@AkaSci@fosstodon.org
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AkaSci

@AkaSci@fosstodon.org

SatCom Scientist
Writing occasionally about space missions, astronomy, planetary science, satellites and science in general.
He/Him
#science #space #technology #astronomy #satellites #Democracy

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AkaSci, to random
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The Vault Plate of the Europa Clipper spacecraft has been mounted.

The plate carries inspirational messages from Earth for posterity, such as -

  • Ada Limón’s poem “In Praise of Mystery: A Poem for Europa”
  • A microchip with over 2.6 million names
  • The Drake Equation
  • "Water Words" — a visual representation of the word for water in 103 spoken languages (seen below)

Check out this earlier thread for more info on the plate -
https://fosstodon.org/@AkaSci/112066301959239593

Next - travel to FL for launch in Oct.

1/n

AkaSci, (edited )
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We can see the chip that contains the 2.6 million names mounted on the backside of the Europa Clipper Vault Plate in the pic below, placed inside the image of the bottle.

Is your name in it, to be read by some future visitor to Europa?

2/n

AkaSci,
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@AthanSpod
A little disoriented this morning
Thanks for pointing it out.

AkaSci, to random
@AkaSci@fosstodon.org avatar

Happy Birthday to Audrey Hepburn.

Besides her fabulous and memorable film career, Hepburn also worked in some of the poorest communities of Africa, South America and Asia. In December 1992, Hepburn received the US Presidential Medal of Freedom in recognition of her work as a UNICEF Goodwill Ambassador.

How do you remember her?

https://www.youtube.com/watch?v=kySu0TGPe5I
1/n

AkaSci, (edited ) to random
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May the 4th with you be.
Happy
1/n

AkaSci,
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Mark Hamill: "May The Fourth Be The Day A Make-Believe Defender Of The Galaxy Met A Real-Life Defender Of Democracy"

Earlier Tweets by Mark Hamill:
"May The Third Be Absurd That The Guy Who Tried To Steal A Fair Election Is Allowed To Run Again"

"May The Second Biden Administration Be As Productive and Successful As The 1st"

"May The First Not Quench Your Thirst For Biden’s Re-election!"


2/n

AkaSci,
@AkaSci@fosstodon.org avatar

May the Fourth be with You.
John Williams & Wiener Philharmoniker – "Main Title" from "Star Wars: A New Hope"

https://youtu.be/54hoKbTWon4


3/n

AkaSci,
@AkaSci@fosstodon.org avatar

May the Fourth be with You 🔦

The Imperial March played by the Vienna Philharmonic Orchestra, during the Summernight Concert at Schönbrunn on June 8, 2010.

https://youtu.be/HDIsiSJjnL4
4/n

AkaSci,
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Kepler-16b, an exoplanet orbiting a binary star, sees two Suns just like the fictional planet Tatooine, home planet of Luke Skywalker and of his father, Anakin Skywalker (Darth Vader).

Tatooine was a sparsely inhabited desert planet orbiting two scorching suns. Lacking surface water, many residents of the planet drew water from the atmosphere via moisture farms.

https://exoplanets.nasa.gov/alien-worlds/exoplanet-travel-bureau/explore-kepler-16b/
5/n

AkaSci,
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Tatooine, home planet of Luke Skywalker, with its two Suns and its moisture farms.

https://youtu.be/sFGqlRoZFh8
6/n

AkaSci, (edited ) to random
@AkaSci@fosstodon.org avatar

China's Chang'e 6 mission to the moon was launched today.

The spacecraft and mission are very similar to Chang'e 5, which brought lunar rock samples back to earth in 2020, except that the Chang'e 6 landing site is on the far side of the moon (43.0°S 154.0°W).

Comms will take place via the Queqiao-2 relay satellite, which was launched on March 20 and is in an elliptical lunar orbit of 200×16,000 km at 62.4° inclination.

Mission time: 53 days

https://www.youtube.com/watch?v=R7a4n-rmBIw
https://en.wikipedia.org/wiki/Chang%27e_6
1/n

AkaSci, (edited )
@AkaSci@fosstodon.org avatar

Chang'e 6 will land on and bring back lunar samples from the far side of the moon at location 43.0°S 154.0°W, near the southern edge of the Apollo crater.

There is interest in exploring this south polar region due to the possibility of water ice. Also, the region could contain material ejected from the lunar mantle, which can provide insights into the history of the Earth-moon system.

https://quickmap.lroc.asu.edu/?camera=-3013276.935%2C-1179845.963%2C-4427716.696%2C0.002%2C-1.530%2C0.000%2C5484209.106%2C60.000&id=lroc&showGraticule=true&showTerrain=true&queryOpts=N4XyA&isCesiumEntityDetailsEnabled=true&showCompass=true&trailType=1&wideTrail=true&layers=NrBsFYBoAZIRnpEBmZcAsjYIHYFcAbAyAbwF8BdC0ypcOKbRFOOZRBaAOnXfyJpVBFIA&proj=22
2/n

AkaSci, (edited )
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Similar to Chang'e 5, the Chang'e 6 spacecraft consists of 4 main modules - the Service Module, the Return Vehicle, the Lander and the Ascent Vehicle.

The lander includes a coring drill and a robotic arm to collect samples.

There is no rover, although the mission carries a few other instruments.

The solar powered lander has to finish its mission in 14 earth-days.

https://en.wikipedia.org/wiki/Chang%27e_6
https://spj.science.org/doi/10.34133/2021/9823609
https://www.sciencedirect.com/science/article/pii/S1000936122000231
3/n

AkaSci,
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Here is a detailed animation of the Chang'e 5 sample return mission to the moon. It shows the various steps and complex choreography of the mission including launch, orbit insertion, landing, sample collection, ascent, transfer of samples, return to earth and landing of sample capsule.

The Chang'e 6 spacecraft hardware and mission procedures are very similar, except for the landing location on the far side of the moon and the use of the Queqiao-2 relay satellite.

https://www.youtube.com/watch?v=xMet268iaKc
4/n

AkaSci,
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Let's send our best wishes for the success of the ambitious Chang'e 6 sample return mission to the far side of the moon.

Robotic landing on the moon has turned out to be lot harder than we thought, as evident from the poor success rate in such missions over the past few years. See table below.
🤞
5/n

AkaSci, (edited )
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The Chang'e 6 mission is expected to return lunar samples to earth 53 days after launch.

The lander is powered by solar cells (not an RTG as used by Chang'e 4 which also landed on the far side of the moon). Hence, it is expected to complete its surface mission during the lunar day. We can expect the landing to occur around May 29, since the Sun will rise at the landing site around then, as shown in the graph below of the elevation angle of the Sun at the site.

https://spectrum.ieee.org/china-moon-landing-uncrewed-chang-e6
6/n

AkaSci, (edited ) to random
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Here is a fascinating video of the coating of the 8.4-meter primary/tertiary mirror of the Rubin Observatory, performed on April 27, onsite in Cerro Pachón, Chile.

Using a technique called magnetron sputtering, 4 coats were applied -

  1. An adhesion layer of nickel-chromium (NiCr)
  2. The reflective layer of silver (Ag)
  3. Another NiCr adhesion layer
  4. A protective layer of silicon nitride (Si3N4)

Looking good!

https://www.youtube.com/watch?v=yKqEDFvmYwY
https://noirlab.edu/public/news/noirlab2411/
1/n

AkaSci,
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Here is an aerial view of the Rubin Observatory site in the scenic mountains of Cerro Pachón, Chile.

First light for the engineering camera is expected in August 2024, while system first light is expected in January 2025, Full survey operations are aimed to begin in August 2025.

https://noirlab.edu/public/images/noirlab2411b/
https://rubinobservatory.org/
2/n

AkaSci, (edited )
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The Rubin Observatory Simonyi Survey Telescope consists of 3 aspheric mirrors: an 8.4-m primary mirror M1, a 3.5-m convex secondary mirror M2, and a 5.0-m tertiary mirror M3.

The primary and tertiary mirrors, which were coated on April 27, are fabricated from a single piece of glass.
The secondary mirror (M2) is the largest convex mirror ever made.
Field of view = 3.5°.
The 3.2-gigapixel camera hangs below the secondary mirror.
https://www.lsst.org/about/tel-site/optical_design

3/n

AkaSci,
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@Pyrrhlin @ISibboI
Also, in this case, the field of view is very large, which makes it challenging to create a telescope that can remove all the optical aberrations introduced by mirrors.
It require mirrors with a very large focal length - folding the path 3 times helps on that front. Also I think the 3 mirrors help remove aberrations better than 2.

AkaSci, (edited ) to random
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Vitamin D alters mouse gut bacteria to give better cancer immunity

"... mice with increased availability of vitamin D display greater immune-dependent resistance to transplantable cancers and augmented responses to checkpoint blockade immunotherapies.

Similarly, in humans, vitamin D–induced genes correlate with improved responses to immune checkpoint inhibitor treatment as well as with immunity to cancer and increased overall survival."
🤔

https://www.science.org/doi/10.1126/science.adh7954?utm_campaign=SciMag
https://twitter.com/giampazolias/status/1783737819959366124

AkaSci, (edited ) to random
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Behold this new hi-res (false-color) image of the "mane" of the Horsehead Nebula taken by JWST's NIRCam Camera.

The Nebula, 1300 light years away, was formed from a collapsing interstellar cloud of material and is illuminated by a nearby star.

The region with the blue clouds contains cold, molecular hydrogen, not yet eroded by UV light from nearby stars. The red photodissociation region contains atomic hydrogen gas and dust, above which lies ionized gas.

https://science.nasa.gov/missions/webb/webb-captures-top-of-iconic-horsehead-nebula-in-unprecedented-detail/
1/n

AkaSci,
@AkaSci@fosstodon.org avatar

@hendric
Multiple JWST instruments can be operated at the same time for a given observation, depending on the nature of the experiment. Typically, I think it is two instruments that are used concurrently.

AkaSci,
@AkaSci@fosstodon.org avatar

One more beautiful pic of the Horsehead Nebula along with the colorful Flame Nebula. This one was featured on APOD in 2021.

Image Credit & Copyright: Wissam Ayoub
https://apod.nasa.gov/apod/ap211103.html
8/n

AkaSci,
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Zooming out, one can see the massive region called the “Orion B Molecular Cloud”, surrounding the Horsehead Nebula and the Flame Nebula. In the dense filaments of gas and dust, the orange and yellow clumps represent the earliest stages of star formation, with green and blue regions representing warmer dust heated by stars that have already formed.

This image was taken by the Herschel space telescope in 2013 in far-infrared wavelengths from 70 to 250 µm.

https://herscheltelescope.org.uk/results/horsehead-nebula/
9/n

AkaSci, to random
@AkaSci@fosstodon.org avatar

Happy Birthday to the Hubble Space Telescope, launched OTD in 1990, with Space Shuttle Discovery during the STS-31 mission.

34 years and 5 servicing missions later, Hubble is still going strong, unfolding the mysteries of the Universe from its perch 540 km above earth.

https://www.flickr.com/photos/nasahubble/albums/72157670398668526/
https://hubblesite.org/home
1/n

AkaSci,
@AkaSci@fosstodon.org avatar

Some welcome news from the Hubble team.

The team successfully restored HST to science operations yesterday April 29. HST is now operating with all 3 gyros; all instruments and computer systems are online and in good health.

The blog post does not specify the nature of the problem with the ailing gyro or the fix. The spacecraft had entered safe-mode on April 23 when one of the 3 healthy gyros started giving faulty readings.

https://science.nasa.gov/missions/hubble/nasas-hubble-pauses-science-due-to-gyro-issue/
5/n

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