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    1. TV Tuesdays Free Talk

      Have you watched any TV shows recently you want to discuss? Any shows you want to recommend or are hyped about? Feel free to discuss anything here. Please just try to provide fair warning of...

      Have you watched any TV shows recently you want to discuss? Any shows you want to recommend or are hyped about? Feel free to discuss anything here.

      Please just try to provide fair warning of spoilers if you can.

      4 votes
    2. Day 17: Set and Forget

      Today's problem description: https://adventofcode.com/2019/day/17 Join the Tildes private leaderboard! You can do that on this page, by entering join code 730956-de85ce0c. Please post your...

      Today's problem description: https://adventofcode.com/2019/day/17


      Join the Tildes private leaderboard! You can do that on this page, by entering join code 730956-de85ce0c.

      Please post your solutions in your own top-level comment. Here's a template you can copy-paste into your comment to format it nicely, with the code collapsed by default inside an expandable section with syntax highlighting (you can replace python with any of the "short names" listed in this page of supported languages):

      <details>
      <summary>Part 1</summary>
      
      ```python
      Your code here.
      ```
      
      </details>
      
      7 votes
    3. Tild-ers who live in developing countries (India,Brazil,Nigeria), what differences between your country and the West would you like to bring to others attention?

      First, I'll start with currency (although this isn't unique, exclusive or universal to developing countries.) In my country a real is 25 US cents and 22 European cents. This effectively means...

      First, I'll start with currency (although this isn't unique, exclusive or universal to developing countries.) In my country a real is 25 US cents and 22 European cents. This effectively means everything made by a US or European company (a lot of things and almost everything technological or of value) is 4 times more expensive for me than for an American/European. This means an iPhone costs 4 thousand BRL but our minimum wage is still around 1000 BRL monthly (4.30 BRL/hour assuming an 8-hour shift) meaning an iPhone costs 4 months of minimum wage in Brazil while in the US it costs less than one. For reference an Indian rupee is a 70th of a dollar and the minimum wage is 164 to 750 rupees daily depending on the state (4920 to 22k rupees monthly) but it still only amounts to 320 US dollars.

      34 votes
    4. I'm freaking out and need advice

      My mother died last month and I've been thinking of leaving my father's house ever since then. I initially thought I'd be okay with doing that, regardless of whether or not my father would object,...

      My mother died last month and I've been thinking of leaving my father's house ever since then. I initially thought I'd be okay with doing that, regardless of whether or not my father would object, but he talked with me last night saying he'd be okay if I left and now I'm FREAKING OUT.

      Background: I'm 23 and living in Houston, Texas. I have an older brother who lives in Dallas who offered to take me in, but it wouldn't be very permanent as he plans on leaving the country for a trip next year and will be gone for some time. I also have a friend from high school who offered me a room, but she lives in Seattle and was fired from her job. No one else who is close to me is able to offer me a place to stay.

      My concerns: I dropped out of college. I was planning on going back but then my mother died and that plan was put on hold, so I don't have any marketable skills (I've only ever worked in retail). I also don't have a job lined up anywhere else. I've never had to take on so many bills at one time and therefore I don't know much about budgeting.

      I'd like to leave, but where I am it's secure and comfy. Maybe it's finally time I pushed myself out of my comfort zone and start taking control of my own life, but I don't want to risk my safety and finances on a crazy idea.

      I welcome any and all advice, and thanks for reading.

      edit: changed a word

      27 votes
    5. What are you doing this week?

      This topic is part of a weekly series. It is meant to be a place for users to discuss their week. If you have any plans, goals, accomplishments, or even failures, whether they be personal or work...

      This topic is part of a weekly series. It is meant to be a place for users to discuss their week.

      If you have any plans, goals, accomplishments, or even failures, whether they be personal or work related, I'd love to hear about them. This is a place for casual discussion about your week, past, present, and future.

      A list of all previous topics in this series can be found here.

      So, what (or how) are you doing this week?

      9 votes
    6. Day 16: Flawed Frequency Transmission

      Today's problem description: https://adventofcode.com/2019/day/16 Join the Tildes private leaderboard! You can do that on this page, by entering join code 730956-de85ce0c. Please post your...

      Today's problem description: https://adventofcode.com/2019/day/16


      Join the Tildes private leaderboard! You can do that on this page, by entering join code 730956-de85ce0c.

      Please post your solutions in your own top-level comment. Here's a template you can copy-paste into your comment to format it nicely, with the code collapsed by default inside an expandable section with syntax highlighting (you can replace python with any of the "short names" listed in this page of supported languages):

      <details>
      <summary>Part 1</summary>
      
      ```python
      Your code here.
      ```
      
      </details>
      
      6 votes
    7. Ask Tildes: Design a spacecraft! You've been offered to submit a space exploration misson, with a cost cap of $1 billion. What is your proposal?

      You've been asked to submit a proposal for a space exploration mission of your own desire, to the New Frontiers spaceflight program. These missions have a cost cap of approximately $700 million to...

      You've been asked to submit a proposal for a space exploration mission of your own desire, to the New Frontiers spaceflight program. These missions have a cost cap of approximately $700 million to $1 billion, and have famously produced the following spacecraft:

      • New Horizons, a flyby probe to Pluto.
      • Juno, a polar orbiter of Jupiter.
      • OSIRIS-REx, a sample return mission to a rocky asteroid.
      • Dragonfly, a drone lander to Saturn's moon Titan.

      These are medium-sized missions in both scope, and cost. You can't build the Mars 2020 Rover, or the James Webb Space Telescope. What do you send, and where? Things to consider:

      Technology Readiness Level

      Administrators are less likely to choose your mission if you choose to integrate risky or untested flight hardware, or novel concepts into the mission design. You're more likely to get selected with more conventional hardware.

      Power Source

      Your best bet is probably solar panels, maybe something commercial off the shelf like NG's Ultraflex panels? The downside is that these are only effective up to about Jupiter's orbit, and generate power according to the inverse square law. How much do these cost and weigh? How much energy do you generate?

      If you go further out into the solar system than that, you'll need a Radioisotope Thermoelectric Generator (RTG). There aren't many of those around, in fact, after Mars 2020 has taken its RTG, there's two left. What makes your mission deserving of an RTG? Is there enough power in the MMRTG to power your mission?

      Propulsion

      Does your mission need in-flight propulsion? Either for orbit insertion, landing, or maybe a long coast with Ion thrusters like Dawn? If the latter, you can get some pretty good Xenon-powered thrusters, like NEXT, which gives you 236mN of force from 7kW of input power (this rules out an RTG as your power source).

      Don't need long-term burn capability? Maybe a COTS bipropellant engine like LEROS is your thing. Watch your weight though, bipropellants aren't efficient! Often more than half the mass of large spacecraft can be dedicated to just propulsion alone.

      Instruments

      Go crazy. What are you looking to research? Do you need a long range camera, a wide angle camera, something outside of the visible spectrum, a spectrometer, ground-penetrating radar? Do you have a mass-budget in mind?

      Launch Vehicle

      Every dollar you save on your launch vehicle, you get to add to your mission profile. Your best bet in terms of performance and cost is probably Falcon 9, which retails for $62-90 million, depending on the amount of assurance for success you need. Of course, if you can find a cheaper launch vehicle, feel free to pick it if it fits into your mission weight.

      Objectives

      What scientific questions do you want to answer? What are you interested in exploring the most?

      13 votes