Zitat von Ulrich Elkmann im Beitrag SpX-DM2 und darüber hinaus. Nebst der Beantwortung der Frage: "Wer ist Elon Musk"?18:06: Start. Der Start hat den Europa Clipper zunächst in einen Parkorbit gebracht, um ihn in die Position zu bringen, von der er durch die zweite Zündung auf den Kurs zu den beiden Swingby-Manövern am Mars (27.2.2025) und der Erde (12.1.2026) gebracht werden kann.
2. Start der Falcon Heavy in diesem Jahr, 96. Start für SpaceX. 2023 haben sie insgesamt 96 Starts durchgeführt.
Ich koppel' das mal aus dem "Wer ist Elon Musk"-Strang vom Oktober 2024 aus, weil das gerade eine eigene Abzweigung genommen hat. Der Europa Clipper soll ja nach der Ankunft beim Jupiter am 11. April 2030 die großen, nach bzw. durch Galilei benannten Eismonde näher in Augenschein nehmen und mit seinem Radar Daten aus 10 bis 20 km Tiefe aus der Eisschicht gewinnen (da nach manchen Modellierungen diese Packeispanzer zwischen 50 und 100 km dick sein könnten, könnte das inkonkludent ausfallen). Eine der beständigen Diskussionen seit 40 Jahren rankt sich darum, ob solche Tiefenozeane, die durch den Gezeitenrieb flüssig gehalten werden, Leben entwickelt haben könnten (das erste Auftreten hat in Arthur C. Clarkes "2010", der Fortsetzung zu "A Space Odyssey" von 1982 stattgefunden). Und zufällig stolpere ich gerade über dies hier:
Zitat The deep ocean floor is covered in naturally-occurring batteries that make oxygen... Wait, WHAT?! This has HUGE implications for life on icy moons. Interesting New Paper #3...
A truly extraordinary paper has just been published in Nature Geoscience: “Evidence of dark oxygen production at the abyssal seafloor,” by those doughty warriors for truth (…deep breath… people who put all that work in deserve to have their names mentioned when that work is being discussed… OK, here we go…) Andrew K. Sweetman, Alycia J. Smith, Danielle S. W. de Jonge, Tobias Hahn, Peter Schroedl, Michael Silverstein, Claire Andrade, R. Lawrence Edwards, Alastair J. M. Lough, Clare Woulds, William B. Homoky, Andrea Koschinsky, Sebastian Fuchs, Thomas Kuhn, Franz Geiger & Jeffrey J. Marlow. Phew!
It’s all about polymetallic nodules, so I’d better explain what they are first. ... So, this really is an astounding discovery. The production of oxygen by these manganese and iron and cobalt and nickel nodules seems to be, as far as we can tell so far, the result of a purely chemical reaction. But that purely chemical oxygen production is enabling biological life at these extreme oceanic depths.
Here’s a link to a good report from Science Daily.
And here are the juciest quotes…
"The polymetallic nodules that produce this oxygen contain metals such as cobalt, nickel, copper, lithium and manganese -- which are all critical elements used in batteries," said [Franz] Geiger, who co-authored the study. Geiger is the Charles E. and Emma H. Morrison Professor of Chemistry at Northwestern's Weinberg College of Arts and Sciences and member of the International Institute for Nanotechnology and the Paula M. Trienens Institute for Energy and Sustainability
"When we first got this data, we thought the sensors were faulty because every study ever done in the deep sea has only seen oxygen being consumed rather than produced," [Andrew] Sweetman said. "We would come home and recalibrate the sensors, but, over the course of 10 years, these strange oxygen readings kept showing up.
"We decided to take a back-up method that worked differently to the optode sensors we were using. When both methods came back with the same result, we knew we were onto something ground-breaking and unthought-of."
To investigate this hypothesis, Sweetman shipped several pounds of the polymetallic nodules, which were collected from the ocean floor, to Geiger's laboratory at Northwestern. Sweetman also visited Northwestern last December, spending a week in Geiger's lab.
Just 1.5 volts -- the same voltage as a typical AA battery -- is enough to split seawater. Amazingly, the team recorded voltages of up to 0.95 volts on the surface of single nodules. And when multiple nodules clustered together, the voltage can be much more significant, just like when batteries are connected in a series.
"It appears that we discovered a natural 'geobattery,'" Geiger said. "These geobatteries are the basis for a possible explanation of the ocean's dark oxygen production." –Science Daily. (Materials provided by Northwestern University. Original written by Amanda Morris.)
This is a beautiful example of something that we're going to see again and again, when we examine the totality of a planet like Earth, and treat it as an evolved system: the geosphere actively enables the biosphere. They are inextricably entwined. In particular, inorganic chemistry complexifies over time in such a way as to create the conditions for organic chemistry. Put more simply, rock chemistry generates the conditions for egg chemistry.
The deep sea has lungs. They produce enough oxygen for life to flourish, and they do it without sunlight, in deep water, purely chemically. Sure, most of the oxygen down there still comes from biological activity miles above, dissolved into the shallow surface waters, and carried into the depths as it cools and falls. But hey, this new source is a radical discovery.
The implications for life in the liquid water oceans, under the surface of icy moons, are obvious, and enormous. So I'm going to predict now, with medium confidence (and a couple of caveats, to follow) that we may well ultimately discover similar polymetallic nodules, producing oxygen through similar chemical processes, on the warm seafloors of the liquid water oceans under the frozen crusts of icy moons.
The same sea floor volcanic vents that melt the ice to make those liquid water oceans will also provide the manganese, iron, cobalt, nickel, et cetera, that these nodules require.
Obviously, this requires the icy moons to have rocky cores with a fairly high degree of manganese, iron, nickel, and cobalt content. (OK, maybe not much cobalt.) I think this will turn out to be the case for a high percentage of icy moons.
As I'm arguing in a series of posts, I think liquid water oceans on icy moons will turn out to be the commonest homes for life in this universe. And the biosphere in such oceans would have to be powered, not by sunlight, but by the gravitational energy of the planet tugging on the moon’s core, thus keeping it molten. Which is great, but… those liquid water oceans are under a mile or two of solid ice, incredibly far from the sun. Zero sunlight down there. No photosynthesis...
So polymetallic nodules could potentially solve the oxygen problem, performing the function photosynthetic plants do on Earth.
Zitat NASA Europa Clipper@EuropaClipper Our spacecraft is currently inbound for Mars! No, we're not lost – on March 1 we'll perform a gravity assist maneuver, using the Red Planet to help shape our trajectory out to Jupiter and its ocean moon Europa. https://go.nasa.gov/4bfYfba 8:15 PM · Feb 25, 2025
Zitat On March 1, NASA’s Europa Clipper will streak just 550 miles (884 kilometers) above the surface of Mars for what’s known as a gravity assist — a maneuver to bend the spacecraft’s trajectory and position it for a critical leg of its long voyage to the Jupiter system. The close flyby offers a bonus opportunity for mission scientists, who will test their radar instrument and thermal imager.
Europa Clipper will be closest to the Red Planet at 12:57 p.m. EST, approaching it at about 15.2 miles per second (24.5 kilometers per second) relative to the Sun. For about 12 hours prior and 12 hours after that time, the spacecraft will use the gravitational pull of Mars to pump the brakes and reshape its orbit around the Sun. As the orbiter leaves Mars behind, it will be traveling at a speed of about 14 miles per second (22.5 kilometers per second).
The flyby sets up Europa Clipper for its second gravity assist — a close encounter with Earth in December 2026 that will act as a slingshot and give the spacecraft a velocity boost. After that, it’s a straightforward trek to the outer solar system; the probe is set to arrive at Jupiter’s orbit in April 2030.
Navigators sent the spacecraft on an initial trajectory that left some buffer around Mars so that if anything were to go wrong in the weeks after launch, Europa Clipper wouldn’t risk impacting the planet. Then the team used the spacecraft’s engines to veer closer to Mars’ orbit in what are called trajectory correction maneuvers, or TCMs.
Mission controllers have performed three TCMs to set the stage for the Mars gravity assist — in early November, late January, and on Feb. 14. They will conduct another TCM about 15 days after the Mars flyby to ensure the spacecraft is on track and are likely to conduct additional ones — upwards of 200 — throughout the mission, which is set to last until 2034.
Zitat NASA Solar System@NASASolarSystem Getting into the thick of it: Data from our #JunoMission has provided new insights into the thickness and subsurface structure of the icy shell encasing Jupiter’s moon Europa and its global ocean of water. https://go.nasa.gov/4aef87f 10:47 PM · Jan 27, 2026
Zitat NASA’s Juno Measures Thickness of Europa’s Ice Shell
Data from NASA’s Juno mission has provided new insights into the thickness and subsurface structure of the icy shell encasing Jupiter’s moon Europa. Using the spacecraft’s Microwave Radiometer (MWR), mission scientists determined that the shell averages about 18 miles (29 kilometers) thick in the region observed during Juno’s 2022 flyby of Europa. The Juno measurement is the first to discriminate between thin and thick shell models that have suggested the ice shell is anywhere from less than half a mile to tens of miles thick.
Slightly smaller than Earth’s moon, Europa is one of the solar system’s highest-priority science targets for investigating habitability. Evidence suggests that the ingredients for life may exist in the saltwater ocean that lies beneath its ice shell. Uncovering a variety of characteristics of the ice shell, including its thickness, provides crucial pieces of the puzzle for understanding the moon’s internal workings and the potential for the existence of a habitable environment.
The new estimate on the ice thickness in the near-surface icy crust was published on Dec. 17 in the journal Nature Astronomy.
Jupiter’s moon Europa is thought to harbour a saltwater ocean beneath a variously disrupted ice shell, and it is, thus, one of the highest priority astrobiology targets in the Solar System. Estimates of the ice-shell thickness range from 3 km to over 30 km, and observations by the Galileo spacecraft indicated widespread regions of ice disruption (chaotic terrain) leading to speculation that the ice shell may contain subsurface cracks, faults, pores or bubbles. If persistent, subsurface cracks could provide pathways for habitability by facilitating the transport of oxygen and nutrients between the surface and the ocean. Here we report on observations of Europa’s subsurface ice shell obtained by the Juno microwave radiometer in 2022. For the idealized case of pure water ice, the data are consistent with the existence of a thermally conductive ice shell with a thickness of 29 ± 10 km and with the presence of cracks, pores or other scatterers extending to depths of hundreds of metres below the surface with a characteristic size smaller than a few centimetres in radius. An ice-shell salinity of 15 mg kg−1, as indicated by models based on terrestrial marine ice, would reduce our estimate of the thickness of the ice shell by about 5 km, substantially less than our 10 km uncertainty. The low volume fraction, small size and shallow depth of the scatterers indicate that the fracture interfaces observed at Europa’s surface are alone unlikely to be capable of carrying nutrients between the surface and the ocean.
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