Saturn/Cassini-Huygens close to sun

Starry-Nite wrote:

(without hitting
any of Saturn's 31 known moons)

Nor, fortunately, any unknown ones :-)

David Knisely wrote:

sirius posted:

Why did JPL choose a mission plan that caused Cassini to arrive at
Saturn close to it's solar conjunction date?

Because the launch date and arrival dates were dictated by when the various
planets would be in the right locations. These planets were needed to give a
series of "gravity assist" boosts in velocity to Cassini as it flew through
space to get it to Saturn without using a gigantic (and thus unavailable)
launch vehicle. It passed by Venus twice, the Earth once, and Jupiter before
gaining enough speed (and the proper direction) to reach Saturn.

I forgot about the planetary gravity assists, which were necessary
because of Cassini's formidable mass. Do you know when the next
favorable planetary positioning will occur for a similar mission to
Saturn? Eventually we'll have to build a suitable booster for large
planetary spacecraft. We can't keep using the gravity assist method or
we'll change the orbits of the planets. :-)

BTW- Is there a motion video of Cassini's path through the solar system
on the Net?


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David Knisely wrote:

sirius posted:

Why did JPL choose a mission plan that caused Cassini to arrive at
Saturn close to it's solar conjunction date?

Because the launch date and arrival dates were dictated by when the various
planets would be in the right locations. These planets were needed to give a
series of "gravity assist" boosts in velocity to Cassini as it flew through
space to get it to Saturn without using a gigantic (and thus unavailable)
launch vehicle. It passed by Venus twice, the Earth once, and Jupiter before
gaining enough speed (and the proper direction) to reach Saturn.

I forgot about the planetary gravity assists, which were necessary
because of Cassini's formidable mass. Do you know when the next
favorable planetary positioning will occur for a similar mission to
Saturn? Eventually we'll have to build a suitable booster for large
planetary spacecraft. We can't keep using the gravity assist method or
we'll change the orbits of the planets. :-)

BTW- Is there a motion video of Cassini's path through the solar system
on the Net?


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Starry-Nite wrote:

sirius wrote...
Why did JPL choose a mission plan that caused Cassini to arrive at
Saturn close to it's solar conjunction date?

To gain the momentum needed to get to Saturn we set up one hell of a
bank shot, stealing momentum from each planet along our way to boost
our speed. In this Super Billiards match we computed the orbits such
that we missed our Moon, flew by Venus, flew by Venus (again), swung
by Earth (far enough out to keep the Pu away from us... sorry, I'm
griping about another thread), missed our Moon two more times, flew by
Jupiter (with a path that complemented the science of the Galileo
mission, without hitting any of Jupiter's 61 known moons), passed
Phoebe, flew IN BETWEEN he F and G rings of Saturn (without hitting
any of Saturn's 31 known moons), and entered into a path that allow us
to develop an Saturnian orbit in resonance with Titan.

I have heard that Opportunity (MER-B) ending up in Eagle crater during
its bouncing landing was, "A Cosmic Hole in One".

Pikers!

Rolling into the crater was an accident. A really NICE accident, but
still, an unplanned event.

Cassini's incredible thread-the-needle trick was 110% PLANNED! (The
extra 10% is for the overtime and a helpful bit of luck!)

Immediately after SOI (Saturn Orbital Insertion), someone at Mission
Control joked that we did such a great job of hitting the slot that we
could skip the July 3rd correction maneuver. Everyone in the room
laughed - it was a tension release. Of course, we ALWAYS have to do
some orbital cleanup after a big event. Except, this time we are SO
CLOSE to being right on the button that The Powers that Make the Big
Decisions are (as I write this) really considering skipping Saturday's
correction!

Next time you play billiards, try to duplicate THAT shot! Then try to
make that shot with your boss' boss' boss watching, and with press
from around the world camped in the next room!

After that incredible accomplishment, and without hitting anything
between here and there, and now being set up for a really cool four
year mission - we can live with a bit of communications scheduling.
Besides, the chaps at the Deep Space Net consider it to be a personal
challenge!

Go Cassini!

(And if I may trumpet our own horn; Yo, JPL - Hot Damn!)

¤ Clear skies & a star to steer by! Michael ¤

Isaac Newton would be proud of you all.


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Starry-Nite wrote:

sirius wrote...
Why did JPL choose a mission plan that caused Cassini to arrive at
Saturn close to it's solar conjunction date?

To gain the momentum needed to get to Saturn we set up one hell of a
bank shot, stealing momentum from each planet along our way to boost
our speed. In this Super Billiards match we computed the orbits such
that we missed our Moon, flew by Venus, flew by Venus (again), swung
by Earth (far enough out to keep the Pu away from us... sorry, I'm
griping about another thread), missed our Moon two more times, flew by
Jupiter (with a path that complemented the science of the Galileo
mission, without hitting any of Jupiter's 61 known moons), passed
Phoebe, flew IN BETWEEN he F and G rings of Saturn (without hitting
any of Saturn's 31 known moons), and entered into a path that allow us
to develop an Saturnian orbit in resonance with Titan.

I have heard that Opportunity (MER-B) ending up in Eagle crater during
its bouncing landing was, "A Cosmic Hole in One".

Pikers!

Rolling into the crater was an accident. A really NICE accident, but
still, an unplanned event.

Cassini's incredible thread-the-needle trick was 110% PLANNED! (The
extra 10% is for the overtime and a helpful bit of luck!)

Immediately after SOI (Saturn Orbital Insertion), someone at Mission
Control joked that we did such a great job of hitting the slot that we
could skip the July 3rd correction maneuver. Everyone in the room
laughed - it was a tension release. Of course, we ALWAYS have to do
some orbital cleanup after a big event. Except, this time we are SO
CLOSE to being right on the button that The Powers that Make the Big
Decisions are (as I write this) really considering skipping Saturday's
correction!

Next time you play billiards, try to duplicate THAT shot! Then try to
make that shot with your boss' boss' boss watching, and with press
from around the world camped in the next room!

After that incredible accomplishment, and without hitting anything
between here and there, and now being set up for a really cool four
year mission - we can live with a bit of communications scheduling.
Besides, the chaps at the Deep Space Net consider it to be a personal
challenge!

Go Cassini!

(And if I may trumpet our own horn; Yo, JPL - Hot Damn!)

¤ Clear skies & a star to steer by! Michael ¤

Isaac Newton would be proud of you all.


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starman wrote in message ...
Starry-Nite wrote:
sirius wrote...
Why did JPL choose a mission plan that caused Cassini to arrive at
Saturn close to it's solar conjunction date?

To gain the momentum needed to get to Saturn we set up one hell of a
bank shot, stealing momentum from each planet along our way to boost
our speed.

(snip)

Go Cassini!

(And if I may trumpet our own horn; Yo, JPL - Hot Damn!)

¤ Clear skies & a star to steer by! Michael ¤

Isaac Newton would be proud of you all.

Yo, Ike! Hot Damn! ~Gramps

starman wrote in message ...
Starry-Nite wrote:
sirius wrote...
Why did JPL choose a mission plan that caused Cassini to arrive at
Saturn close to it's solar conjunction date?

To gain the momentum needed to get to Saturn we set up one hell of a
bank shot, stealing momentum from each planet along our way to boost
our speed.

(snip)

Go Cassini!

(And if I may trumpet our own horn; Yo, JPL - Hot Damn!)

¤ Clear skies & a star to steer by! Michael ¤

Isaac Newton would be proud of you all.

Yo, Ike! Hot Damn! ~Gramps

"sirius" wrote:

s Why did JPL choose a mission plan that caused Cassini to
s arrive at Saturn close to it's solar conjunction date?

In addition to waiting for favorable planetary alignments, the arrival date
and trajectory to Saturn were specifically selected to accommodate
a flyby of Phoebe - the only opportunity to study Phoebe during the mission.

"sirius" wrote:

s Why did JPL choose a mission plan that caused Cassini to
s arrive at Saturn close to it's solar conjunction date?

In addition to waiting for favorable planetary alignments, the arrival date
and trajectory to Saturn were specifically selected to accommodate
a flyby of Phoebe - the only opportunity to study Phoebe during the mission.

"Morris Jones" wrote in message
...
Florian wrote:
Something that surprises me about the Cassini-Huygens probe is how close
Saturn is to the sun as viewed from Earth right now. Tonight for the
orbit insertion Saturn is about 6=B0 from the sun. In a week it looks
like Saturn will pass behind the sun as viewed from Earth. How does the
close proximity of Saturn to the sun effect communication with the
probe?

My wife Jane is at JPL right now working the newsroom. Last week she said
that in just a few days (was it Saturday?) they will go into a two week
quiet period for solar conjunction.

Hi Mojo,

I've been watching the wires for some of Janes eloquent, yet pithy prose,
but so far I have come up blank. Where should I be looking.