A drone flight over ESO’s experimental sites in Chile
This article is a republication from the CERN Bulletin.
Paola Catapano presents additional aspects on her visit to ESO with Mike Struik.
Paola Catapano, a member of CERN’s Communication Group, and Mike Struik, a member of the CERN TE Department, were invited to visit ESO’s experimental sites – the ALMA observatory and the Very Large Telescope in Paranal, Chile. Enjoy some of the beautiful images they sent to the Bulletin.
The 66 radio astronomy antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) observatory at 5,000 m altitude on the Chajnantor highland in Chile. The ALMA array specialises in the cold, invisible Universe, catching radiation from millimetre and submillimetre radiowaves night and day. ALMA is an international partnership between the European Southern Observatory (ESO), the US National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan, together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. (Image courtesy Paola Catapano and Mike Struik.)
Sunset at ESO’s Very Large Telescope (VLT). Situated at an altitude of 2,600 m on the Paranal mountain, VLT is the most powerful optical telescope in the world. It consists of four 8.2 m diameter Unit Telescopes (UTs) and four 1.8 m aperture Auxiliary movable Telescopes (ATs). The UTs work either individually or in a combined mode using interferometry, while the ATs are entirely dedicated to interferometry. The Interferometer of the VLT (VLTI) is the most advanced optical interferometry facility in the world. (Image courtesy Paola Catapano and Mike Struik)
The Armazones peak, about 20 km from Paranal, where construction work has started on the European Extremely Large Telescope (E-ELT). Its 39-metre diameter mirror will be the largest astronomical mirror ever built. Thanks to these huge dimensions, the telescope will be able, among other things, to search for life on other planets.( Image courtesy Paola Catapano and Mike Struik.)
Atacama, a 1,000-kilometre strip of land on the Pacific coast, west of the Andes, is the driest non-polar desert on the planet. Its exceptional aridity and the high contents of salt, clay and boron, make of this place the closest to the surface of the Moon or Mars you can find on Earth. This is where the lunar and Martian rovers were tested before being launched to space. But this is also where European astronomy has decided to place its giant and most powerful astronomical instruments. Main advantages: atmospheric conditions comparable to those encountered in space, granting images without distortions, and a perfectly dark sky, with no light pollution (nobody can live in such an arid desert!).
What is ideal for telescopes is not necessarily human friendly! Especially if you’re a small (three people) low budget crew on a road trip with the ambitious mission of producing a one hour TV documentary, aerial photography and film, and science popularization stories illustrated by photos.
First requirement: two 4×4 cars (one is not enough to cross deserts safely) equipped with “anti-vuelco” (roll) bars, for better protection in case of accidents (whose number is not small, judging from the “animitas”, the colourful funerary monuments on both sides of the long straight roads through the desert); sun glasses, solar cream, windproof and warm technical clothes, that we had to wear in layers on your 20 hour long flight to Chile, with all the space in your shipped luggage taken by photographic equipment and two drones; loads of water and disposable oxygen bottles (slash coca leaves to chew) are essential life savers. Photo, video and sound equipment have to be adapted to the harsh conditions too. We chose rugged dust-proof stuff, with plenty of batteries, hard disks for daily backups and polarizing filters for the harsh light. For the aerial videos, neutral density filters to lengthen shutter speed on the fixed aperture camera (gopro hero4, f2.8) were crucial to obtain smooth images. With adequate pre-trip preparation and careful choices, this was not the most difficult part of the expedition. One major difficulty was choosing the type of photography among plenty of not to be missed options, day and night, from aerial to still, time-lapses, panorama and video. Frustrating not to be able to do all, everywhere and at the same time!
The most challenging part of the expedition was covering ALMA. The 66 parabolic antennas of the most complex astronomical observatory in the world were conceived to catch, for the first time ever, the very faint radio emissions from the milimetric and sub-millimetric waves of the e-m spectrum, a cold and so far unexplored region of the cosmos. The Andean highland is probably the only location on the planet offering a huge flat site (16 km2), with ideal atmospheric conditions: almost no humidity and year-round cold temperatures. The price to pay at the literally breath-taking altitude of 5100 m above sea level: a temperature of -15 C, made harsher by a 30km wind and … half the oxygen you need! If your goal is to fly a drone there, freezing hands and low oxygen were not the biggest challenge though. We had to provide a flight plan that avoided to fly over the antennas; moreover, using the transmitter for the video downlink was forbidden by ESO, not to interfere with the antenna’s radio signals.
“I had to pre-heat the batteries on my body and to fly blind, without seeing what the drone was seeing and with the constant stress of an imminent crash” – says Mike Struik, who designed and built the foldable quadcopter from components bought online. Thanks to its bigger than usual propellers, faster running motors and insulated batteries, the drone flew flawlessly for about 10 minutes per LiPO battery and the spare quadcopter we took along as hand luggage rested in its flight case for the entire trip.
