Phoenix's scoop hovers over TEGA. Credit: NASA/JPL/Uof Arizona
[/caption]
NASA’s Phoenix Mars Lander scraped up some icy soil with its robotic arm and scoop and then attempted to quickly deliver the sample to the oven on board. But not enough soil made it to the oven; the icy soil stuck to the scoop. Engineers determined the rasping and scraping activity collected a total of 3 cubic centimeters of icy soil, more than enough to fill the tiny oven cell of the Thermal and Evolved-Gas Analyzer, or TEGA. However, images returned from the lander Saturday showed that much of the soil remained lodged in the robotic arm’s scoop after the delivery attempt. “Very little of the icy sample made it into the oven,†said Barry Goldstein, Phoenix project manager. “We believe that the material that was intended for the targeted cell is the material that adhered to the back of the scoop.â€
Once the sample had been collected, the robotic arm tilted its scoop and ran the rasp motor several times in an attempt to sprinkle the sample into the oven whose doors were wide open. The scoop was then inverted directly over the doors. A screened opening over the oven measures about 10 centimeters (4 inches) long by 3 centimeters (1.5 inches) wide. The oven itself is roughly the size of an ink cartridge in a ballpoint pen.
But TEGA’s sensors didn’t detect enough soil in the oven for the oven doors to close. Commands were also sent to vibrate the screen on TEGA several times. The good news there is that the vibrating did not cause the oven to short circuit, a problem that occurred earlier and engineers have been worried that vibrating could possibly short out the entire instrument. But TEGA lives on for the team to try again to quickly deliver the icy soil to the oven before the ice sublimates away in Mars thin atmosphere. The ice can exist just under Mars surface, protected by the soil.
Goldstein said the team will adjust their sample drop-off strategy and try again.
Project Lucifer. Could the plutonium fuel onboard the Cassini mission cause a nuclear chain reaction on Saturn? Credit: NASA/US Department of Defense
[/caption] The story: On October 15th 1997, the Cassini-Huygens mission blasted off from Cape Canaveral Air Force Station to explore Saturn and its moons. It continues to study the ringed gas giant today and its mission has been extended till 2010. Cassini is is powered by 32.8 kg (72 lbs) of plutonium fuel. A radioactive power source is the only option for missions travelling beyond the orbit of Mars as sunlight is too weak for solar panels to be effective. However, NASA (in association with secret organizations, such as the Illuminati or the Freemasons) wants to use this plutonium for a “higher purpose”, dropping Cassini deep into Saturn at the end of its mission where atmospheric pressures will be so large that it will compress the probe, detonating like a nuclear bomb. What’s more, this will trigger a chain reaction, kick-starting nuclear fusion, turning Saturn into a fireball. This is what has become known as The Lucifer Project. This second sun will have dire consequences for us on Earth, killing millions from the huge influx of radiation by this newborn star. Earth’s loss becomes the Saturn moon Titan’s gain, suddenly it is habitable and the organizations playing “God” can start a new civilization in the Saturn system. What’s more, exactly the same thing was attempted when the Galileo probe was dropped into Jupiter’s atmosphere in 2003…
The reality: Now that the Cassini mission has been extended by two years, we can expect this conspiracy theory to become more and more vocal in the coming months. But like the Galileo/Jupiter/second sun theory, this one is just as inaccurate, once again using bad science to scare people (much like Planet X then)…
So what happened when Galileo dropped into Jupiter? Galileo undergoing preparations before launch in 1989. Credit: NASA
Well… nothing really.
In 2003, NASA took the prudent decision to terminate the hugely successful Galileo mission by using its last drops of propellent to push it at high speed into the gas giant. By doing so, this ensured the probe would burn up during re-entry, dispersing and burning any contaminants (such as terrestrial bacteria and the radioactive plutonium-238 fuel on board). The primary concern about letting Galileo sit in a graveyard orbit was that if mission control lost contact (very likely as the radiation belts surrounding Jupiter were degrading the probe’s ageing electronics), there may have been the possibility that Galileo would crash into one of the Jovian moons, contaminating them and killing any possible extra-terrestrial microbial life. This was a serious concern, especially in the case of Europa which could be a prime location for life to thrive below its ice-encrusted surface.
Now this is where the intrigue begins. Long before Galileo plummeted into Jupiter’s atmosphere, conspiracy theorists cited that NASA wanted to create an explosion within the body of the gas giant, thus igniting a chain reaction, creating a second sun (Jupiter is often called a ‘failed star’, although it has always been way too small to support nuclear reactions in its core). This was proven wrong on many counts, but there were three main reasons why this could not happen:
The design of the radioisotope thermoelectric generators (RTGs) supplying energy to the craft wouldn’t allow it.
The physics behind a nuclear explosion (nuclear fission) wouldn’t allow it.
The physics of how a star works (nuclear fusion) wouldn’t allow it.
Five years after the Galileo impact, Jupiter still looks to be in fine health (and it certainly isn’t close to being a star). Although history has already proven you can’t create a star from a gas giant using a space probe (i.e. Jupiter + Probe ≠ Star), conspiracy theorists think that NASA’s evil plan failed and there is some evidence that something did happen after Galileo got swallowed by Jupiter (and that NASA is pinning their hopes on the Cassini/Saturn combo).
Cue the Big Black Spot
The mystery black spot in 2003 (by Eric Ng) compared with one of the Shoemaker-Levy 9 fragments impact sites in 1994 (NASA)
Backing up the conspiracy theorists’ claims that there was an explosion inside the Jovian atmosphere after Galileo hit was the discovery of a dark blob near the equator of Jupiter a month after the event. This was widely reported across the web, but only a couple of observations were made before it disappeared. Some explanations pointed out that the blob could have been a short-lived dynamic atmospheric feature or it was a shadow from one of the Jovian moons. After this initial excitement, nothing else surfaced about the phenomenon. However, some were keen to point out that the dark patch on Jupiter’s surface may have been a manifestation of a nuclear detonation from Galileo deep within the planet which, after a month, eventually floated to the surface. Comparisons had even made with the 1994 features generated by the impact of the pieces of Comet Shoemaker-Levy 9 (pictured above).
What ever the cause of this dark feature, it didn’t come from Galileo as a nuclear detonation simply was not possible. What’s more, a nuclear detonation from the Cassini mission when it enters Saturn’s atmosphere in 2010 is also impossible, and here’s why…
The Radioisotope Thermoelectric Generators (RTGs) The Cassini RTG, one of three on board. Credit: NASA
RTGs are a tried and tested technology in use since the 1960’s. Various RTG designs have been used on a huge number of missions including Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Galileo, Ulysses, Cassini and, most recently, New Horizons. RTGs are a very dependable source of power for space missions where solar panels have not been an option. For Cassini, if solar panels were used, they would need to have a huge area to collect the meagre sunlight at 10 AU, thus impractical to launch and operate.
The three RTGs on board Cassini are fuelled by small pellets of plutonium-238 (238Pu) encased separately in shock-proof containers known as general purpose heat source modules. There are 18 modules in each RTG. Through the use of thermocouples, the steady heat generated by the radioactive decay of the plutonium isotope is converted into electricity to supply Cassini. It is worth noting at this point that 238Pu is not weapon grade (i.e. it is very difficult to generate nuclear fission, 239Pu is more suited for this purpose). There are also dozens of Radioisotope Heater Units (RHUs) on board Cassini that provide a steady heat to critical subsystems, which contain single pellets of Pu-238. Again, these units are separated and shielded, each weighing 40 grams. For more details on this, check out the NASA Factsheet: Spacecraft Power for Cassini.
Inside an RHU and RTG (Roland Piquepaille)
Shielding is critical for each plutonium pellet, primarily to prevent radioactive contamination during launch of space missions. Should there be an incident during launch, space agencies such as NASA must assure the containment of the radioactive material. Therefore all RTGs and RHUs are completely safe regardless of the stresses they are put under.
So, like Galileo, Cassini will hit Saturn’s atmosphere at a high velocity (Galileo hit the Jovian atmosphere at a speed of 50 km/s) and disintegrate very quickly before burning to a cinder. The point I want to highlight here is that Cassini will break apart like any fast-moving object during re-entry.
Still, conspiracy theorists are quick to point out that Cassini is carrying a huge amount of plutonium, totalling 32.8 kg (even though it is not the weapon-grade 239Pu and all the bits of 238Pu are tiny pellets, encased in damage-proof containers, being scattered through Saturn’s atmosphere). But ignoring all the logical arguments against, it will still generate a nuclear explosion, right?
Alas, no.
So how does a nuclear bomb work anyway?
Artist impression of Galileo burning up when falling into the Jovian atmosphere. Credit: David A Hardy
For a general run-down of the basics behind a nuclear weapon, check out the very clear description at How Stuff Works: How Nuclear Bombs Work (scroll down to “Implosion-Triggered Fission Bomb,” as this is what the conspiracy theorists believe Cassini will emulate).
So there’s Cassini, plummeting through Saturn’s atmosphere in two years time. As it gets deeper, bits fall off and burnt by the friction caused by re-entry. When I say fall off, I mean they are no longer attached. For a nuclear detonation to occur we need a solid mass of weapon grade plutonium. By solid mass, I mean we need a minimum amount of the stuff for nuclear fission to occur (a.k.a. “critical mass”). The critical mass of 238Pu is approximately 10 kg (US DoE publication), so Cassini has enough 238Pu for three crude nuclear bombs (ignoring the fact that it is very difficult to build a 238Pu weapon in the first place). But how could all those tiny pellets of 238Pu be pulled together, in free-fall, casings removed, letting the pressure of Saturn’s atmosphere force it all together tipping it toward critical mass? Is that really possible? No.
An imploding nuclear weapon (answers.com)
Even if by some chance all the 238Pu in one RTG melded together, how would it detonate? For detonation of an implosion-triggered fission bomb to occur, sub-critical masses need to be forced together at the same instant. The only way this is possible is to surround the sub-critical masses with high-explosives so a shock wave rapidly collapses the sub-critical masses together. Only then may a chain reaction be sustained. Unless NASA has been really sneaky and hidden some explosives inside their RTGs, detonation is not possible. Using atmospheric pressure alone is not a viable explanation.
Now we can see that it is pretty much impossible for the plutonium on board Cassini to create a nuclear explosion. But if there was a nuclear detonation, could a chain reaction occur? Could Saturn become a star?
Mars' Midnight Sun. Credit: NASA/JPL-Caltech/U of Arizona/Texas A&M University
[/caption]
This panorama mosaic of images was taken by the Surface Stereo Imager on board NASA’s Phoenix Mars Lander. This mosaic documents the midnight sun during several days of the mission, from Sol 46, or the 46th day of the mission to Sol 56 (that would be to July 12 – 22, 2008 here on Earth.) The foreground and sky images were taken on Sol 54, when the lander pulled an all-nighter to coordinate work with the Mars Reconnaissance Orbiter. The solar images were taken between 10 p.m. and 2 a.m., local solar time, on the different nights of the 11 sol period. During this period, the sun’s path got slightly lower over the northern horizon, causing the lack of smoothness to the curve. This pan captures the polar nature of the Phoenix mission in its similarity to time lapse pictures taken above the Arctic Circle on Earth.
The latest activities of the lander has brought it closer to analyzing a sample of icy soil in the TEGA oven.
On Tuesday and Wednesday, Phoenix used its robotic arm to scrape the top of the hard layer in the trench called “Snow White.”
“We are monitoring changes between the scrapes,” said Doug Ming of NASA Johnson Space Center. “It appears that there is fairly rapid sublimation of some of the ice after scraping exposes fresh material, leaving a thin layer of soil particles that had been mixed with the ice. There’s a color change from darker to bluer to redder. We want to characterize that on Sol 58 to know what to expect when we scrape just before collecting the next sample.”
The science team is preparing to quickly collect a sample from the hard layer of Snow White and deliver it to one of the eight ovens of Phoenix’s Thermal and Evolved-Gas Analyzer (TEGA). Doors to the oven have been opened to receive the sample. TEGA will “bake and sniff” the samples to analyze the composition of the soil and ice.
On Wednesday the team also checked out the heater on TEGA is working properly, to verify that pressure sensors can be warmed enough to operate properly early in the Mars morning.
“For the next sample, we will be operating the instrument earlier in the morning than we have before,” said William Boynton of the University of Arizona, lead scientist for TEGA. “It will be almost the coldest part of the day, because we want to collect the sample cold and deliver it cold.”
On the day when Phoenix will deliver the next sample to TEGA, the team plans to have lander activities begin about three hours earlier than the usual start time of about 9 a.m. local solar time.
On Thursday, one set of imaging commands will check a northwestern portion of the horizon repeatedly during early afternoon to see whether any dust devils can be seen. This will be the first systematic check by Phoenix for dust devils. The Mars Rover Spirit was able to image sequences of dust devils in its location, south of Mars’ equator.
TEGA oven doors wide open. Credit: NASA/JPL-Caltech/University of Arizona/Texas A&M University
[/caption]
For the first time, the Phoenix lander stayed up all night. But there was no partying for the little lander, just hard work. Phoenix coordinated its schedule to work together with the Mars Reconnaissance Orbiter to make joint observations to study Mars’ atmosphere. More on that in a minute, but the other big news from the Phoenix lander is that the doors to the Thermal and Evolved Gas Analyzer (TEGA) oven successfully opened, and the device is now ready to accept a sample of icy soil. If you remember, way back in the beginning of the mission, on about Sol 8, the first time the science team relayed orders for the spring-loaded oven doors to open, the doors only opened partially and the team had to vibrate the oven to get the soil inside. But this time, the 10 cm (4 inch) doors stands wide open, and today Phoenix will perfect its techniques to quickly get the icy soil sample inside the oven before the ice sublimates.
Now, about those atmospheric observations: Phoenix used its weather station, stereo camera and conductivity probe to monitor changes in the lower atmosphere and ground surface at the same time MRO studied the atmosphere and ground from above. The orbiter flew repeatedly over Phoenix’s location last evening, so it was good timing for a coordinated effort.
“We are looking for patterns of movement and phase change,” said Michael Hecht, lead scientist for Phoenix’s Microscopy, Electrochemistry and Conductivity Analyzer, which includes the lander’s fork-like thermal and conductivity probe. “The probe is working great. We see some changes in soil electrical properties, which may be related to water, but we’re still chewing on the data.”
The probe was inserted into the soil Sunday for more than 24 hours of measurements coordinated with the atmosphere observations. One goal is to watch for time-of-day changes such as whether some water alters from ice phase to vapor phase and enters the atmosphere from the soil.
The Phoenix team’s plans also include commanding the lander to conduct additional testing of the techniques for collecting a sample of icy soil. When the team is confident about the collecting method, it plans to use Phoenix’s robotic arm to deliver an icy sample to an oven of TEGA.
The team wants to make sure their techniques will quickly bring the soil into the oven, as it’s possible the oven will only work for one more test. The vibrating done to get the soil into the oven for the previous test caused a short circuit that may happen again the next time the oven is activated. The short could be fatal to the oven, but of course, we’re all still holding out hope for a better case scenario.
OK, everyone: get out your funky 3-D glasses for a whole new look at Mars! We’ve seen the smooth plains of Meridiani from Opportunity in 3-D; we’ve gazed upon the rocky terrain of Gusev Crater from Spirit in more than two dimensions. But now it’s time to feast your eyes on Mars’ arctic tundra as its never been seen before: in super frozen 3-D from the Phoenix lander! The image above shows a color, stereoscopic 3D view of the Martian surface near the lander, and is one of Phoenix’s workplaces called “Wonderland.” But wait! There’s more…..
This 3-D view is from an image acquired by Phoenix’s Surface Stereo Imager on Sol 33, the 33rd Martian day of the mission (June 28, 2008). Phoenix’s solar panel is seen in the bottom right corner of the image.
Here’s a close up view of where all the action has been taking place recently: the trench called “Snow White.” The hole to the left of the trench, seen in the upper left of the image, is informally called “Burned Alive. This image was taken on Sol 22, but recently, Phoenix has scooped and rasped the area in an effort to get “shaved ice” samples.
Here’s a great touchy-feely 3-D image (don’t you just want to reach out and touch that rock?) The largest rock seen in this image is called “Midgard.” The edge of Phoenix’s deck is seen in the bottom right corner of the image.
The Japanese lunar mission SELENE (Selenological and Engineering Explorer), also known as “Kaguya” has imaged the “halo” left behind in the lunar surface from Apollo 15’s lunar module engine exhaust plume. This is the first time a mission after the Apollo Program has detected such a feature. Apollo 15 landed on the Moon in 1971 in a region called Mare Imbrium, and SELENE’s Terrain Camera (TC) is continuing to reconstruct a 3D view of the region in unprecedented high-resolution.
The Hadley Rille, at the foot of the Apennine Mountains encircling the Mare Imbrium where Apollo 15 landed (NASA/JAXA)
Apollo 15 touched down on the lunar surface on July 31st, 1971 with David Scott and James Irwin, to carry out 18.5 hours of lunar extra-vehicular activity. This was the first “J mission” where a greater emphasis was placed on scientific studies. After the lunar module blasted off from the Moon, the lunar astronauts looked back on the launch site to see a fresh “halo” had formed after the surface was exposed to the module’s engine exhaust plume. The NASA astronauts took before and after shots of the landing zone where a lightening of the surface is evident. This halo had not been observed since Apollo 15, until the high resolution Terrain Camera on board SELENE imaged the region.
Apollo 15 halo as observed by SELENE (JAXA)
The image (pictured left) processed by the SELENE mission instrument team appears to show a bright patch in the exact location of the Apollo 15 lunar module landing zone at the foot of the Apennine Mountains around the Mare Imbrium close to “Hadley Rille.” The Hadley Rille is a sinuous rille with a length of 80km and depth of 300m. A “sinuous rille” is a long, narrow, meandering depression in the lunar surface (much like a river basin, minus water). One of the primary mission objectives of Apollo 15 was to understand the origin of this rille. The most likely cause of Hadley Rille is lava flow during early development of the Moon. For the Apollo 15 astronauts, this region will have been an awesome sight, especially being at the base of the towering Apennine Mountains.
Comparison between 3D SELENE landscape and Apollo 15 photo (JAXA/NASA)
The TC instrument has been instrumental in creating 3D visualizations of the lunar surface. In the example left, a comparison of the TC reconstruction and an actual Apollo 15 photograph are compared. Although some of the detail is missing (as the individual rocks are below the 10 meter resolving power of the orbiting camera), the scenes are identical. The SELENE mission (launched in 2007) continues to generate a huge amount of 3D data, contributing to some of the most detailed maps of the lunar surface ever created.
The Phoenix Mars Lander successfully used a rasp on the end of its robotic arm to drill into the frozen soil on Mar’s arctic tundra. This effort loosened the icy material, which was then scraped up and collected in the lander’s scoop. Images and data sent from Phoenix early today indicated the shaved material in the scoop had changed slightly over time during the hours after it was collected, which is a sign that the material includes water ice. Water ice sublimates, or evaporates on Mars surface because of the low surface pressure on the Red Planet. It can exist just under the surface, however, protected by the soil.
The motorized rasp — located on the back of the lander’s robotic arm scoop — made two distinct holes in a trench informally named “Snow White.” The material loosened by the rasp was collected in the scoop and documented by the Robotic Arm Camera. The activity was a test of the rasping method of gathering an icy sample, in preparation for using that method in coming days to collect a sample for analysis in an oven of Phoenix’s Thermal and Evolved-Gas Analyzer (TEGA).
“This was a trial that went really well,” said Richard Morris, a Phoenix science team member from NASA’s Johnson Space Center, Houston. “While the putative ice sublimed out of the shavings over several hours, this shows us there will be a good chance ice will remain in a sample for delivery” to Phoenix’s laboratory ovens.
The motorized rasp bit extends from the back of the scoop on the end of Phoenix’s 2.35-meter-long (7.7-foot-long) robotic arm. The tool works just a rasp for woodworking, which coarsely files or shaves material.
‘While Phoenix was in development, we added the rasp to the robotic arm design specifically to grind into very hard surface ice,’ said Barry Goldstein, Phoenix project manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. ‘This is the exactly the situation we find we are facing on Mars, so we believe we have the right tool for the job. Honeybee Robotics in New York City did a heroic job of designing and delivering the rasp on a very short schedule.'”
The past few days, Phoenix used its robotic arm to clear the top layer of dirt from a trench it dug called Snow White. On Tuesday, Phoenix used the rasp to dig into two spots at the bottom of the trench.
Mission scientists have been working on techniques to quickly obtain the sample and then deliver it to the TEGA before too much ice has sublimated away. The TEGA test will “bake” the soil, releaseing gases present to help sciencists learn more about the ice’s composition.
Today, (Wednesday) Phoenix will be commanded to continue scraping and enlarging the “Snow White” trench and to conduct another series of rasp tests. The lander’s cameras will again be used to monitor the sample in the scoop after its collection.
It’s not that the Phoenix lander’s mission to Mars is over – not by a longshot. But Phoenix did stick a fork in it. The “fork” is a four-pronged thermal and electrical conductivity probe that Phoenix poked into the Martian soil for the first time. The probe tool can help the science team assess how easily heat and electricity move through the soil from one spike to another. These measurements can provide information about frozen or unfrozen water in the soil. The probe is mounted on the “knuckle” of Phoenix’s Robotic Arm. The probe has already been used for assessing water vapor in the atmosphere when it is held above the ground.
The image above is a series of six images, taken on July 8, 2008, during the Phoenix mission’s 43rd Martian day, or sol, since landing. The insertion visible from the shadows cast on the ground on that sol was a validation test of the procedure. The spikes on the probe are about 1.5 centimeters or half an inch long.
Phoenix also tried out another instrument: atomic force microscope. This Swiss-made microscope builds an image of the surface of a particle by sensing it with a sharp tip at the end of a spring, all micro- fabricated from a sliver of silicon. The sensor rides up and down following the contour of the surface, providing information about the target’s shape.
“The same day we first touched a target with the thermal and electrical conductivity probe, we first touched another target with a needle about threeorders of magnitude smaller — one of the tips of our atomic force microscope,”said Michael Hecht of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., lead
scientist for the suite of instruments on Phoenix that includes both the conductivity probe and the microscopy station.
The atomic force microscope can provide details of soil-particle shapes as small as about 100 nanometers, less than one-hundredth the width of a human hair. This is about 20 times smaller than what can be resolved with Phoenix’s opticalmicroscope, which has provided much higher-magnification imaging than anythingseen on Mars previously.
The team for the robotic arm is still working out the best way to get samples of ice from the trench dug earlier called “Snow White,” and be able to transfer the samples quickly into the Thermal and Evolved-Gas Analyzer (TEGA) which heats samples and identifies vapors from them.
Scientists have yet to release any information about the second test from the Wet Chemistry Lab. They are still analyzing the results.
Remember the amazing image that the HiRISE Camera on the Mars Reconnaissance Orbiter captured of the Phoenix Lander as it descended to Mars’ surface via parachute back on May 25? Well, the HiRISE scientists have done a little more processing of the image, and have turned up an additional detail they didn’t see at first: Phoenix’s heat shield. The heat shield, which had been jettisons just after parachute deployment, can be seen falling toward the surface. You have to look really, really close to see it. But that’s what these HiRISE folks do. It was incredible that they found the lander with the parachute in the image (go see the big, huge image they had to hunt for it HERE) and these guys get the eagle eyes of the year award for finding the heat shield.
HiRISE made history by taking the first image of a spacecraft as it descended toward the surface of another planetary body. Here’s the image again:
The image shows NASA’s Phoenix Mars Lander when the spacecraft was still tucked inside its aeroshell, suspended from its parachute, at 4:36 p.m. Pacific Daylight Time on landing day. Although Phoenix appears to be descending into an impressive impact crater, it actually landed 20 kilometers, or 12 miles, away.
Mars Reconnaissance Orbiter was about 760 kilometers, or 475 miles, away when it pointed the HiRISE camera obliquely toward the descending Phoenix lander. The camera viewed through the hazy Martian atmosphere at an angle 26 degrees above the horizon when it took the image. The 10-meter, or 30-foot, wide parachute was fully inflated. Even the lines connecting the parachute and aeroshell are visible, appearing bright against the darker, but fully illuminated Martian surface.
In further analyzing the image, the HiRISE team discovered a small, dark dot located below the lander.
Phoenix was equipped with a heat shield that protected the lander from burning up when it entered Mars’ atmosphere and quickly decelerated because of friction. Phoenix discarded its heat shield after it deployed its parachute.
“Given the timing of the image and of the release of the heat shield, as well as the size and the darkness of the spot compared to any other dark spot in the vicinity, we conclude that HiRISE also captured Phoenix’s heat shield in freefall,” said HiRISE principal investigator Alfred McEwen.
The multigigabyte HiRISE image also includes a portion recorded by red, blue-green and infrared detectors, and scientists have processed that color part of the image.
HiRISE’s color bands missed the Phoenix spacecraft but do show frost or ice in the bowl of the relatively recent, 10-kilometer (6-mile) wide impact crater unofficially called “Heimdall.” The frost shows up as blue in the false-color HiRISE data, and is visible on the right wall within the crater.
The HiRISE camera doesn’t distinguish between carbon dioxide frost and water frost, but another instrument called CRISM on the Mars Reconnaissance Orbiter could.
If humans ever build a city on Mars, perhaps (in its retirement) the Phoenix Lander can apply for a job with the city’s public works department to scrape ice off sidewalks. Phoenix has been trying to dig down deeper into the “Snow White” trench and has been digging, scooping and scraping the ice layer that earlier soil scooping exposed. The robotic arm team is working to get an icy sample into the Robotic Arm scoop for delivery to the Thermal and Evolved Gas Analyzer (TEGA). Ray Arvidson of the Phoenix team, known as the “dig czar,” said the hard Martian surface that Phoenix has reached is proving to be a difficult target, and compared the process to scraping a sidewalk. “We have three tools on the scoop to help access ice and icy soil,” Arvidson said. “We can scoop material with the backhoe using the front titanium blade; we can scrape the surface with the tungsten carbide secondary blade on the bottom of the scoop; and we can use a high-speed rasp that comes out of a slot at the back of the scoop.”
“We expected ice and icy soil to be very strong because of the cold temperatures. It certainly looks like this is the case and we are getting ready to use the rasp to generate the fine icy soil and ice particles needed for delivery to TEGA,” he said.
Scraping action produced piles of scrapings at the bottom of a trench on Monday, but did not get the material into its scoop, evidenced from images returned to Earth by the lander. The piles of scrapings produced were smaller than previous piles dug by Phoenix, which made it difficult to collect the material into the Robotic Arm scoop.
“It’s like trying to pick up dust with a dustpan, but without a broom,” said Richard Volpe, an engineer from NASA’s Jet Propulsion Laboratory, Pasadena, Calif., on Phoenix’s Robotic Arm team.
The mission teams are now focusing on use of the motorized rasp within the Robotic Arm scoop to access the hard icy soil and ice deposits. They are conducting tests on Phoenix’s engineering model in the Payload Interoperability Testbed in Tucson to determine the optimum ways to rasp the hard surfaces and acquire the particulate material produced during the rasping. The testbed work and tests on Mars will help the team determine the best way to collect a sample of Martian ice for delivery to TEGA.
The Phoenix team also continues to analyze results from the Wet Chemistry Lab, as a sample was delivered to the lab on July 6. Results should be forthcoming.
