From horizon to horizon - Alexander Gerst phones home

At about 16:30 on 26 July 2018, the main street of Künzelsau, Alexander Gerst's hometown, resembled a festival: around 5000 people were on their feet. The street was packed and everyone listened attentively to the stage announcements, waiting for the call from the ISS. The event had been underway since 11:00, starting with a press conference in the Town Hall. All that remained was to quickly integrate a few additional charts into the short presentation and then it would be underway. Following the official welcome and the opening address by the DLR press spokesperson, it was my turn, focusing on the experiments and benefits of research on the ISS. But just minutes earlier, I suddenly received an e-mail on my phone.

The MFX-2 planetary simulator of the DLR in Bonn and Berlin was up and running again. News that I had been waiting two weeks to hear. The problems had finally been resolved. Great news. With a little luck, the crew will still have time to measure the remaining material samples before we have to hand over the vacuum and cooling water connections to NASA. The press conference was followed by various press and radio interviews. Then it was time for the stage briefing, followed by a short break, before continuing with the live interview for a major TV channel. The stage show began shortly after, featuring a variety of music. The main street was closed to traffic and slowly filled up.

Live calls to the ISS are always very special

During live calls, the ISS must not fly over the location of the connection, because the United States TDRS satellites – three of which span our globe – facilitate the contact, thereby ensuring seamless transmission. At the start of the call, the International Space Station was flying over Mongolia. The signal came from a satellite via Houston by phone to Künzelsau, with an approximately five second time delay. At 17:15, an image appeared on the LED screen on the stage – we caught a glimpse of Mission Control in Houston. At that moment, Astronaut Reinhold Ewald called the ISS from the stage and cheers rang out along the street. Alexander Gerst smiled at the camera. He couldn't see us, but simply received an audio signal in his earphones.

On the street were coloured templates; the people gathered there held cardboard letters in the same colour, and on the presenter's command they formed ‘Hello Alex’ above their heads. The greeting was filmed from above using a drone. Alex later received the image via e-mail. He answered questions from Künzelsau residents and local government officials standing on the stage.

Such events are extremely important because they communicate space, science and research issues to Earth and to the taxpayers who fund it all. Many young people are therefore inspired to study MINT subjects. Then it was my turn. I didn't ask any questions, but thanked the crew who did a great job, and passed on the good wishes of the entire ground team and satisfied scientists. Alexander Gerst and the crew have resolved some problems in recent weeks. But the astronauts hardly every know if an experiment has produced successful data because the schedule is extremely tight and the evaluation is primarily undertaken on the ground.

Then the 20 minutes were up. The band played and the street slowly emptied. There were a few more interviews after the broadcast, before a long working day came to an end for us all. At around half past nine, we were sitting at a cafe on the main street. The bright light in the cloudless evening sky moved rapidly above our heads. We instinctively waved and again said 'Hello Alex', while the ISS continued to fly eastwards. We watched it fly past, until it finally disappeared over the Hohenlohe horizon.