The engineers who designed the #Voyager probes half a century ago even thought of the possibility that a wrong sequence of commands may point the antenna dish away from earth (like someone did a couple of days ago).
And they implemented a self-adjusting mechanism that a few times a year scans the positions of a few known stars to infer the position of the earth, and point back the antenna in the right direction.
50 years later, these wonderful machines are still working, tens of billions of km away from earth, with only 69 KB of RAM, and even a wrong sequence of commands won't put them out of use, while nowadays 4 GB of RAM aren't even enough to start VsCode or IntelliJ.
The more I understand how they were designed, the more I feel like an early Medieval engineer looking at the Pantheon or other marvels or Roman architecture. Some amazing skills, knowledge and attention to details have been lost from that generation to ours.
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/
1/n
The two Voyager spacecraft, launched on Sept 5, 1977 and Aug 20, 1977, have been traveling in space for over 46 years.
Voyager 1 is farther away from earth at 24.3 bil km (22.5 light hours), while V2 is 20.3 bil km away, located below the ecliptic. Both spacecraft are in interstellar space.
Here are the locations and some vital stats on the two Voyager spacecraft.
Richard Stephenson of DSN Canberra explains on twitter how NASA verified that the uplink is working.
They sent a command to Voyager 1 to switch between non-coherent mode and coherent mode transmission.
In coherent mode, the Transmission clock is derived from the Rx signal instead of from the AUX oscillator. This changes the Tx RF frequency a bit which was detected at the DSN.
Confirmation today from the Voyager 1 team that the transmission received on Sunday contained science data from 2 of the 4 operating instruments - the plasma wave subsystem and the magnetometer. The other 2 instruments - the cosmic ray subsystem and the low energy charged particle instrument - require recalibration, which will be done in the coming weeks.
The delicate software operation is working as expected.
Voyager's computer systems were custom-built using 1960s technology, with clock speeds measured in KHz and RAM in kbytes, running hand-crafted software, crammed into 4K of 18-bit wide plated-wire memory (similar to but better than core mem).
And yes, it uses digital 8-track tape for storage.
The custom-designed hardware, (upgraded) software and instruments are mostly still functioning after 46 years in space!
tout est absolument dément sur ces missions... La #nasa patche les sondes #Voyager 46 ans après leurs lancements.
Le patch va mettre plus de 18h (à la vitesse de la lumière) à leur parvenir tellement elles sont loin. On transmets à 16bps, avec une antenne de 70m et une puissance de 96KW. Dans l'autre sens, capter Voyager c'est comme déchiffrer un signal émis avec un briquet à 15000km...
My utmost respect to the NASA/JPL engineers who have to debug Voyager 1's cryptic FDS issue with a 45 hour interval between sending the command and receiving a reply, using paper documentation, methodologies, and flight software and hardware that are all more than 40 years old and whose developers are mostly dead. Oh, and with no ground simulator. Incomprehensible.
I must admit, this news about #Uranus and #Neptune has me shook:
"A fresh analysis of Voyager 2's images show both ice giants are in fact a similar shade of greenish blue, which is the 'most accurate representation yet' of the planets' colors, the new study finds."
New image of Uranus taken by the JWST shows its north polar cap, its exquisite rings and 14 of its moons.
The image was taken by the NIRCam camera on Sep 4, 2023 at IR wavelengths 1.4, 2.1, 3.0 and 4.6 µm. This 566x409 image is part of a larger field-of-view image.
Uranus' axis is tilted by 98°. With an orbital period of 84 years, each pole faces the Sun (and Earth) for 42 years! During the years around the solstices, we can see its rings almost face on.
Images of Uranus taken by the venerable Voyager 2 spacecraft on Jan 24/25 1986.
The fully lit image was taken on Jan 24, 1986 during approach. The pale blue-green color results from red-light-absorbing methane in Uranus' atmosphere.
The crescent image was taken from 1 million km beyond Uranus, as Voyager 2 raced away from the planet on its way to Neptune and beyond.
The image of the back-lit rings was taken about 3.5 hours after closest approach.
To celebrate the recovery of communications with #Voyager2, here is a bunch of classic Science Magazine, Nature, and Nature Astronomy covers featuring the adventures of the epic spacecraft, now located 19.9 billion kilometers away from Earth 🌍 📡 🚀
We are celebrating Christmas at partner's parents with the same raclette grill as 20 years ago - which is pretty impressive, but not quiet as much as the Voyager spacecrafts 😅 Voyager 2 was launched on August 20, 1977 - still working, still teaching us new things about the most external parts of the solar system.
With many thanks to @schnedan for the idea to draw Voyager :)
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?
Here is Carl Sagan unveiling the Pale Blue Dot image on June 6, 1990 and eloquently describing what that image meant for humanity.
"Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves."
「 Voyager was the first unmanned mission to include distributed computing, partly because the sheer number of tasks to be executed with precision during the high-stakes planetary fly-bys would exceed the capabilities of any single computer that could be made flyable. There was a social engineering angle to this as well, in that it kept the various engineering teams from competing for resources from a single computer 」