Old July-2nd-2004, 01:41 AM   #1
BFrank
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Saturn

UN-REAL!
... except that it is.


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Old July-2nd-2004, 08:35 AM   #2
Slurpy
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Oh yeah, baby! I can't wait to see the pictures from Cassini. It takes radio waves 80 minutes to go from Saturn to Earth....934 million miles away! I'd like to see a program describing the scientific planning/physics behind sending a probe from HERE to THERE. Both Saturn and the Earth are moving at thousands of miles a second...rotating, in elliptical orbits that take varing times to go around the Sun.....(yes that's my high-school science level description ) But....how the hell do we do it? I heard the analogy that putting the Voyager on Mars was like hitting a hole in one from Florida to Houston. Calculations had to be that precise. So, how do we do it? I mean I can SEE Saturn once in a while but to think "I'm gonna shoot something up to it and have it orbit".....uh, yeah. I now see that there are preliminary pictures at saturn.jpl.nasa.gov Way cool.
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Old July-2nd-2004, 08:36 AM   #3
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Cassini Spacecraft Arrives at Saturn
June 30, 2004
(Source: Jet Propulsion Laboratory)

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

The international Cassini-Huygens mission has successfully entered orbit around Saturn. At 9:12 p.m. PDT on Wednesday, flight controllers received confirmation that Cassini had completed the engine burn needed to place the spacecraft into the correct orbit. This begins a four-year study of the giant planet, its majestic rings and 31 known moons.

"This is a tribute to the team at NASA and our partners at the European Space Agency and the Italian Space Agency, to accomplish this feat taking place 934 million miles [1.5 billion kilometers] away from Earth," said Dr. Ed Weiler, associate administrator for space science at NASA Headquarters, Washington, D.C. "What Cassini-Huygens will reveal during its tour of Saturn and its many moons, including Titan, will astonish scientists and the public. Everyone is invited to come along for the ride and see all this as it is happening. It truly is a voyage of discovery."

Members of the Cassini-Huygens mission at NASA's Jet Propulsion Laboratory, Pasadena, Calif., broke into cheers and high-fives as NASA's Deep Space Network confirmed receipt of the signal indicating successful entry into orbit.

"We didn't expect anything less and couldn't have asked for anything more from the spacecraft and the team," said Robert T. Mitchell, program manager for the Cassini-Huygens mission at JPL. "This speaks volumes to the tremendous team that made it all happen."

Dr. Charles Elachi, JPL director and team leader on the radar instrument onboard Cassini, said, "It feels awfully good to be in orbit around the lord of the rings. This is the result of 22 years of effort, of commitment, of ingenuity, and that's what exploration is all about."

The mission will face another dramatic challenge in December, when the spacecraft will release the piggybacked Huygens probe - provided by the European Space Agency - which will plunge through the hazy atmosphere of Saturn's largest moon, Titan.

"This was America's night. This was NASA doing it right," said Dr. David Southwood, director of scientific programs for the European Space Agency. "They really gave those of us in Europe a challenge. We've got six months to go until we land on Titan. We're just praying that everything will go as well."

Julie Webster, Cassini-Huygens spacecraft team chief, said, "The spacecraft has been an incredible joy to fly. We stand on the shoulders of people who had 40 years of experience building and designing spacecraft."

Saturn is the sixth planet from the Sun. It is the second largest planet in our solar system, after Jupiter. The planet and ring system serve as a miniature model of the disc of gas and dust surrounding our early Sun that eventually formed the planets. Detailed knowledge of the dynamics of interactions among Saturn's elaborate rings and numerous moons will provide valuable data for understanding how each of the solar system's planets evolved.

Cassini traveled nearly 3.5 billion kilometers (2.2 billion miles) to reach Saturn after its launch from Cape Canaveral Air Force Station, Fla., on Oct. 15, 1997. During Cassini's four-year mission, it will execute 52 close encounters with seven of Saturn's 31 known moons.

The first images are expected to return Thursday morning. Science measurements gathered Wednesday are the closest ever obtained of Saturn. Those measurements may reveal details of the gravitational and magnetic fields that tell scientists about Saturn's interior.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. JPL designed, developed and assembled the Cassini orbiter.

For the latest images and more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .
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Old July-2nd-2004, 08:45 AM   #4
HenryMc
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Hey Sunny I can see your house from here
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Old July-2nd-2004, 08:56 AM   #5
tippy
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cool baby, that's one thing that irritates me about living in urban environs, you caint see nothing in the sky.
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Old July-2nd-2004, 09:01 AM   #6
Brian Olewnick
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Old July-2nd-2004, 09:09 AM   #7
Gary Sisco
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Did they pick up any Sun Ra transmissions while downloading the pictures?
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Old July-2nd-2004, 09:18 AM   #8
Slurpy
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Quote:
Originally Posted by Gary Sisco
Did they pick up any Sun Ra transmissions while downloading the pictures?

Well, Space is the place

For anyone who cares.....

How do you keep track of an object that's been hurled away from Earth to travel for years throughout the solar system? How do you know where it is, and how fast it's traveling?

The uplink and the downlink work together to solve these problems. Uplink uses powerful radio transmitters, and downlink uses sensitive receivers, both within the Deep Space Network (DSN). Cassini-Huygens can only be tracked because it carries a radio transmitter that sends signals to Earth. (This is true with all other interplanetary spacecraft as well.) The transmitter aboard Cassini is linked with its own radio receiver, so that they can both work together when needed.

The two main types of tracking data that are used with Cassini are ranging and the Doppler effect. Using these two data types, the navigators can accurately track the Cassini-Huygens spacecraft.

Ranging

Ranging determines the distance (range) from Earth to the spacecraft and back, by placing specially coded signals (called ranging tones) on the radio uplink, and recording the exact time as they go up. When the spacecraft receives them, it puts them on the downlink right away. When they come back to Earth, the exact time is noted again. So basically, the ranging computer knows what time it sent the tones, and it knows what time they came back.

Since the speed of the radio signals is known (they travel at the speed of light), the round-trip distance can then be computed.

There are other factors to consider, too. How long did it take for the ranging tones to "turn around" inside the spacecraft's electronics? That miniscule delay is calculated from pre-launch testing. How long did it take the ranging tones to travel through the cable from the computer in the Deep Space Network (DSN) signal-processing center out to the radio telescope antenna before leaving Earth? The DSN finds that value while calibrating the system prior to each tracking period. And how far did the Earth move while the ranging pulses were traveling to the spacecraft? The navigators draw upon data gathered over years and years of observations by the astronomical community.

Highly evolved computer programs within the ranging system process these data to determine the distance between Earth and the Cassini-Huygens spacecraft.

Optical Navigation

Even though the most common means to track the spacecraft use ranging and the Doppler effect, a third data type can come into play once the spacecraft arrives near or is in orbit around Saturn. Optical navigation involves having the Cassini orbiter capture images of Saturn's satellites, with the background stars visible. These images come on the downlink as what is known as telemetry data, and once received, they are analyzed by the navigators for a more precise analysis of the spacecraft's trajectory than is available through ranging and the Doppler effect alone. Using this "opnav" data, instructions can then be uplinked to the spacecraft in the form of command data to fine-tune the spacecraft's on-board schedule of science observations, or to fine-tune a direction to point its instruments.

All three of these types of data that Cassini-Huygens uses for navigation, are subject to the round-trip-light time of around three hours across the distance between Earth and Saturn.
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Old July-2nd-2004, 11:55 AM   #9
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Lots of info and pictures here: Cassini-Huygens
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Old September-10th-2004, 12:17 AM   #10
john williams
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Quote:
Originally Posted by BFrank
Lots of info and pictures here: Cassini-Huygens

New ring and new moon(s)

Last edited by john williams; September-10th-2004 at 12:18 AM.
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Old September-10th-2004, 01:15 AM   #11
Ron Thorne
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How interesting that I should see this thread tonight. Our oldest son just bought something last week that he's wanted since he was a boy ... his first telescope. We were just talking about Saturn (among other celestial bodies) this past weekend. I'll get a chance to enjoy using it later this month when we visit him and his wife and new baby (to come) in southern California. He bought a nice piece, a Celestron Advanced Series 9.25" SGT Schmidt/Cassegrain Reflector Telescope w/ XLT coatings.




He's dying to get proper couplings for some of his cameras to photograph what he's seeing with his naked eye.

Obviously, he won't get the kind of resolution acquired by Cassini, but considering the cost differential and the fact that it's earth-bound and in his back yard, we'll take it.

Thanks, BFrank.
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Old September-10th-2004, 01:48 AM   #12
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Wow. That's a serious piece of equipment.

Should provide MANY hours of fun.

I'm jealous.
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Old September-10th-2004, 02:19 AM   #13
Ron Thorne
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Yeah, he's like the proverbial "kid in the candy store" right now. He was so excited to get this piece of equipment and put it to use that he assembled it without the aid of an operator's manual, which was somehow overlooked in the packaging. He said that it was a bit of a complex task (that's a huge admission for Darren), but that he was determined to use it the same day he received it. That's my boy!

He was hunting down Pluto when we last spoke.
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Old September-10th-2004, 10:47 AM   #14
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Careful he doesn't point it at Uranus.
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Old September-10th-2004, 10:51 AM   #15
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What's the big deal? It's just a car.

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Old September-10th-2004, 12:44 PM   #16
Ron Thorne
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Quote:
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Careful he doesn't point it at Uranus.
He already has, as a matter of fact.

My son sent me this link to the European Space Agency which he feels makes the NASA site pale by comparison.
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