---
title: "A group of astronauts in a spaceship are attempting to land on Mars. As they approach the planet, they begin to plan their descent to the surface."
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url: "https://nerd-notes.com/ubq/30448/"
date_modified: "2025-11-20T00:26:59+00:00"
---

# A group of astronauts in a spaceship are attempting to land on Mars. As they approach the planet, they begin to plan their descent to the surface.

A group of astronauts in a spaceship are attempting to land on Mars. As they approach the planet, they begin to plan their descent to the surface.

**Part a)** Before the spaceship can land on Mars, it must enter a stable “parking orbit” above the planet. Derive an equation to find the orbital speed of the rocket (with a mass \( m \)), at a height \( h \) above the surface of Mars (with a mass \( M \) and a radius \( R \)). *(3 points)*

**Part b)** Two of the astronauts are trying to determine \( g \) at height \( h \) above Mars. Astronaut A says that \( g \) depends only on the mass of the spaceship, while Astronaut B argues that it depends only on the orbital radius, \( r = R + h \). Which aspects of each astronaut’s reasoning are correct AND incorrect? Explain your reasoning for both. *(3 points)*


*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/30448/*