AckSed

Landspace's methalox Zhuque-2E launched recently:

It's rather like the fact that Europa Clipper would not exist without John Culbertson pushing for it, because he is a science geek: https://arstechnica.com/space/2024/10/were-finally-going-to-the-solar-systems-most-intriguing-but-unexplored-frontier/ 'They' have these qualities 'we' have heard about, so there must be an angle that matches, to complete the image. They can't care about it, because look at all the other things they've done. The new hires at SpaceX come in believing that Mars is a cover for making rockets, but discover that both Musk and Shotwell are serious about it.

I don't think it's healthy for them, for sure: it's a FB conversation of a few old uni friends I occasionally mark "Read", only dipping in when I've braced myself enough and the last response isn't too cynical and matter-of-fact, "We're so smart, they're sleep-walking into this, why don't they see?" or words to that effect. And round and round they go, posing their cynicism as rebellion. I've stopped going to the monthly catch-ups.

This particular circle of friends is invested in their opposition, their hate. I have found myself keeping very quiet whenever space innovation (which is inevitably SpaceX) comes up.

The key thing I'm interested in here: Zubrin's refutation of the meme-complex that the Mars colony, and the entire motivation for SpaceX (and Blue Origin's aspirations of an O'Neill cylinder), is a way for all the billionaires to leave Earth and the proles behind to our fate. Which is straight out of Ben Elton's satirical Stark. Granted, I haven't seen it lately, but it was entrenched in my circle of friends just a year ago, because (the feeling went) there must be a motive that lines up for all this effort. Now it's switched to, "Work in the mines for the megacorps on Mars and die."

About an axis, my bad.

Thinking out loud here, and trying to say why this is still troubling me: we - humans - do not have an internal component that can spin freely about an axis and that tries to apply a counter-force to the outside frame. We have levers attached to hinges. Sure, the momentum transfer of bringing one arm in can impart a force that rotates. But can we impart a net positive rotation or will swinging our arm out again exert an equal force that exactly matches and brings us back to the start? In both cases, either the drill of your example, a set of gyroscopes or our muscles do use external energy (electricity or stored chemicals), so it may not match to my classical Newtonian intuition. Which is why I want to see it tried.

In this context rotation is moving along about an axis with a start point and desired end point, while spin is uncontrolled, continuous rotation.

To further pin it down, we're assuming that this works by shifting their centre of mass, and rotation can be cancelled out by moving back again in exactly the same way.

We need to define the experimental setup. We have: One (1) human in a spacesuit; Floating in microgravity (Lagrange point for preference); At rest with zero movement; In full vacuum. We assume: Absent any external force, with no air to push against, the astronaut can, by moving their arms, torso and/or legs in some combination, impart a rotational movement and thus change their orientation. The question we're asking is: is this true?

We're approaching "reverse sprinkler" in the intersection of intuitive/counterintuitive.

Given the recent Scott Manley vid on New Shepard, my mind has been poisoned. I cannot avoid seeing this raising, and lowering, and raising once more as... suggestive.

More details here (English) with picture of the ruined test building: https://japannews.yomiuri.co.jp/society/general-news/20241126-224488/ Seems they were testing a second stage that also had problems (blew up) last year. Epsilon S is an interesting rocket. It's an Electron-class launcher that can launch a fair bit (1,400kg) into LEO with very few personnel needed. The first stage is the SRB on the new H3: https://en.wikipedia.org/wiki/Epsilon_(rocket)

Huh. Just watched the Everyday Astronaut compilation of Flight 6, and the bent comms tower was bent before it lifted off, not after.

Don Pettit is 1) known for performing interesting little science experiments every single time he's gone to space 2) on the ISS right now (as the oldest current NASA astronaut!) 3) is on reddit and X (https://x.com/astro_Pettit). He'd definitely be up for it.

Med kits, tinned food, even a cassette tape have been discovered in the storage lockers of the Skylab Astronaut Trainer, untouched for 50 years: https://www.msn.com/en-us/news/technology/skylab-time-capsule-revealed-50-year-old-artifacts-discovered/ar-AA1qyjoM

Well yes, but also no. The force of an arm or leg moving in free space is insignificant compared to the power and precision of a gyroscope/reaction wheel. Granted, our primate ancestry makes us OK at brachiating from one handhold to the next in microgravity, or using footholds to anchor a weightless body. The real trick would be adding a cybernetic prehensile tail, for three points of contact and leaving hands free. A brachiating service robot is an appealing idea.

Since Flight 5, two different Lunar Rovers have signed up with SpaceX for delivery by Starship: https://payloadspace.com/starship-hired-to-fly-two-lunar-rovers/ When I saw the official stream it was delayed a bit - something like 5 seconds after EA's live stream. It might have ended early if they discovered the communication problem with the tower at that moment and decided to ditch then, out of caution.

Transcript: https://payloadspace.com/an-interview-with-sir-peter-beck-rocket-lab-ceo/ Key takeaways: First test of Neutron will be roughly in the middle of 2025, aiming for a splashdown. Expect a similar number of launches year-on-year to Electron's start; Have a backlog of HASTE hypersonic missions; Walking around the engine test facilities, and team was doing a cryo test on a Neutron tank; "...two-thirds of the total investment of the rocket program is in that infrastructure, that steel and concrete in the ground."; Built a production line for Archimedes first, which was riskier. Everything coming off was intended for flight - software, avionics, the whole engine down to the valves; 200-300kg payload of Electron and 13,000kg of Neutron kind of the sweet spot. Electron is not going away; Interviewer says, based on what he's seen around, that development was around $350 million. Have to be a visionary with a product that people want to buy, and it's like running through a maze with dead-ends holding people with shotguns; have to stick your head out, but also not die. "...some companies worry about millions of dollars, we worry about cents. Like everything is accounted for and is really, really well controlled." Have to have a coupling between business decisions and engineering, because "physics doesn't care about money [...] engineering execution is the real leveller."; Interviewer mentions Musk's decision to make Starship pointier, even though it had no advantage. Beck says he did the same thing with Neutron's fairing, because the optimised shape looked terrible: too bulbous and phallic. It's slightly better aerodynamically, slightly heavier; All aspects of the business are doing well, not a case of 'oh, now I can breathe easier' after the SDA contract; Always intended for RL to be a space systems company. "...the very second Electron that we launched had recesses in the kick stage for solar panels to turn it into a satellite."; Acquisitions e.g. Sinclair (produces reaction wheels) are to allow them to scale. In service to scaling, recent hire of automotive industry person Frank Klein as COO (decades of experience as a manager for Daimler AG, Magna Steyr AG and most recently Rivian); Neutron’s important to [RL] as they're looking to disrupt the launch monopoly and medium class launch with end-to-end spacecraft, satellite design and launch. The large space companies of the future will build whatever satellite they need at scale for their own applications, launch their own stuff and have unimpeded access to space; "...bringing scale to the space industry is something that’s really, really sorely lacked. And I think the one thing that Rocket Lab is really good at is very, very difficult things to produce and deep tech components and systems."; "I think whoever turns up with a working rocket in a really constrained market is going to be everybody’s best friend."; As space stations become commercialized and there’s more destinations, demand will happen over time. Not right now, not with one provider and one destination; Not as strong a market on lunar payloads. Changes, becomes "very, very interesting" if the Chinese gain a footprint on the moon; They are incredibly passionate. However, "If you’re starting a [space] company, don’t fall in love with the technology." (fricking ouch. That's the entire reason I follow this stuff. :-/) Restates position that RL is meant to be a multi-generational space company that is enduring, even after he leaves. That said, he's living the dream.

The new RL10E-1 uses 3D-printed thrust chamber for a 98% reduction in part-count: https://www.l3harris.com/newsroom/press-release/2024/11/l3harris-delivers-new-generation-rl10-rocket-engines I'm startled by the size of the vacuum nozzle, though Wikipedia says that's average. Looks cleaner, though it's still a chandelier-o'-gear on the powerhead.

Thank you for digging in, then.

More on The Exploration Company: https://arstechnica.com/space/2024/11/how-real-is-this-european-space-startup-that-aims-to-launch-astronauts/ https://payloadspace.com/european-space-capsule-biz-wins-160m-round/ I can sorta see the capsule coming to pass, and the management is certainly aware of how little time they have. I choose to hope.

Musk says that they lost comms with the launch tower computer, and that's why they aborted:

Anything you can do...: https://spacenews.com/china-quietly-tested-its-first-inflatable-space-module-in-orbit/ An interesting test (even if it does look more like an inflated beachball), but a technical detail is that Shijian-19 had a total mass of 3.5 tons, and the payload of the recoverable section was 5-600kg. An unknown portion of it is still up there, possibly with the test module still attached.

Sudden flight of fancy had me imagining rocket pirates "aggressively salvaging" downed rocket stages, and they've just struck gold. Edit: Sadly, it was then sunk: