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Their goal is to create a ship that‘s up to the task of setting up colonies on Mars. Their estimate is that at least 1 million metric tons of cargo to the surfa

Their goal is to create a ship that‘s up to the task of setting up colonies on Mars. Their estimate is that at least 1 million metric tons of cargo to the surface of Mars are required for that. Favorable launch windows to Mars are occurring every two years. With a cargo mass capacity of 100t per ship, over a span of 20 years (=10 launch windows) that would still require 1000 launches per launch window in average. Let that sink in… Since a trip to Mars takes too long, a ship can only go once per launch window. So they would need as many ships as there are launches to Mars in a launch window.

ngngngng 5y ago
Are there really that few launch windows? I assume it's because this ship is larger than the others we've been launching all this time?
- jacquesm 5y ago
  It's all about the proximity of the planets. Not about the size of the ship.
- randallsquared 5y ago
  No, it's because the transfer orbit with the largest payload for the thrust is only available in a specific configuration of Mars and Earth, which only happen every 26 months or so. Note the spacing for launches for Mars missions: https://en.wikipedia.org/wiki/List_of_missions_to_Mars https://en.wikipedia.org/wiki/List_of_missions_to_Mars
- extrapickles 5y ago
  Yes. When you leave is extremely important as its mostly about the relative alignment of the planets. You can trade a massive amount of fuel to get their faster, but waiting a month can sometimes shave 3 months off the travel time. If you left on August 25 2022, you will arrive in July 2023. If you waited 1 month to leave, and left on September 26 2022 you would arrive in May 2023, months before the people who left earlier. This is all according to: https://trajbrowser.arc.nasa.gov/traj_browser.php https://trajbrowser.arc.nasa.gov/traj_browser.php
evilduck 5y ago
I'm not all that familiar with orbital transfers and costs. Given the 20 year time frame and launch quantities needed, is a favorable transfer window always needed (I'm probably asking if it is always cheapest)? Seems like there's going to be stuff being sent up that would be totally fine slowly cruising to Mars in three years instead of one. Receiving a thousand shipments from space sounds approximately as hard as sending them and spacing them out over a longer period might be desired (and given that quantity, let's face it, we're going to crater a few of them into Mars and replacements will need to be sent).
- bryanlarsen 5y ago
  Earth and Mars orbit around the sun. Sometimes they're on the same side of the sun, sometimes they're on opposite sides. Using extra fuel you can make launch windows larger, but they're going to come every 26 months no matter what you do.
- mannerheim 5y ago
  Outside the launch window, you need to spend more fuel, which means less payload. I would imagine sending ships outside the window, even if you can do so at a greater rate, won't help you much in terms of payload, if at all.

ngngngng 5y ago

Are there really that few launch windows? I assume it's because this ship is larger than the others we've been launching all this time?

jacquesm 5y ago
It's all about the proximity of the planets. Not about the size of the ship.
randallsquared 5y ago
No, it's because the transfer orbit with the largest payload for the thrust is only available in a specific configuration of Mars and Earth, which only happen every 26 months or so. Note the spacing for launches for Mars missions: https://en.wikipedia.org/wiki/List_of_missions_to_Mars https://en.wikipedia.org/wiki/List_of_missions_to_Mars
extrapickles 5y ago
Yes. When you leave is extremely important as its mostly about the relative alignment of the planets. You can trade a massive amount of fuel to get their faster, but waiting a month can sometimes shave 3 months off the travel time. If you left on August 25 2022, you will arrive in July 2023. If you waited 1 month to leave, and left on September 26 2022 you would arrive in May 2023, months before the people who left earlier. This is all according to: https://trajbrowser.arc.nasa.gov/traj_browser.php https://trajbrowser.arc.nasa.gov/traj_browser.php

evilduck 5y ago

I'm not all that familiar with orbital transfers and costs. Given the 20 year time frame and launch quantities needed, is a favorable transfer window always needed (I'm probably asking if it is always cheapest)? Seems like there's going to be stuff being sent up that would be totally fine slowly cruising to Mars in three years instead of one. Receiving a thousand shipments from space sounds approximately as hard as sending them and spacing them out over a longer period might be desired (and given that quantity, let's face it, we're going to crater a few of them into Mars and replacements will need to be sent).

bryanlarsen 5y ago
Earth and Mars orbit around the sun. Sometimes they're on the same side of the sun, sometimes they're on opposite sides. Using extra fuel you can make launch windows larger, but they're going to come every 26 months no matter what you do.
mannerheim 5y ago
Outside the launch window, you need to spend more fuel, which means less payload. I would imagine sending ships outside the window, even if you can do so at a greater rate, won't help you much in terms of payload, if at all.