For those curious about the downlink data rates used by Voyager, it uses 40 bps for engg. data and 160 bps for science data. It requires use of the 70m antenna at the 3 DSN sites. A 1.4 kbps rate is supported with 5 arrayed antennas at Madrid.

Voyager 1 is 24 billion km away. Tx power = 23W. Rx power = -160 dBm (1e-19 watts). A WiFi signal is > 10 billion times stronger!

Earlier data rates (kbps) for V2:
From Jupiter: 115.2
Saturn: 44.8
Uranus: 29.9
Neptune: 21.6

https://descanso.jpl.nasa.gov/DPSummary/Descanso4--Voyager_new.pdf
30/n

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
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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

Birthdays are unfortunately also reminders of one's advancing age and creaky body parts 🙁

The 34-year old Hubble Space Telescope has been down since April 23 due to a malfunctioning gyroscope, needed for accurate pointing.

The same gyro caused Hubble to enter safe mode last November.

Only 3 out of 6 gyros have been working since 2018. Hubble can operate with just one gyro at somewhat reduced functionality, but NASA is attempting to revive the faulty unit first.

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

To celebrate its 34th anniversary, the Hubble Space Telescope snapped this image of the Little Dumbbell Nebula (aka Messier 76 or M76), located 3,400 light-years away in the constellation Perseus.

M76 has a two-lobed structure of colorful, mottled, glowing gases expanding into space. Blistering UV radiation from a super-hot dying star (the white dot in the center) is causing the gases to glow. The red color is from nitrogen, and blue is from oxygen.

NASA, ESA, STScI
https://science.nasa.gov/missions/hubble/hubble-celebrates-34th-anniversary-with-little-dumbbell-nebula
2/n

A star will be born in the coming months! Not quite, but a star in the T Coronae Borealis binary system (T CrB) will explode as a nova between Feb and Sept and become visible to the naked eye.

How do astronomers know? It is because this is a “recurrent nova”, one that grows and erupts every ~80 years. It is known to have erupted in 1217, 1787, 1866 and 1946.

After explosion, it will be visible to the unaided eye for several days and about a week with binoculars.

https://blogs.nasa.gov/Watch_the_Skies/2024/02/27/view-nova-explosion-new-star-in-northern-crown/
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34 years ago, on Feb 14, 1990, Voyager 1 took this image of the "Pale Blue Dot" from 6 billion km away, minutes before its cameras were shut off forever.

Carl Sagan, who played a key role in the mission wrote -
"To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.”

34 years later, how well are we doing on these 2 counts? How can we do better?

https://www.jpl.nasa.gov/images/pia23645-pale-blue-dot-revisited
1/n

Not a good day for space missions 😞

During a short up and down Flight 72, Mars helicopter Ingenuity lost its comm link with rover Perseverance. NASA engineers are working on restoring it.

This follows Flight 71 on Jan 6 which made an emergency landing 35 seconds into a 125 sec flight; apparently the relatively featureless sandy terrain proved difficult for its navigation system.

Meanwhile, Voyager 1 is still sending garbled data.

Stay tuned.

https://mars.nasa.gov/technology/helicopter/status/508/flight-72-status-update/
1/n

Ingenuity and Perseverance turn on their comm systems and talk during certain pre-determined periods of the day (e.g., at the top of the hour), to conserve power. Ingenuity initiates the call.

For this to work, both systems need to have "wall-clocks" (i.e., the date/time counter) whose values match closely.

Since Ingenuity's clock got reset and restarted due to the low power condition, the times when Ingenuity and Perseverance attempted to communicate with each other no longer matched.

5/n

This incident sounds very similar to a comm. outage that occurred in May 2022.

Then, increased atmospheric dust caused a reduction in solar panel output. One night, battery capacity fell low enough that a controller chip was automatically powered off as a safety measure.

Consequently, Ingenuity's time-of-day clock get reset.

That led to a failure to communicate with Perseverance, when power levels came back to normal.

Why?

https://mars.nasa.gov/technology/helicopter/status/379/nasas-ingenuity-in-contact-with-perseverance-rover-after-communications-dropout/
4/n

Good news from JPL - the Mars helicopter team managed to reestablish contact with Ingenuity after its comm loss since the middle of Flight 72. The team is reviewing data to better understand the root cause of the comm outage.

This was accomplished by "instructing Mars rover Perseverance to perform long-duration listening sessions for Ingenuity’s signal."

Let's take a look at what that means.

#Mars #Ingenuity
3/n

Mars Helicopter Ingenuity was just a 30-day technology demonstration mission to test powered, controlled flight on another world.

Ingenuity completed its tech demo phase after the 3rd flight on April 25, 2021. After another 2 flights, it transitioned to a new operations demonstration phase.

Almost 3 years later, Ingenuity has completed 72 flights and is still going strong in support of the overall mission.

Overachiever much?
👏

https://mars.nasa.gov/technology/helicopter/#Flight-Log
#Ingenuity #Mars
8/n

FYI - the Ingenuity team did not know in May 2022 that time-sync loss was the problem and not something more catastrophic, but they had anticipated such events and had a bag of solutions to try.

Also, part of the solution to the May 2022 problem was to lower Ingenuity's thermostat at night, so that the heating system consumed less power and the electronics could stay up (in low power mode) all night. The thermostat setting was restored once solar insolation levels rose to normal levels.

7/n

The solution to this problem caused by unsynchronized clocks is obvious - configure Perseverance to keeps its comm. system continuously turned on for a few hours!

That's what they did on May 5, 2022. A few hours later, Percy received Ingenuity's call, exchanged status info. and promptly set Ingenuity's clock to the correct value.

This is what JPL must have done today - "instructing Perseverance to perform long-duration listening sessions for Ingenuity’s signal."

I doubt they use NTP 🕰️

6/n

OTD on Jan 7, 1610, Galileo Galilei, using a telescope of his own design, discovered 3 moons of Jupiter - Callisto, Europa and Io. He discovered Ganymede 6 days later.

He observed 3 "stars" around Jupiter, whose positions changed in observations on subsequent nights. On Jan 10, Galileo noted that one of them had disappeared. Within a few days, he concluded that they were "moons" orbiting Jupiter, a discovery that was anathema to the Church at that time.
1/n

It's Monday!
What's your mood today and in general on Mondays?

Pics from The 2023 Comedy Wildlife Photo winners - https://newatlas.com/photography/2023-comedy-wildlife-photo-winners/#gallery:1
Pic 1 credit: John Blumenkamp
Pic 2 credit: Jason Moore

We can get a sense of what the Euclid images tomorrow will look like by observing this test image released on July 31. This is a raw engineering image, taken by the VIS instrument, with very little processing; even the traces caused by cosmic rays are visible in this image.

Note that the original image is 24k x 24k pixels!

https://www.esa.int/Science_Exploration/Space_Science/Euclid/Euclid_test_images_tease_of_riches_to_come
#ESAEuclid #Euclid
2/n

Launched on July 1, the Euclid space telescope is operating in a Lissajous/halo orbit around the Sun-Earth L2 Lagrange point.

Other space telescopes in orbit around L2 include Gaia and JWST.

Unlike a Halo orbit, a Lissajous orbit precesses after each revolution. Both orbits are unstable and require periodic (~monthly) thruster firings for station-keeping.

https://www.researchgate.net/publication/361812339_The_Euclid_Wide_Survey
#ESAEuclid #Euclid
4/n

This is another raw test image, taken by Euclid’s Near-Infrared Spectrometer and Photometer (NISP) instrument.

NISP has an imager and a spectrometer, which allows it to accurately estimate distances to celestial objects.

https://www.esa.int/Science_Exploration/Space_Science/Euclid/Euclid_test_images_tease_of_riches_to_come
#ESAEuclid #Euclid
3/n

Will the first full-color images from the ESA Euclid space telescope today look like these images generated using simulations by scientists at the Euclid Consortium?
In another 30 minutes, we will find out!
https://www.euclid-ec.org/public/data/simulations/
#ESAEuclid #Euclid
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