Ariane 5 launched yesterday, very nice nightime video with clear boosters sep.

[H2O.]

Those guys make things looks easy.

[SpaceplaneAddict]

I always love a good rocket launch.

[Tex Mechs Robot]

watched this live at work. it was one of the better broadcasts i've seen with graphical telemetry, beautiful real shots, and excellent commentary.

[hugix]

Wow, check that fairing wobble after release!

[Tex Mechs Robot]

Wow, check that fairing wobble after release!

And to think they weighed 2 tons. They look like they're made out of plastic!

[Thegamer211]

And to think they weighed 2 tons. They look like they're made out of plastic!

Yeah! Are they supposed to wobble like that?

If yes, why are they so weak and how do they survive ascent?

[Tex Mechs Robot]

Yeah! Are they supposed to wobble like that?

If yes, why are they so weak and how do they survive ascent?

They are engineered perfectly to be just strong enough to withstand launch forces while minimizing weight. In fact, the flexibility actually assists with withstanding the forces as rigid structures are more brittle.

[H2O.]

Yeah! Are they supposed to wobble like that?

Yes they are. If I recall correctly this phenomenon is called "breathing".

They are not weak but just strong enough to be rigid while attached, not when jettisoned.

[FishInferno]

One thing that always puzzled me about the ariane launches is that they ignite the engine after reaching T: 0, instead of starting them a couple seconds early like most other rockets.

[Kryten]

One thing that always puzzled me about the ariane launches is that they ignite the engine after reaching T: 0, instead of starting them a couple seconds early like most other rockets.

It's just a different definition of what T:0 actually is; as first ignition rather than takeoff.

[H2O.]

they ignite the engine after reaching T: 0

Ariane 5 has a BIG main stage. It goes from 0 m/s to almost orbital velocity. My belief is that this stage is such an important part of the rocket that it make sense to countdown from the moment you start it, rather than lift-off.

[Hcube]

Yes they are. If I recall correctly this phenomenon is called "breathing".

They are not weak but just strong enough to be rigid while attached, not when jettisoned.

Yup, that's what it's called (at least in France for Ariane, don't know for other rockets/countries) !

It's pretty cool. I wish that was in KSP instead of the frag grenade sep.

Btw that was the last Ariane 5 launch of 2015

[H2O.]

Yes, but there will be a Vega and a Soyouz launch before the end of the year in Kourou. Busy year!

[Hcube]

Yes, but there will be a Vega and a Soyouz launch before the end of the year in Kourou. Busy year!

I always looking forward to Vega launches, they're awesome and there's so few of them !

I feel like that soyuz version they launch looks kinda weird with that huge fairing though

[Kerbal01]

Did this Ariane have live rocketcams? This is the first time I've seen the views from the booster of SRM and fairing step, and this is the 5th Ariane V I've watched launch.

[Jovus]

Wow, the TWR right off the pad is impressive! Looks something like a 1.6-1.8

Also, amusing slip on the part of the English announcer: you need ~9.5km/s to reach orbital velocity, but orbital velocity itself is ~7.8km/s

I was also surprised at exactly how high the altitude is where fairing separation occurs. I wonder why?

[Streetwind]

Did this Ariane have live rocketcams? This is the first time I've seen the views from the booster of SRM and fairing step, and this is the 5th Ariane V I've watched launch.

Ariane almost never has live rocketcams. That is, the cameras are there, but the feed isn't broadcasted live. This one didn't broadcast either.

I'm actually surprised that you never saw those shots before, because both the video from the booster separation and the video from the fairing separation are both from an earlier launch. They play these exact same two archive clips every single launch The announcer usually mentions that it's archive footage, but this time he didn't for some reason. You can still easily see that it wasn't from this launch though, because it was deepest night during launch but the video showed things in sunlight.

[Bev7787]

Second Ariane 5 flight vid I've seen. Last one was an archived one of the Ariane 5 that launched Rosetta.

[ment18]

Wow, the TWR right off the pad is impressive! Looks something like a 1.6-1.8

Also, amusing slip on the part of the English announcer: you need ~9.5km/s to reach orbital velocity, but orbital velocity itself is ~7.8km/s

I was also surprised at exactly how high the altitude is where fairing separation occurs. I wonder why?

It is 9-10km/s into LEO when you include drag and gravity losses I think. Kerbin orbital velocity is about 2km/s but is takes like 3.5km/s to orbit

[Hcube]

Wow, the TWR right off the pad is impressive! Looks something like a 1.6-1.8

Also, amusing slip on the part of the English announcer: you need ~9.5km/s to reach orbital velocity, but orbital velocity itself is ~7.8km/s

I was also surprised at exactly how high the altitude is where fairing separation occurs. I wonder why?

It's close to 1.83 and varies with the payload iirc ^^

I guess the fairing sep is late to prevent contact between air and the payload

[WinkAllKerb'']

thks for sharing H2O

Edited November 12, 2015 by WinkAllKerb''
also that launch at night vids kinda interesting to higllight some stuff ; )

[Gaarst]

Orbital velocity in LEO is about 7.7 km/s and you need around 9km/s of dV to get in LEO.

But keep in mind that Ariane 5 is designed to put payloads in GEO, without circularising LEO first: and as it turns out, the orbital velocity at LEO altitude for GEO insertion is about 9-10 km/s.