New Lasers and Aircraft

Global Ecosystem Dynamics Investigation (GEDI) is on right in the SpaceX Dragon unpressurized trunk before delivery to the International Space Station. Image courtesy of NASA.

There have been some interesting first steps within the Earth Observation industry this week. Firstly, NASA provided the first data from it’s Global Ecosystem Dynamics Investigation (GEDI) mission – pronounced Jedi!! The mission was sent up to the International Space Station in a Dragon capsule on board the SpaceX Falcon 9 vehicle on the 5th December last year. The following week, on the 13th, it was installed on the outside of the International Space Station on the Japanese Experiment Module-Exposed Facility.

GEDI’s instrument is a lidar laser system made up of three lasers, two of which are full power and the final one is split into two beams, producing a total of four beams. These use an active remote sensing method by firing pulses of light at the planet and detecting the returning reflected light signal, producing eight tracks across a 4.2 km wide swath of the Earth at a footprint resolution of 25 m. It aims to create detailed 3D maps of the Earth’s forest and topography using lasers, and turned on the lasers for the first time in January which has provided the initial datasets.

The lasers fire two hundred and fifty times a second, and the resulting lidar waveform can give information on the varying heights of vegetation and structures producing a high-resolution 3D image which can give information on surface topography, canopy height, canopy cover, and other vertical structure.

NASA Earth Observatory images by Joshua Stevens, using GEDI data courtesy of Michelle Hofton/University of Maryland.

This initial dataset shows the profile of a South Carolina woodland from this winter, can be seen on the right, where it shows heights alongside how dense the canopy is. Eventually, GEDI will make more than 10 billion measurements, during its scheduled two-year mission life, which had an estimated cost at launch of $94 million.

GEDI will provide information to support a range of scientific research on biodiversity, biomass change and ecosystems, and specifically:

  • Forest management and carbon cycling – through better understanding of forest heights and density; together with habitat, how much carbon is in forests, and how this changes through events such as fires and hurricanes.
  • Water resources – through understanding how the canopy influences elements such as snowmelt and evapotranspiration.
  • Weather predictions – through how the canopy aerodynamics can influence weather.
  • Topography and surface deformation – to help improve digital elevation models.

All GEDI data will be made freely available to download once they have been released, although there will be a time lag between the data being acquired and released.

Also last week, on Saturday, 13th April, the largest plane ever built with its 385-foot wingspan had its first ever flight in the Mojave Desert in the USA. Built by Stratolaunch -a company founded by Paul Allen, who also co-founded Microsoft, and who sadly passed away last year – it hopes to offer a satellite launching capability within three years. The intention is that the plane will carry a rocket loaded with a satellite up to an altitude of 35 000 feet, where the rocket will be launched to take the satellite to its intended orbit. There is still a long way to go before this becomes a realistic launch vehicle option, but it is one example of innovation coming into the industry.  Of course, they are not alone as Richard Branson’s Virgin Orbit company also has plans to offer a launch facility for small satellites via an adapted Boeing 747-400. They hope to conduct their first launch later this year.

This week provides good examples of how the industry is constantly changing with new ideas, innovations and technologies.

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