Personal example buying a used car with 60k miles that had some idle/start issues at times but generally ran well. Everything seemed to be serviced in a timely manner but the spark plugs were still the originals. Those spark plugs have a generous "100,000 mile" service interval. I pulled the originals and sure enough they weren't in the greatest shape. $40 later I never had start/idle issues again for the remaining time I owned the car.
If rockets became as common as cars, what kind of accidents would we see? And would insurers insure them?
Ultimately I "gave up" and just bought a 981 Boxster S (a 2013) for $42k. A 986 Boxster from the same era as an S2000 would absolutely be S2k prices.
I owned a Miata and wanted to own an S2k before moving up to the Boxster, but for today's asking prices, it just didn't make sense.
would be a fun publicity stunt.
Falcon 9 433k kg
Atlas V 547k kg
Starship 1,200k kg
Starship Booster 3,600k kgThe nuclear industry was using metric weights fully when I did my apprenticeship in it in the late 1980s. Good job really as I think a conversion error could be catastrophic.
Same goes for gallons though, US gallon is smaller than a UK one.
European colleagues regularly go, "what other kind of tonnes are there?" and we get to share the joke of how silly Americans are for still using imperial tonnes.
At a scale of 433 tons, it doesn’t really matter much which kind of tons (unless you’re actually doing the rocket science, of course).
https://en.wikipedia.org/wiki/Orders_of_magnitude_(mass)
The table at right is based on the kilogram (kg), the base unit of mass in the International System of Units (SI). The kilogram is the only standard unit to include an SI prefix (kilo-) as part of its name. The gram (10−3 kg) is an SI derived unit of mass. However, the names of all SI mass units are based on gram, rather than on kilogram; thus 103 kg is a megagram (106 g), not a kilokilogram.
The tonne (t) is an SI-compatible unit of mass equal to a megagram (Mg), or 10^3 kg. The unit is in common use for masses above about 10^3 kg and is often used with SI prefixes. For example, a gigagram (Gg) or 10^9 g is 10^3 tonnes, commonly called a kilotonne.
One context where I have seen this used is carbon stocks, e.g. petagram of carbon (PgC):
https://www.pmel.noaa.gov/co2/story/Carbon+Cycle
Of course Gigatonne of Co2 is also found very frequently.
Really, what SpaceX did was radically different from the tests in the 90s from the rockets, to the controls, to the reusability goals. Otherwise they wouldn't have built Grasshopper.
Now NewGlen is kinda a knockoff of Delta Clipper, but that's a different beast.
That's a huge engineering difference, roughly like the difference between a car and a helicopter. The Falcon 9 was also 4x taller, meaning 16x more force to correct a lean. A little burp would send the rocket right back up in the air.
If you know that something can be done, and there is a potential market for such a project, it then becomes easier to get the funding. Chicken or the egg...
One thing we also need to point out, is that SpaceX uses like 80% of their yearly launches, for their own communication / sat service. This gave a incentive for that investment.
Is the same reason why, despite SpaceX throwing those things up constantly, there really is a big lag of competitors with reusable rockets. Its not that they where / not able to quickly get the same tech going. They simply have less market, vs what SpaceX does non-stop. So the investments are less, what in time means less fast development.
SpaceX is a bit of a strange company, partially because they used a lot of the public funds to just throw shit at the wall, and see what sticks. This resulted in them caring less if a few rockets blew up, as long as they got the data for the next one with less flaws. It becomes harder when there is more oversight of that money, or risk averse investors. Then you really want to be sure that thing goes up and come back down into one piece from the first go.
A lot of projects funding are heavily based upon the first or second try of something, and then (sometimes unwisely) funding is pulled if it was not a perfect success story.
Dragon 9 was based on conservative and boring technology but it was cost optimized before it was reusable, then reusability crushed the competition.
For that matter, Starship is boring. "Throw at the wall and see what sticks" isn't "trying a bunch of crazy stuff" but trying a bunch of low and medium risk things. For instance, development of the Space Shuttle thermal tiles was outrageously expensive and resulted in a system that was outrageously expensive to maintain. They couldn't change it because lives were at stake. With Starship they can build a thermal protection system which is 90% adequate and make little changes that get it up to 100% adequate and then look at optimizing weight, speed of reuse and all that. If some of them burn up it is just money since there won't be astronauts riding it until it is perfected.
This is where I think the business acumen came into play. Because the govt is self-insured, it allowed SpaceX to pass the high risk off to the taxpayer. Once the tech matured, the risk was low enough to be palatable for private industry use.
And FWIW, I don’t mean that as disparaging to SpaceX, just an acknowledgment of the risk dynamics.
The Space Shuttle was wrong in so many ways, not least that it was a "pickup truck" as opposed to a dedicated manned vehicle (with appropriate safety features) or a dedicated cargo vehicle. Because they couldn't do unmanned tests they were stuck with the barely reusable thermal tiles and couldn't replace them with something easier to reuse (or safer!)
Attempts at second generation reusable vehicles failed because rather than "solving reuse" they were all about single-stage to orbit (SSTO) [2] and aerospike engines and exotic composite materials that burned up the money/complexity/risk/technology budgets.
There was a report that came out towards the end of the SDI [3] phase that pointed out the path that SpaceX followed with Dragon 9 where you could make rather ordinary rockets and reuse the first stage but expend the second because the first stage is most of the expense. They thought psychology and politics would preclude that and that people would be seduced by SSTO, aerospikes, composites, etc.
Funny though out of all the design studies NASA did for the Shuttle and for heavy lift vehicles inspired by the O'Neill colony idea, there was a sketch of a "fly back booster" based on the Saturn V that would have basically been "Super Heavy" that was considered in 1979 that, retrospectively, could have given us Starship by 1990 or so. But no, we were committed to the Space Shuttle because boy the Soviet Union was intimidated by our willingness and ability to spend on senseless boondoggles!
[1] The first few times the shuttle went up they were afraid the tiles would get damaged and something like the Columbia accident would happen, they made some minor changes to get them to stick better and stopped worrying, at least in public. It took 100 launches for a failure mode than affects 1% of launches to actually happen.
[2] https://en.wikipedia.org/wiki/Single-stage-to-orbit
[3] https://en.wikipedia.org/wiki/Strategic_Defense_Initiative (which would have required much cheaper launch)
I wonder what the STS system would have been like if the DoD's cross-range requirement hadn't been imposed.
I wouldn’t say anything has fundamentally changed in the rocket coordination tech itself, just the private sector being able to rationalize the cost of the trials with ROI
inb4 blue origin / DC-X did it first
This Honda landing neither went to space nor was orbital, so it was a similar test to the DC-X test.
Besides SpaceX, its also being worked on by Rocket Lab, Stoke, maybe Blue Origin, and too many Chinese companies to count.
so now the main problem is building the hardware, there are a lot of solutions for the software part.
Before there were no general-purpose simulators, and barely usable computers (2 MHz computer with 2 KB of memory...), so all you could do was hardcoding the path and use rather constrained algorithms.
I think there is also a distinction to be made between offline (engineering) and onboard computing resources. While onboard computers have been constrained in the past, control algorithms are typically simple to implement. Most of the heavy lifting (design & optimization of algorithms) is done in the R&D phase using HPC equipment.
Mass-produced hardware drove prices down, and availability way up, in many industries: motors, analog electronics, computers, solar panels, lithium batteries, various sensors, etc. Maybe reusable rockets, enabled by all that, are going to follow a similar trajectory as air transportation.
It would seem to me that Intel and AMD were not friendly to custom designs at that time, and MIPS was not significantly evolving.
A fast, low-power CPU that can access more than 4gb and is friendly to customization seems to me to be a recent development.
While cool and all, this type of sim is a tiny, tiny slice of the software stack, and not the most difficult by a long shot. For one, you need software to control the actual hardware, that runs on said hardware's specific CPU(s) stack AND in sim (making an off the shelf sim a lot less useful). Orbital/newtonian physics are not trivial to implement, but they are relatively simple compared to the software that handles integration with physical components, telemetry, command, alerting, path optimization, etc. etc. The phrase "reality has a surprising amount of detail" applies here - it takes a lot of software to model complex hardware correctly, and even more to control it safely.
* Better motors for gimballing
* Launch-thrust engines that throttle down low enough and preciesly enough for landing
* Better materials to handle stress for flip over manover etc without added weight
* More accurate position sensors
* Better understanding and simulation of aerodynamics to develop body shape and write control algorithms.
> Launch-thrust engines that throttle down low enough and preciesly enough for landing
In large part this is due to improved simulation- spaceX made their own software: https://www.youtube.com/watch?v=ozrvfRHvYHA&t=119s
Experimentation was also a large factor- pintle injectors have been around for a long time, but were not used in production rockets until SpaceX (who moved from a single pintle to an annular ring). Pintle injectors are very good for throttling.
> Better materials to handle stress for flip over manover etc without added weight
We're still using the same materials- good ol inconel and aluminum. However 3d printing has made a pretty big difference in engines.
More rockets use carbon fiber, but that isn't new exactly and the main parts are still the same variety of aluminum etc. Titanium has become more common, but is still pretty specialized- the increased availability was probably the biggest factor but improved cutting toolings (alloys and coatings) and tools (bigger, faster, less vibration) have also made a big difference.
- Advances in rocket engine design & tech to enable deep throttling
- Control algorithms for propulsive landing maturing (Google "Lars Blackmore", "GFOLD", "Mars Landing", and work through the references)
- Forward thinking and risk-taking by SpaceX to further develop tech demonstrated by earlier efforts (DC-X, Mars Landing, etc.)
Modern simulation and sensor capabilities helped, but were not the major enabling factors.
So they need to "hoverslam", that is, arrive at the landing pad rapidly decelerating so that their altitude hits zero just as their speed hits zero. This was thought to be very hard, but I don't think SpaceX has lost a stage due to estimation failure there. It helps that there is significant throttle range and fairly rapid throttle response on the engines, so they can have some slack. (Plan to decelerate at 2.5g for the last ~20s or so, with the ability to do anything between ~1.5g to 4g, so you can adjust throttle based on measured landing speed.)
Their Superheavy has more engines, allowing them to bring the TWR below 1, enabling hovering.
One major reason for this is the mixing plate at the top of the combustor. Fuel and oxygen are distributed to tiny nozzles which mix together. The better the mixing, the more stable the burn. If you get unstable burning -eg momentarily better mixing in one area- it will cause a pressure disturbance which will further alter the burning power in different areas of the combustion chamber. At low throttle, this can be enough to cause the engine to turn off entirely.
Fluid simulations have made a huge difference. It's now possible to throttle engines down to 5% because mixing is much more stable (manufacturing improvements in the nozzles have also helped) and combustion is more protected from pressure variations.
The extra stability also just makes it easier to control a rocket period. Less thrust variation to confuse with drag properties, less bouncing, better sensor data.
I guess I’m trying to connect the dots on how a simulation improves the actual vehicle dynamics.
Simulation inside the engine can find resonances, show where shockwaves propagate, and show you how to build injectors (pressure, spray etc) so they are less affected by the path of reflections. Optimizing things like that smoothly along a range of velocities and pressures without a computer is not very feasible, and you need a minimum of computing power before you start converging to accurate results. The unpredictability of turbulence means low-resolution simulations will behave very differently.
Modern pressure vessels can reach 5% empty mass, thats a factor of 20
Rockets have stages, a good approximate is to stage half your rocket to get rid of the most empty mass. This also means your first stage has to have double the thrust to lift itself and its stage. Now you're at a factor of 40 just to hover.
Now you actually have to take off, usually around 1.2 to 1.4 thrust to weight.
So a more realistic scenario means your rocket engine has to throttle down to exactly 2% power while the laval nozzle is optimised for takeoff thrust only.
SpaceX Merlin 1D: ~40% Rocketdyne F-1 (Saturn V): ~70% Space Shuttle Main Engine (RS-25): ~67% Blue Origin BE-4: ~20–25%
Falcon 9 does the "hover slam" where they have to turn off the engine exactly at touch down, or the rocket starts to go back up again. Throttle is too high for the weight of the booster at that point in flight.
They linked details to look into in their original post.
This means that 3d-printed copper (alloy) is an amazing process and material for them. You can build the kind of structurally integrated cooling channels that the people building rockets in the 60's could only dream about, and it's not a gold-plated part that required a million labor hours to build, it's something you can just print overnight.
There might be more in a year or two (New Glenn, Neutron, Starship, a Chinese one), but for now, I would call it extremely difficult, not easy.
In the past, there was not much reasons to go into space, commercially, so who would have paid for it? But today there are many more use-cases for sending things to space that are willing to pay for the service.
Reusable, propulsively landed stages for rockets capable of putting payloads into Earth orbit is stupendously harder. The speeds involved are like 10-100x higher than these little hops. The first stages of Falcon 9 and Starship are still the only rockets that have achieved that. Electron has only re-used a single engine.
I mean for/example the Apollo lander was a tail landing rocket and lunar landing is way fucking harder because a thick atmosphere gives you some room for error.
Most launch suppliers just make rockets single-use and write it off because it's not like you're launching weekly. Who knows how much it costs in labor and parts to refurbish landed rockets, it's probably cheaper to just keep making new ones.
^ you know what to say in response to this; we're all in the process of finding out which one is more correct.
Instead of news.honda.com (their actual domain) or hondanews.com (actual domain, redirect from before, all owned by them, also has news) or honda.global (makes sense, but nothing there) or honda.com/news (makes sense, but nothing there) they go waste money on a new gTLD. So we have global.honda/en/newsroom/. .
At least they're using it: https://domainmetadata.com/list-of-all-honda-domains
But, couldn’t specifically tell if this was indeed the first launch or not, and perhaps there were some private failures before - anyone know?
I want the NSX edition.
Note that they don't appear to have an orbital engine yet—this thing's far too small, it has to be some kind of one-off for this demo flight. Most of the competition leaped directly to testing an engine they were developing for orbital launches, in their suborbital hops.
It’s like a four minute mile. Now we’ve seen reusable rockets work, everybody builds them and nobody says it won’t work?
A booster / orbital vehicle, when it appears, should have very different characteristics. I can even imagine that some kind of compatibility standard may arise, allowing to stack custom orbital vehicles to reusable boosters, much like the standardized buses for smaller satellites that exist today.
SpaceX' Starhopper was an orbital Raptor engine. The *test vehicle* wasn't orbital, but, it's testing the in-development orbital engine and associated plumbing under flight conditions (which is useful, because... well you can see the various ways Starhopper failed at the start). Likewise, Grasshopper before that, in 2012-3, was a single Merlin engine (the Falcon 9 has, eponymously, 9).
SpaceX never flew a suborbital hop with anything other than an engine intended for orbital flight.
I think if Honda had an orbital-class reusable engine at the hardware stage, that'd be flying that to test it as much as possible. I'm not aware of any of the competitors doing otherwise. This is signalling they don't (yet?) have one.
edit: Or LandSpace, whose 10 km suborbital hop last year flew one of the methane engines their orbital vehicle has nine of.
"you meet the nicest people on a Honda" <https://www.vintag.es/2017/09/you-meet-nicest-people-on-hond...>
I don't know what kind of people you meet on that other, better-known, reusable rocket company.
I wonder if BPS .pace got further with his solid fuel thrust vectoring? Mustn't be far off that if not. https://bps.space/products/signal-r2
https://global.honda/content/dam/site/global-en/topics-new/c...
Why is that? Is it due to the nature of chemicals it uses?
Military rockets, and solid-fuel boosters like the kind the Shuttles used to use, indeed produce very visible exhaust, because they use heavy fuels, and sometimes heavier oxidizers, like nitric acid. This is because they need to be in the fueled state for a long time, ready to launch in seconds; this excludes more efficient but finicky cryogenic fuels used by large commercial rockets.
The large plumes that you usually see the first few seconds when a rocket is blasting off a launch pad are mostly water vapor. The launch pad would be destroyed by the exhaust were it not cooled during the launch by large amounts of water, which gets evaporated instead of the concrete.
But an impressively smooth landing regardless, and I would imagine maybe harder the smaller the rocket is.
From another article.
You likely weren't being exhaustive in your listing, but I first started watching aerospace development with Armadillo Aerospace, and some of their rockets were much smaller. Their largest one was still shorter than the dc-x.
[edit] the camera angle and the camera height from the ground is different as well between the lift off and landing.
It makes more sense than someone going out and grabbing them during the short flight. Those things would need to be sturdy and attached to not melt or blow away during the launch, and they would be hot.
edit: If you open up the first image on the submission and look to the left of the crane, you can see what look like the risers. They do seem to come out of the ground. You can see the same trees as the landing shot.
edit: I didn't realize the page had more videos under the Download button. I was wrong about the rectangles, but you can definitely see it's landing in a different spot in the onboard video (#3). You can still see the risers when it lands.
Someone must have run out and grabbed the risers.
Nope.
https://global.honda/en/topics/2025/c_2025-06-17ceng/image_d...
Video three and four clearly show it lands a little bit away from the risers. Same pad, but only 1/2 comments--not mine--suggested it was a different pad.
It might just be ethanol/oxygen.
I wonder if that's the optimal design for VTOL rocket landers? Or is that more particular to smaller lighter rockets and eventually you need heavier duty options for bigger rockets?
Also the DC-X was eventually intended to be single-stage-to-orbit (SSTO). Do any of these reusable rockets plan on being SSTO? Whether from Space-X/Blue Origin or this or the Chinese ones? SSTO is where you're going to dramatically change the economics of rockets, as you now only have to worry about refueling when launching satellites, instead of using an expendable second stage..
https://en.wikipedia.org/wiki/List_of_Internet_top-level_dom...
Rocket Labs has recovered (not reflown) several orbital boosters, and the rest are within 1-2 years of orbital booster recovery attempts.
Pure HN distilled
Why the huge release of steam from the top of the rocket at the end? Release of heat that builds up during the descent? (Though it's not depending that fast, so it wouldn't be heat from atmospheric friction.)
I'd really like to see them scale this up commercially quicker than they did with the humanoid robot they built well ahead of many others.
brianbreslin•4h ago
oldpersonintx2•4h ago
reaching an altitude of 300 meters
...but this isn't one of them, yet
stego-tech•4h ago
wingspar•3h ago