Voyager 2 Has Another Instrument Turned Off

Space.com reports that NASA engineers have turned off one of the few remaining scientific instruments that was running on Voyager 2, as the power available on the space probe continues to fall with age.  

Voyager 2 launched back in August of 1977 on a trip to Jupiter and a "Grand Tour" of the outer solar system. That mission was completed decades ago, and the probe left the solar system on Nov. 5, 2018.  Yeah, you can say the two Voyagers are in the 47th year of a 4 year mission. 

...It is currently 12.8 billion miles (20.5 billion kilometers) from Earth and is using four science instruments to study space beyond the heliosphere, the sun's bubble of influence around the solar system. NASA thinks that Voyager 2 has enough power to keep running one science instrument into the 2030s, but doing that requires selecting which of its other instruments need to be turned off. 

Mission specialists have tried to delay the instrument shutdown until now because Voyager 2 and Voyager 1 are the only two active probes humanity has in interstellar space, making any data they gather unique. Thus far, six of the spacecraft's initial 10 instruments have been deactivated. Now, losing the seventh has become unavoidable, and the spacecraft's plasma science instrument drew the short straw. On Sept. 26, engineers gave the command to turn off the instrument.

The plasma science instrument is an interesting concept.  It consists of four "cups" - detectors - to sense the amount of plasma flowing around the spacecraft.  Three of those are pointed toward the sun to measure the charged particles in the solar wind while the fourth is pointed forward, to look for charged particles coming from interstellar space.  To be honest, the instrument really hasn't done much since the probe left the heliosphere and entered interstellar space. Ironically, though, it was that instrument that verified it had left the heliosphere.  

This NASA graphic shows the locations of NASA's Voyager spacecraft in interstellar space. NASA announced the arrival of Voyager 2 in interstellar space on Dec. 10, 2018. Voyager 1 reached the milestone in 2012. (Image credit: NASA/JPL-Caltech)

The situation was that the three detectors pointed back where it came from didn't detect anything because there's no solar wind after it crossed the heliopause, and the other detector only provided useful data once every three months when the spacecraft made a 360-degree turn on its axis. It was a very practical choice of an instrument to shut down.

Both Voyagers are in the same condition, losing about 4 Watts every year.  In the 1980s, after their primary mission to the outer planets was complete, several instruments were shut down; things that were never expected to be used again. Voyager 1's plasma experiment equivalent to this one failed back in 2007 and has been off since then.   

It's a common thing among human beings to look for "big round numbers" and the race that both of the Voyagers are in is to see if they make their 50th anniversaries in space. They've both recently crossed into their 47th year, having launched in August and September of 1977.  

Reality, though, is that the Voyagers don't have much time left.  Both probes are powered by Radioisotope Thermal Generators (RTGs) and those are expected to keep the few instruments that need to run alive until 2025, but that could change with the random failure of any one of thousands of components.  The RTGs might operate longer than 2025 although probably not much longer.  Either way, eventually the RTGs will no long be able to power enough of the instruments to get data and transmit it back.  Eventually, first one Voyager then the sister spacecraft will go silent.  Even though they won't generate enough heat to power the instruments, the RTGs might keep the Voyagers a little warmer, but eventually they'll cool to almost absolute zero.  

As I said over a decade ago, if we're lucky some day a ship from Earth may find one and bring her back to whatever serves as the equivalent of the Smithsonian in those days.  In all probability, they will simply follow the Newtonian laws of motion, cool to a couple of degrees Kelvin and glide away forever, all alone in the night.

About that Spruce Pine (NC) Quartz Mine Story

One of the stories that immediately caught my attention as soon as the reports from the Hurricane Helene disaster started coming in was the one about how a small quartz provider in Spruce Pine being shut down had the potential to shut down all semiconductor manufacturing and seriously impact the modern world.  

Let me repost the first story I ever saw on this, from Virtual Mirage on October 1st one of my daily (or more) reads:

In March, a Wharton professor who studies artificial intelligence and start-ups claimed on X, “The modern economy rests on a single road in Spruce Pine, North Carolina. The road runs to the two mines that are the sole supplier of the quartz required to make the crucibles needed to refine silicon wafers.” Ethan Mollick noted at the time, “There are no alternative sources known” if supply disruptions were seen in Spruce Pines. It looks like rail and road in the area are gone, along with a chunk of Spruce Pines. [NOTE: that statement that there are no alternative sources known is contradicted by another reference I've found that says there are two large sources in India and Brazil. - SiG]

This was forwarded to Larry at VM by a friend and he noted some immediate questions about it in the comments, in particular that quartz is a "simple compound, SiO₂ with a (relatively) low melting point so that it can be made in an autoclave or similar industrial oven. Silica is the second most common mineral on the planet, so there is no shortage. I think that the industrial application finds it less expensive to mine." All of that is exactly correct. Further, every part of "modern electronics" you have, be it computer, tablet, iPad, Kindle, your phone, everything, already relies on a quartz crystal.  

As a radio designer, I couldn't tell you the number of quartz crystals, as just components I've built into oscillators (sources of radio frequency on specific frequencies) or purchased as already-built components. This goes back to the early 1980s. While in the never-ending search for ways to take costs out of computers and other consumer items, there has been a move toward less accurate ways to create a master clock for everything in the computer (or whatever), crystals still have their place where frequency accuracy is important.  It's not unusual to buy a crystal specified as some frequency even in the "several hundred" MHz range and specified to within a small number of Hertz. An off the shelf clock oscillator may be specified to within 25 parts per million (25 ppm), a temperature compensated crystal oscillator (TCXO) may be specified to 1/2 ppm or less. (For example, a 10.000000 MHz crystal to 1/2 ppm will be within + 5 Hz of that at all times.) The most tightly controlled oscillators are Oven Controlled Crystal Oscillators (OCXO) and they are more stringently specified. (TCXOs run at the ambient temperature but have their frequency drift controlled with some clever circuit design; OCXOs run at a high (higher than the ambient temp rating) temperature and reduce variation by locking the temperature, and using quartz cuts optimized for that temperature - as well as some clever circuit design).  

I can't give a precise date but I don't believe a quartz crystal resonator or oscillator has been made with slices of quartz crystals out of the ground since the 1970s.

The article that many have referred to appears be this one on Wired by Vince Beiser. There's a vast misunderstanding or failure to communicate. This is what the source article is referring to as coming from Spruce Pine's deposit of high purity quartz (HPQ):

Rocks like these high-grade silica samples mined near Charlotte, North Carolina, are the basis for the quartz crucibles being discussed.  Image credit: Charles O'Rear/Getty Images

This lab-grown quartz crystal is what the crystals used in oscillators, crystal filters and other circuits are cut from. Millions of these have been made to cut crystal blanks from. This is a sample of an early effort to grow crystals at Bell Labs in 1956. Image credit Weinrich Minerals.  The rusted steel on both ends (more visible on the right) held a "seed" crystal for the new crystals to grow on.

Yes, the wired article referred to quartz crucibles used for purifying Silicon, not creating oscillators and other resonators. The crucibles look more like the rocks in the first picture - not a crystal structure like that. I interpret that to mean the crucibles are made from polycrystalline quartz and not a single big crystal like the one above. 

Notice the white rim (most prominent at the bottom front and top back) surrounding the silvery chunks of silicon? That's the crucible.  

The point is that the crystals grown for those other uses have been purified. Everything that reduced the purity of the crystals they started with has been removed.  If it can be done for that use, it can be done for crucibles or any other use. 

What's going on here is strictly economic. The silicon wafer makers would rather take the high purity quartz (HPQ) or ultra-pure quartz mined in Spruce Pine (or a few other places in the world) to make the crucibles from than purify lower grade quartz. How big those cost trades are, including going to "slightly lower quality quartz" or importing from the other couple of places on earth, is never talked about.

The Sad Truth is We're Stuck With SLS

I assume you're probably familiar with this old saying, BOHICA. If not, it's an acronym for Bend Over, Here It Comes Again. You're about to get something shoved up your ass. 

In this case, it's the Space Launch System, or SLS, the extremely overpriced rocket system that is the launch vehicle for NASA's Artemis program to return to the moon. I've basically been a one note song on getting rid of SLS since I first started studying it. A recent example here has leapt up my list of most read posts in the last year.

They're talking about launches that cost $4.1 billion each, and a system that couldn't launch more than (maybe) twice a year even if we could afford it. It turns out that practically every date associated with Artemis and returning to the moon slides farther into the future every time they update the schedules, and in step with that, every cost estimate goes up every time the question gets asked.  

Why talk about this again? Where is this going? Eric Berger, the senior space correspondent at Ars Technica has put up a post today about rescuing the Artemis program, "The politically incorrect guide to saving NASA’s floundering Artemis Program." In it, he modifies SLS somewhat, but mostly attacks the needless complication of the moon landing program. In doing so, he concedes we're stuck with the SLS.  His main target is getting rid of the needless complication of the Lunar Gateway (some background info) but his overall plan is:

• Cancel the Lunar Gateway
• Cancel the Block 1B upgrade of the SLS rocket
• Designate Centaur V as the new upper stage for the SLS rocket.

The Block 1B SLS is the largest version, which is dependent on getting the Exploration Upper Stage running.  My first link (2nd paragraph) concentrates on what a hideous mess the EUS has been and continues to be.  Eric envisions using the Centaur upper stage in place of the EUS. 

Essentially, Block 1B of the rocket exists solely to build out the Gateway. There is no need for this new SLS stage for human landing missions. Nor is it needed to deliver material to the Moon. NASA’s two largest lunar landers under contract, SpaceX’s Starship and Blue Origin's Blue Moon, plan to use their own large rockets. Far from needing the expendable SLS rocket, NASA will have two reusable means to deliver large cargo to the Moon.

By canceling Block 1B, NASA would not only save billions of dollars in yet-to-be-expended development costs but also significantly reduce the per-launch cost of the SLS rocket. That’s because the cost of a single Exploration Upper Stage is likely to be around $1 billion, which is ludicrous for just a rocket’s second stage.

Time for some tough truths. We're currently in 1960s-style "moon race" and we're headed for a loss. Everything has been sliding farther out; nothing is ahead of schedule.

• The first crewed flight on the Orion spacecraft, a vehicle that has been in development for two decades, remains in doubt due to concerns with the heat shield.
  
• The first lunar landing mission has no reliable date. Officially, NASA plans to send this Artemis III mission to the Moon in September 2026. Unofficially? Get real. Not only must Orion’s heat shield issue be resolved, but it's unlikely that both a lunar lander (SpaceX’s Starship vehicle) and spacesuits (built by Axiom Space) will be ready by this time. The year 2028 is probably a realistic no-earlier-than date.
• The space agency’s plans after Artemis III are even more complex. The Artemis IV mission will nominally involve the debut of a larger version of NASA’s Space Launch System (SLS) rocket, a new launch tower, and a stopover at a new space station near the Moon, the Lunar Gateway.
• There is increasing evidence that China is pouring resources into a credible lunar program to land two astronauts on the Moon by 2030, seeking a geopolitical “win” by beating America in its return to the Moon.

The way to get back to the moon isn't with the sort of needless complication shown in this GAO illustration. It's more like we did it in the 1960s: concentrate on getting there and landing, not all this other stuff.

The big problem here is that there are no immediately ready replacements for SLS, the Orion capsule or Starship HLS (Human Landing System). There's no existing way to put an Orion capsule on anything besides the SLS. Could SpaceX design an improved Crew Dragon with a heat shield designed for the higher temperatures of lunar re-entry? Has anyone asked?

Closing words to Eric (and go RTWT) 

Proponents of the Lunar Gateway argue that it adds sustainability to the Artemis Program by providing a way station. The problem is that this way station, in an orbit far from the lunar surface, really isn’t on the way to anywhere.

To get somewhere, Artemis must avoid going nowhere.