When astronaut Shubhanshu Shukla spoke with Prime Minister Narendra Modi about his time aboard the International Space Station (ISS), his most arresting revelation was enduring 16 sunrises and 16 sunsets each Earth day—an extraordinary spectacle that blurs the lines between dawn and dusk.
Vision of Eternal Dawn
Orbiting at 408 kilometers above the planet, the ISS completes an Earth circuit roughly every 90 minutes. This frenetic pace means a full sequence of sunrise and sunset occurs roughly every 45 minutes. From this vantage point, Earth’s horizon becomes a stage for rapid-fire light shows: fiery sun flares, glowing clouds, ocean reflections—each appearance unique.
Yet with beauty comes disruption. Natural circadian rhythms—tuned to a 24‑hour cycle—are overwhelmed by this rapid succession of light and dark. As Shukla told PM Modi, “It’s magical, but if you don’t rein it in, your sleep, appetite, even decision-making can unravel.”
Engineering the Night
To maintain mental and physical equilibrium, Shukla and fellow astronauts adhere to Earth-time schedules mapped to Coordinated Universal Time (UTC). Programmable LED lights throughout the station simulate dawn, mid-day, dusk, and night. These artificially controlled light cycles are essential: without them, the body’s internal clocks would spin out of synchronization, affecting hormone production, immune response, and sleep quality.
Routine Under Rapid Skies
Shukla described a day that resembles mission choreography:
- Simulated Morning: Light gradually brightens, mimicking sunrise. Crew members wake, follow hygiene routines, and consume rehydrated meals.
- Health Monitoring: Blood pressure, oxygen levels, bone metrics, and muscle mass are recorded regularly. The high frequency of sunrises magnifies disorientation, making physiological tracking vital.
- Science at Every Turn: Microgravity research—cell growth, physiological responses, materials science—dominates the schedule. Shukla shared a moment of solidarity with plant biology teams, proudly discussing experiments on seed germination in space.
- Maintenance Responsibilities: Systems checks on life support, air filtration, and propulsion are constant. On some days, spacewalks are necessary, requiring hours of preparation and precise execution.
- Shared Breaks: Communal meals reinforce camaraderie. Shukla, excitedly, described enjoying desi flavors prepared back on Earth and warming their spirits in orbit.
- Simulated Sunset: As Earth rotates beneath them, dimmed lighting cues the end of the day. The crew begins routines to relax: conversations, exercise, hobbies, or off-hours research.
- Sleep in Space: Floating in sleeping bags within individual compartments, astronauts drift off to the white noise of fans and hum of electronics. Maintaining sleep gets harder when 16 sunrises keep punctuating the night cycle.
Emotional Reflections
The speed of these celestial moments compresses time into a stream of marvels: oceans shimmering under sunlight, auroras glowing over polar regions, city grids flickering in night landscapes. Yet this constant change also amplifies the longing for stability. Shukla emphasized the importance of connection through video calls, personal traditions, and mindfulness breaks—strategies to mitigate the disorienting pace of life above Earth.
A School in the Sky
The ISS offers invaluable lessons for Earth-bound needs:
- Health Applications: Understanding bone loss and muscle atrophy helps develop treatments for osteoporosis and immobilization cases.
- Psychology of Isolation: Coping mechanisms forged by astronauts inform long-duration missions and mental-health practices in isolated settings—like remote research stations or submarines.
- Earth Observation: With unparalleled visual access, the ISS serves as a sentinel. “On one orbit, I watched a hurricane form and dissipate over a few passes,” Shukla shared—insights that feed into climate science and disaster response strategies.
Preparing for the Future
Shukla sees the ISS as a crucible prepping humanity for Mars and lunar missions. Tailoring lighting to simulate variable day lengths, designing routines robust to rapid time shifts, and crafting support systems for mental resilience are all key to future success. “If we can thrive on 16 sunrises a day, adjusting to Mars’ 24h39m cycle becomes just another calibration,” he said.
Honing a Habitual Life in Space
Both headlines unveil the deep interplay between the wonder and the grind of orbital life. Shubhanshu Shukla’s account strips away the glamour to reveal the science, structure, and spirit required to thrive under Earth’s twilight kaleidoscope. Every sunrise and sunset, no matter how fleeting, is both a reminder of home and a testament to human adaptability.