Star Talk: Zeroing in on the moon

Two new missions to the moon are currently set to lift off in mid-June with the ultimate goal of ret

Two new missions to the moon are currently set to lift off in mid-June with the ultimate goal of returning humans to the lunar surface. The first, the Lunar Reconnaissance Orbiter, will map the moon’s surface for minerals and future landing sites; the other, known by the acronym LCROSS, will crash into the moon to determine if frozen water exists there.

NASA’s “Vision for Space Exploration,” the agency’s new strategy for returning to the moon and beyond, starts next month when the Lunar Reconnaissance Orbiter and the LCROSS impactor are paired on a single Atlas-class rocket for launch. These will be America’s first missions to the moon in more than a decade.

The last American spacecrafts that went to the moon were called Clementine and the Lunar Prospector. These vehicles found tantalizing evidence of frozen water at the moon’s north and south poles. It is suspected that the floors of certain craters at these locations are permanently shaded from the sun. Here, the sun’s illumination angle is so low that sunlight never reaches the bottoms of craters.

That’s very good news for finding water on the moon. Usually in the lunar environment, water would be so unstable that when warmed by sunlight, it would quickly disappear into space. However, since the moon does not have an atmosphere, a region of the moon that never receives sunlight would be so cold — more than 300 degrees below zero — that water would remain in an extreme frozen state.

Orbiter and impactor

The Lunar Reconnaissance Orbiter is scheduled for a one-year nominal mission time. As it circles the moon during its first year, the orbiter will perform a detailed, precision mapping of the lunar surface to locate potential resources, such as water and important minerals. It will also seek out safe landing sites and study the moon’s radiation environment, all for the purpose of humans returning to the moon.

This spacecraft will be put into a shallow lunar orbit, flying at an altitude of only 30 miles to obtain high-definition images of the moon’s surface. These views are expected to be so clear that pictures will show the equipment abandoned more than 35 years ago by the Apollo astronauts who walked on the moon. Such equipment includes the lunar landing and liftoff platform and, at some sites, a lunar rover.

Riding on the same rocket with the Lunar Reconnaissance Orbiter is the Lunar Crater Observation and Sensing Satellite (LCROSS). This satellite is the high-profile part of the mission that will test for water in the lunar soil — with a bang.

About four months after liftoff, LCROSS and the Atlas rocket’s upper stage will separate. This part of the rocket will then become a projectile aimed to collide with one of the moon’s shadowed craters. It will slam into the crater’s base at more than 5,600 miles per hour — more than twice the speed of a bullet and with more energy than a ton of TNT.

The resulting blast will make a hole in the crater floor about one-third the size of a football field and release more than 1,000 tons of material. The subsequent debris plume could stretch as much as 10 miles or more above the lunar surface and should be bright enough for experienced moon observers to see with large amateur telescopes.

Four minutes after impact, the LCROSS spacecraft will fly through the ejected plume and use its instruments to confirm the presence or absence of water in the material. Back on Earth, professional astronomers will turn their telescopes atop Mauna Kea in Hawaii to the plume and decipher its light for clues to its composition.

Finding water on the moon is important. Transporting material into space is expensive, roughly $10,000 per pound. Locating resources on the moon would expedite a lunar base. Future astronauts could not only use moon water for drinking but, when it is separated at the molecular level, it would provide breathable oxygen as well as hydrogen for propellant. A successful lunar base would eventually serve as a springboard to the rest of the solar system.

Endeavor in June

After the very successful Hubble repair mission by the crew of the space shuttle Atlantis, the Endeavor shuttle, which stood ready in case a rescue mission had to be mounted for Atlantis, is now in the final stages of preparation for its own assignment. Targeted to launch on June 13, space shuttle mission STS-127 will be the 32nd construction flight to the International Space Station and the 23rd flight for Endeavor.

Just as with the Hubble mission, there will be five spacewalks to deliver, install and service system components, this time for the space station. In particular, this 16-day mission will be the third of three shuttle flights to complete the assembly of an external science platform on the station.

Built by the Japanese Aerospace Exploration Agency, the Kibo (“hope”) laboratory will be finished by attaching the exposed section of the lab to the space station. In this way, science experiments can be placed on this external platform and be exposed directly to the outer space environment.

June sky

Saturn is the only bright planet in the evening sky this June. It first becomes visible in the southwest at dusk and is against the stars of Leo, between the lion’s two brightest stars, Regulus and Denebola.

If you have a telescope, be sure to use it soon to look at Saturn. The angle of the planet’s rings toward Earth is decreasing and the rings will face edgewise toward us in early September. Unfortunately, Saturn will then appear too close to the sun to be seen.

Saturn is currently setting in the west about 2 a.m. but about an hour before that, Jupiter comes up in the east-southeast. At present, the planet Neptune appears very close to the upper right of Jupiter. Too faint to be found by the unaided eye, Neptune can be seen together with Jupiter when using a wide-field eyepiece in a telescope.

Mars and Venus also appear close to each other in the morning sky. Both rise just north of east after 3 a.m., with Venus more than 100 times brighter than Mars.

Look for the moon tonight to the lower left of Saturn; then on June 13 and 14, you’ll find the moon near Jupiter. During the third week of June, the crescent moon will be in the east in the morning sky; find it on June 19 above Mars and Venus.

Richard Monda is an astronomer living in the Capital Region.

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