Background
Latency is the delay between a signal being transmitted and received. Technology now allows us to communicate over much greater distances. The signals in voice and data networks are typically transmitted as light over fibre optic cables. They travel much faster than the speed of sound. In fact they travel so fast that latency, even when transmitting to the other side of Earth, is negligible.
However, in space, distances to Earth can be so vast that, even with signals that travel at the speed of light, latency becomes noticeable very quickly. The moon is nearly 400,000km from Earth. At that distance the delay is about 1.3 seconds one way. As we go deeper into space, the distance to Earth gets larger, the delay grows and a “normal” conversation between space crews and people on Earth soon becomes difficult.
The distance to the moon does not change much as the moon orbits the Earth in almost a perfect circle. The distance to Mars varies a lot, as both planets separately orbit the sun. At closest approach the distance is about 55 million km. And at its most distant it is almost 400 million km away from Earth. That means the one way latency for communication with a future crew on the surface of Mars will have a minimum latency of just over 3 minutes and a maximum of over 22 minutes.
Our bodies and nervous system in particular have evolved to expect access to real time communication. Whilst a future crew on Mars will be able to talk to each other normally they will not be able to talk in the same way with loved ones on Earth.
To learn more, visit Braided Communications Website.
The experiment at MDRS
WoMars has made the decision that their analog mission will adopt a ‘high fidelity to Martian conditions’ approach during their MDRS mission. This means that, except for any emergency situations, all communication between the habitat and “Earth” will be subject to a 5 minute one way time delay. That is the same as a separation of 90 million km. Within that environment the crew will conduct a number of tests and activities that may provide valuable insights for future deep space missions. In particular the crew will compare the effectiveness of two communication tools that are designed for use in high latency situations. One of these tools, Latency Governed Messaging (LGM), is similar to the tool that has been adopted in previous similar research experiments in other analogs that have operated under time delay. The other, Space Braiding, is a novel tool also designed specifically for high latency environments. Both these tools have been designed and developed by Braided Communications Ltd.
Due to the 5 minute one way time delay there will be no ‘normal’ two way voice communication between the crew and “Earth.” The crew will use LGM and/or Space Braiding for all external communication. The experiment WoMars will be conducting during the Nerio I mission is the first known attempt to measure the impact of a “Mars type” latency on personal communication with contacts “on Earth.”