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Posts posted by RCgothic

  1. 3 hours ago, ZooNamedGames said:

    They're trying to. It's called Starship & Super Heavy. So far it won't stop exploding. That, along with SpaceX only flying for a short duration, makes NASA apprehensive to contract out flying crews to the moon.


    Dragon 2 is 9500kg dry. Throw out the normal payload to ISS and give over to propellant. Stretch the trunk, give it some superdracos at 235 SL ISP. Call it +2000kg lunar dry weight, some of which is consumable but we'll ignore that, and 11000kg of propellant.

    Starting mass: 22500kg, Dry 11500kg. Superdraco can push that through 1550m/s and do both the lunar insertion and return (~1400m/s) with margin.

    Falcon 9 can launch 22.8t expendable. Falcon 9 is man-rated.

    Falcon Heavy can put S2 (~4000kg) plus a notional 1000kg docking module into LEO expendable, with 58000kg of residual propellant. MVac has 348s.

    Starting Mass: 85500kg, Dry 27500. MVac can push that through 3870m/s, which is again easily enough for a lunar intercept (3260m/s).

    The only new engineering here is a stretched trunk with superdracos on, plus a docking target on S2. And it goes to LLO, which is better than NLHO.

    Tell Musk: Get crew to LLO by the end of 2021 for half the price of an SLS or the world ends and I'd back him to succeed.

  2. 54 minutes ago, tater said:

    Herd immunity is sort of a thing, the more people who have had the disease before, the fewer people can be infected. Ie: you're in a group, and would infect 4 people, but if 2 of them already had it and are immune, you only infect 2. The R0 for you just dropped in that case from 4 to 2.

    There's an old idea, Farr's law of Epidemics that says that all are bell curve shaped (in given wave, anyway).


    The "on order of common flu is literally correct (same order of magnitude), but it's high for flu at 0.2%.

    The principle concern still remains our parents (for those of us here who are older), or our grandparents (for you young 'uns).

    Herd immunity means if a virus normally spreads to 5 other people, but 90% are immune, then each infectee only infects half another person and the infection dies or over time. Which means the 10% who aren't immune mostly never encounter it.

    For Covid19 nobody is immune. In order to reach herd immunity first a massive number of people need to get infected. Which is a disaster for a disease with 1-2% mortality.

  3. 34 minutes ago, DDE said:

    Herd Immunity is absolute rubbish when it comes to Covid19.

    In the absolute most charitable interpretation, it's basically "vulnerable people need to hide until Coronavirus has run it's course through the healthier and more resilient segment of population".

    UK govt policy is to stand back and watch people die. "Oh dear, so sad, never mind."

  4. Yup, a barely useful mission has been designed for SLS because it can't do anything more useful with the throw weight and capsule it has.

    It will require multiple launches of other rockets to complete that mission, so why not just go the whole way and just use other rockets?

    SLS can't do anything that a falcon 9 and a falcon heavy can't do much cheaper and much more often just by working together.

    Falcon 9 is man rated. Astronauts will literally be on the next dragon flight.

  5. Once again, the threat here isn't that the virus is particularly deadly. In the grand scheme of things it's not. But it is very infectious, nobody has immunity, and enough people are going to get it at once to overwhelm healthcare systems.

    When that happens it's going to get very bad indeed, so any effort put into flattening the curve or expanding healthcare capacity is not wasted.

  6. That's such an obvious thing to have it's a wonder the idea wasn't developed.

    I guess at the moment it's only relevant to the ISS which has its own lifeboats. And if Starship has an issue on orbit they'll probably just send another starship. Maybe the utility of that idea had a window that's gone.



  7. Read an article about the potential for a rescue mission to Columbia on Ars, assuming the critical damage had been noticed soon enough. Only Atlantis or Arianne V-159 had any hope of reaching Columbia before its consumables expired. But the Arianne had already mounted Intelsat 907 a ressupply probe couldn't have been thrown together and mounted inside a month. 

    If similar happened today I bet SpaceX could do it though. They have enough hardware and the right "get it done" attitude.

  8. Alien bacteria are going to be exceptionally lethal to any foreign organism. Interstellar civilisations like The Federation would be pretty much impossible. Attempting to colonize a planet that already has life on it sounds like a very bad idea. It'd be easier to take a nearly life-bearing planet and terraform it the rest of the way.

    If I absolutely had to live on a planet that had something else on it first? Complete nuclear sterilisation of the surface.

  9. https://www.teslarati.com/spacex-starlink-ambitions-save-space-station-delays/?fbclid=IwAR1vjmLLtEghs-JfFq5ySf3sy4giprmKCovOHXeSiHezhrsidYVfif3fYjY

    I know we already know about the second stage swap, but it pretty much couldn't have happened without SpaceX's ambitious internal market for Starlink launches that can take a back seat if necessary.

    Starlink is directly improving SpaceX's service to customers. That's pretty impressive!