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STS-120: The programs

In advance of shuttle Discovery's STS-120 mission to the station, managers from both programs discuss the flight.


STS-120: The mission

Discovery's trip to the station will install the Harmony module and move the P6 solar wing truss. The flight directors present a detailed overview of STS-120.

 Part 1 | Part 2

STS-120: Spacewalks

Five spacewalks are planned during Discovery's STS-120 assembly mission to the station. Lead spacewalk officer Dina Contella previews the EVAs.

 Full briefing
 EVA 1 summary
 EVA 2 summary
 EVA 3 summary
 EVA 4 summary
 EVA 5 summary

The Discovery crew

The Discovery astronauts, led by commander Pam Melroy, meet the press in the traditional pre-flight news conference.


STS-69: The Dog Crew

Astronauts flying aboard shuttle Endeavour in September 1995 called themselves the Dog Crew, a lighthearted twist to their complicated mission to launch and then retrieve a pair of satellites.


Riding on Endeavour

Now you can take a virtual trip aboard shuttle Endeavour's recent launch thanks to video cameras mounted inside the ship's cockpit as well as outside on the twin solid rocket boosters and external tank.

 Full Coverage

"The Time of Apollo"

This stirring 1970s documentary narrated by Burgess Meredith pays tribute to the grand accomplishments of Apollo as men left Earth to explore the Moon and fulfill President Kennedy's challenge to the nation.


"Apollo 17: On The Shoulders of Giants"

Apollo's final lunar voyage is relived in this movie. The film depicts the highlights of Apollo 17's journey to Taurus-Littrow and looks to the future Skylab, Apollo-Soyuz and shuttle programs.


Traveling on Freedom 7

Fly with Alan Shepard during his historic journey into space with this documentary that takes the viewer along as an invisible companion to America's first astronaut.


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Delta 2 rocket launches to new success record

Posted: September 18, 2007

A sophisticated new Earth-imaging satellite with sharp eyes, nimble moves and a broad memory was launched Tuesday, riding the ever-dependable Delta 2 rocket into orbit during a flawless ascent that set a new reliability mark for modern space boosters.

The uneventful countdown was punctuated by an on-time liftoff at 11:35 a.m. local time (2:35 p.m. EDT; 1835 GMT) from Vandenberg Air Force Base, California. The 12-story rocket raced off the launch pad, roaring up through a deck of low clouds as it began to arc southward with the WorldView 1 satellite tucked neatly in its nose cone.

Credit: Carleton Bailie for Boeing and ULA

It took 73 minutes for the two-stage launcher to accomplish the job of hoisting the two-and-a-half-ton satellite to the proper orbit, then safely deploying WorldView for its mission to survey the globe with advanced imaging capabilities.

Cheers and applause burst out in the control rooms when the successful launch was confirmed, and the joy seemed a little sweeter this time because a milestone for the rocket business had just been achieved.

It was the 75th consecutive successful ascent for the Delta 2 rocket. No other single rocket design in the current era has strung together such a long and spotless track record.

Delta 2 has been perfect since May 1997, amassing its consecutive string by launching spacecraft for military, NASA and commercial users, including the Global Positioning System satellites, the twin Mars rovers Spirit and Opportunity, the Spitzer Space Telescope and the Mercury-bound MESSENGER orbiter. In the rocket's 130 flights overall since debuting in 1989, 128 of those launches have been successful.

"I love the Delta 2. We've been able to meet schedule, we've been able to put some exciting, exciting payloads out into orbit. I think one of the things that's revolutionized the world is the GPS system. We were the ones that put all of those satellites up into orbit," said Kris Walsh, United Launch Alliance's director of NASA and commercial programs for the Delta rocket.

"So I think it's been a tremendous boon for the United States government and commercial (customers). It's a great little rocket. I'll continue to fly it as long as I can."

The Delta 2's future

There are 25 Delta 2 rockets remaining to fly over the next few years. "It's a pretty firm number, if we don't end up starting production again," Walsh said.

The future launches include 11 flights for NASA counting next week's Dawn asteroid probe, the five remaining GPS 2R satellites for the Air Force, three commercial missions and six rockets not yet sold, Walsh said.

Credit: Tim Madden

Keeping the Delta 2 around for the long-term depends on finding a government partner. The Pentagon and NASA have shared the costs over the past years. But the military will soon end its use of the Delta 2 in favor of the Evolved Expendable Launch Vehicles.

The Air Force has backed the Delta 2 since the rocket's earliest days for launching the GPS constellation. But after the five remaining satellites in the current series are launched soon, the Air Force will be turning its attention to next-generation spacecraft that will fly on the larger Atlas 5 and Delta 4 boosters.

That will leave NASA as the main government user of Delta 2. Thus far, the space agency has been reluctant to fund future production of the rocket and the associated infrastructure maintenance entirely on its own.

"We'll continue (Delta 2) as long as it's a viable rocket and we have a government anchor customer," Walsh said.

The new sharp-eyed orbiter

Benefiting from the rocket's consecutive success No. 75 was the WorldView 1 spacecraft. Circling 300 miles above the planet in polar orbit, ringing around Earth once every 95 minutes, the commercial Earth-imaging satellite will offer a clarity not possible by any civilian satellite in orbit today.

Despite the lofty perch in space, the satellite's remarkable vision can see objects on the ground as small as 20 inches across. And its advanced picture-taking sensor package can produce such images with half-meter resolution covering 290,000 square miles of the planet's surface per day.

The anticipated quality has the U.S. government signed up as a customer to receive WorldView's images of specific global hot spots and areas of interest for intelligence-gathering. And the growing potential of commercial applications for such imagery ranges from urban planners, real estate developers, environmental monitors and users of the wildly popular Google Earth.

DigitalGlobe, based in Longmont, Colorado, has operated its QuickBird satellite for nearly six years. But the imminent addition of WorldView 1 promises to generate five times the image-collecting capacity.

WorldView 1 is pictured here atop the Delta rocket as the two-piece nose cone is installed. Credit: DigitalGlobe
"Being able to satisfy many more customer orders and larger area collections is really the big differentiator from QuickBird and our new satellite WorldView," said Chuck Herring, DigitalGlobe's director of corporate communications.

The two spacecraft working in tandem will allow imaging a specific spot on Earth each day, cutting the current three-to-five-day "revisit" rate of the solo QuickBird.

WorldView 1 also boasts a much greater agility than its predecessor. Orientation-controlling gyroscopes, called control moment gyros, are flying on the Ball Aerospace-built craft, marking the first time such devices have been used by a commercial imaging satellite, Herring said.

The gyros will enable the spacecraft to point itself about 10 times faster than QuickBird. That should increase the satellite's picture-shooting time because imaging cannot begin until after the craft completes its turns and takes aim.

"The biggest thing is our ability to collect a lot more imagery," Herring said.

DigitalGlobe officials are anticipating being able to show off initial imagery from WorldView 1 in about a month, just in time to coincide with the sixth anniversary of QuickBird's launch on a Delta 2 rocket from Vandenberg.

If all goes well, WorldView 1 should be fully operational by year's end.

The growing market for Earth-imaging

Until WorldView enters service, QuickBird remains the highest resolution commercial satellite of its type. But WorldView 1 will be slightly better, offering 0.5-meter meter clarity versus 0.6-meter.

"For the casual wouldn't see a huge difference in the imagery. (To) an imagery analyst, there is a difference in the resolution," Herring said.

A key constituent of WorldView's products will be the National Geospatial-Intelligence Agency. The government awarded a contract to DigitalGlobe four years ago in excess of $500 million to help launch the next-generation satellite.

"They have areas on the ground they like us to image. We image them and send over the imagery," Herring said. "It is not as though all of the imagery that we take goes to them. They have the ability to request areas that we will image...They're also able to purchase from the library as well."

An artist's concept of WorldView 1. Credit: Ball Aerospace
The demand for data from the relatively young commercial Earth-imaging business is soaring, officials say, as customers learn new ways to use the information.

"What we're really seeing is because of the availability...the applications are growing exponentially," Herring said.

State and local governments use the imagery to keep tabs on urban growth, real estate developers can assess building plans, insurance companies map out areas threatened by a high wildfire risk and scientists can study environmental changes.

"At the beginning of our operations, people would call and they wanted to track animals - herd of elephants - because of the resolution they could see elephants. What we are finding is it's less about understanding the individual animals and more about understanding the environment in which they live and mapping it out, doing change detection," Herring said.

"It's mapping the ecosystem, then keeping an up-to-date view of that ecosystem, understanding the human and environmental impacts that are occurring in those ecosystems, if they put in a new walking path, there's deforesting going on or drought, how does it impact the ecosystem."

DigitalGlobe's QuickBird is expected to operate for another two years, and the new WorldView 1 has a life expectancy of about seven-and-a-half-years. Builder of those two satellites, Ball Aerospace, is constructing the WorldView 2 craft for launch perhaps by the end of 2008. It could fly aboard one of the remaining yet-unsold Delta 2 rockets.

Continuing to grow the commercial imagery market will require more satellites, enabling the companies to keep their picture supply as fresh as possible and expand the regions covered with high-resolution photos.

"The industry needs to get more satellites up to address people's wish to not only update on a regular basis but paint the globe," Herring said.

"From a global mapping standpoint, we haven't even really started to address less populated areas, let alone rural areas."