How high is the Sky?
Did you know that most people on Earth live closer to Space then they do to their countries capital? Space is only 62 miles (100 kilometers) away from you, in contrast Rhyl is 127 miles (205km) from Cardiff and 189 miles (304km) from London as the crow flies (Straight line distance). Mars is then at least 33.9 million miles (54.6 million km) away from the Earth.
So, why is it easier to get to London than Space?
If you wanted to walk to London you could do it one step at a time, eventually you would reach your destination. You can not do the same when travelling up as there is no floor to support us and we would simply fall back to Earth after each step.
The solution could be to build a very large stair case, then you could walk to space in the same way as walking to London. Otherwise you would have to jump. To jump one meter would take a large initial velocity, the world record height jumped is 1.616 meters, the velocity needed (ignoring friction and air resistance) can be found using the relatively simple formula:
Instantaneous Velocity squared = 2 times the acceleration due to gravity times the height jumped or (v2=2as)
The athlete in the video therefore needed to have an initial velocity of about 5.6 meters per second to jump height enough to succeed his World record attempt.
This Velocity is know as Delta-V, or the velocity required to complete a manoeuvre (Change in speed or direction), in the case of the athlete the velocity needed to jump high enough. Below are some more Delta-V values.
Play the Game
Objective – Jump onto the Satellite Orbiting Earth. Enter a Delta-V to Jump
Start the Game – Click anywhere on the left to start. Press the Green Flag to restart the Game
How to Control – Press the ‘Space Bar’ and input a number and press the ‘Enter’ Key to Jump. 1 is equal to 100 meters per second. Press the ‘Space Bar’ to try again
Mars and the Earth are not stationary, imagine trying to walk to London if it was constantly. Again it would not be too difficult on Earth as you could just wait for London to return to where you want it to be. However if you were trying to jump onto a moving platform then if you miss you fall back to the Earth. It is similar when trying to get to other planets, if you miss you will have to use a lot of energy to wait for the planet to come around again. So a lot of work is done working out the exact time to launch a rocket so it arrives on Mars.
Play the Game
Objective – How difficult is it to jump onto a moving object? Try to jump from the Earth to Mars.
Start the Game – Click anywhere on the left to start, then the green flag to try again.
How to Control – Jump by pressing Space… This is very difficult.
Because Earth and Mars are not stationary timing is very important. Some Maths is involved, as it takes the Earth around 360 days to orbit our Sun and Mars around 720 days (1.9 Earth years more accurately) so the two are at their closest only once in around every 500 days (or more accurately 1.6 years). You could travel to Mars at any time, but the journey would be longer and you would require more time and fuel to get there.
The Quickest we can get to Mars, unassisted, is around 260 days. To find out more there is a good paper on the NASA Website – image.gsfc.nasa.gov/poetry/venus/q2811.html.
Further Materials, Resources & Information
Below you will find more resources and external websites related to this lesson.
- Nasa.gov/edu/teach/activity/lets-go-to-mars-calculating-launch-windows/ – Mathematics Activity from NASA to show learners how to calculate launch windows.
- Projectrho.com/public_html/rocket/mission – Getting to Mars requires a lot of thought and careful calculations, Atomic Rockets have put together this list of requirements as well as some calculations to go with them.
Full STEAM Ahead – Space Exploration Education Grant
This lesson has been produced as part of the Full STEAM Ahead Project with the UK Space Agency. We are one of eight organisations across the UK to be awarded to deliver and produce exciting new education outreach activities and projects. The UK Space Agency are delighted to be able to support these projects, which represent a diverse selection of cross-curricular activities that meet it’s education objectives in encouraging children to take up STEAM subjects, raise awareness of careers in space-related areas, and raise awareness of the UK’s exploration programme.