The Sky Becomes a Sunlit Launchpad: Switzerland’s Solar-Propelled Marvel Rises Past 9 500 m
First Light Ascent, Second Life Record
While dawn’s rays were still kissing the peaks of the Valais Alps, Raphael Domjan pushed his throttle forward. By the time ordinary traffic controllers switched shifts, the SolarStratos aircraft had already slipped above 31 000 ft, brushing the stratosphere and rewriting an altitude benchmark that had resisted challenge for one and a half decades.
Numbers in Thin Air
- New certified ceiling: 9 521 m – 31 237 ft
- Previous record: 9 235 m – 30 298 ft, set fifteen years ago
- Operational heart: Photovoltaic cells feeding twin electric motors
- Departure field: Sion Airport, southwest Switzerland
- Launch window: Tuesday morning, leveraging powerful mountain thermals
Climb Strategy: Riding Sun-Baked Air
Domjan did not brute-force his way into the record books. Instead, he allowed warm alpine updrafts to spiral his craft higher while the solar cells steadily converted daylight into the thrust needed to stay aloft. Every metre gained meant thinner air and less drag, turning the plane’s minimal propulsion budget into a quiet ascent that left nothing but a faint contrail.
A Quote to Remember
The mission headquarters offered a simple salute to the moment:
“This is not just an altitude reading; it is a memory etched at rarefied heights that marks the summit of both human courage and clean technology.”
Next Chapter
For now, the team will study data, refine batteries, and prepare future stratospheric campaigns. One point is already clear: the skies have a new, sun-powered milestone—and a pilot determined to keep raising it.
SolarStratos Soars: A Dawn-Era Glimpse of Carbon-Free Flight
At sunrise on 8 August 2025, silent rot blades cut the alpine fog as Raphael Domjan lifted the Swiss-built SolarStratos from Sion Airport. For the next five hours and nine minutes, the electric heartbeat of the sun powered every meter of his climb toward 10 000 meters—a height normally ruled by jet-driven giants.
High-Altitude Encounter
Halfway through the flight Domjan crossed contrails with a commercial Airbus. Passengers in cabin row 18 may not have noticed the winged silver sliver gliding in the opposite direction, yet SolarStratos later hailed the moment as a living vision of tomorrow’s decarbonized skies.
Why 10 000 Matters
- Psychological gate—the altitude at which airline traffic thins and the sky turns indigo.
- Technical gate—air density drops sharply, demanding redesigned wings and pressure-hull integrity.
- Regulatory gate—the World Air Sports Federation will soon scrutinize corrected pressure-density figures to certify the record.
Aircraft at a Glance
HB-SXA SolarStratos
Fuselage: 9.6 m of hand-laid carbon-fiber skin.
Wings: 24.8 m span—more room than most living-room ceilings—wrapped in 22 m² of second-generation photovoltaic cells.
Pace: 50 km/h lift-off, 140 km/h peak, 80 km/h steady cruise.
Propulsion: single nose-mounted propeller drawing silent electricity straight from the sky.
Beyond Today’s Ceiling
Even as the plane kissed 10 000 m, minds already wander another two kilometers higher to the stratosphere. Swiss skies see that boundary at approximately 12 000 m. Breaching it will push every solar cell, battery, and airframe curve to its limit—yet the team insists that the real win is not the kilometer, but the imagination earned.
What Comes Next
Flight logs, telemetry, and GPS traces have been forwarded to the Fédération Aéronautique Internationale. While judges crunch atmospheric corrections, engineers at Sion tighten wing ribs and software thresholds for the next climb—one that could see a lone pilot wearing a pressure suit meet the sun from 12 km above the world.
“Tomorrow can be better than what we have today”
At 6,589 meters, a Quiet Revolution Took Wing
In July 2024 a slender silhouette climbed above the French pre-Alps, unnoticed by commercial traffic below. It reached 6,589 meters—more than a kilometer higher than its designers thought possible for this season’s airframe. For the pilot glancing over an almost-empty energy gauge, the reading was proof that a childhood fantasy could mature into measurable fact.
From Water to Sky: The Prequel
Twelve years earlier the same dreamer had slipped out of Miami harbor aboard a slim catamaran with black wings for sails. Between 2010 and 2012 what looked like a fragile toy became the first surface craft to trace a full, unassisted circuit of the planet driven only by sunlight. The voyage served less as spectacle than as rehearsal; the captain, Raphaël Domjan, spent nights on the open Atlantic muttering “If it can carry me across salt water, it must be able to lift me into thinner air.”
What Was Proved on Water
- 100 % renewable propulsion under every weather regime known to sailors
- Continuous power autonomy for 585 days without refueling
- No engine noise, no bilge residue, zero fossil assistance in ports
- A public captivated not by danger but by the lack of it
Why the Sky Next?
When journalists asked why he would leave ocean stability for gusty uncertainty, Domjan offered a single reason older than writing itself: “People once believed only gods had wings.” By swapping sails for solar cells no thicker than a credit card, he intends to place human ambition back in human reach while quietly removing carbon monoxide from the equation.
Messages Hidden in the Altitude Record
- Altitude is a metaphor. 6,589 m is simply one more step on an infinite energy staircase.
- The young are the payload. The aircraft’s cockpit intentionally fits a student backpack behind the pilot so classrooms can later replicate the flight in simulators built from open-source data.
- Silence is part of the technology. The lack of engine roar lets observers below hear only wind, turning spectatorship into an emotional bond rather than a technical report.
- Improvement is democratic. Every kilowatt gleaned from the aircraft’s new gallium-arsenide skin last month was generated with components commercially available today.
The Next Thermals
Behind every milestone sits humility; Domjan talks less about triumph and more about calibration. Meteorologists already route polar air-mass data to the hangar, because an Antarctic leg is envisioned where daylight lasts twenty-four continuous hours yet temperatures freeze lithium ions in minutes. Engineers meanwhile swap ballast sacks for phase-change salt canisters that melt in daylight and release heat after sundown—an airborne twin to the thermal-storage hulls that once kept his solar catamaran steady during night crossings.
When the final logbook closes, the adventurer insists it will record not a record but an invitation—that one generation from now no teenager will think “flight” is synonymous with “kerosene”, and no city skyline will sound like an airport runway. Somewhere between sea level and 6,589 meters, the oldest human dream traded its roar for a whisper and kept on climbing.
SolarStratos Soars Toward the Sun—But the Sky Keeps Testing Its Limits
The Take-off Moment
With an unmistakable thumbs-up, Swiss aviator Raphael Domjan signaled to ground crews that the season’s first record-breaking run was on. At Sion Airport, high in the Valais Alps, the two-seat demonstrator rolled onto the runway at dawn on 8 August 2025, its 22-metre wing shimmering with photovoltaic panels.
An Aborted Friday, a Sunday Stand-in
Forty-eight hours earlier the same aircraft had taxied hopefully to the threshold, only for mission controllers to scrub the attempt when rising thermals—the invisible elevators SolarStratos relies on—never arrived. By standing down, the team safeguarded precious watt-hours stored in the lithium-polymer pack, redirecting them instead to Sunday’s do-over.
How the Mission Works
- Phase 1 – Thermal Boost: Domjan circles inside naturally occurring rising currents, spiralling up to roughly 4,500 metres.
- Regeneration at Altitude: Once above the cloud-build layer, the batteries absorb direct sunlight for up to one hour before the second ascent.
- Phase 2 – Power Climb: Propeller drive takes over, pushing the craft toward the 10 kilometre target stratum.
- A Mandatory Reserve: Landing must be made under full electric control, with no gliding dead-stick, and at least 16 % battery life intact.
Latest Figures From the Flight Deck
At press time SolarStratos had reached 8,224 metres—still short of the decade-old milestone—but well above the benchmark set by André Borschberg’s Solar Impulse 1 back in 2010. Telemetry shows power drawn at 7,620 m was less than forecast, an indication that thinner air is already easing propulsive demand.
Keeping It Purely Solar
Every amp supplied since engine start has been harvested from the 22 square metres of photovoltaic skin mounted across the wings and horizontal stabilisers. Regulators at the Fédération Aéronautique Internationale will disqualify any log containing auxiliary ground-charging or drop-tank assistance.
What’s Next
Ground team meteorologists now pore over forecast models for the next clear slot. Their aim: a sky offering both intense sunshine and strong thermal activity—the rare dual requirement that may finally carry the emerald-white airframe beyond five-digit height and into the history books.
