Aquanauts on an Asteroid Mission

NASA astronaut Dottie Metcalf-Lindenburger (white suit on the left) and ESA astronaut Timothy Peake (white suit on the right) install a large mock-up to evaluate the best ways to set up a large payload on the surface of an asteroid. In this configuration, Dottie is secured to a mini-sub simulating a space exploration vehicle, while Timothy is wearing a jetpack. Credits: NASA/ESA/Hervé Stevenin

ESA astronaut Tim Peake recently spent 12 days underwater with three other aquanauts to look at the best ways for astronauts to explore an asteroid. Behind the scenes, a large support team was learning through experience.

No effort was spared to make the experience as realistic as possible. This Neemo mission simulated a mission to an asteroid 15 million kilometers (km) from Earth, almost 39 times farther than the Moon.

At this distance, it would take a message from Earth around 50 seconds to reach the crew.

If an astronaut replied to a message from ground control immediately, people on Earth would still have to wait a minimum of 1 minute and 40 seconds before hearing the reply. Any urgent questions or interruptions are impossible.

Neemo was the first complex operation where the astronauts and mission control had to work with a time delay, so they had to learn how it affects communications.

ESA’s Hervé Stevenin has years of experience as crew communicator for the International Space Station and was invited to be a capcom for Neemo: “On the Station, when we talk to astronauts the reply is instantaneous.

ESA’s Hervé Stevenin, capcom for Neemo. Credits: ESA/NASA

“With Neemo, we had to completely rethink communications – we were listening to the past and talking to the future at the same time.”

Underwater chatting through time

The mission controllers quickly found ways to work with the communication delay. First of all, stopwatches reminded them when to expect a reply from the underwater astronauts.

Then it became obvious that some voice messages should be announced. Hervé explains, “We introduced important messages by announcing the addressee and subject.

“For example, ‘Aquarius, MCC [Mission Control Centre], on Space to Ground One, incoming message in 10 seconds for Tim and geophysical array deployment.’” The pause gave the aquanauts time to stop what they were doing and pay attention. This avoided repeating messages, which could delay work for three minutes or more.

Finally, a new communication system was tested. Many non-urgent messages were sent through a text chat programme that allowed multiple chats at the same time, similar to chat programmes on the Internet. Astronauts could read messages and reply in their own time.

Text chat: best for an asteroid mission

The underwater Neemo base is almost 20 m under the sea off the coast of Florida. Credits: ESA–H. Stevenin

Hervé adds: “We found that text chat is the most appropriate communication system for an asteroid mission, accompanied by voice messages to keep a human touch.

“If a voice message is complex, texting the same message as well is very helpful.”

This Neemo mission was one of the most complex underwater simulations ever conducted. More than 80 engineers, divers and others worked 14-hour days to support the aquanauts from NASA’s mobile mission control, boats anchored above the Aquarius base, and even from submersibles.

In addition to communication duties, Hervé supported Neemo as a scuba diver: “Being a Neemo working diver helped capcoms to understand the constraints and challenges of the environment in which the aquanauts were working.”