I have somehow missed one of the spaceship parts, I got as far as number 22 on a list when I noticed that it said 21/50. I remember successfully finding every single one of the first 22 parts on the list, so I can only assume I lost one through dying or through quitting without saving. I have gone back over all 22 of them and cannot find any that I missed though! Is there any way that I can reset the mission and start again, so I can keep track of the "n/50" notifications to make sure I get them all?