On May/6/2018 at 3:47 PM, JF Mezei wrote :
On 2018-05-06 15:19, Scott M. Kozel wrote:

So did they launch it to the south or to the west? Going west they
would incur a big energy penalty due to the rotation of the Earth.


Could they launch straight up, and once above some safe altitude, then
veer east? After having flown for X seconds, aren't the odds of an
explosion way down and thus considered safe to fly over land?

It could be done. But it would be less efficient than going south for a
polar orbit how much less efficient depends on how high up one goes
before going east. And you would probably have to go very high up if you
have a conservative definition of when it is possible to over fly
populated land in a safe manner.

or is the eastward speed from earth's rotation lost as you ascend
straight up (lost to atmospheric drag) ?

No the eastward speed is not loss, the atmosphere rotates with Earth so
atmospheric drag won't cancel the eastward speed.

You don't lose eastward speed but you have big gravity losses. Once you
achieve orbital speed horizontally you no longer have to spend fuel just
to stay up and you don't have gravity loses any more. You want to get to
that point as fast as possible. But by going up first than accelerate
horizontally, it takes more time to reach orbital velocity horizontally
and you have more gravity loses.


Alain Fournier