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back to article NASA joins ESA dark stuff hunt

NASA has signed on for a European Space Agency project to send a telescope to the L2 earth-sun Lagrange point in 2020, to investigate dark matter and dark energy. L2 is a spot where the gravity of sun and Earth will keep the spacecraft in a stable orbit in Earth’s shadow behind the Earth (relative to the Sun). Once stationed at …

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Coat

headline

IRTA 'dark staff hunt' and thought they were weeding out the sith infiltrators, or lizard people...

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FAIL

Forever eclipsed.

"L2 is a spot where the gravity of sun and Earth will keep the spacecraft in a stable orbit in Earth’s shadow."

Except that it's not in shadow: L2 is too far away from Earth for the Sun to be hidden behind Earth. L2 sees a bright ring of Sun around Earth all the time, a permanent annular eclipse. L2 is in Earth's antumbra.

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(Written by Reg staff)

Re: Forever eclipsed.

Thank you. I will correct this.

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Re: Forever eclipsed.

I suspect that it's not really relevant that it may be shaded, the real purpose of placing it at L2 is that it is gravitationally stable so the reflectors and sensors in the telescope are not subjected to gravitational distortion (and so are more accurate).

The reduction in overspill radiation from the sun is a bonus, but not really the main reason as it could be fairly easily filtered form any data collected.

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Alien

Just for arguments sake...

Shouldn't we equip these crafts with lasers and missiles?

Damn! Got to lay off that Faster Than Light game...

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Re: Just for arguments sake...

"... lasers and missiles?"

Nukes.

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Happy

wonder if they will get there before Jame Webb.

Given that it has swallowed $8Bn already.

One hopes so.

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Alien

L2

You sunk my battleship. Wait, no, that wasn't a battleship.

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Headmaster

Unstable...

L2 is not stable, although a halo orbit close to (not around) L2 is. At L2 a modest expenditure of delta-V is occasionaly required to nudge it back into place. The same applies to L1 and L3.

In contrast, L4 and L5 are far more stable. Not perfectly so, because of perturbations (mainly from Jupiter and Saturn), but far less correction is required than for L1, L2 and L3.

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Boffin

Which L2?

"NASA has also suggested stationing a manned craft at L2 to control a robotic moon mission"

Isn't that the Earth-Moon L2 position, not the Earth-Sun one?

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pja

Which L2 -

- My thoughts exactly! pat a

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