Is it possible to orbit the moon

You could imagine a massive moon distantly orbiting Neptune, and around that moon, there could be a moon of its own. NASA is considering a mission to capture an asteroid and put it into orbit around the Moon. This would be safer than having it orbit the Earth, but still keep it close enough to extract resources.

But without any kind of orbital boost, those tidal forces will eventually crash it onto the Moon. What would you suggest? Podcast audio : Download Duration: — 3. Podcast video : Download While the near side of the moon is smoothed by maria — large dark plains created by solidified lava flows — and light lunar highlands, the far side is heavily cratered.

Although you can't see the back side of the moon from Earth, NASA and other space agencies have glimpsed it with satellites. The rotational period of the moon wasn't always equal to its orbit around the planet. Just like the gravity of the moon affects ocean tides on the Earth, gravity from Earth affects the moon. But because the moon lacks an ocean, Earth pulls on its crust, creating a tidal bulge at the line that points toward Earth.

Infographic : Inside Earth's moon. Gravity from Earth pulls on the closest tidal bulge, trying to keep it aligned.

This creates tidal friction that slows the moon's rotation. Over time, the rotation was slowed enough that the moon's orbit and rotation matched , and the same face became tidally locked, forever pointed toward Earth. The moon is not the only satellite to suffer friction with its parent planet.

Many other large moons in the solar system are tidally locked with their partner. Of the larger moons, only Saturn's moon Hyperion , which tumbles chaotically and interacts with other moons, is not tidally synchronized. The Moon itself plunged the subsatellite to its death. That's the conclusion of Alex S. He and several colleagues have been analyzing the orbits of various Moon-orbiting satellites since PFS-2, notably the —99 mission of Lunar Prospector.

So why did PFS-2, which was inserted into an elliptical orbit that originally carried it from 52 miles 97 km to 66 miles km , end up as a kamikaze blast of broken aluminum struts and solar panels? 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.

The mascons' gravitational anomaly is so great—half a percent—that it actually would be measurable to astronauts on the lunar surface.

Moreover, an astronaut in full spacesuit and life-support gear whose lunar weight was exactly 50 pounds at the edge of the mascon would weigh 50 pounds and 4 ounces when standing in the mascon's center. Above: Mascons on the Moon that make its gravitational field so lumpy, as mapped by the Lunar Prospector mission, are shown in orange-red. The five largest all correspond to the largest lava-filled craters or lunar "seas" visible in binoculars on the near side of the Moon: Mare Imbrium, Mare Serenitatus, Mare Crisium, Mare Humorum and Mare Nectaris.

Image reference: Konopliv et al , Icarus , 1—18 As a satellite passes 50 or 60 miles overhead, the mascons pull it forward, back, left, right, or down, the exact direction and magnitude of the tugging depends on the satellite's trajectory. Thus, if rate of spin, mass, or lever arm changes, then the remaining quantities must change in some compensating way to keep angular momentum constant.

Example: if a spinning skater brings her arms in close to her body shortens the lever arm distance , she starts spinning faster.

The constancy of the angular momentum vector is also why gyroscopes are used to stabilize the orientation of spacecraft such as the Hubble Space Telescope in space. What does all this have to do with lunar orbits? Every orbit has angular momentum. Satellites can be fairly massive kilograms , and the lever arms can be hundreds or thousands of kilometers long.

Now, if a lunar orbit is circular with the Moon at the center, the satellite travels with constant velocity—a situation that makes it vulnerable to Earth's gravitational pull. Such a change in tilt is resisted by the angular momentum vector, just as the spinning bicycle wheel resisted your attempts to change its tilt. Below a critical inclination of Such low-inclination elliptical orbits circulate around the Moon. Above that critical inclination of Nov 30, Recommended Articles.

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