MAPHEUS 12 sounding rocket – much to do before the countdown in northern Sweden
We're currently preparing the MAPHEUS 12 sounding rocket for its flight into microgravity. We have been at Esrange, a sounding rocket range operated by the Swedish Space Corporation (SSC) – approximately 45 minutes from Kiruna in northern Sweden – since last week. We are a team of 30 from the DLR Institute of Materials Physics in Space, together with the DLR Institute of Aerospace Medicine and DLR’s Mobile Rocket Base (MORABA) and we’re working around the clock, eagerly awaiting the launch.
++++ Update from Thursday, 20 October: Rocket ready for launch, now the weather must cooperate
Yesterday we had a successful test countdown for our sounding rocket MAPHEUS-12, so from a science and rocketry perspective we are now ready to launch. So now we are talking ... the weather. There will be no launch today, Thursday. High altitude winds too strong. The flight must be planned so that the rocket lands as close as possible to a specific point, with a predicted sway This must be small enough that the actual landing point is within the allowable zone.
The launch pad can be altered in orientation and inclination, for example, to allow for winds that affect the part of the trajectory that passes within the atmosphere to affect the flight. However, such an adjustment of the so-called launcher settings is only possible within certain limits. Before each planned launch, we therefore discuss the weather forecast to find the best possible time window for the launch. During the five-hour countdown, the weather forecast is then supplemented by accurate live data from local weather balloons. If - as was the case for today - all weather models lead to unachievable launcher settings already in the forecast, it makes sense to wait and see. The forecasts for Friday morning look much better! By the way: The Swedish Space Corporation (SSC) will stream the launch live on their Youtube channel. ++++
Sunrise at Esrange
MAPHEUS stands for ‘Materialphysikalische Experimente unter Schwerelosigkeit’ (material physics experiments under microgravity) and is a research and development programme thay has been carried out by the DLR Institutes of Materials Physics and Aerospace Medicine in collaboration with MORABA since 2009. MAPHEUS 12 will allow seven different experiments to spend around six minutes in microgravity. The experiments were developed and set up by our institutes together with several partners. This includes researchers from the Technical University of Munich, the University of Veterinary Medicine Hanover, the Leibniz Institute for New Materials in Saarbrücken, La Trobe University in Melbourne, Australia, and the company adesso SE.
The first week featured all kinds of preparations: after unpacking dozens of boxes and setting up the individual stations, the rocket systems and experiments had to be tested while the researchers hurriedly prepared their samples. A first important step is the 'bench test', in which all the experiment modules are laid out in a row together with the service units and electrically connected. Next, the payload can be integrated and brought into an upright position. This is followed by the first simulation of the flight process.
The preparation takes place in a separate hall in the launch area at Esrange. After about a week of preparation, we should be ready to bring the payload to the launch site and load it onto the engines of the sounding rocket.
SOMEX is one of the experiments on board MAPHEUS 12. It is a versatile experimental platform for 'soft matter' that offers many kinds of optical analysis techniques and can be used with a wide range of materials, such as colloidal suspensions, emulsions – materials commonly found in numerous everyday products such as milk or cosmetics – or biological fluids. SOMEX is designed to be a 'frequent flyer'. The most important hardware components remain, and only the sample holder is adapted for new experiments.
The current MAPHEUS flight is the first to carry an experiment designed by, the Leibniz Institute for New Materials in Saarbrücken. In cooperation with this partner, colleagues from the DLR Institute of Materials Physics are investigating the agglomeration of gold nanoparticles in space using laser light scattering and high-speed imaging. We want to learn how the process takes place over time. This requires making measurements during which the particles are suspended throughout the process. That is why the experiment will be conducted in microgravity during a high-altitude flight.
Testing new materials for lightweight, flexible and powerful solar cells under space conditions is the goal of the SVALIN experiment, conducted by Müller-Buschbaum's group at the Technical University of Munich. Together with the DLR Institute of Materials Physics in Space, they have built a high-altitude research module that has eight windows into which solar cell samples are inserted. This must be done during the countdown. The scientists want to understand how the newly developed materials degrade under harsh environmental conditions, and to do this, the cells should be placed on the rocket as late as possible.
To ensure that this will run smoothly, the procedure is practised during the preparations. During the countdown, the eight sample holders must be screwed on under difficult circumstances. Because the rocket is on a guide rail for the launch, some of the sample holders are difficult to reach and require a special tool. This is also something that needs to be thoroughly tested, especially during the test countdown.
Antiquated on the outside, but entirely new on the inside – the MAPHEUS service module
MORABA designs and builds the service module – the rocket's on-board computer, so to speak. The module takes care of transmitting the relevant signals to the individual experiments, such as those to indicate lift-off or the onset of microgravity. It also supplies them with power if they do not have their own battery pack. The service module also provides in-flight data, video communication and altitude and position information, and controls a cold gas system that allows the flight path to be adjusted if necessary. In this campaign, we are using a newly developed service module for the first time. Thanks to new hardware, it offers communication that is ten times faster, more precise position control and much more. It is also designed to be reusable, which means, following an overhaul, it can be deployed again in the next campaign.
Another important module of MORABA is the rocket engine ignition unit. It is responsible for igniting the rocket's second stage at an altitude of approximately 6.6 kilometres, shortly after the first stage has burned out. It is built by MORABA and must be extremely robust and reliable, as it is critical in terms of safety. MAPHEUS 12 will carry the refurbished ignition unit that was already used during the MAPHEUS 9 flight this year.
'Late check-ins' during the five-hour countdown
Once the payload is installed aboard the launch vehicle, the experiments can only be controlled remotely. All experiments with samples that cannot be kept outside for days – i.e., outside the warm laboratory environment – must be equipped with early or late access hatches. These are openings in the payload through which the samples can still be installed during the five-hour countdown. On board MAPHEUS 12, we have five experiments that require such a 'late check-in'. They are equipped with samples up to one hour before the scheduled launch.
As a rule, late check-in applies to all biology experiments. This time, DLR's Institute of Aerospace Medicine is participating with two experiments, MEA and GraviPlax. MEA is a multi-electrode array chip on which brain cells from mice, known as primary neurons, are grown. The experiment will study the changes in the firing behaviour of the neurons under hyper- and microgravity conditions. For these brain cells to survive, a sample temperature of 37 degrees Celsius must be maintained. Depending on the weather conditions in northern Sweden, this can be quite a challenge. The team has developed an analogue heater that has been carefully checked to ensure that it does not emit high-frequency electromagnetic signals while keeping the sample at the right temperature. Such radiation is prohibited when people have to work in the launch vehicle.
The second DLR Aerospace Medicine experiment, GraviPlax, is flying for the second time and will offer insights into the gravitational sensing of cells. It flies with simple organisms (Trichoplax adhaerens), which are studied in hyper- and microgravity. The University of Veterinary Medicine Hanover and La Trobe University in Melbourne, Australia, are joining us for the campaign. The experiment is controlled by a small electronic board with enough space for another microcontroller, on which the researchers are testing the cryptographically secure recording of sensor data together with the company adesso SE.
Last Monday, we were able to install the engines and payload into the launcher. After that, it took another full day to install the ground-based equipment. The individual modules are typically connected with various supply cables to provide them with power and data links to the computers on the ground. In this way, the experiments can be controlled and prepared for launch during the countdown.
All steps are subjected to intensive testing: numerous communication checks and test runs are carried out during every major operation. As a lot of equipment from different parties is involved, it remains almost inevitable that a problem will occur at some point. Fortunately, we have only had to fix minor ones during the campaign so far. Now it's time to cross our fingers for the launch!
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