Free Astronomy Magazine January-February 2018

36 JANUARY-FEBRUARY 2018 SPACE CHRONICLES ESA: crossing drones with satellite by ESA E SA is considering extending its activities to a new region of the sky via a novel type of aerial ve- hicle, a ‘missing link’ between drones and satellites. High Altitude Pseudo-Satellites, or HAPS, are plat- forms that float or fly at high alti- tude like conventional aircraft but operate more like satellites – except that rather than working from space they can remain in position in- side the atmosphere for weeks or even months, offering continuous coverage of the territory below. The best working altitude is about 20 km, above the clouds and jet streams, and 10 km above commer- cial airliners, where wind speeds are low enough for them to hold posi- tion for long periods. From such a height they can survey the ground to the horizon 500 km away, variously enabling precise monitoring and surveillance, high- bandwidth communications or back up to existing satellite navigation services. Several ESA directorates have teamed up to investigate their po- tential, explains future-systems spe- cialist Antonio Ciccolella: “For Earth observation, they could provide pro- longed high-resolution coverage for priority regions, while for naviga- tion and telecoms they could shrink blind spots in coverage and com- H igh Altitude Pseudo-Satellites, or HAPS, are platforms that float or fly at high altitude like conventional aircraft but operate more like satellites – ex- cept that rather than working from space they can remain in position inside the atmosphere for weeks or even months, variously enabling precise monitor- ing and surveillance, high-bandwidth communications or back up to existing satellite navigation services. [ESA Earth Observation Graphics Bureau] bine wide bandwidth with negligi- ble signal delay. ESA is looking into how these various domains can be best brought together.” Earth ob- servation specialist Thorsten Fehr explains: “We’ve been looking into the concept for the last 20 years but now finally it’s becoming reality. That’s come about through the ma- turing of key technologies: minia- turised avionics, high-performance solar cells, lightweight batteries and harness, miniaturisation of Earth observation sensors and high-band- width communication links that can deliver competitively priced ser- vices.” Navigation engineer Roberto Prieto Cerdeira adds: “There’s obvious po- tential for emergency response.