Space – Medium Level – GK Questions

Q: Which stage of PSLV uses solid propellant?

First and third stages – PSLV is a four-stage vehicle alternating between solid and liquid propulsion. The first (PS1) and third (PS3) stages use solid propellants, while the second (PS2) and fourth (PS4) use liquid propellants.

Q: The Oort Cloud is theorized to be the source of which type of comets?

Long-period comets – The Oort Cloud is a hypothetical spherical shell of icy objects surrounding the solar system at distances up to 100,000 AU. It is believed to be the reservoir of long-period comets.

Q: The Space Applications Centre (SAC) of ISRO, focusing on satellite payload development, is located in _______.

Ahmedabad – SAC is located in Ahmedabad, Gujarat. It designs and develops payloads for communication, navigation, and remote sensing satellites.

Q: India became which numbered country/agency to successfully reach Mars orbit on its first attempt?

First – With Mangalyaan's success in 2014, ISRO became the first space agency in the world to reach Mars orbit on its maiden attempt. Previous attempts by USA, USSR, and others had failures before success.

Q: Europa, a moon of Jupiter, is believed to have a subsurface ocean beneath its icy crust.

True – Scientific evidence strongly suggests Europa harbors a global saltwater ocean beneath its ice shell, making it a prime target in the search for extraterrestrial life.

Q: Which space agency operates the Gaia mission to map over a billion stars in the Milky Way?

ESA – Gaia is a space observatory of the European Space Agency (ESA), launched in 2013. Its goal is to create the most precise three-dimensional map of our galaxy.

Q: Which Indian satellite was the first to be placed in geostationary orbit by an indigenous launch vehicle?

APPLE – APPLE (Ariane Passenger Payload Experiment) was India's first experimental geostationary communication satellite, launched in 1981 aboard an Ariane rocket. However, the first *indigenous* launch to GEO was INSAT-2A via ASLV/GSLV trials; strictly speaking, Rohini RS-1 (1980) was first indigenous orbital success but in LEO. For GEO specifically via Indian vehicle, later missions achieved this. Note: APPLE was foreign-launched; Rohini was LEO. This question tests nuanced understanding.

Q: The Semi-Cryogenic Engine being developed by ISRO uses _______ as fuel and Liquid Oxygen as oxidizer.

Kerosene (RP-1) – ISRO's Semi-Cryogenic Engine uses refined kerosene (RP-1) as fuel and LOX as oxidizer. It offers higher thrust and density compared to cryogenic engines, intended for future heavy-lift vehicles like NGLV.

Q: Red stars are hotter than blue stars.

False – In stellar classification, blue stars are the hottest (surface temperatures > 30,000 K), while red stars are the coolest (surface temperatures < 3,500 K). Color indicates temperature via Wien's displacement law.

Q: What was the primary reason for the failure of Chandrayaan-2's Vikram lander to achieve a soft landing?

Communication loss due to hard landing – During the final descent phase on September 7, 2019, Vikram deviated from its intended trajectory and experienced a hard landing, resulting in loss of communication. The orbiter, however, continues to function successfully.