Spaceflight Now



Spaceflight Now +



Premium video content for our Spaceflight Now Plus subscribers.

Huygens science update
One week after the Huygens probe landed on Saturn's moon Titan, scientists hold a news conference to announce additional results and describe more pictures from the mission. (69min 02sec file)

 Play video:
   Dial-up | Broadband

ISS spacewalk preview
The upcoming spacewalk by the International Space Station's Expedition 10 crew is previewed by NASA officials at the Johnson Space Center on Jan. 21. (25min 04sec file)

 Play video:
   Dial-up | Broadband

Huygens mission science
After entering orbit around Saturn, the Cassini spacecraft will launch the European Huygens probe to make a parachute landing on the surface of the moon Titan. The scientific objectives of Huygens are explained by probe project manager Jean-Pierre Lebreton. (3min 14sec file)
 Play video

Saturn's moon Titan
Learn more about Saturn's moon Titan, which is believed to harbor a vast ocean, in this narrated movie. (4min 01sec file)
 Play video

Relive Cassini's launch
An Air Force Titan 4B rocket launches NASA's Cassini spacecraft at 4:43 a.m. October 15, 1997 from Cape Canaveral, Florida. (5min 15sec file)
 Play video

Deep Impact overview
Rick Grammier, NASA's Deep Impact project manager from the Jet Propulsion Laboratory, provides a detailed overview of the spacecraft and its mission. (4min 54sec file)
 Play video

Science preview
Deep Impact principal investigator Michael A'Hearn explains how the comet collision will occur and what scientists hope to learn. (7min 11sec file)
 Play video

Pre-flight news briefing
The pre-flight news conference is held at NASA Headquarters on December 14 to preview the Deep Impact mission to intercept a comet and blast a projectile into it. (54min 19sec file)
 Play video

Mars rover update
Steve Squyres of Cornell University, the rovers' principal investigator, discusses the latest discoveries from Spirit and Opportunity.
 Play video

Become a subscriber
More video



Titan forecast calls for rain, Huygens data shows
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: January 21, 2005

Liquid methane apparently falls like rain on Saturn's smog-shrouded moon Titan, washing down icy channels that ultimately spill into broad lakebeds dotted with ice islands and shoals, according to the latest data from Europe's Huygens probe. While the spacecraft did not detect any standing pools of liquefied natural gas in its immediate area, the data indicate rainfall is common on Titan and that liquid methane is present within a few inches of its surface.


This mosaic of three frames provides unprecedented detail of the high ridge area including the flow down into a major river channel from different sources. Credits: ESA/NASA/JPL/University of Arizona
Download larger image version here

 
"This isn't Mars, where the liquid that's done the erosion is buried underneath a solid," said Toby Owen, an interdisciplinary scientist with the Cassini-Huygens mission. "This is a planet where the liquids are right there. It might have rained yesterday. This is really a very active situation. That's the important news about detecting methane. It isn't that we think methane is there. It's really there in the liquid state."

Said Martin Tomasko, principal investigator with the Huygens descent imager instrument: "What we know is the place we landed is dry at the moment. But the liquid is not 200 meters underground, the liquid was within a few centimeters of the surface, indicating that it must have rained not very long ago. Does that mean yesterday or the day before, the week before? We don't really know. But the feeling is, in the place we landed, it must rain fairly frequently. But we can't be more precise than that."

NASA's Cassini Saturn orbiter released the Huygens probe on Christmas Eve. The small spacecraft, built by the European Space Agency, slammed into Titan's thick nitrogen atmosphere Jan. 14 and descended by parachute to the moon's frozen surface, snapping pictures and sampling the atmosphere as it fell.

Hitting the surface at about 11 mph, Huygens broke through a thin crust-like material and settled several inches into a spongy hydrocarbon "soil" with the consistency of loose sand. Nearby chunks of dirty water ice show clear signs of fluid erosion, indicating the spacecraft landed in a zone that at least occasionally experiences flowing liquids.

At a news conference early today to unveil the latest data from Huygens, Owen said pre-landing predictions that liquid methane should exist on the surface of the ultra-cold world - minus 290 degrees Fahrenheit at the surface - were pretty much correct.

"What we've learned is that our speculation is really pretty good," Owen said. "The main difference, the main new thing that we have is that indeed, we can detect liquid methane on the surface. It's not seas of liquid ethane, it's really liquid methane, liquid natural gas."


A view of Titan from the VIMS instrument on the Cassini orbiter. The Huygens probe landed in the small red circle on the boundary of the bright and dark regions. The size of the circle shows the field of view of the Huygens DISR imager from an altitude of 20 kilometres. Credits: ESA/NASA/JPL/University of Arizona
Download larger image version here

 
Tomasko provided a fresh interpretation of a picture released last week showing what appeared to be channels in elevated terrain bordered by an apparent shoreline.

Stereo images show a ridge system in the image is more than 300 feet above the surrounding terrain. Dark channels can be seen in the light-colored elevated terrain leading to larger river bed-like features that empty into a basin.

After studying the images for a week, Tomasko said his team believes the channels "really are evidence of rain."

"These branching, dendritic channels are evidence of rain and the dark material in the bottoms of the channels is very likely this photochemical smog that falls out of the atmosphere, coats the whole terrain and gets preferentially washed off the top of the ridges," he said.

"The top of the ridges are ... not really very bright, they're relatively dark, but the dark material is definitely concentrated in the bottom of these drainage channels. And these ridges, we think, are made not of silicate rocks as on the Earth, but frozen, hard water ice. So we think we're seeing water ice ridges washed off by rainfall with a liquid and a concentration of these organic materials in the bottom of the (channels)."

Looking at a larger mosaic that included the original picture, Tomasko said "we see this river system which flows down into this delta, into this low-lying terrain. We see this ridge draining from the back and these dendritic structures and then coming down from the front draining also into this broad, low-lying terrain."

In a new picture released today, Tomasko described additional features that indicate flowing liquids, including short, stubby channels that could indicate methane springs and areas that might be extrusions of water ice. Another photo showed a thin ridge in one of the pool-like basins that had multiple channels cut through it, presumably from erosion, giving the appearance of a chain of islands.


A single image from the Huygens DISR instrument of a dark plain area on Titan, seen during descent to the landing site, that indicates flow around bright 'islands'. The areas below and above the bright islands may be at different elevations. Credits: ESA/NASA/JPL/University of Arizona
 
"So there's lots of evidence of fluid flow, there's lots of evidence of this dark material, there's some evidence of water ice extrusion as well," Tomasko said. "We don't think we see liquids in these areas, but we do think there's plenty of evidence that there was flowing fluids on the surface of Titan."

For methane be present in the atmosphere today, it must be constantly replenished. Owen said the source of the methane was Titan itself.

"The photochemistry is happening up above, breaking methane apart, fragments are combining, making more complex things, making these smog particles and they're precipitating down to the surface," he said. "The methane, as we expected from the beginning, must condense because it's so cold on the surface of Titan that we would expect liquid natural gas to be present there. And now the question is, is it really there?"

Data from Huygens shows nitrogen is the dominant gas in the upper atmosphere of Titan. But as the probe descended, methane concentrations shot up.

"This is just like what happens on the Earth with water vapor," Owen said. "Water on Earth is confined to the lower atmosphere. ... The reason is, there's a very low temperature point in the atmosphere and there's the same thing on Titan, there's a kind of cold trap that forces the methane to be down below so that the methane increases more rapidly than the nitrogen as you go down into the lower atmosphere. That's where it is.

"Now, when you come to the surface, you would expect everything to be stable and that's what the nitrogen indeed does. ... However, the methane suddenly jumps up by about 30 percent. Boom, in three minutes, up it goes. That methane must be coming out of the ground and that's the exciting part. It means there's liquid methane very near the surface, maybe right on the surface."

Tomasko said it's possible Huygens landed in Titan's equivalent of an arid region on Earth.

"We don't think we have open pools of liquid methane, but the methane kind of sinks down into the surface material," he said. "It's more like Arizona or someplace like that where the river beds are dry most of the time but after rain, you might have open flowing liquids and pools. These pools gradually dry out, the liquid sinks down into the surface. Perhaps it's very seasonal."

No one yet knows. But Jean-Pierre Lebreton, the Huygens mission scientist for the European Space Agency, said Titan would make an ideal target for some future robot lander.

Spaceflight Now Plus
Video coverage for subscribers only:
VIDEO: FRIDAY'S PHOTO & SCIENCE BRIEFING DIAL-UP | BROADBAND

VIDEO: PICTURES PRESENTED WITH EXPERT NARRATION QT
VIDEO: LISTEN TO SOUNDS FROM HUYGENS WITH NARRATION QT
AUDIO: LISTEN TO SOUNDS FROM HUYGENS WITH NARRATION FOR IPOD
VIDEO: RESULTS FROM HUYGENS' SURFACE SCIENCE PACKAGE QT
VIDEO: CHIEF SCIENTIST EXPLAINS COMMUNICATIONS ERROR QT
VIDEO: SATURDAY PHOTO & SCIENCE BRIEFING DIAL-UP | BROADBAND
AUDIO: SATURDAY PHOTO & SCIENCE BRIEFING FOR IPOD

VIDEO: THE FIRST PICTURE FROM HUYGENS IS REVEALED QT
VIDEO: HUYGENS POST-LANDING NEWS BRIEFING DIAL-UP
VIDEO: STATUS REPORT DURING DESCENT DIAL-UP | BROADBAND
AUDIO: MISSION STATUS REPORT DURING DESCENT FOR IPOD
VIDEO: HUYGENS PRE-ARRIVAL NEWS BRIEFING DIAL-UP | BROADBAND
AUDIO: HUYGENS PRE-ARRIVAL NEWS BRIEFING FOR IPOD

VIDEO: OVERVIEW OF HUYGENS PROBE'S SCIENCE OBJECTIVES QT
VIDEO: JULY NEWS BRIEFING ON CASSINI'S PICTURES OF TITAN QT
VIDEO: PICTURES SHOWING TITAN SURFACE FROM OCT. FLYBY QT
VIDEO: WHAT'S KNOWN ABOUT TITAN BEFORE THE FIRST FLYBY QT
VIDEO: NARRATED MOVIE OF CLOUDS MOVING NEAR SOUTH POLE QT
VIDEO: OCT. BRIEFING ON RADAR IMAGES OF TITAN SURFACE QT
SUBSCRIBE NOW

Ares 1-X Patch
The official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.
 U.S. STORE
 WORLDWIDE STORE

Apollo Collage
This beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.
 U.S. STORE

Expedition 21
The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.
 U.S. STORE
 WORLDWIDE STORE

Hubble Patch
The official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase.
 U.S. STORE
 WORLDWIDE STORE

INDEX | PLUS | NEWS ARCHIVE | LAUNCH SCHEDULE
ASTRONOMY NOW | STORE

ADVERTISE

© 2014 Spaceflight Now Inc.