Satellites — Set 3
Technology · उपग्रह · Questions 21–30 of 50
Which satellite was India's first dedicated multi-wavelength space observatory?
Correct Answer: C. Astrosat
• **Astrosat (2015)** = India's multi-wavelength space observatory. • **X-ray/optical/UV observations** — simultaneous cosmic phenomena study; elite space telescope member. • 💡 Wrong-option analysis: A (Chandrayaan-1): lunar orbiter; B (Resourcesat): earth mapping; D (Aditya-L1): solar observatory.
How many satellites are required at minimum to determine a precise 3D position on Earth using GPS?
Correct Answer: D. Four
• **Four satellites minimum** = calculate latitude, longitude, altitude, time. • **Trilateration principle** — 3 satellites give 2D; 4th resolves time offset for 3D accuracy. • 💡 Wrong-option analysis: A (one): insufficient distance measurements; B (two): only 2D rough estimate; C (three): cannot determine time error.
Which of the following is the largest artificial satellite currently orbiting Earth?
Correct Answer: A. International Space Station
• **ISS characteristics** = habitable lab; football-field-sized; visible to naked eye from Earth. • **Continuous occupation** — humans since November 2000; LEO at ~400 km. • 💡 Wrong-option analysis: B (Hubble): space telescope, not habitable; C (Envisat): earth observation; D (GOES-16): weather satellite.
What is the primary purpose of 'OceanSat' satellites?
Correct Answer: D. Studying ocean biological parameters
• **OceanSat mission** = ocean physical/biological parameter measurements from space. • **Key parameters** — sea surface temperature, chlorophyll, wind vectors; vital for fisheries. • 💡 Wrong-option analysis: A (underwater volcanoes): not satellite detectable; B (internet): communication; C (sunken ships): sonar, not satellite.
Which country developed the GLONASS navigation satellite system?
Correct Answer: C. Russia
• **GLONASS system** = Russia's global navigation satellite system; alternative to GPS. • **Full coverage (2011)** — combined with GPS in modern phones for better accuracy. • 💡 Wrong-option analysis: A (USA): GPS provider; B (EU): Galileo system; D (China): BeiDou system.
What happens to a satellite when its mission ends in Geostationary Orbit?
Correct Answer: A. It is moved to a 'Graveyard Orbit'
• **Graveyard orbit** = parking zone above GEO for defunct satellites. • **Collision prevention** — protects active GEO band from debris interference. • 💡 Wrong-option analysis: B (burned): requires atmospheric entry velocity; C (brought back): too expensive; D (falls into Sun): gravity prevents this.
Which Indian satellite was the first to use an indigenous launch vehicle, SLV-3?
Correct Answer: C. Rohini (RS-1)
• **Rohini RS-1 (1980)** = first Indian satellite on indigenous SLV-3 rocket from Sriharikota. • **Space club milestone** — India became 6th nation with independent launch capability. • 💡 Wrong-option analysis: A (Aryabhata): Soviet rocket launch; B (Bhaskara-I): Soviet launch; D (Apple): GSAT-1 technical name.
Which frequency band is most commonly used by modern satellite-based internet services like Starlink?
Correct Answer: D. Ku-band
• **Ku-band frequency** = high-speed satellite communications and DTH television. • **Bandwidth advantage** — higher than L-band; rain fade susceptibility trade-off. • 💡 Wrong-option analysis: A (L-band): lower frequency, less bandwidth; B (VHF): terrestrial; C (AM): radio/broadcast.
What is a 'Nanosatellite' typically defined as?
Correct Answer: D. A satellite weighing between 1 kg and 10 kg
• **Nanosatellite definition** = 1–10 kg; often CubeSat format. • **Cost-effective access** — enables universities and small nations to conduct space research. • 💡 Wrong-option analysis: A (atomic scale): far too small; B (atmosphere): would burn up; C (nanotechnology only): studies can vary.
Which satellite provided the first-ever close-up images of Mars for India?
Correct Answer: D. Mars Orbiter Mission (Mangalyaan)
• **Mangalyaan (2013)** = India's first Mars mission; first-attempt orbit entry. • **Mars Colour Camera** — studies surface and atmosphere; world-record achievement. • 💡 Wrong-option analysis: A (Chandrayaan-1): lunar mission; B (Resourcesat): earth observation; C (Gaganyaan): human spaceflight.