This is exactly how to encourage the continuing falsification of data and academic misconduct. The project head is NEVER involved in the actual writing, that's left to more junior staff. So to say "oh he didn't actually write it, even though he was the overall lead and personally responsible for the integrity of the study conducted, so we'll reward him with time on the ISS".

Not having personnel with the necessary competence to complete the study which you received significant amounts of funding to carry out is not an acceptable excuse. This is a slap in the face to anyone who values the integrity of scientists and sends a clear message to anyone who leads large studies that you can allow as much misconduct as you want so long as you don't actively participate. It's like saying that a head of a factory releasing toxic waste into the sewage isn't responsible cos they weren't the ones who turned on the taps... It's a disgrace