Questions on carriers in combat and intel

I am playing a game where I had a planet with 50 ships and a carrier orbiting with 1 ship. I got attacked and the carrier with its 1 ship got destroyed first before the planet ships destroyed the attacker. Is there anything I’m doing wrong here? I thought I read a garrison would fight an attacker first. Is the only way to save the carrier to either transfer enough planet ships to the carrier or move the carrier before the fight takes place? No way to force the planet ships to defend first?

Next question - is there any way to see other players’ credits, research points (not level), or what they’re currently researching?

You can’t see private information, the best you can do for research is to take note of exactly when they build new Science and when they get upgrades and math out exactly how long researching a specific tech would take them. This can potentially be very useful early game when determining when the enemy will get Weapons 2 or 3. But after a few days it just becomes too variable because of Experimentation and trading to do with reliability.