It's the whole architecture: a two-stage, rapidly reusable rocket with as much cargo capacity as anything to ever fly. And just as important for interplanetary flight: The upper stage is refuelable and is integrated with the passenger compartment and has a large delta-v capability as well as aerobraking/capture/entry.

It really breaks basically every human spaceflight architecture. It's a two element architecture (with common propulsion, simplifying development for the booster) that accomplishes every goal of virtually every other interplanetary human spaceflight architecture conceived. This simple architecture (while avoiding the huge penalties of single-stage vehicles) means that it can be developed extremely cheaply.

It really is a gamechanger in spaceflight. All of spaceflight.

400 satellites per launch? For maybe an incremental price of about $40 million near-term and $4 million long-term? That's, um, $10,000 per satellite. That breaks every model of space development.

And it's not like all of this was unforeseeable. Even Werner Von Braun proposed refueling-dependent human spaceflight architectures in the 1940s (in his fictional book about exploring Mars) that would enable low cost. But for historical reasons, human spaceflight took another path.

yeah, you're absolutely correct. It's the whole package. I want to know what went so right at SpaceX though.

from wikipedia "In late 2001, Mueller began developing a liquid-fueled rocket engine in his garage and later moved his project to a friend's warehouse in 2002.[1] His design was the largest amateur liquid-fuel rocket engine, weighing 80 lb (36 kg) and producing 13,000 lbf (58 kN) of thrust.[1] His work caught the attention of Elon Musk, PayPal co-founder and CEO of Tesla Motors, and in 2002 Mueller joined Musk as a founding employee of SpaceX."

that's a hell of a lucky find by Musk and a hell of a roll of the dice by Mueller. Around the same time is when Shotwell joined, she's equally incredible but in a different way. i don't now how Musk found her.

Even then, what followed has been black swan territory. Every major development announcement at SpaceX is met with "you're crazy" and laughter from the industry and yet, a few years down the road, there it is working. Again, i really want to know what went so right.

Just to add a bit of clarification: When Mueller was making rocket engines in his garage, he wasn't some random nobody. He was definitely the most accomplished and successful rocket engine designer outside Russia, and could make real claims about being the best still working engine designer on the planet.

The reason he was tinkering on small engines in his garage instead of designing big engines for his employer, TRW, was that after designing the best American first stage engines (the TR-106 and TR-107), it became clear that it didn't matter that his engines were better, for political reasons it was impossible to kill the RS-25 program (also known as SSME, or Space Shuttle Main Engine), and therefore any future vehicle would use them instead, despite them being strictly worse for any use other than for the Space Shuttle. This was immensely demoralizing to him, and he was considering just quitting the industry and doing rockets as his hobby. Then Musk managed to convince him to work at SpaceX, for a much lower wage (and stock options, but the rational early valuation for rocket company stock is $0), mostly on the promise that at SpaceX, his engines would actually fly.

The NASA program of record heavy lifter, SLS, is still using the designed-in-70's RS-25 now, 25 years later, and plans to toss 4 of the $40M engines into the ocean on every flight. SpaceX is what happens when you build rockets with actually modern technology, instead of all the components NASA is forced to use because some senator needed to maintain employment in his home district.

Not only is the RS-25 old, but it's several times more expensive per unit thrust than the Saturn V's engines. That was worthwhile for the Shuttle because they reused the engines. Naturally, NASA and its cost-plus contractors decided the RS-25 was the perfect engine for a disposable rocket.

> NASA and its cost-plus contractors decided the RS-25 was the perfect engine for a disposable rocket

NASA did no such thing. They were ordered to use the engine by the Senate.

(When the Constellation program was canceled and the SLS program was created, Senate ordered NASA to pick solutions that "minimize contract cancellation costs". Not minimize total costs, minimize costs related to cancelling contracts. This of course means that the contractors you are already using can offer any solution they want, at any price they want, and so long as they are willing to waive the contract cancellation penalties as part of their package, you have to pick that solution.

They all offered a really expensive, really bad deal. I know several NASA engineers who quit in disgust because of this.)

Thanks, I wasn't aware of that but it's not surprising.

The path taken in the 1950s for spaceflight was dictated by its funding source -- missile development. Missiles were optimized for high performance and were single use devices.

Even when dedicated non-military rockets began to appear, e.g. the Ariane range and the Space Shuttle, they had dependencies on legacy infrastructure that was originally designed for strategic weapons (i.e. it was intended to work at peak performance, just once). The payloads evolved to reflect the launch system constraints, so very expensive, one-of-a-kind comsats and earth resources satellites, each of them a bespoke design (or at most one of a dozen or so).

SpaceX isn't building missiles; it's optimizing for reliability and cost (which means reusability). More like airliners than missiles. This doesn't mean low performance (the efficiency and power density of a modern civil airliner turbofan would have been a jaw-dropper to 1940s military aviation engineers) but it does mean the performance goals are different.

I am still extremely skeptical that Heavy/Starship will facilitate a Mars colony ... but that's because I'm skeptical about the economics and practicalities of building an off-planet colony when the externalities we normally take for granted (like a compatible biosphere) aren't available and nobody's really done the necessary R&D work on self-contained biospheres -- even the ISS is effectively an open-loop system dependent on constant resupply. (Biology and ecology are much harder than they look to a naive outsider.)

Riffing off of your comment:

Neal Stephenson has a pretty good article about path dependence in space exploration: https://slate.com/technology/2011/02/space-stasis-what-the-s...

I have the same doubts. I think it'll inevitably happen, eventually, but the timeline may be wayyy longer than people seem to think.

I wouldn't be surprised to see a small settlement for research or something in my lifetime. Maybe something like what we have in Antarctica.

We really, really need a second run at Biosphere 2, only this time integrating what the failures of the first run taught us. (Only 25 years ago, with no serious follow-up!)

The next step would then be something like a Bigelow B330 module in LEO, which is close enough to get the astronauts home from in a hurry if something goes badly wrong.

(These steps can be commenced with current tech: Heavy/Starship not required.)

Step 3 would be a bigger test hab out beyond the Van Allen belts, preferably a couple of habs revolving around a hub to provide centrifugal "gravity" at Lunar or Martian levels. Goal is to test systems for use on planetary surfaces exposed to cosmic/solar radiation (because outside our atmosphere). Starship is probably mandatory for this phase, because it's a lot more massive and a lot further away. Alternatively: conduct this experiment on the Lunar surface, once astronaut return capability is available (but why waste expensive reaction mass if you can simulate a gravity well?)

Without a lot of R&D work under these conditions, a closed-circuit life support system for Mars is a huge safety risk for the astronauts who set it up (and who are too far away to rush home in a hurry if it goes badly).

And without closed-loop life support, a Mars "colony" is no more a colony than an Antarctic research station reliant on resupply for everything except air and water.

What went right, the way Elon, explained, was that they are a private company that isn't set up to profit from long term government counteracts. For them, it's sink or swim. So they swim. He explained that others are set up to take a long time because they never want the contracts to run out, to keep getting money.

Also his system strategy is : the best design to use is one that doesn't require the design in the first place. Ie get rid of many systems. Keep it simple. Less can go wrong, and the schedule is reduced. "Tight is right. Long is wrong". He did a great talk last month.

You guys might like a video I'm releasing on Halloween, "the actual, physical, reason why time slows at the speed of light". My channel is "TheRainHarvester". Stay tuned...

There's a popular saying "rocket science is not rocket science". There could be other people, instead of Mueller or Shotwell, which could do similarly well. SpaceX is just a first company which succeeded - not that nobody's tried; at some point that was bound to happen.

It's almost like there's an insanely talented genius at the top making consistently great decisions!

>It's the whole architecture: a two-stage, rapidly reusable rocket with as much cargo capacity as anything to ever fly. And just as important for interplanetary flight: The upper stage is refuelable and is integrated with the passenger compartment and has a large delta-v capability as well as aerobraking/capture/entry.

I don't know much about SpaceX, but I do follow Tesla closely: how much of this is reality versus "things we'd like to be able to do in the future"?

What do you mean by "reality"? With SpaceX critics are often in a state of "you're currently here" on the list of steady achievements. In general, SpaceX delivers most of important Musk promises (just doesn't do it as soon as promised), so - Starship is technically possible to build and run. In the future. Like, in 5 years from now.

>What do you mean by "reality"?

For example: is the rocket really "rapidly reusable"? Or is it theoretically "rapidly reusable"?

In the same way that all Tesla's sold since 2017 have the hardware capable of self-driving. Are they really capable of it, or theoretically capable? Until you have self-driving software or have rapidly reused the rocket, how do you know? In the same sense, until they landed a rocket, saying "we have a rocket capable of landing" didn't matter; landing it did.

I may not be articulating it properly, or perhaps I'm misunderstanding how they test these claims.

Discussing this aspect, I'm still not sure what's the difference between really and theoretically.

We assume Falcon-9 first stages are really reusable, right? Not that they are claimed to be reusable, or they are theoretically reusable, but really reusable.

Then the question is, what is the criteria to be really reusable? Would only direct demonstration be enough? Then of course Starship isn't real. If there are other ways to claim real reusability, then maybe Elon's plans are real(istic). Also, historically, Elon claimed something for SpaceX before which later became real.

There aren't currently proofs that Starship isn't possible to create (with parameters similar to stated).

They are building three (or is it four?) full size flight prototypes right now.

I had the same question/concern... Until I saw the rockets landing!!!

I just hope it doesn't turn out there isn't that much useful to do in space.

The killer app of spaceflight is telecommunications, and it's a trillion-dollar market. There's nothing else in the next, well, half a century that would provide a market of that order of magnitude (with the possible except of space-based solar power, but that has many of the same drawbacks as nuclear fission).

I think we might just do stuff in space because we WANT to do it. Stuff like space tourism, etc.

There's also potential for asteroid mining, building space/lunar colonies. Not to mention Musk's dream to build a Mars colony. Plenty of "wow" factor for space exploration, imo.

All those are either unprofitable or have much lower than trillion dollar revenue possibility in the next 50 years.

To take asteroid mining as an example: The entire platinum group metal market on Earth is only about $10-20 billion per year. Adding a huge supply is likely to crash the market price well before you drive demand up high enough to compensate for the far lower price. So platinum-group metal mining is not huge.

Mining water is also a very small market. You're primarily replacing rocket propellant for launch vehicles or maneuvering, but this is a small market. The entire commercial launch market is about $3 billion per year in revenue. Adding non-commercial launch may more than double it, but you're still talking less than $10 billion per year. And propellant (or propellant services) is going to be a small part of that. It won't help get payloads to LEO, so you're left with just providing services from LEO to GEO or something like that. Maybe for deep space missions... But even that market is very small. NASA makes up the majority of world funding for deep space exploration, about $10 billion per year optimistically. Propellant is a small fraction of that.

So for water propellant, we're looking at maybe $100 million to $1 billion per year in revenue.

For structural materials, the market is even more speculative and less proven.

Space settlements are going to be small revenue, too, for the foreseeable future. NASA human spaceflight, philanthropic, and space tourism are really the only consistent funding sources there. The settlers themselves won't be super rich as they'll need to be sustaining themselves, but let's just say we have 10,000 settlers each able to spend $100,000 for your services per year. That's just $1 billion per year. To get truly sizable, you need like a million people living in space, and it's still only $100 billion per year.

So it's primarily telecom that is the big space market. The others are much smaller and less profitable. It turns out that serving billions of Earthling consumers is where the real money is in space.

EDIT:

There are 3 big (trillion dollar) markets:

1) telecomm

2) energy

3) high speed transport (aviation)

Space can in principle address all three. The first one is the only real "slam dunk," the other two are questionable to one degree or another. SpaceX is pursuing 1 and 3.

I disagree with your statement on asteroid mining.

The profitability of mining asteroids doesn't come from bringing the metals back to earth and selling them on the traditional market: It represents the ability for spacefaring communities to build their own ships for a much lower cost than building and launching terrestrial rockets on Earth.

Furthermore - Space Stations, orbital manufacturing plants, multi-generation starships, solar arrays - all of these become incredibly cost effective when the metals used to make them become hypersaturated from asteroid mining. It's a means to an end, but by no means is it without value.

I think 1) and 3) are the only ones that do not require advances in fundamental science to achieve.

Space based energy requires a way to send the energy to the surface for monetization. The three ways to do this would be 1) Wireless transmission -- infeasible with current level tech at the distances required. 2) Wired transmission -- requires materials with very high tensile strength in quantities never before produced. 3) Deorbit batteries -- You spend more energy launching/deorbiting and distributing batteries than you gain.

High speed transport (ground to orbit, and interplanetary) have huge problems in scaling, but it mostly can be solved with current level engineering.

Wireless transmission is perfectly feasible with current tech level and distances required. In fact, we do precisely the same thing with telecommunications.

It's just a difference in scale. To get high efficiency, low cost radio amplifiers, you need to operate at relatively low frequency (think microwave oven magnetron, but modified to follow a phase and frequency input). Rectification of this has also been done. But you're going to need an enormous aperture on both sides to make it happen. That means, to me, you need on the order of 10 Gigawatts to be feasible (rough, back-of-envelope calculations). And even then, you need an enormous plot of land, preferably in the desert. So you're basically competing with cheap solar power backed by cheap batteries. Both of those are improving in cost every year. So it's possible. Feasible, even, if we had no other options. But it's not going to be competitive from what I can tell.

So it's the same type of scaling problem as #3. Except the main issue with #3 is safety: passenger aviation is just so ridiculously safe it's extremely hard to compete with.

If it's just one company doing the mining, there's no reason to crash the market. Hold 100x the world's annual demand for platinum and sell off 1% per year for 100 years. 20 Billion times 100 years isn't so bad.

I think demand for these metals is relatively inelastic, so even supplying a relatively small amount may crash the market. If you double the supply of platinum per year, you will crash the market price.

If you have that large of a stock, you could corner the market. Undercut the competition slowly, until they all go bust. Once the mining infrastructure is left in ruin, raise prices to whatever you want. It will take a while for the competition to re-mobilize the infrastructure to compete.

Not the most ethical business plan, mind you....

Platinum is a very useful catalyst. If it were much cheaper, we could do more with it.

Aluminum was a precious metal for a few decades. Royalty used it for their best forks and spoons. Now we make airliners out of it and the aluminum producers are doing just fine.

It's unlikely we'll be making airplanes out of platinum (terrible strength to weight ratio), and it's unlikely catalysts will consume as much as is used for structural applications (the global market for catalysts is itself limited, and it's not like we're going to be using orders of magnitude more catalysts of all types if the price of platinum reduces). Even still, the worldwide market for primary aluminum production is just $100 billion per year. And aluminum is a common ore. Even in space, platinum is rare.

Space mining is made out to be the pie-in-the-sky paydirt of space dreams, but it's still a much smaller market than telecoms.

Not only fuel! It would be a big boon if bateries (think Edison or lead battery not Li-ion), construction beams, antennas, heat radiators and similar heavy low-tech items can be manufactured in-space from asteroid ores so they don't need to be launched. With thousands of satellites, there will certainly be big market for such parts. Precious metals will be only a byproduct in the beginning.

Useful things to do in space:

1. make more space habitats

2. live

3. breed

4. astronomy

A friend of mine was one of the metallurgists who worked on raptor. It wasn’t like that... They went through dozens or hundreds of incremental improvements over years with lots of time in the lab looking for micro fractures and other issues after every revision. In typical SpaceX style, the team was working 70+ hour weeks in burnout mode and my friend promptly quit after the alloy was “done”. She seems much happier now.

thank you for that, the only info. i have is from articles and PR. I love seeing what SpaceX does, and maybe they couldn't do these things otherwise, but stories like yours mean i would likely pass on an opportunity to join the company. It's not for me.

FWIW, a lot of people join SpaceX (and Tesla) for 2-3 years to work on cool stuff, get the experience, vest some options, then move to other aerospace companies with much better work-life balance. It attracts a lot of smart people fresh out of school and people who are passionate about spaceflight, it's just not a place to work if you value time outside of work or a low-stress job.

The Raptor engine is an even bigger deal because it actually flew. Still not ready, but it is well past the "paper rocket" stage.

Once we get this lifting capacity, to me the big win is that we can build and launch Orion ships on the moon. None of the fallout risk if launched from there, or rockets can lift the ship out of the gravity well of the earth.

Once you have orions, you can move a lot of heavy stuff quickly around the solar system. Orions can probably go interstellar if we fire off fuel pellets for them to catch up to, or can somehow doe antimatter catalyzed fission/fusion.

Once you have that lifting capacity, Orion drives are probably a bad idea.

Orion drives are great if you just consider performance, but not cost. It gets it's great ISP and thrust at the cost of being very inefficient in it's use of fissiles. If you can lift propellant into orbit at the cost SpaceX is projecting, for any in-system work it is more economical to use much less flashy nuclear thermal rockets with much worse ISP, because the propellant is cheaper than the fissiles.

And if you are willing to throw out the fissiles, why not a Nuclear Salt Water Rocket? [0] (warning: engineering realities may make this impossible) (one of a very short list of possibilities for a buildable-within-a-century torchship)

Other downsides include "using it for take-offs will leave a large crater that will glow blue for several hundred million years, as will everything downwind in the fallout area", but who really cares about takeoff areas? (That's for the silly plebs left behind on the ground to worry about - you're headed to SPACE!)

0: http://www.projectrho.com/public_html/rocket/enginelist2.php...

Would you need to launch them from the Moon? Why not build and launch from space?

Tell me more.

"So, SpaceX developed their own superalloy in house that they named SX500. According to Elon, it’s capable of over 800 bar of hot oxygen-rich gas. That may have been one of the biggest hurdles in developing the Raptor engine."

almost halfway down, the article is long but so well worth the time. https://everydayastronaut.com/raptor-engine/

The reason "over 800 bar of hot oxygen-rich gas" is a high hurdle to break is the propensity for a metal to rust and become useless is proportional to the pressure (concentration) of the oxidizer (oxygen) it's surrounded in and how hot it is. So this metal is able to withstand 800 bar (1 bar ~=1 atmosphere), or 4 thousand times as much oxygen as sea level, at quite elevated temperatures. This is a hellish environment to not just immediately combust in.

And note that at 800 bars of hot oxygen, metal doesn't so much rust as it burns with a bright flame. The environment in the Raptor oxy-rich preburner is much worse than the typical oxyacetylene torch that is used to cut steel.