SATHEE: Space Science

Space Science

Sun → 99.86% mass of Solar System; age ≈ 4.6 bn yrs; core temp ≈ 15 million °C
Light year = 9.46 × 10¹² km; AU = 149.6 million km
Nearest star (after Sun): Proxima Centauri (4.24 ly)
Escape velocity Earth = 11.2 km/s; Moon = 2.4 km/s
Geostationary orbit height = 35,786 km (period = 24 h)
Polar orbit ≈ 500–800 km; useful for remote-sensing
Lagrange Point-1 (L1) → Sun-Earth grav balance; ideal for solar observatories (e.g., Aditya-L1)
Kepler’s 3rd law: T² ∝ R³ (T in yrs, R in AU)
Gaganyaan crew capsule mass ≈ 7,800 kg; 3 astronauts, 2026 target
ISRO = 1969; HQ = Bengaluru; chairperson = S. Somanath (as of 2024)
Mangalyaan (MOM) = 2013 → India 1st country to succeed 1st attempt
Chandrayaan-3 landing site = “Shiv Shakti Point” (69.37°S, 32.35°E)
Cryogenic engine fuel: Liquid H₂ + Liquid O₂
SSLV (Small Satellite Launch Vehicle) maiden flight: 2022
Blue Origin rocket: New Shepard; SpaceX crew: Dragon 2

Planets order:
My Very Educated Mother Just Served Us Noodles (Mercury- Venus-Earth-Mars-Jupiter-Saturn-Uranus-Neptune)
ISRO centres:
Vikas Saraswat In Liquid Uranium Rocket Satellite Centre → VSSC (Thiruvananthapuram); rest: Satish Dhawan → SHAR (Sriharikota)

Launcher	Payload to LEO (kg)	Notable Points
PSLV	3,800	“Workhorse”; 50+ consecutive successes
GSLV Mk III	10,000	Renamed LVM-3; human-rated for Gaganyaan
SSLV	500	72-hr turnaround, 3 solid stages

Mission	Year	Specialty
Chandrayaan-1	2008	1st Indian moon; discovered water molecules
Chandrayaan-2	2019	Orbiter 100% alive; Vikram lander hard-landed
Chandrayaan-3	2023	1st soft-landing near lunar south pole
Aditya-L1	2023	1st Indian solar observatory @ L1

1. Which Indian mission first confirmed water on the Moon?

A) Chandrayaan-1 **Ans: A**

2. Escape velocity of Moon is approximately?

A) 7.9 km/s B) 11.2 km/s C) 2.4 km/s **Ans: C**

3. LVM-3 was earlier known as?

A) PSLV-XL B) GSLV Mk III C) SSLV **Ans: B**

4. Lagrange point suitable for uninterrupted solar viewing is?

A) L2 B) L1 C) L4 **Ans: B**

5. The “Shiv Shakti Point” is associated with which landing?

A) Vikram (Ch-2) B) Pragyan (Ch-3) C) Vikram (Ch-3) **Ans: C**

6. 1 light year equals roughly?

A) 9.5 trillion km B) 1 million km C) 150 million km **Ans: A**

7. ISRO’s human spaceflight programme is named?

A) Gaganyaan B) Antariksh Yatri C) Bharatiya Astronaut **Ans: A**

8. Cryogenic engines use fuel combination?

A) UDMH + N₂O₄ B) Liquid H₂ + Liquid O₂ C) Kerosene + Liquid O₂ **Ans: B**

9. The PSLV launched its 50th mission from which spaceport?

A) Sriharikota B) Thumba C) Bengaluru **Ans: A**

10. Which planet is called “Red Planet”?

A) Venus B) Mars C) Jupiter **Ans: B**