In fact, I've completed almost all the ships on 100% with all the contracts done and I can assure you, it's possible. Other than some flying parts which I took care of with the dynamite and ocasional tool bugs which were minor incidents easily fixable during the gameplay without even loading the game I've not enocountered a lack of resources to complete contracts. Simply collect everything, don't lose the heavy objects and you'd be fine. I'm sorry to hear you have problem with completing all the contracts but other than accidentaly destroying some parts which were necessary to complete the tasks I don't know what could've happened... Perhaps your ship didn't load in it's entirety but it's a very, very rare occurance and you just have to load the autosave after scraping your last ship and buy the new one again.