- #1
alex123go
- 2
- 0
Hi everyone,
For one of my project in school, i need to calculate the travel time to the moon. To do that, I thought to use Kepler's third law which is :
(2(pi) / P )2 * a3 = GM
where :
P : period of travel
a : major semiaxes (not sure in english, but it is the half the longest radius of the ellipse) : in this case half of the earth-moon distance : 380 400km/2= 190 200km
G : gravitational constant : 6.67E-11
M : Earth's mass : 5,972E24 kg
Whit these values, my period is equal to 9 days and 13 hours, so the travel time to the moon is the half of that and is 4 days and 18 hours.
But in the apollo program, it takes about 3 days to go to the moon. Can someone help me to figure out why does I have almost 2 days of difference.
Is it because I didn't took notice of the moon gravity, because the spacecraft wasn't doing an ellipse like this or for another reason?
Thank you for your help
For one of my project in school, i need to calculate the travel time to the moon. To do that, I thought to use Kepler's third law which is :
(2(pi) / P )2 * a3 = GM
where :
P : period of travel
a : major semiaxes (not sure in english, but it is the half the longest radius of the ellipse) : in this case half of the earth-moon distance : 380 400km/2= 190 200km
G : gravitational constant : 6.67E-11
M : Earth's mass : 5,972E24 kg
Whit these values, my period is equal to 9 days and 13 hours, so the travel time to the moon is the half of that and is 4 days and 18 hours.
But in the apollo program, it takes about 3 days to go to the moon. Can someone help me to figure out why does I have almost 2 days of difference.
Is it because I didn't took notice of the moon gravity, because the spacecraft wasn't doing an ellipse like this or for another reason?
Thank you for your help