Update 2: LRO will reach the Moon on Tuesday as 09:43 UTC.
Today at 21:32:00.1 UTC (after the two earlier launch windows closed due to lightning in the area), NASA launched the Lunar Reconnaissance Orbiter (LRO) aboard the United Launch Alliance Atlas V (in configuration 401) rocket from the Space Launch Complex 41 at Merritt Island, Cape Canaveral, Florida. Along with the LRO, Atlas V also carried the Lunar Crater Observation and Sensing Satellite (LCROSS) attached to the Centaur rocket.
More launch photos are available at my Flickr Feed
The Atlas/Centaur Separation occurred at T+4 minutes and 10 seconds. At T+ 45 min the LRO Spacecraft separated from LCROSS and at about T+90 minutes LRO achieved the translunar trajectory. Within the next 24 hours the mission controllers will execute a planned mid-course correction (MCC) to LRO’s the trajectory.
After approximately four days, the lunar orbit insertion (LOI) sequence, consisting of a large LOI-1 maneuver followed by a series of smaller LO1 maneuvers, will place the spacecraft into a 30km x 216km commissioning orbit. LRO will enter its operational circular polar orbit 50 km above the lunar surface after approximately 60 days of spacecraft checkout and instruments calibrations.
LRO’s primary mission objectives are to create a comprehensive atlas of the moon’s features, find possible landing sites, locate potential resources, and test new technology. The mission will help to set the stage for further exploration of the Moon which will hopefully result in establishing a permanent human presence on the lunar surface.
After the separation from LRO, the LCROSS spacecraft will retain the Atlas V’s Centaur upper stage rocket and use it as the primary impactor for the mission. After sufficient distance from LRO is achieved, the LRO/Centaur duo will perform a maneuver to dump remaining fuel to prevent contamination of the impact site. After five days, the spacecraft and the Centaur will execute a flyby of the moon and enter into an elongated Earth orbit to position LCROSS for impact on a lunar pole.
On final approach, approximately 9 hours and 40 minutes before the first impact, LCROSS and the Centaur will separate. LCROSS will execute a 180-degrees turn around to position its instruments towards the impact. The Centaur will act as the first impactor to create a debris plume with some of the heavier material reaching a height of up to 10 km above the lunar surface. Following four minutes behind, the LCROSS will fly through the impact ejecta to collect data and relay it back to Earth before impacting the lunar surface.
The Centaur impact crater is expected to be approximately 27 m in diameter and 5m deep, while the LCROSS spacecraft impact crater is expected to be approximately 18 m in diameter and 3 m deep. The impact is expected to create a very brief visible flash lasting less than 100 milliseconds. Most of the impact ejecta will be thrown upward at a velocity of more than 250 m/s reaching altitude of up to 10-15km above lunar surface.
Currently, the impact is planned for October 9, 2009. The LRO spacecraft will be joined by the Hubble Space Telescope (HST) as well as many ground-based observatories in Hawaii, Arizona, South Africa and Japan in observing the impact. In the following days, the LCROSS team will announce the lunar pole and the primary target crater. Factoring any additional information (such as lunar libration) a final determination of the target crater will be made 30 days before impact.
The primary mission objective for the LCROSS mission is to measure the concentration of water ice (ice to dust ratio) in permanently unlit lunar regolith or soil. Other objectives include identifying the cause of the hydrogen signatures previously detected at the lunar poles and determining the composition of the regolith in one of the moon’s permanently shadowed crater.
The Atlas V rocket carries a memorial plaque for J.Bob Reiss – life-long NASA employee who spent his career working on the Atlas rocket and was instrumental in the success off missions such as the Viking, Cassini and recently launched (January 19, 2006) the New Horizons.
NASA Goddard Space Flight Center will have live mission coverage of LRO’s lunar orbit insertion (LOI) on NASA TV. Mission images, video, and animations are available for both the LRO and the LCROSS. You can follow mission twitter feeds at LRO_NASA and LCROSS_NASA