Expert

Expert [ESA]

The Expert (European eXPErimental Reentry Testbed) reentry vehicle is a flight testbed aiming to obtain aerothermodynamic (ATD) flight data to validate design tools, ground test facilities and verification techniques. The design and verification of future atmospheric missions will benefit significantly from flight validation of ATD methods, reducing uncertainties and improving reliability.

The entry parameters have been chosen in order to correlate the flight measurements with the conditions simulated by ground facilities available in Europe, including plasma wind tunnels such as the Scirocco in Italy and Plasmatron in Belgium. This will allow validation of the ATD physical models with real flight conditions and correlation of ground testing facilities.

The top level mission objectives are:

• To obtain flight data associated with critical ATD phenomena, such as boundary layer transition, gas surface and shock layer interactions, real-gas effects and plasma chemical composition
• To reduce design margin and uncertainties using in-flight measured data to validate numerical database, computer fluid dynamic tools and to correlate ground test results
• To develop engineering technologies and advanced materials for thermal protection system, and experiment with new instruments and advance sensors for ATD measurements techniques
• To gain engineering knowhow within European industry on the development of reentry and transportation systems, increasing the Technological Readiness Level of these technologies.

The rocket will be launched from a Russian submarine in the Pacific Ocean and Expert will land on the Kura test range on the Kamchatka Peninsula in the Russian Far East.

The Volna launch vehicle plays a crucial role in the overall mission and scientific objectives. Expert is a ballistic reentry capsule and therefore relies solely on the Volna to propel it on a suborbital trajectory up to 120 km altitude and a speed of 5 km/s (18000 km/h).

Volna then points the uncontrolled capsule in the correct orientation and releases it to enter Earth’s atmosphere and perform the scientific parts of the mission. The capsule’s shape, weight distribution and parachute are all designed to ensure that Expert follows a stable path back through the atmosphere to its landing site.

Makeyev will also coordinate the capsule search and recovery operations at the Kura military test range. The search and recovery is performed by helicopter and uses beacon signals from the capsule to pinpoint the location.

The recovery team will wait at the edge of the landing zone and then track the beacon signal directly to the touchdown point. Two beacons are used for redundancy. After finding the capsule, safety and inspection operations will be performed. The scientific and housekeeping data are then retrieved from the redundant and crash-resistant memory units.

Expert's mission is a suborbital ballistic reentry flight. The initial reentry velocity is 5 km/s, with a flight path angle of -5.5 at an altitude of 100 km. Originally ESA contracted with Makeyev for the launch from a Russian submarine on a Volna rocket, but the Russian Ministry of Defence did not agree to provide the rocket.

Currently ESA is evaluating alternative launchers: the US Pegasus-Lite, Minotaur, Athena-1c, a Lockheed solid two-stage launch system with hydrazine upper stage being dropped from a C-17A or a sounding rocket. A launch on the now cancelled SWORDS launch vehicle then under development was also considered.