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Questions tagged [free-return]

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8 votes
2 answers
4k views

How feasible is a manned flight to Apophis in 2029 using Artemis or Starship?

Apophis will fly by Earth around GEO altitude in 2029. May NASA consider launching an Orion spacecraft on a (sub-)orbital trajectory whose apogee is very close to Apophis so that astronauts can study ...
Johannes's user avatar
  • 229
5 votes
1 answer
443 views

Are Artemis missions launched into a free return trajectory like the Apollo program?

The Apollo program spacecrafts were put on a free return trajectory after during the TLI maneuver. Does Artemis mission also put crafts on a free return trajectory? If no, what are the redundancy ...
Ashvin's user avatar
  • 2,888
2 votes
1 answer
93 views

Using a reverse sling + compression sock to give an asteroid an initial boost - possible?

building my a related question, I have a hypothesis in question: Assuming that we can get a tug spacecraft near an asteroid worth mining, at appropriate but faster speeds can we use a slingshot with a ...
Artem Shamsutdinov's user avatar
12 votes
1 answer
2k views

Would the free return trajectories of Apollo 8 to Apollo 11 have made them reenter Earth's atmosphere?

Apollo 8 to Apollo 11 flew on a free return trajectory (later missions left the free return trajectory during a mid course correction after TLI). If those spacecraft had just stayed on that trajectory,...
TrySCE2AUX's user avatar
  • 3,255
24 votes
2 answers
4k views

How many people have witnessed Earthrise?

How many astronauts orbited or went around the moon and saw Earthrise? Am I correct in the conclusion that nine missions orbited the moon or used a free-return trajectory around the moon, Apollos 8, ...
Bob516's user avatar
  • 6,999
2 votes
0 answers
98 views

Free Return Transfer Problem

I'm trying to understand how a free-transfer return works. It makes sense to me conceptually, but putting numbers to it it is unclear. I'm not sure how to obtain information about the transfer ...
Scotch Jones's user avatar
15 votes
3 answers
2k views

Puzzler: Precisely what maximum distance from the Earth did the Apollo 13 astronauts achieve?

tl;dr: Both this answer to Which astronaut travelled farthest from Earth? this answer to How far have astronauts been in space? quote Wikipedia to state that the Apollo 13 astronauts reached 400,171 ...
uhoh's user avatar
  • 149k
4 votes
1 answer
2k views

How does Exploration Mission 1 orbit differ from Apollo-era free-return? How far from Earth (and Moon) does it go?

I'm having trouble understanding the current orbit planned for NASA's Space Launch System's Exploration Mission 1. Is it possible to explain how the planned orbit works and what the maximum distance ...
uhoh's user avatar
  • 149k
4 votes
0 answers
604 views

Are there any free return trajectories for a manned Mars flyby mission between 2018 and 2024?

I am looking for a mission profile including the delta-v for burns for an interplanetary mission to Mars. I have been unable to find any free return trajectories between 2018 and 2024, are there any?
Galen's user avatar
  • 41
3 votes
1 answer
425 views

Abort plan for Apollo 8

What was the plan if the flight controller received a no-go prior to Apollo 8's traverse of the far side of the Moon? How would they have returned to Earth without the gravity assist from the Moon?
Burgi's user avatar
  • 314
5 votes
2 answers
2k views

Could NASA send animals to Mars and back as a rehearsal before a human mission?

Animals in a "free return" trajectory around Mars and landed on Earth should give great data about the effects from microgravity and radiation. It would also test the life support systems. Wouldn't ...
LocalFluff's user avatar
4 votes
3 answers
2k views

Does NASA ever plan crewed missions without a free return trajectory?

Because the mission was launched on a free return trajectory, the crew of Apollo 13 survived. Has that abort option ever been foregone in any mission that flew or was seriously planned? (A free ...
kim holder's user avatar
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