Thursday, August 22, 2013

NASA Prepares for First Virginia Coast Launch to Moon

In an attempt to answer prevailing questions about our moon, NASA is making final preparations to launch a probe at 11:27 p.m. EDT Friday, Sept. 6, from NASA's Wallops Flight Facility on Wallops Island, Va.
The small car-sized Lunar Atmosphere and Dust Environment Explorer (LADEE) is a robotic mission that will orbit the moon to 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 these characteristics of our nearest celestial neighbor will help researchers understand other bodies in the solar system, such as large asteroids, Mercury, and the moons of outer planets.


"The moon's tenuous atmosphere may be more common in the solar system than we thought," said John Grunsfeld, NASA's associate administrator for science in Washington. "Further understanding of the moon's atmosphere may also help us better understand our diverse solar system and its evolution."
The mission has many firsts, including the first flight of the Minotaur V rocket, testing of a high-data-rate laser communication system, and the first launch beyond Earth orbit from the agency's Virginia Space Coast launch facility.

LADEE also is the first spacecraft designed, developed, built, integrated and tested at NASA's Ames Research Center in Moffett Field, Calif. The probe will launch on a U.S. Air Force Minotaur V rocket, an excess ballistic missile converted into a space launch vehicle and operated by Orbital Sciences Corp. of Dulles, Va.

LADEE was built using an Ames-developed Modular Common Spacecraft Bus architecture, a general purpose spacecraft design that allows NASA to develop, assemble and test multiple modules at the same time. The LADEE bus structure is made of a lightweight carbon composite with a mass of 547.2 pounds -- 844.4 pounds when fully fueled.

"This mission will put the common bus design to the test," said Ames Director S. Pete Worden. "This same common bus can be used on future missions to explore other destinations, including voyages to orbit and land on the moon, low-Earth orbit, and near-Earth objects."

Butler Hine, LADEE project manager at Ames, said the innovative common bus concept brings NASA a step closer to multi-use designs and assembly line production and away from custom design. "The LADEE mission demonstrates how it is possible to build a first class spacecraft at a reduced cost while using a more efficient manufacturing and assembly process," Hine said.

Approximately one month after launch, LADEE will begin its 40-day commissioning phase, the first 30 days of which the spacecraft will be performing activities high above the moon's surface. These activities include testing a high-data-rate laser communication system that will enable higher rates of satellite communications similar in capability to high-speed fiber optic networks on Earth.

After commissioning, LADEE will begin a 100-day science phase to collect data using three instruments to determine the composition of the thin lunar atmosphere and remotely sense lofted dust, measure variations in the chemical composition of the atmosphere, and collect and analyze samples of any lunar dust particles in the atmosphere. Using this set of instruments, scientists hope to address a long-standing question: Was lunar dust, electrically charged by sunlight, responsible for the pre-sunrise glow above the lunar horizon detected during several Apollo missions?
After launch, Ames will serve as a base for mission operations and real-time control of the probe. NASA's Goddard Space Flight Center in Greenbelt, Md., will catalogue and distribute data to a science team located across the country.

NASA's Science Mission Directorate in Washington funds the LADEE mission. Ames manages the overall mission. Goddard manages the science instruments and technology demonstration payload, the science operations center and provides overall mission support. Wallops is responsible for launch vehicle integration, launch services and operations. NASA's Marshall Space Flight Center in Huntsville, Ala., manages LADEE within the Lunar Quest Program Office.

Monday, August 12, 2013

Swapping Motion-Sensing Units

Mission Status Report


PASADENA, Calif. -- NASA's Mars Reconnaissance Orbiter is switching from one motion-sensing device to a duplicate unit onboard.

The veteran orbiter relies on this inertial measurement unit (IMU) for information about changes in orientation. This information is important for maintaining spacecraft attitude and for pointing the orbiter's large antenna and science-observation instruments.

The spacecraft has two identical copies of this motion-sensing device, called IMU-1 and IMU-2.  Either of them can be used with either of the spacecraft's redundant main computers. Each contains three gyroscopes and three accelerometers.

"The reason we're doing this is that one of the gyroscopes on IMU-1 is approaching its end of life, so we want to swap to our redundant unit early enough that we still have some useful life preserved in the first unit," said Mars Reconnaissance Orbiter Mission Manager Reid Thomas of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The orbiter began investigating Mars in 2006. Since completing its primary science phase in 2008, it has continued to work as an extended mission.
The swap has been planned for this week, with procedures expected to take less than two days before the orbiter resumes its normal functions of science observations from orbit and communication relay for Mars rovers.

"To make sure we have a smooth transition, regaining attitude knowledge as quickly as possible, we will power off all instruments, do the IMU swap, maneuver to sun point, do the IMU swap, and then put the spacecraft into safe mode," Thomas said. "The safe-mode process re-initializes the spacecraft's knowledge of its attitude."

IMU-2 has been used previously, but IMU-1 has been used much more. After the swap, IMU-1 will remain available if needed for short periods.

The Mars Reconnaissance Orbiter has provided more data about Mars than all other earlier and current missions combined. It also relays to Earth information from both of NASA's active Mars rovers, Opportunity and Curiosity, sharing that function with the NASA Mars Odyssey orbiter.