Aerospace Engineering - Tumblr Posts
I found the thing to dunk on Elon for regarding the rocket launch.
A lot of experts in the rocket community were questioning Elon's decision not to create a flame diverter.
For those unaware, huge rockets like this usually have giant trenches underneath to channel the flames, exhaust, and debris safely.
NASA's Kennedy Space Center has a flame trench that is 571 feet long, 58 feet wide, and 42 feet high and is built with concrete and refractory brick and bisects the pad at ground level.
But giant trenches are costly and can make working on the rocket on the launch pad inconvenient. So Elon wanted to try forgoing the flame diverter even though he was launching the largest rocket ever built with the most exhaust ever output.
And now he covered an entire town with a layer of rocket dust.
Exploding the rocket was normal and expected.
Not giving a shit about the town around the launch site... fucking infuriating.
The key problem with this notion is that, unless you're using reactionless/"gravitic" thrust (a.k.a. Bullshit Space Magic), you need a lot of volume for propellant because there is no medium to push against in space. That's why human-carrying spacecraft are mostly propellant: it takes a LOT of reaction mass to get around up there.
Even with FTL handwavium and a high-efficiency fusion drive, you still need plenty of compressed gas for maneuvering and a fair bit of volume for reaction mass to get you and your vessel to match velocity with your target. Remember: EVERYTHING in space is moving, all the time. Our closest star, Alpha Centauri, is moving at almost 50 kilometers per second relative to our sun! Our second-closest star, Barnard, is moving more than TWICE that fast. Saturn V, one of the most powerful rockets ever built, had a total Δv of about 18 km/s, and half of that was expended just getting from the surface to low orbit.
Not to mention that, even if you ARE using handwavium FTL and "gravitic" reactionless thrust, you'd STILL need quite a bit of volume for fuel because that stuff would require an extremely large amount of energy.
Submitted via Google Form:
I saw in some sci-fi fiction that there are some small spaceships that just a single person can use. These things are slim and you are basically lying down because it's literally that tiny. The only thing is, I've only seen these used for travelling short distances (i.e. within view) / combat. I was wondering if I could use such a sleek and tiny design as a normal spaceship that can travel FTL. I'd say travelling 10 light years would take just a single minute. Exactly how advanced would tech like that need to be? In this way, a larger ship or crew isn't necessary if you have no cargo you can't carry on your person (helped by making use of shrink rays). Is there any example of a sci fi civilisation that you think could have such tech that can do that I could draw inspiration from or have an idea of what how advanced I'm trying to do?
Tex: A Doylist explanation for these might be that they are analogues to personal vehicles, so are limited by the writer’s and readers’ expectations of personal vehicles, such as the need to use chemical fuels in order to use them. FTL, as a general rule, relies more on momentum than it does acceleration - our current theoretical models mostly rely on the use of exotic particles to fuel suggestions such as the Alcubierre drive, Krasnikov tubes, etc (Wikipedia).
Ten light years in a minute is easily traversed under these conditions, particularly if the technology were perfected to the point of mass production. This seems to also function as your unit of measurement, so you would be able to use this for all technologies of the same type within your worldbuilding. Because of the nature of FTL drives, they would not be unreasonable large (think of how much we’ve scaled down modern computers!), and you could conceivably compare them to the gasoline engines that are currently in the majority of our modes of transportation today. There are many, many, many variations on the theme of spaceships, so I’ll list some of the major franchises that have percolated popular perception of this technology for comparison:
Star Trek, Category: Spacecraft classes
Star Trek, Category: Starship classes
Battlestar Galactica ships
Stargate Tau’ri fleet
Stargate, Category: Hive ships
Stargate, Category: Spaceships
Star Wars, Starship (Legends version)
Wootzel: For examples in media, you may want to check out the TV Tropes page on FTL in media, and maybe even the Analysis Page on the same (this one gets dense at first, but further down the page there are a lot of examples of “types” of FTL tech that other creators have used).
If you want to have small ships that are capable of FTL, and you think it’ll serve your story or something about the theme of your world, then do so! Just pick and choose whatever rules and limitations you want in your world that suites you. You can pull inspiration from other works, or just think about what will work for you and make up your own conventions. Just note down what the tech requires and what limits it, and keep that consistent in your story so you don’t contradict yourself, but otherwise do whatever you’d like.
you're right and you should say it
i’m not going to go on one of my huge tangents but this guy literally has no idea how anything related to space travel works, does he.
this thing can barely get into Earth orbit, and he’s already talking about interstellar travel? with what infrastructure? what engine? chemical???? even if you were to double the size of his “starship”, it wouldn’t even be able to get to anywhere past Jupiter in my opinion
Personally I'm a big fan of
Δv = (Iₛₚ•g₀)•ln(m0/mF)
but I have a number of friends who prefer
L = CL•A•0.5•r•v²
for the funny aspec people in my machines