Indian mission to Venus, - proposed! Options

[Phil Stooke]

Interesting news item from The Asian Age:

http://www.asianage.com/india/after-mars-i...e-2-3-years-335

Quick summary - looks like it's only a feasibility study, so I don't know how far it has gone along the planning and proposal process. But the veteran French planetary balloon proponent Jacques Blamont has been working with Indians on the plans, and one or more balloons in the atmosphere are part of the mission plan.

Phil

[vjkane]

Just came across this tidbit from a presentation to the Planetary Science Advisory Committee summarizing the status of the proposed ESA/NASA EnVision mission (NASA would provide some or all of the SAR instrument). The spacecraft would carry three instruments plus radio science. Here's it's coverage of Venus after it's prime mission:

78 Tbit data return in 4-cycle, with >60% IR and sounder coverage, >15% InSAR and polarimetry coverage (30 m resolution), and 2% high resolution (~2 m resolution)

VEXAG updata

[JRehling]

Lest there be any doubt, the planned orbit is highly elliptical: peri=500km, apo=60,000km. That is very similar to Venus Express' orbit, has about the same apoapsis as Venera 15/16 and Pioneer Venus and similar to the planned orbit for Akatskui (the actual apoapsis ended up much more remote). For what it's worth, Mariner 9's apoaspsis at Mars was 16,860 km while Mars Express' is 10,107 km.

Circularizing the orbit on a mission like this is costly and that ends up being paid somehow in mass and complexity. This high instrument count is part of a tradeoff for the elliptical orbit. It means that coverage will not be so complete in time (atmosphere) or space (surface), but given the novelty and diversity of the instruments, it's a pretty good tradeoff. Magellan is the only Venus orbiter that's had a circular orbit, which is ideal for surface instruments, but Shukrayaan-1 is poised to give us great new surface science that will cover a lot of the surface (probably the low latitudes) at high resolution and leave us hungry for a future mission to cover the rest. If it succeeds, it may shift the balance of Venus science goals to surface missions rather than incremental gains from orbit.