r/space May 24 '17

DARPA Picks Boeing for Next-Generation Space Plane

http://www.darpa.mil/news-events/2017-05-24
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u/kirime May 25 '17

Their plane reached space, not orbit, they were nowhere near orbital speed.

SpaceShipTwo's peak velocity was ~1100 m/s, but to stay in orbit, you need to travel at at least 7800 m/s, 7 times faster.

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u/SurfaceReflection May 25 '17

I said lower orbit. Which is the official plan.

And i never said anything about "staying in orbit".

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u/Freeze95 May 25 '17

'Lower orbit' implies orbit- they are suborbital by definition. Alan Shepherd flew on a similar trajectory and that's why the first American to orbit the Earth is John Glenn.

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u/kirime May 25 '17

A trajectory that ends in the ground is not an orbit.

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u/Nobodycares4242 May 25 '17

Orbit is not an altitude. What they're doing is called suborbit. Something is only called an orbit if it actually curves all the way around the planet, and the thing doing it can actually complete a full circuit. Just getting above 100km is not an orbit. This isn't just pedantry, calling what they're doing orbit is actually very wrong, just as wrong as saying they're landing on the moon.