Satellites: orbital speed and period
Grade 11 Science Worksheet

Circle the best answer, or write your answer on the line.
Earth's GM is 398,600 km³/s² and its radius is 6371 km. At the low end of the ISS's range, 370 km up, what is the orbital speed to the nearest hundredth, Ari?
Earth's GM is 398,600 km³/s² and its radius is 6371 km. At the high end of the ISS's range, 460 km up, what is the orbital speed to the nearest hundredth, Bo?
Earth's GM is 398,600 km³/s² and its radius is 6371 km. For a model satellite 2000 km up, what is the orbital speed to the nearest hundredth, Esme?
The ISS's height varies between 370 and 460 km. How does its orbital speed change across that range, Jun?
- It is a little faster at 370 km
- It is a little faster at 460 km
- Its speed stays the same
Thin air drags on the ISS and slowly lowers its orbit. What must its engines do now and then, Kira?
- Boost it back up
- Nothing, since it rises again by itself
- Slow it down so it stays up
NASA gives the Moon's orbit a semimajor axis of 384,400 km. About how far does the Moon travel in one orbit, Milo?
- About 2.4 million km
- About 1.2 million km
- About 384,400 km
The Moon travels about 2,415,000 km per orbit in 27.32 days (NASA). What is its average speed, Noah?
- About 1.02 km/s
- About 0.01 km/s
- About 88,400 km/s, treating days as seconds
Why is the Moon's orbital speed, 1.022 km/s, so much lower than the ISS's, Pia?
- It is much farther from Earth's center
- It has no engines
- Earth's pull stops partway to the Moon
Why doesn't the satellite's own mass appear in v = √(GM ÷ r), Tala?
- Satellites have too little mass to count
- It cancels: the pull and the force needed both grow with it
- Mass doesn't matter in space
In v = √(GM ÷ r) for a satellite around Earth, what is M, Zee?
- Earth's mass
- The Moon's mass
- The satellite's mass