gaetanomarano Lunar Space Station

gaetanomarano · 2007-01-15 14:28:57

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I don't remember if this thread's Description ("Safe haven or for rescue of lunar crew") is mine... but, if it's mine, I don't agree with myself...

my opinion is that "safety", "redundancy", "plan-B-if-something-goes-wrong", etc. are very important (that's the reason I've written many articles and posts about it) but a LSS has many other useful purposes, and the BEST of them is: accomplish many lunar surface missions with the same crews and reusable landers

ok (I agree) ISRU and suborbital "jumps" are better, but I don't believe we will see those "things" on the moon soon (at least, NOT in the first ten years of exploration)

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gaetanomarano · 2007-01-15 14:36:16

Just took a peek again at your page and it has no means to keep it from tumbling in orbit once the landers are empty and the cev is gone.
Lunar gravity fluctuations from the uneven surface, tug of the sun when on that side and when in between the earths gravity will tug it in that direction.

the LSS doesn't need to remain every day in the same position... navigation systems are (and will be) very adaptive, so, every lunar orbit operation (dockings, refueling, etc.) can be done WHERE the space station IS (and the LSS can be reboosted only when necessary, with the Orion engine)

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dicktice · 2007-01-15 15:17:37

Not to disparage the Lunar space station, but use of L-1 shouldn't be ignored, as most useful as a location to "park" unmanned cargo carriers of sustaining and/or emergency supplies, prior to orbiting them in the plane required to land where required anywhere on the Moon's surface--not known at the time of launching from LEO.

SpaceNut · 2007-01-18 07:30:43

Here is a reference for the lunar orbit and as you will see orbital location matters for inclination and altitude.

Bizarre Lunar Orbits

The orbit of PFS-2 rapidly changed shape and distance from the Moon. In 2-1/2 weeks the satellite was swooping to within a hair-raising 6 miles (10 km) of the lunar surface at closest approach. As the orbit kept changing, PFS-2 backed off again, until it seemed to be a safe 30 miles away. But not for long: inexorably, the subsatellite's orbit carried it back toward the Moon. And on May 29, 1972—only 35 days and 425 orbits after its release—PFS-2 crashed

"The Moon is extraordinarily lumpy, gravitationally speaking," Konopliv continues. "I don't mean mountains or physical topography. I mean in mass. What appear to be flat seas of lunar lava have huge positive gravitational anomalies—that is, their mass and thus their gravitational fields are significantly stronger than the rest of the lunar crust." Known as mass concentrations or "mascons," there are five big ones on the front side of the Moon facing Earth, all in lunar maria (Latin for "seas") and visible in binoculars from Earth.

Mascons on the Moon that make its gravitational field so lumpy, as mapped by the Lunar Prospector mission, are shown in orange-red.

"There are actually a number of 'frozen orbits' where a spacecraft can stay in a low lunar orbit indefinitely. They occur at four inclinations: 27º, 50º, 76º, and 86º"—the last one being nearly over the lunar poles.

Bottom line, says Konopliv: "Carry plenty of fuel."

dicktice · 2007-01-18 13:08:41

Great iso-gravity depictions! Does this mean that the equivalent of a Global Positioning System even is feasible, when the positions of the Mascons would have to be known as well as defined by the system itself? Beacons on the surface in each location could be the answer, but at what cost?

publiusr · 2007-05-04 16:21:20

It would be nice to have.

SpaceNut · 2007-11-07 07:55:38

A New Paradigm for Lunar Orbits

"High-altitude circular orbits around the Moon are unstable," says Todd A. Ely, senior engineer for guidance, navigation, and control at NASA's Jet Propulsion Laboratory. "Put a satellite into a circular lunar orbit above an altitude of about 750 miles (1200 km) and it'll either crash into the lunar surface or it'll be flung away from the Moon altogether in a hyperbolic orbit." Depending on the specific orbit, this can happen fast: within tens of days.
Why? Earth is responsible. The gravity of massive Earth only 240,000 miles (400,000 km) from the Moon constantly tugs on lunar satellites. For a lunar orbit higher than 750 miles, Earth's pull is actually strong enough to whisk a spacecraft out of the game.
Satellites in Earth orbit don't experience this sort of interference from the Moon. The Moon has just 1/80th Earth's mass-scarcely more than 1%. Relatively speaking, the Moon is a gravitational pipsqueak. Indeed, to any satellite in Earth orbit, the gravitational pull of the Sun is 160 times stronger than any lunar influence.
Stable high-altitude lunar orbits.
Now for the good news. Ely and several colleagues have discovered a whole new class of "frozen" or stable high-altitude lunar orbits. Pictured right, they are all inclined at steep angles to the Moon's equatorial plane so they get far above the horizon at the lunar poles, and--surprise--they are all also quite elliptical.
"For better South Pole coverage, you want an ellipse with an eccentricity of about 0.6, which is pretty oval," Ely says. An eccentricity of 0 is a circle, along which a satellite travels at a constant speed around a primary body (say, the Moon) at its center. With Earth nearby, that's out of the question: "An inclined circular orbit is kind of a blank canvas where Earth can quickly work its will," Ely says.
In contrast, an eccentricity of 0.6 is an ellipse about as oval as an American football minus the pointed ends; the Moon would be at one focus of the ellipse. "The ellipse effectively 'locks in' the satellite's behavior to make it tougher for Earth to change," Ely explains. How stable are they? Ely and his colleagues calculate that certain elliptical, high-inclination, high-altitude lunar orbits may remain stable for periods of at least a century. Indeed, Ely hypothesizes the orbits could last indefinitely.
For lunar communications and navigation, Ely recommends spacing three satellites 120º apart in the same elliptical orbit at an inclination of 51º. Each satellite in turn would go screaming down past periapsis (closest approach to the lunar surface) only 450 miles (700 km) above the north lunar pole, but would each linger fully 8 hours of its 12-hour orbit at 5,000 miles (8,000 km) above the horizon over the south lunar pole. In this configuration, two of the three satellites would always be in radio line-of-sight from a South Pole moonbase.

publiusr · 2007-11-09 15:07:34

A lunar cycler. I like it.

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#51 2007-01-15 14:28:57

Re: gaetanomarano Lunar Space Station

#52 2007-01-15 14:36:16

Re: gaetanomarano Lunar Space Station

#53 2007-01-15 15:17:37

Re: gaetanomarano Lunar Space Station

#54 2007-01-18 07:30:43

Re: gaetanomarano Lunar Space Station

#55 2007-01-18 13:08:41

Re: gaetanomarano Lunar Space Station

#56 2007-05-04 16:21:20

Re: gaetanomarano Lunar Space Station

#57 2007-11-07 07:55:38

Re: gaetanomarano Lunar Space Station

#58 2007-11-09 15:07:34

Re: gaetanomarano Lunar Space Station

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