You have to destroy the sentinels orbiting the artifact before you can collect it - which might be tricky because you don't want to shoot the artifact, and those sentinels have the ability to respawn as long as one of 'em is still in business.
The first galaxies are rather easy, but believe me, it does get harder if you progress - and yes, the bounty does also increase. And don't forget, all the money you spend, will be back with you in the next live.