Artists impress of Chandrayaan-1 at the moon. Credit: ISRO
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Following the fifth and final orbit raising maneuver which put Chandrayaan-1 closer to the moon, the spacecraft snapped the first picture of its final destination. This clear, crisp image of the moon While the images are still being processed and are not available yet, mission managers says the images bode well for spacecraft’s mission to map the entire moon’s surface with its Terrain Mapping Camera. And all systems are go for the final maneuver on November 8, which will put Chandrayaan-1 in lunar orbit.
After launch on October 22, the spacecraft was first injected into an elliptical 7-hr orbit around Earth, at 255 km from Earth at perigee (its closest point) and 22,860 km away at apogee, its farthest point. After five engine firings, Chandrayaan-1 has spiraled outwards in increasingly elongated ellipses around Earth, until it reached its lunar transfer orbit on November 4.
Chandrayaan-1 in its lunar transfer orbit. Credit: ISRO
In the final maneuver, engineers fired the spacecraft’s 440 Newton liquid-fuel propelled engine for about two and a half minutes. The lunar transfer orbit’s farthest point from Earth is about 380,000 km.
On November 8, as it nears the moon, the spacecraft’s engine will be fired again to slow the spacecraft, allowing the moon’s gravity to capture it, and then it will go into an initial elliptical orbit around the moon. A group of engineers from JPL are assisting the engineers from India, acting as experienced back-up for the “first-time-flyers” from India. And everything has gone smoothly thus far.
The spacecraft will make observations from the initial orbit, and then the orbit will be lowered a 100 km circular polar orbit. Following this, the Moon Impact Probe (MIP) will be ejected, impacting the lunar surface. Then the main mission will begin with Chandrayaan-1 exploring the moon from orbit with its array of instruments for two years.
Water ice in a North Pole crater. Credit: ESA/DLR/FU Berlin (G. Neukum).
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In December, the Mars Express spacecraft will celebrate the fifth anniversary of its arrival at Mars. In observation of this milestone the German Aerospace Center DLR has put together a collection of some of the best images from the High-Resolution Stereo Camera (HRSC), the main camera on board the spacecraft. The stunning, high resolution images this instrument has produced of Mars’ surface are nothing short of jaw dropping, and they have provided new perspectives and new discoveries about our neighboring planet. One of the iconic images from Mars Express is the image above of water ice inside a crater near Mars North Pole.
And here’s more from The Best of Mars Express:
Echus Chasma mosaic. Credits: ESA/DLR/ FU Berlin (G. Neukum)
My personal favorite is the image above of Echus Chasma, located in the Lunae Planum high plateau, north of Valles Marineris the ‘Grand Canyon’ of Mars. It doesn’t take much imagination to consider the possibility that once, gigantic water falls may have plunged over these 4,000 meter high cliffs on to the valley floor. See more of Echus Chasma here.
Here’a another of my favorites, this perspective color view of Coprates Chasma and the “Grabenkette” (a chain of depressions or rifts in Mars’ surface) Coprates Catena in an eastern section of Valles Marineris.
The ability of the HRSC to provide “perspective” views — images that are not just straight down camera shots — are what sets the Mars Express mission apart from all the other orbiting spacecraft. When seen in full resolution (please, go download the biggie image here) these 3-D perspective views, are mind blowing!
Hebes Chasma Credit: ESA/DLR/FU Berlin (G. Neukum).
The HRSC is imaging the entire planet in full color, 3-D and with a resolution of about 10 meters. Selected areas will be imaged at two-meter resolution. One of the camera’s greatest strengths is he unprecedented pointing accuracy achieved by combining images at the two different resolutions. Another is its ability for 3-D imaging which reveals the topography of Mars in full color.
Mars North Pole. Credit: ESA/DLR FU Berlin (G. Neukum)
Here’s another look at Mars north arctic region, with water ice visible in Chasma Boreale.
Below is a view of Aureum Chaos, located in the eastern part of Valles Marineris. This “chaotic” landscape is dominated by randomly oriented, large-scale mesas and knobs that are heavily eroded. These mesas range from a few kilometres to tens of kilometers wide. Perspective colour view of Aureum Chaos, northerly direction. Credit: ESA/DLR/FU Berlin (G. Neukum).
For a little more history on Mars Express, the spacecraft was launched on June 2, 2003 from Baikonur Cosmodrome on a Soyuz-Fregat rocket. The goal of Mars Express is to search for water and the possibility of Martian life. Mars Express is a European Space Agency (ESA) mission to the Red Planet involving a consortium of countries (primarily France, Germany, Great Britain, Ireland, Italy, Japan, the Netherlands, Norway, Russia, Sweden, Spain, and the United States). The mission consisted of the orbiter and the Beagle lander, which unfortunately crash landed on Christmas Day 2003. Mars Express is currently in its second mission extension, which goes until May 2009. Phobos from Mars Express. Credit: ESA/DLR/FU Berlin (G. Neukum).
And finally, Mars Express not only takes images the surface of the Red Planet, but also of Mars’ moon Phobos. On July 23 of this year, the spacecraft flew only 93 kilometers from Mars’ moon Phobos, and took the most detailed images ever of the small, irregular moon. Read more about the flyby here.
That’s just a taste of all the wonderful images taken in the last five years by Mars Express. Check out more images at the DLR site.
Artist impression of the surface of Enceladus and the source of the plumes (BBC/Karl Kofoed)
[/caption]Having just returned the most detailed images yet of Saturn’s 500km-wide moon Enceladus, it is little wonder scientists are excited about this mysterious natural satellite. However, in new research recently published, the results aren’t related to the recent “skeet shot” Cassini carried out above the moon’s south pole (although there is some common ground). The paper’s origins started out in July 2005 when Enceladus’ plume of gas (containing organic compounds) was discovered fizzing from the moon’s surface, inside the “tiger stripes” just imaged by Cassini.
In some computer models, this plume is attributed to a sub-surface ocean. This possibility has led scientists to speculate that it might be an ideal environment for basic forms of life to thrive. What’s more, although the Cassini spacecraft isn’t equipped to directly search for life, it may be able to detect the signature of life…
Point of interest: The four long fissures straddle the south pole of Enceladus and run for more than 100 kilometres – the circular grid marks 60° South (NASA)This new research published in the journal Astrobiology and led by Christopher McKay at NASA’s Ames Research Center in Moffett Field, suggests that the Cassini probe may have already collected data that could be analysed in the search for extraterrestrial life. By sifting through the data collected by the Saturn spacecraft after it passed though the plume of gas and ice particles emitted from Enceladus’ south pole, organic chemicals, such as methane, have been detected.
As Nancy wrote earlier today in relation to the search for life on Mars, methane is a key by-product from biological processes on Earth. It seems that Enceladus has a whole cocktail of the key components for life blasting into space.
“If you think about what you need for life, you need water, energy, organic material, and you need nitrogen, and they’re all coming out of the plume,” McKay said. “Here is a little world that seems to have it all.”
So what could be producing this possible biological signature? It seems possible that micro-organisms known as methanogens (as the name suggests, they produce methane as a gaseous by-product to their biological cycles) could be a possible explanation, but there must be the correct ratio of organic compounds (in favour of methane) present in the plume for this to be the case.
Life's smoking gun? The plume above Enceladus (NASA)McKay’s team argues that for the organic compounds found in Enceladus’ plume to be of biological origin, there should be a much higher concentration of methane than any heavier organic compound (i.e. non-methane hydrocarbons). McKay’s paper suggests that the non-methane hydrocarbon to methane ratio needs to be lower than 0.001 for the methane to favour a biological origin.
This method was recently used on hydrothermal vents at the bottom of the Atlantic ocean. A higher ratio of non-methane hydrocarbons were measured, indicating the gases emitted from the vents were non-biological in origin. This research suggests that Cassini’s Ion and Neutral Mass Spectrometer (INMS) can be used in a similar way to see if the organic compounds detected in the Enceladus plume can be attributed to biological processes.
However, previous fly-bys of the plume suggest it is very comet-like (and therefore an ancient source of organic compounds), so more data needs to be collected and better models need to be devised.
This research is very encouraging for the future exploration of the Solar System’s gas giant moons, and it is hoped that more sensitive equipment can be put into Saturn orbit in the future to possibly refine the preliminary results from Cassini. Whether the organic compounds in Enceladus’ south polar plume can be attributed to biological processes, or not, will probably have to wait a while yet…
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The Cassini spacecraft performed another ‘skeet shoot’ over Enceladus’ south pole on Friday, and returned some absolutely stunning images. Or as Carolyn Porco, the imaging team leader for the spacecraft said, “a bounty of positively glorious views of one of the most fabulous places in the solar system.” The resolution of the mosaic shown here is just 12.3 meters per pixel! Visible are large house-sized boulders, and the deep “tiger stripes” from which the plumes of material are being produced. One source of the jets producing the plumes is identified in the upper right on this image. Enjoy these great images now because the next flyby of Enceladus won’t be for another year. And at that time, the sun won’t be shining as predominantly on moon’s south pole, so next year the view of this region of Enceladus will be much dimmer. Here’s more…
This Cassini image was the first and highest resolution ‘skeet shoot’ narrow angle image captured during the October 31st flyby of Enceladus.
The image was taken with the Cassini spacecraft narrow-angle camera on October 31, 2008 at a distance of approximately 1691 kilometers (1056 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 78 degrees. Image scale is 9 meters (30 feet).
Enceladus. Credit: CICLOPS
Here’s the 8th image from the flyby using the narrow angle camera The source region for jets II and III are identified. To identify jet source locations on the surface, imaging scientists carefully measured the locations and orientations of individual jets observed along the moon’s limb in Cassini images taken from multiple viewing angles. For each jet measurement, the researchers then computed a curve, or ground track, on the surface of Enceladus along which that jet might lie. The researchers were able to isolate eight areas as jet sources.
The image was taken with the Cassini spacecraft narrow-angle camera at a distance of approximately 5568 kilometers (3480 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 75 degrees. Image scale is 32 meters (105 feet) per pixel. More Enceladus. Credit: CICLOPS
Update: 10/31: Phoenix communicated with NASA’s Mars Odyssey orbiter late Thursday. The communication reinforced a diagnosis that the spacecraft is in a precautionary mode triggered by low energy. Mission engineers are assessing the lander’s condition and steps necessary for returning to science operations.
The Phoenix Lander is not responding to attempts to communicate with it. Earlier today, we reported that Phoenix had gone into safe mode. The lander experienced a low-power fault in the electrical system due to the reduction of solar-electric power to shorter daylight hours and a dust storm, as well as extremely cold weather. Engineers for the mission were able to send a command to restart a battery that had shut off, and were hopeful that further communications would resume without incident. However, Phoenix did not respond to one of the Mars orbiter’s attempt to communicate with it Wednesday night and Thursday morning.
I don’t know about the rest of you, but I’m not ready to say goodbye to Phoenix quite yet…
Mission controllers believe the most likely situation to be that declining power has triggered a pre-set precautionary behavior of waking up for only about two hours per day to listen for an orbiter’s hailing signal. If that is the case, the wake-sleep cycling would have begun at an unknown time when batteries became depleted.
“We will be coordinating with the orbiter teams to hail Phoenix as often as feasible to catch the time when it can respond,” said Phoenix Project Manager Barry Goldstein at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “If we can reestablish communication, we can begin to get the spacecraft back in condition to resume science. In the best case, if weather cooperates, that would take the better part of a week.”
Artist concept of the Phoenix lander. Credit: NASA
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Cold weather and a dust storm are likely contributors to why NASA’S Phoenix Mars Lander went into a “safe mode” late Tuesday. The lander experienced a low-power fault in the electrical system. While engineers anticipated that a fault could occur due to the diminishing power supply, the lander also unexpectedly switched to the “B” side of its redundant electronics and shut down one of its two batteries. During safe mode, the lander stops non-critical activities and awaits further instructions from the mission team. The good news is that within hours of receiving information of the safing event, mission engineers at JPL and Lockheed Martin in Denver, were successfully able to send commands to restart battery charging. So, it is not likely that any energy was lost. And Phoenix is still Twittering,, which is good news, too!
Weather conditions at the landing site in the north polar region of Mars have deteriorated in recent days, with overnight temperatures falling to –141F (-96C), and daytime temperatures only as high as -50F (-45C), the lowest temperatures experienced so far in the mission. A mild dust storm blowing through the area, along with water-ice clouds, further complicated the situation by reducing the amount of sunlight reaching the lander’s solar arrays, thereby reducing the amount of power it could generate. Low temperatures caused the lander’s battery heaters to turn on Tuesday for the first time, creating another drain on precious power supplies.
Science activities will remain on hold for the next several days to allow the spacecraft to recharge and conserve power. Attempts to resume normal operations will not take place before the weekend.
“This is a precarious time for Phoenix,” said Phoenix Project Manager Barry Goldstein of JPL. “We’re in the bonus round of the extended mission, and we’re aware that the end could come at any time. The engineering team is doing all it can to keep the spacecraft alive and collecting science, but at this point survivability depends on some factors out of our control, such as the weather and temperatures on Mars.”
The ability to communicate with the spacecraft has not been impacted. However, the team decided to cancel communication sessions Wednesday morning in order to conserve spacecraft power.
Just a day ago, the mission announced plans to turn off four heaters, one at a time, in an effort to preserve power. The faults experienced late Tuesday prompted engineers to command the lander to shut down two heaters instead of one as originally planned. One of those heaters warmed electronics for Phoenix ‘s robotic arm, robotic-arm camera, and thermal and evolved-gas analyzer (TEGA), an instrument that bakes and sniffs Martian soil to assess volatile ingredients. The second heater served the lander’s pyrotechnic initiation unit, which hasn’t been used since landing. By turning off selected heaters, the mission hopes to preserve power and prolong the use of the lander’s camera and meteorological instruments.
But everything is on a downward trend. As the Martian northern hemisphere shifts from summer to autumn, less sunlight is reaching Phoenix’s solar panels. “It could be a matter of days, or weeks, before the daily power generated by Phoenix is less than needed to operate the spacecraft,” said JPL mission manager Chris Lewicki. “We have only a few options left to reduce the energy usage.” But Phoenix is into the fifth month of a 90-day mission — we should all be thankful we’ve had the little lander with us for as long as we have….
It appears the end is nigh for the Phoenix Mars Lander. Today, engineers have begun to shut down some of the lander’s instruments and heaters. But this is in hopes of extending the mission by saving power as available sunlight begins to wane with the approach of Martian autumn. But at the same time, the spacecraft requires more power to run heaters in order to survive as the temperatures decline. “If we did nothing, it wouldn’t be long before the power needed to operate the spacecraft would exceed the amount of power it generates on a daily basis,” said Phoenix Project Manager Barry Goldstein of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “By turning off some heaters and instruments, we can extend the life of the lander by several weeks and still conduct some science.”
Today, commands were sent to disable the first heater, one that warms the robotic arm, the robotic arm camera and the TEGA instrument – the Thermal and Evolved Gas Analyzer. Likely, this means no more digging and no more “baking and sniffing” of soil samples. Engineers say by shutting down this heater, they’ll save 250 watt-hours of power.
Before power was shut down to the arm and the camera, Phoenix took one last image of the “Holy Cow” ice patch underneath the lander.
Over the next several weeks, four survival heaters will be shut down, one at a time, in an effort to conserve power. The heaters serve the purpose of keeping the electronics within tested survivable limits. As each heater is disabled, some of the instruments are also expected to cease operations. The energy saved is intended to power the lander’s main camera and meteorological instruments until the very end of the mission.
Engineers are also preparing for solar conjunction, when the sun is directly between Earth and Mars. Between Nov. 28 and Dec. 13, Mars and the sun will be within two degrees of each other as seen from Earth, blocking radio transmission between the spacecraft and Earth. During that time, no commands will be sent to Phoenix, but daily downlinks from Phoenix will continue through NASA’s Odyssey and Mars Reconnaissance orbiters. At this time, controllers can’t predict whether the fourth heater would be disabled before or after conjunction.
In the final step, Phoenix engineers may turn off a fourth heater — one of two survival heaters that warm the spacecraft and its batteries. This would leave one remaining survival heater to run out on its own.
“At that point, Phoenix will be at the mercy of Mars,” said Chris Lewicki of JPL, lead mission manger.
The Phoenix team has parked the robotic arm on a representative patch of Martian soil. No additional soil samples will be gathered. The thermal and electrical-conductivity probe (TECP), located on the wrist of the arm, has been inserted into the soil and will continue to measure soil temperature and conductivity, along with atmospheric humidity near the surface. The probe does not need a heater to operate and should continue to send back data for weeks.
Throughout the mission, the lander’s robotic arm successfully dug and scraped Martian soil and delivered it to the onboard laboratories. “We turn off this workhorse with the knowledge that it has far exceeded expectations and conducted every operation asked of it,” said Ray Arvidson, the robotic arm’s co-investigator, and a professor at Washington University, St. Louis.
After a successful maneuver early today (October 26, 2008), the Chandrayaan-1 spacecraft has crossed the 150,000 km distance mark from Earth, officially entering deep space, on course for the moon. This was the third orbit raising maneuver of the mission. The spacecraft’s 440 Newton liquid engine was fired for about nine and a half minutes, beginning at 07:08 IST. With this, Chandrayaan-1 entered a much higher elliptical orbit around the Earth. The apogee (farthest point from Earth) of this orbit lies at 164,600 km while the perigee (nearest point from Earth) is at 348 km. In this orbit, Chandrayaan-1 takes about 73 hours to go round the Earth once.
To compare, Chandrayaan’s initial orbit had a perigee of 255 km and an apogee of 22,860 km, with about a 6.5-hour period. After the second boost from its engines, Chandrayaan raised its apogee to 37,900 kilometers, and increased its orbit period to 11 hours.
Engineers from the Jet Propulsion Laboratory are also providing backup navigation assistance to the Indian Space Agency in Bangalore, India, by helping to track the flight dynamics. The antennas of the Indian Deep Space Network at Byalalu are being used for tracking and communicating with Chandrayaan-1 spacecraft in its high orbit. From the image below, you can see how additional orbit raising maneuvers in the next few days will take Chandrayaan-1 towards the Moon, and then into lunar orbit. Currently, the spacecraft is scheduled to reach lunar orbit on November 8. Chandrayaan mission profile. Credit: ISRO
High-resolution view of the lunar surface (JAXA/SELENE)
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It’s been a long-held belief that the Moon is hiding significant quantities of water ice, safe from the Sun’s ablative effects inside shady craters. One such crater is called Shackleton at the lunar South Pole and previous Moon missions have indicated it might hold a large reservoir of ice for all the water needs of future Moon colonists. Alas, the Japanese lunar mission Kaguya (or the Selenological and Engineering Explorer – “SELENE”) has taken a peek into the crater to find… nothing. At least, it hasn’t spotted any significant quantities of surface ice. So where does this leave future lunar colonies?
In 1994, the US Clementine lunar orbiter (a joint venture between NASA and the Ballistic Missile Defense Organization) carried out the “Bistatic Radar Experiment” which involved bouncing radio signals from the probe’s transmitter from the lunar poles. The reflected signal was then received by the Deep Space Network antennae on Earth. Scientists deduced from the reflected signal that volatile ices were present in the lunar regolith, most probably water ice. However, this claim was disputed after a similar experiment was done using the Arecibo radio telescope in Puerto Rico. This time, radio signals were reflected from regions on the Moon bathed in sunlight (where it would be impossible for water ice to survive) and identical results to the Clementine mission were found.
NASA’s 1998 Lunar Prospector also had mixed results. Using its Neutron Spectrometer (NS) instrument, the probe had detected large quantities of water, leading NASA to make the estimate that 3 billion metric tons of water ice was located at or near the surface of the Moon in its polar regions. However, when the mission ended in 1999, the Lunar Prospector was deliberately crashed into a crater in the lunar South Pole in the hope of kicking up a plume of lunar surface material and detecting water ice from Earth. Unfortunately, no water was discovered. (Out of interest, the Lunar Crater Observation and Sensing Satellite, set for launch in April 2009, has a similar suicidal goal to put a divot in the Moon.)
Now, using the Japanese lunar mission Kaguya, scientists have taken the opportunity to have a closer look into the Shackleton crater, the most likely candidate to have a supply of water ice shaded from the Sun. As there is no atmosphere (apart from some very tenuous outgassed chemicals), sunlight cannot be scattered into the bottom of the crater to illuminate its surface. However, scientists have taken images during lunar mid-summer when enough light is scattered off the crater’s upper inner wall to faintly brighten the darkness below.
Although it is very cold inside the crater (-183°C or -297°F), certainly ideal conditions to preserve ice, there is no visual evidence of any surface ice at all.
Although this isn’t great news for future lunar colonists, don’t pack up your Moon buggies quite yet. The Japanese team have concluded that although there is no visual brightening due to ice, water ice may be mixed in low quantities with the lunar dirt. Or there’s simply no ice in Shackleton crater. Either way, I wouldn’t suggest mounting a manned expedition to Shackleton any time soon…
One of the wonderful things about space exploration and astronomy is how it brings people together across cultures, countries and even languages. Almost all of the current planetary missions — Phoenix, Cassini, and Dawn, for example — are collaborative efforts between scientists and space agencies around the world. And all of our explorations, whether it be through spacecraft or telescopes embody the best of all of humanity: our creativity, our technological advances, our driving curiosity and spirit of perseverance. Furthermore, these explorations excite and inspire us, and also bring us together, providing a common bond. A friend that’s involved with the Chandrayaan mission, (JPL and ISRO working together) that’s now working its way to the Moon, sent me a link to a home video showing Chandrayaan’s launch. You don’t have to speak the language of India to understand how absolutely excited these people were to see their own country’s spacecraft rocket to space. See the video below:
You can’t help but cheer along with the people in the video. We can all cheer, and whoop and holler in excitement in the same language; no translations needed. Congrats to India and all the countries involved in the Chandrayaan mission. Woo hoo! and Yippee!!
