I had already posted about Cassini’s August 11th very close flyby of Saturn’s moon Enceladus, and some of the amazing images it captured, but this mosaic warrants posting as well. It is a composite of eight images from Cassini that have been stitched together. The image above is shown in enhanced color and Enceladus would not actually look like this to the human eye. Enhanced color, in this case achieved using a combination of five different lenses, is used to bring out more feature differentiation and detail for analysis, things like the four south polar sulci (which are surface depressions or fissures, and often referred to as Enceladus’ “tiger stripes”) visible in this mosaic. To the human eye Enceladus would look more like below, the starkly stunning image that led my previous post on Enceladus:
Saturn’s moon Enceladus, pictured above in a full color image from a flyby in 2005 and written about on schneiderism before, received a close visit from the Cassini robotic explorer on August 11th. This flyby allowed Cassini to snap incredible surface detail images. The following are some of the more compelling pictures to come out of this flyby.
Below is an image of “The Mound,” which is the object in the center right of the image which is casting a long shadow to the right. The incredible detail of this photo shows us the complexity of ridges, fissures, and cracks that makes up the surface of Enceladus, looking almost like a close-up image of elephant skin.
One thing that Cassini potentially revealed is evidence of the active venting occurring on Enceladus, venting observed by Cassini on previous missions. The image below appears to show this venting in progress, and in detail. Looking at the center of the image, note the blurred whisps over the whitish fissure feature. Serious speculation suggests that we’re seeing active venting right there:
Cassini was able to get very close to Enceladus, much closer than previous visits, and the images below show the high detail that this made possible. The first was taken by Cassini at a distance of about 1600 miles, the second even closer taken from about 975 miles. Both are incredible.
From 1600 miles:
From 975 miles:
I do not think that we can overstate how incredible it is to be seeing the surface of Enceladus in such rich detail, truly an important and amazing accomplishment. These images are a treasure trove of information for researchers and scientists seeking to learn more about our solar system.
More on Cassini’s August 11th flyby of Enceladus at wanderingspace, and a very informative article on Enceladus can be found at The Planetary Society.
There’s milestones, and then there’s MILESTONES. The Hubble Space Telescope seems to have achieved quite a few while making it look somewhat easy, though lately it has again run into some technical difficulties. As Hubble rounds out its 18th year in Earth orbit, its orbital counter has passed the 100,000th mark (100,023 at this writing) which is itself an interesting accomplishment. This translates into 2.72 billion miles traveled, which is altogether impressive. All of this, of course, while it has remained just a few miles above the Earth’s surface, snapping pictures like this:
Today, July 29, 2008, marks the 50th anniversary of the inception of the National Aeronautics and Space Administration. The year was 1958, the race for space was heating up fast with the Soviet’s successful launch of the first orbiting satellite, Sputnik, in October of 1957. NASA was, in many ways, a reaction to this event. That first team for NASA came out swinging, though, and they set about an intense range of projects motivated by the urgings of a passionate President. The first 25 years saw amazing accomplishments (Mercury, Apollo, putting astronauts on the moon, Viking, Voyager, Mariner, Skylab, the space-shuttle…) relatively swelled budgets, and endless manpower. The next 25 also saw great accomplishments (Hubble, ISS, Cassini, Mars exploration…), but mixed with the challenges of changed national priorities, increased international competition, the limitations of the space-shuttle, the slowed progress of the ISS, and budgetary constraints. Along the way there have been horrible tragedies and incredibly prolific failures, but when you push the technological envelope and seek to expand the boundaries of human experience there are inevitable risks involved. The astronauts that have died knew these risks well, and still came to work. I would like to believe that the tragedies have been more than balanced by the successes, by the amazing discoveries, and by the advancement of science. NASA has inspired generations, myself included, and provided the United States with a vital rallying point for an optimistic belief in the future of our nation, and for humanity. From those that have been inspired by NASA have sprung incredible private space ventures like that of Burt Rutan and Richard Branson, the Lunar X Prize, and the inevitable development of space tourism.
NASA is definitely not without its problems, but what large publicly funded organization isn’t? The fact is that NASA has been with us for 50 years, has achieved a great deal, and has a plan for the future of the United States in space.
I subscribe to the NASA RSS feed for the Cassini-Huygens mission and just came upon this image taken back on June 10th of this year. This simple black and white image taken by Cassini conveys so much detail about the icy moon. There is the surface, riddled with impact craters and covered in ridges and striations. If you look at the upper right edge of the moon silhoetted against the blackness of space you get a sense of the dimensionality of the moon’s surface. Rhea is the second largest of Saturn’s moons at about 950 miles across, this image definitely gives it presence. Some more detail on Rhea:
Rhea was discovered in 1642 by Giovanni Cassini, the namesake for the Cassini space probe and the astronomer who also discovered the Saturn moons Iapetus, Dione, and Tethys
In direct sunlight the temp is as warm as -281°F, and in the shade -364°F
Rhea has a rocky core that is about one-third of its mass, the rest is water-ice
Catching up on the deluge that is my RSS reader lately, I came across this image from APOD of the Caloris basin (also called Caloris Planitia) on Mercury recently snapped by the Mercury Messenger robotic explorer. It’s huge, and one of the largest impact basins from an asteroid-sized object in our solar system. The basin measures over 1,500 km across. The image above is a false color image in order to enhance details not visible in a true color image. The yellowish object dominating the image is obviously the impact crater of the Caloris basin, but the orange spots above denote volcanic activity on Mercury, which is new evidence provided by Messenger that the smooth plains of Mercury are actually lava flows.
I had previously written about Mercury and NASA’s Messenger mission here and here.
NASA engineers have been busy testing robotic mobility prototypes for potential use on future missions to the moon and Mars. The engineers, in full astronaut gear, have been putting the machines through their paces on terrain at Moses Lake, Washington that approximates the mobility challenges of navigating the surface regolith of the moon.
The robotic prototypes tested include the twelve wheeled robotic transport pictured above, as well as a six-legged all-terrain vehicle that can carry large payloads, an autonomous drilling rover and a mapping robot. There is an incredibly large and well-shot image gallery of the testing, and the various robotic vehicles, here that is worth viewing. The public was invited to observe, which is further proof of the efforts that NASA is undertaking to engage the public and enlist their enthusiasm. NASA’s relatively recent adoption of social media as a way to create dialog with the public is an additional indicator of a changed view of the role of the public in space exploration.
Over the past two years astronomers at NASA’s Meteoroid Environment Office have observed over one hundred explosions on the moon’s surface. These explosions are the results of impacts by meteoroids and have measured as powerful as a few hundred pounds of TNT. It is no surprise that the moon suffers impacts, look at the image of the moon’s surface above. What is interesting is the observable frequency of these impacts in the last 24 months, which is quite a bit more intense than astronomers were expecting. This is an important phenomena for NASA to observe and understand as we get closer to the reality of a new effort to send astronauts to the moon and eventually set up a permanent lunar base. Essentially, there is no place on the moon that is impact free, nor is there a time that is less intense for impacts than others. The image below depicts the locations of the recorded impacts since initiation of the program:
The frequency and explosive power of these impacts pose a number of challenges to lunar astronauts, not so much from the risk of a direct hit but more from the risk of a secondary hit by one of the millions of particles that the explosions create and that shoot out from the impact area like bullets. A piece of debris 1 millimeter in diameter could penetrate an astronauts suit and damage equipment.
The first impact was recorded very shortly after the initiation of the moon impact observation program and recorded the strike of a meteoroid about the size of a baseball. Most of these impacts are the result of small meteoroids, some little bigger than a small rock or pebble, but they are traveling in excess of 30,000mph and hit the moon with incredibly violent force. A meteoroid the size of a pebble can create a crater several feet across.
This image is the result of the Mars Phoenix mission team instructing the robotic arm camera to look under the vehicle. What you are looking at is the surface of Mars, and it shows that the Martian soil has been displaced by the landing thrusters on Phoenix to expose what is most probably ice. The simple action of Phoenix landing on Mars has potentially exposed polar ice directly under the vehicle, ice that was covered by a very loose and thin layer of soil.
There is a rumor that when the mission leaders saw this image the first words uttered were “Holy cow!”
The Phoenix robotic explorer has been on Mars now for about 27 hours after an incredibly successful entry, descent and landing. It has been very busy. Incredible images are already streaming to Earth, and those of us geeked out by things of this nature are absolutely riveted. I was excited to discover how many people I know were following @MarsPhoenix on Twitter.
Many images are coming back, and most right now are of the explorer itself and the immediate vicinity as the mission managers check systems and get their bearings. The above image of one of the craft’s landing pads is one of my favorites because that image is of the pad of a man-made robotic explorer sitting on the surface of Mars millions of miles away from Earth, and it was taken in the last 24 hours. Astounding. Even more astounding is this video composite of the Martian surface, terrain and horizon taken by Phoenix today.
We are at just under four hours before Phoenix lands on the surface of Mars. I am checking periodically at the Phoenix mission control website in anticipation of this event. Martian weather is clear and the landing later today is green for go. I suspect there are a lot of very excited and anxious people at JPL right now.
The above animation is of weather on Mars around its north pole from 5/16 through 5/22. The small cigar shaped outline in the upper left quadrant is the planned landing zone.
It’s not just a big day for race fans, its a big day for science and space enthusiasts. In August of last year the Mars Phoenix Explorer left Earth to start its journey to Mars. Its mission is to arrive safely, land on the Martian North Pole, and dig into the soil there begin looking for the building blocks of life. It arrives today at around 4:45PM PDT. Arriving is the hardest part, as now the explorer has to successfully enter the Martian atmosphere (at 12,000mph) using parachutes to slow the rapid descent from 900mph to 250mph, and then fire landing rockets to prevent it from slamming into the Martian surface (see the video above). Its a complex landing, and the mission control team probably hasn’t been sleeping much these last few days, as the last five years of their work culminates today in about seven minutes of anxiety. That’s okay, though, as they have a number of ways they can distract themselves while keeping us updated on the the mission’s progress. For instance, you can follow the Phoenix mission on Twitter and get frequent updates and mission facts. The mission team also has a blog that is full of information and that will be used to post what the mission team is thinking and what Phoenix sees and discovers, as well as an information rich mission website.
So, the entire Phoenix mission is going to be captured for us via an array of online tools. This is incredibly exciting, and it serves to connect us to the exploration and science that NASA leads in a way that is not only meaningful, but also basically real time.
I have posted previously about the planet Mercury, so I was excited to learn that the robotic Mercury research spacecraft Messenger had sent back it’s first image of the planet, the first since Mariner 10 visited Mercury 30 years ago. Messenger stands for the MErcury Surface, Space ENvironment, GEochemsitry, and Ranging mission.The image above was was taken on January 11 as Messenger approached Mercury (at just over 1 million miles from the planet). Scheduled for Monday is a pass at about 125 miles over Mercury’s surface. The plan is for Messenger to make two more close passes (in October 2008 and September 2009) before settling into orbit in March of 2011 and initiating its mission of mapping the surface of Mercury in detail. And in color.
Mercury is the fastest planet in our solar system, and the maneuvering that Messenger will have to do (see graphic below from the Messenger website) to comfortably settle into an observational orbit is complex. It involves the three flybys mentioned to help the craft build up enough speed to match Mercury as it settles into orbit, called “Mercury Orbit Insertion,” or MOI. Messenger will also use a series of trajectory corrections and deep space maneuvers achieved by the controlled firing of its thrusters.
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