Months of preparation will come down to a few hours of intensive work tomorrow.
Weather and technical conditions permitting, an unmanned booster rocket carrying an automated transfer vehicle (ATV) will blast off from the ESA's International Space Port at Kourou, French Guiana, just before 10am New Zealand time.
About an hour later, when the booster and its payload are about 300km above the earth, the launcher should separate from the ATV - right above Awarua.
It will be a short, once-only journey for the multimillion-dollar booster. Moments after the separation, rockets will be fired at it to ensure it tumbles back into the earth's atmosphere and burns up.
The ATV will carry on to the International Space Station with more than seven tonnes of equipment, water, air and food. It will also carry fuel and once docked to the station - which it achieves automatically with an accuracy of 1.5cm - will be fired up to push the station further into space so it can maintain its orbit.
Mr Steenkamp and Mr Korkie will track the craft to record the separation and the booster tumbling back to Earth. They will send their data to Mr Sonny, who will stay in touch with two ESA control centres.
The separation and deorbiting will be all over in about 10 minutes, but the technicians will also have to track the booster's second pass later in the day.
They have spent many hours calibrating their equipment and carrying out "dress rehearsals" by test-tracking commercial satellites.
Tomorrow, their day will start about 2am with several simulations of the booster's planned trajectory. Their station has mains electricity but they will switch to a generator in case of a power cut.
"There is no second chance," Mr Korkie said.
The Awarua station is one of six across the globe which will track the launch.
Telemetry is the science and technology of automatic measurement and the sending of data by wire, radio, or electronic means from remote sources.
For Mr Steenkamp and Mr Korkie, 20-year telemetry veterans, tracking space craft is a "sideshow" to their main job - collecting data from flights at the Danel Overberg aircraft and weapons systems testing facility in South Africa.
Since 2000, their spacecraft tracking work has taken them to several locations including Namibia and Ghana.
They first came to Southland in 2007 when the Awarua tracking station was being set up and have returned almost every year since to track an ATV launch.
They said they enjoyed Southland.
"We love the place to bits. It is a fantastic place. It is first-world. And everything is clean," Mr Korkie said.
"Friendly people, beautiful countryside. Everything works, and if we have a problem with anything someone can fix it up for us like that," Mr Steenkamp said, snapping his fingers.
"We are always telling Southlanders they should appreciate what they've got."
