NASA to fire a rocket at the Moon.

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  1. Sam I Am

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    In an unprecedented scientific endeavor — and what may be one of the coolest space missions ever — NASA is preparing to fly a rocket booster into the moon, triggering a six-mile-high explosion that scientists hope will confirm the presence of water.

    The four-month mission of the Lunar Crater Observation and Sensing Satellite (LCROSS), which will be directed from NASA's Ames Research Center at Moffett Field, is to discover whether water is frozen in the perpetual darkness of craters near the moon's south pole. As a potential source of oxygen for life support and hydrogen for rocket fuel, that water would be a tremendous boost to NASA's plans to restart human exploration of the moon.

    But the launch is scheduled for Thursday at Cape Canaveral, Fla. It was delayed a day to allow repairs to the space shuttle.

    Shuttle Endeavour must fly by this weekend. Otherwise the mission to deliver the final piece of the Japanese space station lab must wait until mid-July because of unfavorable sun angles that would heat up the shuttle. The moon mission — NASA's first in a decade — must be launched by Saturday as well. Otherwise it will have to wait until the end of the month for another shot.

    LCROSS is a crucial mission for Ames because it marks a return to the business of controlling space missions from Silicon Valley's NASA base, something the center hopes to build on during the next five years. Ames has planned a public

    ceremony around the launch, starting at about 11 a.m., featuring Apollo 17 astronaut Harrison Schmitt.

    And for the 20-odd scientists who helped plan the $79 million LCROSS mission and who will take command of the spacecraft after the launch, the final days before the scheduled launch have been filled with goose-bump anticipation and nagging midnight worries.

    "This has been years," Paul Tompkins, the LCROSS flight director, said of the mission preparations. "All of us have poured our lives into this."

    Intense period

    For Kimberly Ennico, the LCROSS payload scientist, those worries are focused on a critical moment less than two hours into the mission, when controllers will signal the spacecraft to turn itself on.

    NASA is launching two spacecraft to the moon on a single Atlas V rocket — LCROSS and the Lunar Reconnaissance Orbiter (LRO), a probe that will map the surface in a search for safe landing sites for astronauts. Because LRO is the primary spacecraft, LCROSS must be switched off at launch. Ennico's nine precious instruments have been cold and dark since February — she can tell you the exact number of days — and they will need to work well as the
    Video: NASA Ames Rocket to the Moon

    QUEST on KQED Public Media.
    spacecraft hurtles toward a flyby of the moon scheduled for about 3:30 a.m. next Monday, assuming the spacecraft is launched Wednesday.

    The entire first week will be an intense period for the controllers at Ames. Working overlapping 13-hour shifts, they will turn the spacecraft on after the orbiter separates, confirm LCROSS was not damaged during launch, perform a critical trajectory burn and complete the 40-minute lunar flyby, which NASA will stream on its Web site.

    "Nothing," Ennico said, "is really routine about this mission."

    LCROSS will use the moon's gravity during the flyby to catapult itself into an orbit that will take it as far as 500,000 miles away from the moon while NASA finalizes which crater to aim the spacecraft at in October.

    Visible debris

    LCROSS may be one of NASA's most participatory missions. If the spacecraft launches on schedule at 12:51 p.m. Wednesday, it would hit the moon in the early morning hours of Oct. 8. The cloud from the 350 metric tons of debris kicked up by the Centaur booster should spread six miles above the surface of the moon, hitting the sunlight and making it visible to amateur astronomers across North America. The space agency is enlisting telescopes around the country to help monitor the impact.

    The 1,664-pound spacecraft will have the best view. LCROSS will separate from the Centaur booster less than 10 hours before impact and will be less than 400 miles above the moon when the spent rocket booster collides at a speed five times faster than a bullet from a .44 Magnum. NASA plans to stream a live view from LCROSS as the Centaur, followed by the spacecraft, plows into the moon.

    Over the final four minutes of its existence, as it follows the same terminal trajectory as the Centaur, LCROSS will train its instruments and cameras on the debris cloud, searching it for the chemical signature of water.

    Previous spacecraft and ground-based instruments have detected signs of hydrogen near the moon's poles, and scientists are split over whether that is from ice that could have arrived through the impact of comets or by other means. That ice could have lingered for more than a billion years at the bottom of craters near the lunar poles that have never seen sunlight, where temperatures are more than 300 degrees below zero Fahrenheit.

    And despite all the serious scientific talk about hydrogen signatures and lunar regolith, flying a rocket booster into the moon at 5,600 mph to trigger a massive explosion is just flat-out cool.

    "We're certainly going to be making a big splash," Ennico said. "We're going to see something, but I don't know what to expect. I know on the night of the impact, I'll be running on adrenaline."

    TECHNICAL INFO - Impactor Targeting


    Figures 1 and 2 depict the trajectory that will be used to target the LCROSS Centaur upper stage and Shepherding Spacecraft into a North or South Pole crater. The 86-day (5 day earth-lunar transit plus 81 day earth orbit) Lunar Gravity-Assist, Lunar Return Orbit (LGALRO) was chosen to allow LRO time to complete its two-month commissioning phase and conduct nearly a month of science data collection of polar crater
    Figure 2
    measurements. The LGALRO orbit can be
    Figure 2
    established for any LRO launch
    opportunity and the Centaur impact can be timed to allow LRO and key ground observatories to observe the ejecta plume generated by a high-velocity and steep incident angle impact (Figure 3). Dual viewing of the Centaur impact by the LCROSS Shepherding Spacecraft and LRO can provide additional perspective and redundant data collection. The initial science scenario and Shepherding Spacecraft propellant sizing inputs assume that the Shepherding Spacecraft separates from the Centaur 9 hours before impact and that a 50 m/s braking maneuver will slow the Shepherding Spacecraft 10 minutes behind the Centaur. This allows 4 minutes of instrument observations and real-time transmission before the Shepherding Spacecraft itself impacts the same permanently shadowed crater, or if desired, one adjacent to it.

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