Cassini Mission prepares for Grand Finale and destruction in Saturn

Brian G Turner

Fantasist & Futurist
Staff member
Supporter
Joined
Nov 23, 2002
Messages
21,616
Location
Highlands
#1
The Cassini probe around Saturn is about to make a course change that will result in some of the cloest approaches yet to the gas giant. And then, in September, when its fuel has almost run out, it will plunge into Saturn's atmosphere for one last mission:

Cassini: Mission to Saturn: Overview

After almost 20 years in space, NASA's Cassini spacecraft begins the final chapter of its remarkable story of exploration: its Grand Finale.

Between April and September 2017, Cassini will undertake a daring set of orbits that is, in many ways, like a whole new mission. Following a final close flyby of Saturn's moon Titan, Cassini will leap over the planet's icy rings and begin a series of 22 weekly dives between the planet and the rings.

...

On the final orbit, Cassini will plunge into Saturn’s atmosphere, sending back new and unique science to the very end. After losing contact with Earth, the spacecraft will burn up like a meteor, becoming part of the planet itself.
 

Alexa

traveller space dreamer
Joined
Oct 29, 2004
Messages
2,117
Location
Somewhere in the Quad
#4
Cassini's First Dive Between Saturn and Its Rings. After the first-ever dive through the narrow gap between the planet Saturn and its rings, NASA's Cassini spacecraft called home to mission control at NASA’s Jet Propulsion Laboratory in Pasadena, California. See highlights from the scene at JPL on April 26-27, 2017, and some of the first raw images the spacecraft sent back from its closest-ever look at Saturn’s atmosphere. For more information about Cassini and its “Grand Finale,” visit Cassini: The Grand Finale .
This unprocessed image shows features in Saturn's atmosphere from closer than ever before. The view was captured by NASA's Cassini spacecraft during its first Grand Finale dive past the planet on April 26, 2017.

 

Vertigo

Mad Mountain Man
Supporter
Joined
Jun 29, 2010
Messages
7,160
Location
Scottish Highlands
#8

Vertigo

Mad Mountain Man
Supporter
Joined
Jun 29, 2010
Messages
7,160
Location
Scottish Highlands
#13
Somebody asked why they had to crash it. Apparently scientists wanted to be sure that any proof of life will be not contaminated from the Earth.
That's right because if it had crashed into a cold world like Enceladus then there was a remote chance that terran microbes may have contaminated it. By burning up at incredibly high temperatures in the atmosphere of Saturn they can be very certain any microbes on Cassini will have been sterilised.

Interesting that we've never worried too much about that on Mars or Titan when it comes to landing probes...
 

Dave

Wherever I Am, I'm There
Staff member
Supporter
Joined
Jan 5, 2001
Messages
17,783
Location
Way on Down South, London Town
#14
Interesting that we've never worried too much about that on Mars or Titan when it comes to landing probes...
I agree, the early space programme was incredibly worried about contagion from space, and very careful about decontamination on the return of astronauts, but little thought given to, the real threat from, sending and landing probes.

Does anyone know when they will release the data taken during the journey through the atmosphere?
 

Vertigo

Mad Mountain Man
Supporter
Joined
Jun 29, 2010
Messages
7,160
Location
Scottish Highlands
#15
I agree, the early space programme was incredibly worried about contagion from space, and very careful about decontamination on the return of astronauts, but little thought given to, the real threat from, sending and landing probes.

Does anyone know when they will release the data taken during the journey through the atmosphere?
I don't think the data will be anything very spectacular for laymen; I suspect it will mostly be information on the make up of the upper atmosphere. Also there's only a few minutes of data before the wobble caused by the atmosphere resulted in loss of contact. Though apparently even that lasted longer than expected.

On the contamination thing I agree except it's not just the early programs that are 'guilty' of this and this is what I find a little irritating about the given explanation:

The space agency had no other choice. Cassini was nearly out of fuel and had already been stretched years beyond its intended mission duration. Keeping it going risked potentially contaminating one of Saturn’s moons — like Enceladus, an ice world that has some ingredients for life, or Titan, a dynamic moon where it rains methane — with microbes from Earth.
You see it was this very same mission - Cassini-Huygens to give it it's full name - that landed the Huygens probe on Titan, so had Cassini crashed on Titan it couldn't really have done any more damage than Huygens has already done. Actually less, as Titan has an atmosphere crashing Cassini there would have resulted in it buring up unlike Huygens' controlled parachute descent.

Surely the real reason is that it was running out of fuel so why not use that last bit of fuel to gather some final data from Saturn's atmosphere. Isn't that a good enough reason?
 

Dave

Wherever I Am, I'm There
Staff member
Supporter
Joined
Jan 5, 2001
Messages
17,783
Location
Way on Down South, London Town
#16
You see it was this very same mission - Cassini-Huygens to give it it's full name - that landed the Huygens probe on Titan, so had Cassini crashed on Titan it couldn't really have done any more damage than Huygens has already done. Actually less, as Titan has an atmosphere crashing Cassini there would have resulted in it buring up unlike Huygens' controlled parachute descent.
Maybe they thought Huygens was sufficiently sterile. Satellites and spacecraft are built in the cleanest conditions imaginable since even a small particle of dust can cause damage - so negative air conditioning with special filters and people wearing disposable shoes, gloves, face masks and clothes. (I'm assuming Huygens was inside the outer casing of Cassini, but that Cassini itself would have been exposed to Earth atmosphere during its launch. That could be wrong, in which case I have no more explanation for the statement than you.)
 

Stephen Palmer

author of novels
Supporter
Joined
Dec 22, 2009
Messages
4,199
Location
Shropshire
#18
You see it was this very same mission - Cassini-Huygens to give it it's full name - that landed the Huygens probe on Titan, so had Cassini crashed on Titan it couldn't really have done any more damage than Huygens has already done. Actually less, as Titan has an atmosphere crashing Cassini there would have resulted in it buring up unlike Huygens' controlled parachute descent.
I had the impression that life on Titan was virtually zero chance because of the temperature, whereas life on Enceladus - at the deeps of the ocean - is far more likely as it'll be quite warm there.
 

Vertigo

Mad Mountain Man
Supporter
Joined
Jun 29, 2010
Messages
7,160
Location
Scottish Highlands
#19
Maybe they thought Huygens was sufficiently sterile. Satellites and spacecraft are built in the cleanest conditions imaginable since even a small particle of dust can cause damage - so negative air conditioning with special filters and people wearing disposable shoes, gloves, face masks and clothes. (I'm assuming Huygens was inside the outer casing of Cassini, but that Cassini itself would have been exposed to Earth atmosphere during its launch. That could be wrong, in which case I have no more explanation for the statement than you.)
A good point: you may well be right about that.
I had the impression that life on Titan was virtually zero chance because of the temperature, whereas life on Enceladus - at the deeps of the ocean - is far more likely as it'll be quite warm there.
Yeah I agree but the scientists are quoted as saying they didn't want to risk contaminating Enceladus or Titan. That's what I thought was slightly dodgy logic but, as Dave says, maybe there was much less chance of Huygens being contaminated.

Mind you, as discussed on a previous occasion, if we do find life on Enceladus or anywhere else, unless it has a radically different makeup to terran life it will instantly be blamed on contamination no matter how careful we are. Or attributed to panspermia.
 

Similar threads

Top