Analysis of information sources in references of the Wikipedia article "Philae (spacecraft)" in English language version.
The other options, including a launch to Wirtanen in 2004, would have required a more powerful launch vehicle, either an Ariane 5 ECA or a Proton.
The other options, including a launch to Wirtanen in 2004, would have required a more powerful launch vehicle, either an Ariane 5 ECA or a Proton.