Zitat von 28/04/2023Juice’s ice-penetrating RIME antenna has not yet been deployed as planned. During the first week of commissioning, an issue arose with the 16-metre-long Radar for Icy Moons Exploration (RIME) antenna, which is preventing it from being released from its mounting bracket.
Work continues to free the radar and teams at ESA’s mission control centre in Darmstadt, Germany, along with partners in science and industry, have lots of ideas up their sleeves.
Every day the RIME antenna shows more signs of movement, visible in images from the Juice Monitoring Camera on board the spacecraft with a partial view of the radar and its mount. Now partially extended but still stowed away, the radar is roughly a third of its full intended length.
The current leading hypothesis is that a tiny stuck pin has not yet made way for the antenna’s release. In this case, it is thought that just a matter of millimetres could make the difference to set the rest of the radar free.
Various options are still available to nudge the important instrument out of its current position. The next steps to fully deploy the antenna include an engine burn to shake the spacecraft a little followed by a series of rotations that will turn Juice, warming up the mount and radar, which are currently in the cold shadows.
Juice is otherwise performing excellently after the successful deployment and operation of its mission-critical solar arrays and medium gain antenna, as well as its 10.6-m magnetometer boom.
With two months of planned commissioning remaining, there is plenty of time for teams to get to the bottom of the RIME deployment issue and continue work on the rest of the powerful suite of instruments on their way to investigate the outer Solar System.
Last week we commissioned @ESA_Juice’s attitude control thrusters and the large 400-newton main engine that'll be used for big orbital manoeuvres.
Now the 'big guns' are ready we can really get things shaking, in the hope of unjamming the stuck RIME antenna📡🤝 3:08 PM · May 3, 2023
'Shake-ups' will be combined with slews (rotations) that'll turn the spacecraft and get the stubborn mounting bracket - currently in the cold shadows - into the light and warmed up. Slews begin tomorrow. 3:09 PM · May 3, 2023
Zitat Marcia Smith @SpcPlcyOnline At Outer Planets Assessment Group, ESA's Olivier Witasse, Jupiter Icy Moons Explorer (JUICE) proj sci, says not to expect news until end of next wk of whether attempt to unstick Radar for Icy Moons Expl (RIME) worked. Combo of thruster firings and thermal slews to warm it up.
Witasse also said Ariane 5 put JUICE on such a precise trajectory they haven't had to use any of their prop margin and now can "dream" about an extended mission. 7:42 PM · May 3, 2023
Wenn es sich um eine Sonde aus dem ersten Marsorbiterprogramm handel würde, könnte ich mir ja den Kalauer "the RIME of the ancient Mariner" niicht verkneifen...
Zitat ESA Operations @esaoperations·May 9 🚨Another RIME update!🚨
The antenna continues to move in its mounting bracket as teams at ESA #MissionControl pulse Juice's large main engine. No full deployment (yet).
ESA Operations @esaoperations·May 9 Next steps: three more thermal rotations + thruster burns this week. During the third, the remaining 'actuator' (mechanical device to release the other boom) will be fired on the jammed bracket, creating a mechanical shock we hope might free the RIME. 3:53 PM · May 9, 2023
Zitat More than three weeks after efforts began to deploy Juice’s ice-penetrating Radar for Icy Moons Exploration (RIME) antenna, the 16-metre-long boom has finally escaped its mounting bracket. During the first attempt to extend the folded-up antenna, only the first segments of each half were deployed. Flight controllers suspected that a tiny stuck pin jammed the other segments in place. Fortunately, the flight control teams at ESA’s mission control centre in Darmstadt had lots of ideas up their sleeves. To try to shift the pin, they shook Juice using its thrusters, then they warmed Juice with sunlight. Every day the RIME antenna was showing signs of movement, but no full release. On 12 May RIME was finally jolted into life when the flight control team fired a mechanical device called a ‘non-explosive actuator’ (NEA), located in the jammed bracket. This delivered a shock that moved the pin by a matter of millimetres and allowed the antenna to unfold.
Es handelt sich zwar nicht um Jupiter, sondern um die Umgebung des Saturn. Aber weil es um "Ozeane + Leben" geht, paßt das hierher.
Zitat von June 14, 2023NASA Cassini Data Reveals Building Block for Life in Enceladus’ Ocean
Using data collected by NASA’s Cassini mission, an international team of scientists has discovered phosphorus – an essential chemical element for life – locked inside salt-rich ice grains ejected into space from Enceladus.
The small moon is known to possess a subsurface ocean, and water from that ocean erupts through cracks in Enceladus’ icy crust as geysers at its south pole, creating a plume. The plume then feeds Saturn’s E ring (a faint ring outside of the brighter main rings) with icy particles.
During its mission at the gas giant from 2004 to 2017, Cassini flew through the plume and E ring numerous times. Scientists found that Enceladus’ ice grains contain a rich array of minerals and organic compounds – including the ingredients for amino acids – associated with life as we know it.
Phosphorus, the least abundant of the essential elements necessary for biological processes, hadn’t been detected until now. The element is a building block for DNA, which forms chromosomes and carries genetic information, and is present in the bones of mammals, cell membranes, and ocean-dwelling plankton. Phosphorus is also a fundamental part of energy-carrying molecules present in all life on Earth. Life wouldn’t be possible without it.
“We previously found that Enceladus’ ocean is rich in a variety of organic compounds,” said Frank Postberg, a planetary scientist at Freie Universität Berlin, Germany, who led the new study, published on Wednesday, June 14, in the journal Nature. “But now, this new result reveals the clear chemical signature of substantial amounts of phosphorus salts inside icy particles ejected into space by the small moon’s plume. It’s the first time this essential element has been discovered in an ocean beyond Earth.”
Previous analysis of Enceladus’ ice grains revealed concentrations of sodium, potassium, chlorine, and carbonate-containing compounds, and computer modeling suggested the subsurface ocean is of moderate alkalinity – all factors that favor habitable conditions.
For this latest study, the authors accessed the data through NASA’s Planetary Data System, a long-term archive of digital data products returned from the agency’s planetary missions. The archive is actively managed by planetary scientists to help ensure its usefulness and usability by the worldwide planetary science community.
The authors focused on data collected by Cassini’s Cosmic Dust Analyzer instrument when it sampled icy particles from Enceladus in Saturn’s E ring. Many more ice particles were analyzed when Cassini flew through the E ring than when it went through just the plume, so the scientists were able to examine a much larger number of compositional signals there. By doing this, they discovered high concentrations of sodium phosphates – molecules of chemically bound sodium, oxygen, hydrogen, and phosphorus – inside some of those grains.
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