Engine Dormancy and the Turbopump Challenge in Crewed Mars Descent
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Paul Almond
jbis-078-09-0315
DOI https://doi.org/10.59332/jbis-078-09-0315
Turbopump-fed cryogenic engines for Mars landings face a key reliability challenge: prolonged dormancy during interplanetary cruise, combining long inactivity with vacuum exposure and repeated thermal cycling. Turbopumps are mechanically complex, reliant on seals, valves, and cryogenic plumbing, and are more vulnerable to timerelated degradation than simpler pressure-fed designs. Because one engine type will likely serve across multiple missions, a single dormant engine flaw could propagate through an entire Mars fleet. Unlike the short-mission Apollo lunar descent engines, future vehicles such as SpaceX’s Starship may depend on turbopumpfed engines that sit inactive for months before reigniting for critical descent burns. This paper examines systemic risks from such dormancy – including seal shrinkage, valve stiction, lubricant migration, and thermal cycling fatigue – and how they could undermine redundancy across a vehicle class. While stochastic hazards such as micrometeorite strikes are noted, the focus is on dormant engine failure modes that scale. The paper argues that systemic risks are solvable once characterised and recommends extended ground and orbital soak tests to reduce dormancyrelated ignition failures before crewed Mars missions, recognising that opportunities to generate statistically robust datasets will be inherently limited.
Keywords: Mars Landing, Turbopump Dormancy, Cryogenic Propulsion, Systemic Risk, Engine Redundancy, SpaceX Starship
