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Ariane 5 launch soon


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But I usually do these threads! :D

There appears to be some sort of hold.

EDIT: For those of you who know me well, I play a different cover of "The Final Countdown" at every launch I watch so thet the music synchronizes to the liftoff. Today's is one of Andrew Huang's covers (he made, like, five of them) which will synch if you start the music at T-1:29. Normally this would be T-1:36, but Ariane 5 takes off at T+7 for some reason.

Edited by Ultimate Steve
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9 hours ago, insert_name said:

both spacecraft have separated, launch success

I thought the Ariane upper stage traveled to GTO for release? 
Know falcon 9 upper don't so satellite has to do circulation burn themselves. 

And yes the upper stage reach GTO attitude but is dead at that time since battery is flat. 

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1 hour ago, magnemoe said:

I thought the Ariane upper stage traveled to GTO for release? 

I don't think any Ariane 5 mission has ever flown a direct GEO insertion. Those are typically reserved for purpose-built government spacecraft. A commercial satellite will be based on a commercial satellite bus, which has a propulsion unit of its own by default. Ergo it's just not necessary to buy a direct GEO inserting launch.

(Additionally, due to the dual launch configuration, at minimum the heavier top slot will always have to be jettisoned first, even if the light lower slot does want a direct GEO insertion.)

Edited by Streetwind
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Fun facts:

This was the 80th consecutive success for Ariane 5 overall since its last failure in 2002. For this specific variant, the ECA configuration, it was the 62nd consecutive success.

That means the Ariane 5-ECA is now up to 98.41% realized, 96.92% predicted reliability. After it flies successfully four more times, it will take over the spot of "most reliable heavy-class launch vehicle that has ever existed", which is currently still held by the retired STS (97.78%/97.08%). According to the current schedule, this may happen at the very latest in April 2018, with the launch of ESA's BepiColombo science mission.

 

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It was designed from the ground up to be human-rated at some point (which is part of why it's relatively expensive).

However, the Hermes crew shuttle program fell through, and so Ariane 5 has never actually had a crewed payload to launch and has never been formally certified as human-rated. If the currently active variants would still be able to achieve that certification, I can't say.

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1 hour ago, Streetwind said:

It was designed from the ground up to be human-rated at some point (which is part of why it's relatively expensive).

However, the Hermes crew shuttle program fell through, and so Ariane 5 has never actually had a crewed payload to launch and has never been formally certified as human-rated. If the currently active variants would still be able to achieve that certification, I can't say.

That is human rated demands for an rocket anyway? Yes see additional demands on tower and launch system, you obviously want an manned payload but that else? 

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34 minutes ago, RCgothic said:

How is 'most reliable' and 'heavy' defined in that analysis? 

As far as I'm aware Saturn 1B had 100% success.

Launch vehicle classes are determined by their payload to low Earth orbit in their default flight profile:

Small -> less than 2 metric tons
Medium -> 2 to 20 mectric tons
Heavy -> 20 to 50 metric tons
Superheavy -> over 50 metric tons

This is a semi-formal definition, existing mostly because humans in general and bureaucrats in particular like to put things into categories. It originated in the US government, but out of sheer convenience has made its way into the vocabulary of rocket people worldwide.

 

Reliability can be split into two values: the "realized rate" is simply successes divided by attempts. and gives past performance. However, that's not useful for judging how reliable a launch vehicle is if you were to put your payload onto it right now. A completely new launcher would result in a division by zero, a failed test launch would result in the worst possible score ever, a single successful test launch would result in a higher number than that of a rocket that flew 100 times but failed once.

So the more important number is the "predicted rate", which is a first level bayesian mean: successes+1 divided by attempts+2. For a launcher that has never flown, this results in 50%: it has no flight history and is therefore exactly as likely to fail as it is to succeed. This number can only climb as the rocket actually flies again and again. In order to achieve a high reliability rating, the launcher must fly a large number of times without any problems. This proves that the vehicle is inherently reliable, and did not just luck out a few times.

In case of the Saturn 1B, which flew suborbital twice, and then launched seven Apollo spacecraft:

            Successes   Attempts   Realized    Predicted
Suborbital      2           2       100.00%     75.00%
Orbital         7           7       100.00%     88.89%
Total           9           9       100.00%     90.91%

As you can see, the 1B had a flawless record, but it simply did not have the massive flight history required to play in the top leagues.

 

Edited by Streetwind
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