Aug 252017
 

Today is a big day for the two Voyager spacecraft, designed to explore objects in the solar system and then go beyond into interstellar space. Sounds a little like Star Trek, doesn’t it? On this date in 1981, Voyager 2 made its closest approach to Saturn and in 1989 made its closest approach to Neptune, the last planet in the Solar System (although at the time Pluto was considered the last). On this date in 2012, Voyager 1 entered interstellar space, becoming the first human-made object to do so. I’m impressed by the voyager journeys for a couple of reasons. First, I am impressed that NASA could have the basic wisdom, foresight, and confidence to launch a couple of craft into the Solar System knowing that it would take decades for them to get to the edge (and they could break down anywhere along the way). Second, I am impressed by the sheer quantity of close photographs and other data returned over the years, never mind the glorious quality of some of the images. I feel a gallery coming on.


Voyager 2 was launched by NASA on August 20, 1977, to study the outer planets. It was launched 16 days before its twin, Voyager 1, on a trajectory that took longer to reach Jupiter and Saturn but enabled further encounters with Uranus and Neptune. It is the only spacecraft to have visited either of the ice giants. Its primary mission ended with the exploration of the Neptunian system on October 2, 1989, after having visited the Uranian system in 1986, the Saturnian system in 1981, and the Jovian system in 1979. Voyager 2 is now in its extended mission to study the outer reaches of the Solar System and has been operating for 40 years and 5 days as of August 25, 2017. It remains in contact through the Deep Space Network. Sometimes I wonder how this is possible. Think about the technology on board for starters. My current cell phone has 100 times more computing power than the computers on the Voyagers. If you are old enough, think back to what computers were like in 1977 when they were launched. Fortunately computers on earth can do all of the heavy lifting nowadays. The Voyagers just have to just keep plodding along. And they are – amazingly. Computers back home can enhance the images and data as it comes back.


Voyager 1 was launched by NASA on September 5, 1977. Having operated for 39 years, 11 months and 20 days as of August 25, 2017, the spacecraft still communicates with the Deep Space Network to receive routine commands and return data. At a distance of 139 AU (2.08×1010 km) from the Sun as of July 1, 2017, it was the farthest spacecraft from Earth as well as the farthest human-made object. It is also the most distant object in the solar system whose location is known, even farther than Eris (96 AU) and V774104 (~103 AU).


The probe’s objectives included flybys of Jupiter, Saturn and Saturn’s large moon, Titan. While the spacecraft’s course could have been altered to include a Pluto encounter by forgoing the Titan flyby, exploration of Titan, which was known to have a substantial atmosphere, took priority. It studied the weather, magnetic fields and rings of the two planets and was the first probe to provide detailed images of their moons. After completing its primary mission with the flyby of Saturn on November 20, 1980, Voyager 1 began an extended mission to explore the regions and boundaries of the outer heliosphere. On August 25, 2012, Voyager 1 crossed the heliopause to become the first spacecraft to enter interstellar space and study the interstellar medium. Voyager 1’s extended mission is expected to continue until around 2025, when its radioisotope thermoelectric generators will no longer supply enough electric power to operate its scientific instruments. I’d say that’s a fair bang for the trivial bucks.

At a distance of 115 AU (1.72×1010 km) from the Sun as of July 30, 2017, Voyager 2 is one of the most distant human-made objects, along with Voyager 1, New Horizons, Pioneer 10 and Pioneer 11. The probe was moving at a velocity of 15.4 km/s (55,000 km/h) relative to the Sun as of December 2014 and is traveling through the heliosheath. Upon reaching interstellar space, Voyager 2 is expected to provide the first direct measurements of the density and temperature of the interstellar plasma.

Here’s your gallery:

 

There’s tons more if you look.


Cooking with a microwave seems suitable for this anniversary. By uninformed estimate I expect that 99% of microwave oven usage is heating stuff up. I’m told, on reliable authority this time, that the majority of younger, first-time home buyers in the US want to be sure that the house they buy has a microwave, and don’t care about stoves, conventional ovens, and such. Clearly I belong to an older generation. I’ve had microwave ovens over the years and have mostly used them for reheating leftovers and quick thawing of items. They do that job very well and I’m glad of it. But they can do so much more. Here’s 2 videos. You can find hundreds more:

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