When setting up a lunar station, technologies for the use of locally available materials are crucial. Such technologies drastically reduce the need for transportation from Earth. We aim to provide proof of a key technology, namely Mobile Selective Laser Melting (M-SLM) for terrain modelling i.e. for building large structures such as launch/landing pads, but also building infrastructures like shelters protecting astronauts or equipment against radiation and micrometeorites on the Moon. The M-SLM technology has the advantage that only electrical energy and a moving system are required. For M-SLM, a mobile high power laser beam is directed on lunar regolith leading to its melting. Subsequently, the melt cools down and solid structures are generated. The MOONRISE instrument should serve in a short-term mission as a proof-of-principle experiment for the M-SLM technology on the lunar surface. In a first step, an Engineering Model (EM) of our MOONRISE instrument with a volume of 10 cm x 10 cm x 15 cm and a mass of about 2.7 kg has been built and thoroughly tested on ground. It could be accommodated on a rover or a robotic arm to move the laser spot in order to create 1D, 2D and even 3D regolith structures on the Moon. Recently, three new projects have been initiated in order to (1) develop the MOONRISE payload towards a Flight Model (FM) with accommodation on a commercial lunar lander, in order to (2) apply 2D laser beam deflection techniques for process scaling on a potential follow-on payload and in order to (3) investigate the detailed process of regolith laser melting under lunar gravity conditions in the Einstein-Elevator.
A lot of investigations are ongoing for the development of laser systems with Alexandrite as active laser medium. These laser systems fulfill the general laser requirements for spaceborne Earth observation missions such as altimetry. However, to date, the laser systems and especially the coated Alexandrite crystals do not exceed Technology Readiness Level (TRL) 4. Therefore, the Horizon 2020 project GALACTIC was initiated to develop reproducible, fully European supplier-based functionally coated Alexandrite crystals, which show at least the same optical quality and laser performance in comparison to the components from the leading suppliers on the global market (mainly US and Chinese companies) and further fulfill the qualification to be generally used in space (i.e. verification of TRL 6). We present the high optical quality and good laser performance results of our developed Alexandrite crystals tested in a cavity-dumped Q-switched laser system. Furthermore, we show on the one hand the reproducibility and on the other hand the competitiveness of our crystals by a comparison study with our GALACTIC samples and crystals from two non-European suppliers. Additional presentation content can be accessed on the supplemental content page.
Despite the extensive studies of Alexandrite as a potential laser-active medium for future Earth observation space missions in the last years, the corresponding laser systems and especially coated Alexandrite crystals do not exceed Technology Readiness Level (TRL) 4. This means that although the developed Alexandrite-based laser systems have been validated in the laboratory, it has not been published up to now, whether they can withstand the harsh environmental conditions in space. In the course of the Horizon 2020 project GALACTIC, high-quality functionallycoated Alexandrite crystals developed and manufactured within the GALACTIC project will be qualified according to TRL 6 in an environmental test campaign comprising irradiation and thermal cycling tests together with optical performance tests before and afterwards (functional laser tests, LIDT, and transmission measurements). In this work, we present our strategy for testing functionally coated alexandrite crystals for space applications developed, fabricated and tested in a fully European supply chain within the GALACTIC project with the goal of increasing the TRL level to 6.
Modern laser systems have paved the way for spaceborne laser applications such as Earth's surface and atmosphere monitoring. Well known technologies like Nd:YAG lasers are often employed; however, they do not always comply with all the different requirements for space missions. High optical efficiencies and tunable wavelength, which are desirable for many applications, can be reconciled with a simple laser design employing Alexandrite crystals. Horizon 2020 project presented here discuss the results on the development of alexandrite laser crystal treatment prior to coating deposition, as well as future plans on crystal interference coating deposition for LIDT improvement.
Spaceborne Earth observation based on laser instruments provides new technologies to monitor the atmosphere or our planet’s surface. Space-qualified Alexandrite laser crystals show convincing properties as a laser-active medium in high power laser systems for space-based missions, e.g. the wavelength tunability and the excellent material properties, such as high thermal conductivity and a good breaking strength. Therefore, the Horizon 2020 project GALACTIC was initiated to realize space-qualified, high-quality coated Alexandrite crystals relying on a purely European-based supply chain. The project consortium will push the development of Alexandrite crystals and coatings within the EU from the current Technology Readiness Level (TRL) 4 up to TRL 6. The Horizon 2020 project GALACTIC, which will be presented, has been initiated to realize space qualified high quality, high performance coated Alexandrite crystals rest on a purely European-based supply chain. The project consortium, consisting of Optomaterials S.r.l., Altechna Coatings and the Laser Zentrum Hannover e.V., provides the necessary expertise in the fields of laser crystal growth, optical coatings and laser systems to push the development of high quality, high damage threshold Alexandrite coatings within the EU up to TRL 6. In order to reach the GALACTIC goals, different technology areas will be addressed. On the one hand, Optomaterials S.r.l. as an experienced optical crystal manufacturer will continuously refine the crystal growth process and improve the raw crystals as well as the cutting and polishing quality step-by-step. As an experienced company in optical coatings production for space applications, Altechna Coatings will secondly develop high quality, low loss, high damage threshold coatings specifically tailored for application onto Alexandrite laser crystals. The superior performance of the coated crystals will then be proven in demonstrator laser systems. The Laser Zentrum Hannover e.V. has the required knowledge to set up laser demonstrator prototypes, whose specifications mimic typical earth observation laser source requirements. Finally, the GALACTIC consortium will work closely together to characterize and qualify the developed coated laser crystals. By collaborating with the European space industry and deriving the detailed requirements from typical earth observation space missions, a detailed TRL 6 components test plan will prove the TRL 6 qualification of the developed coated laser crystals. This will conclude the development process and will enhance the European non-dependence status of the Alexandrite laser crystal market. At the conference, we will present the project and its consortium as well as detailed strategies to enable a non-dependence of Europe on coated Alexandrite laser crystal technology and enabling long term European availability of this technology. This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No 870427.
KEYWORDS: Crystals, Laser crystals, Alexandrite lasers, Alexandrite, Space operations, Laser systems engineering, Laser applications, New and emerging technologies, Manufacturing, Laser development
Alexandrite is a promising, highly efficient laser material enabling wavelength tunability for applications in the field of spaceborne Earth observation. The Horizon 2020 project GALACTIC has been initiated to establish a fully Europeanbased supply chain for high-quality functionally coated Alexandrite laser crystals. To reach this goal, the project consortium, consisting of Optomaterials S.r.l., Altechna Coatings and the Laser Zentrum Hannover e.V., works closely together to firstly develop and improve the crystal manufacturing and coating technologies and secondly to characterize the developed coated laser crystals. Finally, the Technology Readiness Level (TRL) of 6 will be achieved for typical Earth observation space missions. The necessary qualification test campaign will conclude the development process and will enable European non-dependence from the Alexandrite laser crystal market currently dominated by non-European suppliers.
A hermetically sealed laser head (LH) emitting laser pulses at a wavelength of 266 nm has been developed and tested for the Mars Organic Molecule Analyzer (MOMA) instrument of the ESA/Roscosmos ExoMars 2020 mission. MOMA comprises a gas chromatograph (GC) and a laser desorption mass spectrometer (LDMS). Its primary function is to search for traces of present or past signs of organic molecules in subsurface material probes. The LH is used as an excitation source for the LDMS part of MOMA. Its design fulfils stringent mass and volume requirements and is realized as a hermetically sealed system. It consists of a laser diode pumped Nd:YAG based laser oscillator, a frequency conversion stage for frequency quadrupling of the fundamental laser oscillator wavelength, a compact monitoring stage for internal laser pulse detection, a beam shaping telescope and an adjustable laser beam steering unit with the purpose of guiding the generated UV laser beam to its target position in front of the mass spectrometer (MS) ion inlet.
The system has undergone extensive functional and environmental testing including vibration, shock and thermal vacuum chamber tests. After completion of the functional and environmental test campaign, the LH has been integrated on the MOMA mass spectrometer. Here we report on the mechanical design of this LH and its environmental testing. Furthermore, the LH was successfully tested both functionally and environmentally on LDMS level.
A space-qualified flight model of a pulsed ultraviolet (UV) laser has been developed for the Mars Organic Molecule Analyzer (MOMA) instrument of the ExoMars 2020 mission. The design is based on a passively Q-switched Nd:Cr:YAG laser oscillator with subsequent two-stage frequency quadrupling. It emits nanosecond pulses with an energy tuneable between 13 μJ and 130 μJ at a wavelength of 266 nm.
Considering its small physical dimensions and weight, the interior of the laser head is rather complex. Besides the aforementioned infrared oscillator and frequency conversion stage it contains the pump optics, two wavelength division assemblies within main beam path, a complex monitoring stage including two photodiodes for pulse energy measurement, a beam shaping setup and a deflection unit for fine adjustment of the beam pointing towards the sample location within the instrument. Most of the laser head is enclosed in a hermetically sealed housing, while the deflection unit is sealed separately. Both volumes are filled with 1 bar of dry, filtered air.
The flight model of the laser system for the Mars Organic Molecule Analyzer (MOMA) instrument within the ExoMars 2020 mission for Martian planetary surface exploration has been developed, assembled, tested, and finally integrated to the NASA Goddard Space Flight Center (GSFC) mass spectrometer. The nanosecond laser system consists of a longitudinally pumped, passively Q-switched Nd:YAG based laser oscillator with a two-stage frequency doubling to 266 nm. The laser design was implemented in robust and lightweight models of the laser head (LH) with the pump unit in a separate electronics box.
In parallel to the laser head integration and testing, materials and optics qualification and acceptance tests have been performed, e.g. to determine the optical damage threshold or the susceptibility to laser induced contamination processes.
Before delivery to the NASA GSFC for integration to the mass spectrometer (MS) flight model (FM), the laser system has been qualified in an environmental test campaign including vibration, shock and thermal-vacuum testing. After delivery to GSFC and integration to the FM MS, the system has been successfully re-tested on the instrument level.
For the ESA/Roscosmos ExoMars 2020 mission a pulsed UV laser source as part of the Mars Organic Molecule Analyzer (MOMA) instrument was developed, assembled and thoroughly tested concerning thermal, vibrational and shock loads. The characterization was performed before and after integration to a mass spectrometer, which serves as the detector for ionized fragments desorbed from the Martian soil samples due to UV irradiation. The opto-mechanical design of the flight model and the verification of its suitability for the mission requirements are presented here. A longitudinally pumped, passively Q-switched oscillator emits bursts of up to 50 pulses with an output energy of 1.1 mJ at 1064 nm and an intra-burst repetition rate of 100 Hz. Via a two-stage frequency quadrupling with a KTP and a BBO crystal this radiation is converted to 1.5 ns long pulses at 266 nm with an output energy of 130 μJ which can be decreased by temperature tuning of the nonlinear crystals to less than 10% of the nominal energy. The laser head also comprises beam shaping and steering optics to adjust the spot size and position on the sample and the capability to measure the UV energy and the pulse release time. The complex opto-mechanical design is realized within an envelope of less than 220×57×45 mm3 and has a total mass of less than 220 g. To minimize negative effects of the harsh Martian environment on the coatings the laser head is enclosed in a hermetically sealed housing filled with dry synthetic air.
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