ariane

The management of the Ariane program decided that the unit was going to be used in Ariane 5 as well, without certifying it for the new rocket.

You know that the Ariane 5 rocket crashed (and could have killed people!) because of an int overflow?

This was never discovered, because the trajectory of the Ariane 5 was never tested with the code.

The Ariane 5 rocket is much more powerful, and will get much further in the trajectory than Ariane 4 in that time, so an angle big enough to get overflow will happen.

International Space Station couldn't be build using Atlas and Delta, Proton and Ariane alone - especially after Mir was built by Protons?

As far as I know there's no technical reason Ariane 5 couldn't be used for them right now.

The resulting confusion could equally destroy the engines; this is similar to what happened to the Ariane 5 rocket that caused it to explode.

I have no idea if its possible to retro-fit man-rated safety onto the existing Ariane design.

The Ariane 5 failure is a little more nuanced than that though.

We had to write an essay about Ariane V failure.

And about that Ariane incident, you're also right.

Minor correction: Ariane -> ESA (European Space Agency).

The conversion bug was in the Ariane 4 too, they reused the IRS, so it was almost "proven in use" but Ariane 5's trajectories put it under much higher acceleration (enough to trigger overflow).

It does not make sense in every situation to do a range check and return an error, or worse, "panic" (the latter didn't work for the Ariane 5).

Ariane 5 (with 77 flights and 2 full and 2 partial failures--all at the early stages of the program) ain't bad either.

Ariane is the name of the rocket (and 'Arianespace' the name of the company that does the actual launching for ESA, but that's just part of ESA with a different name).

Looking quickly at a random handful of currently operating Eutelsat satellites, two launched by Ariane, one by Zenit (Russian/American/Norwegian/Ukranian), one by Proton (Russian), one by Atlas V (American).