The KRACO re-entry capsule, developed at the Institute for Space Systems (IRS) at the University of Stuttgart, has successfully launched to the International Space Station (ISS) as part of the international KREPE-3 mission led by the University of Kentucky in Lexington. The capsule was developed by the High Enthalpy Flow Diagnostics Group (HEFDiG) at the IRS and is now aboard the Cygnus NG-24 supply transporter en route to the ISS. The spacecraft launched on April 11, 2026, from Cape Canaveral aboard a SpaceX Falcon 9 rocket—watched from afar by HEFDIG group leader Stefan Löhle and his team.
Innovative Materials for Re-entry
The KRACO capsule is part of a set of twelve experimental capsules that will investigate key questions regarding the atmospheric re-entry of spacecraft as part of the KREPE-3 mission. Prof. Alexandre Martin (University of Kentucky), project leader of KREPE 3, proposed to the HEFDIG group that they develop their own capsule and facilitated its integration into the KREPE mission. “With KRACO, we can investigate for the first time under real re-entry conditions how our heat shield material HARLEM performs and whether the violet marker actually works in a real-world environment,” explains Stefan Löhle. “The data obtained will certainly help improve the efficiency of future re-entry capsules.”
A key feature of the KRACO capsule is the heat-shielding material HARLEM (HEFDiG Ablation-Research Laboratory Experiment Material), developed by HEFDiG. This material is partially coated with a violet spectral marker, which enables the capsule to be visually identified during reentry and facilitates its remote observation. In addition, KRACO is equipped with sensors specially developed by the IRS and the University of Kentucky. During reentry, these sensors transmit measurement data via radio to Stefan Löhle’s team. The data provides valuable insights into thermal stresses and the behavior of heat shield materials under real reentry conditions.
Contribution to the Preparation of Future ESA Missions
The name KRACO is derived from the European re-entry capsule DRACO (ESA Re-entry Capsule), scheduled for 2027. Through its shape and special coating with the spectral marker, KRACO is designed to address key issues for this future mission. KRACO can thus be understood as a so-called de-risking mission: technologies and measurement methods are tested under real-world conditions to reduce risks for future European space projects.
Re-entry observation planned
After docking with the ISS, the Cygnus cargo spacecraft will initially resupply the space station for several months. The module is scheduled to undock in November. During the subsequent re-entry over the South Pacific, the twelve experiment capsules will be released—including KRACO.
While each capsule investigates different aspects of reentry, KRACO focuses specifically on the performance of the HARLEM heat shield material and its spectral marker. The HEFDiG team also plans to observe the reentry from a research aircraft. This will allow the capsule’s telemetry data to be combined with optical measurements afterward.
Contact:
Dr. Stefan Löhle
HEFDIG Group Leader
Phone: +49 711-685-62387
Email: loehle@irs.uni-stuttgart.de
Dr. Dörte Mehlert
IRS Public Relations
Phone: +49 711-685-69632
Email: doerte.mehlert@irs.uni-stuttgart.de
Further links related to this news:
- High Enthalpy Flow Diagnostics Group (HEFDiG)
- KREPE-3 Flight: Send Off, University of Kentucky News, February 20, 2026
- NG-24 mission page from SpaceX
- Video of the Falcon 9 launch
- Intro starts at 12:03
- Video begins at 12:28
- Final countdown and liftoff: 23:07
Video of the Falcon 9 launch with the KRACO capsule on board.
Aerospace research at the University of Stuttgart
Aerospace studies in Stuttgart form a unique interdisciplinary think tank for key technologies in space and on Earth. Researchers at the University of Stuttgart bring together expertise from the fields of climate and energy research, communications technology, propulsion technology, and AI-assisted flight. A central focus is the exploration of sustainable technological solutions aimed at minimizing the environmental impact of aerospace. Research is conducted in an interdisciplinary manner and in close collaboration with regional and international partners from academia and industry, for example within the framework of the Collaborative Research Centers ATLAS (SFB 1667) and SynTrac (SFB-TRR 364). As a partner of THE Aerospace LÄND, the University of Stuttgart contributes to the implementation of Baden-Württemberg’s state strategy to shape aerospace in a sustainable, digital, and collaborative manner by 2050. The University offers its students a solid engineering and application-oriented education. In promoting young talent, it cooperates with the “Future Initiative for Young Talent in Aerospace,” an initiative of the state of Baden-Württemberg dedicated to strengthening the promotion of young talent in STEM fields.
