Cassini could rival Mars rovers

Analysis: Cassini could rival Mars rovers


By Phil Berardelli
United Press International


Washington, DC, Apr. 23 (UPI) -- A little more than two months from
now, perhaps sooner, the headlines about spacecraft exploring other
worlds will shift somewhat from the exploits of NASA's two Mars rovers
to another pair of probes now careening toward glorious Saturn.

If all goes well, the Cassini spacecraft will rendezvous with the
giant planet on July 1, after traveling nearly 1 billion miles, and
will begin a mission that could last for many years.

Launched from Kennedy Space Center in Florida on Oct. 15, 1997,
Cassini is set to train its sensitive instruments on Saturn's
atmosphere, its extraordinarily complex ring system and its array of
31 known moons. Six months later, in early January 2005, the European
Space Agency's Huygens probe, which has piggy-backed aboard Cassini,
will detach from the orbiter, plunge into the thick atmosphere of
Saturn's largest moon, Titan, and attempt to land on its surface.

Cassini is named for the Italian astronomer who, in the 17th century,
discovered four of Saturn's moons and, more famously, the strange gap
in the planet's ring system that is now named for him. Huygens is
named for the Dutch scientist and mathematician who helped improve the
quality of telescopes, also in the 17th century.

NASA officials have called Cassini-Huygens "one of the most ambitious
missions ever launched into space." Loaded with 18 exquisitely
sensitive instruments -- 12 on the orbiter and six on the probe --
that are capable of performing a variety of scientific measurements,
the twin craft have been equipped to investigate all the important
characteristics of the Saturn system that their builders could
anticipate.

Given the capability of the spacecraft, and given Saturn's formidable
list of unique characteristics, the tenure of Cassini-Huygens within
the Saturnian system promises to flood earthbound scientists, both
with discoveries to savor and more mysteries to ponder.

Even what scientists already know is amazing:

-- Second-largest Saturn is perhaps the most arresting sight in the
solar system. Its stunning rings are 185,000 miles in diameter -- more
than twice the size of Jupiter -- but only about a half-mile thick.

-- Its 31 known moons include Titan, which is larger than Mercury and
is the only moon in the solar system with its own atmosphere -- which
is thicker than Earth's atmosphere.

-- Saturn has the distinction of being the only known planet that is
less dense than water. That means if it could be placed in a gigantic
bathtub it actually would float.

-- Saturn has an extremely stormy atmosphere, outclassing even
Jupiter, with winds clocked at more than 1,100 miles per hour near its
equator.

-- The surface of Mimas has been scarred by a crater so big the impact
nearly shattered Saturn's small moon. Scientists think Mimas might
have sustained even larger impacts during the solar system's history,
and perhaps was broken up and gravitationally reassembled several
times.

-- Another of Saturn's moons, Iapetus, is bright and icy on one side
and dark and dusty on the other.

Still, the rings are what sets Saturn apart from the rest of the
planets in the solar system. Made up by billions and billions of ice
and rock particles of all sizes -- from small debris to boulders as
big as houses -- the rings orbit Saturn at varying speeds. They are so
big they would fill three-quarters of the distance between Earth and
the moon.

Although popular satellite images show only five main rings -- named
"A" through "E" -- and a secondary, "F" ring, there really are
hundreds of rings, all thought to be pieces of shattered comets,
asteroids or moons that broke apart because they swung a little too
close to Saturn.

Actually, Saturn's thin F ring could prove to be the most fascinating
-- and the key to the entire ring system -- because it seems to be
held in place by two tiny "shepherd" moons. Named Prometheus and
Pandora -- in keeping with the tradition of drawing from mythology for
newly discovered solar system members -- the moons act like a pair of
herding sheepdogs.

Planetary scientists, such as David Grinspoon of the Southwest
Research Institute in Boulder, Colo., are beginning to think Saturn's
ring system is a relatively temporary phenomenon. It might be,
Grinspoon said, that humans are merely fortunate to be living at a
time when Saturn's rings are so glorious. Perhaps in a matter of some
millions of years, they will dissipate, relegating Saturn to the
second-class status now occupied in the solar system by Uranus and
Neptune. Or, the rings have persisted because Prometheus and Pandora
preserve their integrity.

Cassini will attempt to learn more about the dynamics of the rings
during its operational lifetime, along with exploring the host of
intriguing facets that make up the real "Lord of the Rings."

--

Phil Berardelli is UPI's Science & Technology Editor. E-mail

"Steve Dufour" wrote in message
m...
snip
Launched from Kennedy Space Center in Florida on Oct. 15, 1997,
Cassini is set to train its sensitive instruments on Saturn's
atmosphere, its extraordinarily complex ring system and its array of
31 known moons. Six months later, in early January 2005, the European
Space Agency's Huygens probe, which has piggy-backed aboard Cassini,
will detach from the orbiter, plunge into the thick atmosphere of
Saturn's largest moon, Titan, and attempt to land on its surface.
snip

Land on the surface? I don't get it. I thought Saturn was gaseous?

--
BV.
www.iheartmypond.com

On Mon, 26 Apr 2004 13:30:34 -0400, in a place far, far away, "Benign
Vanilla" made the phosphor on my
monitor glow in such a way as to indicate that:


"Steve Dufour" wrote in message
om...
snip
Launched from Kennedy Space Center in Florida on Oct. 15, 1997,
Cassini is set to train its sensitive instruments on Saturn's
atmosphere, its extraordinarily complex ring system and its array of
31 known moons. Six months later, in early January 2005, the European
Space Agency's Huygens probe, which has piggy-backed aboard Cassini,
will detach from the orbiter, plunge into the thick atmosphere of
Saturn's largest moon, Titan, and attempt to land on its surface.
snip

Land on the surface? I don't get it. I thought Saturn was gaseous?

Read again. Land on Titan's surface.

Dude, read it again.



"Benign Vanilla" wrote in message
...

"Steve Dufour" wrote in message
m...
snip
Launched from Kennedy Space Center in Florida on Oct. 15, 1997,
Cassini is set to train its sensitive instruments on Saturn's
atmosphere, its extraordinarily complex ring system and its array of
31 known moons. Six months later, in early January 2005, the European
Space Agency's Huygens probe, which has piggy-backed aboard Cassini,
will detach from the orbiter, plunge into the thick atmosphere of
Saturn's largest moon, Titan, and attempt to land on its surface.
snip

Land on the surface? I don't get it. I thought Saturn was gaseous?

--
BV.
www.iheartmypond.com

Saturn is Gaseous. Titan however (where Huygens is going) is a solid
rocky body with a thick atmosphere.

In article ,
says...

"Steve Dufour" wrote in message
m...
snip
Launched from Kennedy Space Center in Florida on Oct. 15, 1997,
Cassini is set to train its sensitive instruments on Saturn's
atmosphere, its extraordinarily complex ring system and its array of
31 known moons. Six months later, in early January 2005, the European
Space Agency's Huygens probe, which has piggy-backed aboard Cassini,
will detach from the orbiter, plunge into the thick atmosphere of
Saturn's largest moon, Titan, and attempt to land on its surface.
snip

Land on the surface? I don't get it. I thought Saturn was gaseous?

--
BV.
www.iheartmypond.com

"Rand Simberg" wrote in message
...
On Mon, 26 Apr 2004 13:30:34 -0400, in a place far, far away, "Benign
Vanilla" made the phosphor on my
monitor glow in such a way as to indicate that:


"Steve Dufour" wrote in message
om...
snip
Launched from Kennedy Space Center in Florida on Oct. 15, 1997,
Cassini is set to train its sensitive instruments on Saturn's
atmosphere, its extraordinarily complex ring system and its array of
31 known moons. Six months later, in early January 2005, the European
Space Agency's Huygens probe, which has piggy-backed aboard Cassini,
will detach from the orbiter, plunge into the thick atmosphere of
Saturn's largest moon, Titan, and attempt to land on its surface.
snip

Land on the surface? I don't get it. I thought Saturn was gaseous?

Read again. Land on Titan's surface.

Oops. Thanks for pointhing that out. I dunno how I missed that.

--
BV.
www.iheartmypond.com

"Steve Dufour" wrote in message
m...
Analysis: Cassini could rival Mars rovers


By Phil Berardelli
United Press International


Washington, DC, Apr. 23 (UPI) -- A little more than two months from
now, perhaps sooner, the headlines about spacecraft exploring other
worlds will shift somewhat from the exploits of NASA's two Mars rovers
to another pair of probes now careening toward glorious Saturn.

If all goes well, the Cassini spacecraft will rendezvous with the
giant planet on July 1, after traveling nearly 1 billion miles, and
will begin a mission that could last for many years.

Launched from Kennedy Space Center in Florida on Oct. 15, 1997,
Cassini is set to train its sensitive instruments on Saturn's
atmosphere, its extraordinarily complex ring system and its array of
31 known moons. Six months later, in early January 2005, the European
Space Agency's Huygens probe, which has piggy-backed aboard Cassini,
will detach from the orbiter, plunge into the thick atmosphere of
Saturn's largest moon, Titan, and attempt to land on its surface.


All very well, but there won't be any pictures from Titan, so the general
public won't feel very 'involved' with this mission.

"Uddo Graaf" wrote in message
...

"Steve Dufour" wrote in message
m...
Analysis: Cassini could rival Mars rovers


By Phil Berardelli
United Press International


Washington, DC, Apr. 23 (UPI) -- A little more than two months from
now, perhaps sooner, the headlines about spacecraft exploring other
worlds will shift somewhat from the exploits of NASA's two Mars rovers
to another pair of probes now careening toward glorious Saturn.

If all goes well, the Cassini spacecraft will rendezvous with the
giant planet on July 1, after traveling nearly 1 billion miles, and
will begin a mission that could last for many years.

Launched from Kennedy Space Center in Florida on Oct. 15, 1997,
Cassini is set to train its sensitive instruments on Saturn's
atmosphere, its extraordinarily complex ring system and its array of
31 known moons. Six months later, in early January 2005, the European
Space Agency's Huygens probe, which has piggy-backed aboard Cassini,
will detach from the orbiter, plunge into the thick atmosphere of
Saturn's largest moon, Titan, and attempt to land on its surface.


All very well, but there won't be any pictures from Titan, so the general
public won't feel very 'involved' with this mission.

That's a shame. I guess every ounce counts, but it would be great if every
probe carried at least a 2-3 megapixel camera, and enough transmitting power
to either reach earth (no matter how slowly) or broadcast to an orbiting
probe to send picture back.

I think if I win a huge lottery some day (of course Step 1 is that I will
start playing the lottery) I will create a company that will do R&D to make
very small, very light probes that can be produced en masse cheaply. Each
carrying a simple experiment, even something as simple as just a camera. It
would be fantastic to launch these things to many plants, moons, etc. Let
them land, and just roam around taking pictures.

--
BV.
www.iheartmypond.com

Steve Dufour wrote:

Analysis: Cassini could rival Mars rovers

Warning: this is a bit of a rant. So if you don't like hearing things
you may vehemently disagree with, stop reading now! :-)

I hope this headline is true, and I am very much looking forward to the
probe descending into Titan.

But... Cassini is a *very* expensive mission that is in the model of
Galileo at Jupiter. I think we didn't spend our money wisely on Galileo
and I'm concerned the same is going to be true of Cassini.

Here's the problem: ignoring the one-time probes (which I support), the
idea of putting a large expensive satellite into orbit around Jupiter or
Saturn for many years seems to yield relatively little science return
for the dollar. It's like having multiple flybys of the system, like
launching 50 Voyagers. But is that all that interesting? These systems
have been explored already via this method. Sure, Cassini is "better"
and will allow long term study of changes in the atmosphere of Saturn
and it's ring system and help map the radiation environment. I don't
mean to trivialize those things, but given that these probes are taking
enormous resources for many years I can't help but wonder if we could
have had a higher science return by sending multiple smaller probes,
each targeted at a specific moon, or heaven forbid, science question.

They have implied in this PR piece that Cassini will have the same level
of impact on our understanding of Saturn and it's moon system as MER has
at Mars. Here's my standard of comparison: compare an introductory
astronomy textbook before Galileo and after. How much really had to be
rewritten? How much needed to be expanded on? It is quite clear that
MER will produce major changes in the Mars chapters of these texts.
Sure, I recognize that not all science has to be earth shattering enough
to change an elementary text to be good science, and that little is.
But given the primitive state of our knowledge, the enormous cost in
both dollars and years of effort that went into Galileo and now Cassini,
it seems to be that we might have adopted a strategy that would have
provided a lot more exploration for the buck.

MER is doing amazing science; it is answering fundamental questions that
have been dogging us for years. I guess that's a tough act to follow,
but perhaps when we plan future missions it should be the gold standard...

I don't mean to be negative; it's just some food for thought.

--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)

SkyTools Software for the Observer:
http://www.skyhound.com/cs.html

Skyhound Observing Pages:
http://www.skyhound.com/sh/skyhound.html

To reply have a physician remove your spleen

Craig wrote:

Saturn is Gaseous. Titan however (where Huygens is going) is a solid
rocky body with a thick atmosphere.

Well, it may have oceans.

Paul