Navigator

1. 1

   Newtons tyngdekraft

   • Newton's gravity · 12 min

     One law explains falling apples, the Moon's orbit and the path of every planet. Fire Newton's cannon and find out how.

2. 2

   Keplers love

   • Kepler's laws · 14 min

     Three rules found from careful observations in the early 1600s still describe every orbit, from moons to exoplanets.

3. 3

   Orbitalelementer

   • Orbital elements · 14 min

     Six numbers pin down any orbit in space: its size, shape, tilt, orientation and where the body is on it.

4. 4

   Omløbshastighed: vis-viva ligningen

   • Orbital speed: the vis-viva equation · 12 min

     One short equation gives the speed of anything in orbit at any point, if you know how far it is and the size of its orbit.

5. 5

   Undslippehastighed

   • Escape velocity · 12 min

     How fast do you need to go to leave a world for good? And why rockets do not actually need to reach it at the surface.

6. 6

   Hvorfor en bane er et fald

   • Why an orbit is a fall · 10 min

     Astronauts float not because there is no gravity up there, but because they are falling all the time, and missing.

7. 7

   Når man når kredsløbet: tyngdekraftsvejen

   • Reaching orbit · 12 min

     Why rockets go up for only a few seconds, then spend ten minutes going sideways: the gravity turn, staging and orbital insertion.

8. 8

   Raketligningen og delta-v

   • The rocket equation and delta-v · 12 min

     Why rockets are mostly fuel, why they come in stages, and the one equation behind every mission's budget.

9. 9

   Hohmann transfers

   • Hohmann transfers: changing orbits · 12 min

     To go higher you speed up, and then you arrive slower. The two-burn manoeuvre that moves satellites from low orbit to geostationary orbit.

10. 10

    Start vinduer

    • Launch windows: the road to Mars · 12 min

      You cannot aim at Mars, only at where Mars will be in eight months. Why Mars missions leave every 26 months, all at once.

11. 11

    Indsættelse i kredsløbet: at blive fanget

    • Orbital insertion: getting captured · 12 min

      Arriving at a planet is the most dangerous minute of a mission: one burn decides whether you stay or fly past forever.

12. 12

    Gravity assists

    • Gravity assists: the free slingshot · 12 min

      How Voyager, Cassini and New Horizons stole speed from planets, and why it never breaks the conservation of energy.

13. 13

    Lagrange-punkter

    • Lagrange points: balance in the sky · 11 min

      Five places around every pair of worlds where a spacecraft can ride along for free, and why the James Webb Space Telescope lives at one of them.

14. 14

    Rendezvous og docking

    • Rendezvous: catching the space station · 11 min

      To catch something ahead of you in orbit, you drop lower and go slower-looking but faster. The counter-intuitive art of meeting in space.

15. 15

    Hjemkomst: tilbagevenden

    • Coming home: reentry · 11 min

      A small push slows a spacecraft by a hundred metres per second, and the air takes care of the other 7.8 kilometres per second, as a fireball.

16. 16

    Parceller til svinekød

    Kommer snart til dig

17. 17

    Asteroider og kometer

    Kommer snart til dig

Værktøjer og lektioner bruger forenklede modeller til undervisningsformål, men må ikke bruges til navigation, missionsplanlægning eller operationelle beslutninger. Certifikater er gratis og ikke-akkrediterede. Læs ansvarsfraskrivelsen for uddannelsesindhold