Astronauts aboard space shuttle Atlantis are preparing to return to Earth after an ambitious and risky mission to re-fit the Hubble telescope.

There are two chances to land on Friday: one at 1500 BST (1000 EDT) and a second at 1639 BST (1139 EDT).

If bad weather scuppers either of those opportunities, the shuttle will try to land on Saturday in Florida or at Edwards Air Force Base, California.

The mission was intended to give a new lease of life to Hubble.

The orbiting observatory is regarded as one of the most important scientific tools ever built.

The fifth and final mission to service Hubble has been hailed as a great success.

Over five spacewalks, astronauts installed new instruments and thermal blankets, repaired two existing instruments, replaced gyroscopes and batteries.

The only disappointment was the failure to restore the high resolution channel (one of three) on Hubble’s main camera – the Advanced Camera for Surveys (ACS).

Cloudy skies and stormy weather could yet pose a problem for Friday’s landing attempts, Nasa has said.

The shuttle has enough supplies to remain in orbit until Monday.

The US space agency has cleared Atlantis for its fiery re-entry into Earth’s atmosphere following in-flight inspections of its heat shield by the crew.

The Hubble telescope was released from the shuttle’s robotic arm on Tuesday.

Atlantis ready to return to Earth

On a marathon spacewalk Sunday, two astronauts overcame repeated obstacles to make the second of two historic repairs to the Hubble Space Telescope.

One bolt that had to be extracted proved so stubborn that astronaut Michael Massimino resorted to brute force to rip it out of the telescope.

His efforts paid off. Hubble’s $166 million chemical analyzer, dead for nearly five years, came back to life after Massimino and a colleague rewired its electronics. The device makes a fingerprint of cosmic objects by separating light. It is good for finding black holes and examining the atmosphere of planets outside our solar system.

When Mission Control announced that the chemical analyzer had passed the “aliveness test” administered by engineers on Earth, the astronauts in space cheered.

“That sounds great,” Massimino said. “Thanks so much.”

Saturday, another team of astronauts revived a Hubble camera that broke two years ago.

Never before have astronauts tried to repair Hubble’s scientific instruments. Because those instruments weren’t designed for maintenance in space, working on them poses major challenges to astronauts wearing stiff, thick space gloves.

Sunday’s outing was the fourth of five spacewalks planned for the crew of space shuttle Atlantis, which is paying the last service call to the storied telescope. The seven Atlantis astronauts want to rejuvenate the Hubble to ensure it will last at least five more years.

The astronauts ran into a trio of unwelcome surprises during Sunday’s outing, which ran so long that they never got to their second scheduled chore, installation of insulation on the Hubble.

First, Massimino couldn’t undo a bolt holding a handrail in place — a major problem, because the handrail blocked access to the failed Space Telescope Imaging Spectrograph. Massimino yanked the handrail free after getting a go-ahead from Mission Control. Engineers estimated the task would take 60 pounds of force.

Then Massimino had trouble installing a device designed to grab 100-plus tiny screws he had to take out. The device was supposed to sit on the door to the spectrograph and keep the screws from floating into the Hubble’s workings.

Finally Massimino’s power screwdriver went dead, leading the exasperated astronaut to blurt out, “Oh, for Pete’s sake!” He had to break off working and travel to a distant toolbox to get a spare screwdriver.

The refrigerator-sized spectrograph has made major contributions to astronomy since it was added to Hubble in 1997. It doesn’t take photos but instead analyzes the composition of stars and other objects in the universe.

It detected black holes at the center of many galaxies and helped scientists do a definitive study of a star in the last stages of life. It was the first to analyze the atmosphere of a planet orbiting a star other than the sun.

Nearly every spacewalk made by the Hubble crew has run into unexpected difficulties. Thursday, spacewalker Andrew Feustel had to muscle another stuck bolt out of place. If he’d failed, a new camera would’ve had to return to Earth rather than being installed on the Hubble.

Friday, Massimino and spacewalking partner Michael Good had so much trouble replacing Hubble’s gyroscopes that they fell 90 minutes behind schedule.

The mission’s final spacewalk is scheduled for Monday. Feustel and partner John Grunsfeld will have to try to finish up the work that Massimino and Good didn’t have time for.

Hubble analyzer fixed, but not without headaches

A former Microsoft Corp. executive Charles Simonyi has safely returned from his 12-day “vacation” on the International Space Stati, It was the last trip on which nonastronauts could hitch a ride on the Russian Soyuz spacecraft.

Simonyi blasted off March 26 from Baikonur Cosmodrome in Kazakhstan with two crew members, Russian cosmonaut Gennadiy Padalka and American astronaut Michael Barratt. He took the only route available to space tourists: making a reservation for the Soyuz through US-based Space Adventures Ltd.

But the Soyuz is a one-time-use ship that can hold only three people. When the ISS crew goes up to six members from three, delivering the entire crew to the ISS will take two trips at capacity. There simply will be no seats for tourists, even those with $35 million to burn.

The seats that have been used by tourists will be taken by American astronauts. Last December, NASA signed a $141 million contract with the Russian Space Agency to send three ISS crew members on two Soyuz vehicles in 2011. And the number of seats booked by NASA probably will grow because the main transport used by US astronauts, the space shuttle, will be retired next year.

But space tourism companies are looking for ways to continue in business. Theoretically, they could purchase an entire Soyuz vehicle and send their clients to space even without docking at the ISS. This is what Space Adventurers intends to do. But such plans require building an extra Soyuz spacecraft, as all currently operating ships are contracted out for ISS expeditions.

“There is a potential to build [an extra] ship,” Aleksey Krasnov, the head of manned flights for the Russian Space Agency, said at a news conference. “But there are problems with this. This year we have a record number of flights – four – which means we need to launch four spacecrafts.

“It is necessary to consider industrial and production capacities as well as human resources when building the fifth ship,” Mr. Krasnov said. But he added that he hopes that Energiya, the company that constructs the Soyuz, will build a fifth ship.

Vitaliy Lopota, president and chief designer of Energiya, claims that it takes 2-1/2 to three years to build a spacecraft, which means tourist flights couldn’t resume until 2012-2013 at the earliest.

“But this project will require more financing,” Mr. Lapota was quoted as saying by the Russian news agency RIA Novosti. “The current conditions of financial markets are not allowing building an extra manned spacecraft.”

Private companies have started actively searching for cheaper options. A number of them are developing alternatives to Soyuz ships and carriers to get tourists to space. Competition is growing quickly.

The British firm Virgin Galactic is planning to send 500 people to space each year on its newly built SpaceShipTwo, carried by the rocket White Knight Two. It plans to send up its first tourist as soon as next year or in 2011, when all test flights are finished. A 2-1/2-hour space voyage will cost $200,000. Other companies such as Space Adventures and RocketShip Tours Inc. of Phoenix, are offering suborbital flights where tourists would fly about 37 to 68 miles high, experience weightlessness for five to 10 minutes, and return to Earth.

Space shuttle Discovery returned in good shape, after traveling more than 5 million miles and circling Earth 202 times. The 13-day flight — which ended as a Russian-launched crew was settling into the space station — was highlighted by the installation and unfurling of the station’s last pair of solar wings. The $300-million addition brought the orbiting outpost up to full power, a vital part of NASA’s plan to double the space station population and boost scientific research in a few months.

Mission Control delayed Discovery’s homecoming by about 90 minutes, or one orbit, because of windy, cloudy weather. But the wind shifted and conditions improved enough for the second and final landing opportunity of the day.

Shuttle Discovery lands in Florida – Los Angeles Times

NASA’s Kepler spacecraft blasted off from Kennedy Space Center in Florida on Friday on a three-year mission to find Earth’s twin, a Goldilocks planet where it’s neither too hot nor too cold, but just right for life to take hold.

The Delta II rocket, carrying the widest-field telescope ever put in space, lifted off the launch pad at Cape Canaveral at 10:49 p.m. Eastern time.

The launch vehicle headed downrange, gathering speed as its three stages ignited, one after the other, passing over the Caribbean island of Antigua and tracking stations in Australia before climbing into orbit.

Kepler will eventually settle down to scan tens of thousands of stars near the constellations Cygnus and Lyra in search of planets where water could exist on the surface in liquid form, a key condition for life as we know it.

“We have a feeling like we’re about to set sail across an ocean to discover a new world,” said project manager Jim Fanson of the Jet Propulsion Laboratory in La Cañada Flintridge. “It’s sort of the same feeling Columbus or Magellan must have had.”

The $590-million Kepler mission is jointly managed by JPL and NASA’s Ames Research Center in the Bay Area. The spacecraft carries a 15-foot-long telescope with a 55-inch mirror that can scrutinize a wide star field for the telltale dimming of starlight that occurs when a planet crosses in front of it, known as a transit.

Over the last decade, scientists have employed the same technique with ground-based telescopes to discover 340 planets circling other stars. But because the optics of ground-based instruments are compromised by atmospheric interference, most of the planets found so far are Jupiter-like gas giants that orbit so close to their parent stars that any life forms would be incinerated.

The orbiting Hubble Space Telescope, whose optics are not hampered by Earth’s atmosphere, was designed to see deeply but very narrowly.

Kepler’s field of view is 33,000 times wider than Hubble’s, or about the size of a human hand held up to the sky. The Cygnus-Lyra region near the plane of the Milky Way encompasses about 4.5 million stars. But most of those are too big or hot to allow a habitable zone close enough to the star for Kepler to see a transit.

The science team has selected about 150,000 sun-like stars for Kepler to analyze. Over time, Fanson said, the number will be winnowed down to about 100,000 in three classes: G-type stars, which are similar in size and age to the sun; K- and M-type stars, which are slightly smaller and cooler; and A- and F-class stars, which are somewhat bigger.

Earth is in the center of the habitable zone around the sun, but with stars of other classes, that zone would be closer to the star or farther out.

Kepler’s telescope is outfitted with a sophisticated camera that will stare unblinkingly at the star field. The whole area will be imaged every six seconds, then stored in 30-minute chunks.

Once a month, Kepler will do a pirouette in space to download its stored data, Fanson said.

The scientists expect to find hundreds of planets during the mission, scheduled to last more than three years. But even with the telescope’s wide field of vision, it will be no easy task for Kepler to find smaller, Earth-like planets. Scientists have calculated that the change in brightness caused by such a planet transiting its star will be only about 0.008%, or about 84 parts per million. On top of that, there is less than one chance in 100 that a planet circling a far-off star will be aligned in just the right way for Kepler to spot a transit.

A final complication is that not all dimming is caused by transits. Sunspots on the surface of a star are cooler areas linked to an increase in magnetic activity. They also cause the star’s light to dim. But Kepler scientists said they think they understand the signature of sunspots well enough to deal with that problem.

For a planet to become a candidate for the first Earth-type planet around another star, Kepler must measure at least three separate transits, scientists said. If the team is uncertain about some measurements, or simply wants more observing time, the mission could be extended to six years, NASA said.

Kepler blasts off in search of Earth-like planets

The four core buildings, totaling 506,317 ft² (47,038 m²), were built for and originally occupied by Silicon Graphics (SGI). The office space and corporate campus is located within a larger 26-acre (110,000 m2) site that contains Charleston Park, a 5-acre (20,000 m2) public park; improved access to Permanente Creek; and public trails that connect the corporate site to Shoreline Park and the Bay Trail. The project, launched in 1994 to reclaim a former industrial brownfield, was a creative collaboration between SGI, STUDIOS Architecture in San Francisco, SWA Group of San Francisco and Sausalito, and the Planning and Community Development Agency of the City of Mountain View. The objective was to develop in complementary fashion the privately-owned corporate headquarters and adjoining public greenspace. Key design decisions placed parking for nearly 2000 cars underground, enabling SWA to integrate the two open spaces with water features, shallow pools, fountains, pathways, and plazas. The project was completed in 1997. The ASLA noted in 1999 that the SGI project was a significant departure from typical corporate campuses, challenging conventional thinking about private and public space.

The former SGI facilities were leased by Google beginning in 2003. In June 2006, Google purchased some of Silicon Graphics’ properties, including the Googleplex, for $319 million.

Since the buildings are of relatively low height, the complex covers a large area. The interior of the headquarters is furnished with items like shade lamps and giant rubber balls. The lobby contains a piano and a projection of current live Google search queries. The facilities include a gym (Building 40), free laundry rooms (Buildings 40 and 42), two small swimming pools, a sand volleyball court, and eleven cafeterias of diverse selection. Google has even installed replicas of SpaceShipOne and a dinosaur skeleton.

In late 2006 and early 2007 the company installed a series of solar panels, capable of producing 1.6 megawatts of electricity. At the time, it was believed to be the largest corporate installation in the United States. About 30 percent of the Googleplex’s electricity needs will be fulfilled by this project, with the remainder being purchased. About one third of the panels will be in the form of “solar trees” mounted on poles above parking lots, with the remainder placed on rooftops.

The solar panel project went online on 18 June 2007. As of 21 June 2007 Google has installed over 90% of the 9,212 solar panels that comprise the 1.6 megawatt project.

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