Cassini is now in orbit of Saturn

[yaohua2000]

[Manchurian Taikonaut]

yes, should be very good
http://ciclops.lpl.arizona.edu/PR/20...R2004C05A.html
http://www.alumni.caltech.edu/~madler/cassini.jpg

let us hope everything does well

[Grand_Lunar]

Got a problem with kilometers? :P That would still make an impression.
Have you ever read the book 2001? (Clarke wrote it while the film was in production, making changes along the way.) Anyway, the book had the Discovery going on to Saturn after Jupiter. I mention it here, because often, life ends up imitating art. I felt that the Galileo mission was like 2010 in a way (a spinning section of a spacecraft included!). Of course, it was a machine that did the adventure, but still, its almost like going on the ride. And now Cassini is about to take us on another space odessy! Wonder if it will snap some images of Iapetus? Of course, the BIG event is when the Huygens probes takes some snapshots of the smog moon Titan. Ooo, I can hardly wait to see what's there! Be prepared for anything!

[PeteB]

Grand_Lunar:

There will be an Iapetus flyby earlier than first planned. When the Huygens entry was pushed back from November '04 to January '05, 2 additional early orbits with close Titan encounters were added. By chance the orbit on which the Huygens probe is released comes relatively close to Iapetus. Otherwise, the close flyby (1000-2000 km) of that satellite comes in September 2007.

Here are some links I posted in another thread.

Diagram of the early orbits
http://solarsystem.dlr.de/PG/cassini...ini_soi2tc.JPG

Geometry of the July 2 flyby of Titan
http://solarsystem.dlr.de/PG/cassini.../titan_t00.JPG

December 13 Titan encounter. I don’t know why but the Huygens entry site is shown at the right longitude (~160 E) but wrong latitude (18 N). It should be at 11 S., just below the dark patch (hydrocarbon lake ??)
http://solarsystem.dlr.de/PG/cassini.../titan_t0b.JPG

QuickTime animations of the entire orbit tour (255 MB! – about 40 minutes to download on DSL), all Iapetus views during the mission, and a detailed version of the Dec 31 –Jan 01 (UTC) flyby. This part of Iapetus was either not imaged or at only ~20-30 km/pixel by Voyager. The best Cassini images should be <400 m/pixel.
http://solarsystem.dlr.de/PG/cassini...on/orbit.shtml

[yaohua2000]

Cassini's speed related to the Sun from 1997-10-15 16:00:01 UT to 2008-08-08 16:00:00 UT computed by JPL HORIZONS System.

[kucharek]

Yaohua, you should try not to inline large images. Not everyone is coming here on DSL and it also stretches the layout of the page. Now I've to horizontal scoll to read the postings.

With my limited knowledge of Japanese, I find "Saturn" (5th and 6th character "Earth", "Star") in the headline and the last one is "Chart"
The second one may mean "west".

BTW, do you know that David Harland's great book on lunar exploration, "Exploring the Moon", was published in Chinese some time ago?
http://homepage.ntlworld.com/dave.harland/
http://homepage.ntlworld.com/dave.ha...tM-Chinese.jpg

Regards

Harald

[yaohua2000]

Yaohua, you should try not to inline large images. Not everyone is coming here on DSL and it also stretches the layout of the page. Now I've to horizontal scoll to read the postings.

The image above is not very large in size. It's only 23.2 KB.

With my limited knowledge of Japanese, I find "Saturn" (5th and 6th character "Earth", "Star") in the headline and the last one is "Chart"
The second one may mean "west".

You were correct. The first 3 or 4 characters is "Cassini", 7th to 9th characters is "probe" or "spacecraft", 10th and 11th is "related to", 12th and 13th is "the Sun", 14th and 15th is "speed" or "velocity", the last 3 characters is "chart"

BTW, do you know that David Harland's great book on lunar exploration, "Exploring the Moon", was published in Chinese some time ago?
http://homepage.ntlworld.com/dave.harland/
http://homepage.ntlworld.com/dave.ha...tM-Chinese.jpg

I'm afraid I've not heard of the book yet. ops:

[kucharek]

BTW, do you know that David Harland's great book on lunar exploration, "Exploring the Moon", was published in Chinese some time ago?
http://homepage.ntlworld.com/dave.harland/
http://homepage.ntlworld.com/dave.ha...tM-Chinese.jpg

I'm afraid I've not heard of the book yet. ops:

Here are reviews of the english original:
http://www.amazon.com/exec/obidos/ASIN/1852330996
If you're interested, I can ask David for publisher details.

Harald

[Manchurian Taikonaut]

Chinese studying space have started to grow, but still I feel more people believe in Astrology and Magic...like Americans who have faith in the face on Mars and the living Elvis on the moon!! . I've often wondered why some of the older people working in the US space program never get any rest, they have worked on the moon missions, the Viking and so on. So if the US is so keep on saving money why don't NASA send some of their cumbersome or costly projects to HongKong , Beijing and other places where they can do it for a cheap and fast and then have some extra money for their other explorations and keep their own jobs and space projects going, plus they can give some of their older staffs a good vacation.
I guess some NASA workers would rather get other projects going and this space-tourism moving before they can take a holiday?

Cassini hope it does great, wishing them luck!!

[Mars]

Chinese studying space have started to grow, but still I feel more people believe in Astrology and Magic...like Americans who have faith in the face on Mars and the living Elvis on the moon!! . I've often wondered why some of the older people working in the US space program never get any rest, they have worked on the moon missions, the Viking and so on. So if the US is so keep on saving money why don't NASA send some of their cumbersome or costly projects to HongKong , Beijing and other places where they can do it for a cheap and fast and then have some extra money for their other explorations and keep their own jobs and space projects going, plus they can give some of their older staffs a good vacation.
I guess some NASA workers would rather get other projects going and this space-tourism moving before they can take a holiday?

Cassini hope it does great, wishing them luck!!

Too much politics involved, Unfortunatly.

[JohnOwens]

Cassini's speed related to the Sun from 1997-10-15 16:00:01 UT to 2008-08-08 16:00:00 UT computed by JPL HORIZONS System.

Am I the only one feeling the urge to convert this back into data and play the part after the middle of this year through an audio device and listen to what Cassini will "sound" like?

[Grand_Lunar]

Cassini's speed related to the Sun from 1997-10-15 16:00:01 UT to 2008-08-08 16:00:00 UT computed by JPL HORIZONS System.

Am I the only one feeling the urge to convert this back into data and play the part after the middle of this year through an audio device and listen to what Cassini will "sound" like?

You mean like the data from Voyager and Galileo? Nope, your not the only one. I'd like to hear that too. It'd be wild to see (hear) if each planet had its own "voice". Guess in space we can hear you scream. Or in this case, "sing". 8)

[JohnOwens]

Cassini's speed related to the Sun from 1997-10-15 16:00:01 UT to 2008-08-08 16:00:00 UT computed by JPL HORIZONS System.

Am I the only one feeling the urge to convert this back into data and play the part after the middle of this year through an audio device and listen to what Cassini will "sound" like?

You mean like the data from Voyager and Galileo? Nope, your not the only one. I'd like to hear that too. It'd be wild to see (hear) if each planet had its own "voice". Guess in space we can hear you scream. Or in this case, "sing". 8)

No, it's actually different from what you're talking about. If you check the graph in the link, it's Cassini's orbital velocity (measured relative to the Sun). It isn't a planetary thing at all, nor a radio thing. Just a manmade orbital oscillation that hasn't even happened yet.

Added: Of course, yeah, I suppose it would help if the server with the linked image was up and available. :-?

[Manchurian Taikonaut]

Wonderful image

http://chandra.harvard.edu/photo/200...aturn_comp.jpg

[ToSeek]

Cassini images clumps in F ring

[Swift]

Cassini images clumps in F ring

And that's from 63 million miles away. 8)

[Manchurian Taikonaut]

the real picture of what's going on!

http://saturn.jpl.nasa.gov/operation...sini_today.jpg

84 days to go

[yaohua2000]

the real picture of what's going on!

http://saturn.jpl.nasa.gov/operation...sini_today.jpg

84 days to go

I wrote an asp.net page which displays the distance from Cassini-Huygens to Saturn in realtime. 8)

[Manchurian Taikonaut]

distance in real time, great idea!


here's the latest images from Saturn probe

saturn view

[yaohua2000]

Cassini is only 50 million kilometers from Saturn on 2004-Mar-22 at 07:42:14 UT in SCET without Light Time Correction.

[tracer]

Just for my edjumacation here:

Is Cassini going to insert itself into orbit around Saturn by the conventional method of doing a big ol' rocket burn, or is it going to do something more tricky like aerobraking?

[kucharek]

Just for my edjumacation here:

Is Cassini going to insert itself into orbit around Saturn by the conventional method of doing a big ol' rocket burn, or is it going to do something more tricky like aerobraking?

No aerobraking.

Harald

[AK]

Just for my edjumacation here:

Is Cassini going to insert itself into orbit around Saturn by the conventional method of doing a big ol' rocket burn, or is it going to do something more tricky like aerobraking?

Rocket.

[tracer]

Hmmm ... how much delta-V will Cassini have to undergo to slow down from the speed it's going to have when it arrives at Saturn to the speed it needs to be going in order to orbit Saturn? Just how big of a rocket pack are we talking about here?

[Hamlet]

Hmmm ... how much delta-V will Cassini have to undergo to slow down from the speed it's going to have when it arrives at Saturn to the speed it needs to be going in order to orbit Saturn? Just how big of a rocket pack are we talking about here?

Here's an excerpt from here:

On arrival at Saturn, Cassini will make its closest approach to the planet, passing only 20 000 km above the cloud tops. It will fire one of its two redundant engines on 1 July 2004 for 96 min to slow its speed by 622 m/s for SOI; braking into a 1.33x178 Saturn radii (RS), 148-day, 16.8° orbit will consume 830 kg of the main propellant supply. A 50-min, 335 m/s burn 13 days after apoapsis of the post-SOI orbit will raise periapsis to 8.2 RS to target Cassini for a Titan encounter and Huygens' entry on 27 November 2004. If any problem with the spacecraft or ground system prevents execution of the Probe mission on the first Titan pass, a decision can be made as late as a few days before Probe separation to delay until the second Titan encounter on 14 January 2005.

Looks to be a total of 957 m/s of delta-V.

[tlbs101]

Take a look at this site. There is a graphic of the orbital insertion maneuver.

http://saturn.jpl.nasa.gov/operation...rn-arrival.cfm

I did some calculations. Right now the approach speed is about 41,000 km/hr. On June 30th, the approach speed will increase to 41,500 km/hr. This is the weird part -- even with a 97 minute retro-burn, the actual SPEED of Cassini will INCREASE to almost 50,000 km/hr, then "slow" to about 46,500 km/hr.

BUT we are talking VELOCITY here. Look at the OIM diagram on that web page. Notice the difference between the entry angle and exit angle -- almost 90 degrees! That represents a total VELOCITY change (with respect to the Earth) of almost ALL of the speed, so even though the actual SPEED increases, the speed component of the velocity with respect to the Earth, is reduced to almost nothing. Angular momentum is conserved and Cassini is in orbit around Saturn

Ain't orbital mechanics wonderful?
8)

[tracer]

braking into a 1.33x178 Saturn radii (RS), 148-day, 16.8° orbit will consume 830 kg of the main propellant supply. A 50-min, 335 m/s burn 13 days after apoapsis of the post-SOI orbit will raise periapsis to 8.2 RS to target Cassini for a Titan encounter and Huygens' entry on 27 November 2004.

Interesting ... Cassini's going to have to speed up at apoapsis to raise its periapsis distance, and it's going to have to impart nearly half as much delta-V to itself to accomplish this as it will to slow itself down to Saturn-orbital speed to begin with.

I wonder why they didn't just aim for an initial periapsis distance of 8.2 RS to begin with. Did they want to get one really really close pass at Saturn before they settled into their rest-of-the-mission orbit?

[ToSeek]

Cassini images spots on Saturn

[ToSeek]

braking into a 1.33x178 Saturn radii (RS), 148-day, 16.8° orbit will consume 830 kg of the main propellant supply. A 50-min, 335 m/s burn 13 days after apoapsis of the post-SOI orbit will raise periapsis to 8.2 RS to target Cassini for a Titan encounter and Huygens' entry on 27 November 2004.

Interesting ... Cassini's going to have to speed up at apoapsis to raise its periapsis distance, and it's going to have to impart nearly half as much delta-V to itself to accomplish this as it will to slow itself down to Saturn-orbital speed to begin with.

I wonder why they didn't just aim for an initial periapsis distance of 8.2 RS to begin with. Did they want to get one really really close pass at Saturn before they settled into their rest-of-the-mission orbit?

Someone who can really do the math can correct me, but I don't think it's that simple. If Cassini tried to come in with an initial periapsis of 8.2 RS, I believe it would take significantly more propellant to get it into orbit - even more than the apoapsis burn. The deeper into Saturn's gravity well it goes, the less propellant it has to burn to stay in it.

[R.A.F.]

ToSeek...man you are quick...I got the JPL e-mail about the spots on Saturn less than 10 minutes ago...and you already have it here.