Progress MS-35 (96P)

Progress MS-35 is the ninety-sixth Progress to fly to the Station — a streak that started in 1978 with the original Salyut 6 station and never paused for more than a few months. The freighter lifts off from pad 31/6 at Baikonur on a Soyuz 2.1a, reaches orbit in nine minutes, and docks to the Zvezda module two days later under fully autonomous Kurs-NA guidance. About 2,500 kg of food, water, propellant and spare parts. Russian engineering at its most matter-of-fact.

The interesting cargo on a Progress flight is rarely the food. It is the fuel: roughly 870 kg of unsymmetrical dimethylhydrazine and nitrogen tetroxide that, once docked, gets fed through valves into the Station’s own propellant tanks. That fuel is what raises the orbit every six weeks against atmospheric drag, and what eventually steers the Station to its disposal over the southern Pacific at the end of its life.