"pinch tiny parts of Earth's energy"
That's what they say, but they really just want to make the day longer so they can sleep in a bit longer!
India's Mangalyaan Mars Orbiter Mission - or MOM as we like to call it – has laid another perfect orbital egg. Mangalyaan is headed to Mars on a shoestring budget of just $US74m, a pricetag made possible by its plan to pinch tiny parts of Eartt's energy by dropping into our gravity well and using its rocket boosters to sling- …
The MOM has a perfect shape, so no chucking, I am sorry.
This is a particularly perfect action, and probably the way to go as budgets bite. And we learnt it from the NASA boffins, who so cunningly used a bit of energy from Jupiter, Saturn, Neptune and Uranus to power on the Voyagers.
So: nothing like chucking. Just a bit of Indian spin innovation, even if we borrowed it well.
Only one thing to add: Thank you NASA, for the help and encourageme
MOM is really using a Hohmann transfer orbit, which is a German 'invention', but really it's just doing the maths based on the work done by Newton and Huygens and others.
I'm not sure anybody can claim that they invented certain low energy orbital transfers, it's more about discovering what was already dictated by the laws of physics.
As in many things, the Soviets got their first. The theory of gravitational assists was published in the USSR in - incredibly - 1925 and was first implemented by Luna 3.
But NASA has to get the record - Cassini has done something like one hundred slingshots around the Saturn system.
Bloody forriners, stealing our energy, slowing us down when it's almost winter.
And now they are going in to Our own God-given space, taking it all over - no common sense these days. I blame Gordon Brown!
(goes off to post Kipper- type tirade on the Mail's website)
Nice one folks -- go for the scenic route and save a fortune.
I do not believe it is possible to 'pinch energy' or perform a 'slingshot' maneuver when the spacecraft is bound to earth's gravity. Traditional slingshots, like those performed by the Voyager missions, involve sun-orbiting spacecraft stealing momentum from other planets using close fly-bys. This isn't possible if you are simply in orbit around the earth.
What MOM is doing is using a Hohmann transfer orbit to increase altitude. By performing burns when the spacecraft is at perigee, they are gradually raising it's apogee. This will eventually allow for a smaller burn to take the craft to mars then if they did one large burn once achieving orbit.
It's not about 'stealing energy', it's about efficient orbital mechanics.
Actually, I'm a little wrong here. By performing burns when the spacecraft is closest to the earth (and thus having the highest velocity) they are taking advantage of the Oberth effect. The Oberth effect states that you will achieve the greater increase in kinetic energy by increasing delta-V when an object is travelling fast the when an object is travelling slow.
So, the most efficient way to achieve a higher orbit is to perform multiple, short burns as your orbit comes closest to the earth. Once your apogee is high enough, THEN you perform a 'Hohmann transfer' by performing a burn at apogee.
Again. No slingshot and no 'stealing energy' from the earth. Just efficient use of propellant.
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