Wednesday, December 04, 2013

Spaced Out

There's a few interesting developments in the space world at the moment.

Waitaminute - are those two words (space and world) that should be used together seeing as one is ground and the other is void ?

I've been watching the news reports on the Indian space probe lately. There's two probes going to Mars at the moment, one from India, one from the USA. The Indian one made its people nervous because one of its several "Trans-Mars Injection" burns didn't go to plan.

I've written things about Kerbal Space program before (and I feel I have unfinished business with that game but it's far more amusing to watch the Scott Manley videos). It's simplified at the moment but it's still an incredibly good rocketry and orbital physics simulator. Definitely one where you have to think a bit with the navigation.

Anyway - it teaches you all sorts of things, me being one of those people who learns best by doing. It teaches things like :

Why the Indian probe needed several burns to get to Mars
Why it would split up the burns
Why they send probes to other planets at certain times/dates
Why it didn't really matter if it missed one

Firstly - the certain times and dates ... Everything in space has a path that it goes through. Everything around it influences that path, which makes everything go in slightly wonky ellipses. It's why we have tides, because the gravity of the moon pulls the water towards the moon. It takes time too for the planets to go around their orbits. You wouldn't want to launch your probe when Mars is on the opposite side of the sun. Or maybe you would ...

Things up there happen slowly. If you pointed a rocket towards Mars and hit the Go button, it would miss because in the time taken for it to get there, Mars will have moved around the sky quite significantly. Instead, you aim it towards where Mars will be when you think it'll get there and you factor in how much its path will be curved by the gravity of everything else up there.

There's a phenomenon called the Oberth Effect, which says that if you fire the rocket in orbit, it'll most affect the opposite side of the orbit. Hold up. 2 important terms : Periapse - closest approach, Apoapsis - furthest approach. Oberth means that to escape orbit, it's best to fire the rocket at Periapse because that's the best way of increasing that Apoapsis. And once the rocket is going fast enough, it achieves "Escape Velocity" and will be on its way to Mars.

So why split up the burns, why not go American Style and just do one ? Well - the American one had what all American transport has (lol - I'd love a V8 monster), a whopping big engine, while the Indian one was a bit more modest.

So the Indian one couldn't get all of the acceleration it needed out of the way in the short times it had at Periapse. It doesn't matter that it splits them up, as long as it can do it enough times to get to Mars while it still had fuel to get there.

I think that's enough orbital mechanics for now don't you ?

Yep. Brain. Fizzing. Cooking. Exploding.

Especially when you think of the insane calculations that go on to get the most efficient course to go. They'll factor in every bit of gravity they can to get their rocket in the right place at the right time, without bumping into any planets. If they're really clever, they'll make it fly by lots of different planets. Probes like Cassini-Huygens visited 3 planets (Earth, Venus, Jupiter) before reaching its final destination (Saturn) and when it got to Saturn, it checked out 9 moons. Most of that is set up by the rockets that fling it out there and the math to do it is absolutely insane. Kerbal Space Program is much simpler and orbital maneouvres in that tend to be rather more brute force.

One last bit - why do they bother being so efficient ? Cos it lets them squeeze as many instruments on to the probe as possible. More instruments means more weight, means more fuel needed to get them to the destination.

Ok - that's definitely enough for the nerdy stuff for tonight.

I was going to say something about gaming too. I have that unfinished business with Kerbal Space Programme, where I'd like to make rockets that check out the other planets. My main gaming time at the moment is with that old staple (9 years old ... cor) World of Warcraft. I'm playing on Silvermoon with ally characters. I'm missing the guys and the Hot Swedish Girls of the awesome Draenor guild but I'm enjoying playing through the story as an ally for the first time.

I have to say, since I started playing WoW it's got considerably easier. I thought I'd check this out by sending my character into Outland (where the first expansion is set) completely naked. Ok. Not completely, I let her keep the tabard for modesty. Did I have a problem ? Only with the pet battle. I don't think it'll be as easy when I get to the second expansion but a lot of the challenge has been removed from the game. And that's a big shame. Challenge makes it fun and the challenge as the game used to be was never too much.

I've been very tired lately though. I started playing on Monday evening and lasted a couple of quests before giving up due to tiredness. At the moment, I'm enjoying watching (actually listening) the Yogscast annual Xmas livestreams. I won't be watching all of those (their output varies, they have awesome people and annoying people) but I thought last night's with Hannah, Simon and Kim-Mandrew was hilarious. The videos by Hannah and Kim tend to be pretty special.

Thoroughly enjoyed that. It's gamers enjoying games and bringing you with them when they do. Quite restful too, except when they're playing horror games and unexpected sounds happen.

Right - over to the livestream :-) But ... random piccy !


  1. Been watching some of Hannah's yogcasts. Hilarious! She might just have a new fan.....

  2. I think it has to count as one of those secret guilty pleasures ...

    Not much Minecraft either on the Hannah and Kim channels. Avoid Totalbiscuit though, he has a habit of making me buy games I never play.


So much for anonymous commenting ... If you would like to leave a message and don't have a suitable account, there's an email address in my profile.