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About ChrisSpace

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    Spacecraft Engineer
  1. SpaceX Discussion Thread

    So I just watched the full video of the launch with my mother, I had to explain lots of things to her but she seemed excited too. I'm still very surprised at all of this. I mean, this had been postponed for half a decade, I was certain FH wouldn't fly until the next decade at least. Soooo, does this mean SpaceX might launch something at Mars at the next launch window?
  2. Anyone watched "Europa Report" yet?

    I remember watching it on Nelflix in December 2014, and I absolutely loved it. Personally I consider it a good halfway point between The Martian and Space Odyssey: Voyage To The Planets.
  3. For Questions That Don't Merit Their Own Thread

    Okay, here's what I meant: The Dv required to reach 0.5c is 0.5775c The Dv required to reach 0.9c is 2.0646c The Dv required to reach 0.99c is 7.01811c Thus we can take relativity out of the equation by first reducing velocities by, say, 100,000 to the following: 0.0000 km/s at T+0 years 1.7313 km/s at T+2 years 6.1900 km/s at T+4 years 21.0398 km/s at T+6 years Now you can see more clearly how the acceleration gradually increases. From this, it should be possible to calculate the initial and final acceleration, then multiply those by 100,000 again.
  4. For Questions That Don't Merit Their Own Thread

    So I have some questions about this video. If we assume that the ship's timeline (0.5c at T+2 years, 0.9c at T+4 years and 0.99c at T+6 years) is relative to Earth, and taking the effects of relativity into account: 1. Assuming no Dv remains after T+6 years, what is the initial and final acceleration of the vessel? 2. From the mass ratio (easily calculatable from question 1) and the Dv required to reach 0.99c (which is a lot more than 0.99c), what is the Isp of the propulsion system?
  5. It's more of a genocide weapon than a planet dissolver. (this goes for most other options too) But enough to significantly change the orbit of, say, Mars for example. Enough to collide it with Earth, possibly. 15km/s? Even diverting something from the Kuiper Belt would take a tiny portion of that. Make a small dyson swarm around the sun and aquiring energy won't be a problem. It takes far less energy to build such a weapon than it would to destroy a planet with it.
  6. Okay, here are my ideas, ranked from least to most destructive: 11. Slaughterbots Mass produce these ( once they've been developed. Wiping out most of the planet's population should be doable with enough resources and funding. 10. Send nukes If the world's nuclear arsenals are brought back to the sizes they were at in the 80s, less than 20% of the global population could be left alive after the initial nuclear exchange and nuclear winter, especially if the warheads are "salted" with cobalt. Also try using nukes to set off some supervolcanoes. 9. "Blight" You know that thing in Interstellar that was killing all the world's plants? Turns out that can actually happen. In theory at least. I have two ideas for which specific pathogen can be used, both of which should be able to take out maybe 90% of the planet's population. 8. Extreme climate change By releasing every drop of potential greenhouse gases in the Earth into the atmosphere, we could render most of the planet uninhabitable to all but maybe 5% of the population. 7. Drop a rock To simplify, this method involves changing the orbit of an asteroid or comet so it impacts Earth. By far the best candidate for this is the comet Swift-Tuttle, although that would require more propellant than you could possibly carry up there, so an ISRU system using the comet's ice for hydrogen or hydrolox propellant would be required. It also would require hundreds of meganewtons of thrust, so the only realistic propulsion method would be a vast array of chemical or nuclear-thermal engines. 6. Snowball Earth Remember how one of the ideas for terraforming Venus involved using a giant mirror at the L1 point to block out the sun, so the atmosphere would freeze and stuff? If we did that to Earth, the planet could become a solid block of ice very quickly. Still, in well-insulated habitats and underground, maybe 2% of the population could survive. 5. Genetically engineered pandemic This is the first idea on this list that I think might actually have a possibility of killing the entire planet's population. The genetic codes for Ebola, Avian Flu, Marbug, SARS and many others are all available online, as are the locations for the last 2 samples of smallpox, and instructions on how to modify existing pathogens. 4. Antimatter Producing enough antimatter to kill the world's population and destroy most of the global biosphere is... probably possible, but would require vast amounts of power and energy. 3. Grey goo Can a swarm of tiny, self-replicting machines consume the entire Earth's biosphere? Maybe. Could we build such a thing? Not sure. 2. Nicoll Dyson Beam Turn the sun into one of these and focus it's energy onto Earth. This is the only way I can think of that the planet could be physically destroyed. 1. Call for help If some genocidal AI or extraterrestrial regime wanted to destroy Earth, I'm sure they'd be even more creative and motivated then I am. Honorable mention 1: Chlorine poisoning It's number 9 on this list: Genetically modifying the algae to do this sounds difficult, though. Honorable mention 2: Black Hole Even producing a tiny black hole the size of an atom is far beyond our capabilities.
  7. I'll use my Porg as a companion, also as a scout to keep an eye out.
  8. Make a wish... and have it horribly corrupted!

    Granted. It contains a virus that uploads your entire search history onto all your social media pages. I wish I had either the Rocinante or ten Porgs.
  9. The Ctrl+V thread!

  10. Random Science Facts Thread!

    It would cost about 4.585 trillion dollars to buy all the land offered by "the lunar embassy". What? Tell us more! Would it be possible to build it up faster artificially? Asking for a friend. What do they look like? Where can I get this? ...How?! Edit: Whoops, didn't see the link until I posted this.
  11. Designing our own Spacecraft

    All the cubsat stuff I mentioned can be found here: You can find anything from cameras to decouplers to the stuff I mentioned earlier there. As for landing, we could get a bit more creative than simple parachutes. A deployable hang glider could glide the capsule down onto a runway, for example. As for propulsion, there are a wide range of interesting tricks that can be done. For example, the "rocket" part of an RPG-7 provides about 338.9N of thrust for 2.39 seconds, so it could be used for stage separations, for example (remember to take the explodey bit out first). Another idea is to make a "rocket candy" engine, which could potentially have an Isp of up to around 125s. Or we could go with commercially-available SRBs, which can surpass 6kN in some cases. Or we could do what these guys did to make an 8kN engine: or what Copenhagen Suborbitals is doing for it's space program. Regarding safety, an ejector seat could be used to get the pilot to a safe distance in the event of an emergency during liftoff or landing. From here onwards my ideas start to become more speculative... Miniature submarines and ultralight aircraft come in many different shapes, and while we'd obviously remove propellers and other air/sea stuff we don't need, the rest can stay intact. Just cover it with sheet metal and Aluminum, or some other cheap metal.
  12. Designing our own Spacecraft

    I have ideas like this too, but for a slightly different setting. Seems a bit arbitrary. There are currently 3 space programs capable of lifting 24 or more metric tons in a single launch. Rather than building a completely new crew compartment from scratch, my idea is to use a pre-existing, commercially available vessel with built-in closed-loop life support systems. In other words, build the spaceship parts around a miniature submarine or aircraft. Reaction wheels, transmitters, antennas, computers, batteries, solar arrays, transceivers, navigation equipment and other stuff can be aquired from cubesat harware suppliers. Although I'm not sure if equipment made for a satelite one ten-thousandth of the size of our vessel will still work. I have quite a few ideas for solid, hybrid, liquid and cold-gas thruster modules. For example: Data Sheets.pdf Data Sheets.pdf