Concept art showing LADEE over the lunar
surface
Image Credit:
NASA
Ground controllers at NASA's Ames Research Center in Moffett Field, Calif.,
have confirmed that NASA's Lunar Atmosphere and Dust Environment Explorer
(LADEE) spacecraft impacted the surface of the moon, as planned, between 9:30
and 10:22 p.m. PDT Thursday, April 17.
LADEE lacked fuel to maintain a long-term lunar orbit or continue science
operations and was intentionally sent into the lunar surface. The spacecraft's
orbit naturally decayed following the mission's final low-altitude science
phase.
During impact, engineers believe the LADEE spacecraft, the size of a vending
machine, broke apart, with most of the spacecraft’s material heating up several
hundred degrees – or even vaporizing – at the surface. Any material that
remained is likely buried in shallow craters.
"At the time of impact, LADEE was traveling at a speed of 3,600 miles per
hour – about three times the speed of a high-powered rifle bullet," said Rick
Elphic, LADEE project scientist at Ames. "There’s nothing gentle about impact at
these speeds – it’s just a question of whether LADEE made a localized craterlet
on a hillside or scattered debris across a flat area. It will be interesting to
see what kind of feature LADEE has created."
In early April, the spacecraft was commanded to carry out maneuvers that
would lower its closest approach to the lunar surface. The new orbit brought
LADEE to altitudes below one mile (two kilometers) above the lunar surface. This
is lower than most commercial airliners fly above Earth, enabling scientists to
gather unprecedented science measurements.
On April 11, LADEE performed a final maneuver to ensure a trajectory that
caused the spacecraft to impact the far side of the moon, which is not in view
of Earth or near any previous lunar mission landings. LADEE also survived the
total lunar eclipse on April 14 to 15. This demonstrated the spacecraft's
ability to endure low temperatures and a drain on batteries as it, and the moon,
passed through Earth's deep shadow.
In the coming months, mission controllers will determine the exact time and
location of LADEE's impact and work with the agency’s Lunar Reconnaissance
Orbiter (LRO) team to possibly capture an image of the impact site. Launched in
June 2009, LRO provides data and detailed images of the lunar surface.
"It's bittersweet knowing we have received the final transmission from the
LADEE spacecraft after spending years building it in-house at Ames, and then
being in constant contact as it circled the moon for the last several months,"
said Butler Hine, LADEE project manager at Ames.
Launched in September 2013 from NASA's Wallops Flight Facility in Virginia,
LADEE began orbiting the moon Oct. 6 and gathering science data Nov. 10. The
spacecraft entered its science orbit around the moon's equator on Nov. 20, and
in March 2014, LADEE extended its mission operations following a highly
successful 100-day primary science phase.
LADEE also hosted NASA’s first dedicated system for two-way communication
using laser instead of radio waves. The Lunar Laser Communication Demonstration
(LLCD) made history using a pulsed laser beam to transmit data over the 239,000
miles from the moon to the Earth at a record-breaking download rate of 622
megabits-per-second (Mbps). In addition, an error-free data upload rate of 20
Mbps was transmitted from the primary ground station in New Mexico to the Laser
Communications Space Terminal aboard LADEE.
LADEE gathered detailed information about the structure and composition of
the thin lunar atmosphere. In addition, scientists hope to use the data to
address a long-standing question: Was lunar dust, electrically charged by
sunlight, responsible for the pre-sunrise glow seen above the lunar horizon
during several Apollo missions?
"LADEE was a mission of firsts, achieving yet another first by successfully
flying more than 100 orbits at extremely low altitudes," said Joan Salute, LADEE
program executive, at NASA Headquarters in Washington. "Although a risky
decision, we're already seeing evidence that the risk was worth taking.”
A thorough understanding of the 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.
NASA also included the public in the final chapter of the LADEE story. A
“Take the Plunge” contest provided an opportunity for the public to guess the
date and time of the spacecraft’s impact via the internet. Thousands submitted
predictions. NASA will provide winners a digital congratulatory certificate.
NASA's Science Mission Directorate in Washington funds the LADEE mission.
Ames was responsible for spacecraft design, development, testing and mission
operations, in addition to managing the overall mission. NASA's Goddard Space
Flight Center in Greenbelt, Md., managed the science instruments, technology
demonstration payload and science operations center, and provided mission
support. Goddard also manages the LRO mission. Wallops was responsible for
launch vehicle integration, launch services and operations. NASA's Marshall
Space Flight Center in Huntsville, Ala., managed LADEE within the Lunar Quest
Program Office.
For more information about the LADEE mission, visit:
For more information about LLCD, visit:
NASA
Guillermo Gonzalo Sánchez Achutegui
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