NEW DELHI—The Indian Space Research Organisation (ISRO) in Bengaluru will send an orbiter to Venus in 2023 and has invited scientists from around the world to submit proposals for instruments to carry along. The plan, which will include a balloon dropped into the planet’s atmosphere, has received a warm welcome from Venus scientists, many of whom feel that, compared with the moon and Mars, their planet has received short shrift in the past 2 decades.
The as-yet-unnamed spacecraft is likely to weigh 2500 kilograms and may have a 100-kilogram payload; it will be launched on India’s heaviest rocket, the Geosynchronous Satellite Launch Vehicle Mark III. The orbiter will initially be placed in a large elliptical orbit around Venus that is gradually shrunk.
Like Earth, Venus is some 4.5 billion years old; the planets are of similar size and mass. But Venus has witnessed a runaway greenhouse phenomenon, leading to a dense, carbon dioxide–rich atmosphere that may offer scientists clues about the development of Earth’s atmosphere. “Planetary comparative climatology is an area of continued interest and research. The opportunity to explore Venus together is welcome,” says Lori Glaze, acting head of NASA’s planetary science division in Washington, D.C.
Venus is a hostile planet to study: Its thick clouds make research from an orbiter difficult, while heat, high pressure, and sulfuric acid droplets make descending to the surface a technological nightmare. Of the more than 40 Venus missions so far, roughly half have failed, and only a handful spacecraft have touched down on the planet’s surface.
That’s why the crowd gathered at a meeting of NASA’s Venus Exploration Analysis Group in Laurel, Maryland, was “very excited” to hear India’s call for collaboration on 6 November, says Patrick McGovern of the Lunar and Planetary Institute in Houston, Texas. “In the absence of new Venus missions and data, it is increasingly difficult to generate support for students and early-career researchers interested in Venus,” he says. That keeps the Venus community small, which “in turn affects the ability to rally support for new missions,” McGovern says. “In my view we are presently at the reconnaissance stage of [Venus] exploration, equivalent to that of pre-1997 Mars.”
ISRO has already selected 12 instruments, proposed by Indian scientists, including cameras and chemical analyzers to study the atmosphere. Now, it’s hoping other scientists will join. “Planetary exploration should be all about global partnerships,” says Kailasavadivoo Sivan, a rocket scientist and ISRO’s chair. (The deadline for submitting proposals is 20 December.)
McGovern hopes to send a radar instrument that could penetrate the thick clouds and make sharper maps of the surface, which could help address questions remaining after NASA’s 1989 Magellan mission to Venus. Planetary scientist Larry Esposito of the University of Colorado in Boulder says he’d like to contribute instruments that would study the planet’s atmosphere. He’s particularly interested in Venus’s clouds and how they could be responding to possible ongoing volcanic eruptions. “The past ISRO missions provide confidence,” Esposito says. (India visited the moon in 2008 and Mars in 2014; it has another moon mission scheduled next year and a new visit to Mars in 2022.)
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.
