NASA : NASA Spacecraft Begins Collecting Lunar Atmosphere Data

LADEE Project Manager Update: Commissioning Complete

NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) has completed the commissioning phase, and now is ready to begin the mission’s primary science phase. After the successful Orbit Lowering Maneuver (OLM-3) on Nov. 10, LADEE was in an elliptic pre-science orbit. The first six days in this orbit were dedicated to completing the science instrument commissioning, doing opportunistic science measurements in coordination with NASA’s Lunar Reconnaissance Orbiter (LRO) spacecraft, and taking measurements of the impact of the Leonids meteor shower on the lunar environment.

The team was able to conduct preliminary science activities when LADEE’s orbit brought it closest to the surface of the moon and across the sunrise terminator – the transition from night to day. After those science activities LADEE completed the fourth and final block of Lunar Laser Communication Demonstration (LLCD) operations in the commissioning phase.

Everything has been going very well during commissioning activities, even though we sometimes had to deal with unexpected events. For example, on Nov. 19, at the end of an LLCD downlink of spacecraft main memory, LADEE experienced an unexpected processor reboot and came back up in safe mode. A safe mode is a self-protective measure that the spacecraft takes when something unexpected occurs. After re-establishing communications and looking at the data leading up to the event, the engineering team determined that the reboot was triggered by a watchdog timer. These timers are designed to detect when the spacecraft processor stops responding, indicating that something unusual has happened. This could occur for a wide variety of reasons, from a radiation event to a high-priority software overloading LADEE’s onboard computer processor.

Engineers were able to determine the event data was clean leading up to the reboot, so after initial analysis the team decided to bring the spacecraft out of safe mode and continue the LLCD experiments. The spacecraft and LLCD have performed normally since that point.

Once the LLCD experiment phase was completed, the team prepared for and performed the OLM-4 maneuver at 8:53 p.m. PST Nov. 20. This main engine burn lowered the spacecraft into the final science orbit, which varies between 20 and 60 Km above the lunar surface. The varying altitude is caused by the moon’s uneven gravity field. This was the final planned use of the large main engine on the LADEE spacecraft, which has served us extremely well during the mission. The mission now is ready to perform the main science measurements over the next several months.

Butler Hine

Ames Research Center, Moffett Field, Calif.

---

Youtube Override:

Image Credit: NASA/Ames

Image Token:

 

NASA Spacecraft Begins Collecting Lunar Atmosphere Data

NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) is ready to begin collecting science data about the moon.

On Nov. 20, the spacecraft successfully entered its planned orbit around the moon's equator -- a unique position allowing the small probe to make frequent passes from lunar day to lunar night. This will provide a full scope of the changes and processes occurring within the moon's tenuous atmosphere.

LADEE now orbits the moon about every two hours at an altitude of eight to 37 miles (12-60 kilometers) above the moon's surface. For about 100 days, the spacecraft will gather detailed information about the structure and composition of the thin lunar atmosphere and determine whether dust is being lofted into the lunar sky.

"A thorough understanding of the characteristics of our lunar neighbor will help researchers understand other small bodies in the solar system, such as asteroids, Mercury, and the moons of outer planets," said Sarah Noble, LADEE program scientist at NASA Headquarters in Washington.

Scientists also will be able to study the conditions in the atmosphere during lunar sunrise and sunset, where previous crewed and robotic missions detected a mysterious glow of rays and streamers reaching high into the lunar sky.

On Nov. 20, flight controllers in the LADEE Mission Operations Center at NASA's Ames Research Center in Moffett Field, Calif., confirmed LADEE performed a crucial burn of its orbit control system to lower the spacecraft into its optimal position to enable science collection. Mission managers will continuously monitor the spacecraft's altitude and make adjustments as necessary.

"Due to the lumpiness of the moon's gravitational field, LADEE's orbit requires significant maintenance activity with maneuvers taking place as often as every three to five days, or as infrequently as once every two weeks," said Butler Hine, LADEE project manager at Ames. "LADEE will perform regular orbital maintenance maneuvers to keep the spacecraft’s altitude within a safe range above the surface that maximizes the science return."

In addition to science instruments, the spacecraft carried the Lunar Laser Communications Demonstration, NASA's first high-data-rate laser communication system. It is designed to enable satellite communication at rates similar to those of high-speed fiber optic networks on Earth. The system was tested successfully during the commissioning phase of the mission, while LADEE was still at a higher altitude.

LADEE was launched Sept. 6 on a U.S. Air Force Minotaur V, an excess ballistic missile converted into a space launch vehicle and operated by Orbital Sciences Corp. of Dulles, Va. LADEE is the first spacecraft designed, developed, built, integrated and tested at Ames. It also was the first probe launched beyond Earth orbit from NASA's Wallops Flight Facility on the Virginia coast.

NASA's Science Mission Directorate in Washington funds the LADEE mission. Ames manages the overall mission and serves as a base for mission operations and real-time control of the probe. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the science instruments and technology demonstration payload, the science operations center and overall mission support. NASA's Marshall Space Flight Center in Huntsville, Ala., manages LADEE within the Lunar Quest Program Office.

For more information about the LADEE mission, visit:

http://www.nasa.gov/ladee

 NASA
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com

Inscríbete en el Foro del blog y participa : A Vuelo De Un Quinde - El Foro!