Updates Cassini Mission News and Updates

[BrianJ]

Scenario for Cassini at Saturn 30th Aug.2017, data from JPL Horizons.
Required:
Cassini add-on https://www.orbithangar.com/searchid.php?ID=516
Spacecraft3.dll

BEGIN_DESC

END_DESC

BEGIN_ENVIRONMENT
  System Sol
  Date MJD 57995.5069203252
END_ENVIRONMENT

BEGIN_FOCUS
  Ship Cassini
END_FOCUS

BEGIN_CAMERA
  TARGET Cassini
  MODE Extern
  POS 6.921468 -22.425264 -38.918862
  TRACKMODE GlobalFrame
  FOV 30.00
END_CAMERA

BEGIN_HUD
  TYPE Surface
END_HUD

BEGIN_MFD Left
  TYPE Surface
  SPDMODE 1
END_MFD

BEGIN_MFD Right
  TYPE Orbit
  PROJ Ship
  FRAME Equator
  REF Saturn
END_MFD

BEGIN_SHIPS
Cassini:Spacecraft\Spacecraft3
  STATUS Orbiting Saturn
  RPOS -145916597.743 748316713.791 -1019802967.907
  RVEL 970.9824 971.3967 986.3240
  AROT -1.235 -9.170 -80.488
  AFCMODE 7
  PRPLEVEL 0:0.240000
  NAVFREQ 402 94
  RCS 1
  CTRL_SURFACE 1
  CONFIGURATION 1
  CURRENT_PAYLOAD 1
END
END_SHIPS

BEGIN_ExtMFD
END

 

[Notebook]

The international Cassini probe at Saturn will execute the course correction on Monday that will put it on a path to destruction.
The spacecraft is set to fly close to the giant moon Titan - an encounter that will bend its trajectory just enough to send it into the atmosphere of the ringed planet on Friday.

Its "Death Plunge" time! Not like Jonathan Amos to go over the top.

http://www.bbc.co.uk/news/science-environment-41222282

 

[Unstung]

The Planetary Society:
"What to expect during Cassini's final hours"
"And then there was one"

 

[Notebook]

http://www.esa.int/Our_Activities/S...uygens/How_to_follow_Cassini_s_end_of_mission

12 September 2017
The international Cassini mission reaches its dramatic finale this Friday by plunging into Saturn’s atmosphere, concluding 13-years of exploration around the ringed planet.
Here’s when to follow events broadcast by NASA via https://www.nasa.gov/nasalive this week (dates and times below are given in GMT/CEST; all times subject to change).

 

[Unstung]

BBC: "'Our Saturn years': Cassini's epic journey to the ringed planet, told by the people who helped make it happen"

[ame="https://youtu.be/DIE-cSGVYuI"]Cassini's Infrared Saturn[/ame]

JPL:
"Cassini Makes its 'Goodbye Kiss' Flyby of Titan"
"Cassini Spacecraft Makes Its Final Approach to Saturn"

Scientific American: "Cassini at Saturn: A Retrospective"

NPR: "Saturn's Strangest Sights, As Captured By A Doomed Spacecraft"

One day left.

 

[Notebook]

http://www.bbc.co.uk/news/resources/idt-sh/cassini_huygens_Saturn

Generic article about the mission, interesting bit about the NASA/ESA politics.

 

[GLS]

The unofficial Cassini mission end soundtrack, courtesy of the Emergency Medical Holographic program :rofl:

 

[Unstung]

There are five hours left until the expected loss of signal is received at Earth. Cassini is 83 light minutes away.

 

[GLS]

Cassini is now in its last hour...

 

[Urwumpe]

Again another bittersweet end of a long legendary mission - when Cassini-Huygens launched almost 20 years ago, I just left basic training at the army, after leaving school some months earlier.

Another mission over, that pretty much lasted for half of my life.

 

[Unstung]

As of this post, Cassini should be entering Saturn's atmosphere. The signal will take 83 minutes to arrive.

 

[Nicholas Kang]

Watch the live stream here for the arrival of the last signal here!

For 2D video (in case your device does not support 360 degree view), here is the NASA live broadcast:

 

[GLS]

Listening to something that doesn't exist... weird. :blink:

 

[IronRain]

Cassini EOM is called.

 

[Ravenous]

The semi-literate geek in me has just wondered:

1 - what mach number did Cassini enter at? (Not sure how to define a mach number in an atmosphere like that.)

2 - would anyone there "hear" a boom? (Possibly not, as I think the atmosphere even at breakup would have been incredibly thin.)

 

[jgrillo2002]

Cassini EOM is called.

EOM confirmed at 7:57:52 EST. O7 Cassini. and Thank you for all of your work, for humanity.

 

[Urwumpe]

1 - what mach number did Cassini enter at? (Not sure how to define a mach number in an atmosphere like that.)

You can define the speed of sound in ANY material. Even solids and plasma clouds.

2 - would anyone there "hear" a boom? (Possibly not, as I think the atmosphere even at breakup would have been incredibly thin.)

Lets also remark that its highly unlikely that a human will be near Saturn or near Saturn without a spacesuit. But a suitable microphone might at least hear the faint ultrasonic rumble after it disintegrated.

 

[Ravenous]

I googled for speed of sound at Saturn and found this which covers the four gas giants (the author acknowledges it isn't complete, but it is interesting anyway):

http://www.lpl.arizona.edu/~rlorenz/soundspeed.pdf

Figure 6 seems to imply a minimum of 600 m/s for Saturn, but that minimum is around 0.1 bar - and makes certain assumptions about the atmospheric composition. Urwumpe is right of course, there must be some equivalent speed of sound for any gas even a tenuous one.

Anyway it was just an idle thought

 

[IronRain]

Video, starting at T-2 minutes to EOM:

https://youtu.be/_dTYfFz5vII?t=14m38s

 

[cristiapi]

1 - what mach number did Cassini enter at? (Not sure how to define a mach number in an atmosphere like that.)

Here’s what I get from the JPL’s data file 170913BP_SCPSE_17224_17258.bsp located at
https://naif.jpl.nasa.gov/pub/naif/CASSINI/kernels/spk/

I don’t know the mach number, but the graph shows the speed wrt Saturn atmosphere.
The altitude is above the ellipsoid with equatorial radius = 60268 km and polar radius = 54364 km.