Navigator

1. 1

   Gravitația lui Newton

   • 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

   Legile lui Kepler

   • 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

   Elemente ale orbitei

   • 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

   Viteza orbitală: ecuația vis-viva

   • 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

   Viteza de evacuare

   • 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

   De ce o orbită este o cădere

   • 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

   Ajungând pe orbită: virajul gravitațional

   • 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

   Ecuația rachetei și 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

   Transferuri de Hohmann

   • 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

    Lansarea ferestrelor

    • 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

    Inserția orbitală: captarea

    • 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 (Asistenţă gravitaţională)

    • 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

    Puncte de Lagrange

    • 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 și andocare

    • 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

    Venind acasă: reintrarea

    • 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

    Parcele pentru porci

    În curând!

17. 17

    Asteroizi și comete

    În curând!

Instrumentele și lecțiile folosesc modele simplificate doar pentru învățare, nu trebuie folosite pentru navigație, planificarea misiunii sau orice decizie operațională. Certificatele sunt gratuite și neacreditate. Citiți declarația de declinare a responsabilității privind conținutul educațional