NASA’s newest Moon probe, the Lunar Atmosphere and Dust Environment Explorer (LADEE), aimed at studying the moon ultra tenuous atmosphere and dust, has deliberately plunged into the lunar surface after successfully completing its science mission.
With the probe running low on fuel during an extended bonus mission granted by NASA to collect every last drop of data, engineers at NASA’s Ames Research Center targeted LADEE to intentionally crash into the lunar far side so as to avoid any chances of destruction to the historic Apollo manned lunar landing sites.
LADEE’s final impact took place overnight between 12:30-1:22 a.m. EDT, Friday, April 18, according to NASA, which coincidentally was just hours before the SpaceX Falcon 9 blastoff from Cape Canaveral the same day.
Mission controllers allowed LADEE’s orbit to naturally decay following the conclusion of the probes extended mission in its final low-orbit science phase, when it was skimming barely two kilometers (one mile) above the pockmarked and barren lunar terrain.
During the primary mission, LADEE’s orbit around the Moon’s equator was already extremely close to the ground at altitudes ranging barely eight to 37 miles (12-60 kilometers) above the surface, and crossing over from lunar day to lunar night approximately every two hours.
The science mission duration had initially been planned to last approximately 100 days and finish with a final impact on the Moon on about March 24.
NASA granted LADEE a month-long extension since the residual rocket fuel was more than anticipated due to the expertise of the spacecrafts navigation engineers and the precision of the launch atop the Orbital Sciences Minotaur V rocket and orbital insertion.
During the extended mission lasting an additional full lunar cycle, LADEE flew at an altitude of just about one mile (2 km), thereby allowing scientists an exceptional vantage point to unravel the mysteries of the Moon’s extremely tenuous atmosphere and dust particles since the species would be present at a higher concentration.
“We’ve been keeping a healthy margin for spacecraft safety, but after the nominal mission is completed, we will relax those requirements in the interest of new science, during the extended mission phase,” Rick Elphic, LADEE project scientist at Ames, told AmericaSpace a few weeks back.
“Why even go to lower altitudes?” I asked Elphic.
Basically because the team hoped to see changes in the particle density and composition.
“The density depends on the species. For instance, argon-40 is heavier than neon-20, and has a lower scale height. That means we should see a big increase in argon compared to neon.”
“And we may see the heavier species for the first time at these really low altitudes.”
“It’s remotely possible we’ll see krypton, for instance.”
“But the real boon will be in the dust measurements.”
“LDEX (The Lunar Dust Experiment) will be measuring dust densities very close to the surface, and we will see if something new shows up. Each time we’ve dropped our orbit down to lower altitudes, we’ve been surprised by new things,” Elphic told me.
The Neutral Mass Spectrometer (NMS) will measure the identity and abundances of the exospheres constituents such as argon, neon, and krypton.
But because the Moon’s gravity field is so uneven, the probes thrusters must be frequently fired to keep it on course and prevent premature crashes.
“The moon’s gravity field is so lumpy, and the terrain is so highly variable with crater ridges and valleys that frequent maneuvers are required or the LADEE spacecraft will impact the moon’s surface,” said Butler Hine, LADEE project manager at Ames.
LADEE also survived the total lunar eclipse on April 14-15. 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, said NASA.
Watch for my follow-up story on what science LADEE achieved.
The couch-sized probe was certainly smashed to bits as it hurtled relentlessly lower and lower, finally ending in a brutal crash and vaporization from the heat generated northward of several hundred degrees.
NASA says any surviving debris may well be buried in a shallow crater formed on impact.
“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 Elphic in a post crash NASA statement.
“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.”
Scientists will try to pinpoint LADEE’s crash site in coming months by directing the telescopic NAC camera aboard the still orbiting Lunar Reconnaissance Orbiter (LRO) to conduct a photographic search of the most likely impact site locations.
LADEE was launched during a spectacular night time blastoff Sept. 6, 2013, from NASA Wallops in Virginia—visible to tens of millions—on a science mission to investigate the composition and properties of the Moon’s pristine and extremely tenuous atmosphere, or exosphere, and untangle the mysteries of its lofted lunar dust dating back to the Apollo Moon landing era.
All those objectives and more were fully accomplished during over five months investigating Earth’s nearest neighbor.
It entered lunar orbit on Oct. 6, 2013, amidst the idiotic government shutdown that negatively affected a host of U.S. science missions funded across the federal government.
“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.
The 844-pound (383-kg) robot explorer was assembled at NASA’s Ames Research Center, Moffett Field, Calif., and is a cooperative project with NASA Goddard Spaceflight Center in Maryland.
The $280 million probe is built on a revolutionary “modular common spacecraft bus,” or body, that could dramatically cut the cost of exploring space and also be utilized on space probes to explore a wide variety of inviting targets in the solar system.Missions » LADEE »