Help Shape the Future of Space Exploration

Join The Planetary Society Now  arrow.png

Join our eNewsletter for updates & action alerts

    Please leave this field empty
Blogs
Facebook Twitter Email RSS AddThis

Bill Dunford profile thumbnail

A Map of the Evening Star

Posted By Bill Dunford

20-08-2013 1:27 CDT

Topics: pretty pictures, amateur image processing, radar imaging, Venus, Venus missions before 2000, mapping, naming things

“A map says to you, Read me carefully, follow me closely, doubt me not. I am the Earth in the palm of your hand.”

—Beryl Markham

Beryl Markham knew about maps. She was a pilot, author and racehorse trainer, most famous for being the first woman to fly alone across the Atlantic from east to west, an adventure she recounted in her memoir, West with the Night. As an aviator, she would have been very familiar with the sight of the evening and morning starthe planet Venusin the sky.

What she didn't know was that just a few years after her death, a robotic spacecraft would circle Venus, fire powerful bursts of radar through its veil of clouds, and begin to image the strange world's oven-hot surface. Those radar images would allow a new breed of explorer to make a new generation of maps, including one chart in particular that marks the location of a crater named Markham.

I like maps of the planets beyond Earth. They're both informative and beautiful. They embody craftsmanship, precision, and art. The US Geological Survey actually produces wall-sized paper maps of nearly every body in the Solar System. I love how these maps allow a mental line to be drawn: from a 17th-century sea captain poring over charts in his cabin as he explores new coastlines, all the way to a 21st-century post-doctoral student in front of a computer monitor, discussing potential landing sites on Europa with her peers on multiple continents in real time.

Take as an example one map in particular, a geological map of the Diana Chasma quadrangle of Venus. Before the space age, the planet Venus was a blank sphere, continuously shrouded in thick layers of clouds. (Many people assumed this meant the planet was covered in steamy jungle. You probably know the reality is starker: the clouds created a runaway greenhouse effect that rendered the surface the hottest in the Solar System, a hell of acidic skies and temperatures in excess of 460 degrees celsius.)

Even to most passing spacecraft, the view of Venus is nothing but cloud tops.

Venus by Galileo

NASA / JPL / Bill Dunford

Venus by Galileo
Venus as seen by the Galileo spacecraft as it swung by the planet for a gravitational boost on its way to Jupiter in 1990. The image has been processed to increase contrast and remove minor artifacts. The color is added.

Several Soviet craft dared a landing. They only survived a few minutes. The key to piercing the veil of Venus planet-wide turns out to be radar. Scientists learned a lot using facilities like the giant antenna at the Arecibo Observatory to bounce radar signals through the clouds, off the surface, and back to Earth for analysis.

Even better, in the 1990s an orbiter named Magellan took up its station at the second planet. It carried a synthetic aperture radar system to map the surface. Radar imaging and altimetric and radiometric mapping covered 98 percent of the planet, with radar resolution of about 120 meters. This allowed Magellan to create lovely images of the landscape, like this one of the area surrounding Markham Crater. Venus explorers think a violent impact dug the crater, and either melted or released molten rock that flowed downhill.

Markham Crater and Surroundings

NASA / JPL

Markham Crater and Surroundings
Markham Crater on Venus, as imaged via radar by the Magellan spacecraft. Markham is the round crater with the light-colored outflow at the upper right. Scientists interpret the feature as impact melt or fluidized ejecta created by meteorite impact. The crater is about 75km across.

In this view, we can see some of the planet's extremes. There are tall raised areas like Miralaidji Corona, which is an example of where hot magma welled up near the surface, creating radial fractures and causing lava to spill out across the plains. But in this same shot we can see part of Diana Chasma, a 900-kilometer-long trough that includes some of the deepest points on the globe. This is among the steepest terrain on Venus, with altitudes ranging from –2.5 to 4.7 km. In some places the slopes incline more than 30 degrees.

Miralaidji Corona and Diana Chasma

NASA / JPL

Miralaidji Corona and Diana Chasma
Magellan radar view of two landforms on Venus: Miralaidji Corona (feature at upper right with radiating fractures) and part of Diana Chasma (horizontal structure to the left of Miralaidji). Coronas result from rising bodies of magma that generate volcanic flows and fault patterns. Diana Chasma is one of the deepest points on the planet.

All this exploration yields more than pretty pictures. By analyzing data from the full suite of instruments on board Magellan, along with information from other orbiters, landers, and Earth-bound observers, scientists can begin to piece together the geologyand thus the historyof Venus as a whole. All without risking boots (smoking, melted boots) on the ground.

One product of the data collection and painstaking analysis is this gorgeous map of the Diana Quadrangle, including Markham Crater and Miralaidji Corona, along with many other craters, cliffs, and fissures.

Map of the Diana Chasma Quadrangle of Venus

USGS / Vicki L. Hansen and Heather R. DeShon

Map of the Diana Chasma Quadrangle of Venus
A map of the Diana Chasma quadrangle, an equatorial region of Venus between 0º to 25º S. and 150º to 180º E. that encompasses about 8.4 million square kilometers. It's home to several large coronae and especially deep trenches, including its namesake.

You can see more detail by clicking the image, or get the complete map, key, and other notes on the USGS site.

There is still so much to explore, so many places where the maps are incomplete. Pioneering aviator Beryl Markham wrote that, "I learned to wander. I learned what every dreaming child needs to knowthat no horizon is so far that you cannot get above it or beyond it."

But none of this will be easy. She also warned, “We fly, but we have not 'conquered' the air. Nature presides in all her dignity, permitting us the study and the use of such of her forces as we may understand. It is when we presume to intimacy, having been granted only tolerance, that the harsh stick falls across our impudent knuckles and we rub the pain, staring upward, startled by our ignorance.”

 
See other posts from August 2013

 

Read more blog entries about: pretty pictures, amateur image processing, radar imaging, Venus, Venus missions before 2000, mapping, naming things

Comments:

Tony Mach: 08/20/2013 06:49 CDT

I am afraid your view to Venus is a bit US-centric… The Venera probes (yes, they had a name), send by the Soviet Union (and not Russia) did not survive for a "few" minutes, but actually some survived for about two hours, at a designed life of about an half hour. Saying that the Venera probes survived only a "few minutes" is akin to saying that MER Spirit survived only a "few weeks". Technically correct but highly misleading. And while I understand that your topic are these beautiful USGS maps, and your point about the Venera probes was possibly that accessing the surface of Venus is damn hard, there are actually images of Venus' surface send by the Veneras – in one case even beautiful color images, which have been recently resorted with modern technology, if I am not mistaken. I know material produced by the USGS, NASA or other such agencies in the USA is much easier to come by than products of a secretive and long gone state, but being ignorant of Soviet space flight and space exploration means ignoring a (considerable) part of Solar System exploration – it is a loss for the PS and anybody interested in Solar System exploration to do so.

Bill Dunford: 08/20/2013 08:23 CDT

Thank you, Tony. You're exactly right: my point about Venera was simply that "damn hard" is an understatement when it comes to keeping surface landers functioning for an extended period of time in order to carry out long-term exploration. I didn't mean any slight whatsoever to the Soviet program. Here are a couple of examples of Venus surface panoramas: http://www.planetary.org/multimedia/space-images/venus/20120907_venera_9_panorama_stryk.html and http://www.planetary.org/multimedia/space-images/venus/venera_10_panorama_stryk.html And readers may be interested in this important moment in Soviet robotic exploration: http://www.planetary.org/blogs/guest-blogs/bill-dunford/20130429-dark-no-more-exploring-the.html

Bob Ware: 08/20/2013 12:53 CDT

Historical Note: The Soviet Union and the U.S. were not on speaking terms for a while, encompassing NASA also, thus TPS being an international body the CCCP (USSR), released some Venera photos to the public via us and The Planetary Report (TPR). Some past Venus reports in TPR are: Vol II, #6 - Nov/Dec 1982, Vol IX, #5 - Sep/Oct 1989, Vol XIII, #3 - May/Jun 1993, Vol XIV, #2 - Mar/Apr 1994 and the Dec. Solstice 2011. More Venera data is on http://mentallandscape.com (/V_Venus.htm). A side note in Vol II, #6. A Mariner Project Manager, Marcia Neugebauer, led the Mariner Mark II development which became known as Voyager (3 S/C of which only 2 flew, #'s 2 & 3).

Bill Dunford: 08/20/2013 01:02 CDT

Excellent. Thanks, Bob.

Anonymous: 08/21/2013 11:40 CDT

Few tidbits and corrections: Mariner Mark II was not Voyager. Mariner Mark II came after Voyager, evolved into Cassini. During period US and USA "not on speaking terms" Soviet scientists worked with USGS scientists, prepared published map of Venus n. pole based on Venera 15/16 radar data in prep for Magellan. Soviet robotic spacecraft have in general had little of the success of US and ESA spacecraft; can't really compare Sov/Russian accomplishments, if you want to be intellectually honest, not just politically correct. That said, the Lunokhods are among by fave robo missions ever. dsfp http://www.wired.com/wiredscience/beyondapollo/

David S. F. Portree: 08/21/2013 11:43 CDT

Reposted with "nickname" and small correction. A few tidbits and corrections: Mariner Mark II was not Voyager. Mariner Mark II came after Voyager, evolved into Cassini. During period USSR and USA "not on speaking terms" Soviet scientists worked with USGS scientists, prepared USGS published map of Venus n. pole based on Venera 15/16 radar data in prep for Magellan. Soviet robotic spacecraft have in general had little of the success of US and ESA spacecraft; Sov/Russian accomplishments on nowhere near same par, if you want to be intellectually honest, not just politically correct. That said, the Lunokhods are among my fave robo missions ever. dsfp http://www.wired.com/wiredscience/beyondapollo/

Bob Ware: 08/21/2013 09:59 CDT

Hi Anonymous & David P. -- Thanks guys. A memory slip up on my part. Great catch & thanks! I was not aware of the USGS being able to work with the USSR at that time frame. Others: here is what they caught regarding my Mariner error: http://history.nasa.gov/computers/Ch6-2.html NASA funded, a project called Mariner-Jupiter-Saturn 1977. It was given the name [174] Voyager in the mid-1970s.. ==== http://space.jpl.nasa.gov/msl/Programs/mariner.html “…The planned Mariner 11 and 12 vehicles evolved into Voyager 1 and 2. A set of missions planned as follow-ons to the Mariner series, Mariner Mark 2, was cancelled in the early '90s due to budgetary constraints. …” Also: from the same link: “…The CRAF mission uses the first of a new series of RTG-powered three-axis stabilized planetary spacecraft, the Mariner Mark II, ... Curator: E. Bell, II; .”

Leave a Comment:

You must be logged in to submit a comment. Log in now.

Fly to an Asteroid!

Travel to Bennu on the OSIRIS-REx spacecraft!

Send your name

Join the New Millennium Committee

Let’s invent the future together!

Become a Member

Connect With Us

Facebook! Twitter! Google+ and more…
Continue the conversation with our online community!