Question

Which of the following statement(s) is/are CORRECT for sun-synchronous Earth observation satellites?

• A. They are in near-polar orbit around the Earth
• B. They cross the equator at different longitudes at nearly the same local solar time
• C. They maintain nearly the same sun–target–satellite geometry while crossing the equator at different longitudes
• D. The angle of inclination of their orbit is $<1^\circ$

Hint:

Sun–synchronous $⇒$ near-polar retrograde orbit with nodal precession tuned to keep constant {local solar time} at equator crossings; this preserves illumination geometry across revisits.

Answer 1

The Correct Option is A

(A) True. Sun–synchronous orbits are near-polar (inclination $\approx 97$–$99^\circ$) so the orbital plane precesses with Earth’s revolution to keep constant local solar time.
(B) True. By design, the orbital plane precesses $\approx 1^\circ$/day to match Earth’s mean motion around the Sun, so each equator crossing occurs at (nearly) the same local solar time though at different longitudes on successive passes.
(C) True. The constant local time-of-day ensures nearly constant illumination geometry (Sun angle), hence nearly the same sun–target–satellite geometry for observations at different longitudes/days.
(D) False. The inclination is not $<1^\circ$; it is close to $98^\circ$ (retrograde near-polar).
\[ \boxed{\text{Correct statements: (A), (B), (C); (D) is false.}} \]