Voyager-1 at 100 AU!, A space milestone this month Options

[ilbasso]

Celebrate when it gets 100AU from the point where Earth was when Voyager was launched.

We're well past that if you take into account the Earth's and the Sun's motion due to galactic rotation...
...and motion of the Milky Way relative to the rest of the Universe...

[Planet X]

By the way, August 25th is prety close to celebrate the 17th anniversary of Voyager II fly-by of Neptune.

Well, it should be known that August 26th marks the 25th anniversary of Voyager 2's Saturn encounter. What a perfect day for Voyager 1 to reach 100 AU from earth! I'm already celebrating Voyager stuff that day, so why not have one thing more to celebrate. Later!

J P

[dilo]

We're well past that if you take into account the Earth's and the Sun's motion due to galactic rotation...
...and motion of the Milky Way relative to the rest of the Universe...

Not speaking of universe expantion, Mr strangelove!

[ljk4-1]

I would rather prefer AU as the reference from Sun. The Earth is no longer as the center of the world which were tought in the older times....

Rodolfo

That is a relatively modern perception of how the ancients viewed the world.

If you read Dennis R. Danielson's The Book of the Cosmos: Imagining the Universe
from Heraclitus to Hawking, you will find that the ancients viewed Earth as being not
at the center of all things in terms of either physical parameters or importance, but
at the bottom of a vast pit both in the literal and moral sense. Only as one rose
above the "sphere" of the Moon did one find a more pure and perfect existence,
as the stars and planets were thought to exist in.

It took Copernicus and especially Galileo to rise us up from the mire and make us
one among the stars. This idea that Earth was "just" a planet circling a star was
thrilling to Galileo in that sense, and deeply concerned the powers that be (read
The Catholic Church), for if mere mortal, sinful humans were not wallowing down
in the cosmic cess pool of existence in constant need of saving, then their self-
made authority on Earth was threatened - that's what was really going on between
Galileo and the Church.

As for Voyager and the 100 AU mark, the amazing thing is that sooner than later, for
all of our interstellar probes, the distance differences between Sol and Earth will be
virtually irrelevant.

[Guest_Analyst_*]

The two Voyager spacecraft have always been special for me. From a scientific, a programmatic and an engineering point of view they stand out.

They explored four planets in detail for the first time (I am a little unfair to Pioneer 10 and 11), and countless moons. They discovered new moons, volcanos on Io and geysers on Triton. The Voyagers carry an almost complete suite of then state of the art instruments found rarely before and after. Today budget pressure leaves you often with only a very limited number of instruments. Look at DAWN, we built the first asteroid orbiter and cut the magnetometer and laser altermeter. Or MER without a weather station.

It has not been easy for the Voyager program in the 1970ies. There were first four much larger probes. Later it was hoped to sent one to Pluto. Not to happen, only two smaller ones, less expensive. Then politics wanted to shut them down after the Saturn encounter. Now this program has been running for 35+ years. A lot of their fathers retired or passed away, they are still working at the final frontier.

Their engineering design included some very clever things, some used for the first time. I am still impressed by the telecom system: X-band primary with 115.2 kbps from Jupiter, 21.6 kbps from Neptune. New Horizons will have 768 bps planned from Pluto, hopefully a little more (maybe twice). Onboard image compression. Important for rapid instrument pointing is the scan platform. Or look at the scheduling difficulties Cassini has between data collection and downlink becuase there is no such platform. Also for the first time: an integrated SRM and hydrazine trusters. And gyros and star trackers still working after 29 years. So they still point to earth and hopefully will for a long time to report entering true interstellar space.

I wish them a long live, always a good link margin. And may the budget last longer than the RTGs.

Analyst

[dilo]

Well said, analist!
Voyager mission is a miracle, from both science and tech standpoint. I deeply admire who conceived, build and managed these probes.
Can you tell more about initial plan to send 4 larger spacecrafts???

[JRehling]

Thirded, there comes a point where the meaningful measurement uses the system star as the reference point.

I don't know -- speed of light travel time is still based on Earth, until DSN expands to the Sun.

I bet a lot more people have looked into the sky, picked out a small light and wondered "How far away is that?" than have wondered "How far is that from the Sun?"

Earth-Firsters!

[Guest_Analyst_*]

Voyager, the grand tour, started as the Thermoelectric Outer Planet Spacecraft (TOPS) in the late 1960ies Because of the long travel time a new computer, the so called Self Test And Repair (STAR) general purpose machine was planned to be used. Different launch strategies were discussed. One was two launches in 1977 to Jupiter-Saturn-Pluto and two in 1979 to Jupiter-Uranus-Neptune. The ideal planetary alingment in the late 1970ies has been identified at Caltech/JPL. The spacecraft were not that much larger (although they required a Titan 3E with 7 segment SRMs for some trajectories), but more sophisticated, designed to suvive 10+ years, and thus more expensive. In the early 1970ies, during the end of Apollo and the birth of the Space Shuttle, the Nixon administration canceled TOPS, the grand tour, for budget reasons (They had a useless war to fight, very much like today.).

Shortly thereafter NASA came up with Mariner Jupiter-Saturn (MJS), a design based on the Mariner spacecraft, being less expensive and more simple. MJS used a lot of the Viking computer and you can see the Mariner heritage if you look at the 10-sided bus. During development MJS involved into an almost new design: 3.7m high gain antenna, X-band primary, radiation hardened parts, RTGs, hydrazine trusters etc. But MJS was planned only explore Jupiter and Saturn within a four year mission. Before launch it was renamed Voyager (The program to develop unmanned Mars landers to be launched on Saturn launch vehicles has also been called Voyager in the 1960ies and later became Viking.). During launch were was the option to send the first launched spacecraft (JSX) to Uranus (X=U), if the other (JST) performed well during its mission including the very important close Titan encounter. We all know it did and Voyager 2 went to Uranus and Neptune. And both are still working.

It is a great story, even long before launch. A good reference is: Dethloff/Schorn: To The Outer Planets And Beyond - Voyager’s Grand Tour

Analyst

[edstrick]

The AIAA journal "Astronautics and Aeronautics" had a major article on TOPS in an issue in the early 70's, before the mission was canceled and re-created as Mariner Jupiter/Saturn, then Voyager. I was P****D when they renamed the vehicles from Mariner 11 and 12 to Voyager 1 and 2. I'm sure it was a NASA HQ public information office stupidity, figuring a #1 would be more interesting than a #11.

[dilo]

Thank you for the infos, Analyst!

[ljk4-1]

The AIAA journal "Astronautics and Aeronautics" had a major article on TOPS in an issue in the early 70's, before the mission was canceled and re-created as Mariner Jupiter/Saturn, then Voyager. I was P****D when they renamed the vehicles from Mariner 11 and 12 to Voyager 1 and 2. I'm sure it was a NASA HQ public information office stupidity, figuring a #1 would be more interesting than a #11.

But then we wouldn't have had Star Trek: Voyager, and what would V'Ger have done?!

M'rner?

[paxdan]

But then we wouldn't have had Star Trek: Voyager, and what would V'Ger have done?!

M'rner?

p'neer

*snigger*

[mchan]

No, the Klingons blew P'neer to bits in one of the movies.

[ljk4-1]

No, the Klingons blew P'neer to bits in one of the movies.

Star Trek 5: The Final Frontier, made in 1989. The worst of the lot, made
worse by having the Klingons use humanity's first ambassador into the galaxy
as target practice.

They did recreate Pioneer 10 accurately, except that the famous Plaque was
bolted on facing in towards the probe to protect its engravings from the
ravages of deep space. But obviously it was not enough to protect it
from Klingon phasers.

I also don't think Pioneer 10 would look quite as worn as the film version
did in just 300 or so years, but I haven't had the chance to check the probe
in person.

http://www.memory-alpha.org/en/wiki/Pioneer_10

I suppose this also means that since Pioneer 10 couldn't have gotten too far
from Earth on a relative scale in just three centuries, the Klingon warship was
pretty darn close to the Sol system. Voyager 6 (V'Ger - not M'Rner) at least
had the excuse of falling into a black hole to get so far away so fast.

[Holder of the Tw...]

without a doubt, celebrate 100 AU from the sun

Can't help but doubt it. 100 AU from the "creator", say I. V'ger could care less about transmitting to the sun. It's locked on to receivers that will be 100 AU away later this month.