Happy Birthday to Émilie Du Châtelet (Dec 17, 1706 - Sep 10, 1749), French natural philosopher, mathematician and physicist.

A fierce advocate of women's education, Du Châtelet wrote -

“If I were king, I would redress an abuse which cuts back, as it were, one half of human kind. I would have women participate in all human rights, especially those of the mind.
This new system of education that I propose would in all respects be beneficial to the human species ..."

https://www.google.com/books/edition/Selected_Philosophical_and_Scientific_Wr/TgDSoGgR5YMC?hl=en&gbpv=1
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The Voyager spacecraft - takes a licking and keeps on ticking 💪

Voyager 1 seems to have made a full recovery from its recent power-surge caused illness. It is now communicating at it normal data rate of 160 bps using its X-band transmitter.

:mastodance:

https://eyes.nasa.gov/apps/dsn-now/dsn.html
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NASA Deep Space Network (DSN) 70m antenna 63 in Madrid is currently receiving the S-band signal from Voyager 1.

https://eyes.nasa.gov/apps/dsn-now/dsn.html
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Voyager 1 sequence of events contd -

Oct 19 – Signal lost again; team suspected that Voyager fault protection system was triggered twice more and may have switched to a lower power S-band mode, not used since 1981
Oct 19 – 3 antennas at DSN Canberra in array mode detected the faint S-band signal
Oct 22 – Signal sent to validate S-band transmission
Now analyzing data to diagnose and fix the problem and return to X-band mode.

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The aging power-challenged Voyager 1 spacecraft suffered another glitch 2 weeks ago – it stopped calling home on its regular channel. Here is the sequence of events that transpired -

Oct 16 – Command sent to turn on a heater
Oct 18 – X-band signal lost; team surmised that the power-overload triggered the fault protection system and Voyager switched to a low-rate low-power X-band mode
Oct 18 – DSN looked for lower-rate X-band signal and found it
(contd)

https://blogs.nasa.gov/voyager/2024/10/28/after-pause-nasas-voyager-1-communicating-with-mission-team/
#Voyager
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Three weeks after Voyager 1 autonomously flipped over to using the S-band transmitter for communicating with earth because of a power overload condition, it appears that it is back to communicating using X-band.

No word from NASA, but presumably the team managed to turn off the heater that caused the power surge and re-enable the X-band transmitter.

Phew 😓

https://eyes.nasa.gov/apps/dsn-now/dsn.html
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Let's take a moment to marvel at the design of the Voyager spacecraft software - written in assembly language for a custom 1970s CPU, in less than 70 KB of RAM, able to react to failures and keep comms. up.

Possibly, NASA may have to turn off one more instrument on Voyager 1. Over the 47 years since launch, Voyager instruments have gradually been shut off as power levels have declined by over 50%.

But the Voyagers continue to boldly go where no spacecraft has gone before.
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Happy Birthday to C. V. Raman.

Raman was born OTD on Nov 7, 1888 in Tiruchirapalli, British India.

Raman was awarded the 1930 Nobel Prize in Physics for his discovery of Raman scattering.

Raman scattering is the inelastic scattering of photons by matter, where the scattered photons have lower energy (frequency) than the incident ones due to energy absorption by molecules.

#Raman
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NASA Voyager update - on Sept 26, one more instrument aboard Voyager 2 was turned off to conserve power - the plasma science instrument.

Over the 46 years since launch, Voyager instruments have gradually been shut off as power levels have declined by over 50%. With 4 science instruments left, the Voyagers will continue to boldly go where no spacecraft has gone before.

Note that the plasma science instrument on Voyager 1 failed and was turned off in 2007.

https://blogs.nasa.gov/voyager/2024/10/01/nasa-turns-off-science-instrument-to-save-voyager-2-power/
#Voyager
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While we were not watching, the Voyager 1 spacecraft underwent another surgery.

In August, V1 switched thrusters used for orientation control, because the fuel tubes in the thrusters had clogged up with residue.

To perform the switch, the thrusters had to be warmed by turning on its heaters while turning off another set for an hour.

All very tricky and risky operations, performed from 22.8 light-hours away on 1970’s era hardware.

Kudos again to the Voyager team.

https://blogs.nasa.gov/voyager/2024/09/10/voyager-1-team-accomplishes-tricky-thruster-swap/
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Happy Birthday to Marie Tharp (July 30, 1920 – August 23, 2006), American geologist and oceanographic cartographer extraordinaire.

She built the first accurate map of the Atlantic Ocean floor and discovered the Mid-Atlantic Ridge that led to the acceptance of the theories of plate tectonics and continental drift.

https://web.whoi.edu/womens-comm/marie-tharp-pioneering-mapmaker-of-the-ocean-floor/
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The Internet is buzzing with reports of Mars rover Perseverance finding possible signs of ancient microbial life.

Analysis of the rock named “Cheyava Falls” by Perseverance's instruments indicate chemical signatures and structures that could have been formed by microbial life billions of years ago when the area had running water. But non-biological origins cannot be ruled out.

Only bringing the rock back to earth will provide definitive answers.

https://www.nasa.gov/missions/mars-2020-perseverance/perseverance-rover/nasas-perseverance-rover-scientists-find-intriguing-mars-rock/
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Happy Birthday to American astronomer Henrietta Swan Leavitt (born July 4, 1868, Lancaster, MA, died Dec 12, 1921, Cambridge, MA), who discovered the relationship between the luminosity and the period of Cepheid variables - pulsating stars that vary in brightness in precise periods ranging from a few days to several months.
The period–luminosity relationship, now known as "Leavitt's law," led to methods to calculate vast celestial distances.
https://en.wikipedia.org/wiki/Henrietta_Swan_Leavitt
#Leavitt
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Happy Birthday to Frank Drake (May 28, 1930 – Sept 2, 2022), astrophysicist, astrobiologist and creator of the Drake equation, which is used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way Galaxy.

The equation was formulated in 1961 as a way to stimulate discussion at the 1st scientific meeting on the search for extraterrestrial intelligence (SETI) at the National Radio Astronomy Observatory site at Green Bank, WV.

https://en.wikipedia.org/wiki/Frank_Drake
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The largest camera ever built for astrophysics arrived this week at the Rubin Observatory at Cerro Pachón in Chile.

The LSST camera, built by the SLAC National Accelerator Laboratory in Menlo Park, CA, is the final major component of the Rubin Observatory's Simonyi Survey Telescope to arrive at the summit.

Development of the observatory has been funded by the NSF and the DOE.

First light is expected in Dec 2023.

https://www.youtube.com/shorts/jB1s_YEcJi8
https://rubinobservatory.org/news/camera-arrives-chile
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The venerable Voyager 1 spacecraft is experiencing another glitch. Instead of sending science and engg. data, it is sending a 0101 bit pattern.

The problem has been narrowed down to the flight data system (FDS), which is not communicating properly with the telecom unit (TMU). A reboot did not help.

Stay tuned as NASA engrs work out a fix for this 1970's era computer, which has performed magnificently during its long 46-year journey to the planets and to outer space.
https://blogs.nasa.gov/sunspot/
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For those interested in failures and recovery in far away spacecraft, check out this thread in August, when Voyager 2 lost contact with earth due to a mispointed antenna (caused by operator error :mastodon_oops: ).
https://fosstodon.org/@AkaSci/110831401826701180
#Voyager
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NASA DSN in Goldstone, CA is currently receiving the downlink from Voyager 1 at a reduced rate of 40 bps. No uplink at this moment.

Apparently, Voyager 1 switched data rate (160 -> 40 bps) & did a full memory read-out of her Attitude and Articulation Control Subsystem, Flight Data Subsystem, and Command Computer Subsystems A&B.
Transmission time = 6 hours
Download size = ~108 kBytes

Here's hoping that the received data is not 0101... 🤞

https://eyes.nasa.gov/dsn/dsn.html
#Voyager
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In the blog post at https://blogs.nasa.gov/sunspot/, Voyager engineers point out the difficulty in diagnosing problems and crafting solutions for a spacecraft with a signal round-trip-time of almost 2 days and hardware/software developed over 46 years ago using technology long since obsolete.

"Finding solutions to challenges the probes encounter often entails consulting original, decades-old documents written by engineers who didn’t anticipate the issues that are arising today."

#Voyager
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NASA did not provide a date but it looks like this issue was discovered and acted upon on Dec 7 or 8.

The graphic below shows the schedule for Voyager 1 comms via DSN, generated on Dec 7. Normally, the downlink rate is 160 bps. On Dec 8, it was switched to 40 bps. And again on Dec 10. Some special commands for the FDS were also sent.
Since then, the D/L rate has been switched between 160 bps and 40 bps a few times with additional FDS commands uploaded.

https://voyager.jpl.nasa.gov/pdf/sfos2023pdf/23_12_07-23_12_25.sfos.pdf
#Voyager
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