It's all about cost saving
Mission 1. Spend a substantial fortune landing a lump of scrap on a not so distant planet to prove we're cleverer than the Septics.
Mission 2. Repeat exercise and get it to drill a bloody deep hole.
Bean Counter: Can't you drill the bloody big hole on the first mission and save cost ofthe second?
Pointy headed boss: .....
BOFH: ....
I wonder if there's any quicklime at the bottom of that crater?