Apollo 13 movie?

Question

answer these 2 questions for me please...
Why is funding for NASA problem after the moon walk?
What is a free-returrn trajectory?

Answer 1

1. Back in the 60's, public sentiment was all for "beating the Russians". They beat us with the first satellite, they beat us with the first man in space, we were desperately trying to beat them at something in the space race. We chose the Moon. After accomplishing that and visiting the Moon a few more times, sentiment waned as there seemed to be no more Earth shattering events to keep public attention. Congress votes for the NASA funds, and the public votes for our Congressional Representatives. Public opinion switched slightly to saving tax dollars.

2. Free Return Trajectory was one option in getting Apollo 13 back to Earth. It meant continuing to 'coast' toward the Moon, using the Moon's gravity to increase the speed of the spacecraft, going around the backside of the Moon and getting whipped back toward Earth without firing the main engine on the command module. NASA felt that the command module engine might have been damaged in the explosion of the O2 tanks. They did fire the engine on the LEM (which was still attached to the command module) several times for course corrections.

Hope that helps explain.
Have fun!

Answer 2

Funding was a problem because Apollo had cost billions of dollars, and as far as the public and congress was concerned its purpose was to land a man on the Moon before the Russians did. Apollo 11 achieved that, so many people wondered why they should keep spending billions of dollars going back to the Moon. NASA, sadly, was not very good at selling the scientific benefits of the trip, so people lost interest and funds dried up.

A free return trajectory is a failsafe. After the Saturn V launched the spacecraft into orbit it was all still attached to the third stage of the rocket. That had already been fired once to complete the orbital insertion, so they knew it worked. It fired again to launch them out of Earth's orbit on a course to the Moon. The course they followed would initially send them to the Moon in such a way that, if they could not go into orbit (say if the engine on the Apollo spacecraft failed to fire) the Moon's gravity would pull them round the back of the Moon and slingshot them back to Earth. They would therefore be guaranteed to come home even if a falure occurred.

Apollo 13 was scheduled to land at a site that could not be reached by entering orbit from a free return trajectory. It had to perform a burn midway there to get it on the right course. After the accident another burn was performed to get them back on a free return trajectory in order that they would definitely make it home even if nothing else worked for the rest of the flight.

Answer 3

The 'free' in free-returns means that it doesn't require a rocket-burn. It is 'free' in terms of the extra energy that has to be supplied - zero.

It's nice to have as a fail-safe backup. The Apollo 13 astronauts were able to get back safely because a 'free return' trajectory had been worked out that took them around the back of the moon and then towards earth. They could never have carried enough rocket fuel to get back otherwise.

Answer 4

1. it was getting really really really really expensive.....

2. using the planet (or moon's) gravity to bring the object or ship back into syncronous orbit (or in this case, back home or to the moon for a landing!)