LIVE! Final Ariane 5 Launch Countdown

The Launch Pad ^ | July 5, 2023 | The Launch Pad

[Morgana]

LIVE! Final Ariane 5 Launch Countdown LIVE STREAM

[Alberta's Child]

It’s remarkable to see a rocket named after white supremacists.

Oh, wait a minute … that’s Ariane, not Aryan. :-P

[God luvs America]

wassup with that background music??

[Red Badger]

Where’s it going? and What’s it carrying?..............

[Red Badger]

Wagner?..................

[Steely Tom]

They did such a splendid job with JWST. The precision of their orbital placement added years to the useful life of the telescope.

[Morgana]

I’ve been told by people in the youtube chat that launch is at 6 pm EST and no one knows what it’s carrying.

[alancarp]

From gizmodo:

“For its last mission, Ariane 5 will deliver two satellites to a geostationary transfer orbit, which is a path that will allow them to reach a geostationary orbit at an altitude of around 22,300 miles (35,800 kilometers) directly above Earth’s equator, using their own propulsion systems. One of the payloads is a communications satellite belonging to the German Space Agency while the other is a French military telecommunications system.”

“French company Arianespace will launch its heavy-lift launch vehicle on Wednesday during a 90-minute launch window that opens at 6:00 p.m. ET. Ariane 5 will liftoff for the last time from Europe’s Spaceport in Kourou, French Guiana...”

[God luvs America]

I don’t know- but why do the Europeans launch their rockets from South America?

[Red Badger]

Equatorial spots have a greater ‘push’ from the spin of the Earth, so it’s more economical...................

[God luvs America]

interesting

[Morgana]

NEW LINK...LAST ONE SHUT DOWN

https://www.youtube.com/watch?v=aN-ALXjcNl0

[Campion]

For most orbits, you want someplace close to the equator with ocean (to dump used rocket stages) to the east and north. Nowhere in Europe qualifies.

[verum ago]

To get into orbit, you need to get both a lot of altitude, but also a lot of speed. Both take energy.

Picture an object on the equator, and one at the north or south pole, using the earth's center as a fixed reference frame. As the earth spins on its axis, every 24 hours the object at the pole completes one slow rotation around its own center, while remaining in a fixed position relative to the earth's center. Meanwhile, over that same timespan, the object on the equator is forced to describe a circle around the earth's center equal to the earth's circumference- over 40,000 km. This comes out to around 460 m/s, or over a thousand mph.

So by launching from as close to the equator as possible, and launching in the same direction that the earth is spinning, you get up to 460 m/s of "free" velocity in the orbital direction.

For a geosynchronous orbit, that's around 15% of the needed orbital speed. Who doesn't like free stuff?

(Sorta related notes:

for achieving a geosynchronous orbit, you need to go pretty darn fast- ~3,000 m/s, and achieve a REALLY high altitude- ~ 35,000 km

for a low earth orbit, you need to go REALLY fast- ~7700 m/s, and achieve a much lower altitude- 400+ km.

The numbers work out such that for a geosynchronous orbit, about 99% of the energy goes into altitude, because those satellites are ridiculously high. But for low earth orbit, like going to the International Space Station, about 88-89% or the energy imparted to to the payload is the kinetic energy- getting into a typical orbit isn't so much about getting away from the earth's surface so much as it is about going really darn fast- so fast that as you fall, you continually overshoot the earth's surface. As a reminder, an object in orbit is in continuous free fall, that is to say it is continuously accelerating toward the earth's center. Orbit is giving yourself enough altitude cushion and going so fast that when you fall, you continuously miss the ground!)

[verum ago]

One more nerdy tidbit, as long as I'm at it:

low earth orbit isn't that much further from the earth's center than the surface (6790 km, vs 6371, an increase of only about 6.6%).

Correspondingly, to achieve orbit velocity at the earth's surface, you only have to go a few percent faster, without the hundreds of kilometers of altitude. (The catch is the drag from all the air in the way...)

[God luvs America]

Thanks- ironically i was watching a NASA video of the launch of Apollo 11 earlier today.

[Red Badger]

The ideal ‘spot’ would be on a mountaintop on the equator, with an ocean to the immediate east................

[mewzilla]

More here...

https://www.space.com/ariane-5-final-launch-webcast