STEREO Orbits

Challenge Answers

Part 1

The workings for orbital distance of each spacecraft are as follows.

(Please note that we have rounded our answers to 3 significant figures)

STEREO A

Orbital Period = 360/382 = 0.942yrs (this is ‘T’ below)

T² = 0.888 = a³

a = ³√0.888 = 0.961AU

1AU = 150,000,000km (93,000,000miles)

0.961AU = 144,150,000km (89,373,000miles )

This represents a distance of about 5,900,000km (3,600,000miles) closer to the sun than the Earth is.

STEREO B

Orbital Period = 360/338 = 1.065yrs (this is ‘T’ below)

T² = 1.134 = a³

a = ³√1.134 = 1.043AU

1AU = 150,000,000km (93,000,000miles)

1.043AU = 156,450,000km (96,999,000miles)

This represents a distance of 6,500,000km (4,000,000miles) further from the sun than the Earth is.