WorldView-4 launches Friday to bring us trillions of pixels

Charlie Loyd
Tue, 13 Sep 2016 14:00:00 -0400

WorldView-4, a cutting edge imagery satellite, launches on Friday. Once in orbit and calibrated, it will collect up to 7 terapixels of ultra-high-res image data every day. WorldView-4 is the newest satellite from our partners at DigitalGlobe, and it’s going to be a real workhorse. We’re hosting a launch viewing for DigitalGlobe in San Francisco, and we’d like to see you there!

A DigitalGlobe rendering of WorldView-4 as it will look in orbit.

Here’s why we’re looking forward to watching the satellite head to space:

WorldView-4’s big feature is its small pixels – 30 cm (1 ft) square, the sharpest of any commercial satellite. It’s tied with WorldView-3, its slightly older sibling, which has proven the demand for that resolution. (30 cm is sharper than civilians were allowed to see only a couple years ago.) WorldView-4 will more than double the amount of the highest-resolution satellite data on the market. That’s great for everyone who needs the best possible imagery – like us, as we continually update our satellite map.

There are fewer high-resolution satellites in orbit than you might think. If you want an image of a particular place on a particular day, often you can’t get it at the resolution you want. To collect sharper images from more angles, WorldView-4 has a very large telescope and the ability to pivot its field of view hundreds of miles in any direction.

WorldView-4 is particularly good at pointing, which means it will maximize imaging time over its tasked areas. After collecting an image strip, it will be able to look 200 km (125 mi) away to start on a second strip within about 10 seconds. And it will be accurate: it’s designed point anywhere in its field of view to within 0.01° – about 100 m when looking straight down – and it records image locations to within 5 m before matching against ground features. Pointing is a tough problem for imaging satellites. They’re already rotating once per orbit in order to point down (in the terrestrial frame of reference). The motion of panning across Earth’s surface has to be calculated on top of that. And without any external braces or air resistance to dampen vibrations, there can be no extra momentum, or images would come out blurry.

Lockheed Martin technicians fit WorldView-4, folded up for launch, into the Atlas V rocket’s faring. Many characteristics of the satellite are defined by what can fit in the faring. Image courtesy of Lockheed Martin.

WorldView-4 weighs 2.5 tons and is the size of a large SUV, with five fold-out solar arrays as big as large banquet tables. It’s a space telescope, an 800 Mbps X-band radio transmitter, a data center, and a tiny photovoltaic power station – all built to survive a violent earthquake’s worth of shaking during launch, then work for about a decade in space. The problem-solving behind WorldView-4 is why other engineers look up to satellite engineers.

All this means more fresh, sharp imagery for us and for you. If you’ll be near San Francisco on Friday, request an invitation to our launch viewing by emailing Hannah at hannah@mapbox.com. If you can’t make it, we’ll tweet a link to the live launch stream from @Mapbox.