Scientists want to string satellites through space to communicate with other worlds

Andrew Griffin
Fri, 24 February 2023 

(Getty Images)

Scientists hope string satellites through space so that we can more easily communicate with other worlds.

The concept, inspired by the “Pony Express” that used messages relayed by riders on horses to cross the US. It operated for just 18 months around 1860 – before it was overtaken by the telegraph – but may live on in an entirely new form, researchers hope.

In the Earth-bound polar express, letters were sent between stations that would relay messages. The Solar System Pony Express, or SSPE, would use much the same system, except with satellites flying back and forth in space.

That could allow for much better communication with the spacecraft that are travelling through the solar system, exploring other worlds such as Mars and beyond.

At the moment, such communications rely on the Deep Space Network, a set of ground-based equipment that can send messages out to Nasa’s spacecraft. But that network is limited, both in terms of speed and how much data can be carried at once.

Scientists hope that the SSPE could help that system become faster and more capable. It would work by sending “data mules”, that are made up of small spacecraft and can travel somewhere such as Mars, passing on messages.

“The Solar System Pony Express is a mission concept that aims to augment the data transmission capabilities of the Deep Space Network using the idea of data mules,” said Robyn Woollands, from the University of Illinois Urbana-Champaign, one of the authors of the new paper.

The mules would arrive at Mars and sit close to a probe’s transmitter. They would then carry the data back to Earth, where it could be sent back to a receiver.

Using low-thrust propulsion and the gravity of the Sun, Earth and Mars, the spacecraft would be able to travel around in space without using large amounts of resources, scientists suggest.

That is partly because of the development of ion engines, which are more efficient than widely-used chemical engines, and are light enough that they can be launched more cheaply.

“Our study revealed that the total data volume returned during the simulated mission exceeded our goal of 1 Petabit per year,” said Alex Pascarella, Robyn Woollands’ PhD student, in a statement.

The idea is detailed in a new paper, ‘Low-thrust trajectory optimization for the solar system pony express’, published in the journal Acta Astronautica.