Missed Thrust Events
From ionizing radiation to micrometeoroids, space is a dangerous place. Most spacecraft, when they feel threatened, can autonomously enter into a protective operating mode call safe mode. Different spacecraft do different things in safe mode, but most turn off all non-essential components, like propulsion and the payload, to focus all energy on trying to communicate with earth, and if it has solar panels, keeping them pointed towards the sun. One system that is often considered non-essential is propulsion, and if a safe mode event happens during a thrusting arc, it starts a missed thrust event (MTE). A new generation of spacecraft want to take advantage of highly efficient propulsion systems, like electric propulsion and solar sails, which are more susceptible to these MTEs. Unlike traditional propulsion methods, which can produce a large amount of thrust in a short period of time, these high-efficiency engines can only offer fractions of traditional engines thrust. This means that instead of a burn taking minutes to hours, these engines will need to thrust continuously for weeks to months at a time. For a planetary rendezvous, these engines may even need to thrust continuously for the entirety of a trajectory. Low-thrust interplanetary trajectories are often years long, and a spacecraft has a 60% likelihood of entering a safe mode after 200 days
Number of Days In Thrust Arc:
