Updates MESSENGER Mission News

NASA Completes MESSENGER Mission with Expected Impact on Mercury's Surface

Mission controllers at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., confirmed today that NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft impacted the surface of Mercury, as predicted, at 3:26 p.m. EDT this afternoon (3:34 p.m. ground time).

Mission controllers were able to confirm the end of operations just a few minutes later at 3:40 p.m., when no signal was detected by the Deep Space Network (DSN) station in Goldstone, California, at the time the spacecraft would have emerged from behind the planet had MESSENGER not impacted the surface. This conclusion was independently confirmed by the DSN’s Radio Science team, who were simultaneously looking for the signal from MESSENGER from their posts in California.

MESSENGER was launched on August 3, 2004, and it began orbiting Mercury on March 18, 2011. The spacecraft completed its primary science objectives by March 2012. Because MESSENGER’S initial discoveries raised important new questions and the payload remained healthy, the mission was extended twice, allowing the spacecraft to make observations from extraordinarily low altitudes and capture images and information about the planet in unprecedented detail.

Last month — during a final short extension of the mission referred to as XM2’ — the team embarked on a hover campaign that allowed the spacecraft at its closest approach to operate within a narrow band of altitudes, 5 to 35 kilometers above the planet’s surface. On April 28, the team successfully executed the last of seven orbit-correction maneuvers (the last four of which were conducted entirely with helium pressurant after the remaining liquid hydrazine had been depleted), which kept MESSENGER aloft for the additional month, sufficiently long for the spacecraft’s instruments to collect critical information that could shed light on Mercury’s crustal magnetic anomalies and ice-filled polar craters, among other features.

With no way to increase its altitude, MESSENGER was finally unable to resist the perturbations to its orbit by the Sun’s gravitational pull, and it slammed into Mercury’s surface at around 8,750 miles per hour, creating a new crater up to 52 feet wide.

“Today we bid a fond farewell to one of the most resilient and accomplished spacecraft ever to have explored our neighboring planets,” said Sean Solomon, MESSENGER’s Principal Investigator and Director of Columbia University’s Lamont-Doherty Earth Observatory. “Our craft set a record for planetary flybys, spent more than four years in orbit about the planet closest to the Sun, and survived both punishing heat and extreme doses of radiation. Among its other achievements, MESSENGER determined Mercury’s surface composition, revealed its geological history, discovered that its internal magnetic field is offset from the planet’s center, taught us about Mercury’s unusual internal structure, followed the chemical inventory of its exosphere with season and time of day, discovered novel aspects of its extraordinarily active magnetosphere, and verified that its polar deposits are dominantly water ice. A resourceful and committed team of engineers, mission operators, scientists, and managers can be extremely proud that the MESSENGER mission has surpassed all expectations and delivered a stunningly long list of discoveries that have changed our views not only of one of Earth’s sibling planets but of the entire inner solar system.”

MESSENGER’s Final Hours

MESSENGER’s last orbit with real-time flight operations began at 11:15 a.m. EDT, with initiation of the final delivery of data and images from Mercury via the DSN 70-m antenna in Madrid, Spain. See the last image delivered here.

After a planned transition to the 34-m DSS-15 antenna at Goldstone, California, at 2:40 p.m. EDT, mission operators later confirmed the switch to a beacon-only communication signal at 3:04 p.m. The mood in the Mission Operations Center at APL was both celebratory and somber, as team members watched MESSENGER’s telemetry drop out for the last time after more than four years and 4,105 orbits at Mercury.

“We then monitored MESSENGER’s beacon signal for about 20 additional minutes,” said Mission Operations Manager Andy Calloway of APL. “It was strange to think that for those last three minutes MESSENGER had already impacted onto Mercury, but we could not confirm that fact yet because of the vast distance across space between Mercury and Earth. MESSENGER passed behind Mercury (as viewed from Earth) at 3:29 p.m., however the signal from our intrepid spacecraft started fading prior to that and dropped out for the last time at 3:25 p.m.”

At 3:38 p.m. EDT, at the time the spacecraft would have emerged from behind the planet as viewed from the Goldstone station had MESSENGER not impacted, mission operators began monitoring for a signal, but as expected they were unable to establish communications between MESSENGER and the DSN. This radio silence was the confirmation of the end of the MESSENGER mission.

Before impact, MESSENGER’s mission design team predicted that the spacecraft would pass several miles over the lava-filled Shakespeare impact basin before striking an unnamed ridge near 54.5°N latitude and 210.1°E longitude. Because the probe hit on the far side of the planet, no Earth-based telescope was able to observe the impact. Moreover, space-based telescopes are precluded from observing Mercury because of the planet’s proximity to the Sun, exposure to which would damage sensitive optics and instruments.

A future Mercury mission, such as the BepiColombo mission now in development by the European Space Agency and Japan Aerospace Exploration Agency, might be able to identify the impact crater left behind by MESSENGER. The MESSENGER team has acquired images of the entire planet, so a future mission will have MESSENGER’s observations of the region before the impact to use as a baseline for comparison with subsequent imaging data sets to help pinpoint MESSENGER’s impact site. The impact crater should be one of the youngest on Mercury and should have exposed fresh material from Mercury’s subsurface that will have been exposed to the effects of space weathering for only a limited and precisely known time, so multispectral observations of MESSENGER’s crater will provide an important constraint on rates of optical maturation of Mercury’s surface material.

“Going out with a bang as it impacts the surface of Mercury, we are celebrating MESSENGER as more than a successful mission,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington. “The Messenger mission will continue to provide scientists with a bonanza of new results as we begin the next phase of this mission--analyzing the exciting data already in the archives, and unravelling the mysteries of Mercury.”

MESSENGER’s Education and Public Outreach team included the public in the final chapter of the MESSENGER story by sponsoring a “Name that Crater,” competition, providing an opportunity for the public to name five impact craters. Thousands of submissions were received, and the winners were announced on April 29.

Although the MESSENGER flight mission has now officially ended, the science data collected by MESSENGER are archived in NASA’s Planetary Data System, where they are preserved and remain accessible for future use by the scientific community for years and even decades to come. The Science Team will continue to use these data to pose and answer questions about Mercury’s formation and evolution and the planet’s place in our Solar System through the end of the MESSENGER project in May 2016.

Additional information about MESSENGER’s top science findings is available here; the mission’s technological innovations are detailed here; and videos of team members discussing the mission are available online here.
 
It's nice that a follow-up mission to Mercury is coming right after MESSENGER, BepiColombo. It's sad that parts of the solar system are often abandoned for years or decades with no plans for any future missions. But the data that MESSENGER has taken will be studied for a long time, and we can still expect new discoveries about Mercury thanks to MESSENGER.
 
http://messenger.jhuapl.edu/news_room/details.php?id=285

MESSENGER Finds Evidence of Ancient Magnetic Field on Mercury
Mercury's magnetic field, generated by a dynamo process in its outer core, has been in place far longer than previously known, a paper by MESSENGER Participating Scientist Catherine Johnson reports.

About 4 billion years ago, Mercury's magnetic field could have been much stronger than today, as indicated by low-altitude observations made by NASA's MESSENGER spacecraft that revealed evidence of magnetization of ancient crustal rocks on Mercury.
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Former MESSENGER Mission Manager Robert Farquhar Dies at Age 83



Robert W. Farquhar, an early MESSENGER Mission Manager and a planetary trajectory pioneer who designed some of the most esoteric and complex spacecraft trajectories ever attempted, died on October 18, at the age of 83. A 50-year veteran of deep-space missions, Farquhar made pivotal contributions to the exploration of comets, asteroids, and the planets.



“Bob Farquhar was critical to the MESSENGER mission, from initial concept through launch and early operations,” offered MESSENGER Principal Investigator Sean Solomon, of Columbia University’s Lamont-Doherty Earth Observatory. “His competitive drive to achieve new firsts in space, his enthusiasm for attempting difficult tasks, and his brilliantly creative and technically thorough solutions to mission design challenges set a tone for the entire MESSENGER team. That MESSENGER was selected for flight, completed a record six planetary flybys, and became the first spacecraft to successfully orbit Mercury is in no small measure the result of Bob’s inspiration, drive, and skill at problem solving. The entire MESSENGER team will miss him.”



Farquhar was born in 1932 and raised in Chicago. He showed an interest in aviation as a child, reading about the topic and designing and building model airplanes. After serving in the Army in Japan during the Korean War, he studied aeronautical engineering at the University of Illinois and received his bachelor’s degree with honors in 1959. He went on to earn a master’s degree from the University of California, Los Angeles, in 1961. He worked briefly at Lockheed Missiles and Space Company in Sunnyvale, California, after which he completed a Ph.D. at Stanford University in 1969.



From 1969 to 1990, Farquhar worked at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and at NASA Headquarters in Washington, D.C. In 1988, as Chief of Advanced Programs with the Space Physics Division, and Program Manager for the Discovery Program with the Solar System Exploration Division, he became involved in planning spacecraft missions to Mercury and Pluto.



“I was intrigued with the possibility of developing low or moderate-cost mission and spacecraft designs that could lead to realizable flight missions with many ‘firsts,’” he wrote in his memoir, Fifty Years on the Space Frontier: Halo Orbits, Comets, Asteroids, and More.



Farquhar commissioned a study from the Jet Propulsion Laboratory (JPL) of a Mercury orbiter mission. JPL proposed a two-spacecraft Mercury Dual Orbiter (MDO) mission that would be launched on a single launch vehicle. Although the MDO mission was never selected for flight, several aspects of its mission design and operations concepts were adopted by the MESSENGER mission.



MESSENGER was selected by NASA as the seventh Discovery mission in 1999, and Farquhar — by that time at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland — was appointed Mission Manager during the mission’s development phase. In that role, he supervised the mission design and navigation tasks, and he coordinated many activities of the science, engineering, and mission operations teams. He also worked closely with Deep Space Network (DSN) representatives at JPL to ensure that MESSENGER would have adequate DSN coverage following launch.



As Mission Manager, Farquhar was heavily involved in MESSENGER's pre-launch mission design, said his long-time collaborator David Dunham. “He made a notable decision late in the spacecraft design process when he found out that the spacecraft could not deliver a delta-V in all directions. Bob insisted on correcting that deficiency by adding two small thrusters, later informally called ‘the Farquhar thrusters,’ pointing toward the Sun through holes cut in the sunshade.”



Farquhar retired from APL in 2007 and stepped down from his position as Mission Manager. In a new position he accepted at KinetX, Inc., he remained involved with the mission, serving as an advisor for MESSENGER’s navigation team.



In his memoir, he wrote that his most important contribution to the MESSENGER mission was initiating the MDO study. It “changed the mind-set of NASA and the scientific community where a majority of people believed that a Mercury orbiter mission could only be done by employing solar-electric propulsion,” he wrote. “This study set the stage for the acceptance of a low-cost ballistic mission to orbit Mercury.”



In addition to MESSENGER, Farquhar made fundamental contributions to several other space missions, including the Comet Nucleus Tour (CONTOUR). He served as the first Mission Manager for NASA’s New Horizons mission. Following a trajectory that Farquhar envisioned, that spacecraft flew past dwarf planet Pluto and its family of small moons this past July. He also conceived, and was the flight director for, the Near Earth Asteroid Rendezvous (NEAR) mission to asteroid 433 Eros — the first launch of the Discovery program and the first planetary exploration mission led by APL.



“Bob was like no other in his ability to look for and find interesting, attainable, low-cost, and unique space missions involving both spacecraft that had already completed their primary missions and spacecraft that were yet to be designed,” said APL’s Jim McAdams, MESSENGER’s Mission Design Lead, who worked alongside Farquhar for more than two decades. “Bob secured funds for mission design studies to ensure that multiple viable launch opportunities were designed and prepared for launch, a key contribution given that additional mandated spacecraft testing contributed to MESSENGER launching during its second backup launch opportunity. He also developed the skills and contacts needed to help make these missions happen, even when doing so required a miraculous competitive upset that most wouldn’t believe was possible.”



Farquhar is survived by his wife, Irina, stepdaughter, Anya, and a host of relatives.




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MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a NASA-sponsored scientific investigation of the planet Mercury and the first space mission designed to orbit the planet closest to the Sun. The MESSENGER spacecraft was launched on August 3, 2004, and was inserted into orbit about Mercury on March 18, 2011 (UTC). After orbiting the planet for more than four years, MESSENGER impacted Mercury on April 30, 2015. Sean C. Solomon, the Director of Columbia University's Lamont-Doherty Earth Observatory, leads the mission as Principal Investigator. The Johns Hopkins University Applied Physics Laboratory built and operated the MESSENGER spacecraft and manages this Discovery-class mission for NASA.


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http://messenger.jhuapl.edu/news_room/details.php?id=291

MESSENGER Mission News
March 7, 2016
MESSENGER Data May Reveal the Remains of Mercury's Oldest Crust
Mercury's surface is unusually dark, an observation that until recently had planetary scientists mystified. But in a new study published today in Nature Geoscience, a team of researchers provides evidence that the darkening agent is carbon, a finding that offers important clues to the nature of the planet's original crust.

Patrick Peplowski, a research scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, and lead author of the paper, explains that earlier measurements of the chemistry of Mercury's surface only added to this mystery because they indicated that Mercury's surface has low abundances of iron and titanium, important constituents of the most common darkening agents on the Moon and other silicate bodies.
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MESSENGER Mission News
May 17, 2017
http://messenger.jhuapl.edu
 

3D Navigation Tool among MESSENGER's Final Delivery Products to the Planetary Data System
 
NASA’s MESSENGER mission to Mercury has released an updated ACT-QuickMap tool with new 3D navigation capabilities as illustrated by this

https://messenger.quickmap.io/?proj...hOnNasgtKNyshPlFkN8iuBNsC4ZV-vMJOBPiQ0fslBggA

view of the Caloris impact basin. This update was among the new and improved products released by the agency’s Planetary Data System (PDS), an organization that archives and distributes all U.S. planetary mission data.
 
With this 16th data release, the MESSENGER mission has shared more than 10 terabytes of Mercury science data, including nearly 300,000 images, millions of spectra, and numerous map products, along with interactive tools that allow the public to explore those data, notes Susan Ensor, who for the last decade has managed the MESSENGER Science Operations Center, which oversees the preparation of these data.
 
This release, which includes the redelivery of a subset of previously delivered products as well as new products created from data acquired through the end of Mercury orbital operations on April 30, 2015, is the final one for the MESSENGER project, which ends on May 31.
 
After a 6.6-year interplanetary cruise phase, during which the spacecraft flew by Earth once, Venus twice, and Mercury three times, MESSENGER was inserted into orbit about Mercury on March 18, 2011 (UTC), becoming the first spacecraft ever to orbit the innermost planet. The primary orbital phase lasted one Earth-year and was followed by a one-year first extended mission, completed on March 17, 2013, and an additional two-year second extended mission, completed on March 28, 2015. A final one-month campaign concluded with the impact of the MESSENGER spacecraft, as planned, onto the surface of Mercury on April 30, 2015.
 
Following impact, a one-year period of data analysis and archiving concluded with MESSENGER release 15 by PDS on May 6, 2016. NASA awarded the mission a one-year extension so that the MESSENGER team could provide an additional set of data products – some new and some enhancements of previously delivered products – anticipated to be of high scientific value to the community.
 
This final data delivery includes 12 new products. Two large mosaics, offered for the first time, feature the Caloris basin and another large impact basin on Mercury.  Also provided is documentation of the low-altitude orbit analysis conducted with measurements from the Mercury Laser Altimeter (MLA), one of seven science instruments on MESSENGER.
 
“The MLA has generated improved polar digital elevation models (DEMs) using the methodology adopted for processing the low-altitude orbits generated in the final year of the MESSENGER mission,” noted MLA Instrument Scientist Greg Neumann of the NASA Goddard Space Flight Center. “The low-altitude orbital products archived in delivery 16, and the assessment of the operational navigation products, will assist in data analysis and future mission planning. The polar DEMs at latitudes north of 75°N, where MLA coverage is optimal, are the highest resolution and accuracy obtainable and will be useful for illumination studies, image registration, and thermal modeling, particularly within regions of persistent shadow.”

Eight products included in earlier releases and also included in this release (with updates to calibration or photometric corrections and/or other improvements) include improved versions of all of the global and regional image mosaics of Mercury surface.
 
“This release includes four global monochrome maps that show Mercury's geology under a range of different lighting conditions and three color maps that show the variations in materials that make up Mercury's surface,” said Mercury Dual Imaging System (MDIS) Scientist Nancy Chabot, of the Johns Hopkins University Applied Physics Laboratory. “In particular, the global eight-color map is much improved, due to improved registration between the images that are used to produce this map, resulting in a map that more clearly shows the details of Mercury's surface features.”
 
Updated MDIS global mosaics are available for download from the MESSENGER Web page.
 
During the final project extension, the MESSENGER team prepared several tutorials, including two tutorials for use in analyzing the data collected by the Fast Imaging Plasma Spectrometer (FIPS) from orbit around Mercury.  “These tutorials guide users through techniques that we use to analyze the physical properties of the measured plasma ions in detail, including their density, energy distribution, and flow direction,” explained Energetic Particle and Plasma Spectrometer Instrument Scientist Jim Raines of the University of Michigan.
 
“We also included a software model of what FIPS would observe for a given set of plasma conditions, taking into account the motion and pointing of the spacecraft automatically,” Raines added.  “We think that these tutorials will really help open access to the use of FIPS data for understanding Mercury’s space environment to a much wider audience in the space science community.”
 
All data sets in this MESSENGER release are available at

https://pds.nasa.gov/tools/subscription_service/SS-20170512.shtml. All of the MESSENGER data archived at the PDS are available at pds.nasa.gov.

 
MESSENGER Project Manager Helene Winters of APL praised the Science Operations Center team for maintaining “a record of on- or ahead-of-schedule releases to the public. This was made possible through the leadership of Susan Ensor, who was responsible for the mission’s data archiving effort, working in close coordination with her team, the MESSENGER science team, our data pipeline contractors at Applied Coherent Technology, and the PDS node representatives,” she said. “Each of the 16 data sets is thoroughly documented, so the measurements may be understood by and their use facilitated for generations of new investigators.”
 
“This 16th data release is the capstone of the MESSENGER legacy,” offered MESSENGER Principal Investigator Sean Solomon, director of Columbia University’s Lamont-Doherty Earth Observatory. “It is the hope of the many engineers and scientists who each devoted up to two decades of effort to ensure the success of the first orbital mission to Mercury that the data returned by the MESSENGER spacecraft will continue to fuel scientific discovery for decades.”
 

 
MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a NASA-sponsored scientific investigation of the planet Mercury and the first space mission designed to orbit the planet closest to the Sun. The MESSENGER spacecraft was launched on August 3, 2004, and entered orbit about Mercury on March 18, 2011 (UTC). After orbiting the planet for more than four years, MESSENGER impacted Mercury on April 30, 2015. Sean C. Solomon, the Director of Columbia University's Lamont-Doherty Earth Observatory, leads the mission as Principal Investigator. The Johns Hopkins University Applied Physics Laboratory built and operated the MESSENGER spacecraft and manages this Discovery-class mission for NASA.

 
 
 
 
Last edited:
Title Rustaveli crater on Mercury
Released 09/09/2019 9:30 am
Copyright NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Description
By studying the rocks inside impact craters like this one, ESA research fellow Joana S. Oliveira has found that the location of Mercury’s magnetic field has changed over time in surprising ways.
Just like Earth, Mercury has a liquid metallic core, the motions within generating the magnetic field. On Earth, our magnetic north and south poles drift between about 10 and 60 km per year, with our planet’s magnetic field orientation flipping more than 100 times in the course of its 4.5 billion years.
Joana used data from NASA’s MESSENGER mission, which orbited Mercury from 2011-2015, to try to better understand the magnetic history of the innermost planet. The results of the study will help inform investigations to be conducted by the joint ESA/JAXA BepiColombo mission that is on route to the planet, arriving in 2025.
Click to expand...

http://www.esa.int/spaceinimages/Images/2019/09/Rustaveli_crater_on_Mercury
 
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