Tim Dodd made a lovely point in his stream of the event.
People keep asking why this is a big deal- we did this fifty years ago, right? It should be a lot easier now with modern tech.
Yes, but now we're doing it safely. The Apollo program took risks that today's NASA never would allow. We're better at that now, but it's a lot more work.
It's not a big deal, because it's so expensive it's a dead end. The problem has always been making human space flight cheap enough that it can lead to activities with positive return. The Apollo and Shuttle eras failed in that respect. SLS, by not reducing launch costs, continues in that sad and aggravating tradition.
The massive cost comes from defeating gravity and getting stuff off of this planet. Cost reductions probably won't happen until the ISS turns into an orbital city with spacecraft manufacturing capabilities. The JWST engineers talked about the importance of building future telescopes and spacecrafts in space, it's a very important technological milestone for humanity.
Mass drivers and orbital elevators are common in fiction but I don't know what the scientific consensus is on the viability of such structures.
The Falcon 9 is ~500 tons of propellant for 25 tons to LEO. An A380 carries ~250 tons of fuel. In the Falcon 9 number the liquid oxygen is included. The RP-1 is a pretty much a cleaner diesel or jet fuel.
The cost is like $1500 to $2000 per ton so like $500 000 to $1 000 000 in fuel costs for a launch.
Fuel costs are still trivial compared to building and operating the rocket and is where huge reductions are possible.
Your argument is obviously wrong. If that were the case, all launch systems would have the same cost per kg, since they all are operating on the same planet with the same gravity.
But in fact, the minimum cost imposed by gravity (the energy needed to get into space) is incredibly low. The minimum fuel cost is a very small fraction of the cost of launching with current launch vehicles. The costs come from expendability and manufacturing and non-fuel operating costs. None of these are dictated by gravity.
There is a cost in mass. Rockets today are essentially a giant fuel tank with a few engines connected to one side and cargo connected to the other side.
Every kg of fuel is a kg of cargo you can’t launch. That’s the cost.
None of that justifies claiming the cost is due to gravity. The problem of getting to space is obviously affected by gravity, but the cost is dictated by other considerations. It's not like "oh well, gravity, we might as well give up because it's not possible to do much better."
Congressional mandates forcing NASA to use Space Shuttle components for the SLS that are de facto non-competitive, single-source requirements assuring contracts to existing Shuttle suppliers is contributing significantly to the costs.
For example, the NASA contract to Aerojet Rocketdyne to manufacture RS-25 engines is costing $146 million per engine. Each SLS launch will toss four of these engines in the ocean for a total cost $580 million. And that's just the engines of the core stage. For the cost of a single engine, they could have instead purchased an entire Falcon Heavy launch, which has two-thirds of the SLS lift capacity (and has to obey the same laws of physics as SLS).
SLS is the price NASA had to pay to get Congress off its back.
The more dollars and jobs you can claim you brought to your district during the next election, the better.
This isn't just a NASA thing, a NASA contract is probably pretty small compared to getting a new military base, or keeping one open that the military wants to close.
Because it benefits them (in kickbacks from contractors, for example) and because they can get away with it.
Having a well functioning space program? Doesn't benefit them much or at all.
Ultimately, it's because voters don't call them on their BS. If you've been a NASA fan, encouraging NASA funding regardless of what it's for, you're part of this problem.
> None of that justifies claiming the cost is due to gravity.
It scales a lot with gravity. Compare the cost of a vehicle capable of reaching lunar orbit (e.g. the Eagle), with the cost of getting humans into Earth orbit (e.g. the Mercury-Atlas). And the Eagle carried two people.
Sure, but once you're in space things can become easier, with high Isp engines and in situ propellant production. It's not necessarily all chemical rockets with fuel lifted from Earth.
Mostly because it's nice to have an uninhabited area downrange of the pad.
The benefit of launching from altitude would not be the potential energy, but the lower air pressure and density. The first would enable rocket engines to operate at higher expansion ratio, and the second would reduce aerodynamic forces. The benefit is apparently not large enough to justify the difficulty of operating on a mountain.
The goal of the rocket is to get the payload high enough to be in space AND fast enough to be in orbit. It's the later that takes most of the fuel, IIUC.
I can imagine two different answers to that and depending on which one you tend to think more there are two different answers to your question.
If you are thinking: space is high up therefore the higher we start the easier we will get there.
The problem with this is that getting into outer space is not that hard, staying there is the hard bit. The international space station orbits about 408km away from the surface of the earth. That is not a long distance. If you would have a car which can travel the same speed a car can usually travel but straight up you could reach that altitude in about 4 hour easy driving.
What is important is what would happen after you reach that elevation and turn off the engine of your car. If you have seen astronauts serenly drifting in space, you might expect that your imaginary car would do the same. But that is not what would happen. You would see that your car starts falling and rapidly!
In fact there is a word for such a flight path. It is called a suborbital space flight. Space flight because it went to space, but “sub” orbital because it lacked something to stay in orbit.
What is that something it lacked? Why do the astronauts float gracefully while your car plumets? The trick is that the astronauts plumet too! They are constantly falling back towards earth, they just go so fast sideways that the earth rolls out from under them. In fact that is what an orbit is. You are falling around the earth with a very high sideways speed.
In essence staying in space equals being in orbit which further equals going very fast.
So now you can see that being high is not the hard bit of staying in space. Flying as fast as a bullet is the hard bit, and of course starting from high won’t help with that.
But! You might think a different thing why launching from a high elevation might help. Maybe you already know that staying in space == going fast. So you are thinking: what hinders us from going fast? The drag of our atmosphere! If we would launch from high there would be less atmosphere around us, thus there would be less drag, thus we wouldn’t waste so much energy to fight it. And you would be right! If you could launch from a high elevation you could spare some energy because there the atmosphere is thinner. But when you run the numbers you see that this is a very small percentage of your total energy expenditure. Mostly because our rockets fly through the dense part of our atmosphere relatively quickly wasting only a little energy to fight drag. Launching from a high elevation would come with it’s own set of challenges of course and wouldn’t help that much relatively.
So depending on which thing you were thinking about you have an answer. Hope it explained the problem better. If you have any more questions about any of the details let me know and I will try my best to explain.
Also sorry for answering this long a seemingly simple question. Would love to answer shorter, but you know it is “rocket science”. ;)
> If you could launch from a high elevation you could spare some energy because there the atmosphere is thinner.
Reminds me of Eve on Kerbal Space Program. Gravity so high and atmosphere so thick that I had to use a helicopter contraption to lift the spacecraft to the highest possible altitude in order to get the rocket to even make it to space to say nothing of the absurd delta-V needed to actually inject into orbit.
My guys were stuck on that planet for a long time...
My thought was that the first mile up would be the hardest to get through because of being closest to the Earth's center. And isn't it something like 1% of the distance that they need to reach for "cheap" horizontal acceleration?
How is it wrong? Everything I've ever read about the subject says that because of the rocket equation you need massive amounts of fuel to lift up the fuel itself and the payload to get off the ground and into orbit. In order to burn that fuel, you need complex multistage rockets which require expensive materials and precision manufacturing.
Of course it's expensive. Surely if these things were built in space instead engineers would be able to build simpler, cheaper spacecrafts.
Rockets are not expensive because they use lots of fuel. Sit down and actually compute how much propellant is needed, and how much it costs. It's CHEAP, especially if you use LOX + hydrocarbons (as Falcon 9 and Heavy do).
The actual amount of energy needed to reach LEO is about the same as the amount of energy needed to send the same mass to New Zealand from the US by airliner.
The reason launch is expensive is because the launchers were thrown away. SpaceX radically reduced the cost by reusing the first stage multiple times. And there's more juice to be squeezed from that lemon, as the second stage is still being expended.
> The actual amount of energy needed to reach LEO is about the same as the amount of energy needed to send the same mass to New Zealand from the US by airliner.
Yeah but rockets use a lot more fuel mass compared to aircraft whose engines are airbreathing. Rocket engines need to carry their own oxygen in the fuel tanks and are less efficient as a result. Surely fuel costs are no trivial concern.
> The reason launch is expensive is because the launchers were thrown away.
Well I agree that it's stupid to just throw away the rockets into the ocean but I thought NASA just didn't have the capability to reuse them. A comment below says the US congress forced them to reuse old parts which makes no sense to me.
Are you blaming the cost on liquid oxygen? Sorry, but LOX is very cheap. It's the second cheapest industrial liquid, after water (or water containing cheap dissolved substances). The cost of the LOX is small compared to the cost of the fuel that it combusts with.
When people have looked at airbreathing launchers, they quickly discover that the designs optimize to 0% airbreathing, 100% rocket. LOX being so cheap and dense is a big part of that.
Indeed NASA doesn't have the means to reuse them, which makes it sad that NASA is being forced to play to their own incompetence in the SLS program. NASA originally wanted to get back to the moon with commercial launchers.
That's exactly pfdietz's complaint. NASA employs the same types of humans SpaceX does. If reusability was a design constraint they would have solved it like SpaceX did. But they didn't consider it a priority or even a goal to make regular moon travel feasible so they continue throwing away billions with such limited impact.
NASA was always a public works program, that's one of the reasons LBJ was its biggest high level booster back in the 1960s, it had an explicit mission to uplift the US South. Per the guy who invented the reentry vehicle, the lack of one or more staging space stations along the way for Apollo came from that spending "a billion dollars" more in Texas, call that $10 billion today.
After the end of the Apollo Project, "politics and corruption" were all that was left, as should be obvious from the lethally ridiculous design of the Space Shuttle.
> as should be obvious from the lethally ridiculous design of the Space Shuttle
Can you elaborate? Everyone here is calling it stupid but I don't really understand why. I thought it was retired due to expenses, NASA defunding or something like that.
As a general principle, the Space Shuttle program was massively capital constrained, so many trade-offs were made that compromised safety and operating expenses. I suppose the latter helped in limiting the number of flights, but then again half the fleet and their crews were lost.
Perhaps start with what killed two shuttles and their crews? Besides no provisions for escape unlike all other "capsule" based craft, solid rockets are _dangerous_ because you can't turn them off, whereas liquid fuel rockets will effectively turn themselves off in many disaster scenarios.
So for a get me out of here tower escape system a solid rocket makes a lot of sense, see also their use in ejection seats. But mounting some number of them (more than one unless used alone because you need symmetrical thrust) on the sides of your system means they must work perfectly every time.
The reentry heat shield protections which along with the wings etc. came from a requirement the Air Force says they never really wanted or needed, a single polar orbit mission returning to the launch location which thus required a lot of maneuvering in the atmosphere because the Earth turned while it was up there resulted in the infamously fragile tiles and some more refractory stuff for hotter locations (and eventually a bunch of tiles in a cooler location were replaced by something else).
Rear end heat shields are protected during the launch of a capsule, it's all hanging out there with the Shuttle. Change the foam and larger parts of it may break off, hit, and fatally compromise a part of the insulation system.
Now going from personal worry points and speculation:
The Space Shuttle Main Engines (SSMEs) are for institutional reasons extremely high performance and required a rebuild after every mission, so the SLS "throw away half a billion worth of engines every flight" would need to subtract that labor and parts.
That said, they were fired up and the SRBs not lit until it was clear the SSMEs were running fine, that resulted in three legit aborts and two from faulty sensors. Two failures after launch, split between both causes, noting catastrophic or mission endangering. But, still, you have all their complexity and SRBs.
It's a hell of a lot more complicated aerodynamic body/system than a cylindrical rocket and capsule system so that work was harder and more error prone. IBM Federal Systems modified a lot of code between the first and second launches, and caught an introduced error that would have released just one SRB. There's a 1984 CACM issue devoted to all this https://dl.acm.org/toc/cacm/1984/27/9 and is now free to read online or download, I highly recommend it. A lot of programmers outside of that world were concerned the code wouldn't be up to snuff, what you'll read in those articles explains how they pulled it off.
And, again, no escape systems. Fly enough times and things go wrong, the Shuttle compounded this by massively increasing complexity for very little gain.
Rocket books are written by scientists, not economists or MBAs. Elon Musk's major innovation with SpaceX was to look at it from a business & economic angle rather than the angle of scientists or millitary industrial complex which thrives on Cost Plus contracts.
It turns out fuel cost rarely exceeds 10% of the cost of launch even with the tyranny of rocket equation. Traditional expendable rockets (including SLS) essentially throw away 90% of the cost of each launch - hence the push by SpaceX to some of the fuel to try and land the first stage.
I initially thought rockets were not reusable because it was literally impossible to reuse them. I thought the launch and reentry damaged them beyond repair. Reentry modules require huge heat shields to protect the craft from being destroyed by atmospheric ablation. How is it possible for these things to launch into high altitudes and not only survive reentry but land safely?
It does sound kind of stupid to just let the engines and stages free fall into the ocean now that you mentioned it. I'm not sure how advanced Musk's rockets are but if they can land safely after being staged then that's an amazing innovation. Why isn't NASA all over this if it's so revolutionary?
They are currently reusing the first stage which is sub orbital - ie. Much slower, less re-entry forces. Still a major economic benefit for overall rocket cost. That said, Starship is planned to land from orbit & be reusable - let's see.
NASA is all over it from what I see - SpaceX has essentially captured virtually all of the commercial launch market and a good chunk of defence and science markets except for hyper specialized requirements or non-US defence launches.
I however don't see how NASA could have developed it given the politics involved with its funding essentially incentives Project thinking over Product thinking - I actually use that as an example when I contrast Project vs Product at work. SpaceX had to blow a couple of dozen rockets AFAIK to get to a stage where they land reliably - doubt NASA could have justified that to the US Congress. NASA's funding incentives encourage a risk averse approach to engineering ever since the very high profile failures in space shuttle and the early Mars missions. Witness how the Mars helicopter was rated for a low single digit of missions and has now completed a few dozens.
Spacecraft that require protection from re-entry are going far, far faster than first stages, so slowing them down using atmospheric friction creates a lot of heat. The Falcon first stage gets to about 8,000 kph and reaches over 100 km before it starts coming down, not high or fast enough to create the stresses an orbital re-rentry vehicle sees. The other key to reusability is having enough leftover fuel to land, control surfaces and restartable engines. Restartable engines weren't proven to work until the Gemini program in the mid-1960s, if I remember right; I'm sure the Saturn rockets was well into development by that time and the engineering costs to make major changes the lower stages were too great. Sometimes government gets set upon a course and it's very hard to redirect it; that's why innovators like Space-X are so valuable.
There were quite a few proposals for how to reuse rockets stages - actually you can see more the farther you go.
Certainly it could have been partially due to not yet having enough experience with many real world launches.
But at the same time a lot of the funding was comming from ICBM programs that don't really care for reuse by design & from army and a high profile space race with USSR. That kinda favored the expensive get-it-done fast expensive MVP instead of a more complex reusable solution that could be much cheaper in the long run.
And then the status quo took root & reusable rocket proponens were no longer taken seriously because - what were they thinkig, this is how we have always been doing it!
"And then the status quo took root & reusable rocket proponens were no longer taken seriously because - what were they thinkig, this is how we have always been doing it!"
Disagree as someone who as a kid watched this happen in real time. The Saturn V follow on was always planed to be reusable, with a huge first stage booster that was something of a bigger brother of the stage that would make it to orbit. NASA was starved for capital after Apollo and this resulted in the horribly deadly and very expensive to operate kludge of the eventual Space Shuttle.
Well it's technically correct. To get a 100kg object from the surface to a 100km Karman line needs about 30kWh of power. That's the same order of magnitude as travelling 100km sideways in an electric vehicle.
At 20c/kWh it would cost $100 to lift a 2 ton car and 4 occupants into space, or $100 each to get to the c. 400km altitude of the ISS.
Of course to stay in space requires far more energy as you also have to go sideways, fast. Very Fast.
But it's still pretty low. Sticking 1kg into Geostationary Orbit and keeping it there would take about 15kWh. A 2 ton vehicle with 4 passengers at 20c/kWh would be $1500 each.
Of course we lack a practical way of doing this other than with rockets, and thus enter the tyranny of the rocket equation. But the fuel cost is still far lower than the cost of the entire shuttle or apollo system, as shown by the efficiency of SpaceX -- fuel costs of $20/kg to LEO, or $1500 for a typical adult.
You're comparing rocket engines designed to operate in a vacuum to electric vehicles designed to operate on the ground. Rocket engines need a lot more fuel to generate that amount of power.
No, you're comparing the method of applying the energy required, which is painfully inefficient (rockets), to the energy actually required.
But I did touch on that in the last paragraph -- the energy required on a rocket to get into LEO is $20/kg, or $2k/person. It's a tiny amount of the total cost of launch.
Rocket engines are actually extraordinarily efficient. They're the most efficient heat engines we have. More than 90% of the thermal energy produced in the thrust chamber is converted to kinetic energy of the exhaust jet (especially in high expansion ratio engines). The fraction of chemical energy of the propellants of a launch vehicle that ends up in the kinetic energy of the final stage is surprisingly high (well, it was to me, initially.)
They are not efficient at doing their job (moving things upwards), hence we don't use them to get from the bottom of a skyscraper to the top. They have to carry their entire mass of fuel with them.
A large crane is far more efficient at lifting items.
But even if you accept you have to use a rocket, the cost of the fuel is trivial compared with the cost of launch.
Of course they are not efficient for that use case. That use case is not the same as the use case of getting to orbit. When the delta-V involved is similar to the exhaust velocity of the rocket the overall efficiency goes way up.
If you could vary the exhaust velocity of a rocket continuously, so it was equal to the total delta-V so far, the efficiency of converting jet kinetic energy to vehicle energy would be 100%, as the jet would be left stationary in the reference frame of the launcher. (This ignores gravitational potential energy and also that the mass ratio would diverge to infinity at zero velocity, but never mind that.) In practice, using a lower Isp first stage and a higher Isp upper stage partially implements this, and the overall efficiency isn't too bad.
That fraction is still larger than the economical utilization of space.
Think about how little propellant it takes to move products on Earth. And that's not even counting for the fact that transport vehicles on Earth runs a heavy percentage of its life time while a rocket does not do that. Even Falcons spend most of their time getting ready or recycled and not on an ascend or descend trajectory.
Any real trade will not happen at these gravity tax rates.
> That fraction is still larger than the economical utilization of space.
What does this sentence even MEAN? There are economical uses of space at today's launch costs. There would be even more such uses if launch costs were a few times the cost of propellant, as the cost of air travel is.
I get the feeling you are not thinking clearly on this subject.
If launch cost were few times the cost of propellant, what economic activities become feasible in space?
Sending tourists? Sure, tourists are already up there and it costs even less propellant to drop to the ocean floor but not many people/business seemed to be doing that. Maybe with the exception of oil platforms.
Speaking of which, what oil platform will be of space? Even a floating city in space that is purely afforded by the tourist spending generates no true economic value up there - all of it is being essentially propped up by the ground. What economic incentive are there?
The only way out is to manufacture IN SITU, sourcing from locally or gravitationally less burdensome locations, like the asteroid belt. It takes less deltaV to go to the asteroid belt from LEO than it takes to get to LEO from the ground.
Trust me I've been thinking about this plenty - though probably not to any use.
A tourism analogue could be Antarctica rather than the sea floor.
Antarctica is also an analogue for manned science. Reduce costs enough and it makes sense to put people in space rather than do things remotely. There's a base at the South Pole. The cost to get there would be similar to the cost of getting to LEO, in this few-times-propellant cost scenario. Yet no one talks about automating that base, it just doesn't pencil out.
Lower launch costs will enable much larger satellites to be built, with much larger apertures of antennas and optics, and with higher bandwidth, or with much less focus on expensive mass optimization. We could see satellites in high earth orbit being maintained manually.
At a few tens of dollars per kilogram, space disposal of nuclear waste starts to make sense.
I can recommend Terra Invicta as a very realistic grand strategy game demonstrating it nicely - you will never lift the thousands of tons needed for just a single ship in your fleet to protect the Mother Earth from aggressive extraterrestrial invasion.
But plop a few mining complexes (each couple dozen tons IIRC) on the Moon or near Earth asteroid and the tables turn quite quickly. As now you can build more station from extraterrestrial resources, which mine said resources and it goes from there. :-)
Isn't the true "ideal" a space elevator so you can continously deliver between the moon and the earth without having to burn lots of resources every single time?
Shouldn't that be what we optimize for in the long run? Its the only way I can think of that space cargo becomes economical. Then you can ship raw material up to the Moon and build from there, launch from there etc. and vice versa.
Maybe we'll see what Helium-3 can do for humans at that point
> Its the only way I can think of that space cargo becomes economical
Depends what you mean by economical, but a totally, rapidly reusable craft that takes mass to orbit would massively reduce the cost of getting mass to orbit. Not as inexpensive as a space elevator, but more achievable in the near term.
Sure but we aren't even close to a space elevator to get satellites in orbit, no known material could handle being the cable, it's probably a century or more off, if it ever happens, so for now we have rockets.
Yeah, a space elevator would be the most efficient way lift payloads to space where it's a lot easier to maneuver. Anyone knowledgeable about space elevators on HN? I wonder why it's never been attempted.
We do not have any known materials which are anywhere near strong enough on the macro scale for a space elevator on Earth. If we did, we would still need to launch it into space using conventional rockets in the first place, which would cost trillions of dollars at current launch prices and require solving a bunch of new issues (if it's launched in segments, how do you join them together at full strength in space? if it isn't, how do you coordinate ten thousand rockets to launch into orbit simultaneously - and where do you launch them all from?) Once it's in space, you have the issue that it necessarily will need to be above the equator, which every satellite in space crosses twice per orbit - and there's no good way to make a structure as large as a space elevator try to dodge things, so it also needs to be strong enough that it can handle impacts from space debris or derelict satellites at orbital velocities without weakening to the point that it breaks.
And then of course you need to supply power to anything climbing it - which is an immense amount of energy required to climb 30,000+ miles vertically - and there's no practical way of sending that energy up the cable itself (you could do it with superconductors, but the power requirements for cooling thirty thousand miles of superconducting cable is more than many nations consume). One option is to use microwaves to beam power to the climber, but this is currently only theoretical, and raises further materials science issues with the microwaves heating up the cable along its length.
Finally, having a space elevator is a massive hazard to the Earth in general. If most structures on Earth fail, the damage is limited to a small area where the structure stands. If a space elevator ever fails for any reason, it would wrap around the equator as it fell, releasing the equivalent of two Hiroshima bomb every mile along the equator as its kinetic energy is rapidly converted into heat. It's not quite as bad as the asteroid that wiped out the dinosaurs, but it would still be enough to significantly alter the climate and wipe out at least half a billion people from the impact alone. It's not a project that should be undertaken lightly.
I am not sure what assumptions you are making in your last paragraph, but I think you are off by enough orders of magnitude to assume you pulled those numbers out of thin air (at best)
> equivalent of two Hiroshima bomb every mile along the equator as its kinetic energy is rapidly converted into heat.
Little boy was 15 kilotons of TNT (63 TJ). Kinetic energy is 1/2 mv^2.
So you are claiming that the mass of a mile of the cable is such that mv^2 = 126e12 J
At equator the planet rotates at 463.8 m/s so you are assuming that the bottom mile of the cable weighs 585.5e6 kg? Ok, you're completely off base here.
Maybe let's look at a higher segment (at geosync orbit). Velocity there is 3.1e3 m/s. You are assuming a mile of that cable weighs 13e6kg. But on the way down it will both ablate (lowering mass) and slow down (lowering velocity), so you are assuming an even more insane higher number.
For comparison, a mile of one inch thick steel cable is ONLY 4e3 kg. Sure, space elevator needs something stronger, but even more so, lighter.
Yeah, you are just off by MANY orders of magnitude, and that claim was likely pulled out of nowhere
A space elevator needs to be far thicker than one inch at high altitude. Even assuming the absolute minimum diameter to safely lift a 2-ton capsule of about half an inch at the bottom (which means the cable will break when the first piece of space debris encounters it), any current material - the best currently available is Kevlar - needs to be about 800 feet wide at geostationary orbit before tapering down again. This would weigh about 130 million tons per mile. Of course, the cable tapers to the ends, so I averaged over the whole length to reach that figure.
Also, energy that goes into ablation doesn't just disappear - it dissipates into the atmosphere as heat, which means it contributes to the overall energy from the impact. And in falling it does not slow down, but rather speeds up - descending from geostationary orbit will accelerate something to about 10e3 m/s, further increasing the energy.
Air resistance is only a factor up to forty miles or so; most of that acceleration happens in the preceding twenty thousand miles. And again, air resistance just means more energy dissipation in the form of a blast wave.
There are currently insurmountable materials science limitations, and even the materials that come close are not currently possible to manufacture at scale, or even assemble (one carbon nanotubes does not necessarily have the same properties of many carbon nanotubes) at scale into structures which will withstand the structural stresses. I believe this is not necessarily true for other celestial objects besides the earth
For example, Pluto and Charon is a pair that sometimes comes up; a space elevator connecting Pluto to Charon would very possibly just about be within our current civilisation's capabilities, if for some reason we cared to build one enough to sink the Earth's economic output into it. They're tidally locked. (https://en.wikipedia.org/wiki/Space_elevator has its section on "Extraterrestrial elevators".)
Yeah I looked up the moon proposals and fundamentally they have to go to L1/L2 points and they are not stationary on the surface or have to pivot around the poles. A tether that was lunostationary is impossible since it would have to cut through the earth
The anchor point on the moon will be fixed. It's the counter weight at L1/L2 that will drift and will need some (small, according to Wikipedia) correction.
For what it's worth, I think you're right, although it's been a very long time since I did any mechanics. The tidal locking isn't completely perfect, so the elevator would probably have to be basically a spool of rope rather than an anchor; and the Moon's axis of rotation precesses every 18 years ish per https://en.wikipedia.org/wiki/Cassini%27s_laws, so again there would need to be quite a lot of flex in the elevator; but I don't see why it couldn't be done.
Ok downvotes but I looked it up on a not-necessarily-authoritative source it's estimated that a zylon cable would have a taper ratio of 13, with a mass of ~1k tons.
Earth space elevator is supposed to be grounded somewhere on equator, the orbital point is on the geostationary orbit and further away there is a counterbalance.
There are currently no plausible way to avoid collisions of such a structure with satellites which are below the geostationary orbit. Sooner or later each passive satellite will hit the elevator, and active satellites will have to actively avoid collisions for the whole time they are on the orbit. Any collision would likely disintegrate the satellite and bring serious damage to the elevator - easily enough to break the elevator; after all we're talking about colossal kinetic energy in collision.
Even if nanotubes would be used and could work by themselves - I'm optimistic on that - the inherent conflict between space elevator and the rest of cosmonautics currently is enough to prevent this idea from working.
Setting aside his BS, there's a chasm of difference between SpaceX and SLS: it's process.
SLS designs ONE (mostly) disposable ship, per year, max, taking a decade to integrate and realize. Epic Waterfall. They have several concurrent pipelines.
Meanwhile SpaceX designs a reusable ship factory. Scalable to as many a year as you can afford.
At the very least, Artemis is a functional space launch system with exceptional reliability and predictability despite its insane costs. The wasted billions are an embarrassment, but far less so now that we know a) the thing works, and works pretty darned well and b) it is, for now, the only game in town in its class.
Starship is an interesting project with a lot of ambitious goals, but it is far behind schedule in terms of development and the Raptors are suffering from a lot of issues that Merlins didn't have due to SpaceX's inexperience with cryogenic fuels.
So the question to be asked is: do we want an pricey but reliable and proven solution now, or do we hold out for years in the promise of some intangible futurist idea that will likely take far longer than anticipated to become a viable solution for crewed travel? If your answer is B, then it's fairly obvious you're less interested in the rapid progression of space travel writ large and more interested in ensuring a project you favor wins out.
In a perfect world, SLS would be a rapidly reusable rocket with 5 RS-25s, an inflatable heatshield, F-1 derived liquid boosters, and landing legs. But that's not the world we live in, and something > nothing, in my opinion. And I also find it important to put the price of SLS/Artemis in context to other far more wasteful government projects that produce no surplus economic value for people, like the F-35 program or the B-21 (questionable benefit over existing defense systems). In that context, SLS is almost utilitarian, providing valuable scientific jobs to engineers and scientists, while propelling the way to the Moon for this generation's astronauts and explorers.
Exceptional reliability? How can you possibly claim that? Reliability comes from working out all the unknown unknowns, and that comes only from experience.
Starship is not needed to condemn SLS. Falcon 9 and Falcon Heavy are sufficient to render SLS uncompetitive and unneeded.
In a perfect world, SLS would have had a stake driven through its corrupt programmatic heart years ago.
In a perfect (space policy) world, SLS wouldn't have had major components determined by the legislature. It's extremely expensive because that's what the legislature asked for, a single use rocket built using super expensive engines designed for a reusable rocket.
SLS scrubbed numerous launches for random failures. The final actual launch was performed only after a team of technicians worked on a problem in strict violation of safety procedures, waived for the occasion.
The only way to measure reliability is experience, and there has been exactly one (1) launch. It will take another 20 to get a good reliability figure, and we won't get that: we cannot afford to ever launch that many.
Weird take since NASA's Artemis page on landing humans on the Moon opens with a giant rendering of Starship on the Moon[1] and their plan[2] for getting to the Moon involves ~6-8 Starship launches plus orbital refueling against 1 SLS launch. So NASA's Artemis program leadership doesn't seem to assess that Starship is "some intangible futurist idea" that won't work anytime soon due to engines/fuel/etc.
The thing for me is that we (humanity that is) already know how to safely land a rocket booster and reuse it. SLS has been in development for quite a while, and lots of funding. So why aren't recovering the boosters part of the program? The most likely answer is that no one on the funding / direction side thought it was worth while, or possible, at a time when that could be engineered into the system. The cynic in me feels that there is more profit to be made in throwing away the boosters. I wonder if the true answer is somewhere in between?
The purpose of SLS was to funnel money to particular contractors and facilities. It's not just that there's more money to be made by inefficiency; it's that the entire purpose of SLS is inefficiency. That it might achieve anything in space is entirely beside the point.
SLS was also even further behind in development that Starship is... it was supposed to fly before Falcon Heavy. Also the next SLS flight isn't now, but more like 2 years from now... Starship might very well by flying by then(it better be given that NASA plans to use it as the lander).
Not sure where you got the idea F-35/B-21 are questionable benefit over existing systems from(we don't know enough about B-21 to say this, and F-35 seems to have proven itself by now).
Mercury through Apollo really did not like the idea of using solid rocket boosters, you can't turn them off if things get out of hand, and of course they'll do that themselves in lots of failure modes. Suitable for a launch escape system ... and see the Shuttle for when these principles were turned on their head.
Its SRBs, now being literally recycled for Artemis were low capital, high operating cost kludges that infamous killed one shuttle and its crew. In part because there was no provision made for escape aside from the pilots in the first couple of launches or so and that was rather limited, SR-71 technology with a pretty low max altitude.
On the other hand the Orion crew capsule does have a tower escape system.
So that old NASA you decry, they didn't lose a crew except on the ground due to a high pressure test with pure oxygen!?!?!! OK, that's a credible validation of that part of your thesis, see also Apollo 13 which was a close call.
On the other hand does the Orion have a heavy shield for the astronauts to shelter behind in case of a solar storm (see Heinlein's Podkayne of Mars)? If not Apollo and the Artemis program are every bit as dangerous in what was a primary reason Nixon stopped Apollo before all its planned missions, program delays would have extended it into the change in the solar cycle.
I would also note the start of this program many years ago was so badly designed the booster system's vibrations would have been lethal to humans. Springs in the crew capsule were part of the proposed solution to that, but going back to Shuttle diameter SRBs, only adding one segment, and all the mass of the tank and SSMEs should have fixed that. If my memory is correct that was a rocket powered by a single stack of SRBs, purely for sending crews out into space.
But I'd like to know what happened after the Shuttle and it to make NASA take crew safety seriously. NASA was utterly callous about the known risk from the launch that killed the second shuttle and its crew.
I finish by noting a bit of humility is warranted after just a single test mission success. That NASA and its contractors were able to pull it off is quite a feat, but as the Shuttle should have taught us bad designs can eventually catch up with you.
It blew my mind to find out the first crewed mission to launch on the Saturn V (Apollo 8) flew all the way out and around the moon. No low earth orbit shakedown or anything, just straight to the moon (without landing). A few more launches tested they could dock with the LM and then Apollo 11 just went for it back to the moon and landing. The pace they went at is pretty unbelievable today.
I believe Apollo 8 was originally supposed to be a low earth orbit shakedown with the LEM. Because the LEM wasn’t ready, they decided to send them to the moon.
I have to dispute that doing it more safely is a worthwhile goal for SLS.
It's useful to think about safety issues in terms of the statistical value of a human life. This is how much one should be willing to spend to save one expected life. It's a vital number for planning purposes. For example, should we install a guard rail at this corner? Is controlling this release of this chemical justifiable? Compute if the cost is less than the expected value of lives saved. If so, spend the money, if not, don't.
The usual statistical value of a human life is around $10M. And you immediately see the problem: a rocket that costs $1B to launch is, in effect, killing 100 statistical people just by being launched. If the result of the launch is valuable enough to justify that mathematical carnage, wouldn't it also justify subjecting the astronauts to real risk? Conversely, if it's worth delaying a launch to reduce the risk to astronauts, is the launch really worth having spent all that money on at all?
The space program has been caught in an internal contradiction, where the purported benefits are claimed to justify large expenditures, but not claimed to justify risking astronauts. And this makes no sense.
To actually justify reducing astronaut risks, launch and mission costs must first be greatly reduced.
Except this math doesn't always work. 40k people die in the US in car crashes and nobody really cares. One idiot tried to smuggle something onto a plane in his shoe a couple of decades ago (didn't even kill anybody), and now for all these decades 1.5 million people _per day_ must spend countless hours in lines to take their shoes off.
I don't think the usual statistical value applies to an astronaut, especially an astronaut on a mission.
At least, the loss to NASA will be much more. For one, they're going to spend a ton of money on investigagions. For another, it could significantly impact their future budget, and their ability to hire. It would depend on the details of the deadly incident though.
Ah, so astronauts are inherently much more valuable than your average citizen?
Our course is clear! We must design launchers as cheaply as possible, to launch as many people into space as possible, to transmute them from relatively worthless disposable units into valuable astronaut heroes. Even if 10% of them die (say) the net increase in their overall value will make the effort totally worth it. They don't even have to do anything up there; just being an astronaut is inherently valuable, I am being told.
Would people want to drive cars built by people with this mindset, on roads designed by people with this mindset, to get to airports to fly in aircraft built and regulated by people with this mindset?
Trick question! Almost everyone does and doesn't see anything wrong with it.
I would not want to get into an expensive risky rocket, since I don't see the benefit that would be commensurate with the enormous cost. If the cost were radically reduced, I might try it, and in that very much cheaper rocket the safety level would be much higher (or else the actual cost, including risk x value of my life, would swamp the ticket price.)
NASA really doesn't do a great job at getting people excited about these missions.
This was such a perfect opportunity to include anything to make the trip more accessible to general audiences. High quality Video footage? VR capture? The NASA feeds have been long low-quality videos.
Well the official video stream was quite lackluster, with NSF or Everyday Astronaut streams being IMHO better, not to mention some of their beautiful recorded footage.
But the in flight pictures and videos afterwards were pretty nice! :-)
I didn’t know what a Baja California was until I moved to California. Seems like an honest mistake. Would have been helpful if they said “en route to San diego” afterwards
Clearly all the people complaining have never made a typo in their lives, and are unable to deal with the horrible inconvenience of having to actually deal with one!
right, it's a typo, it doesn't matter, and there was already a reply 4 hours before yours that said as much, so i'm not sure what you were aiming to contribute with the reply that doesn't acknowledge that it is a typo
To be honest I didn't even seen the typo, and I genuinely thought the person was suggesting that NASA was unaware Baja California is not the US, or that somehow a US spacecraft would land anywhere other than the US.
And now we wait two years for another “iterative” launch. No wonder it takes NASA 20 years to do anything. And what are they doing in those two years? Certifying the flight computers. I was fearful SpaceX was falling behind but now I see that this was just a publicity stunt to make NASA look competent and effective. When they aren’t.
Awesome! However, "Our spacecraft is home" is a stretch. A small portion has returned, but we taxpayers paid for the whole thing. If I had returned home with the same percentage of my parents' vehicle when I was a teenager, there would have been hell to pay.
1. They don't need life support that amount to 2000% active mass. Maybe 20% since we can still count solar panel as their life support.
2. They are far far far more sophisticated than what they used to be. Especially with modern processors. We can even embed some level of AI decision making onto these robots so they don't need to call back home for every decision.
3. They are far cheaper and can tolerate far lower safety margin. We can potentially even mass produce them and launch 50 at a time.
Imagine if we're just throwing a bunch of rovers on moon and each of them are capable of suicide burn and landing themselves. Maybe 2/10 will fail but we still get 8 rovers that can just roam the moon for fun.
A man with a shovel can do in an hour what a moon-grade robot can do in a day, with some luck. (Two months on Mars.) Give the man a moon digger, a moon bulldozer and a mooncrete production facility (with mooncrete mixer trucks) and see what he can do then ;)
“If scientific knowledge was all we were after, then the Federation would have built a fleet of probes, not starships. Exploration is about seeing things with your own eyes.”
— Captain Kathryn Janeway, One Small Step, Star Trek Voyager Season 6, Episode 8
Your own eyes uses many neurons to transport the images to your brain where it is processed.
Neurons may be hacked so blind persons can see through a device.
The abstraction is more easily done by placing a screen in front of the eye so no invasive surgery is needed while images from far away cameras can be presented to the brain.
Disclaimer: I don't believe in metaverse and do not work for meta.
I work in a robotics research group. My natural bias is to always praise the robots.
If the goal is just to have N robots/rovers on the moon for fun/data collection, then we don't need to send humans to space.
If the goal is to bootstrap a profitable space/Moon industrial complex, then we will need a lot of robots (some autonomous and some remote controlled from Earth) and a number of humans in the center of events. Humans are critical for keeping automation working and for adjusting to unforeseen circumstances.
If the goal is a profitable space industrial complex somewhere other than Earth, than humans probably need to be there, but that seems like way way ahead of what we're thinking of.
We're not even close to bootstraping a cluster of autonomous robots on the moon, taking over the basic functions of base operations. Any humans at current stage is basically on sightseeing duty.
> We're not even close to bootstraping a cluster of autonomous robots on the moon, taking over the basic functions of base operations. Any humans at current stage is basically on sightseeing duty.
That's not really fair to say that people are there just to observe. For instance, Apollo folks took a lot more of geological samples that Lunokhods did and from a larger variety of places. The difference in mass was about 1000x (almost a ton vs almost a kg), geographical coverage was about 1000x and getting to different features was immensely easier for humans.
It might be hard to believe, but for space projects bigger than some scale using people is actually cheaper than sending robots.
The big reason for that is that the robots are very modest in their overall capabilities. With humans, you can't get cheaper than the cost of sending one, or better few, people, but when you cross that line, you suddenly have a lot of functionality for free.
I agree. People underestimate the scientific abilities and flexibility of a highly trained technician, particularly on solid planets and moons.
A human living on Mars could operate multiple geographic exploration rovers at much higher speeds than currently (existing rovers get 0.1mph max). This is the benefit of having a 60ms ping time instead of 6-20 minutes. Plus the ability to troubleshoot, clean off solar panels, run slightly different analyses without needing to build it into the probe 8 years ago, assemble sensor stations, etc.
Yes the mass budgets for manned missions are titanic. But with even half-way good mission planning we can get more science done than the equivalent mass of robots - at least for Mars and the Moon. Food and life support mass for long trips to the outer planets (or shielding for Mercury) mean robots will win there.
NASA's total budget is approximately one half of one percent (0.5%) of the federal budget. Even at its peak in the 1960s, it never reached 5%. Seems pretty reasonable.
Since you think it's so reasonable, would you please pay my share? If distributed equally among the US population, it is about $75 a year per person, which of course comes out to about $6.25 a month.
Now here comes a completely unreasonable (maybe not) idea: Democratized budget.
Every year tax payers specify where their tax money goes. 50% of their taxes will go directly where they decreed it be. The other 50% and any debt can be allocated by the congress.
There should also be options of "Let congress handle it" and "whatever the previous years makeup was" and options to adjust from there.
NASA will probably be better funded, by a huge margin.
At what cost though? What programs would suffer funding decreases?
This is why we elect representatives. It’s not a perfect system but the average citizen would not have the context necessary to make direct decisions on it.
I like this approach. If we divide the federal budget into sufficiently small chunks, all the spending is reasonable, and we don't have to worry about deficits and such. Utterly brilliant reasoning!
Now that Orion has returned safely to Earth, it feels so amazing to talk about Artemis I as the past! If its help in returning humans to our Moon deeply moved you too, you can follow the pieces of its progress via my one-of-a-kind, technical newsletter called Moon Monday: https://blog.jatan.space/s/moon-monday
It also covers global lunar exploration, science and commercial developments to show that our return to the Moon this is truly a worldwide trend and how valuable each vertical is.
People keep asking why this is a big deal- we did this fifty years ago, right? It should be a lot easier now with modern tech.
Yes, but now we're doing it safely. The Apollo program took risks that today's NASA never would allow. We're better at that now, but it's a lot more work.