Honda conducts successful launch and landing of experimental reusable rocket

Japan continuing their legacy of minituriazing everything they develop. \s

It's much smaller than other suborbital hop vehicles. If it's 6.3 meters, the smallest Starhopper was 18 meters; Blue Shepherd 19 m; China's Hyperbola-2Y 17 m; the Zhuque-3 VTVL test vehicle 18.3 m. Also the Grasshopper from 2012 was 32 m and even 1993's DC-X was 12 m.

> successfully landed its 6.3-metre (20.6-foot) experimental reusable launch vehicle

From another article.

>6.3 m in length, 85 cm in diameter, 900 kg dry weight/1,312 kg wet weight

Its like half the size of a Trident missile.

Several reasons. It's filmed in daylight, so any flame or exhaust will be less visible. The rocket engine is much smaller than anything that would go on an orbital booster, so there's less exhaust than what'd you see for an orbital launch. Also it's looks like it's a hydrolox rocket (using liquid hydrogen and oxygen as fuel), which has the least visible flame. The combustion product is almost entirely water vapor. Methalox (methane + liquid oxygen) is the next cleanest, which emits water, CO2, and a little bit of soot. Kerolox (RP-1 and oxygen) is the most common propellant used today, and it emits a significant amount of soot.

Solid boosters put out the most visible exhaust, as burning APCP[1] emits solid particles of metal oxides. Also some rockets (mostly Russian, Chinese, and Indian) use unsymmetrical dimethylhydrazine + dinitrogen tetroxide, which emits a reddish-orange exhaust. Both compounds are toxic, as is the exhaust.

1. https://en.wikipedia.org/wiki/Ammonium_perchlorate_composite...

Soot means carbon-rich fuel, like RP1, and a very fuel-rich mix. Most launches I ever saw had basically zero soot, and a clean exhaust of a well-balanced fuel / oxidizer mix.

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.

Most civilian rockets have solid strap-on boosters(actual technical term) that emit the signature thick white smokes, as well as leave contrails at high speeds. Neither would be visible for non-solid rockets at low speeds.

Basically yes, other rockets might burn chemicals that create more soot. This one seemingly doesn’t.

Despite the other comments, the landing spot is clearly the same as where it took off. Take a screenshot at 0:09 and one at 0:48 and you can see that it's most certainly the same pad. The camera has moved slightly to the left on the landing, that's all.

Someone must have run out and grabbed the risers.

It may not have landed on the same pad it took off from.

I think the landing spot is different from where it took off from. The trees in the landing shot weren't there in the takeoff shot.

k kg is a funny unit... Much more readable than Mg of course. Tonnes would also work...

Saturn V: 2.9M kg

Blue Origin New Shepard 75k kg

Can you elaborate on the advances in deep throttling?

I recall hearing SpaceX cite manufacturing improvements as well. How do you feel about materials science and the ability to source parts not made of unobtanium?

@roshdodd - Is there a modern reference/book that covers the design of such systems?

I don't think this was the cause. Advanced simulation capabilities have existed for many decades in the industry. Many if not most of those tools are not publicly available.

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.

> so now the main problem is building the hardware, there are a lot of solutions for the software part.

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.

Actually, the DC-X did it first, in 1993. The DC-X was the first vertical rocket landing, Blue Origin was the first vertical landing of a rocket that went to space, and SpaceX was the first vertical landing of an orbital rocket.

This Honda landing neither went to space nor was orbital, so it was a similar test to the DC-X test.

Crappy for 10% amazing for 90%, somewhat better than the 80/20 70/30 seen by most F500s.

Electrical engineer: motors and sensors are not really any better- motors have gotten more efficient and sensors have gotten cheaper, but gold standard sensors like ring laser gyroscopes have existed since the 60s.

> 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.

Its more about money.

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.

Also psychology and politics kept people from following the easy path.

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)

See, for example: 4-minute mile

I mean, SpaceX also knew it could be done since reusable rocket tests happened in the 90s.

What is the point of making a recoverable rocket if not to reuse it (or at least reuse substantial components)?

Rocket Labs, Stoke Space, Deep Blue, Landspace, Space Pioneer, iSpace, Galactic. (The last five are Chinese startups).

Rocket Labs has recovered (not reflown) several orbital boosters, and the rest are within 1-2 years of orbital booster recovery attempts.

I think the DC-X program did this first in the 90s. It ran into funding issues and it turns out there isn't a ton of value in reusable rockets that only go a few hundred feet (although more advanced applications are potentially worthwhile)

That'd be a very impressive service record - Neptune is right around ten thousand times as far as the moon.

A Civic would be on-brand, but an S2000 convertible with an ASIMO waving from the driver's seat would be much more fun.

find an old one, connect the odometer to count the distance flown in addition to the x00k miles it already has, stream the video as it flies around the moon and back.

would be a fun publicity stunt.

perhaps they could launch Elon into space, that would be civic

An inattentive person rear-ended my 82 Civiv in 87. I probably wouldn't still be driving it, but it has led to a long association with Honda/Acura products.

If rockets became as common as cars, what kind of accidents would we see? And would insurers insure them?

If you'd still be driving it then how was the resale value relevant?

The Honda rocket won't be as "fancy" as the SpaceX but it'll have vastly better parts availability.

My experience with Honda has not been great. Both Hondas I have owned had complete transmission failures. Full disclosure, I bought them used (as I do all my cars) with unknown maintenance history and I did get a few years out of each of them so it still worked out "ok" in an economic sense. The engines do seem pretty bulletproof. But I would not buy another, at least not one with an automatic transmission.

Make sure you do a valve adjustment on the Fit engine every 100k or so. Easy job to do with some basic tools and a few hours on a Saturday afternoon.

I read this as "pirate space industry" and got real excited.