Weightless Plate Animals – How Gravity Affects Genetic Information

• On January 29, 2022, the DLR sounding rocket MAPHEUS-9 brought four experiments into weightlessness for around six minutes.
• The rocket, weighing 1.7 tons, took off from the ESRANGE launch site in northern Sweden and reached an altitude of 254 kilometers.
• Experiments from the fields of materials research and manufacturing technology, granulate physics and gravitational biology were also on board.

KIRUNA, Sweden (DLR PR) — Plate animals usually like it a little warmer. For science, the simplest multicellular animal in the world ended up in northern Sweden – and from there into weightlessness for a short time. On January 29, 2022, the marine organisms were successfully lifted off the rocket launch site on board the MAPHEUS-9 sounding rocket operated by the German Aerospace Center (DLR) at ESRANGE (European Space and Sounding Rocket Range). Three other experiments from the fields of physics, materials research and manufacturing technology also enjoyed six minutes and ten seconds in zero gravity.

The 11.7 meter long rocket with a launch weight of 1.7 tons reached a maximum altitude of 254 kilometers in just under 15 minutes between takeoff and landing. The payload carrying the science experiments flew an altitude parabola after the boosters were separated. It landed slowed down by a parachute and was rescued by helicopter. the Mobile Missile Base Division (MORABA) of DLR prepared and carried out the flight campaign. It also provides the recovery system, service module, cold gas control system, separation and ignition systems, telemetry station, launch pad and the rocket hardware.

GraviPlax: How did gravity shape the appearance of cells and organisms?

Despite their simple structure, plate animals – Trichoplax adherens – can distinguish between above and below, i.e. they can perceive gravity. Around 450 specimens of these marine organisms, which are only 0.5 millimeters in size, were on board the MAPHEUS-9 mission. The scientists were particularly interested in how weightlessness affects the plate animals. 

“We look at the genetic responses of organisms in weightlessness. We pay particular attention to the gene groups that are responsible for the polarity, i.e. the structure of our cells in the body. The polarity is lost when cancer develops,” summarizes gravitational biologist Dr. Jens Hauslage from the DLR Institute of Aerospace Medicine. 

In the GraviPlax (Gravitation/Trichoplax) project, DLR is working with teams from the University of Veterinary Medicine Hanover (TiHo) and the Australian La Trobe University in Melbourne. They carry out the molecular-biological analyzes in order to precisely understand the effects on the cells. The tiny organisms have all the important sets of genes needed to study and better understand these fundamental mechanisms.

GRASCHA: How do granules get their properties?

Granules are granular solids such as powder, soil, or gravel. Their physical properties are not so easy to understand. Because they depend crucially on how tightly a granulate is heaped up or “packed” in technical jargon and how compacted or compressed it is. In the experiment GRASCHA ( GRA nular S ound CHA racterization or GRA nulat SCHAll) spherical particles of glass with diameters of three to four millimeters are used as granules. With their help, the scientific team wants to test existing and new theories that explain the loss of mechanical stability in granulate packs. 

“We have the chance to gain a fundamental understanding of how granules get their properties,” explains DLR researcher Dr. Karsten Tell from the Institute for Material Physics in Space. “This is important in the field of geophysics, among other things. For example, if you want to understand why the ground sometimes suddenly starts to slip. It consists of nothing but solid particles. Small changes in their arrangement can lead to the ground no longer behaving as a solid, but more like a liquid.”

In addition to landslides, avalanches can also be better explained with this knowledge. The findings can also be of interest to the chemical and pharmaceutical industry. This is because powdery substances are often used there, which you want to process, convey and mix as well as possible. The same applies to sand and cement in the construction industry. 

The phase of weightlessness during the MAPHEUS-9 flight made it possible to arrange the particles of the granulate so loosely that that they were still in contact with each other. This state cannot be created on earth due to gravity and hydrostatic pressure. With the slightest vibration, the granulate pack loses its stability in weightlessness – referred to in technical jargon as the shear modulus. It is precisely this process that interests the researchers the most. 

To study it, they measure the speed of sound and shear waves. This shows how quickly the shear modulus decreases when the packing pressure is reduced. It is precisely this process that interests the researchers the most. To study it, they measure the speed of sound and shear waves. This shows how quickly the shear modulus decreases when the packing pressure is reduced. It is precisely this process that interests the researchers the most. To study it, they measure the speed of sound and shear waves. This shows how quickly the shear modulus decreases when the packing pressure is reduced.

MARS: 3D printing with powders in zero gravity

For the third time, the MARS experiment (metal- based additive manufacturing for aerospace and S weightlessness applications) on the short journey into space. The focus was on further work to research 3D printing, especially with powdered substances, under weightlessness. The DLR team from the Institute of Materials Physics in Space had already produced a first workpiece made of metallic solid glass on previous flights. The task now was to further optimize the process.

“The main challenge is to apply the powder evenly to the surface in a short time under zero gravity or with little gravitation,” describes DLR researcher Mélanie Clozel. “With every flight of our experiment into weightlessness, we have the opportunity to further develop and test our approaches and thus increase our know-how. Metallic solid glass is characterized by its high strength and corrosion resistance. Both are important properties for use in space. In the future, components could also be manufactured directly in space using 3D printing, for example on space stations. Regolith – powdered rock dust – could also be used on the surface of the Moon or Mars to make components, for example.”

SOMEX: Soft matter under the laser magnifying glass

The experiment platform SOMEX ( SO ft M atter EXperiments) enables various experiments with soft matter in weightlessness. She was also part of the MAPHEUS-9 flight campaign. Soft matter is a variety of materials that consist of two phases. They are between the solid and liquid states of aggregation. These include, for example, gels and viscous liquids such as soap or paint, granules, foams and also biological cells. 

With the help of laser measurement methods, the scientists have tracked down two physical phenomena this time: With the help of artificial microswimmers, the researchers want to better understand the effects of movement, as we know them from living organisms. This includes, for example, the swarming of bacteria. They used tiny little glass balls, floating in a solvent. These were provided with a coating that absorbs light very strongly. If the glass beads are irradiated with a laser, they absorb the light or heat energy and move. 

In addition to the GRASCHA experiment, they also investigated granules: Here, too, the focus was on how the individual particles of the granulate move. In this way, new insights into the structure and dynamics of such systems can be gained experimentally and compared with theoretical models. In addition to the GRASCHA experiment, they also investigated granules: Here, too, the focus was on how the individual particles of the granulate move. 

In this way, new insights into the structure and dynamics of such systems can be gained experimentally and compared with theoretical models. In addition to the GRASCHA experiment, they also investigated granules: Here, too, the focus was on how the individual particles of the granulate move. In this way, new insights into the structure and dynamics of such systems can be gained experimentally and compared with theoretical models.

About MAPHEUS:

The MAPHEUS high-altitude research program ( Ma terial PH ysical experiments under p _ _weightlessness) of the DLR Institute of Materials Physics in Space has been carried out for 13 years. It enables scientists inside and outside DLR independent and regular access to experiments in microgravity. Progress in the field of measurement technology and the realization of highly developed flight hardware go hand in hand with trend-setting experiments in the field of materials and life sciences. Due to the corona pandemic, the planned flights had to be changed: campaign 11 took place in May 2021, followed by campaign 10 in December 2021. For the third time, the sounding rocket was powered by an IM-IM configuration.