The round-the-globe flight of a solar-powered airplane, watched by the world, was a dream made reality by two men: Bertrand Piccard and André Borschberg.
Bertrand Piccard was born in Lausanne, Switzerland, on March 1, 1958, into a family of explorers. His grandfather, Auguste Antoine Piccard, was a physicist, inventor and explorer. As a physics professor at the Federal Polytechnic School in Zurich, the elder Piccard was friend of both Albert Einstein and Marie Curie, who discovered Uranium 235; he was also passionate about the protection of nature. On May 27, 1931, Auguste and Paul Kipfer took off in their balloon from Augsburg, Germany, and reached a world record altitude of 15,781 m (51,775 ft.). During this flight, Piccard was able to gather substantial data on the upper atmosphere, as well as measure cosmic rays. On August 18, 1932, launched from Dübendorf, Switzerland, Piccard and Max Cosyns made a second record-breaking ascent to 16,201 m (53,153 ft.). Auguste ultimately made a total of twenty-seven balloon flights, setting a final record of 23,000 m (75,459 ft.). He then turned his attention to the bottom of the sea. By 1937, he had designed the bathyscaphe Trieste, a small steel gondola built to withstand great external pressure. In 1953, the year it was launched, Auguste and his son—and co-designer—Jacques set a new world record by taking it down to a depth of 3,150 meters (10,330 ft.) in the Tyrrhenian Sea, with the aim of exploring deep marine life.
In 1960 Jacques Piccard set a record that still stands nearly 50 years later: together with Lt. Don Walsh of the U.S. Navy, he went down to a depth of 10,916 meters in the Mariana Trench, located in the western North Pacific Ocean. Auguste and Jacques Piccard subsequently worked together on the mesoscaphe Auguste Piccard, designed by the father and built by the son. It turned out to be one of the main attractions at the 1964 national exhibition in Lausanne. It was the first and largest-ever submarine built for pleasure trips, and took some 33,000 passengers down to the bottom of Lake Geneva and back.
Bertrand Piccard grew up in this world of ballooning and undersea exploration. It is scarcely surprising that his eyes turned skywards. As a child, when his father was working in the United States, he met such legends as the flying pioneer Charles Lindbergh; Hermann Geiger, who developed the art of landing on glaciers; and rocket designer Werner von Braun, inventor of the Apollo rockets, who invited him and his family to witness the launch of several space flights from Cape Canaveral. From an early age he was also fascinated by the study of human behavior in extreme situations. He received a degree from the University of Lausanne in psychiatry, specializing in hypnosis. His love of flight led him to obtain licenses to fly balloons, gliders, and motorized gliders. In Europe, he was one of the pioneers of hang-gliding and microlight flying, becoming the European hang-glider aerobatics champion in 1985.
On March 1, 1999, Bertrand Piccard and Brian Jones set off in the balloon Breitling Orbiter 3, a bright red, carbon-composite, egg-shaped craft measuring 16 ft. (4.9 m) long and 7 ft. (2 m) in diameter, from Château d’Oex in Switzerland on the first successful nonstop balloon circumnavigation of the globe—the first circumnavigation requiring no fuel for forward motion. Piccard and Jones, in close cooperation with a team of meteorologists on the ground, caught rides in a series of jet streams that carried them 25,361 miles to land in the Egyptian desert after a 45,755 km (28,431 mi) flight lasting 19 days, 21 hours, and 47 minutes. Following this success, Bertrand Piccard was decorated with the Légion d’Honneur, the Olympic Order, the Fédération Aéronautique Internationale (FAI) gold medal, the Harmon Trophy, and the Charles Green Salver, and was honored by the National Geographic Society and the Explorers Club. An honorary professor and an honorary doctor in science and letters, he also received the Grand Prix of the Académie des Sciences Morales et Politiques.
Indeed, it was just after his balloon touched down that Piccard conceived of an idea to fly around the world again, but this time in a heavier-than-air machine and without using a drop of fuel. Back in Switzerland, encouraged by his wife Michèle, Bertrand’s plans were soon underway. Then he met André Borschberg and persuaded him to join his impossible quest. Like Piccard, André Borschberg had been fascinated by aviation from his childhood. He trained as a fighter pilot in the Swiss air force, flying first Venoms and then Hunters and Tigers for over 20 years and specializing in aerobatics. Training as a mechanical and thermodynamics engineer, he also graduated at the MIT Sloan School of Management, becoming a consultant to the McKinsey firm. He then launched on his own account with two start-ups, and co-founded a company specializing in microprocessors:
In 1999 I had decided to make a break in my professional activities. I wanted to open up to new ideas and new people. It was in 2003 at the École Polytechnique Fédérale de Lausanne (EPFL), the Switzerland’s MIT that I met Bertrand Piccard. I already knew about his family and his world balloon flight so when he told me about his plan to fly around the world in a solar-powered airplane, I felt that here was somebody with whom I could associate. He asked me to lead a feasibility study and put together the technical team, while Bertrand found the partners to help back the project.1
It would take some 15 years for Piccard to raise the $170 million needed from companies including Omega, Solvay, Schindler, Nestlé, and ABB. In November 2003, following a feasibility study, they announced their project, in cooperation with the École Polytechnique Fédérale de Lausanne (EPFL), for a solar airplane they had decided to call Solar Impulse. “We did consider Solar Spirit, but in the end we chose Impulse as in French this gives the idea of starting something, even if in English impulsive means doing something on the impulse, without thinking, which was far from our case.”2
The company Solar Impulse SA was officially founded on June 29, 2004, by Bertrand Piccard, André Borschberg, Brian Jones and sports marketing specialist Luiggino Torrigiani. A core technology team was then put together and the first scientific partnership agreements signed with the Ecole Polytechnique Fédérale de Lausanne, the European Space Agency and Dassault Aviation. As a mechanical engineer, co-founder André Borschberg would direct the construction of each aircraft and oversee the preparation of the flight missions. By 2009, he had assembled a multi-disciplinary team of fifty specialists from six countries, assisted by approximately one hundred outside advisers.
While this was underway, Piccard realized that he would have to obtain a license to fly an airplane. He would have to train for this over six years, accumulating hundreds of hours before he was even allowed to fly a prototype. “We even went to see Paul MacCready of AeroVironment, the doyen of solar flight, who told us of his challenge, some twenty years before, of building and flying a solar airplane, Solar Challenger, across the English Channel. With him we were able to share our philosophy of making the impossible possible.”3 Eight years before, AeroVironmment’s unmanned Pathfinder had been equipped with a 99-ft wingspan (slightly longer than a Boeing 737) covered with 8 kW maximum of solar panels and a power source of six 1.5 kW electric motors. On September 11, 1995, Pathfinder had set an unofficial altitude record for solar-powered aircraft of 50,000 feet (15,000 m) during a 12-hour flight from NASA Dryden (see Chapter Ten). So the initial thinking of the EPFL team was for a similar, very large wingspan incorporating extremely efficient aerodynamics.
In early 2004, more detailed studies led to the first prototype version with its engines placed forward beyond the leading edges, in order to balance the thrust of the aircraft against the aerodynamic forces. The cockpit in this version would be in a separate under-wing nacelle. Finally, a third version was born from the work of the engineers who decided to opt for a first prototype with a non-pressurized cabin. It took boldness and confidence in the projections to freeze the design and start construction. In November 2007, after four years of research, complex calculations and simulations, Piccard and Borschberg presented the final design with a wingspan of 63 meters (206 ft.) and weighing 1,600 kg (3,527 lb.), registration HB-SIA.
In May 2008, the flight simulator, developed in collaboration with Dassault and EPFL, enabled both pilots to “fly” HB-SIA for the first time for up to 25 hours, equipped and harnessed as they would be for real flights: helmet, safety harness, parachute, and oxygen mask, and with food and accessories for their natural needs. Five projection screens arranged 210° around the cockpit gave the pilots the impression of live flight.
For over a decade André Borschberg had been studying and practicing yoga, recently with a sangi in India: “When you practice yoga and its body postures, you learn to become an observer about yourself and to release yourself from stressful situations. This would be of immense help during the marathon flight sessions.”4
By September 2008, after assembly of the cockpit and the tail boom of Solar Impulse HB-SIA, construction of the wing could begin at Dübendorf. Three rectangular carbon-fiber and honeycomb sandwich beams, the longest over 20 meters (65 ft.) in length, made by Décision SA, were placed end-to-end to form the central wing spar, the backbone of the wing, with its total span of 63.4 m (208 ft.). The Solar Impulse project then went through two further important test phases. In December, the Deutsches Zentrum für Luft und Raumfahrt (DLR) in Göttingen, an institute that specializes in aero elasticity calculations, carried out a week of vibration tests. These were aimed at assessing the risks of flutter, identifying the aircraft’s specific frequencies, and verifying by physical experimentation the match between the engineers’ theoretical models and the technical characteristics of the actual aircraft. The fuselage, the wing spar, and the horizontal and vertical stabilizers were assembled for the first time.
With the assistance of Eric Raymond, experienced solar airplane builder and pilot, 11,628 photovoltaic cells were mounted on the upper wing surface and the horizontal stabilizer to generate electricity during the day to power the electric motors and to charge the batteries allowing flight at night, theoretically enabling the single-seat plane to stay in the air indefinitely. Raymond also worked out propeller spinners and wing ribs.
In mid–February 2009, a series of more robust tests put the wing spar through its paces. These were designed to directly test its resistance to high loads. Fully conclusive, these impressive load tests were conducted in an almost religious silence in order to be able to hear the slightest crack, and also to permit the intense concentration and the essential coordination of all involved. The electrical generating set and propulsion system also underwent detailed testing: the four engines each developing 10 hp (7.5 kW), the 3.5-meter diameter (11.5 ft.) twin-bladed propellers, the lithium-polymer batteries, the optimization and control circuits, the cabling, and power controls. The combined efforts of each team member, the courage to undertake a completely new project, and the trust of all the partners, contributed to the construction of the aircraft, which was completed in June 2009. After its presentation to the public and the media, the integration work was finalized in the fall of the same year.
HB-SIA Solar Impulse 1 carried out its first tests in November, and on December 3 succeeded with its first “ground hop” at Dübendorf airfield with professional Daimler-Chrysler test pilot Markus Scherdel at the controls in the 3.8-cubic-meter cockpit. On April 7, 2010, watched by several thousand spectators, the plane, again piloted by Scherdel, made an 87-minute test flight from Payerne, a military base of the Swiss Air Force, located approximately halfway between Lausanne and Bern. Scherdel spent the time familiarizing himself with the prototype’s flight behavior and performing the initial flight exercises before making the first landing on the Vaudois tarmac. This flight reached an altitude of 1,200 m (3,937 ft.). On May 28, 2010, the aircraft made its first flight powered entirely by solar energy, charging its batteries in flight. Two weeks later, on May 24, André Borschberg took the controls of Solar Impulse 1 for the first time: “Coming from the world of jet fighter planes, I had to get used to the fact that in this airplane, everything happens extremely slowly. When you alter the flight controls, you have to wait a couple of seconds. We call this pilot-induced oscillations due to over-correcting. It was a question of learning new techniques, even for Bertrand Piccard who came from another world of balloons and gliders.”5
After three “fast taxi” trials along the Payerne runway, the man who had been in charge of building the solar airplane was at last able to get airborne in it himself. Watching was Prince Albert II of Monaco, one of the project’s patrons. In July 2010, Solar Impulse 1 achieved the world’s first manned 26-hour solar-powered flight, again flown by Borschberg. It took off at 6:51 a.m. Central European Summer Time (UTC+2) on July 7 from Payerne Air Base, Switzerland. Having flown through the night, it returned for a landing the following morning at 9:00 a.m. local time. During the flight, the plane reached a maximum altitude of 8,700 m (28,500 ft.). At the time, the flight was the longest and highest ever flown by a manned solar-powered aircraft; these records were officially recognized by the Fédération Aéronautique Internationale (FAI) in October 2010.
The next target was to fly outside Switzerland, making “European Solar Flights” to Brussels and then Paris. It was only natural that in late May 2011, Solar Impulse 1, which had obtained the patronage of the European Commission even before it had been built, should select Brussels as its first international destination, where her pilots met the leaders of the European institutions and used it as a tool to help raise public—as well as official—awareness about environmental matters.
On May 13, 2011, at 9:30 p.m. local time, the plane landed at Brussels Airport, after completing a 13-hour flight from its home base in Switzerland. It was the first international flight by the Solar Impulse 1, which flew at an average altitude of 6,000 ft. (1,800 m) for a distance of 630 km (391 mi.), with an average speed of 50 km/h (31 mph). The aircraft’s slow cruising speed required operating at a mid-altitude, allowing much faster air traffic to be routed around it. Bertrand Piccard said in an interview after the landing: “Our goal is to create a revolution in the minds of people … to promote solar energies—not necessarily a revolution in aviation.”
Next stop was the Paris International Air Show at Le Bourget as a “Special Guest.” On June 14, 2011, after a 16-hour flight, Borschberg successfully landed the aircraft at Bourget Field, Paris. Visitors to the Air Show—over 200,000 people—were able to approach very close to Solar Impulse 1 in the static display and every morning, weather permitting, to marvel at in-flight demonstrations of its silent electric motors. On June 5, 2012, the Solar Impulse 1, originally conceived as a one-seater, now adapted to allow both Piccard and Borschberg to co-pilot, successfully completed its first intercontinental flight, a 19-hour trip from Madrid to Rabat, Morocco. During the first leg of the flight from Payerne Air Base to Madrid, the aircraft broke several further records for solar flight, including the longest solar-powered flight between pre-declared waypoints (1,099.3 km [683 mi.]) and along a course (1,116 km [693 mi.]). Cruise speed: 70 kph (43 mph). Endurance: approximately 36 hours. It also flew an entire diurnal solar cycle, including nearly nine hours of night flying, in a 26-hour flight.
Soon after, Piccard nearly lost his co-pilot, when Borschberg was involved in a helicopter crash but emerged without a scratch.
In 2013, Solar Impulse 1 was taken across the Atlantic, where in May, Piccard and Borschberg made a cross-U.S. flight. They took off from Moffett Field in Mountain View, California, and flew to Phoenix Goodyear Airport in Arizona. Successive legs of the flight lasted between 14 and 22 hours: Dallas–Fort Worth Airport, Lambert–St. Louis International Airport, Cincinnati Municipal Lunken Airport to change pilots and avoid strong winds, and Washington’s Dulles International Airport. The aircraft’s second leg of its trip on May 23 to Dallas–Fort Worth covered 1,541 kilometers (958 mi) and set several new world distance records in solar aviation. On July 6, 2013, following a lengthy layover in Washington, Solar Impulse 1 completed its cross-country journey, landing at New York City’s JFK International Airport at 11:09 p.m. EDT. The landing occurred three hours earlier than originally intended, because a planned flyby of the Statue of Liberty was canceled as a result of damage to the covering on the left wing. But air traffic control had blocked all other flights for the landing; Solar Impulse 1 was placed on public display. In August 2013, it was disassembled and transported back to Dübendorf Air Base, where it was placed in storage in a hangar. During the American flights, a new partner had joined them: Google.
Solar Impulse 1 had always been considered as a prototype for a round-the-world airplane. No. 2 was designed and built following lessons learned during the above flights. It would use 140 carbon-fiber ribs with a gap of 50 cm (20 in.) intervals, in order to provide wingspan rigidity. With a length of 22.4 m (73.5 ft.) and a wingspan of 71.9 m (236 ft.), and a weight of only 5,000 pounds (2,268 kg), the solar airplane carried 17,248 monocrystalline silicon solar cells, 135μ thick and mounted on the wings, fuselage and horizontal tail plane. She had more powerful brushless, sensorless engines, 13 kW (17.4 hp). Her lithium-polymer batteries, manufactured by Kokam, had been optimized to have a density of 260 Wh/kg, capable of storing 164,580 watts of power. With a total mass of 633 kg (2,077 lb.), the batteries would store power needed to allow the aircraft to fly during nights.
Construction had begun in 2011, with completion initially planned for 2013, with a 25-day circumnavigation of the globe planned for 2014. But a structural failure occurred on the aircraft’s main spar during static tests in July 2012, and it exploded when they reached 100 percent of the load. This led to delays in the flight testing schedule to allow repairs. Solar Impulse 2HB-SIB was first publicly displayed on April 9, 2014, at Payerne Air Base, while her first flight, with Markus Scherdel at the controls, took place on June 2, 2014. The aircraft climbed to a randomly orbiting path within a 20-mile (32 km.) compass of the airfield to the southwest, Lake Neuchatel to the north, and Belleville to the northeast. It averaged a ground speed of 30 knots (56 km/h) on the 2-hour flight, and reached an altitude of 5,500 feet (1,670 m).
The first night flight was completed on October 26, 2014, and the aircraft reached its maximum altitude during a flight on October 28, 2014. Flight testing was completed in 2014 and the aircraft was delivered to Masdar, Abu Dhabi, by a cargo plane for the World Future Energy Summit in late January 2015. Prince Albert of Monaco, His Excellency Dr. Sultan Al Jaber of the UAE, and Richard Branson joined Bertrand Piccard and André Borschberg to launch the FUTURE IS CLEAN movement one day before takeoff.
On March 9, 2015, Solar Impulse 2, with Borschberg at the controls, took off on its circumnavigation of the Earth, with the return to Abu Dhabi in August 2015. The route followed was entirely in the Northern Hemisphere. Seventeen stops were planned along the route; at each stop, the crew would have to wait for good weather conditions along the next leg of the route. A mission control center for the circumnavigation, directed by Raymond Clerc, was set up in Monaco, using satellite links to gather real-time flight telemetry and remain in constant contact with the aircraft and the support team.
2015: André Borschberg (left) and Bertrand Piccard discuss flying strategy in front of the Solar Impulse 2 (© Solar Impulse).
Departure was from Al Bateen Executive Airport Abu Dhabi in the United Arab Emirates. Destination: Muscat (Oman). This first 772-km (480-mi) leg took 13 hours 1 minute. In Leg 2 (1,593 km/990 mi), leaving the Sheikh Zayed Grand Mosque below and heading out across the Arabian Sea to Ahmedabad (India), Piccard took 15 hours 20 minutes, completing the longest distance ever flown by a solar airplane in aviation history. On March 18, Solar Impulse 2 took off from Ahmedabad’s Sardar Vallabhbhai Patel International Airport, flying 1,170 km (728 mi.) over the Ganges River to Varanasi (India), touching down after 13 hours 15 minutes. Onwards to Mandalay and its temples (Myanmar), another 1,536 km, which took 13 hours 29 minutes. On March 29 the flight from India over the Yangtze River and down to Chongqing International Airport (China) a distance of 1,636 km (1016 mi.), took 20 hours 29 minutes. It was vital to switch on the automatic pilot and take 20-minute naps or use yogic breathing techniques or other exercises to promote blood flow and maintain alertness. Flying above the mountainous provinces of Yunman and Sichuan required Piccard to perform a steep climb at the beginning of the journey, and due to continuous flying at high altitude, he had to wear an oxygen mask and to face temperatures of -20°C. Crosswinds in China caused weeks of delays. Following the 1,384-km (860-mi) flight from Chongqing (China) to Nanjing (China), taking 17 hours 22 minutes, Chinese President Xi Jinping gave the team a great welcome.
Borschberg has described the challenge of Leg 7:
This was the moment of truth for our entire project: the first time that I must fly solo for more than twenty-four hours. To fly Si2, you need very calm air and the air is never calm so you do not know if you are flying in updraft or downdraft; five days was the minimum duration and the weather forecast five or six days ahead is only 30% reliable. So what would the weather be like when I arrived over Hawaii, one single point in the middle of the ocean? It could also be the longest solo flight in the history of aviation—Steve Fossett had made a three-day flight, so we had always wanted to double his record. So I took off from China. As we got close to Japan, the weather worsened, forcing me to curtail the flight and land at Nagoya-Komaki airport until conditions improved. Despite this, by remaining airborne for 3 consecutive days and nights, Si2 had broken all distance and duration world records for solar aviation. As it happened, call it coincidence, on closer inspection in Japan, we discovered that one of the main electrical systems which provided power for the cockpit had a fault. Potentially this would have stopped working in the middle of the Pacific Ocean had I decided to press on. As Japan had not been on our schedule, it was difficult to find a hangar for our wingspan. We were grounded for one month, waiting day after day for the weather to clear. When eventually I did take off again, there were technical problems. Due to insufficient air cooling, our lithium batteries were overheating due to high climb rate and an over insulation of the gondolas. The engineers asked me to return to Japan where they could be fixed. When I announced that I was not intending to do so, this created a huge emotional crisis. I had to have full conferences from the cockpit because people were threatening to resign. It was incredibly fraught. It was at times like this that yoga was vital and cat naps proved vital.6
Borschberg ran the risk. After 8,924 km (5,545 mi) across the Pacific, a grueling 4 days 21 hours 52 minutes in the air, the Swiss co-pilot touched down at Kalaeola Airport, Oahu, Hawaii. Here it was decided that, until the battery problem had been solved, they would winter on the volcanic island. This meant they would miss their “weather window” to cross the Atlantic before the end of 2015. The team also faced financial troubles in 2015 after raising €20 million from sponsors. While they were waiting, in November 2015, Piccard and Borschberg attended the COP 21 in Paris, where they met U.S. President Barack Obama, confidently inviting him to see Solar Impulse 2 in the USA the following year. Bertrand Piccard was also designated the United Nations Environment Program
(UNEP) Goodwill Ambassador. Meanwhile, in Hawaii, the team had replaced the batteries and installed a new integrated cooling system. Between February and mid–April 2016, some thirteen test flights were carried out to ensure proper functioning, as well as training flights for Piccard and Borschberg. In addition, to give them more flexibility for route planning, they lined up four potential destinations: Phoenix, San Francisco, Los Angeles and Vancouver.
2014: Solar Impulse 2, in flight (© Solar Impulse).
Flights resumed on April 21, 2016. Piccard left Hawaii behind him and, after 2 days 17 hours 29 minutes in the air, covering 4,523 km (2,810 mi), he arrived in the USA.
On April 22, while flying over the Pacific, he spoke directly from the cockpit of Si2 to United Nations Secretary-General Ban Ki-Moon at the UN in New York, where 175 nations had just signed the Paris Agreement on Climate Change. Piccard commented, “If an airplane like Solar Impulse 2 can fly day and night without fuel, the world can be much cleaner.” There was another iconic moment when the solar airplane flew over Golden Gate Bridge, at what appears to be about 3,000 feet (900 m). It was dark by the time the experimental craft made it down the peninsula to Mountain View, touching down at Moffett Airfield, operated by Google, one of the Si2’s sponsors. Google’s Planetary Ventures are nearby, as well as NASA’s Ames Research Center.
All this time, “internauts” had continued to watch the flight “live” via the website solarimpulse.com and followed the experience in real time thanks to 5 onboard cameras, as well as one showing Mission Control. For most of its time airborne, Solar Impulse 2 would cruise at a ground speed of between 50 and 100 kph (30 and 60 mph), usually at the slower end of that range at night to save power.
From the West Coast, the European sun-plane now took 15 hours 52 minutes to cover the 1,199 km (745 mi) to Phoenix Goodyear Airport, then on to Tulsa, passing over Missouri, Illinois, and Indiana, and then to land, as gracefully as usual, after dark, its sixteen headlights lighting the runway at Dayton International Airport, Ohio, home of the Wright Brothers, another flight of over one thousand kilometers taking over sixteen hours. After landing, pilot André Borschberg was met by two relatives of the Wright Brothers, neither of whom ever married: great-grandnephew Stephen Wright and great-grandniece Amanda Wright Lane. They gave models of the Wright Flyer to both Borschberg and Piccard, “the Solar Brothers.” Piccard noted that Dayton had served as the base for Orville and Wilbur Wright’s airplane-building operation more than a century ago. He told a crowd of onlookers in Dayton, “People told the Wright Brothers, and us, what we wanted to achieve was impossible. They were wrong. If everything goes well, we’ll land in Abu Dhabi in July this year and in 10 years’ time, there will probably be electric airplanes.”
April 23, 2016: After its flight from Hawaii, Solar Impulse 2 flies over the Golden Gate Bridge (©Solar Impulse).
On May 25, Solar Impulse 2 continued its silent and globally followed flight across the United States, reaching Lehigh Valley, Pennsylvania, and then on to New York, a shorter hop of 230 km (142 mi) taking just 4 hours 41 minutes. Borschberg ended this leg by circling the Statue of Liberty and flying in front of the skyline of Manhattan, touching down at JFK at 7:59 a.m. During Si2’s stay, it was visited by Ban Ki-Moon, sponsors and their personnel, and 500 children.
On June 20, 2016, Bertrand Piccard took off from New York City and headed out over the Atlantic Ocean on one of the toughest stages of their attempt to fly around the globe using solar energy. Meditation, hypnosis and short naps would again play a vital role during a flight lasting almost four days. In fact, thanks to nine days of meticulous work from the Mission Control Center in Monaco and their weather specialists, they were able to identify a narrow window, bypassing a cold front that was situated in the middle of the Atlantic; the 6,765-km (4,203-mi) flight took only 2 days 23 hours 8 minutes. During the flight, Piccard announced the intention to create an NGO, the International Committee for Clean Technologies (ICCT). Its goal: to continue the legacy Solar Impulse started, promoting concrete energy efficient solutions in order to solve many of the challenges facing society today.
Touchdown was at 5:38 a.m. in Seville, Spain, and as he prepared to land, Piccard was welcomed by the Spanish Patrulla Águila, and then, once on the tarmac, by Borschberg. “Charles Lindbergh completed the first transatlantic flight in 1927 from New York to Paris, and now Bertrand has brought aviation to the next level with clean technology. I bet you Lindbergh never imaged a solar airplane could do the same!”
Now it was the 64-year-old Borschberg’s turn. His final flight, to Cairo, was his chance to break the late Steve Fossett’s 2006 absolute world record for “speed around the world, non-refueled.” He took off on July 11 in the pre-dawn darkness from Seville, crossed the Mediterranean through the airspaces of Tunisia, Algeria, Malta, Italy, and Greece, taking 2 days 50 minutes to cover the 3,745 km (2,327 mi). As Si2 approached Cairo, Borschberg flew over the pyramids at sunrise. The ancient pyramids poked through the morning city mist, beautifully juxtaposing the solar-powered airplane that flew above. Borschberg: “To fly over the country of the great Pyramids reminded me that there was a time when the sun was worshiped as a god. These pyramids had been built for eternal life or sustainability which is also what we are trying to promote three thousand years later.”
For the final leg of this marathon circumnavigation, Leg 17, back to Abu Dhabi, Piccard was to take the controls. On July 15, the weather conditions were favorable, the plane was ready, but then 58-year-old pilot Piccard fell ill, forcing the historic flight to be postponed, because he could not possibly fly for 48 hours in that state. Mission Control identified a weather window that could allow Si2 to overcome the high temperatures across Saudi Arabia. Conditions were tricky with winds challenging Si2’s limitations on the runway. With Piccard recovered, the flight began across the Red Sea and past the Persian Gulf. To avoid the severe turbulence above the hot Saudi desert, he had to fly at high altitude: “There were moments in the last night that I could not rest at all, I just had to fight with my flight controls.”
But on Tuesday, July 26, 2016, Solar Impulse 2 touched down at Al Bateen Executive Airport, after 2 days 47 minutes of flying covering 2,694 km (1,673 mi). Climbing out to cheers and applause from team and spectators, Bertrand Piccard commented, “The future is clean. The future is you. The future is now. Let’s take it further.” Co-pilot Borschberg commented, “Now that Solar Impulse’s technology has demonstrated that unlimited endurance is possible for an airplane, I am keen to start developing future applications such as drones….”
By landing back in Abu Dhabi after a total of 23 days of flight and 43,041 km (26,744 mi) traveled in a 17-leg journey, with 4 continents, 3 seas, and 2 oceans crossed, Si2 had proven that clean technologies can achieve the impossible. Nineteen official FIA aviation records had been set during the global adventure, in particular the crossing of the Pacific and the Atlantic.
Ban Ki-Moon, the UN Secretary-General, said: “Solar Impulse has flown more than 40,000 kilometers without fuel, but with an inexhaustible supply of energy and inspiration. This is a historic day for Captain Piccard and the Solar Impulse team, but it is also a historic day for humanity.”
July 26, 2016, the victorious Solar Impulse team at Abu Dhabi’s Al Bateen Executive Airport (©Solar Impulse).
The Swiss post office released a special 100-franc stamp to mark the achievement.
On November 11, 2016, the Solar Impulse Foundation launched the World Alliance for Clean Technologies during COP22 at Marrakech, as a legacy to the first-ever solar flight around the world. Its goal is to federate the main actors in the field of clean technologies, in order to create synergies, promote profitable solutions to the world’s most pressing environmental and health challenges, and give credible advice to governments. During COP23 in Bonn, the WACT announced its goal of selecting 1,000 solutions that can protect the environment in a profitable way, and bring them to decision makers at COP24 to encourage them to adopt more ambitious environmental targets and energy policies.
One can only wonder what the ghosts of electric airplane pioneers, such the Tissandier brothers in the 1880s, Fred Militky in the 1970s, Paul MacCready in the 1980s, and other brave spirits might have thought about a flight which had attracted the attention of the whole world.7
In February 2017, the 460-page Objectif Soleil: L’aventure Solar Impulse (Objective Sun: The Solar Impulse Adventure), with Piccard and Borschberg as contributors, was published by Stock. On June 17, as part of the National Geographic Explorers Festival, Piccard and Borschberg were awarded the 2017 Further Award in recognition of their pioneering solar-powered flight around the world.
André Borschberg has commented:
The Solar Impulse airplane is not ready for retirement after our round-the-world mission. It has been designed to fly a total of 2,000 hours. By the end of the mission, we will have only flown 700 hours, and therefore still have 1300 hours remaining. We are, therefore, considering using the plane for further testing on solar technologies with a test pilot to learn how to make the plane fully autonomous. The mistake made by people in the past was to take an existing airplane, get rid of the combustion engine replacing it with electric motors and test it. It makes less noise but you see the limits of the technology instead of the potential because the mileage is very small. Electric propulsion has a fantastic future, because it is highly efficient, quiet, reliable and easy to control. What you have to do is to build an airplane around this technology. I am starting a new VTOL project whose goal is to revolutionize air transport in cities. We are at a time when a lot of things are converging – what’s happening in cars, in battery technology, software solution, new materials is going to change things very soon.
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While Solar Impulse used solar panels for marathon flights, Jean-Luc Soullier, a former French airline pilot and holder of the world record in microlight electric propulsion (see Appendix C), plans to use fuel cells for his Etlantic microlight. In this, he has been helped by Roman Marcinowski, head of AéroSkyLux, a research laboratory for non-polluting energies based in Gap (Hautes-Alpes). Their fourth prototype, designed by Grégory Cole, is made of carbon, aluminum and titanium with a 50-ft (15-m) wingspan and will use a “de-turbulator” which reduces the energy consumption of flying craft today by 20 percent. The power supply for the 15 kW Rotex engine is supplied by 100 ft2 (10 m2) of solar panels and fuel cells that supply Li-Po batteries and then lithium-thionyl chloride batteries to achieve a speed of 110 mph (180 kph). Its 35 hours of autonomy of flight would allow Soullier to cover the New York–to–Paris transatlantic distance of 3624 miles (5,831 km). The Frenchman then plans to fly from London to Darwin, 8,602 miles (13,843 km), in 2018. One is reminded of the plans presented in the late 1880s by another Frenchman, Arthur DeBausset, as chronicled in Chapter One.
Also in France, with initial sponsorship from Paris Airports, Raphael Dinelli of Les Sables d’Olonne, an experienced offshore sail racer, has planned a translatlantic flight from New York to Paris Le Bourget in his solar-powered biofuelled Eraole. Dinelli and his team at the Océan Vital Laboratory have spent two years researching the best biofuel for the task, settling finally for an oil made from micro-algae, cultivated specifically for this purpose. The Eraole’s average speed of around 100 kilometers per hour means Dinelli will be stuck in its tiny cockpit for nearly 60 hours.8
Transoceans.fr, based at the Dôme Airpark, Le Champ Pres Froges, southeastern France, has also been planning a series of airship records. Firstly, a speed record with the transoceans Lelio, for a target 120 kph (75 mph). For Lelio’s design, transoceans resorted to services by the Laboratoire Aérodynamique Eiffel (Eiffel Aerodynamics Laboratory) and investigated Eiffel’s research work discussing airship profiles. They also used their partner Airstar’s wind tunnel for minor profile studies. For example, the pilot is positioned inside the envelope, leading to eliminating the nacelle. Following this, a second record is envisaged: a world record for the airship crossing of the Mediterranean Sea, and ultimately an Atlantic crossing by Stream Continental 1, this time using fuel cell propulsion. Cruising from 80 to 100 km/h (50 to 62 mph) it would take about sixty hours to cross the Atlantic Ocean. At the time of writing, transoceans has been held back due to lack of finance.