Landing on Moon from L1?

I'm working on a book which takes place on and in a Moon base. The main character lives in a space station positioned at the L1 point a sixth of the way from the Moon to Earth. Early on she has to fly down to the base.

I'm Googling such a flight & so far haven't gotten any typical flight times. I know it's a long shot, but does anyone in this forum have any links I could follow to get an answer? Or HAVE an answer?

Thanks, all! You clarified my issues. So my solution was for her to accelerate at three Gs for "several" minutes to get a travel time of about two & a half hours, a compromise between how much fuel she wanted to use (as little as possible) for the amount of travel time (as short as possible).

I hope to have a gaggle of experts available once the book is done to go over the MS & give me better details. I expect to use the vague "several" in place of actual numbers a lot!

Smiling Ted said:

If the L1 station has ... some version of a railgun/EM launch system ... then the ferry would ... only use its own fuel to decelerate and land.

Click to expand...

Good point. Thanks! But as usual a gain in one area is matched by a loss in another - the old principle of conservation of mass and energy. Or: Everything costs. The fuel saved by the ferry has to be expended by the orbiter to keep it on station after it kicks away the lander and is thus pushed in the opposite direction. This is especially important at L1 since it is only a mildly stable Lagrange point, unlike L5 and L4, the "colonization" locations.

Still, it does have the advantage that you pointed out: it makes the lander lighter. And since the orbital instability of L1 is not that great, it could use something like a light sail rather than a fuel-guzzling rocket to maintain its position.

As usual I'll put the kitchen sink in the first draft of the book to make sure I've created a consistent setting, but may take out or mention in passing a lot of these details on rewrite to keep the story moving at the pace I want.

dpaterso said:

... I don't get why they would design the orbiter to be some kind of launch platform when ...

Click to expand...

Actually Ted covered that. His approach saves on the fuel the ferry would need to use to boost into Lunar capture orbit. It speeds up the ferry so that its orbit rises from the viewpoint of the Earth. Then it has to boost more to get into a path which intersects the point on the Moon where my heroine wants to land.

Of which there are many, incidentally. This includes paths which use very little fuel, some of which use gravity assists. These include loops around the Moon and Earth which take many days. The paths that travel most directly to the landing position use the most fuel - BUT less enviro consumables.

So there are always tradeoffs. As in all engineering solutions.

And in real life solutions. Take Cinderella. She gets a luxurious life. But she has to deal with the royal family. Some of them are boring or mean. She has to wear those heavy "beautiful" dresses which cinch in her waist to literally sickening extents. Her prince is a lousy lover: wham bam thank you ma'am. She has to have babies and babies until one is a boy and thus an heir. The royal diet is ....

Well, you could keep at this. I imagine a sequel in which Cindy plots to escape being a princess & takes up a life in another country where she is much happier being a ....

Want a laugh? I wrote the first chapter in which my MC leaves Orbiter 1 and lands at Moonbase 1 and goes inside. I fine-tuned it and felt a warm fuzzy that lasted for several days.

Then I wrote a succeeding chapter where my MC steps outside of MB1 and shivers despite the warmth of her spacesuit at the desolation of the moonscape. Then she gets to work fixing the problem she was on the Moon for. I fine-tuned it too and it was really nifty. More warm fuzzies!

A weekend later I took the two chapters to dinner with a friend who is a successful SF writer. Afterward, before I and my sweetie and his family sat down to watch a movie he read them and said something like, "Really great writing. It made me feel I was right there." He paused and I knew something less complimentary was coming.

And it did. "Throw away the first chapter and you'll have a terrific opening to a maybe terrific book."

I sulked all the way through superheroes bashing each other. The next morning I woke to the realization that he was absolutely right.

I'm seven chapters further and still going strong. The just-about-perfect launch to the book is still inspiring me.