A challenging ordeal, filled with frustration, setbacks and even failure is an important step in the rite of passage.
Failure is just an opportunity to learn and grow, and this is practically imbibed in the youngsters in the tasks undertaken while ensuring that the focus on the positive aspects.
Some points to ensure:
Record and bring forth the lessons from the project activity by making the students aware of the many details they can miss due to their focus on their performance.
Keep the 'wonder' part alive and do not let go of ethics and morals in this exercise.