3 ms·

The Apollo missions took only 3 days to reach lunar orbit. Why is this taking longer?

hungryforcodes 4y ago
The space race is over?
api_or_ipa 4y ago
Apollo 17 launched at 12:33am on Dec 7th 1972, and entered lunar orbit at 2:47pm EST on Dec 10th, so, roughly 3.5 days. Artemis I launched at 1:47am EST on Nov 16 and entered lunar orbit on Nov 20th at 2:09pm ET so roughly 4.5 days. Remember too that Artemis I isn't meant for a landing, instead it entered a distant retrograde orbit which orbits at a considerably higher distance from the surface. Spacecraft move considerably slower at higher apogees, so I don't think there's anything suspect about Artemis I taking a bit longer to reach it's planned orbit around the Moon.
- ehsankia 4y ago
  Also, maybe the original launch date a month ago was more optimal? I'm sure it's hard trying to time the perfect launch trajectory while also juggling weather and a bunch of other variables.
adsfqwop 4y ago
I'm not an expert, but I think there's pretty much an infinite number of ways to execute space trajectories. Just looking at it visually it seems Orion is (perhaps?) taking a more roundabout (slower) route, and it's also ending up at the moon in a different orbital configuration than Apollo. Another factor, I am sure, is cost. The faster you want to get there, the more fuel you need to burn. I'm also going to guess it's not a linear equation, which means the faster you want to get there, the fuel requirements will increase in something like an exponential proportion. Therefore slower is cheaper, to a point. If you go TOO slow, your astronauts will starve, or you need to bring more food and provisions, which will cancel the cost savings on speed reduction. So somewhere in there is going to be an optimal cost/fuel/food/provision trajectory for each mission. So, in summary: different mission, different parameters for optimal execution.
- focusedone 4y ago
  This person Kerbals.
troutwine 4y ago
The Apollo missions varied in the time they took to reach lunar orbit but it's worth considering they had limited consumables to be concerned with.

The space race is over?

Apollo 17 launched at 12:33am on Dec 7th 1972, and entered lunar orbit at 2:47pm EST on Dec 10th, so, roughly 3.5 days. Artemis I launched at 1:47am EST on Nov 16 and entered lunar orbit on Nov 20th at 2:09pm ET so roughly 4.5 days. Remember too that Artemis I isn't meant for a landing, instead it entered a distant retrograde orbit which orbits at a considerably higher distance from the surface. Spacecraft move considerably slower at higher apogees, so I don't think there's anything suspect about Artemis I taking a bit longer to reach it's planned orbit around the Moon.

ehsankia 4y ago
Also, maybe the original launch date a month ago was more optimal? I'm sure it's hard trying to time the perfect launch trajectory while also juggling weather and a bunch of other variables.

adsfqwop 4y ago

I'm not an expert, but I think there's pretty much an infinite number of ways to execute space trajectories. Just looking at it visually it seems Orion is (perhaps?) taking a more roundabout (slower) route, and it's also ending up at the moon in a different orbital configuration than Apollo. Another factor, I am sure, is cost. The faster you want to get there, the more fuel you need to burn. I'm also going to guess it's not a linear equation, which means the faster you want to get there, the fuel requirements will increase in something like an exponential proportion. Therefore slower is cheaper, to a point. If you go TOO slow, your astronauts will starve, or you need to bring more food and provisions, which will cancel the cost savings on speed reduction. So somewhere in there is going to be an optimal cost/fuel/food/provision trajectory for each mission. So, in summary: different mission, different parameters for optimal execution.

focusedone 4y ago
This person Kerbals.

troutwine 4y ago

The Apollo missions varied in the time they took to reach lunar orbit but it's worth considering they had limited consumables to be concerned with.