to avoid crashing) but you cannot get into Earth orbit without some means for providing a second impulse to circularize the orbit. Launch straight up will either give you an escape trajectory (if it's fast enough) or come straight back down. And has been noted several times, the g load of going directly to an escape trajectory is insane. The g load to go to LEO (with a kick stage at apogee) is similarly insane but slightly less so. In any case this system will have limited utility for launching satellites and no utility for launching people but will be phenomenal for launching raw inputs for factories or colonies.

Didn't read the article, but I saw a headline that stated Trump wants to create a new branch of the military dedicated to assuring American orbital and space dominance. Now I know the idea of militarizing space worries a lot of people, but I don't really have a problem with it. The Russians have their own space branch for their military called the Aerospace Forces. It was created in 2015 and replaced the Russian Air Force (which is now subordinate to the Aerospace Forces). I'm sure the Chinese have plans to do the same as well, so we might as well get on it too before we get completely left behind.
Yeah I'm ok (though not thrilled) with this and it's not nearly as dramatic as it sounds. The USAF already has a space command with about twice as many employees as NASA. They are in charge of a very wide range of responsibilities from controlling launch ranges, to monitoring space junk, to providing TLE's (navigational data) to satellite operators, to operating GPS and weather satellites.

The problem this new Space Force is meant to address (in addition to boosting Trump's ego and polling numbers) is that the space and launch vehicle markets are undergoing a sea change. The pace of innovation has begun to climb an exponential curve* and the current organization of the space command has been very slow to react and adapt to changing circumstances. The hope is that by making it an independent command it can be more responsive to market forces to better serve the public while maintaining vigilance on the defense side by allowing more innovative approaches in military acquisitions of space and launch vehicle hardware. The counter argument is that this will potentially add more bureaucracy to the processes already in place and make the military less responsive.

So far, this won't actually increase the military's presence in space, just reorganize the assets that already exist. If the effort is successful, we will see the launch ranges able to support a higher launch cadence than is currently possible and we will see more military payloads going up as rideshares on commercial satellites as well as a lot of military small satellites. SpaceX alone is already challenging the launch ranges as far as their operational cadence, when Blue Origin and other providers like Rocket Lab hit their stride they will break the military's ability to coordinate and support these launches. Moreover, the USAF spends a god-awful sum** on their military satellites and having them begin to ride the CubeSat revolution will bring down costs even as they increase capabilities.

I think a better proposal would be to turn over a lot of the functions of space command to a civilian agency.


*Remember that until about 5 years ago, basically the entire planet was using rockets with very little changes from the 60's and large, hyper-expensive satellites with similarly slow upgrade cycles. Now they are sending shoe box sized satellites to Mars and landing rockets on their tails like something out of a Heinlein novel. The space age is really just beginning.

**For reference, if NASA had access to the budgets that the USAF and espionage agencies have for their own space efforts, we could launch a Hubble equivalent every 5 years or so.
 
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It's never too early to start preparing for the inevitable onslaught of the moon Nazis.:scan:
 
Didn't read the article, but I saw a headline that stated Trump wants to create a new branch of the military dedicated to assuring American orbital and space dominance. Now I know the idea of militarizing space worries a lot of people, but I don't really have a problem with it. The Russians have their own space branch for their military called the Aerospace Forces. It was created in 2015 and replaced the Russian Air Force (which is now subordinate to the Aerospace Forces). I'm sure the Chinese have plans to do the same as well, so we might as well get on it too before we get completely left behind.
I also want to emphasize this effort doesn't really add to the militarization of space directly. On paper, all this does is reorganize what already exists. If the effort is successful, it will ultimately mean that the military will be able to launch many more cheap satellites instead of small numbers of hyper-expensive assets. Whether this will represent a net increase in militarization (however you care to characterize that) or just a wash is yet to be seen. But the main thrust is not to launch space battleships or whatever.
 
I also want to emphasize this effort doesn't really add to the militarization of space directly. On paper, all this does is reorganize what already exists. If the effort is successful, it will ultimately mean that the military will be able to launch many more cheap satellites instead of small numbers of hyper-expensive assets. Whether this will represent a net increase in militarization (however you care to characterize that) or just a wash is yet to be seen. But the main thrust is not to launch space battleships or whatever.
The military has space assets. Simply putting them under a formal command makes sense. They would also be the ones to handle low or no oxygen pressure situations. We will not have Charlie Sheen dropping from orbit to kill bugs anytime soon.

J
 
Machete for secretary of space defense!
machete_kills_in_space-493588297-large.jpg
 
The problem this new Space Force is meant to address (in addition to boosting Trump's ego and polling numbers) is that the space and launch vehicle markets are undergoing a sea change. The pace of innovation has begun to climb an exponential curve* and the current organization of the space command has been very slow to react and adapt to changing circumstances. The hope is that by making it an independent command it can be more responsive to market forces to better serve the public while maintaining vigilance on the defense side by allowing more innovative approaches in military acquisitions of space and launch vehicle hardware. The counter argument is that this will potentially add more bureaucracy to the processes already in place and make the military less responsive.

The military responsive market forces? I believe that when I see it.

Won't this mostly involve giving new job titles and maybe uniforms to the same people, who make the decisions now? If so, how is that supposed to change anything?

And most importantly: Does that mean that the US will have Space Marines?
 
You cannot put something directly into Earth orbit with a cannon

I don't know about the thought experiment you cited, so how about this thought experiment:

You fire a cannon from Earth with enough force for the cannon ball to leave the gravitational influence of the Earth and get into an orbit around the sun. The cannonball travels around the sun and a couple months (or years or decades or whatever) later ends up passing very close to the Earth. It enters Earth's atmosphere and ends up performing a lithobreaking maneuver, which puts it in an orbit around the Earth (with a periapsis admittedly inside the atmosphere, meaning that the orbit wouldn't last very long)

Several weeks/months later ends up at the apoapsis of its orbit around the Earth and gets a gravity assist from the Moon, altering the periapsis of the orbit and creating a stable orbit.

Ah I think I get it, I guess the problem is that eventually the gravity of the moon will alter the orbit again and you can't guarantee a stable orbit. For that you need some sort of way to alter your velocity vector without using external sources (like lithobreaking through the atmosphere or using the moon as a gravity assist/alterator).

Plus I suppose aiming the cannon properly to make the above scenario happen might not be possible to calculate ahead of time? Plus it seems it would be a crazy powerful cannon

Correct me if any of the above is wrong or if any of my terminology is wrong. I was trying to work through this in my mind but Poland lost in the World Cup so I am not sober
 
The military has space assets. Simply putting them under a formal command makes sense. They would also be the ones to handle low or no oxygen pressure situations. We will not have Charlie Sheen dropping from orbit to kill bugs anytime soon.

J
The USAF hasn't sent up an military astronaut since the shuttle was retired as far as I know. This doesn't change that.
The military responsive market forces? I believe that when I see it.

Won't this mostly involve giving new job titles and maybe uniforms to the same people, who make the decisions now? If so, how is that supposed to change anything?

And most importantly: Does that mean that the US will have Space Marines?
The military is actually trying hard to do just that already. Part of the problem is the re-adjustment is too slow and doesn't seem to capitalize fully on collapsing hardware prices.

Right now the USAF has increased their ability to support more rapid launch cadences - not as far as they need to go but they are trying. They are also on the books to fly the first hosted payloads commercially - that is they buy space on some commercial operator's satellite to host their own payload.


In any case a lot of the other functions the USAF/Space Command have in this arena could easily be shifted to civilian agencies and in a few cases they are trying to do that.

On shifting responsibilities - the theory that this will improve things is that the manned/unmanned aerial operations do not have much in common with space operations. The USAF has not been a super helpful partner in the space arena to commercial operators and in fact don't even manage their own space programs very well. The thinking is that by making this an independent branch it removes many of the competing motives/objectives that undermine the space side and allows true space experts to advance (it can be hard to get promotions and responsibilities in this area when the DoD places so much emphasis on combat commands for promotion eligibility).

It's actually easy to overlook how badly misfit officers can damage the ability of the USAF to function in the space arena - from managing space assets to procuring new ones, they can make a mess of things. It's a bit like taking an admiral and putting him and his cohort of officers in charge of the Army. Sure, there are some things in common but there are enough differences that you really want an expert at the helm and experts filling out the ranks. Space commands don't tend to get that because the kinds of people who are experts in space operations and procurement don't often fight on the front lines and therefore get passed on promotions.

I don't know about the thought experiment you cited, so how about this thought experiment:

You fire a cannon from Earth with enough force for the cannon ball to leave the gravitational influence of the Earth and get into an orbit around the sun. The cannonball travels around the sun and a couple months (or years or decades or whatever) later ends up passing very close to the Earth. It enters Earth's atmosphere and ends up performing a lithobreaking maneuver, which puts it in an orbit around the Earth (with a periapsis admittedly inside the atmosphere, meaning that the orbit wouldn't last very long)

Several weeks/months later ends up at the apoapsis of its orbit around the Earth and gets a gravity assist from the Moon, altering the periapsis of the orbit and creating a stable orbit.

Ah I think I get it, I guess the problem is that eventually the gravity of the moon will alter the orbit again and you can't guarantee a stable orbit. For that you need some sort of way to alter your velocity vector without using external sources (like lithobreaking through the atmosphere or using the moon as a gravity assist/alterator).

Plus I suppose aiming the cannon properly to make the above scenario happen might not be possible to calculate ahead of time? Plus it seems it would be a crazy powerful cannon

Correct me if any of the above is wrong or if any of my terminology is wrong. I was trying to work through this in my mind but Poland lost in the World Cup so I am not sober

I mean I guess this technically could work but no one can plot this kind of trajectory over the timescales required. There are far too many big, moving pieces in the solar system for this to work.
 
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