|Mission type||Venus orbiter|
|Mission duration||Planned : 4 years|
|Launch mass||2,500 kg (5,500 lb)|
|Payload mass||~100 kg (220 lb)|
|Power||500 watts (0.67 hp) for payload|
|Start of mission|
|Launch date||December 2024 or mid-2026|
|Rocket||GSLV Mark II|
|Launch site||SDSC SHAR|
|Venus atmospheric probe|
|Spacecraft component||Aerobot balloon|
Funds were released in 2017 to complete preliminary studies, and solicitations for instruments have been announced. The orbiter, depending on its final configuration, would have a science payload capability of approximately 100 kilograms (220 lb) with 500 W available power. The initial elliptical orbit around Venus is expected to have 500 km (310 mi) at periapsis and 60,000 km (37,000 mi) at apoapsis.
The three broad research areas of interest for this mission include surface/subsurface stratigraphy and re-surfacing processes; second: study the atmospheric chemistry, dynamics and compositional variations, and third: study of solar irradiance and solar wind interaction with Venus ionosphere while studying the structure, composition and dynamics of the atmosphere.
Based on the success of Chandrayaan and the Mangalyaan, ISRO has been studying the feasibility of future interplanetary missions to Mars and Venus, the closest planetary neighbours to Earth. The mission concept to Venus was first presented at a Tirupati space meet in 2012. The Government of India, in its budget for 2017–18 gave the Department of Space a 23% increase. Under the space sciences section, the budget mentions provisions "for Mars Orbiter Mission II and Mission to Venus", and following the 2017–18 request for grants, it was authorized to complete preliminary studies. From 2016 to 2017, ISRO collaborated with JAXA to study the Venus atmosphere using signals from the Akatsuki in a radio occultation experiment.
On 19 April 2017, ISRO made an 'Announcement of Opportunity' (AO) seeking science payload proposals from Indian academia based on broad mission specifications. On 6 November 2018, ISRO made another 'Announcement of Opportunity' inviting payload proposals from the international scientific community. The available science payload capacity was revised to 100 kg from 175 kg mentioned in the first AO.
The space agencies of India (ISRO) and France (CNES) were holding in 2018 discussions to collaborate on this mission and jointly develop autonomous navigation and aerobraking technologies. In addition, French astrophysicist Jacques Blamont, with his experience from the Vega program, expressed his interest to U R Rao to use inflated balloons to help study the Venusian atmosphere. Just like during the Vega missions, these instrumented balloons could be deployed from an orbiter and take prolonged observations while floating in the relatively mild upper atmosphere of the planet. ISRO agreed to consider the proposal to use a balloon probe carrying 10 kilograms (22 lb) payload to study the Venusian atmosphere at 55 kilometres (34 mi) altitude.
As of late 2018, the Venus mission is in the configuration study phase and ISRO has not sought the Indian government's full approval. Somak Raychaudhury, the director of IUCAA, stated in 2019 that a drone-like probe was being considered to be a part of mission.
In an update provided to NASA's Decadal Planetary Science Committee, ISRO scientist T Maria Antonita, said that the launch is expected to take place in December 2024. She said that there is also a backup date in 2026. As of November 2020, ISRO has shortlisted 20 international proposals that include collaboration with Russia, France, Sweden and Germany. Swedish Institute of Space Physics is engaged with ISRO for Shukrayaan-1 mission.
The science payload would have a mass of 100 kg (220 lb) and would consist of instruments from India and other countries. As of December 2019[update], 16 Indian and 7 international payloads have been shortlisted. Some of them will be selected.
Astrophysicist Jacques Blamont, a former head of France’s National Center for Space Studies in Paris, several years ago proposed producing metallic balloons that could dip in and out of Venus’s hot atmosphere to study its chemistry. ISRO has adopted that idea, says Sivan, but will develop the balloon in-house. It will carry 10 kilograms of instruments and float down to 55 kilometers above the surface.
An Isro official told TOI that though it is an approved mission, the date of the launch is yet to be firmed up.
Both agencies have also agreed to conduct a joint experiment to study Venus atmosphere by collecting signals from JAXA’s Akatsuki mission by ISRO’s ground stations (IDSN).
3.6 Exploring the solar system and beyond: ISRO and CNES would work together on (i) autonomous navigation of rovers in Moon, Mars and other planets; (ii) aero braking technologies for planetary exploration; (iii) modeling of Mars and Venus atmosphere; and (iv) inflatable systems for Venus exploration. Both sides can embark on complex high technology space science and planetary exploration missions in future.