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Or in this case every 1/100th of a second counts. Tomorrow's launch is set for 05:03:04 CET - precisely. Its this kind of timing that makes all the difference. As you can see in Daniel's posting of the ascent timeline, the timing continues with this kind of accuracy, with each critical event needing to be timed perfectly...
(click on Full story for more)
Just think about it. Get your timing wrong - just .01 of a second too late - and you've left the upper stage firing for longer than needed and, with the amount of thrust involved, you'll have overshot your mark. .01 of a second too early, and Jules Verne ATV isn't going to reach its initial 260 km orbit.
For this reason, the launch and each critical event thereafter has to be timed right down to the last hundredth of a second, putting Jules Verne ATV in the right orbit and safely on its way to the International Space Station.
--Maria
Launch countdown
08 March, 2008 19:49
5 comments | "Every second counts"
08-03-2008 • 20:10:32
Please check this story again. The launch is at 05 hours, 03 minutes and 04 seconds. This is not to 1/100 of a second. I know the launch window is critical, and I am not an expert on this, but to launch on the second is probably enough to reach the correct orbit.
08-03-2008 • 20:15:33
I don't want to be a nitpicker, but I think the launch time and timeline events are accurate to one second, instead of 1/100th of a second.
08-03-2008 • 20:27:40
Hi Oliver, Michiel,
Ah.. fuzzy mind here. Glad someone is awake. Indeed :04 isn't one hundredth - I've taken the liberty of rewording a little. On this post, Alberto Novelli said: ""you can use it even though for us we count the precision along x axis in seconds >> TDRSS aquisition" - which goes beyond me. So yes, this post does put it very simply, but I think it illustrates a point. Doesn't it? --Maria
08-03-2008 • 20:51:14
Does ESA/Arianespace operate a slightly different count to NASA for example where the first stage engine is started at the '0' count and the boosters are ignited for liftoff a couple of seconds later?
It's just something I dragged back from memory of watching an Ariane 5 launch and feeling momentarily confused that it 'hadn't gone yet'.
08-03-2008 • 20:59:53
Hmmmm.. I'm not sure in comparison to NASA. I do know that the Ariane timeline shows 05:03 CET - Main engine start - Ariane 5 Vulcain engine/EPC ignition, followed by solid boosters ignition and lift-off at +00:00:07, i.e. 7 seconds later. See: http://webservices.esa.int/blog/post/1/74
-- Daniel