Researchers simulate Mars atmosphere

Project investigates entry of spacecraft into the Martian atmosphere

Glowing particles in the arc-heated wind tunnel: The data for the numerical computer models come from wind tunnel experiments, which simulate the physical properties of Mars. In the Martian atmosphere, for example, there are more particles than in the Earth's atmosphere, which means a higher frictional resistance. © DLR
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Yesterday, an international project to simulate the entry of spacecraft into the Martian atmosphere has begun. Among other things, a team of German, Russian and Italian scientists in the Cologne wind tunnel investigates the Martian atmosphere - another important step on the way to future manned or unmanned naval expeditions.

The data collected in the context of the SACOMAR project - Safe and Controlled Martian Entry - are intended to help, among other things, the development of novel heat protection concepts and materials. But they could also have an influence on the aerodynamic design of spacecraft.

Mars reveals secrets

The exploration of Mars has made great progress in recent years. Space missions such as "Mars Express" have significantly improved knowledge about the "Red Planet". Nevertheless, many questions about the nature, development and development of our neighbor planet are still open. Answers to these questions can only be found on the surface of Mars.

In order to land safely there, the hurdle of the Martian atmosphere must first be taken. Here begins the work of the research group led by Ali Gülhan of the German Aerospace Center (DLR).

Hot entrance

Similar to the reentry of spacecraft into the Earth's atmosphere, a spacecraft has to withstand tremendous temperature loads when entering the Martian atmosphere. For this reason, both landing capsules and space shuttles are protected by a heat-absorbing layer. Among other things, this can consist of organic material - which burns on entry - or ceramic structures. display

Past Mars missions had limited information about the composition of the planet's atmosphere. Precise predictions of the expected temperatures when entering the Martian atmosphere were only partially possible. Therefore, for safety reasons, the heat protection was designed with large tolerances. However, this oversized heat protection had a negative impact on the scientific payload of the spacecraft. The current research should improve this.

Computer simulation of the flow behavior of the hot gases entering the atmosphere: An accurate prediction of the distribution of the heat flux on the surface of the space capsule, which enters the atmosphere with hypersonic sound, is f Einer a fundamental improvement in the entry technology indispensable. To simulate the flow distribution, computer simulations are often used. The data for these computer models comes from wind tunnel experiments, which simulate the physical properties of Mars. DLR

Reconstructed Martian atmosphere

An accurate prediction of the distribution of heat flux on the surface of the space capsule, which enters the atmosphere with hypersonic noise, is indispensable for a fundamental improvement in the entry technology. Computer modeling is often used to model high-temperature flow. For this purpose, the TAU calculation method developed by DLR is used.

The data for these computer models comes from wind tunnel experiments, which simulate the essential physical properties of Mars. In the Martian atmosphere, for example, there are more particles compared to the Earth's atmosphere, which significantly increase the erosion of the heat protection.

Model in a simulated Martian atmosphere: In K ln, researchers have access to an arc-heated wind tunnel, where models can be exposed to real heat loads. Optical and electronic measuring technology can be used to investigate the flow behavior of the hot gases and the selective heat load of individual parts of the model. The space capsules penetrate into the atmosphere with their blunt underside leading to a kind of shock wave at high temperatures, while the gases flowing past at the rear clearly show are there. DLR

Wind tunnel with arc heating

In K ln, researchers have access to an arc-heated wind tunnel, where models can be exposed to real heat loads. This plant allows the flow field of the Marsein entrance with dust particles to replicate and to investigate the behavior of the heat protection material with the help of optical and conventional measuring techniques.

While the front side of the space capsule is exposed to higher thermal loads, the relatively cool and thin flow on the rear side determines the vehicle's dynamic flight stability. In addition, experiments are carried out at DLR in G ttingen to determine the influence of the gas composition on the heat flow. The numerical simulation and wind tunnel data are used in the development of novel heat protection concepts and materials and have an influence on the aerodynamic design of spacecraft.

International and interdisciplinary

In addition to fluid and material research, the interdisciplinary research project SACOMAR also deals with the problem of the so-called blackout, the demolition of the radio link during the entry phase. Project Manager Gülhan on the potential of SACOMAR: "The project offers us the opportunity to study in detail the technological basics of maritime entry through the cooperation of scientists from different disciplines. The research results can contribute to ESA's ExoMars project. "

(German Aerospace Center (DLR), 21.01.2011 - DLO)