As always, small stories I found interesting.
Japan's SLIM Lunar Lander Wakes Up Again
For the second time, Japan's first lunar lander SLIM (Smart Lander for Investigating Moon) has awakened from the cold lunar night and "phoned home."
Mission team members announced the news via X on Wednesday (March 27), in a post that also featured a photo newly snapped by the lander's navigation camera.
Yes, that's the first photo after SLIM contacted ground controllers and was shot when they established contact, not weeks ago. While I'm not sure of this I think the time tag of 11:28 PM on March 27 is the time in Japan of the Tweet, since that's the time tag I got at X, and it's the same one as shown at the Space.com original story (link above). I don't think we're in the same time zone but Space.com has a similar screen capture from X and they posted hours before I did.
JAXA scientists added that most of the functions that survived the first lunar
night survived this one as well.
Today's Delta IV Heavy launch was scrubbed, rescheduled for Friday
ULA scrubbed today's launch attempt after a couple of delays moved the 1:40 PM EDT liftoff until well after 2:00 PM. The final scrub occurred just after t-4:00 minutes "... due to an issue with a liquid pump failure on the gaseous nitrogen pipeline which provides pneumatic pressure to the launch vehicle systems..."
The current liftoff time is set for 1:37 PM Friday, March 28. The chance of acceptable weather goes up from today's 30% to 60%.
JPL Team optimistic they can get Voyager 1 working again
Speaking at a March 20 meeting of the National Academies’ Committee on Solar and Space Physics, Joseph Westlake, director of NASA’s heliophysics division, said it appeared possible to fix the computer problem on the nearly 50-year-old spacecraft that has disrupted operations since last November.
Westlake went on to say:
“It’s a part failure on one of the memories and they’re looking for a way to move a couple hundred words of software from one region to another in the flight computer.”
In the 8 bit computer that was built from discrete circuits that Voyager 1 is running, a word is 2 bytes or 16 bits. While the Intel 8008, the first single-chip 8-bit microprocessor was available at the time Voyager was being built and readied for launch, I'm going to assume that it wouldn't have met the environmental requirements for launch into deep space. That, or the designers weren't convinced the 8008 was as good as "the way we've always built processors." Out of Earth's magnetic shield, Voyager's components are subjected to around the clock bombardment with all sorts of radiation out there. This is one of the places where higher levels of integration and smaller transistor sizes have drawbacks. In this case, the drawback is making modern parts more susceptible to having a logic state changed by things like a single neutron going through the chip.
The 1802 and the 6502 microprocessors were built in a "rad-hard" configuration for space probes. Slow clock speeds due to IC geometry, extra doping for radiation hardening. Not "smart" by today's standards, but durable as hell, I can't remember which one was used for the two Voyagers.
ReplyDeleteI'm familiar with all of the processors from the 70's. Even the 4004...
My wife and I joked last night, in my best Grandpa Simpson voice, "I remember the 4004. It was groundbreaking! These kids with their 8 bit processors don't know how good they've got it!"
DeleteI think the first microprocessor chip I actually worked on was the 8085. Hardware only, not programming. But I did work on a PDP-11 entering the paper tape reading software with toggle switches on the front panel.
SiG, that was the bootstrap program (43 words for the IBM) to read the cold boot loader from either Hollerith cards (IBM) or from the PTP (Paper tape) reader.
DeleteOne of the evil jokes we used to do is squirt mineral oil on the paper tape rolls which caused the (optically-read) reader to misread. Badly. You would have to recalibrate the reader to get it to read and/or copy it to a fresh tape if you had access to a duplicator and it still read the tape using the wires instead of optically. Like I said, evil...
You missed all the fun with the 1802, 6502, 8008, and the single-chip microcontrollers like the 8040 (8035) and 8051...
I go waaaaaay back.............. to 1967.
Thank you for the update.
ReplyDeleteI cut my teeth on the RCA COSMAC 1802 processor - 16 general purpose registers, 16 bits each, orthogonal heaven. And radiation hardened, pretty much bullet proof. Those were the days ....
ReplyDelete