About Atmospheric Perturbations around the Eclipse Path (APEP) mission
- The mission will involve launching three rockets equipped with scientific instruments.
- Objective: To know how the upper atmosphere will change during the eclipse, especially the moment when there would be a sudden reduction in light.
- During an eclipse, the sudden drop in sunlight causes changes in the ionosphere, creating waves that ripple through this atmospheric layer.
- It will measure changes in electric and magnetic fields, density, and temperature.
- This launch will take place at the White Sands Missile Range in New Mexico, with a specific focus on the ionosphere.
- According to NASA, the ionosphere’s temperature and density are projected to decrease during the eclipse, resulting in a wave-like disturbance that has the potential to disrupt GPS and other satellite communications.
The process:
- The rockets will be positioned just outside the path of annularity, where the Moon moves directly in front of the Sun. Each rocket will deploy four small scientific instruments designed to record changes in electric and magnetic fields, density, and temperature.
- NASA’s goal is to achieve the first-ever simultaneous measurements from multiple locations in the ionosphere during a solar eclipse.
- Rockets can be launched precisely at the right moment and can investigate lower altitudes inaccessible to satellites.
- Sounding rockets were chosen by the team due to their ability to pinpoint and measure specific regions of space with great accuracy.
- These rockets can also record changes occurring at various altitudes as they ascend and descend from suborbital flights.
- The rockets will gather data at altitudes ranging from 45 to 200 miles (70 to 325 kilometres) above the Earth’s surface along their flight path.
Q1: What is ionosphere?
The ionosphere is a region of Earth’s upper atmosphere that contains a high concentration of ions and free electrons. It starts approximately 48 kilometers above the Earth’s surface and extends upwards to several hundred miles (about 1,000 kilometers). The ionosphere plays a crucial role in various atmospheric and radio propagation phenomena, including the reflection and refraction of radio waves.
Source: Indian-origin NASA scientist to lead rocket mission to‘ring of fire’ eclipse. Explained
Last updated on August, 2026
→ UPSC Mains 2026 will be conducted on 21st, 22nd, 23rd, 29th and 30th August 2026.
→ Check out the latest UPSC Syllabus 2026 here.
→ UPSC Mains Admit Card 2026 is expected to be released in early August at upsc.gov.in or upsconline.nic.in
→ Enroll in Vajiram & Ravi’s UPSC Mains Test Series 2027 for structured answer writing practice, expert evaluation, and exam-oriented feedback.
→ Join Vajiram & Ravi’s UPSC Mentorship Program 2027 for personalized guidance, strategy planning, and one-to-one support from experienced mentors.
→ Go through the UPSC Mains Previous Year Papers to enhance your preparation.
→ Download UPSC Mains Essay Paper 2025, UPSC Mains GS Paper-I 2025, UPSC Mains GS Paper-II 2025, UPSC Mains GS Paper-III 2025, UPSC Mains GS Paper-IV 2025, UPSC Mains English (Compulsory) Paper 2025, UPSC Mains Hindi (Qualifying) Paper 2025 here.
→ UPSC has released UPSC Toppers List 2025 with the Civil Services final result on its official website.
→ UPSC Calendar 2027 has been released.
→ Also check Best UPSC Coaching in India







