Jezero is not just any impact crater on Mars. An old river delta near the western rim of the crater testifies that it once housed a lake. Numerous aqueous minerals prove that liquid water must have been present in it for a very long time - one of the most important prerequisites for life. This is why Jezero is also the target of the current NASA mission Mars 2020, which will start on 30 July 2020 at 13.50 CEST and in February 2021 will begin its search for
traces of life will begin in the former crater lake.

Jezero is located on the north-western edge of Isidis Planitia, one of the largest impact basins on Mars. In its immediate vicinity, some of the oldest and most interesting geological formations and rocks on Mars can be found. The area shown here is about 18 degrees latitude and 77 degrees longitude north of the Mars equator.

Small flight guide
When approaching the crater Jezero, one first flies over the outflow channel from the east, from which the water from the lake flowed out again. Then one reaches a yellow ellipse that marks the landing site region, which measures about 10 kilometres, where the Mars 2020 rover Perseverance ("Persistence") will be set down in February 2021 with a sky crane, similar to the predecessor rover Curiosity. The ellipse partially covers the river delta, which geomorphologists refer to as the "bird foot delta" because its broad "arms" resemble the foot of a bird. Through the meandering valley Neretva Vallis, which breaks through the Karterand from the west, a river flowed until about 3.8 billion years ago, whose carried sediments formed the delta. The crater itself is now very shallow because it has been heavily backfilled by lake sediments and material brought in by the wind. Its crater rim today only rises about a thousand mater above its bottom.

The crater has a diameter of about 45 kilometres and its heavily eroded rim is penetrated in the west and east by an inflow and outflow channel respectively. Such lakes are called "open basin lakes", which means that water continuously flows in and out of them. They are also fed mainly by surface water.

The sediments transported by the western tributary created a river delta whose mineralogical composition attracted the attention of the scientists: It consists not only, as so often elsewhere on Mars, of clay minerals rich in aluminium and iron and magnesium, which were formed by the chemical weathering of the source rock in the presence of liquid water. It also contains carbonate minerals that are common on Earth in limestone or dolomite and could actually have been formed in the lake itself. The interesting thing about these carbonate minerals formed in the lake is that they are particularly capable of preserving macro- and microscopic biosignatures, i.e. organic molecules or even fossil microorganisms, over billions of years.

 

The NASA mission Mars 2020 will use intensive and complex chemical investigations and sampling to investigate whether life once originated in this crater lake. In addition, 43 rock and soil samples will be deposited in containers that are to be brought back to earth by the early 2030s for precise analysis.

The digital terrain model of the stereo camera HRSC on which the film is based has made an important contribution to the exploration and selection of this landing site. It was created at DLR and Freie Universität Berlin at the request of the Mars 2020 project and evaluated together with the Jet Propulsion Laboratory (JPL) for the landing site selection and for the development of the navigation systems for the landing. But geological questions can also be answered with such precise data from the German stereo camera. In addition to the depth and volume of the crater lake, it is also possible, for example, to estimate the water flow of the rivers. For this purpose, the width, depth and gradient of the respective riverbed are related to the properties of the underlying rock. Precise, high-resolution topographical data from the HRSC, calculated by scientists from DLR and Freie Universität Berlin and made available to NASA and ESA, were and are indispensable for the selection of landing sites for earlier (Spirit, Opportunity, Phoenix), current (Curiosity, InSight) and Mars missions that will be launched in 2020 and 2022 and land seven months later (Mars 2020/Perseverance and ExoMars/Rosalind Franklin).


ESA is currently examining whether the Mars Express mission, which has already lasted for more than 16 years and on which the HRSC camera is flying, must and should be extended for the eighth time.

Copyrights

Film: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Music: Björn Schreiner

Soundtrack Logo: Alicia Neesemann

Copyright Notice:

The video is licenced under the Creative Commons Attribution-ShareAlike 3.0 IGO (CC BY-SA 3.0 IGO) licence. The user is allowed to reproduce, distribute, adapt, translate and publicly perform it, without explicit permission, provided that the content is accompanied by an acknowledgement that the source is credited as 'ESA/DLR/FU Berlin', a direct link to the licence text is provided and that it is clearly indicated if changes were made to the original content. Adaptation / translation / derivatives must be distributed under the same licence terms as this publication.

The High Resolution Stereo Camera was developed at the German Aerospace Center (DLR) and built in collaboration with partners in industry (EADS Astrium, Lewicki Microelectronic GmbH and Jena-Optronik GmbH). The science team, which is headed by Principal Investigator (PI) Ralf Jaumann, consists of 52 co-investigators from 34 institutions and 11 countries. The camera is operated by the DLR Institute of Planetary Research in Berlin-Adlershof.