During the period from 2001 to 2003 the MSD was actively involved in the missions with MDRS and the preparation of the EuroMars project. In 2003 the EuroMars project came to a halt and the MSD concentrated its resources on the ARCHIMEDES project, studied since 2001.

In 2003 the MSD organized the 3rd European Mars Society Conference (EMC3) in Bremen. The MSD participated also regularly with presentation papers on Archimedes and other subjects in the Mars Society Conferences in Europe and the US and in other scientific and public events.

The exploration of the Mars atmosphere constitutes an important area of research also in preparation of manned Mars missions where large vehicles descend through the Mars atmosphere down to the Mars surface. Up to now a measurement of the Mars atmosphere was only possible from the orbit by remote measurement or on the ground by Mars explorers landed on Mars. With the Mars Balloon probe ARCHIMEDES it will be possible for the first time to perform measurements of the Mars atmosphere “in situ” while descending with a 10-m balloon with an attached scientific measurement package slowly through the Mars atmosphere by means of a balloon inflated in space, carrying a scientific payload. This is the principle of the Mars Balloon probe ARCHIMEDES.
ARCHIMEDES would be carried as passenger on a Mars probe. It was foreseen so far to use a satellite of the radio amateur organization AMSAT, which would be well suited due to its configuration. This satellite, called P5-A, would release the entry vehicle carrying the ARCHIMEDES balloon in a Mars orbit together with its propulsion module. The balloon would then be deployed and inflated in space, be brought on an entry trajectory, be released and then enter the Mars atmosphere for descent to the Mars surface.

The satellite would remain in Mars orbit and transmit the data from ARCHIMEDES down to earth.

The P5-A satellite has the advantage to provide ARCHIMEDES the additional propulsion needed to descend down to Mars from an ellipitcal Mars orbit of the P5-A. ARCHIMEDES will be integrated into the propulsion module of the P5-A, which will separate from the P5-A orbiter and then descend to a Mars entry trajectory before setting the inflated ARCHIMEDES balloon free for his final entry and descend mission phase.

Besides the atmospheric measurement package ARCHIMEDES would carry additional scientific instruments measuring the aero-thermodynamic behavior of the balloon, the residual magnetic field of Mars, the deceleration and the balloon position. Cameras would take pictures of Mars from the orbit and during the descent.

The ARCHIMEDES project introduces several innovations:

•    inflation of a balloon in free space
•    deceleration of the balloon by the Mars atmosphere
•    entry in the Mars atmosphere
•    development of balloon technologies for
o    Material
o    Manufacturing
o    Testing
o    Long-term storage
o    Deployment, inflation and release
Extensive ground testing is required to verify these technologies. So far several flight simulation tests have been performed
•    successful balloon deployment tests under low-g conditions in parabolic flights 2006
•    a first sounding rocket test in 2006 testing the balloon deployment storage and release system, proving the validity of the design
•    the full flight test MIRIAM with all balloon related equipment operational in a downscaled model with a 2.5 m balloon instead the 10 m planned for Mars on another sounding rocket in 2008. This test was only partially successful and is planned to be repeated with an enhanced test system MIRIAM-2 in 2014. The Marsflight could take place in  2021.

The MIRIAM-2 Flight Test Program

So far extended flight testing under low gravity conditions was performed with the objective of verifying the scientific hypotheses and conclusions and the resulting design of ARCHIMEDES. In 2005 the critical balloon deployment system was successfully tested during short parabolic flights and later in 2006 during a sounding rocket campaign.


MIRIAM-B -the scientific entry vehicle- during entry in the Earth atmosphere

MIRIAM-1 mission scenario

In October 2008 a full system test has been performed with the flight test vehicle MIRIAM, a 1:2.5 downscaled flight test model of ARCHIMEDES with a 4m balloon. MIRIAM has been launched on a REXUS 4 sounding rocket of DLR-Moraba into 170 km altitude in Kiruna in Northern Sweden. The MIRIAM mission should simulate the ARCHIMEDES mission in the higher earth atmosphere at conditions similar to the Mars mission.

MIRIAM has been developed by the MSD in cooperation with the University of the German Armed Forces in Neubiberg and IABG in Ottobrunn, both near Munich.

The development of the balloon is a hight-tech undertaking. The balloon must have a near perfect spheric shape. Therefore he has to be composed of as many single sections as possible, which must be seamed together in an extremely accurate manner. Specific tooloing had to be developed for this purpose. The balloon material must be lightweight, rigid, withstand high temperatures up to 300 degrees C, and be flexible enough to be folded and stowed in a small container.

The selection of the balloon material was subject to a long analysis, selection and testing process.

MIRIAM-1 in flight configuration (still without its thermal isolation)

Unfortunately the MIRIAM flight test was only a partial success due to late separation of the MIRIAM flight vehicle from the REXUS 4 carrier. This led to the disturbance of the subsequent mission sequence, resulting in an only partial inflation of the balloon and its off-nominal release.

Although the MIRIAM mission did not produce the data expected on the balloon entry behaviour, the mission sequence and the very complex balloon storage, deployment, inflation and release system worked as planned. The MSD decided therefore in early 2009 to maintain the basic MIRIAM design and experience for another similar mission, called MIRIAM-2. The entry part, consisting of the balloon with the electronics unit, is now called MIRIAM-B. Its development has been taken up mid 2009 with the objective of a launch in 2013.

“Lessons-learned” changes, which will be introduced for MIRIAM-2 include the replacement of the separation system by a proven design, an update of the electronics systems, and the provision of an access capability to the instrument pod electronics and batteries without disassembly of the vehicle, allowing late access to the batteries and electronics in case of launch delays, or for test purposes. Mission objectives will be enhanced by adding additional sensors, a GPS and an internal camera monitoring the balloon behaviour during entry. Modifications of the balloon manufacturing techniques will be closer to the ones to be used for the Mars mission.

The configuration of MIRIAM-2 will be simplified, compared to MIRIAM, by avoiding one of the three separation events necessary to set the inflated ballon free in 150 km altitude. This becomes feasible, since the nose cone will remain connected to the Service Spacecraft portion of MIRIAM-2. This requires changes to the mechanical configuration od the Service Spacecraft.

In 2011 a so-called “Preliminary Requirements Rewiew” (PDR) has been performed fixing the requirements for MIRIAM-2.

MIRIAM-2 is planned to be launched in October 2014 onboard a sounding rocket MAPHEUS by the provider of the launcher and launch services, DLR-Moraba in Oberpfaffenhofen near Munich.

The MIRIAM-2 flight test constitutes an indispensable stepping stone to the ARCHIMEDES Mars mission, which may take place in 2018 at the earliest.  The results of the MIRIAM-2 mission will show, if additional tests are required