MAPHEUS - The Maiden Flight of a New Vehicle for Microgravity Experiments

Abstract

There are numerous materials science experiments in microgravity, which can be realized on sounding rockets, e.g. the gelation of aerogels, directional solidification of alloys and diffusion measurements in metallic melts. Such a rocket must offer a period of good microgravity-conditions for more than 120 s. The MAPHEUS (Materialphysikalische Experimente unter Schwerelosigkeit) rocket of the German Aerospace Center DLR meets these requirements. The payload is based on modules with 356 mm diameter, which are also used in the REXUS project. MAPHEUS implements the newly developed REXUS service-system. This service-system can control the power supply and handles data communication and time event management of the scientific experiments. An RCS-Module (Rate-Control- System) has been designed and built. This module contains a tank filled with pressurized gas (nitrogen), solenoid valves and nozzles, which are used to reduce the spin during the ballistic flight phase to less than 30°/min providing excellent microgravity conditions. During the maiden flight, in May 2009 at Esrange, Sweden, the payload was transported with a double stage solid propellant rocket up to an apogee of about 140 km. The first stage, a Nike motor, burned for 3.5 s and then, 9 s after lift-off, the second stage, an Improved Orion motor, ignited. At an altitude of about 70 km a yo-yo system decreased the rotation of the vehicle about its’ longitudinal axis, which was spin-stabilized during the ascent. After the second stage was separated and the rotation rates were reduced by the RCS, the experiment phase began at an altitude above 100 km. The scientific payload of MAPHEUS-1 consisted of three DLR internal experiment modules and a battery module from the DLR Institute of Materials Physics in Space, a measurement platform from the University of Applied Science Aachen, and the RB-MUSC from DLR Köln. The three material science experiments launched were AEROGET, an experiment to create frequency doubling aerogels, ATLAS-M, an experiment for diffusion measurements in molten metals and ARTEX-M, an experiment for directional solidification of AlSi-alloys. After the experiment phase, the payload re-enters the atmosphere and was decelerated by the aerodynamic drag. At an altitude of about 4.6 km the parachute system was released and the payload thus decelerated to a terminal velocity of 8 m/s. The DLR Institute of Space System was responsible for the project management and the DLR Mobile Rocket Base provided the rocket hardware and conducted the operations during campaign. This paper gives an overview of the MAPHEUS-1 vehicle, the experiments, the successful maiden flight of the rate-control-system and the campaign. It also includes flight results and gives an outlook on the MAPHEUS programme.