The Seasteading Institute, Paul Spooner - Concept Art

During a presidential election year in the United States and amid a troubling global economic situation, escape is probably in the back of many peoples’ minds.  Why not escape then to the sea, where your home might one day be mobile enough to set sail for a makeshift water nation tailored to your own beliefs?

Seasteading - creating “permanent dwellings on the ocean” - is an idea that has found recent financial backing and media attention.  Those interested in seasteading hope it will take off in the same way that the private space industry has taken off in recent years.

The Seasteading ‘08 Conference will be held on October 10, 2008 in Burlingame, CA, USA.  The day of workshops will focus on the first steps required to reside on the ocean, including business plans, governance issues, and designs.

steins_-_the_movie_v3 [AVI video]

Credits: ESA ©2008 MPS for OSIRIS Team MPS/UPM/LAM/IAA/RSSD/INTA/UPM/DASP/IDA - “An animation of the closest approach of Rosetta to asteroid Steins“. AVI format, 3014 kb.

Along with first images, anaglyphs and initial data results from Rosetta’s successful flyby of Asteroid (2867) Šteins, mission team members put together an animation of the flyby.

More Information

• Rosetta
  • Rosetta Blog
  • Press Release: “Steins: A diamond in the sky“

Related Books

Hours after its successful flyby of “the jewel of the solar system”, the robotic traveler Rosetta continues to return data from the encounter. From a point of light discovered in 1969 into a world of new vistas, here is Asteroid (2867) Šteins:

Credits: ESA ©2008 MPS for OSIRIS Team MPS/UPM/LAM/IAA/RSSD/INTA/UPM/DASP/IDA - Cutout of “Asteroid Steins seen from a distance of 800 km“

At a press conference to announce preliminary results and to show the first images of Šteins, European Space Agency (ESA) scientists compared the shape of the asteroid to that of a jewel and a diamond. The predicted shape model based on data obtained from Earth-based telescopes held up during the encounter, but the asteroid turned out to be nearly 10% bigger than expected. At its largest diameter Šteins measures 5.9 kilometers,

Credit: ESA TV - “Rosetta spacecraft meets asteroid Steins“

Rosetta, the European Space Agency (ESA) spacecraft on its way to orbit and deploy a lander on a comet, is now approaching Asteroid (2867) Šteins. The flyby will bring the spacecraft within 800 km of Šteins on Friday evening, September 5, 2008. The ESA will provide a webcast about the event beginning on September 06, 2008 from 04:00 until 11:20 GMT on the Rosetta website. Data is expect on Saturday after the flyby has been completed.

Šteins is 4.6 km in diameter and located in the main asteroid belt. Rosetta will collect information about the asteroid as it speeds by on its way to Comet 67P/Churyumov-Gerasimenko.

Here is the Šteins flyby timeline provided by ESA on the Rosetta Blog:

Venus is the Earth-that-could-have-been and the Earth-that-still-might-be.  Our so called sister planet orbits second from the Sun. Cloudy, hot, and unhospitable to life as we know it, Venus demonstrates as well as Mars why comparative planetary science can greatly improve understanding of our own planet.

The greenhouse effect on Venus results in a poorly understood phenomena called zonal super-rotation. Hurricane winds across the cloud tops help the atmosphere to rotate much faster than the planet itself, but these winds give way to barely a breeze at the surface. The atmosphere is primarily carbon dioxide with some nitrogen. Thick sulfur dioxide clouds and other particulates conspire to hide the surface. The USSR visited the surface of Venus with several landers, some that included cameras, while orbiters with radar equipment accomplished global surface mapping last decade by orbiters. Mountains, volcanoes, pancake domes, plains, channels, and a impact craters have been discovered on the surface. The surface appears to be geologically young, despite little evidence for plate tectonics, the process on the Earth that recycles old crust and exudes new crust. The youthfulness of the Venusian surface may be due to catastrophic upheavals that periodically see the crust overturned (this might have last occurred from 300 to 500 million years ago).

I will be speaking at the Sunday, September 7 meeting of the Humanist Society of Greater Phoenix about “Images of Mars and Interplanetary Science.” This series of posts in preparation for the event will explore current spacecraft activities in planetary science.

After the astronomy revolt that left the solar system with eight planets, four dwarf planets, and a huge variety of other celestial objects, Mercury became the smallest planet.  Despite its newfound stature, Mercury remains an important destination for better understanding the inner and rocky solar system.  It also remains little explored, a state that has only recently been addressed by a new spacecraft with a comprehensive suite of instruments.

Credit: NSSDC Photo Gallery: Mercury - “Mercury Mosaic #1” taken by Mariner 10

Mercury can be difficult to see from the Earth despite being one of the brightest objects in the night sky.  The planet orbits close to the Sun, which also makes it a difficult destination to reach for spacecraft.  In fact, until recently only one spacecraft had visited Mercury.  In 1974 and 1975, Mariner 10 explored Mercury during three flybys.  Due to the geometry of the encounters, Mariner 10 was only able to image approximiately 45% of the planet’s surface.  The rest of the planet has been mapped at low resolution using Earth-based radar.

33 years later, MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) has finally provided the first close up images of surface features unexplored by Mariner 10.  The first flyby of the MESSENGER mission occurred on January 14, 2008.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington - “Mercury Shows Its True Colors” taken by MESSENGER

MESSENGER returns to Mercury for another pass on October 6, 2008 and again on September 29, 2009. However, on March 18, 2011 the mission gets especially interesting; the spacecraft will fire its thrusters to slip into orbit around Mercury. Although nearly all of the planet will have been mapped by this time, the closer proximity will allow a year-long study of the environment in which Mercury orbits the Sun and its tenuous atmosphere, as well as inspection of its geology and composition. Mercury hosts particularly interesting landmarks like the enormous Caloris impact basin and polar craters that may be shadowed enough to trap water in the form of ice despite the planet’s proximity so close to the Sun.

Mercury apparently has a massive iron core as a result of formation in the inner solar system and possibly due to a traumatic collision with another body that skinned the developing planet soon after differentiation. MESSENGER has spotted good evidence for volcanism to explain Mercury’s smooth lava plains, though it is likely that such activity occurred early in the planet’s history. Extensive systems of faults, ridges and cliffs as well as a spider-like formation of fractures within Caloris Basin show that Mercury has had a complex geological history.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington - “‘The Spider’ - Radial Troughs within Caloris” taken by MESSENGER

This history, among other data, may provide further information related to the formation of Mercury, the rocky inner planets, and the Solar System as a whole. Our Solar System is striking for the rocky composition of its inner planets and the gaseous and icy nature of its outer planets. Mercury is on the extreme end of this spectrum of planetary composition dictated by nearness to the developing Sun. Just how “dry” is Mercury? Why is the planet so dense? These questions and more can finally be addressed by the renewed exploration of the innermost planet. The next few years promise a wealth of discovery for scientists who have long clamored for a return visit to Mercury and finally saw their dreams realized after the turn of the century, and should help to keep feeding the public’s interest in planetary science and exploration.

More Information

• Mariner 10
• MESSENGER
• Previous Coverage of Mercury on Frontier Channel

Related Books

“Planetary Provenance” Posts

• Mercury
• Venus

One of many new Cassini images received after yesterday’s successful Enceladus flyby. Image Credit: NASA/JPL/Space Science Institute - “W00043237.jpg“

Slow server speeds mark the arrival of new raw data on the Cassini-Huygens website taken during yesterday’s successful Enceladus flyby. In addition to the images, Cassini sampled the material in Enceladus’ water ice plumes erupting from the moon’s south pole. Images like the one above will be validated and calibrated while scientists pour over all the new data, hoping for insight into the process that leads to the geyser-like features.

Cassini took this image of Enceladus’ water ice plumes on November 27, 2005.  New pictures and other data from the most recent flyby on Wednesday, March 12, 2008 are expected on Thursday, March 13, 2008.  Image Credit: NASA/JPL/Space Science Institute - “Jet Blue“

NASA’s Cassini spacecraft has successfully completed the closest flyby of Saturn’s mysterious moon Enceladus yet. Coming as close as 52 kilometers (32.3 miles) from the surface of Enceladus, Cassini used its array of instruments to sample the water ice geysers that erupt from the moon’s south pole. The close, and somewhat risky, flyby maybe provide just the required data to begin understanding the source of these geysers. These data have started to arrive at the Earth and will be completely downloaded over the next several hours.

On Wednesday, March 12, 2008 around noon PST, Cassini flew away from Enceladus along the outer extent of the plume that surprised scientists just over two years ago. The surprise was due to the moon’s small size; small moons were generally thought to be inactive, as no internal forces would be present to drive any surface activities. Whatever is driving the spectacular activity on Enceladus remains a mystery.

Recently, two sources for the geysers have been proposed. The “dry” theory suggests that tidal forces along the “Tiger Stripes” fractures discovered at the moon’s south pole rub ice until it is heated sufficiently to escape. The “wet” theory suggest that these tidal forces instead heat a spot in the moon’s interior, resulting in enough heat to melt a lake or ocean of liquid water just below the surface. This pressurized water then escapes through the discovered fractures.

The latest flyby is intended to sample the geysers to determine which of these theories might be correct, or suggest alternative theories. An underground reservoir of liquid water and the forces required might create a potentially habitable location and an intriguing site to look for life. Cassini will look for the presence of sodium, among other elements and compounds, to support the “wet” theory.

Cassini is nearing the completion of its nominal four-year mission to explore Saturn, its rings, and its moons. The mission has been extended for two more years, allowing mission planners to take more risks. Scientists believe that the ice and other particles in the geyser are tiny enough to pose no harm to Cassini. If confirmed, this will allow scientists to fly Cassini closer yet in upcoming explorations of Enceladus. Raw data could start appearing on the Cassini website as early as 5:00 AM PST on Thursday and mission scientists hope to have a preliminary analysis of data completed by Thursday afternoon.

More Information

• Cassini-Huygens Website
  • Saturn’s Moons section
  • Enceladus Information
  • Press Release (NASA/JPL): “Cassini Spacecraft to Dive Into Water Plume of Saturn Moon“
  • Blog: Visiting Enceladus

Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington - “MESSENGER’s First Look at Mercury’s Previously Unseen Side“

A heavily cratered side of the planet Mercury never before seen has been revealed by the Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) spacecraft. A single image was released by NASA this evening after the successful flyby of the innermost planet on Monday. Featuring rayed craters, a portion of one of the largest basins in the solar systems, and rings of dark material, the new image is one of over 2000 captured during the first flyby of Mercury in thirty-three years.

More data is expected to arrive on the Earth on Wednesday after MESSENGER’s scheduled contact over the Deep Space Network was postponed due to unexpected problems with other missions and a shift in priorities.  In addition to the global wide-angle image released this evening,  these data include approach and departure images that will be turned into movies and high resolution narrow-angle images taken from only 200 kilometers above Mercury’s surface during closest approach.

In 1975 Mariner 10 successfully completed its third and final flyby of Mercury after imaging less than 50 percent of the planet’s surface.  MESSENGER will complete this mapping task between yesterday’s flyby and two more flybys scheduled for October 06, 2008 and September 29, 2009.  Then, on March 18, 2011, MESSENGER will enter orbit around Mercury for a planned year-long science phase.

The data returned by MESSENGER are expected to answer several longstanding questions about Mercury.  MESSENGER will use its array of instruments protected by a sunshade to search for evidence of water ice trapped in deep and dark craters at the planet’s poles, a potentially counter intuitive finding given Mercury’s close proximity to the Sun.   Scientists will study the planet’s surface and composition as well as its inner structure.  Mercury has a dense core of iron thought to compose a more significant portion of the planet than the cores of the other inner planets do.  Why this should be the case is complicated by the presence of a magnetic field around Mercury.  Magnetic fields are thought to depend on molten cores, but models of Mercury indicate that due to its small size its core should have solidified by now.

More Information

• MESSENGER Website
  • Press Release and Image: “MESSENGER’s First Look at Mercury’s Previously Unseen Side“

Image Credit: NASA - “Plentiful Planetary System” - “This artist’s concept shows four of the five planets that orbit 55 Cancri, a star much like our own.”

NASA announced during a press telecon this morning the discovery of a fifth planet in the 55 Cancri system. This sets a new record for exoplanets in a single system and might indicate that multi-planet systems like our own are common in the Milky Way.

The discovery brings to five the number of planets detected in this system since the first was discovered over a decade ago. The technique used was the “wobble” method, also known as the radial velocity technique. Planets tug on their parent stars, and this tug will show up as a doppler shift of the star as viewed from the Earth. Plotting these shifts over a period of 18 years and taking advantage of technological progress for both hardware and software, scientists collected the necessary data to indicate the presence of this planet. The newly detected planet orbits 55 Cancri, located approximately 41 light years away in the constellation Cancer, near Orion. The planet is located 0.78 AU away from 55 Cancri, about the distance of Venus from the Sun in our own system.

This location appears to be within the star’s habitable zone, a theoretical location around stars where temperate temperatures may allow liquid water to puddle on planetary surfaces. The new planet is 45 times the mass of the Earth, suggesting it is an ice or gas giant, but any moon located around the planet could be interesting places to search for liquid water, and life. Debra Fischer, astronomer from San Francisco State University, stated that the 55 Cancri system is packed with planets, like our own system. Technology trends along with steady funding support from NASA and the NSF allowed Earth-based telescopes to increase in capability enough to pull about the separate tugs of the five planets in the 55 Cancri system. New imaging technologies could lead to the discovery of the first Earth-sized planet within 15 to 20 years, according to Jonathan Lunine, a planetary scientist at the University of Arizona.

Geoff Marcy, an astronomer at the University of California, Berkeley, said the discovery “has me jumping out of my socks.” To date, most exoplanets discovered have been single members of their parent stars. The 55 Cancri system might indicate that the Milky Way is full of billions of planetary systems and increases the possibility of Earth-like planets. Marcy highlighted the structure of the new system, reminiscent of our own system. Four of the planets, including the newly discovered planet, occupy the inner system while there is a large gap between .78 AU and 5.9 AU in the 55 Cancri system. A planet many times more massive than Jupiter exists at the other end of this gap. It is currently not known whether other planets might be located within this gap, or if the larger planet is sufficiently massive to prevent planet formation in the gap.

Lunine waxed philosophically about the discovery. He quoted St. Albertus Magnus who asked approximately 760 years ago: “Do there exist many worlds, or is there but a single world? This is one of the most noble and exalted questions in the study of Nature.” It took over 7.5 centuries to answer his question, with the first detection of a planet outside of our own solar system, but only now are systems of planets similar to our own being discovered. Rapid improvements in science and technology are closing in on a more definitive answer to Magnus’ question.

More Information

• NASA Media Page: “Scientists Discover Record Fifth Planet Orbiting Nearby Star“