EPOXI mission patch. Credit: University of Maryland
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The re-purposed Deep Impact spacecraft will make one final flyby of Earth on Sunday June 27, 2010, getting a gravity assist to help propel the spacecraft towards a meetup with comet Hartley 2 this fall. The spacecraft bus that brought the Deep Impact “impactor” to comet Tempel 1 in July of 2005 has been put back to work double time where two new missions share the same spacecraft. This is the fifth time this spacecraft has flown by Earth, and at the time of closest approach on Sunday, it will be about 30,400 kilometers (18,900 miles) above the South Atlantic.
“The speed and orbital track of the spacecraft can be changed by changing aspects of its flyby of Earth, such as how close it comes to the planet,” said University of Maryland astronomer Michael A’Hearn, principal investigator for both the new EPOXI mission and its predecessor mission, Deep Impact.
The combined operation EPOXI is a combo-acronym of the two separate missions. The Deep Impact Extended Investigation (DIXI) of comets will observe comet 103P/Hartley 2 during a close flyby in November 2010. The other half of the dynamic duo, called the Extrasolar Planet Observation and Characterization (EPOCh) which is observing stars already known to have transiting giant planets.
“There is always some gravity boost at a flyby and in some cases, like this one, it is the main reason for a flyby. The last Earth flyby was used primarily to change the tilt of the spacecraft’s orbit to match that of comet Hartley 2, and we are using Sunday’s flyby to also change the shape of the orbit to get us to the comet,” said A’Hearn.
The Deep Impact mission smashed a companion probe into comet Tempel 1 on July 4, 2005 to reveal the inner material of a comet.
“Earth is a great place to pick up orbital velocity,” said Tim Larson, the EPOXI project manager from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “This flyby will give our spacecraft a 1.5-kilometer-per-second [3,470 mph] boost, setting us up to get up close and personal with comet Hartley 2.”
During a previous flyby of Earth, the mission team has used the spacecraft’s instruments to find evidence of water on the Moon and to study light reflected from Earth as a template that scientists eventually may be able be use to identify Earth-like planets around other stars.
One year ago today, the Lunar Reconnaissance Orbiter (LRO) officially reached orbit about the Moon, and in the past 12 months has gathered more digital information than any previous planetary mission in history. NASA says that maps and datasets collected by LRO’s state-of-the-art instruments will form the foundation for all future lunar exploration plans, as well as be critical to scientists working to better understand the moon and its environment. To celebrate one year in orbit, here are ten great observations made by LRO.
LRO's Diviner instrument found the coldest place in the solar system. Credit: NASA/Goddard/University of California, Los Angeles
1. Coldest Place in the Solar System.
If you think Pluto, a KBO, or the farthest reaches of our solar system are cold, a location closer to Earth is actually colder. Diviner, LRO’s temperature instrument, found a place in the floor of the moon’s Hermite Crater that was detected to be -415 degrees Fahrenheit (-248 Celsius) making it the coldest temperature measured anywhere in the solar system. For comparison, scientists believe that Pluto’s surface only gets down to about -300 degrees Fahrenheit (-184 Celsius). Extremely cold regions similar to the one in Hermite Crater were found at the bottoms of several permanently shaded craters at the lunar south pole and were measured in the depths of winter night.
Enlargement of area surrounding Apollo 11 landing site. Credit: NASA/GSFC/Arizona State University
2. Where Humans Have Walked on the Moon
LRO’s views of the Apollo landing sites are nothing short of stunning, not to mention exciting. Above is LRO’s latest looks at the Apollo 11 landing site, which clearly shows where the descent stage (about 12 feet in diameter) was left behind as well as the astronauts’ tracks and the various equipment they deployed. This LRO data has important scientific value, as it provides context for the returned Apollo samples. Beyond their use for science, the images of all six manned landing sites observed by LRO provide a reminder of NASA’s proud legacy of exploration and a note of inspiration about what humans are capable of in the future.
A pit on the Moon. Credit: NASA/Goddard/Arizona State University
3. Caves on the Moon
What could be more exciting than finding a cave on the Moon, a potential future lunar habitat for human explorers? LRO has now collected the most detailed images yet of at least two lunar pits, quite literally giant holes in the moon. Scientists believe these holes are actually skylights that form when the ceiling of a subterranean lava tube collapses, possibly due to a meteorite impact punching its way through. One of these skylights, the Marius Hills pit, was observed multiple times by the Japanese SELENE/Kaguya research team. With a diameter of about 213 feet (65 meters) and an estimated depth of 260 to 290 feet (80 to 88 meters) it’s a pit big enough to fit the White House completely inside. The image featured here is the Mare Ingenii pit. This hole is almost twice the size of the one in the Marius Hills and most surprisingly is found in an area with relatively few volcanic features.
The Russian Lunokhod rover was imaged by LRO. Credit: NASA/Goddard/Arizona State University
4. Finding Missing Spacecraft
Lunokhod 1 was the name of a Russian robotic rover that landed on the moon in 1970 and navigated about 6 miles (10 km) of the lunar surface over 10 months before it lost contact in September 1971. Scientists were unsure of the rover’s whereabouts, though at least one team of researchers were searching for it, hoping to bounce a laser off of its retroreflector mirrors. This past March however, the LROC team announced they had spotted it, miles from the location the laser team had been searching. Using the info provided by LRO, a laser pulse was sent to Lunokhod 1 and contact was made with the rover for the first time in nearly four decades. Not only did Lunokhod 1’s retroreflector return a signal, but it returned one that was about five times better than those that have routinely been returned by Lunokhod 2’s mirrors over the years.
The Apollo 14 crew came close to seeing the rim of Cone Crater, but not quite. Credit: NASA/Goddard/Arizona State University
5. Apollo 14’s Near Miss of Seeing Cone Crater.
When the Apollo 14 crew of Alan Shepard and Edgar Mitchell walked across their landing site at Fra Maura, they hoped to be able to gather samples from the rim of Cone Crater. But they didn’t ever find the rim, and without a roadmap or guideposts along the way to help them find it, (and also they didn’t have the benefit of riding on the lunar rover so had to walk the entire time). They walked nearly a mile (1400 meters) and the steep incline of the crater rim made the climb difficult, raising the astronaut’s heart rates. Plus the tight schedule of the activity resulted in mission control ordering them to gather whatever samples they could and return to the landing module. They never reached the edge of the crater. Though geologists say it did not greatly affect the success of the scientific goal, the astronauts were personally disappointed in failing to make it to the top. Images from LRO now show precisely just how far the astronauts traveled and how close they came to reaching the crater, their tracks ending only about 100 feet (30 meters) from the rim!
The rim of Cabeus Crater. Credit: NASA/Goddard/Arizona State University
6. Mountains on the Moon.
On the Earth, we are taught that mountains form over millions of years, the result of gradual shifting and colliding plates. On the moon however, the situation is quite different. Even the largest lunar mountains were formed in minutes or less as asteroids and comets slammed into the surface at tremendous velocities, displacing and uplifting enough crust to create peaks that easily rival those found on Earth. On a few occasions in the past year, NASA has tilted the angle of LRO to do calibrations and other tests. In such cases the camera has the opportunity to gather oblique images of the lunar surface like the one featured here of Cabeus Crater providing a dramatic view of the moon’s mountainous terrain. Cabeus Crater is located near the lunar south pole and contains the site of the LCROSS mission’s impact. Early measurements by several instruments on LRO were used to guide the decision to send LCROSS to Cabeus. During the LCROSS impact LRO was carefully positioned to observe both the gas cloud generated in the impact, as well as the heating at the impact site.
Lunar rilles. Image Credit: NASA/JHUAPL/LSI
7. Lunar Rilles: Mysterious Channels on the Moon
Rilles are long, narrow depressions on the lunar surface that look like river channels. Some are straight, some curve, and others, like the ones highlighted here, are called “sinuous” rilles and have strong meanders that twist and turn across the moon. Rilles are especially visible in radar imagery, like that gathered by LRO’s Mini-RF instrument. The formation of lunar rilles is not well understood. It is believed there may be many different formation mechanisms including ancient magma flows and the collapse of subterranean lava tubes. Imagery from LRO will help researchers to better understand these mysterious “river-like” lunar features.
Areas of constant sunlight on the Moon's south pole. Image Credit: NASA/Goddard
8. Areas of Near Constant Sunlight at the South Pole
One of the most vital resources LRO is searching for on the moon is solar illumination. Light from the sun provides both warmth and a source of energy, two critical constraints to exploration efforts. The moon’s axis is only slightly tilted so there are areas in high elevations at its poles that remain almost constantly exposed to the sun. Using LRO’s precise measurements of topography scientists have been able to map illumination in detail, finding some areas with up to 96% solar visibility. Such sites would have continuous sun for approximately 243 days a year and never have a period of total darkness for more than 24 hours.
With Moon Zoo, you can count craters and boulders on the Moon to help lunar scientists. Credit: NASA/Goddard/Arizona State University
9. Moon Zoo lets you Help Lunar Scientists.
The latest Citizen Science project from the Zooniverse, Moon Zoo uses about 70,000 high resolution images gathered by LRO, and in these images are details as small as 50 centimeters (20 inches) across. ‘Zooites’ are asked to categorize craters, boulders and more, including lava channels and later, comparing recent LRO images to ones taken years ago by other orbiting spacecraft.
The first tasks are counting craters and boulders. By comparing and analyzing these feature counts across different regions as well as other places like the Earth and Mars, Zooites can help scientists gain a better understanding of our solar system’s natural history.
The Moon's far side -- the part we never see from Earth. Credit: NASA/Goddard
10. Getting a Good Look at the Far Side.
Tidal forces between the moon and the Earth have slowed the Moon’s rotation so that one side of the moon always faces toward our planet. Though sometimes improperly referred to as the “dark side of the moon,” it should correctly be referred to as the “far side of the moon” since it receives just as much sunlight as the side that faces us. The dark side of the moon should refer to whatever hemisphere isn’t lit at a given time. Though several spacecraft have imaged the far side of the moon since then, LRO is providing new details about the entire half of the moon that is obscured from Earth. The lunar far side is rougher and has many more craters than the near side, so quite a few of the most fascinating lunar features are located there, including one of the largest known impact craters in the solar system, the South Pole-Aitken Basin. The image highlighted here shows the moon’s topography from LRO’s LOLA instruments with the highest elevations up above 20,000 feet in red and the lowest areas down below -20,000 feet in blue.
We spent 5 episodes telling the story of astronomy so far, how we got from the work of the Babylonians to the modern discoveries made in the last decade. But now we want to look forward, studying the current space missions and experiments to uncover the mysteries that astronomers hope to solve.
Artist concept of Kepler in space. Credit: NASA/JPL
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The Kepler spacecraft has found over 750 candidates for extrasolar planets, and that is just from data collected in the first 43 days of the spacecraft’s observations. “This is the biggest release of candidate planets that has ever happened,” said William Borucki, Kepler’s lead scientist. “The number of candidate planets is actually greater than all the planets that have been discovered in the last 15 years.”
This is an astounding amount of potential exoplanets from data taken during such a short period of time, however Borucki added that they expect only about 50% of these candidates to actually turn out to be planets, as some may be eclipsing binary stars or other artifacts in the data. But still, even half would be the biggest group discovery of exoplanets ever.
And the exciting part is that 706 targets from this first data set have viable exoplanet candidates with sizes from as small as Earth to around the size of Jupiter. The team says the majority have radii less than half that of Jupiter.
The Kepler team has found so many candidates, they are sharing. They will keep the top 400 candidates to verify and confirm with observations using other telescopes – with observations done by Kepler team members. And today they have released the other 350 candidates, including five potential multiple planet systems.
However, some astronomers are upset about this and think the Kepler team should release all of their findings from the first year, as is typically done with NASA data.
Kepler launched on March 6, 2009, and has been on the hunt for exoplanets. Of course, the holy grail is finding an Earth-like or Earth-sized planet, especially those in the habitable zone of stars where liquid water and possibly life might exist. In the spring of 2009 the Kepler Mission conducted high precision photometry on nearly 156,000 stars to detect the frequency and characteristics of small exoplanets. Kepler studied an area in the constellation Cygnus, looking for the small changes in light that would signal a planet passing in front of its star.
But it takes time to verify candidates and find out if they are actually exoplanets. Usually, confirming the transit of an extrasolar planet requires observations of three different transits. While NASA’s policy requires astronomers to release their data from NASA instruments in a year, the Kepler team has worked out an agreement with the space agency so they can keep a certain portion of their data until they actually have time to verify this huge amount of exoplanet data. Between launch delays of other telescopes, cloudy nights for Earth based telescopes, and viewing a part of the sky that is only visible from the ground from April until September, they haven’t had the observing time they needed to check out all their planet candidates. The extension of the deadline gives the Kepler team the time to make sure they have gone through and found all the false positives and other potential misinterpretations of the Kepler data.
Dennis Overbye in the New York Times has written an article that delves more deeply into this little controversy. What is propriety data, and what is public? It’s a tough argument either way: scientists who have put years of their life into building a spacecraft should have the time they need to verify their data. But others feel the science should be open and available, and a policy is a policy: the deadline for releasing the data is here.
Whatever your feelings on open or closed data (and the Kepler team is only getting an extra six months on just part of their data, by the way), you have to be impressed with the quantity of potential exoplanet finds. And Kepler still has at least two years left of observations.
The composite image from 11 images, each with 5 sec exposure, spaced by 35-50 sec. The magnitude of Hayabusa is estimated to be 21 mag. Credit: Subaru Telescope Team
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The world watched and waited for the Hayabusa spacecraft to make its return to Earth on June 13, 2010 and the people of Japan — who built and launched the little spacecraft that could (and did!) — were especially hopeful in watching and waiting. Japan’s Subaru Telescope (although located on Mauna Kea in Hawaii) turned its expectant eyes towards Hayabusa and captured the spacecraft’s flight between the Moon and Earth in 11 different images.
A note from the Subaru Telescope team:
During the busy time preparing the observations, Doctor Masafumi Yagi and his team managed to maneuver the telescope just in time to catch Hayabusa before it disappeared down south in the twilight sky. At that time, Hayabusa was a little less than half way between Moon and Earth. Five seconds exposures, each spaced by 35 – 50 seconds in the V filter with Suprime Cam, it showed up in clear trace at the position expected to be. Brightness is estimated to be only 21 magnitudes. At this level, one can see a background galaxy clearly.
We are waiting to hear more from the project team at ISAS/JAXA. In the meantime, congratulations to all who are involved in this unprecedented endeavor.
And here are some images of the recovery teams who picked up the sample return canister in the Woomera Prohibited Area in Australia. The canister will be taken to Japan and opened in a few weeks, or perhaps months, after rigorous testing. Only then will we find out if any asteroid samples made it in the canister for the ride back to Earth.
Recovery team makes sure all is safe with the sample return canister. Credit: JAXAThe recovery team handles the heat sheild for the Hayabusa sample return capsule. Credit: JAXA, Hayabusa Twitter feed.JAXA's Hayabusa space capsule is transported inside a box to a clean room inside the Instrumentation Building at the Woomera Test Range, South Australia. Credit: Australian Science Media Centre
Hayabusa's sample return cannister and parachute on the ground in the Australian outback. Credit: JAXA
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Scientists from Japan were given the go-ahead to retrieve the sample return capsule from the Hayabusa spacecraft, which is hoped to contain the first piece of asteroid ever brought to Earth, perhaps providing insight into the origins of asteroids – and our universe. The capsule was ejected three hours before reaching Earth, and the sample canister descended through Earth’s atmosphere, preceding the spacecraft which broke up in spectacular fashion (click here to see the video) over the Australian Outback. The capsule lay in the Woomera Prohibited Area until morning when Aboriginal elders deemed it had not landed in any indigenous sacred sites, giving the OK for the scientists to retrieve it.
The insulated and cushioned re-entry capsule, 40 cm in diameter and 25 cm deep has a mass of about 20 kg. The capsule had a convex nose covered with a 3 cm thick ablative heat shield to protect the samples from the high velocity (~13 km/s) re-entry.
Apparently, it landed right on target. The director of the Woomera test range, Doug Gerrie, said the probe had completed a textbook landing in the South Australian desert. “They landed it exactly where they nominated they would. Hayabusa's heat shield was also recovered from the Australian outback. Credit: JAXA
The capsule will remain sealed until it arrives at the JAXA facility near Tokyo, and may remain unopened for weeks as it undergoes testing.
The mission launched in 2003, and endured a series of technical glitches over its five-billion-kilometer (three-billion-mile) journey to the asteroid Itokawa and back. A large solar flare in late 2003 “injured” the solar panels, providing less power to Hayabusa’s ion engines, delaying the rendezvous with the asteroid. Then, as the spacecraft approached Itokawa, Hayabusa lost the use of its Y-axis reaction wheel. While it flew near the asteroid and sent back data, scientists and engineers aren’t sure if the spacecraft was successful in obtaining samples, as while it appears Hayabusa landed briefly, it is not certain the “bullets” fired to stir up dust for the container to capture. The return to Earth was delayed by three years from more thruster and navigational failures, but the JAXA team nursed and coaxed the spacecraft back home to a spectacular return. There was concern that the parachute batteries may be been depleted due to the extra time it took to get back to Earth, but obviously they worked quite well.
Japan’s little spacecraft that could returned to Earth, putting on quite a show over the Australian outback, making a fiery reentry. Hayabusa returned around 10 a.m. EDT (1400 GMT) in the Woomera Prohibited Area of South Australia. In the video you’ll see a little speck of light ahead of the falling debris: that’s the sample return canister with, hopefully, some precious goods aboard – samples from asteroid Itokawa. The canister separated about three hours before reaching Earth, and returned to Earth via parachute. The canister has been recovered, and will be taken to Japan where scientists will open it to find out if there is anything inside.
The return was monitored scientists from around the world, including a NASA crew on aboard a DC-8 airplane who took the video footage. Continue reading “Hayabusa Returns!”
Mars500 crew just seconds before ingressing their module for a 520 day stay in June 2010. Credit: ESA
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Six men from Europe, Russia and China embarked on a 520-day mock mission to Mars, heading out to a crew module in a warehouse in Moscow and locking the hatches behind them today. The mission runs from June 2010 to November 2011, and like a real Mars mission, the crew will live and work like astronauts, eating special food and exercising the same way as crews aboard the International Space Station. Additionally their communications with their mission control and anyone else from the rest of the world will have a delay of up to 40 minutes.
A joint project between the Russian space agency and ESA, officials said the mood was serious, intense but very determined in the Mars500 facility at the Institute of Biomedical Problems in Moscow as the crew talked to the press and then walked into the modules.
Diego Urbina and Romain Charles from Europe, Sukhrob Kamolov, Alexey Sitev, Alexandr Smoleevskiy and Mikhail Sinelnikov from Russia and Wang Yue from China will have a mission that is as ‘real’ as possible. Their mission is to ‘fly to Mars’ in 250 days, divide in two groups, ‘land on and explore Mars’ for a month and ‘return to Earth’ in 230 days, in their special facility imitating an interplanetary spacecraft, lander and Martian terrain. The Mars 500 facility. Credit: ESA
“It will be trying for all of us. We cannot see our family, we cannot see our friends, but I think it is all a glorious time in our lives,” said Chinese participant Wang Yue, 27, ahead of the experiment.
In addition to evaluating many new technologies, Mars500 will test of human endurance and psychological issues of being confined in a small space and being away from family and friends and a normal Earth-life.
The crew will be keeping online diaries and provide video updates to ESA’s Mars500 site.
What would it be like to approach Mars in a spacecraft? In one of the coolest movies ever, we now know! Using the the Visual Monitoring Camera (VMC) on board Mars Express, science teams put together 600 individual still images to create a movie of descending towards and then moving away from Mars. It shows the spacecraft’s slow descent from high above the planet, speeding up as closest approach is passed and then slowing down again as the distance increases. Continue reading “Mars Webcam Provides Astronaut-like View of Red Planet”
Artist impression of Voyager. Image credit: NASA/JPL
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In early May 2010, the 33-year-old Voyager 2 spacecraft experienced an anomaly where the data it returned to Earth was unreadable. Engineers diagnosed the problem as a flip of a bit in the memory in the flight data system computer that packages data to transmit back to Earth, and were able to successfully reset the computer. On May 23, Voyager 2 sent back data that was again formatted properly, but the teams wanted to check out all the systems on the spacecraft to make sure everything was working properly. We checked in with Dr. Ed Stone, former director of JPL and the project scientist for the Voyager project since 1972 to get the latest news on how Voyager 2’s checkout is progressing.
“The science teams have confirmed that Voyager 2 is again transmitting science data in the expected format and the instruments are fully functional,” Stone said via email. “The only remaining action is to reset the clock in the spacecraft’s data system that lost time while the memory bit was in the wrong state. The reset commands will be sent to the Voyager 2 in the next two weeks.”
The flipped or bad bit in the flight data system was likely caused by a cosmic ray that slipped by the radiation protection on the spacecraft. Since the computer stores information in ones and zeroes, a cosmic ray hit can change the value of a memory bit. The concern was that the flipped bit took place in an important location that could have a serious effect on the spacecraft, but fortunately, the problem was solved “easily.”
I say easily in quotes because of the complexities of diagnosing and fixing a spacecraft at such great distances. Since Voyager 2 is about 13.8 billion kilometers, or 8.6 billion miles, from Earth, it takes nearly 13 hours for signals to reach the spacecraft and nearly 13 hours for signals to come down to NASA’s Deep Space Network on Earth.
Hats off to the scientists and engineers at JPL for their efforts and dedication so we all can continue to follow Voyager’s continuing journey to interstellar space.
