Ball
Ball

Sharp-Eyed Spacecraft Showcases New Tech

WorldView-3


By Leonard David & Roz Brown

What do you know about remote sensing?  Maybe you’ve heard people say while looking at their smart phone, “That’s a Google image.”  O.K., that’s partly right.  The Google search engine has provided the user image. Google, however, doesn’t have satellites in space to capture images. Instead, they purchase remote-sensing satellite imagery from commercial providers such as DigitalGlobe.  DigitalGlobe in turn, contracts with Ball Aerospace to build the satellites along with specialized instruments that fly aboard the satellites.

When WorldView-3 hurled spaceward from Vandenberg Air Force Base in 2014, it became the fourth Ball-built satellite in the DigitalGlobe constellation. As with previous DigitalGlobe satellites, Ball was also responsible for development, integration and testing of the spacecraft.  It continues to deliver on the pre-launch promise of opening a new era in commercial Earth remote sensing as the newest ultra-powerful eye in the sky, producing the most sophisticated images yet available for commercial applications.
 

WHAT IS REMOTE SENSING?


The term “remote sensing” was introduced in 1960, after aerial photography was surpassed by new methods and technologies for sensing the Earth’s surface.  Those advances were coming from satellites, which soon became the primary platform used to carry remote sensing instruments.  At the same time, computers were advancing by leaps and bounds to allow a switch from analog to digital to view the imagery. And with sensor technology thrown into the mix, the Earth’s surface revealed through the electro-magnetic spectrum revealed much greater detail than an aerial photograph. 
 

REVISIT TIME


The WorldView satellites operate just a few hundred kilometers above the Earth. This means they only see a small part of the Earth with their camera as they orbit overhead. But the red-hot satellite resolution means the detail of what they see is better than ever!

 “WorldView-3 was launched and commissioned in August 2014, and the satellite is now providing DigitalGlobe’s customers with the world’s highest resolution commercial satellite imagery, captured at 30 centimeter Ground Sample Distance,” says Turner Brinton, a DigitalGlobe spokesperson.

With an estimated service life of 10 to 12 years, Brinton adds that WorldView-3 has an average revisit time of less than one day and is capable of collecting up to 680,000 square kilometers per day.
 

FAST DATA DELIVERY


WorldView-3 is a lookalike, in many ways, to WorldView-2 launched on October 8, 2009 in terms of its performance characteristics. It tips the scales at 6,200 lbs. (2,812 kilograms) and measures 19 feet tall and 23 feet wide (5.8 by 7 meters) with its solar panels deployed. But WorldView-3 also boasts significant improvements including cost savings, risk reduction, and faster delivery of data for customers.

Adding to WorldView-3’s many attributes is a Ball-provided atmospheric instrument called CAVIS - short for Cloud, Aerosol, water Vapor, Ice, Snow. It’s the duty of CAVIS to observe the atmosphere and provide correction data to improve WorldView-3’s imagery when it pictures the Earth, explains Jeff Dierks, Senior Program Manager, WorldView-3 at Ball Aerospace. 

CAVIS boosts the color band of images, Dierks points out, making it possible to target ground scenes and correct images taken through aerosols and water vapor in the imaging column, and also helps quickly identify clouds, ice and snow in an image.  
 

DESIGN LIFE


WorldView-3 was built on the Ball Configurable Platform BCP 5000 spacecraft - a flexible, stable and highly accurate Earth remote sensing platform with a design life of more than seven years. 

By using advanced Control Moment Gyroscopes (CMGs) on the spacecraft, Dierks notes that WorldView-3 can be reoriented over a desired collection area in 4-5 seconds, compared to 30-45 seconds needed for traditional reaction wheels used on satellites.
 

SEEING A BETTER WORLD


Every hour of the day, remote sensing satellites are gathering scientific information about the planet and monitoring its changes. The monitoring helps decision makers better understand our changing planet in order to save lives, resources and time. Today, many satellites, with various remote sensing instruments, monitor the Earth’s surface, including the Landsat constellation overseen by the National Oceanic and Atmospheric Administration and the U.S. Geological Survey. The most recent in that constellation is Landsat 8, hosting the Ball Aerospace provided Operational Land Imager. 
 

BEFORE WV3: QUICKBIRD


The first remote-sensing satellite in the DigitalGlobe constellation built by Ball Aerospace was called QuickBird.
  • QuickBird spent 13 years on orbit, exceeding its five-year design life by more than eight years. 
  • QuickBird made 70,000 trips around the Earth during its lifetime.
  • QuickBird was de-orbited after exhausting its fuel supplies in January 2015.  
  • QuickBird circled the globe 450 km (about 280 miles) above Earth while Ball’s high-resolution camera onboard gathered images of the Earth's surface during daylight hours. 
  • QuickBird’s world-class images have contributed significantly to mapping, agricultural and urban planning, weather research and military surveillance.