Is the timing right?
Envision as an enabler of future explorationVenus Express launched in 2005 and retired in 2014 by burning up in the atmosphere. This date began a period where no spacecraft will be in orbit around Venus. The M5 launch bid is a needed opportunity to continue monitoring of processes at Venus to enable correlations with previous data. Results from Venus Express show a dynamic and changing world on timescales of just a few years.
High altitude winds:
Interpretations varry and many hypotheses try to explain this phenomenon. The rotation period of the planet is also changing, it is not excluded there could be angular momentum exchange between the planet and the thick atmosphere. EnVision will yield new clues into the coupling between the surface and atmosphere.
Amongst the Venus scientific community, an InSAR mission is widely regarded as an enabler to future missions. These future plans include a long lived surface exploration or buoyant balloons. Indeed, EnVision will significantly increase our global understanding of the planet and its history. It will actually put the landing sites of the previous landers into context, yielding new science from these past missions. For future landers, it will aid precise landing site selection based on geophysical interests rather than just orbital mechanics considerations.
Be sure to check out the VEXAG (Venus EXploration Analysis Group) recommendations and future scope as well as the EVE proposal on the Resources page.