Cassini Tunes In to Radio Titan!

NASA / JPL / Val Klavans
NASA / JPL / Val Klavans

UPDATE: THE IMAGES ARE IN! Click here to see them.

Q U I C K   F A C T S

  • Date : May 16, 2014 (6:12 PM UTC) – May 18, 2014 (3:12 PM UTC)
  • Time of Closest Approach : May 17, 2014 @ 4:12 PM UTC
    (What time Cassini is closest to Titan)
  • Altitude at Closest Approach : 1,860 miles (2,994 kilometers)
  • Speed : 13,000 mph (5.8 km/sec)
  • Goal : To learn more about Titan’s surface


* * *


F l y b y   b e g i n s
(Inbound part of the flyby)

On Cassini’s way to Titan, its camera system, also known as the Imaging Science Subsystem (ISS) instrument, will observe Titan’s southern hemisphere. ISS will also acquire a global mapping mosaic of Titan. It will cover much of the visible face of Titan and will be centered just south of eastern Aztlan.

Below is a simulated view from Celestia of ISS’ global mapping mosaic of Titan.

Celestia / Ian Regan
Celestia / Ian Regan

Cassini’s Composite Infrared Spectrometer (CIRS) instrument will measure Titan’s atmospheric and surface temperatures. CIRS will also make observations focusing on the surface and limb of the moon.

 The Ultraviolet Imaging Spectrometer (UVIS) instrument onboard Cassini will observe Titan as it passes in front of the star Eta Ursae Majoris. (This type of astronomical event is called a stellar occultation.) This stellar occultation will provide high-resolution profiles of the hydrocarbons, haze, temperature and pressure in Titan’s atmosphere. UVIS can probe deep into Titan atmosphere — down to an altitude of 200 kilometers (124 miles) — well below the minimum altitude Cassini can safely approach Titan.

On Earth, we view Eta Ursae Majoris (also known as Alkaid) as the easternmost star in the “Big Dipper” constellation. Click on the image below to learn more.

© Jerry Lodriguss
© Jerry Lodriguss

Below is a simulated view from Celestia of Eta Ursae Majoris passing behind Titan.

Celestia / Ian Regan / Val Klavans

ISS will be riding along during CIRS’ and UVIS’ observations and taking photos along the way.

C l o s e s t   a p p r o a c h
After closest approach, Cassini begins to travel away from Titan (outbound part of the flyby).

The overall goal of this flyby is to learn more about Titan’s surface. In order to accomplish this, Cassini’s Radio Science Subsystem (RSS) instrument will bounce radio signals off Titan’s surface which will be received on Earth (also known as a bistatic observation). This experiment will yield important information about the composition, reflectivity, and roughness of Titan’s surface.

At closest approach, when Cassini is closest to Titan during the flyby, RSS will send a signal through Titan’s atmosphere that will then be acquired back on Earth (also known as a radio occultation). From this experiment we can learn more about  wind, temperature, and variations due to seasonal change in Titan’s atmosphere.

To see how Cassini carries out the radio occultation, check out the video below.

NASA / JPL / Cassini Scientist For a Day

O u t b o u n d

As Cassini leaves Titan, ISS will observe a crescent Titan over its northern hemisphere.

RSS will also acquire a bistatic observation of Ligeia Mare and Kraken Mare (Titan’s second and first largest seas, respectively).

Below is a recent radar view of Titan’s largest seas, located near its north pole.

NASA / JPL / ASI / USGS / Val Klavans
NASA / JPL / ASI / USGS / Val Klavans

CIRS and UVIS will acquire more data about the structure, temperature, and composition of Titan’s upper haze layers. ISS will be riding along again, snapping more photos along the way.

E n d   o f   f l y b y

* * *


Cassini’s ISS snapped many views of Titan in different wavelengths — to see above and below its atmosphere. In this view, on the top is a true color image of Titan and below is a view of its surface. ISS used its infrared filter to peer through Titan’s atmosphere and image its surface. Kraken Mare is visible in this view. Click on the image for more details.

NASA / JPL / SSI / Val Klavans
NASA / JPL / SSI / Val Klavans

This is a true color view of Titan’s haze layers from the ISS. Click on the image to learn more.

NASA / JPL / SSI / Val Klavans
NASA / JPL / SSI / Val Klavans

Titan’s Surface Revealed

The ISS captured views of Titan’s surface in greater detail than in the past few flybys. Click on the image below to see an un-labeled version.

NASA / JPL / SSI / Ian Regan / Val Klavans
NASA / JPL / SSI / Ian Regan / Val Klavans

One day after the flyby, Cassini’s ISS also saw Titan’s many lakes and seas from a distance of 442,490 miles (712,119 kilometers) away. Click on the image below for an un-labeled version.

NASA / JPL / SSI / Val Klavans
NASA / JPL / SSI / Val Klavans

Check out more images from the flyby right on my Facebook event page.

 * * *


Want to know even more about this flyby? Check out Cassini Imaging Central Laboratory for Operations’ (CICLOPS) website with information on Cassini’s activities every day: Rev204: Apr 27 – May 31 ’14 and a quick overview of this flyby from Cassini’s main website: Titan Flyby (T-101): Radio Science Focus. (All of my information from this post, unless otherwise specified, comes from these sources.)


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