Question

Helios – B spacecraft had a speed of 71 km/s when it was 4.3 × 10⁷ km from the sun. Its orbit is

• A. Circular
• B. Helical
• C. Elliptical
• D. Parabolic.

Answer 1

Answer: (C)

Elliptical

Answer 2

v₀ = $\sqrt { \frac { \mathrm { GM } } { \mathrm { R } } } = \sqrt { \frac { 6.67 \times 10 ^ { - 11 } \times 2 \times 10 ^ { 30 } } { 4.3 \times 10 ^ { 7 } \times 10 ^ { 3 } } }$ = 56 km/s since v > v₀, but < v_e, therefore, orbit is elliptical.