资源环境科技发展态势分析平台

It is a small piece of cargo – not even half the size of a shoebox – but a group of students from Frankfurt are still tracking its progress with breathless anticipation. After all, the delivery address is none other than the International Space Station (ISS). The contents of the 10 x 10 x 15 centimetre container? An experiment that is set to be performed on the ISS. It is housed in a Cygnus Transporter on board the Antares rocket that set off for the ISS from Wallops Island, Virginia (USA) on 15 November 2018 at 10:01 CET. If all goes according to plan, the freighter will dock to the ISS on 20 November. The student team from the University of Frankfurt is among the winners of the High Flyers competition organised by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) Space Administration.

The prize awarded to the young scientists provided them with the opportunity to send their own experiment to the ISS and conduct research under space conditions. "We watched the launch with plenty of anticipation and a little nervousness. Of course, now we are delighted that everything went so smoothly and our experiment will soon arrive at the ISS," reports Tamara Koch, EXCISS team leader.

The students from the University of Frankfurt will use EXCISS (Experimental Chondrule Formation at the ISS) to investigate the formation of chondrules. These play a role in the formation of planets. The experiment involves exposing a small quantity of sand dust particles located in a glass chamber to high-voltage lightning flashes. A microscope is used to observe how the particles melt and agglomerate to form clumps. Two additional experiments from the current High Flyer competition are already on the ISS.

"The idea behind the project is simple", explains EXCISS team leader Tamara Koch. "We want to induce collisions between dust particles in a microgravity environment, under the same conditions as those that prevailed in the solar nebula. They form clumps of dust, which we then bombard repeatedly with lightning. What makes the idea new is performing it under realistic, microgravity conditions with low gas pressure. On Earth, experiments like this are not even possible in a drop tower. The ISS therefore provides a unique setting to test the nebular hypothesis."

Students from all the universities in Germany were invited to submit experiment proposals to the High Flyers competition from 14 December 2016 to 28 February 2017. In particular, the criteria for examining the proposed experiments included their scientific merit, technical maturity and practical feasibility. The astronaut Gerhard Thiele sat on the selection committee alongside experts from DLR and the Deutsche Physikalische Gesellschaft (DPG). In May 2017, the committee finally selected three proposed experiments to travel to the International Space Station.

In addition to the EXCISS experiment by the Frankfurt students, the selected proposals were developed at the universities of Stuttgart (PAPELL) and Duisburg-Essen (ARISE). The latter two have already been put to the test of space compatibility, after departing Cape Canaveral on a Falcon 9 rocket on 29 June 2018. For the PAPELL (Pump Application using Pulsed Electromagnets for Liquid relocation) experiment, the young scientists from the University of Stuttgart designed an innovative pump technology that does not include any mechanical components and that might be suitable for supplying fuel on space missions. The ARISE (Planet formation due to charge induced clustering on ISS) experiment explores the role of electric discharge in the formation of planets. "It is a pleasure to see that after around 18 months of hard work by the teams, all three experiments will be brought together on the ISS,” says Johannes Weppler, competition project manager at the DLR Space Administration. “It is really impressive to witness what the teams have accomplished in such a short time."

During their projects, the three student teams completed the entire process of a real space mission – from formulating the scientific objectives and preparing the technical design and necessary tests, through to operation of the experiment on the ISS. There are limits on the size of experiment assemblies: they need to fit into containers measuring just approximately 10 x 10 x 15 centimetres. All of the assemblies are scheduled to remain in operation on the space station for at least 30 days. In addition, DLR made it possible for the three winning teams to witness the rocket launch live from the control centre. The many different tasks could only be completed with multidisciplinary teams that were willing to be committed and work as a team for a period of around 18 months.

The three experiments are scheduled to return to Earth on board a Dragon capsule in mid-January 2019, after which the students will be able to perform additional analyses. The High Flyers student competition is organised by the DLR Space Administration and supported by funds provided by the German Federal Ministry for Economic Affairs and Energy (BMWi). The US company DreamUp provides technical expertise, supports the students in designing the experiments and handles transport of the experiments to the ISS. Experts from the DPG assisted DLR in selecting the experiments and contribute their know-how in many disciplines of physics research, also in later phases of the competition.