Keeping Mars talking: a week of Polaris relay servicing at Phobos

If you have ever sent a message from Olympus Ring to Earth, it probably passed through a relay satellite that a Polaris Relay Tender has serviced. Mars depends on about forty relays in orbit around the planet and its moons, and without regular maintenance the network would degrade within a few years.

I spent a week with one of our partner crews based at Phobos. The Polaris is an 88-metre tender flown by two pilots, with five technicians operating its twin robotic arms. It moves on xenon ion propulsion, using just 1.4 tonnes per 100 AU, which lets it hop between relays in different orbits for weeks without refuelling.

The schedule was ambitious: six relays in seven days. Each visit followed the same rhythm. Rendezvous, approach to 30 metres, capture with the primary arm, then refuel, swap the degraded modules and run diagnostics. The secondary arm handles tools and spare parts drawn from the tender's 320-tonne cargo bay.

Day four was the hard one. A relay in high Mars orbit had a jammed solar array and a failed attitude control unit. The crew replaced the unit, freed the array with a custom tool printed on board, and returned the relay to service in nine hours. Before servicing tenders existed, that relay would have been abandoned and replaced at a cost of about 40 million credits.

That arithmetic is why our partners buy Polaris tenders. At 118 million credits, a single tender pays for itself after saving three relays. The partner I visited estimates their two tenders saved the Mars network more than 600 million credits in replacement costs over the last five years.

The crew live aboard for rotations of about ten weeks, with a handover at the Phobos depot. Their habitat is compact but well designed, with a small observation cupola that looks straight down at Mars. One technician told me she has watched more than 300 Martian sunrises from that window, and still stops work to look at every one. Good crews love their ships, and it shows in how they care for the satellites they service.

What impressed me most was the crew's care. They treat each relay as a patient. Every repair is logged, photographed and shared with the satellite's owner. Quiet, careful work, and the reason Mars keeps talking.