With a surface hot enough to melt lead, broken atmospheric pressure and clouds of sulfuric acid, Venus might not sound like the most appealing destination for human exploration.
But a group of experts is advocating that our second-closest neighbor, not Mars, should be the initial target for a manned mission to another planet.
There are significant drawbacks. Walking on the surface would be an unbearable experience, so astronauts would have to observe the planet from the safety of their spacecraft on a flyby mission.
In its favor, however, Venus is significantly closer, making a return mission feasible in a year, compared to a potential three-year return trip to Mars. The flyby would be scientifically valuable and could provide a key experience of a long-duration deep space mission as a precursor to a visit to Mars, according to a report presented at the International Astronautical Congress (IAC) in Paris last week.
“Venus gets a bad rap because it has such a harsh surface environment,” said Dr. Noam Isenberg of the Johns Hopkins University Applied Physics Laboratory and one of the proponents of the Venus flyby.
“NASA’s current paradigm is from the moon to Mars.” “We are trying to list Venus as an additional target along the way,” he said.
Isenberg said there are practical arguments for including a Venus flyby in the manned Mars landing that NASA hopes to achieve by the late 2030s. Even though the planet is in the “wrong” direction, performing a slingshot around Venus – known as a gravity assist – could reduce the travel time and fuel needed to reach the red planet. That would make a manned trip to Venus a natural stepping stone to NASA’s ultimate goal.
“You would be learning about how humans work in deep space without committing to a full mission to Mars,” he said. “And it’s not just about going to the middle of nowhere – that would have some objections because you’d be visiting another planet for the first time.”
“We need to understand how to get out of the cradle and into the universe,” he added.
There is also renewed scientific interest in Venus. The discovery of thousands of exoplanets raises the question of how many could be habitable, and scientists want to understand how and why Venus, a planet so similar to ours in size, mass and distance from the Sun, ended up in hellish surface conditions.
Isenberg said the Venus flyby “doesn’t have traction yet” in the wider space travel community, although there are advocates within NASA, including its chief economist Alexander MacDonald, who chaired the IAC session.
The two recently co-edited a report titled Encounter with the Goddess that justifies the hypothetical mission, suggesting that astronauts could deploy tele-operated rovers, drones and balloons to observe Venus’ active volcanoes and look for signs of past water and ancient life.
“There is every reason to believe that Venus will be an endless wonderland of enchanting and mysterious sights and formations,” the report said.
However, not everyone is convinced by the concept. “It’s really not a nice place to go.” It’s a hellish environment and the thermal challenges for a human mission would be quite great,” said Professor Andrew Coates, a space scientist at UCL’s Mullard Space Science Laboratory.
He said that Venus was rightly the focus of scientific research, but that “a human flyby really wouldn’t add much.”