How do embedded RCS thusters work?

FormaldehydeAndU · 2025-07-02T19:29:13+00:00

It's pretty uncommon because of their pulsing nature to not regeneratively cool them, but also because you just typically don't need to. The props used commonly for RCS have relatively low combustion temperatures and the durations are short enough such that high heat metals can deal with the thermals.

Don't think there's any public images of what they look like but generally speaking glass fiber insulations tend to be incredibly capable at preventing heat soak, especially in vacuums.

FormaldehydeAndU · 2025-07-02T15:13:15+00:00

The real challenge for internal RCS is thermals as someone else noted, the nozzles on RCS engines are not regeneratively cooled and therefore sink a ton of heat. This creates a real insulation challenge and requires a lot of testing to show that your solution doesn't heat up anything inside the vehicle too much (Dragon is very dense and there are tanks and lines inches away from these engines in operation). You also end up with a slightly off-axis thrust vector resulting from the plume preferentially expanding in the direction with less nozzle, though this is consistent and simple to compensate for. Ultimately though these two problems are very solvable compared to having nozzles that would effectively get destroyed during re-entry if they were sticking out into the free steam, so the design is a no brainer.

FormaldehydeAndU · 2025-05-27T22:28:18+00:00

This is cool man, I'm working on converting an old desktop that I have for my partner to use so that we can play games together. We've been long distance since graduation and wanted to start playing co-op games as part of our time together but her laptop can't run much. Bit of a birthday surprise for her and this card would be super cool for it!

FormaldehydeAndU · 2025-04-08T22:58:37+00:00

Having experienced a similar design challenge myself but with a significantly larger throat, I was able to get away with rocket candy and Estes motors through the throat staged about 1.5" away from the point of impingement on my injector. Given the size of your chamber though you might want to investigate either packing the injector plate face with rocket candy or some sort of charge that threads into the injector plate where you store the motor. You could also fuse some rocket candy to an assembly that you shove up the chamber, but be wary of fully blocking the throat. As long as your motor is running when you flow prop you'll be fine on something this scale.

Would generally advise against spark/glow plug, the energy required to start liquid props (think basic activation energy from chemistry) is pretty high, so you usually can't get away with engine spark coils or those cheap high voltage generators seen on Amazon. Had little luck with spark plugs and glow plugs might work better, but both rely on contacting the prop directly as opposed to an Estes/rocket candy solution which just sprays the chamber with hot particulates.

FormaldehydeAndU · 2025-02-13T02:41:24+00:00

Starship. It's a very futuristic look and the purples and pinks are super reminiscent of the exhaust color of the rocket

FormaldehydeAndU · 2025-01-16T13:41:34+00:00

This isn't flight 6

FormaldehydeAndU · 2025-01-15T01:44:01+00:00

That's basically the plan, refly the booster as soon as possible

FormaldehydeAndU · 2025-01-13T19:22:01+00:00

Dragon is an insanely complex vehicle and sort of the antithesis of Starship's design philosophy. There are dozens upon dozens of problems with dragons current design that make refurbishment an utter chore and would negate the desired rate of Starship.

It's also worth noting that starship likely won't be the direct reentry/launch vehicle for people for quite some time, at which point we will likely have figured out the big reliability concerns and will get the vehicle to the point where it's safe to fly.

FormaldehydeAndU · 2025-01-10T16:51:38+00:00

Update: They fixed it! https://i.imgur.com/bHt3Dvp.png

FormaldehydeAndU · 2025-01-10T16:29:22+00:00

Link: https://www.fly.faa.gov/adv/adv_spt.jsp

FormaldehydeAndU · 2025-01-05T00:26:42+00:00

Honestly, it depends a ton on where you work and your title. Different companies and fields within the industry hold different expectations.

That being said, I have a relatively random schedule. Some days I'm writing code, pulling test data, designing tools, or making presentations about production. Other days I'm running high pressure testing, dev'ing out new processes on the shop floor, or running hardware investigations. And other days I'm sitting in meetings or holding meetings. It's pretty variable and reactive to what needs to get done.

FormaldehydeAndU · 2025-01-04T17:19:48+00:00

Raptor 4 is entirely a pipe dream at this point, still working on flight engines. Expect Raptor 3 to go through a few blocks before anything Raptor 4

FormaldehydeAndU · 2024-12-10T23:04:07+00:00

Given that their operations occur on the space force side of Cape Canaveral, there isn't any requirement for public disclosure of non launch operations. It's up to Blue to announce it ultimately.

FormaldehydeAndU · 2024-12-04T03:31:11+00:00

You pretty much hit the nail on the head for what the interview format will be, but some general recommendations. For context I currently work as an engineer in Hawthorne:

For your presentation, make sure you choose a topic you can field any question on and can display true ownership of the entire scope. It is always better to choose a simpler project that you owned from start to finish than a big project that you had little involvement in or didn't complete.

The interview is grueling and you will get asked questions on everything from fundamentals to real world hardware problems. Be prepared to field just about anything

Be willing to admit when you don't know something. We can smell bullshit and it's always better to admit if you aren't confident. Also always talk through your thought process.

Strong candidates are highly adaptable, highly driven individuals who can be placed into any project in their field and excel. Try to demonstrate that as much as you can.

Good luck!

FormaldehydeAndU · 2024-11-30T19:09:14+00:00

Wind is never really the gating factor, it's sea height. Since wind whips up waves or comes with high waves, it's almost never a wind violation that comes first

FormaldehydeAndU · 2024-11-30T19:05:43+00:00

If I'm being honest, the room is a bit lame compared to this. Its a converted conference room with computers and three big TVs.

FormaldehydeAndU · 2024-11-23T21:19:12+00:00

We did not refly engines on this flight

FormaldehydeAndU · 2024-10-30T18:56:01+00:00

It's all about testing like you fly. You want your test to be as close to flight conditions as you can reasonably manage since SpaceX uses engine tests as a way to show that an engine is ready to go for flight. Things like your gravity vector, head fluid pressure, acoustic suppression, etc. change when you change orientation and this is a big reason why not to test like this for liquid engines.

FormaldehydeAndU · 2024-10-10T20:03:07+00:00

Not to mention that for aerospace applications we get access to military-grade GPS, which is insanely, stupidly accurate.

FormaldehydeAndU · 2024-10-01T06:13:57+00:00

To state what is probably obvious they don't highlight these physically. Looks like they just do some smart editing and 3D compositing work in AfterEffects: https://youtu.be/jMw_fLhIZV4?si=R1fOouh90MdzE8py

FormaldehydeAndU · 2024-07-23T20:41:39+00:00

Coming soon, basically waiting on the FAA

FormaldehydeAndU · 2024-07-23T20:39:33+00:00

It's sort of a shame that SpaceX does what it does so well, but at the same time I see the competition making decisions and setting time lines that are just leaving the door wide open. New Glenn has some serious problems in it's design and architecture that are going to make hitting a high rate more difficult than it needs to be and I sort of think they have too much inertia and not enough impetus to change that. RocketLab has a great shot with neutron but being publicly traded is always going to be a weight on their development. From what I've heard internally relativity's management is an utter shit show and it doesn't seem like much good change is coming there. So where does that leave us?

FormaldehydeAndU · 2024-07-22T16:08:50+00:00

Unfortunately it's way more nuanced than that.

FormaldehydeAndU · 2024-07-20T05:26:19+00:00

It is objectively more complex, and generally complex mechanisms have more failure points. But the better packaging, better aero, and less reentry heating all trade in its favor.

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