About STEREO spacecraft:
- The pair of STEREO (Solar TErrestrial RElations Observatory) spacecraft were launched on October 25, 2006, from Florida’s Cape Canaveral Air Force Station.
- The two spacecraft were situated in Sun’s orbit, STEREO-A (“Ahead”) and STEREO-B (“Behind”).
- The dual-spacecraft mission accomplished its major goal by delivering the first-ever stereoscopic view of our star.
- On February 6, 2011, another significant milestone was achieved as both STEREO-A and -B reached a remarkable 180-degree separation in their orbits, which gave us the full sphere image of the Sun.
- Significance of STEREO-A
- It will synthesize its views with those from Nasa’s and the European Space Agency’s Solar and Heliospheric Observatory (SOHO) and Nasa’s Solar Dynamics Observatory (SDO).
- Its distance from Earth changes throughout the flyby, it will optimize its stereo vision for different-sized solar features at different times, akin to adjusting the focus on a several million-mile-wide telescope.
- It will allow scientists to understand how a coronal mass ejection’s (CME) magnetic field evolves on its way to Earth.
Q1) What is the heliosphere?
The heliosphere is a vast region of space surrounding the Sun where the solar wind, a stream of charged particles emanating from the Sun, interacts with the interstellar medium, which is the tenuous gas and dust that exists between stars in our galaxy.
Source: Spacecraft prepares for rare Earth flyby 17 years after it left planet
Last updated on June, 2026
→ UPSC Prelims Provisional Answer Key 2026 out for GS Paper 1 and CSAT.
→ UPSC Prelims Question Paper 2026 Out, Download GS Paper 1 PDF conducted on 24th May 2026.
→ UPSC Mains 2026 will be conducted from 21st August 2026 onwards, and UPSC Prelims 2027 will be held on 23rd May 2027.
→ Prepare effectively with Vajiram & Ravi’s UPSC Prelims Test Series 2027 featuring full-length mock tests, detailed solutions, and performance analysis.
→ UPSC Final Result 2025 is now out.
→ UPSC has released UPSC Toppers List 2025 with the Civil Services final result on its official website.
→ Anuj Agnihotri secured AIR 1 in the UPSC Civil Services Examination 2025.
→ UPSC Notification 2026 & UPSC IFoS Notification 2026 is now out on the official website at upsconline.nic.in.
→ UPSC Calendar 2027 has been released.
→ Check out the latest UPSC Syllabus 2026 here.
→ The UPSC Selection Process is of 3 stages-Prelims, Mains and Interview.
→ Enroll in Vajiram & Ravi’s UPSC Mains Test Series 2026 for structured answer writing practice, expert evaluation, and exam-oriented feedback.
→ Join Vajiram & Ravi’s Best UPSC Mentorship Program for personalized guidance, strategy planning, and one-to-one support from experienced mentors.
→ Shakti Dubey secures AIR 1 in UPSC CSE Exam 2024.
→ Also check Best UPSC Coaching in India







