EnVision is an ESA-led mission to Venus, developed in partnership with NASA that provides the synthetic aperture radar (SAR). It was selected in 2021 as the fifth M-class mission of ESA’s Cosmic Vision Science Programme. Its main objective is to study the planet from its inner core to the upper atmosphere to determine how and why Venus and Earth evolved so differently. To achieve this goal, it will carry a suite of scientific instruments, including: a dual polarization reflectarray S-band SAR; three spectrometers designed to observe the surface and atmosphere of Venus in IR and UV bands; a radar sounder instrument in HF frequency range to penetrate the subsurface; as well as a radio science experiment.
 
EnVision is set for launch in November 2031 by an Ariane 64 rocket for a direct injection into an Earth-escape trajectory. The backup launch period takes place in December 2032, and beyond 2032 there exist feasible opportunities in 2033, 2034 and 2036. The baseline interplanetary transfer consists of a 1-year Earth-to-Earth arc that includes up to two deep space manoeuvres, an Earth swingby in November 2032 that rotates the V-infinity vector to the one required for a type-2 transfer, which arrives at Venus in May 2033.
 
Upon arrival to the target planet, the critical Venus Orbit Insertion (VOI) manoeuvre is performed with the 1-kN main engine to inject the spacecraft in a bound orbit around Venus. As EnVision’s scientific objectives require a quasi-polar orbit for science operations, there are two possibilities for the selection of the B-plane impact point during the Venus approach: either over the North or the South pole, which determines the right ascension of ascending node as well as the argument of pericentre. The option resulting in a higher latitude at pericentre is selected in order to limit the eclipse durations. Afterwards, a sequence of apocenter lowering manoeuvres is executed to shorten the duration of the aerobraking phase.
 
During aerobraking operations, the pericentre altitude is lowered, and controlled, such that the
spacecraft dips into the atmosphere with the solar panels oriented against the atmospheric flow to maximize aerodynamic drag force while respecting the S/C aerothermal limits. Thousands of aerobraking passes are required to reach the required apocentre altitude for the science orbit, resulting in mission-enabling propellant savings.
 
The science phase is planned for a nominal duration of 6 Venus cycles, i.e. approximately four (Earth) years, in a quasi-polar orbit with altitudes over the planet’s surface ranging from 220 to 510 km. It is planned to perform small orbit phase control manoeuvres every 4 weeks to ensure synchronization with the reference trajectory used for science operations planning, as well as relatively bigger orbit maintenance manoeuvres once per Venus cycle to keep the orbit altitude within the target range.
 
This paper is dedicated to the end-to-end EnVision Mission Analysis aspects, focusing mainly on trajectory analysis and design: launch scenarios, Earth-Venus transfers, Venus orbit insertion, apocentre lowering sequence, aerobraking operations, and science orbit selection. Finally, the current mission baseline is described, as a result of the relevant trade-off analyses and applicable mission constraints.