Data of the „ROMAP“-Magentometer aids in reconstruction of flight path
Just a little time after Rosetta lander „Philae“ touched down on a comet it was clear that the mission was not continuing as expected, because the lander bounced off the surface. The international team of scientists lead by geophysicist Dr. Uli Auster from the Institut für Geophysik und extraterrestische Physik was working at the „Philae“ control center at that time and followed the incredible flight of the lander.
The data obtained by the ROMAP magnetometer from Braunschweig immediatly showed the signatures of this bouncing and the subsequent touchdowns. With the data, the movement on the comet can be reconstructed.
Bounce: two hours above the comet
In the evening of 12th November, 2014, the scientists around Dr. Hans-Ulrich Auster were surprised when they saw the data of the ROMAP magnetometer immediately after touchdown: „With the magnetometer we can reconstuct the movement of the lander, just like the rotation of a compass needle. Consequently we could see instantly that „Philae“ bounced off the surface and finally returned after two hours. After evaluating our data we now have more information on the path to the final and still unknown landing site“ explained Dr. Auster.
Possible collision with a crater rim
Now the magnetic field data reveals that after the first touchdown „Philae“ started to rotate about its vertical axis, says Auster. The reason was that the reaction wheel, that was stabilizing the lander during descend, transferred its momentum to the freely moving lander. Within 40 minutes Philae accelerated to a rotational velocity of about 5 rpm, which is comparable to a wind turbine at low wind speeds“ says the geophysicist. But after 45 minutes the pattern changed suddenly: „The rotational velocity decreased to half the original speed, the axis tilted and the lander began to tumble. Most likely the reason was a collision with a crater rim“ summarized Dr. Auster.
Second landing decides Philae's fate
The magnetometer from Braunschweig shows that the lander tumbled above the surface for another hour before it jarringly touched down for the second time. „Then the fate of the lander was decided, which was also visible in magnetic field signatures. After first grazing the surface, „Philae“ landed on its feet at the last moment. After another seven minute bounce the lander arrived at its final position surrounded by icy walls“ say Hans-Ulrich Auster. „Although there was some luck involved, the astonishing landing impressively demonstrated that the lander was sturdy enough to not only withstand the harsh environmental conditions of space but also managed to survive this arduous landing sequence.”
The Rosetta Lander Magnetometer and Plasma Monitor (ROMAP) is one of ten instruments on the lander „Philae“, that investigates the magnetic field and solar wind parameters of the comet 67P/Churyumov-Gerasimenko for the ESA Mission Rosetta. Lead by Dr. Hans-Ulrich Auster of the Institut für Geophysik und extraterrestrische Physik at Technische Universität Braunschweig scientists from the Energy Research center in Budapest, the Institut für Weltraumforschung Graz in Austria and the Max-Planck Institut für Sonnensystemforschung in Göttingen contribute.
Dr. Hans-Ulrich Auster
Institut für Geophysik und extraterrestrische Physik
Technische Universität Braunschweig
Tel.: 0531 391-5241
Stephan Nachtigall | idw - Informationsdienst Wissenschaft
'Frequency combs' ID chemicals within the mid-infrared spectral region
16.03.2018 | American Institute of Physics
Fraunhofer HHI have developed a novel single-polarization Kramers-Kronig receiver scheme
16.03.2018 | Fraunhofer-Institut für Nachrichtentechnik, Heinrich-Hertz-Institut, HHI
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.
Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...
16.03.2018 | Event News
13.03.2018 | Event News
08.03.2018 | Event News
16.03.2018 | Earth Sciences
16.03.2018 | Physics and Astronomy
16.03.2018 | Life Sciences