During February 2018, the Austrian Space Forum conducted the AMADEE-18 Mars simulation in the Dhofar desert region, Oman, and we were part of it! A Tumbleweed prototype with a diameter of 2.25 m was tested three times. Our solar cells worked, and we were able to prove the functionality of our “emergency brake” system that stops the Tumbleweed when it approaches no-access zones as defined by planetary protection. Unfortunately, several parts spontaneously disintegrated (meaning: they broke). We had no aluminum and titanium parts at the time, so we were forced to print alternative, more massive designs from ABS and PLA plastics. The broken parts also showed us where our designs have to endure the most mechanical stresses, which we incorporated into our new designs.