AngrybobH

Car power port chargers usually use a quick and dirty method to drop the voltage down(and cheap ones can cause push button start cars to not start because of noise). They use a zener diode. It allows current to flow through the diode the wrong way at the fall over voltage. A 5v zener will leave 5v on the circuit and flows the rest to ground. A little wasteful but it gets the job done. F to V converters (frequency to voltage, comes as a single chip, reversible, super cheap) can do like what @magnemoe was saying. Cheapest way is a simple voltage divider if you know the input voltage is constant(ish)(12v----58% of ohms total----5v output ----42% of ohms total----ground). There are also DC/DC converter chips sold in chip form(these are used in just about everything). Expensive DC/DC converters add all the circuits for reduction in noise and clean output. The choice comes down to what you are powering, how many watts you need, and how clean you need the power. Additional concerns might be what environment you are running it in and how long you need it to work for. 100 amps continuous in a harsh environment with a super clean output for a decade is a very expensive problem.

Just a guess but over-torqued bolts could do this. Torqued past yield the bolt will lengthen under load and then stay that length making the bolt effectively loose.

I'm excited about all of it, but most of all, for in space construction!

Ahead of schedule? Is that an anomaly? Do they need to roll it back now?

Yeah, funny that I live in west Texas and I need an 8 hour lead time. I would love to be there when it goes (or goes off). Wife and kid aren't even remotely interested so, a solo drive for me. On that note, they did say they were not going to do road closures on the weekends, right? And that means a monday to friday only launch?

That was fun. Cheering for a crash is seldom the right thing to do.

I was thinking about this small versus wide lane road thing. I'd say I agree with the studies and all but, I have a counter example. One I should have thought about before. I currently live in west Texas. The roads here have wide lanes. When I first came to this place I remarked that one lane is as wide as two lanes (with only a tiny bit of exaggeration). I learned to drive in central Massachusetts. The lanes there are tiny in comparison with hills (real hills unlike west Texas hills) and curves. I once was driving in Boston with the flow of traffic. Traffic conditions were congested and the road was not straight. I was moving about 90MPH with about an inch between my right mirror and the left mirror of the car next to me and less than a car length in front or behind me. A narrow curvy road with buildings close to the curb did not slow down traffic. In west Texas, I routinely drive on a road with a posted speed of 45MPH. This road has 3 lanes in both directions and a turn lane, the buildings are set far back from the road. It is almost never congested. But, almost every time I drive on this road there are vehicles driving side by side at about 15MPH lower than the posted speed (which is common on all roads down here even the highways). Wide, straight lanes with buildings set back does not speed up traffic. Quick stat look up says Texas has 33 million people and about 4400 traffic deaths a year. Mass has 6.9 million people with 400 traffic deaths per year. This makes me wonder about the studies of roadways. I'd agree if/when someone says the US does it wrong but, there has to more to it than roads alone, as I have said before. The Texas vs. Mass example makes me think speed has nothing to do with it but straight wide roads makes people think they don't have to actively participate in driving 100% of the time. Would be nice do have but it's pretty much a no go in the US.

I don't disagree with either. I do remember reading about the studies during the pandemic lockdowns. It's really interesting but, lockdown traffic and pre-lockdown traffic general behavior isn't exactly an apples to apples comparison. I do believe they are close enough to draw some conclusions and generally agree with the findings. My earlier comment was to point out that while better roads would help, better cars and drivers are needed. Possibly even less drivers by way of better mass transit and better designed roads/cities(for pedestrians). Only fixing one of them could leave results lacking.

I don't disagree with you at all. But I seem to remember a study that showed, statistically (yeah, I know), that speeders pay more attention and have less crashes but worse crashes when they do. So, speed kills is still true but I wouldn't put most of the problem on speed. I would put most of the problem (in no particular order) on poor driver preparation (not knowing where they are going), poor driving ability(they give licenses to nearly anyone), driver inattentiveness (cell phones that connect to your car!, radio, french fries, .....), Lack of perceived danger and responsibility (cars are safe but not 100%. Every time you turn the ignition on you should think "I could die or kill someone" because driving can be dangerous), large to oversized vehicles (harder to control, gives a sense to drivers of more right of way than is deserved), and roads, like was mentioned. And sure, speed kills.

I did the same. Man I wish you watched it and posted before I watched it. I want my time back. Bad doesn't even come close to describing it.

All those can be done with the ship rotating (sure it's more difficult). And wouldn't you have to stop rotating (the whole ship or the rotating assembly) for attitude adjustment prior to burning the engines because spinning things and gyroscopic forces?

Yes. In the automotive world (where I work) there many different solutions that work well and could potentially be adapted. Thinking variable camshaft timing actuator and solenoid setup, similar to what @RCgothic said. Non-contact inductive power transfer could also work. But, I do wonder, why rotate a piece of the ship? You could just make all the stuff fixed and rotate the whole thing. I would think a little gravity would help with things like fuel tanks and water recycling.

I'm surprised that wrench doesn't have a Cummins part number on it. Mixing units happens all the time with them. Recently I had to run a volume and pressure control solenoid test on a Cummins 5.0L that requires replacing a fuel rail banjo bolt with one that has an AN fitting on it. the banjo section was 14mm but the AN was 9/16 (which is just enough larger than 14mm and too small for 15mm). I haven't use a 9/16 wrench in probably more that 10 years.

I'm not sure but I would guess that they are load spreaders for the crane that was there. Wood is the super high tech way to do that, or so I have found.

The knowledge required to go from standing naked in a field to wearing synthetic clothes and video chatting with someone on the other side of the planet inside a temperature controlled room is really what is required for ISRU. To say it's vast would be an understatement. This is a subject that fascinates me but I don't have the education required to add to it meaningfully. I do though have some random thoughts. If you think about the ways to get power(heat or electricity), it is possible to end up in a situation where you have an excess. Especially when you don't really need to worry so much about environmental damage (can't make the moon MORE dangerous for instance). I'm not dismissing the difficulty of heat and power management but, say on the moon for it being close, enough stuff can be sent to have plenty of power. That makes aluminum...I want to say trivial. But that leads to the thought of radioactive materials. If you have fission reactors on the moon, can you refuel them with locally sourced materials? (a quick search revealed an article from 2009 about the discovery of uranium on the moon, so maybe). If everything comes down to heat or electricity, wouldn't power be the most important? With enough power we can always use the preferred human method of brute force for anything we need. Also, if you have aluminum (non-oxidized) but you need iron (unsure of how you would end up in that situation) and all you have is iron oxides, thermite is a fun and exciting reaction that lets off some heat.

Not necessarily. My tinkering with zinc-air was nearly 10 years ago(oh sh... it was more than that, I'm feeling old now). You would think that someone has an idea of a material that can be used. It doesn't even matter if that material is super expensive because that side of the battery is not consumed. It does seem most of the research was done when lithium batteries weren't what they are today but with the better environmental impact of zinc vs lithium(and cobalt) you would think someone is still working on those. I do know there is a company still trying for iron-air batteries. I think x-air batteries can be better than li-ion just got to wait for someone with funding to figure it out.

Zinc-air batteries (and other x-air batteries like iron-air) can offer many solutions but like stated specific power is lacking. There was a bus company in California (can't remember the name) that was doing research into bus scale zinc-air batteries. They discovered the graphite side (oxygen gathering) limited the O2 into the battery and not the quantity of O2 in the air. They theorized that a different configuration of carbon was needed, like graphene. I'm not sure they solved that, but that was not the biggest problem. The best electrolyte they found was KOH (common in alkaline batteries) but as large scale zinc-air batteries discharged the potassium reacted with with the air(mostly the CO2) and the electrolyte was precipitating out of the solution (pretty sure they haven't solved that one yet). The best part of most x-air batteries is the ease of recycling (also , if you want another rabbit hole to fall down, zinc-air can be made into a hybrid flow battery). Used zinc for instance just needs heated and it will reject the oxygen. You just got to solve the other problems and you could be a zillionaire. I once built a crappy zinc air battery mostly because the materials are cheap and I like to tinker. Zinc from boat sacrificial anodes(or rub the copper off a penny), KOH from the chemical store (KCl for water softeners is also usable), and graphite from the art supply store, plus a cup and you could make your own too. Amps per cell is very low but ~1.2V (1.65v/cell is what it was supposed to have) isn't bad.

Yeah. all I could think was 'BOING'.

Projectile B would need more dV to keep the same trajectory as A because the drag on B would be significant.

https://www.youtube.com/c/pbsspacetime/videos lots of black hole stuff there and that question is answered. I just don't remember which one. It was a fairly recent one though.

Either that or they flat out lied. At this point I'm not sure which is the safer assumption.

When I lived in a much colder part of the world my neighbor had a driveway like that. I was envious because all I had was a cheap shovel. Also, car engines try to use all the heat they make to push the pistons down not make things warm. They are not very efficient heaters.

I always took this project as the fusion reactor of tires. I wouldn't hold my breath about these being put on regular everyday cars anytime soon. I could be wrong, but note the article says there no word on price and since there is almost no margin on tires I would bet, if they get them to work, they will be expensive mostly because they can. Cost will keep the manufacturers and car owners away even if they end up better in every other way. As for the tire manufacturing process, I was under the assumption that the natural rubber (that is absolutely required) was the only problem resource. I can't imagine Canada having large quantities available.

1. 50/50 weight distribution is somewhat common in mid to high range cars. they handle much better than front heavy vehicles. Add in advanced traction/dynamic control and you have a car that could drive out of such a maneuver if the traffic/road conditions were right. 2. The PIT maneuver is more about overloading the lateral traction of the rear axles' tires than overall weight. If a heavy vehicle had worn tires(or a poor choice of tires) on it a PIT could be even more effective. 3. Rear and/or mid engine cars usually have a 50/50 distribution. I once owned a Pontiac Fiero it was a 45/55 distribution. The second the rear tires lost traction it would flip directions. A PIT on that car would be super effective.

Yep. Same here I have also always noticed this but lately it has been very slow. (Fast PC, fast internet, firefox) It has to be twitter but this is the only place I come across tweets embedded or otherwise.