Expedition 28 Commander Andrey Borisenko and Flight Engineers Alexander Samokutyaev and Ron Garan landed their Soyuz TMA-21 spacecraft in Kazakhstan a few seconds before midnight EDT Friday, with an official landing time of 11:59:39 p.m. Thursday. Russian recovery teams were on hand to help the crew exit the Soyuz vehicle and adjust to gravity after 164 days in space.

The trio launched aboard the Soyuz TMA-21 spacecraft from the Baikonur Cosmodrome in Kazakhstan in April and spent 162 days living and working aboard the International Space Station.

Samokutyaev was at the controls of the spacecraft as it undocked at 8:38 p.m. Thursday from the Poisk docking port on the station's Zvezda service module.

The undocking marked the end of Expedition 28 and the start of Expedition 29 under the command of NASA astronaut Mike Fossum, who is scheduled to remain on the station with Flight Engineers Sergei Volkov and Satoshi Furukawa until November. Borisenko ceremonially handed command of the station over to Fossum on Wednesday. Fossum, Volkov and Furukawa arrived at the station aboard the Soyuz TMA-02M spacecraft in June.

NASA and its international partners have agreed to a tentative launch schedule with crew flights to the International Space Station resuming on Nov. 14. The Space Station Control Board, with representation from all partner agencies, set the schedule after hearing the Russian Federal Space Agency’s findings on the Aug. 24 loss of the Progress 44 cargo craft. The dates may be adjusted to reflect minor changes in vehicle processing timelines.

According to the current plan, the Soyuz 28 spacecraft, carrying NASA's Dan Burbank and Russia's Anatoly Ivanishin and Anton Shkaplerov, will launch Nov. 14 from the Baikonur Cosmodrome in Kazakhstan and arrive at the station on Nov. 16.

The Herschel infrared space observatory has discovered that galaxies do not always need to collide with each other to drive vigorous star birth. The finding overturns a long-held assumption and paints a more stately picture of how galaxies evolve.

Herschel is a European Space Agency mission with important contributions from NASA and NASA's Jet Propulsion Laboratory in Pasadena, Calif.

"Galaxy mergers play an important role in producing the most powerful starbursts today," said Lee Armus, a co-author of the new study from NASA's Herschel Science Center at the California Institute of Technology in Pasadena. "But in the early universe, when most galaxies contained a lot more gas, mergers were not the only way, or even the most common way, to make lots of stars at a rapid rate."

The new results are based on Herschel's observations of two patches of sky, each about one-third the size of the full moon.

It's like looking through a keyhole across the universe. Herschel has seen more than a thousand galaxies at a variety of distances from Earth, spanning 80 percent of the age of the cosmos.

These observations are unique because Herschel can obtain data at a wide range of infrared light and reveal a more complete picture of star birth than ever seen before.

The results appear in the journal Astronomy & Astrophysics. Read more at http://www.esa.int/SPECIALS/Herschel/SEM2Y40UDSG_0.html .

Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes and with important participation by NASA. NASA's Herschel Project Office is based at JPL. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at Caltech, supports the United States astronomical community. Caltech manages JPL for NASA.

Space Farm 7 is a celebration of NASA's space, science and exploration programs that both honors the agency's missions and features a contest, the grand prize winner of which will win four tickets to visit the Kennedy Space Center and dine with an astronaut.

Each of the seven participating farms planted corn mazes that feature designs celebrating NASA's achievements and each of the Space Farms are paired with the closest NASA center in order to highlight that region’s contribution to the agency. The farms are open to the public and feature NASA-related educational games and activities. This outreach project will expose participants to NASA's space exploration and other missions.

Sunspot 1283 erupted with another flare yesterday that peaked at 6:20 PM ET. This was an X2.1 class flare, some four times stronger than the earlier flare. Flares can affect Earth's ionosphere, through which high frequency radio waves travel, and cause radio blackouts. This strength flare can cause a "strong" radio blackout, categorized as R3, which has the potential to cause about an hour-long blackout.

This flare, too, had a coronal mass ejection (CME) – an eruption of a giant cloud of solar material -- associated with it. Early models suggest that both CMEs will not travel directly toward Earth, but perhaps just graze our atmosphere in the North, potentially causing auroras in the northern latitudes.

Further updates on the event will be provided as they become available.

NASA's GRAIL spacecraft are set to launch to the moon aboard a United Launch Alliance Delta II rocket on Sept. 8, 2011, from Cape Canaveral Air Force Station, Fla. There are two instantaneous (one-second) launch windows at 5:37:06 a.m. and 6:16:12 a.m. PDT (8:37:06 a.m. and 9:16:12 a.m. EDT). The launch period extends through Oct. 19. The launch times occur approximately four minutes earlier each day.

GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon.

The lunar orbiters are nestled inside the top of a United Launch Alliance Delta II 7920H-10C rocket, the most powerful Delta rocket in NASA's inventory.

On launch day, Sept. 8, NASA TV commentary coverage of the countdown will begin at 3 a.m. PDT (6 a.m. EDT). The coverage will be webcast at http://www.nasa.gov/ntv .

Live countdown coverage on NASA's launch blog also begins at 3 a.m. PDT (6 a.m. EDT) at http://www.nasa.gov/mission_pages/grail/launch/grail_blog.html . Coverage features real-time updates of countdown milestones, as well as streaming video clips highlighting launch preparations and liftoff. To access these features, and for more information on GRAIL, visit http://www.nasa.gov/grail and http://grail.nasa.gov .

The launch will also be online, with a live chat available, on Ustream TV, at http://www.ustream.tv/nasajpl2 . To follow the GRAIL launch on Twitter, visit http://twitter.com/NASAJPL and http://twitter.com/NASA .

Here is a timeline of expected launch milestones:

Launch

At liftoff, the rocket's first-stage engine and six of its nine strap-on solid rocket motors will ignite, and the rocket will be airborne, carrying GRAIL up and over the Atlantic Ocean.

First six solid rocket motors are jettisoned

GRAIL's Delta II is carrying nine strap-on graphite-epoxy motors. The first six will be ignited at the time of liftoff. The remaining three will be ignited shortly after the first six strap-on motors burn out.

Fairing separates

After the Delta's first stage completes its tour of duty, its second stage, which will provide 9,645 pounds of kick for GRAIL, will begin the first of two scheduled burns.

Shortly after ignition of the rocket's second stage, the Delta's 30-foot-long (8.88-meter-long) nose cone, or fairing, will separate and be jettisoned as planned, providing the GRAIL twins with their first taste of exo-atmospheric existence.

Parking at 17,500 miles per hour

The Delta's second stage will temporarily stop firing, as planned, and the rocket and GRAIL will begin a planned coast phase, also known as a "parking orbit" at about 90 miles (nearly 167 kilometers up).

GRAIL heading from Earth to the moon

The Delta's second stage will begin a second burn. This approximately four-and-a-half-minute-long burn will place GRAIL on its desired trajectory to the moon.

Spacecraft begin to separate from second stage

The GRAIL-A spacecraft begins its separation process from the Delta's second stage. The GRAIL-B spacecraft separates about 8 minutes later. At this point, the moon is three-and-a-half months away.

NASA will host a media teleconference on Thursday, Sept. 1, at 12:30 p.m. PDT (3:30 p.m. EDT) to discuss progress of NASA's Mars Exploration Rover Opportunity. Opportunity reached the Martian Endeavour crater earlier this month after years of driving.

The teleconference participants are:

-- Dave Lavery, program executive, Mars Exploration Rovers, NASA Headquarters, Washington

-- Steve Squyres, principal investigator, Mars Exploration Rovers, Cornell University, Ithaca, N.Y.

-- Ray Arvidson, deputy principal investigator, Mars Exploration Rovers, Washington University in St. Louis.

-- John Callas, project manager, Mars Exploration Rovers, Jet Propulsion Laboratory, Pasadena, Calif.

Opportunity and its twin, Spirit, completed their three-month prime missions on Mars in April 2004. They continued to work for years in bonus mission extensions. Spirit finished communicating in 2010, after six years of operation.

Opportunity, still very active, reached the rim of Endeavour crater on Aug. 9. The arrival gives the rover access to geology different from any it explored during its first 90 months on Mars.

At 9:35 PM ET on September 5, 2011, the sun emitted an Earth-directed M5.3 class flare as measured by the GOES satellite. The flare erupted from a region of the sun that appears close to dead center from Earth's perspective, an active region designated number 1283. The flare caused a slight increase of solar energetic protons some 26,000 miles above Earth's surface.

A coronal mass ejection (CME) -- another solar phenomenon that can send solar particles into space -- was associated with this flare. The CME is a relatively slow one, traveling at under 200 miles per second.

Further updates on the event will be provided as they become available.

NASA has invited 150 followers of the agency's Twitter accounts to a two-day launch Tweetup Sept. 7-8. The Tweetup is expected to culminate in the launch of the twin moon-bound GRAIL spacecraft aboard a Delta II rocket from Cape Canaveral Air Force Station in Florida.

The launch is targeted for 5:37 a.m. PDT (8:37 a.m. EDT) on Sept. 8. The two GRAIL spacecraft will fly in tandem orbits around the moon for several months to measure its gravity field in unprecedented detail from crust to core. The mission also will answer longstanding questions about the moon and provide scientists with a better understanding of how Earth and other rocky planets in the solar system formed.

Tweetup participants were selected from more than 800 people who registered online. They will share their Tweetup experiences with their followers through the social networking site Twitter.

Participants represent the United States, Australia, Brazil, Canada, India, Indonesia, Spain and the United Kingdom. Attendees from the U.S. come from 32 states: Alabama, Arizona, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Illinois, Indiana, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, New Hampshire, New York, North Carolina, Ohio, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Virginia, Washington and Wisconsin.

Beginning at noon PDT (3 p.m. EDT) on Wednesday, Sept. 7, NASA will broadcast a portion of the Tweetup when attendees talk with NASA Administrator Charles Bolden; Jim Adams, deputy director of planetary science at NASA Headquarters in Washington; Maria Zuber, GRAIL principal investigator at the Massachusetts Institute of Technology in Cambridge; Sami Asmar, GRAIL deputy project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif.; and Neil deGrasse Tyson, astrophysicist and Frederick P. Rose Director at the American Museum of Natural History's Hayden Planetarium in New York. To watch the broadcast, visit: http://www.ustream.tv/channel/nasa-tweetup . The event will also be streamed live, with a moderated chat, at http://www.ustream.tv/nasajpl2 .

Participants also will tour NASA's Kennedy Space Center and Cape Canaveral, including a close-up visit to the launch pad.

Reporters interested in interviewing Tweetup attendees should contact Stephanie Schierholz at 202-358-1100 or stephanie.schierholz@nasa.gov. Reporters interested in covering the afternoon program Sept. 7 at the Kennedy Space Center Visitor Complex must secure access through Andrea Farmer by 2 p.m. PDT (5 p.m. EDT) Sept. 6 at 321-449-4318 or afarmer@dncinc.com.

Previously, NASA invited groups to attend the launch of the Juno spacecraft on its way to Jupiter and five space shuttle launches: Atlantis' STS-129, STS-132 and STS-135 missions, Discovery's STS-133 mission and Endeavour's STS-134 mission.

To follow participants on Twitter as they experience the prelaunch events and GRAIL's liftoff, follow the #NASATweetup hashtag and the list of attendees at: http://twitter.com/nasatweetup/grail-launch.

Astronomers using NASA's Chandra X-ray Observatory discovered the first pair of supermassive black holes in a spiral galaxy similar to the Milky Way. Approximately 160 million light years from Earth, the pair is the nearest known such phenomenon.

The black holes are located near the center of the spiral galaxy NGC 3393. Separated by only 490 light years, the black holes are likely the remnant of a merger of two galaxies of unequal mass a billion or more years ago.

"If this galaxy wasn't so close, we'd have no chance of separating the two black holes the way we have," said Pepi Fabbiano of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., who led the study that appears in this week's online issue of the journal Nature. "Since this galaxy was right under our noses by cosmic standards, it makes us wonder how many of these black hole pairs we've been missing."

Previous observations in X-rays and at other wavelengths indicated that a single supermassive black hole existed in the center of NGC 3393. However, a long look by Chandra allowed the researchers to detect and separate the dual black holes. Both black holes are actively growing and emitting X-rays as gas falls towards them and becomes hotter.

When two equal-sized spiral galaxies merge, astronomers think it should result in the formation of a black hole pair and a galaxy with a disrupted appearance and intense star formation. A well-known example is the pair of supermassive black holes in NGC 6240, which is located about 330 million light years from Earth.

However, NGC 3393 is a well-organized spiral galaxy, and its central bulge is dominated by old stars. These are unusual properties for a galaxy containing a pair of black holes. Instead, NGC 3393 may be the first known instance where the merger of a large galaxy and a much smaller one, dubbed a "minor merger" by scientists, has resulted in the formation of a pair of supermassive black holes. In fact, some theories say that minor mergers should be the most common way for black hole pairs to form, but good candidates have been difficult to find because the merged galaxy is expected to look so typical.

"The two galaxies have merged without a trace of the earlier collision, apart from the two black holes," said co-author Junfeng Wang, also from CfA. "If there was a mismatch in size between the two galaxies it wouldn't be a surprise for the bigger one to survive unscathed."

If this was a minor merger, the black hole in the smaller galaxy should have had a smaller mass than the other black hole before their host galaxies started to collide. Good estimates of the masses of both black holes are not yet available to test this idea, although the observations do show that both black holes are more massive than about a million suns. Assuming a minor merger occurred, the black holes should eventually merge after about a billion years.

Both of the supermassive black holes are heavily obscured by dust and gas, which makes them difficult to observe in optical light. Because X-rays are more energetic, they can penetrate this obscuring material. Chandra's X-ray spectra show clear signatures of a pair of supermassive black holes.

The NGC 3393 discovery has some similarities to a possible pair of supermassive black holes found recently by Julia Comerford of the University of Texas at Austin, also using Chandra data. Two X-ray sources, which may be due to supermassive black holes in a galaxy about two billion light years from Earth, are separated by about 6,500 light years. As in NGC 3393, the host galaxy shows no signs of disturbance or extreme amounts of star formation. However, no structure of any sort, including spiral features, is seen in the galaxy. Also, one of the sources could be explained by a jet, implying only one supermassive black hole is located in the galaxy.

"Collisions and mergers are one of the most important ways for galaxies and black holes to grow," said co-author Guido Risaliti of CfA and the National Institute for Astrophysics in Florence, Italy. "Finding a black hole pair in a spiral galaxy is an important clue in our quest to learn how this happens."

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.