Inflation Test under Simulated Space Conditions of the 4 M Diameter Miriam Balloon
Bayler, K.1; Griebel, H.2
1IABG mbH; 2Institute of Space Technology
In 2001 the "Mars Society Deutschland e.V." a privately funded non-profit society, started an extremely ambitious, some say an impossible undertaking, the project "Archimedes" (Arial Robot Carrying High Resolution Imaging Magnetometer Experiment and Direct Environmental Sensors).
Archimedes is a superpressurized hypersonic drag balloon, that is going to be launched to planet Mars as a scientific payload on AMSAT's P5A Mars satellite.
After successful Mars orbit insertion, Archimedes is separated from the parent spacecraft P5-A and de-orbited. Subsequently a balloon package is ejected, which is inflated to a spherical balloon of ten meters diameter. The de-orbit and inflation system is then pulled away from the fully inflated ARCHIMEDES flight system, which then is left to coast towards the planet. This trajectory is designed to let ARCHIMEDES pass through the atmosphere between two and nine times (aerobreaking) before the balloon finally enters the atmosphere for good and descends all the way to the ground. ARCHIMEDES starts to collect data about Mars with its scientific instruments, mounted inside a pod on the balloon's south pole from the moment the inflation system is jettisoned. The actual number of high altitude hypersonic passes through the atmosphere depends on local atmospheric conditions, but also on available navigational precision.
Archimedes is a demonstrator of a new atmospheric entry technique and explores Mars' atmosphere and surface. But its goal is also to arouse public interest in science and technology, especially with young people.
After seven years development and many different ground and flight tests, the next step in the development program is the second space flight test. The mission is named MIRIAM (Main Inflated Reentry Into the Atmosphere Mission test). It is primarily targeted at testing the whole process of ejection, deployment, inflation, and separation from the inflation mechanism. If these primary tests complete successfully, a high speed atmospheric entry flight test immediately follows. For this test, the MIRIAM balloon is geared up with a fully instrumented pod and balloon.
The launch of MIRIAM is slated for April 2008 on top of a two-stage ballistic rocket, REXUS-4, once again from ESRANGE, and it is expected to reach an apogee of around 200 km. MIRIAM will be packed inside a service module equipped with the deployment mechanism, an inflation system and a television subsystem for the observation of the deployment and inflation process. Miriam's instrument pod will carry a small commercial camera, a magnetometer jointly supplied by the Technical University of Braunschweig and Magson GmbH of Berlin, a pressure sensor provided by the Finnish Meteorological Institute as well as a suite of temperature sensors distributed around the balloon's hull. The flight will be recorded by a set of still image cameras, three television cameras (two on the service module and one which stays on the rocket), and live telemetry.
Miriam's balloon has a diameter of 4 meters and is made of UPILEX-25RN. It is a sealed, spherical overpressure type balloon formed by 32 meridian seams and one equator seam, yielding 64 segments plus pole reinforcements and fittings. Built into the balloon hull are an inflation hose with windsock, a UHF dipole antenna for the instrument pod's telemetry transmitter, and six thermistor elements to record hull temperature distribution during atmospheric entry and deceleration.
After the completion of the balloon, its inflation windsock, overall shape and air-tightness was tested successfully under ambient atmospheric conditions.
Miriam was then fully integrated, folded according to the geometry of the service module's balloon container, packed and inflated with Helium under simulated space conditions inside IABG’s 6-m thermal vacuum test facility. The presentation will show images and video footage of the various manufacturing, packaging and testing procedures of the Miriam balloon system.