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Domain: m6.net

Stories and comments across the archive that link to m6.net.

Comments · 8

  1. Re:Some recommendations from another Math Ph.D by ari_j · · Score: 3, Interesting · on Good Physics Books For a Math PhD Student?

    Download Orbiter, launch a flight to Titan, and on the way there read the included PDFs regarding Dynamic state vector propagation and the like. Fewer pages, more direct and obvious application, etc.

  2. Re:2011? How long with ion drives? by Anonymous Coward · · Score: 0 · on Messenger En Route To Mercury

    Does anyone know how to, given a number of forces applied in arbirary positions with arbitrary angles to an object for a given amount of time, determine the rotational and linear accelerations on the object? I've checked a number of physics texts, and none of them address this problem.

    I don't remember the details, but I saw in an old physics book a long time ago that the way this is done is to convert an off-center force into an equivalent on-center force and torque. It involved adding two additional equal-and-opposite forces, so that now there are three, such that one is on-center and the others are parallel and equidistant from the center of mass. Those two can then be converted into a torque.


    Ask the guys here. This is a forum of users of what sounds like the program you want to write. Maybe it already exists, and you don't have to write it. Anyway, this program already exists, and does simulate off-center forces.

  3. Re:Space vs. Weightlessness (clarification) by ari_j · · Score: 3, Interesting · on SpaceShipOne 100 km Attempt Slated for June 21

    Time for my standard response that makes people hate me for getting them hooked:

    First off, the reason we fly straight up and then sideways is that it's a lot easier to accelerate sideways at 70km than it is at 0km altitude, because of the thinner atmosphere. Since the only significant delta-V in an orbital launch is the tangential component, you can tune your ascent to minimize fuel requirements and save up for the big sideways burn.

    Now, for the fun part: Orbiter is a free (as in beer + SDK for making your own ships) space-flight simulator that is both mathematically accurate and visually stunning. It includes the space shuttle Atlantis (don't even bother starting out with that one, as it takes practice to get to orbit) and some fictitious spacecraft capable of getting you to Mars or even beyond.

    You can even look around online and find add-ons such as my latest favorite, an Apollo mission including a pretty realistic cockpit complete with the Apollo computer system. You even have to do your own LEM extraction and so forth.

  4. Re:Apathy again! by antispam_ben · · Score: 1 · on Amateur Rocket Reaches Space
    I'm going to plug a great simulator for you all, and that is Orbiter. You'll learn a ton about astrophysics just by starting the program up and trying to get into orbit your first time, and it won't quit from there.
    Phuque. That's all I need, yet another timesink.
  5. Re:Apathy again! by ari_j · · Score: 3, Informative · on Amateur Rocket Reaches Space

    Orbital craft are launched straight up because it is inefficient to try to accelerate tangential to the Earth's surface at low altitudes, due to the air density. They fly more or less straight up to about 30km before really pitching over to start the tangential acceleration into a periodic orbit (as opposed to a once-through orbit like the one you enter when you jump off the ground). Low earth orbit basically begins around 130km, where the atmosphere has thinned out enough that you can remain in orbit. I think the ISS is in the 230km-300km range.

    I'm going to plug a great simulator for you all, and that is Orbiter. You'll learn a ton about astrophysics just by starting the program up and trying to get into orbit your first time, and it won't quit from there.

  6. Re:Cut 'n' Dried by linzeal · · Score: 2, Interesting · on The Flickering Mind

    Games help tremendously. We just need to make them more realistic. I have pimping it a bit today but I like the orbital flight simulator aptly named orbiter and have personaly used it to demonstrate aerobraking for a space science class. When you can get most software at 80% off or so online as a student or faculty there is no real execuse not to use the software that professionals in the field actively use now to begin famaliarization with them.

  7. Best NT and best *nix hosts in sub$10/month range by afflatus_com · · Score: 2 · on On The Subject of Web Hosting
    Have been sampling hosts for 5 years now, and finding the best is always a long search. The sub $10 category is one that I know well.

    If you want NT cheap, take M6 Technologies. www.m6.net Mediahouse site stats 5 are outstanding, a nice control panel to add/delete/config your emails, database at no cost, more megs and bandwidth than you'd ever use, cgi-bin is there and runs perl scripts well (something have had problems with NT hosts elsewhere). Speed is good, support good (though they don't work weekends). $10 setup, $10 a month. Superb.

    If want *nix cheap, Hurricane Electric www.he.net is the best in town. PHP over mySQL database tossed in. $9.95 a month, $19.95 setup. Support pretty good, though their $9.95 is advertised as "self-serve", and this philosophy pretty well holds. Noticed they have started running adverts (the 'groovy' banners) on Slashdot also lately.

    All the best, Robert

    ---
    "And the beast shall be made legion. Its numbers shall be increased a thousand thousand fold."

  8. A very good NT webhost is... by Cody+Hatch · · Score: 1 · on On The Subject of Web Hosting

    ...M6 Hosting.

    If you want NT webhosting, they've got most of the bells and whistles (ASP, databases, index server, unlimted mailboxes, big account sizes, let you use custom components, etc.) pretty cheaply. The tech support is good, and I've ALWAYS got an answer within 24 hours.

    Very good pricing structure too--like it's a one time (small) fee to register a component, and any updates changed to it are free. Most of the stuff is like that--small up front fee, no montly charge. Better than some places (which will go unmentioned) which charge HIGH monthly fees for everything.

    Oh, and I'm not affiliated with them. :-)