PARIS -  ESA’s fourth Automated Transfer Vehicle, Albert Einstein, completed a flawless rendezvous with the International Space Station on 15 June when it docked smoothly with orbital outpost at 14:07 GMT (16:07 CEST). The Automated Transfer Vehicle (ATV) is now connected to the Space Station.

“Bravo Europe, bravo ESA, bravo ATV. Thank you Member States, thank you industry, thank you CNES, thank you Russian partner,” commented Jean-Jacques Dordain, Director General of ESA. 

“With the fourth ATV now ready to support and supply the Space Station with essential supplies and scientific experiments, ESA again proves itself to be a reliable partner in the international station upon which the future can be developed.” 

The 20-tonne ferry, the heaviest spacecraft ever launched by Europe, flew autonomously and docked with the 420-tonne complex with a precision of a few cm as both circled Earth at 28 000 km/h.

Albert Einstein nears ISS Photo Credit: NASA TV

“Such a gentle contact between a spacecraft the size of a double-decker bus and a Station 20 times larger is an amazing achievement, highlighting the impressive level of control achieved by this European space system developed by our industry under ESA’s direction,” said Thomas Reiter, ESA’s Director of Human Spaceflight and Operations. 

“These impressive technological capabilities will live on in the service module of NASA’s upcoming Orion crew vehicle.” 

The rendezvous and docking were performed autonomously by ATV’s own computers, closely monitored by flight controllers from ESA and France’s CNES space agency at the ATV Control Centre in Toulouse, France, and by Luca Parmitano and his crewmates on the Station. Like its predecessors, ATV-4 is much more than a simple supply vessel: it is a space tug, a tanker, a freighter and a temporary habitation module.

To compensate for the natural decay in altitude of the Station’s orbit caused by atmospheric drag, it is loaded with 2580 kg of propellant to perform regular reboosts. It can even move the entire space complex out of the path of hazardous space debris. ATV also provides attitude control when other spacecraft are approaching the Station. 

In its tanks, it carries 860 kg of propellant, 100 kg of oxygen and air, and 570 kg of drinking water, all to be pumped into the Station’s tanks. In its pressurised cargo module, it carries more than 1400 items packed into 141 bags, including 2480 kg of dry cargo such as scientific equipment, spare parts, food and clothes for the astronauts.

During its four months attached to the Station, ATV will provide 45 cubic metres of extra crew quarters. On previous missions, the addition was welcomed by the astronauts as “the quietest place in the Station” and was often the preferred area for working. 

At the end of its mission, scheduled for 28 October, ATV-4 will separate from the Station, packed with waste bags. The following day, it will be directed to burn up safely in the atmosphere during reentry over the South Pacific Ocean.

PASADENA, Calif. -- Researchers using NASA's Mars Reconnaissance Orbiter have found that temperatures in the Martian atmosphere regularly rise and fall not just once each day, but twice.

"We see a temperature maximum in the middle of the day, but we also see a temperature maximum a little after midnight," said Armin Kleinboehl of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who is the lead author of a new report on these findings.

Temperatures swing by as much as 58 degrees Fahrenheit (32 kelvins) in this odd, twice-a-day pattern, as detected by the orbiter's Mars Climate Sounder instrument.

The new set of Mars Climate Sounder observations sampled a range of times of day and night all over Mars. The observations found that the pattern is dominant globally and year-round. The report is being published in the journal Geophysical Research Letters.

Global oscillations of wind, temperature and pressure repeating each day or fraction of a day are called atmospheric tides. In contrast to ocean tides, they are driven by variation in heating between day and night. Earth has atmospheric tides, too, but the ones on Earth produce little temperature difference in the lower atmosphere away from the ground. On Mars, which has only about one percent as much atmosphere as Earth, they dominate short-term temperature variations throughout the atmosphere.

Tides that go up and down once per day are called "diurnal." The twice-a-day ones are called "semi-diurnal." The semi-diurnal pattern on Mars was first seen in the 1970s, but until now it had been thought to appear just in dusty seasons, related to sunlight warming dust in the atmosphere.

"We were surprised to find this strong twice-a-day structure in the temperatures of the non-dusty Mars atmosphere," Kleinboehl said. "While the diurnal tide as a dominant temperature response to the day-night cycle of solar heating on Mars has been known for decades, the discovery of a persistent semi-diurnal response even outside of major dust storms was quite unexpected, and caused us to wonder what drove this response."

He and his four co-authors found the answer in the water-ice clouds of Mars. The Martian atmosphere has water-ice clouds for most of the year. Clouds in the equatorial region between about 6 to 19 miles (10 to 30 kilometers) above the surface of Mars absorb infrared light emitted from the surface during daytime. These are relatively transparent clouds, like thin cirrus clouds on Earth. Still, the absorption by these clouds is enough to heat the middle atmosphere each day. The observed semi-diurnal temperature pattern, with its maximum temperature swings occurring away from the tropics, was also unexpected, but has been replicated in Mars climate models when the radiative effects of water-ice clouds are included.

"We think of Mars as a cold and dry world with little water, but there is actually more water vapor in the Martian atmosphere than in the upper layers of Earth's atmosphere," Kleinboehl said. "Water-ice clouds have been known to form in regions of cold temperatures, but the feedback of these clouds on the Mars temperature structure had not been appreciated. We know now that we will have to consider the cloud structure if we want to understand the Martian atmosphere. This is comparable to scientific studies concerning Earth's atmosphere, where we have to better understand clouds to estimate their influence on climate."

JPL, a division of the California Institute of Technology in Pasadena, provided the Mars Climate Sounder instrument and manages the Mars Reconnaissance Orbiter project for NASA's Science Mission Directorate, Washington.
 

PASADENA, Calif. -- NASA research indicates hunks of frozen carbon dioxide -- dry ice -- may glide down some Martian sand dunes on cushions of gas similar to miniature hovercraft, plowing furrows as they go.

Researchers deduced this process could explain one enigmatic class of gullies seen on Martian sand dunes by examining images from NASA's Mars Reconnaissance Orbiter (MRO) and performing experiments on sand dunes in Utah and California.

"I have always dreamed of going to Mars," said Serina Diniega, a planetary scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and lead author of a report published online by the journal Icarus. "Now I dream of snowboarding down a Martian sand dune on a block of dry ice."

The hillside grooves on Mars, called linear gullies, show relatively constant width -- up to a few yards, or meters, across -- with raised banks or levees along the sides. Unlike gullies caused by water flows on Earth and possibly on Mars, they do not have aprons of debris at the downhill end of the gully. Instead, many have pits at the downhill end.

Several types of downhill flow features have been observed on Mars. This image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter is an example of a type called "linear gullies." Image credit: NASA/JPL-Caltech/Univ. of Arizona

"In debris flows, you have water carrying sediment downhill, and the material eroded from the top is carried to the bottom and deposited as a fan-shaped apron," said Diniega. "In the linear gullies, you're not transporting material. You're carving out a groove, pushing material to the sides."

Images from MRO's High Resolution Imaging Science Experiment (HiRISE) camera show sand dunes with linear gullies covered by carbon-dioxide frost during the Martian winter. The location of the linear gullies is on dunes that spend the Martian winter covered by carbon-dioxide frost. By comparing before-and-after images from different seasons, researchers determined that the grooves are formed during early spring. Some images have even caught bright objects in the gullies.

Scientists theorize the bright objects are pieces of dry ice that have broken away from points higher on the slope. According to the new hypothesis, the pits could result from the blocks of dry ice completely sublimating away into carbon-dioxide gas after they have stopped traveling.

"Linear gullies don't look like gullies on Earth or other gullies on Mars, and this process wouldn't happen on Earth," said Diniega. "You don't get blocks of dry ice on Earth unless you go buy them."

That is exactly what report co-author Candice Hansen, of the Planetary Science Institute in Tucson, Ariz., did. Hansen has studied other effects of seasonal carbon-dioxide ice on Mars, such as spider-shaped features that result from explosive release of carbon-dioxide gas trapped beneath a sheet of dry ice as the underside of the sheet thaws in spring. She suspected a role for dry ice in forming linear gullies, so she bought some slabs of dry ice at a supermarket and slid them down sand dunes.

That day and in several later experiments, gaseous carbon dioxide from the thawing ice maintained a lubricating layer under the slab and also pushed sand aside into small levees as the slabs glided down even low-angle slopes.

The outdoor tests did not simulate Martian temperature and pressure, but calculations indicate the dry ice would act similarly in early Martian spring where the linear gullies form. Although water ice, too, can sublimate directly to gas under some Martian conditions, it would stay frozen at the temperatures at which these gullies form, the researchers calculate.

"MRO is showing that Mars is a very active planet," Hansen said. "Some of the processes we see on Mars are like processes on Earth, but this one is in the category of uniquely Martian."

Hansen also noted the process could be unique to the linear gullies described on Martian sand dunes.

"There are a variety of different types of features on Mars that sometimes get lumped together as 'gullies,' but they are formed by different processes," she said. "Just because this dry-ice hypothesis looks like a good explanation for one type doesn't mean it applies to others."

The University of Arizona Lunar and Planetary Laboratory operates the HiRISE camera, which was built by Ball Aerospace & Technologies Corp. of Boulder, Colo. JPL, a division of the California Institute of Technology in Pasadena, manages MRO for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems, Denver, built the orbiter. 

PARIS - Despite requests to take a "strategic pause" to re-evaluate its design, ESA officials are moving ahead with the design of its Ariane 6 booster which is intended to cement Europe's lead in the launch services market.

The controversy centers around the boosters solid propellant first stage. Many, including Europe’s Air & Space Academy, believe that mounting a cryogenic upper stage atop two solid rocket boosters is not a sound design and are urging ESA to take time to develop a "more powerful liquid fueled alternative". But ESA Launch Vehicle Director Antonio Fabrizi disagrees stating that the design "received the specific endorsement of ESA’s governments last November and cannot simply be set aside."

Ariane 6 shown with 2 and 4 solid rocket boosters Photo Credit: CNES

The current plan calls for freezing the design in July of this year and then beginning construction in late 2014. First flight will be in 2021 although several issues still need to be hammered out. These include the size of the payload fairing and the number of solid boosters that will be used (2 or 4). There is also the tedious process of deciding which nations get to build what components - the entire project is worth 4 billion euros so there will be a lot of fighting about who gets to build the big parts. In the mean time ESA is moving ahead with a 2 billion Euro upgrade to its existing Ariane V booster. This upgrade, intended to be complete by 2017 and known as the Ariane V ME, will increase the boosters lift by providing it with a reignitable upper stage upper stage. 

In defense of the solid booster configuration, Arianespace officials are quick to point out that there has never been a problem with the Atiane V Solid Rocket Boosters and that they are considered to be one of the most reliable components of the Ariane V stack. Also synergies between ESA's solid fuel Vega booster and the new Ariane 6 would benefit both projects. 

Currently, Arianespace considers itself to be hamstrung by the need to provide two satellites every two or three months for the Ariane V and yet remain within the vehicles performance range. Currently, customers have to wait until a compatible partner can be found for the launch.  The new Ariane 6 system will launch a single satellite at a time allowing for more flexibility and less wait time for the customers. Ariane 6 will be able to orbit payloads weighing as much as 6.5 tones making it competitive with most of the worlds planed commercial launch systems. 

Although Arianespace is currently the worlds leading launch services provider it realizes that the market is changing dramatically. SpaceX's  Falcon launch vehicle, along with China's Long March series of rockets, India's GSLV and PSLV boosters, Japan's H-2, and Ukraine's Zenit are all set to enter the commercial launch services market within the next few years. Combined with the company's traditional competitors, the American Atlas V and Delta IV, Russia's Proton, and Japan's H-2 , these factors threaten the company's leadership position in the market. As a result the company has decided to construct a new booster custom designed to fit the future market. The Ariane 6 has been under development since 2009. 

PASADENA - Stars have an alluring pull on planets, especially those in a class called hot Jupiters, which are gas giants that form farther from their stars before migrating inward and heating up.

Now, a new study using data from NASA's Kepler Space Telescope shows that hot Jupiters, despite their close-in orbits, are not regularly consumed by their stars. Instead, the planets remain in fairly stable orbits for billions of years, until the day comes when they may ultimately get eaten.

"Eventually, all hot Jupiters get closer and closer to their stars, but in this study we are showing that this process stops before the stars get too close," said Peter Plavchan of NASA's Exoplanet Science Institute at the California Institute of Technology, Pasadena, Calif. "The planets mostly stabilize once their orbits become circular, whipping around their stars every few days."

The study, published recently in the Astrophysical Journal, is the first to demonstrate how the hot Jupiter planets halt their inward march on stars. Gravitational, or tidal, forces of a star circularize and stabilize a planet's orbit; when its orbit finally become circular, the migration ceases.

"When only a few hot Jupiters were known, several models could explain the observations," said Jack Lissauer, a Kepler scientist at NASA's Ames Research Center, Moffet Field, Calif., not affiliated with the study. "But finding trends in populations of these planets shows that tides, in combination with gravitational forces by often unseen planetary and stellar companions, can bring these giant planets close to their host stars."

Hot Jupiters are giant balls of gas that resemble Jupiter in mass and composition. They don't begin life under the glare of a sun, but form in the chilly outer reaches, as Jupiter did in our solar system. Ultimately, the hot Jupiter planets head in toward their stars, a relatively rare process still poorly understood.

The new study answers questions about the end of the hot Jupiters' travels, revealing what put the brakes on their migration. Previously, there were a handful of theories explaining how this might occur. One theory proposed that the star's magnetic field prevented the planets from going any farther. When a star is young, a planet-forming disk of material surrounds it. The material falls into the star -- a process astronomers call accretion -- but when it hits the magnetic bubble around it, called the magnetosphere, the material travels up and around the bubble, landing on the star from the top and bottom. This bubble could be halting migrating planets, so the theory went.

Another theory held that the planets stopped marching forward when they hit the end of the dusty portion of the planet-forming disk.

"This theory basically said that the dust road a planet travels on ends before the planet falls all the way into the star," said co-author Chris Bilinski of the University of Arizona, Tucson. "A gap forms between the star and the inner edge of its dusty disk where the planets are thought to stop their migration."

And yet a third theory, the one the researchers found to be correct, proposed that a migrating planet stops once the star's tidal forces have completed their job of circularizing its orbit.

To test these and other scenarios, the scientists looked at 126 confirmed planets and more than 2,300 candidates. The majority of the candidates and some of the known planets were identified via NASA's Kepler mission. Kepler has found planets of all sizes and types, including rocky ones that orbit where temperatures are warm enough for liquid water.

The scientists looked at how the planets' distance from their stars varied depending on the mass of the star. It turns out that the various theories explaining what stops migrating planets differ in their predictions of how the mass of a star affects the orbit of the planet. The "tidal forces" theory predicted that the hot Jupiters of more massive stars would orbit farther out, on average.

The survey results matched the "tidal forces" theory and even showed more of a correlation between massive stars and farther-out orbits than predicted.

This may be the end of the road for the mystery of what halts migrating planets, but the journey itself still poses many questions. As gas giants voyage inward, it is thought that they sometimes kick smaller, rocky planets out of the way, and with them any chance of life evolving. Lucky for us, our Jupiter did not voyage toward the sun, and our Earth was left in peace. More studies like this one will help explain these and other secrets of planetary migration.

The technical paper is online at http://iopscience.iop.org/0004-637X/769/2/86/.

NASA Ames manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with JPL at the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes the Kepler science data. Kepler is NASA's 10th Discovery Mission and is funded by NASA's Science Mission Directorate at the agency's headquarters in Washington.

NASA's Exoplanet Science Institute at Caltech manages time allocation on the Keck telescope for NASA. JPL manages NASA's Exoplanet Exploration program office. Caltech manages JPL for NASA.