UPSC Prelims Practice Questions — Eärendil-1: bright or blight?
Q1. The July 2026 FCC authorisation of Eärendil-1 rested primarily on which one of the following regulatory determinations?
- A. That the satellite's use of radiofrequency spectrum, together with its orbital debris profile, satisfied the Commission's requirements
- B. That the reflected sunlight would remain below an internationally agreed night-sky brightness threshold
- C. That the mission had cleared an environmental impact assessment covering night-time illumination of the ground footprint
- D. That the operator held a valid commercial launch licence for a near-polar low Earth orbit
Q2. Consider the following characteristics attributed to the Eärendil-1 satellite:
1. It carries a deployable 18 m × 18 m aluminized Mylar thin-film reflector.
2. Its reflector has an area of about 324 sq m and a mass of about 16 kg.
3. It is placed in a geostationary orbit so that it can dwell continuously over a chosen ground target.
4. It is designed to illuminate a ground patch about 5 km wide.
Which of the above is/are NOT correct?
- It carries a deployable 18 m × 18 m aluminized Mylar thin-film reflector.
- Its reflector has an area of about 324 sq m and a mass of about 16 kg.
- It is placed in a geostationary orbit so that it can dwell continuously over a chosen ground target.
- It is designed to illuminate a ground patch about 5 km wide.
- A. 1 and 2
- B. 2 and 4
- C. 1, 3 and 4
- D. 3 only
Q3. Consider the following design and orbital attributes:
1. An operating altitude of about 625 km
2. An orbital inclination of about 88 degrees, giving a near-polar path
3. A specular (mirror-like) reflecting surface rather than a diffusely scattering one
4. Complete absence of on-board propulsion, disposal being left entirely to atmospheric drag
Which of the above is/are correctly identified as attributes of Eärendil-1?
- An operating altitude of about 625 km
- An orbital inclination of about 88 degrees, giving a near-polar path
- A specular (mirror-like) reflecting surface rather than a diffusely scattering one
- Complete absence of on-board propulsion, disposal being left entirely to atmospheric drag
- A. 1 and 4 only
- B. 2 and 3 only
- C. 1, 2 and 3 only
- D. 1, 2, 3 and 4
Q4. Reflect Orbital's publicly stated long-term roadmap envisages an eventual constellation of approximately how many reflector satellites by 2035?
- A. 5,000
- B. 12,000
- C. 42,000
- D. 50,000
Q5. Reflect Orbital, a California-based venture, required an operating authorisation for its Eärendil-1 demonstration from which one of the following United States bodies?
- A. National Aeronautics and Space Administration (NASA)
- B. Office of Commercial Space Transportation of the Federal Aviation Administration
- C. Federal Communications Commission (FCC)
- D. Commercial Remote Sensing Regulatory Affairs office of NOAA
Q6. The Znamya-2 orbital mirror experiment of February 1993, which briefly reflected sunlight across a swath of Europe at night, was deployed from which one of the following?
- A. A Progress supply spacecraft after it undocked from the Mir space station
- B. The Kvant-2 module of the Mir space station
- C. A Soyuz-TM crew ferry in a free-flying phase
- D. The Salyut-7 space station
Q7. In the context of the 1993 Znamya-2 experiment, the term 'space mirror' referred to which one of the following?
- A. A 20-metre-diameter deployable thin film, thinner than a human hair, spun open in orbit to reflect sunlight onto the Earth's night side
- B. A rigid polished glass reflector used to concentrate sunlight on an on-board boiler for power generation
- C. An array of corner-cube retroreflectors used to track the orbit of the station by laser ranging from the ground
- D. A deployable shade used to shield a spacecraft's radiators and instruments from direct solar heating
Q8. Under the Outer Space Treaty, 1967, the obligation that activities of non-governmental entities in outer space shall require authorisation and continuing supervision by the appropriate State Party is laid down in which one of the following Articles?
- A. Article II
- B. Article IV
- C. Article VI
- D. Article IX
Q9. Which one of the following is the brightness threshold identified by the International Astronomical Union as the principal limit beyond which satellites significantly interfere with professional astronomical research?
- A. Apparent magnitude 2
- B. Apparent magnitude 6
- C. Apparent magnitude 7
- D. Apparent magnitude 12
Q10. Consider the following statements regarding the naming of the Eärendil-1 satellite and its literary source:
1. The satellite takes its name from Eärendil the Mariner, who in the source work bears light into the heavens and becomes the evening star.
2. That source work, The Silmarillion, differs from The Hobbit and The Lord of the Rings in having been published only after its author's death, edited by his son Christopher Tolkien in 1977.
3. Znamya, the name of the earlier Russian orbital-mirror experiment, is likewise drawn from the same literary legendarium.
Which of the statements given above is/are correct?
- The satellite takes its name from Eärendil the Mariner, who in the source work bears light into the heavens and becomes the evening star.
- That source work, The Silmarillion, differs from The Hobbit and The Lord of the Rings in having been published only after its author's death, edited by his son Christopher Tolkien in 1977.
- Znamya, the name of the earlier Russian orbital-mirror experiment, is likewise drawn from the same literary legendarium.
- A. 1 only
- B. 1 and 2 only
- C. 2 and 3 only
- D. 1, 2 and 3