What stability concern does Scott Hubbard raise regarding Starship's tall, slender vehicle profile during vertical propulsive landing?

Risk of tipping or catastrophic loss if stability is not precisely maintained

Scott Hubbard, a former NASA director, points out a significant aerodynamic and structural risk associated with Starship's vertical propulsive landing technique. Unlike previous landers that were inherently squat with low centers of gravity, often utilizing airbags or parachutes to aid stability upon impact, Starship is described as a tall, slender vehicle. This configuration demands extreme precision in the final moments of landing thrust vectoring. Hubbard references potential failure modes, such as the Odysseus lander tipping over on the Moon due to an altimeter malfunction, as an analogy for the catastrophic risk inherent in a precise vertical landing onto an unprepared Martian surface where slight deviations in orientation or descent rate could lead to the vehicle failing to remain upright and consequently being lost.