Escape velocity, in astronomy and, the that is sufficient for a body to escape from a gravitational centre of attraction without undergoing any further. Escape velocity decreases with altitude and is equal to the of 2 (or about 1.414) times the velocity necessary to maintain a circular orbit at the same altitude. At the surface of the, if atmospheric resistance could be disregarded, escape velocity would be about 11.2 km (6.96 miles) per second. The velocity of escape from the less massive is about 2.4 km per second at its surface. A (or satellite) cannot long retain an atmosphere if the planet’s escape velocity is low enough to be near the average velocity of the gas molecules making up the atmosphere.

In early 2018, made headlines by, playing David Bowie’s “Starman” on repeat as it made its slow journey through space. This was a fun publicity stunt.

But how the Roadster got to space is an even cooler story.The Roadster hitched a ride on the newest SpaceX rocket, the, as it made its maiden voyage into space. At the time of its launch, the Falcon Heavy was the most powerful operational rocket in the world (though not in history).Did you know?The Falcon Heavy weighs almost 1.5 million kilograms! Diagram showing the relationship between escape velocity and the radius of the planet, the mass of the planet and Newton’s universal constant of gravity (© 2019 Let’s Talk Science).The M in the equation represents the mass of the planet. Planets with more mass are harder to escape than planets with less mass. This is because the more mass a planet has, the stronger its force of gravity.

For example, when you watch footage of astronauts jumping on the Moon, it looks effortless. This is because the Moon’s mass (and therefore its gravity) is much less than Earth’s.Did you know?As of 2019, only 24 humans have ever reached escape velocity. They were the crews of the missions that flew to the Moon between 1968 and 1972.The r in the equation represents radius, which is the distance between the centre of the planet and the object that is trying to escape. In other words, radius is the distance between the centre of the planet and its surface. As an object moves away from the planet, the planet’s gravitational pull will have less of an influence on it. If the object moves far enough away, it feels almost no attraction. When this happens, the escape velocity will basically be zero!Finally, the G in the equation is a constant.

Nov 04, 2015  Escaping Earth's gravitational pull isn't all that easy. NASA's shuttle uses over 800,000 gallons of fuel to achieve 'escape velocity.' + + + + + + + +.

Specifically, it is Newton’s universal constant of gravity. For the moment, all you need to know is that we need this constant to make the equation work.

G is approximately equal to 6.67 × 10 –11 metres 3/(kg)(second) 2.Now, let’s plug in some numbers to determine the escape velocity from the surface of the Earth. For M, we use the mass of the Earth, which is approximately 5.97 × 10 24 kg.For r, since we are calculating the escape velocity from the surface of the Earth, we can use the Earth’s radius, which is approximately 6.37 × 10 6 m.We can now calculate the escape velocity for the Earth. Escape velocity equals the square roots of 2GM over r which equals the square root of 2 times 6.67 times ten to the minus eleven times 5.97 times ten to the twenty fourth over 6 378 000, which equals approximately 11.2 kilometers per second.You can calculate the escape velocity from any body in space as long as you know its radius and its mass. For example, using the above equation, we can calculate the escape velocity of the Moon. From its equator, the Moon has a radius of 1 738 km. It also has an estimated mass of 7.342 × 10 22 kg. This means that the Moon’s escape velocity is 2.38 km/s.

That is much less than the 11.2 km/s it takes to get off the Earth. In the future, perhaps rockets will be built on and take off from the Moon rather than from Earth! The escape velocity of Mars is 4.25 km.s.

The escape velocity of Earth is 11.19 km/s. The escape velocity of Venus is 10.36 km/s. The escape velocity of Mars is 5.03 km/s.

The escape velocity of Saturn is 36.09 km/s. The escape velocity of Uranus is 21.38 km/s. The escape velocity of Neptune is 23.56 km/s.

The escape velocity of Jupiter is 60.20 km/s.We’ve taken a first glimpse at the rocket science needed to get the Falcon Heavy (and a Roadster playing David Bowie) into space. All we need to do is accelerate the rocket to 11.2 km/s and point it upwards. As the scientists and engineers at SpaceX know well, acceleration and pointing the rockets are the hard part!Did you know?As of 2019, the most powerful rocket ever made was NASA’s Saturn V. It was the rocket used to get astronauts to the Moon in the 1960s and 1970s.

Connecting and Relating. Have you watched a rocket launch before?

Have you heard the launch team talk about boosters firing and boosters falling away? What do you think is the purpose of boosters?.

If you could launch something into space, what would you choose? Why?.Relating Science and Technology to Society and the Environment. What would be the advantage, from an escape velocity perspective, of sending spacecraft to Mars from the Moon or a space station?. What are the advantages and disadvantages of reusable rocket boosters like the Falcon Heavy compared to older rockets like the Saturn V for sending spacecraft beyond Earth orbit?. What would the advantages and disadvantages of launching spacecraft to the Moon or Mars from low Earth orbit (e.g., from the International Space Station) vs. From the surface of the Earth? Would the benefits outweigh the costs?.Exploring Concepts.

What is escape velocity? Is escape velocity actually a velocity? Explain. Siren cast. How does the size of planetary body impact on its escape velocity?.

Does there come a point where a mass is too large to get off the Earth? Explain.Nature of Science/Nature of Technology.Is the cost and risk of sending spacecraft beyond Earth orbit justified by the scientific gains?Media Literacy. What media you seen heard or read about the Falcon Heavy? What types of media were used by SpaceX to promote the lift-off event?

What audiences is the company targeting? How does the media from SpaceX differ from the media produced by NASA?. Does a media stunt such as launching a car into space help raise awareness of and support of space exploration?Teaching Suggestions.

This article and embedded video can be use for Physics and Space Science teaching and learning related to planetary science. Concepts introduced include rocket, escape velocity, mass (M), radius (r), center, distance and Newton’s universal constant of gravity (G). After reading this article, teachers could have students consolidate their understanding of escape velocity using a learning strategy. Ready-to-use Concept Definition Web reproducibles are available in and formats.

For a math and physics focus and follow-up to reading this article, teachers could have students calculate the escape velocity for the other planets, given their mass and radius measurements. Their answers could be checked using the graphic in the article titled Escape Velocities from Planets in our Solar System.