end of an era: pioneer 10 fades away

[Q Classic]

PIONEER 10 SPACECRAFT SENDS LAST SIGNAL

After more than 30 years, it appears the venerable Pioneer 10 spacecraft has sent its last signal to Earth. Pioneer's last, very weak signal was received on Jan. 22, 2003.
NASA engineers report Pioneer 10's radioisotope power source has decayed, and it may not have enough power to send additional transmissions to Earth. NASA's Deep Space Network (DSN) did not detect a signal during the last contact attempt Feb. 7, 2003. The previous three contacts, including the Jan. 22 signal, were very faint with no telemetry received. The last time a Pioneer 10 contact returned telemetry data was April 27, 2002. NASA has no additional contact attempts planned for Pioneer 10.
"Pioneer 10 was a pioneer in the true sense of the word. After it passed Mars on its long journey into deep space, it was venturing into places where nothing built by humanity had ever gone before," said Dr. Colleen Hartman, director of NASA's Solar System Exploration Division, NASA Headquarters, Washington. "It ranks among the most historic as well as the most scientifically rich exploration missions ever undertaken," she said.
"Originally designed for a 21-month mission, Pioneer 10 lasted more than 30 years. It was a workhorse that far exceeded its warranty, and I guess you could say we got our money's worth," said Pioneer 10 Project Manager, Dr. Larry Lasher.
Pioneer 10 was built by TRW Inc., Redondo Beach, Calif., and was launched March 2, 1972, on a three-stage Atlas-Centaur rocket. Pioneer 10 reached a speed of 32,400 mph needed for the flight to Jupiter, making it the fastest human-made object to leave the Earth; fast enough to pass the moon in 11 hours and to cross Mars' orbit, about 50 million miles away, in just 12 weeks.
On July 15, 1972, Pioneer 10 entered the asteroid belt, a doughnut-shaped area that measures some 175 million miles wide and 50 million miles thick. The material in the belt travels at speeds up to 45,000 mph and ranges in size from dust particles to rock chunks as big as Alaska. Pioneer 10 was the first spacecraft to pass through the asteroid belt, considered a spectacular achievement, and then headed toward Jupiter. Accelerating to a speed of 82,000 mph, Pioneer 10 passed by Jupiter on December 3, 1973.
The spacecraft was the first to make direct observations and obtain close-up images of Jupiter. Pioneer also charted the gas giant's intense radiation belts, located the planet's magnetic field, and established Jupiter is predominantly a liquid planet. In 1983, Pioneer 10 became the first human-made object to pass the orbit of Pluto, the most distant planet from the Sun.
Following its encounter with Jupiter, Pioneer 10 explored the outer regions of the solar system, studying energetic particles from the Sun (solar wind), and cosmic rays entering our portion of the Milky Way. The spacecraft continued to make valuable scientific investigations in the outer regions of the solar system until its science mission ended March 31, 1997.
Since that time, Pioneer 10's weak signal has been tracked by the DSN as part of a new advanced-concept study of communication technology in support of NASA's future Interstellar Probe mission. At last contact, Pioneer 10 was 7.6 billion miles from Earth, or 82 times the nominal distance between the Sun and the Earth. At that distance, it takes more than 11 hours and 20 minutes for the radio signal, traveling at the speed of light, to reach the Earth.
"From Ames Research Center and the Pioneer Project, we send our thanks to the many people at the Deep Space Network (DSN) and the Jet Propulsion Laboratory (JPL), who made it possible to hear the spacecraft signal for this long," said Pioneer 10 Flight Director David Lozier.
Pioneer 10 explored Jupiter, traveled twice as far as the most distant planet in our solar system, and as Earth's first emissary into space, is carrying a gold plaque that describes what we look like, where we are, and the date when the mission began. Pioneer 10 will continue to coast silently as a ghost ship into interstellar space, heading generally for the red star Aldebaran, which forms the eye of the constellation Taurus (The Bull). Aldebaran is about 68 light-years away. It will take Pioneer 10 more than two million years to reach it. Its sister ship, Pioneer 11, ended its mission September 30, 1995, when the last transmission from the spacecraft was received. Information about Pioneer 10 is on the Internet at:
http://spaceprojects.arc.nasa.gov/Sp...er/PNhome.html

i'm surprised nobody mentioned this.
the article mentions that Pioneer 11 is gone as well~ does anybody know about the state of contact between the two Voyagers and DSN?

Galileo's supposed to go down soon; what of Cassini?

[Ming]

It was indeed well spent money.

However...

At last contact, Pioneer 10 was 7.6 billion miles from Earth, or 82 times the nominal distance between the Sun and the Earth. At that distance, it takes more than 11 hours and 20 minutes for the radio signal, traveling at the speed of light, to reach the Earth.

Does anybody else have a problem with this statement

[Dis]

that doesn't look right

RIP

[Q Classic]

(7.6 × 10^9 mi) / (9.3 × 10^7 mi) = 81.72

81.72 × 8 min = 653.76 min
653.76 min × (1 hr / 60 min) = 10.896 hr = 10hr 53min 46s

no, it's about right.

[Jaguar]

Originally posted by Ming
Does anybody else have a problem with this statement

Confused, first it looked wrong, now it looks ok.

[Dis]

can a radio signal travel at the speed of light? Wouldn't that be an optical signal of some sort?

[Q Classic]

a radio signal is a radio wave, radio waves are at the lowest end of the EM spectrum.

light is at the middle of it.

that's part of why radio telescopes work as well.

[Japher]

radio waves have a velocity equal to the speed of light.

[Dis]

ok I believe you

[Ming]

Originally posted by Japher
radio waves have a velocity equal to the speed of light.

Then I'm mistaken... I didn't think they did. Thanks for the info.

[Arrian]

That's too bad. I thought it was pretty cool that they could keep in contact with it even though it had gone that far out. Tough little toaster oven, huh?

Galilleo was an awesome mission too, that has gone well past the original specs.

If Cassini is 1/2 as good, it will be a success.

-Arrian

[Ramo]

Radio waves are electromagnetic waves, and all electromagnetic waves have the same speed as visible light. They have large wavelengths, meters to a couple kilometers, compared to visible light, ~3 to 7 hundred nanometers.

[Japher]

What I am wondering is:

It got to Pluto in about 11 years (1972-1983), totally possible at the speeds it was going.

Yet after that it only went another 1.8 billion miles.

Odd, that it took it 11 years to go 5.8 billion miles and the 20 years to go only 1.8 billion, for a total of 7.6 billion.

Granted that it had boosters to get it going and all, but what was slowing it down so much? The thing was averaged only 28,900 miles/hour for the length of the trip, yet it was ignited at Jupiter to speeds of 82,000 mph.

When it passed pluto in 1983 it had traveld about 5 billion miles in just 10 years! But in the next 20 years it would only travel another 2.6 billion miles? What slowed it down so much?

[Q Classic]

planet x?

i'm not quite sure what could have slowed it down. the probes did increase their velocties using the gravitational wells of the planets, but i don't recall them ever using that to slow down.

[Ben Kenobi]

What's the distance to Pluto in 1982?

Answer: The average orbital radius of Pluto is 3660 million miles; however, its orbit is more eccentric than the other planets, so much so that it is currentlyinside the orbit of Neptune (radius 2793 million miles) and will remain so until 1999.

http://newton.dep.anl.gov/askasci/ast99/ast99241.htm

Not 5.8 billion, but only 2.7 billion miles to Pluto in 1982.

That accounts for the discreprency.

[Japher]

That makes sense... I forgot to convert 5.8 billion Km to miles.

[Dauphin]

Even ignoring the NASA emulating ignoring of metric units by Japher, there is a problem with the Pioneers' velocity and distance. They don't come out right when you do the sums. The problem is significant enough to intrigue some physicists.

[Japher]

Even ignoring the NASA emulating ignoring of metric units by Japher

I is a college graduate

[CerberusIV]

Presumably it hasn't travelled in a straight line for the whole distance (as it swings past planets to use their gravity to speed up it must change course). Does this explain some of the distance/time discrepancy?

[Ben Kenobi]

Secondly, you have the distance from Pluto as well.

I've only approximated, some one would have to look to make sure.

How much are we off by BC?

[Provost Harrison]

Originally posted by Ming
Does anybody else have a problem with this statement

Nope, all looks in order to me at first inspection...

Anyway, it is the end of an era I suppose when these things start disappearing from the furthest reaches of the solar system. We just don't seem to launch things like this any more...either that or they are much lower profile now.

[Provost Harrison]

Yeah, as these probes are slingshot using planets, their path is never linear. Although that probe may be x miles as the crow flies (or as the warbird flies ), but it may have travelled much further in total...

[Dauphin]

Originally posted by obiwan18
Secondly, you have the distance from Pluto as well.

I've only approximated, some one would have to look to make sure.

How much are we off by BC?

Pioneer 10 has been off compared to NASA's calculations for over 20 years, even before it reached Pluto, and these calculations have been double checked by independent institutions. The difference is currently on the shy side of half a million kilometres - a massive discrepency. And its not a peculiar problem either. Pioneer 11, Galileo and Ulysses have demonstrated the same behaviour.

[Dauphin]

These potential sources of error have been discounted.

Errors in JPL's orbital determination software
Gravity of the Kuiper belt and gravity from the galaxy
Errors in the planetary ephemeris
Errors in the values of the Earth's orientation, precession, and nutation
Nongravitational effects from solar pressure and attitude control maneuvers
Solar wind and interplanetary medium
Nominal thermal radiation and plutonium half-life
Drifting clocks, general relativity, and the speed of gravity
Hardware problems at the tracking stations

[Unspeakable Horror]

Originally posted by Big Crunch
These potential sources of error have been discounted.

Errors in JPL's orbital determination software
Gravity of the Kuiper belt and gravity from the galaxy
Errors in the planetary ephemeris
Errors in the values of the Earth's orientation, precession, and nutation
Nongravitational effects from solar pressure and attitude control maneuvers
Solar wind and interplanetary medium
Nominal thermal radiation and plutonium half-life
Drifting clocks, general relativity, and the speed of gravity
Hardware problems at the tracking stations

And what is the current theory?

Nice finding by the way

[Dauphin]

Originally posted by Carlos113


And what is the current theory?

Gravitational effects are the most likely cause. But there aren't any theories that don't involve new physics. i.e All theories disagree with Einstein and Newton in some way.

[Joseph]

Originally posted by Q Cubed
planet x?

There is a rock out there, that I saw on the Tech channel that some are saying it could be Planet X. If I remember correctly it is about one haft of Pluto. Its a long ways from Pluto also.

[Lancer]

Ha! I outlived it.

[Tattila the Hun]

Hardly. When you're but few specs of dust, it still keeps going, somewhere...

[The Mad Monk]

Are the Voyagers also showing this behavior?