University of Bern’s Laser Altimeter BELA has been successfully tested during the last weeks and the last components will be delivered to ESA on 5 October. The first laser altimeter for inter-planetary flight to be built in Europe is part of the ESA BepiColombo mission to Mercury. Starting in 2024, it will provide data about the planet’s surface.
BELA (BepiColombo Laser Altimeter) has been developed by a Swiss-German-Spanish team led by the University of Bern. The instrument is designed to measure the topography of the planet Mercury, from onboard ESA’s space mission, BepiColombo, which is due to launch in April 2018. After an over 80 million kilometer journey, BepiColombo will go into orbit around Mercury in 2024.
Entering the third dimension
«Cameras give us a 2D picture of planet. BELA is designed to give us the third dimension», says Nicolas Thomas, co-Principal Investigator and the hardware leader of the project. BELA uses a high power laser to determine the distance from the spacecraft to the surface of Mercury. Short pulses from an infrared laser are fired at the planet.
The light is reflected from the planet’s surface back to a Swiss-designed ultra-lightweight telescope and the time of flight of the laser pulse is measured. This approach allows BELA to measure the topography of mercury to an accuracy of better than one meter from a distance of 1000 kilometers. Nicolas Thomas puts it more pictorially: «It is a bit like measuring the distance to the North face of the Eiger to one meter accuracy from Hamburg».
«Together with our industrial partners in Switzerland, Germany, and Spain, we have developed a really advanced piece of equipment», says Karsten Seiferlin, the BELA Project Manager. «On Earth, rangefinders are common these days, but putting one in space to range over distances of over 1000 kilometers and weighing under 14 kilograms is extremely challenging.»
The returned pulse is only a few hundred photons, requiring a sophisticated detection scheme. Constructing such a scheme was especially difficult because Mercury is the nearest planet to the Sun and so the team also had to worry about the temperatures which reach around 200 degrees Celsius on the spacecraft outer skin.
However, the huge power consumption of the laser in a very short time ended up being the biggest problem. «This produces noise on the electrical signals. We had to far exceed the requirements normally used for space instruments for grounding the electronics», Nicolas Thomas explains.
Inspired by Albert Einstein
«The electronics for BELA required six different organizations to work together. We ended up having to develop several, very new, technical solutions to make the experiment work», says Thomas. «But BELA will contribute a lot to understanding Mercury. Einstein’s studies of the motion of Mercury have been so important to the theory of general relativity. It is nice to think that with this instrument, the University of Bern, where he used to work, can play a leading role in studying this particular planet in detail.»
The BepiColombo mission comprises two spacecraft, the Mercury Planetary Orbiter (MPO) to be built by ESA and the Mercury Magnetospheric Orbiter (MMO) to be built by JAXA. The two spacecraft will fly to Mercury together in a coupled system until reaching Mercury orbit. The MMO will then be released into a 400 km x 19200 km orbit to allow detailed study of the magnetospheric interaction between the planet and the solar wind. The MPO will then descend to a 400 km x 1500 km orbit which is optimum for remote-sensing of the planet's surface.
Prof. Dr. Nicolas Thomas
Center for Space and Habitability, University of Bern
Phone +41 31 631 44 06 / firstname.lastname@example.org
Nathalie Matter | Universität Bern
A new force for optical tweezers awakens
19.06.2019 | University of Gothenburg
View of the Earth in front of the Sun
19.06.2019 | Georg-August-Universität Göttingen
The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.
Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...
The well-known representation of chemical elements is just one example of how objects can be arranged and classified
The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...
Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.
Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...
Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.
The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...
Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.
The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
19.06.2019 | Physics and Astronomy
19.06.2019 | Information Technology
19.06.2019 | Materials Sciences