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Aura at 20 Years

Introduction

In the 1990s and early 2000s, an international team of engineers and scientists designed an integrated observatory for atmospheric composition – a bold endeavor to provide unprecedented detail that was essential to understanding how Earth’s ozone (O3) layer and air quality respond to changes in atmospheric composition caused by human activities and natural phenomena. This work addressed a key NASA Earth science objective. Originally referred to as Earth Observing System (EOS)–CHEM (later renamed Aura,) the mission would become the third EOS Flagship mission, joining EOS-AM 1 (Terra) launched in 1999 and EOS-PM 1 (Aqua), launched in 2002. The Aura spacecraft – see Figure 1 – is similar in design to Terra and identical to Aqua. Aura and its four instruments were launched on July 15, 2004 from Vandenberg Air Force Base (now Space Force Base) in California – see Photo.

Aura 20 figure 1
Figure 1. An artist’s representation of the Aura satellite in orbit around the Earth.
Image credit: NASA
Aura nighttime launch photo
Photo.  A photo of the nighttime launch of Aura on July 15, 2004.
Image credit: NASA

In 2014 The Earth Observer published an article called  “Aura Celebrates Ten Years in Orbit,” [Nov–Dec 2014, 26:6, pp. 4–18] which details the history of Aura and the first decade of science resulting from its data. Therefore, the current article will focus on the science and applications enabled by Aura data in the last decade. It also examines Aura’s future and the legacies of the spacecraft’s instruments. Readers interested in more information on Aura and the scientific research and applications enabled by its data can visit the Aura website.

aura 20 invite graphic

Recent Science Achievements from Aura’s Instrument (in alphabetical order)

High Resolution Dynamics Limb Sounder

The capabilities of the High Resolution Dynamics Limb Sounder (HIRDLS) were compromised at launch and operations ceased in March 2008 due to an image chopper stall. Nevertheless, the HIRDLS team was able to produce a three-year dataset notable for high vertical resolution profiles of greater than 1 km (0.62 mi) for temperature and O3 in the upper troposphere to the mesosphere. Though limited, the HIRDLS dataset demonstrated the incredible potential of the instrument for atmospheric research. So much so, that scientists are now in the study phase for a new instrument, part of the proposed Stratosphere Troposphere Response using Infrared Vertically-Resolved Light Explorer (STRIVE) mission, which would have similar capabilities as HIRDLS with advancements in spectral and spatial imaging. (STRIVE is one of four missions currently undergoing one-year concept studies, as part of NASA’s Earth System Explorer Program, which was established in the 2017 Earth Science Decadal Survey. Two winning proposals will be chosen in 2025 for full development and launch in 2030 or 2032.)

Microwave Limb Sounder

The Microwave Limb Sounder (MLS) was developed to study: 1) the evolution and recovery of the stratospheric O3 layer; 2) the role of the stratosphere, notably stratospheric humidity, in climate feedback processes; and 3) the behavior of air pollutants in the upper troposphere. MLS measures vertical profiles from the upper troposphere at ~10 km altitude (6.2 mi) to the mesosphere at ~90 km (56 mi) of 16 trace gases, temperature, geopotential height, and cloud ice. Its unique measurement suite has made it the “go-to” instrument for most data-driven studies of middle atmosphere composition over the last two decades.

Data collection during the past decade has highlighted the ability of the stratosphere to exhibit surprising and/or envelope-redefining behavior, (Envelope-redefining is a term that is used to refer to an event that greatly exceeded previous observed ranges of this event.) MLS observations have been crucial for the discovery and diagnoses of these extreme events. For example, in 2019, a stratospheric sudden warming over the southern polar cap in September – rare in the Antarctic – curtailed chemical processing, leading to an anomalously weak O3 hole. As another example, prolonged hot and dry conditions in Australia during the subsequent 2019–2020 southern summer promoted the catastrophic “Australian New Year” (ANY) fires. MLS observations showed that fire-driven pyrocumulonimbus convection lofted plumes of polluted air into the stratosphere to a degree never seen during the Aura mission.

Apart from those individual plumes, smoke pervaded the southern lower stratosphere, leading to unprecedented perturbations in southern midlatitude lower stratospheric composition, with chlorine (Cl) shifting from its main reservoir species, hydrochloric acid (HCl), into the O3-destroying form, hypochlorite (ClO). Peak anomalies in chlorine species occurred in mid-2020 – months after the fires. State-of-the-art atmospheric chemistry models in which wildfire smoke has properties similar to those of sulfate (SO4) aerosols were unable to reproduce the observed chemical redistribution. New model simulations assuming that HCl dissolves more readily in smoke than in SO4 particles under typical midlatitude stratospheric conditions better match the MLS observations.

As extraordinary as these events were, their impacts on the stratosphere were spectacularly eclipsed by the impact of the January 2022 eruption of the Hunga Tonga-Hunga Ha’apai  (Hunga) volcano in the Pacific Ocean. The Hunga eruption lofted about 150 Tg of water vapor into the stratosphere – with initial injections reaching into the mesosphere. The eruption almost instantaneously increased total stratospheric water vapor by about 10%. MLS was the only sensor able to track the plume in the first weeks following the eruption. The Hunga humidity enhancement resulted in an envelope-redefining, low-temperature anomaly in the stratosphere, in turn inducing changes in stratospheric circulation. Repartitioning of southern midlatitude Cl also occurred, though to a lesser degree than following the ANY fires and in a manner broadly consistent with known chemical mechanisms. The Hunga water vapor enhancement has not substantially declined in the 2.5 years since the eruption, and studies indicate that it will likely endure for several more years.

Impacts of the Hunga humidity on polar O3 loss have also been investigated. The timing and location of the eruption were such that the plume reached high southern latitudes only after the 2022 Antarctic winter vortex had developed. Since the strong winds at the vortex edge present a transport barrier, polar stratospheric cloud (PSC) formation and O3 hole evolution were largely unaffected. When the vortex broke down at the end of the 2022 Antarctic winter, moist air flooded the southern polar region, increasing humidity in the region. Cold, moist conditions led to unusually early and vertically extensive PSC formation and Cl activation, but chemical processing ran to completion by mid-July, as typically occurs in southern winter. The cumulative chemical O3 losses ended up being unremarkable throughout the lower stratosphere. The Hunga plume was also largely excluded from the 2022–2023 Arctic vortex. The 2023–2024 Arctic O3 loss season was characterized by conditions that were dynamically disturbed and not persistently cold, and springtime O3 was near or above average. The extraordinary stratospheric hydration from Hunga has so far had minimal impact on chemical processing and O3 loss in the polar vortices in either hemisphere – see Figure 2.

Aura 20 figure 2
Figure 2. The evolution of MLS water vapor anomalies (deviations from the baseline 2005–2021 climatology) from January 2019 through December 2023 as a function of equivalent latitude at 700 K potential temperature in the middle stratosphere at ~27 km altitude (17 mi). Black contours mark the approximate edge of the polar vortex. The green triangle marks the time of the main Hunga eruption at latitude 20.54°S on January 15, 2022.
Figure credit: Updated and adapted from a 2023 paper in Geophysical Research Letters

With the end of Aura and MLS, the future for stratospheric limb sounding observations is unclear. While stratospheric O3 and aerosol will continue to be measured on a daily, near-global basis by the Ozone Mapping and Profiler Suite (OMPS) Limb Profiler (OMPS-LP) instruments on the Suomi National Polar-orbiting Partnership (Suomi NPP) and Joint Polar Satellite System (JPSS-2, -3, and -4) satellites, there are no confirmed plans for daily, near-global observations of either long-lived trace gases or halogenated species – both of which are needed to diagnose observed changes in O3. The only other sensor making such measurements, the Canadian Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE–FTS), is itself older than MLS and, as a solar occultation instrument, measures only 30 profiles-per-day, taking around a month to cover all latitudes. Similarly, no other sensor is set to provide daily, near-global measurements of stratospheric water vapor until the launch of the Canadian High-altitude Aerosols, Water vapour and Clouds (HAWC) mission in the early 2030s. Some potential new mission concepts are under consideration by both NASA and ESA, but they are subject to competition. Even if both instruments are ultimately selected, gaps in the records of many species measured by MLS are inevitable. The MLS PI is leading an effort to develop new technologies that would allow an instrument that could restart MLS measurements to be built in a far smaller mass/power footprint (e.g., 60 kg, 90 W vs. 500 kg, 500 W for Aura MLS), and technologies exist for yet-smaller MLS-like instruments that could assume the legacy of the highly impactful MLS record at low cost in future decades.

Ozone Monitoring Instrument

The Ozone Monitoring Instrument (OMI) continues the Total Ozone Mapping Spectrometer (TOMS) record for total O3 and other atmospheric parameters related to O3 chemistry and climate. It employs hyperspectral imaging in a push-broom mode to observe solar backscatter radiation in the visible and ultraviolet.

OMI is a Dutch–Finnish contribution to the Aura mission, and its remarkable stability and revolutionary two-dimensional (2D) detector (spatial in one dimension and spectral in the other) has produced a two-decade record of science- and trend-quality datasets of atmospheric column observations. OMI continues the long-term record of total column O3 measurements begun in 1979, and its observations of nitrogen dioxide (NO2), sulfur dioxide (SO2), formaldehyde (CH2O), and absorbing aerosols provided exceptional spatial resolution for study of anthropogenic and natural trends and variations of these pollutants around the world. Its radiometric and spectral stability has made it a valuable contributor for solar spectral irradiance measurements to complement dedicated solar instruments on other satellites. The many achievements made possible with OMI are documented in a review article.

OMI’s multidecade data records have revolutionized the ability to monitor air quality changes around the world, even at the sub-urban level. In particular, OMI NO2 data have been transformative. Recently, these data were used to track changes in air pollution associated with efforts to control the spread of SARS-CoV-2. OMI’s long, stable data record allowed for changes in pollution levels in 2020 – at the height of global lockdowns – to be put into historical perspective, especially within the envelope of typical year-to-year variations associated with meteorological variability. Many research studies assessed the impact of the pandemic lockdowns on air pollution, supporting novel uses of OMI data for socioeconomic-related research. For example, OMI NO2 data were shown to serve as an environmental indicator to evaluate the effectiveness of lockdown measures and as a significant predictor for the deceleration of COVID-19 spread. OMI NO2 data were also used as a proxy for the economic impact of the pandemic as NO2 is emitted during fossil fuel combustion, which is another proxy for economic activity since most global economies are driven by fossil fuels – see Animation.

Animation. OMI data show changes in average levels of NO2 from March 20 to May 20 for each year from 2015 to 2023 over the northeast U.S. Levels in 2020 were ~30%  lower relative to previous years because of efforts to slow the spread of COVID-19. OMI data indicate similar reductions in NO2 in cities across the globe in early 2020 and a gradual recovery in pollutant emissions in late 2020 into 2023. Additional images for other world cities and regions are available through the NASA Science Visualization Studio website and the Air Quality Observations from Space website.

OMI’s datasets are being continued by successor 2D detector array instruments, such as the previously mentioned Copernicus Sentinel-5P TROPOMI mission, the Republic of Korea’s Geostationary Environment Monitoring Spectrometer (GEMS), and NASA’s Tropospheric Emissions: Monitoring of Pollution (TEMPO). All of these missions have enhanced spatial resolution relative to OMI, but have benefited from the innovative retrieval algorithms pioneered by OMI’s retrieval teams.

Tropospheric Emission Spectrometer

The Tropospheric Emission Spectrometer (TES) provided vertically-resolved distributions of a number of tropospheric constituents, e.g., O3, methane (CH4), and various volatile organic compounds. The instrument was decommissioned in 2018 due to signs of aging associated with a failing Interferometer Control System motor encoder bearing. Nevertheless, TES measurements led to a number of key results regarding changes in atmospheric composition that were published over the past 10 years.

Measurements from TES, OMI, and MLS showed that transport of O3 and its precursors from East Asia offset about 43% of the decline expected in O3 over the western U.S., based on emission reductions observed there over the period 2005–2010. TES megacity measurements revealed that the frequency of high-O3 days is particularly pronounced in South Asian megacities, which typically lack ground-based pollution monitoring networks. TES water vapor and semi-heavy water measurements indicated that water transpired from Amazonian vegetation becomes a significant moisture source for the atmosphere, during the transition from dry to wet season. The increasing water vapor provides the fuel needed to start the next rainy season. Measurements of CH4 from TES and carbon monoxide (CO) from Measurements of Pollution in the Troposphere (MOPITT) on Terra showed that CH4 emissions from fires declined at twice the rate expected from changes in burned area from 2004–2014. This finding helped to balance the CH4 budget for this period, because it offset some of the large increases in fossil fuel and wetland emissions. Through direct measurement of the O3 greenhouse gas effect, TES instantaneous radiative kernels revealed the impact of hydrological controls on the O3 radiative forcing and were used to show substantial radiative bias in Intergovernmental Panel on Climate Change (IPCC) chemistry–climate models. The TES team pioneered the retrieval of a number of species, such as peroxyacetyl nitrate, carbonyl sulfide, and ethylene.

The spirit of TES lives on through the NASA TRopospheric Ozone and its Precursors from Earth System Sounding (TROPESS) project, which generates data products of O3 and other atmospheric constituents by processing data from multiple satellites through a common retrieval algorithm and ground data system. TROPESS builds upon the success of TES and is considered a bridge to allow the development of a continuous record of O3 and other trace gas species as a follow-on to TES.

Future of Aura

In April 2023, Aura’s mission operations team performed the last series of maneuvers to maintain its position in the A-Train constellation of satellites. Since then, Aura has begun drifting. As of July 2024, Aura has descended ~5 km (3 mi) in altitude from ~700 km (435 mi) and its equator crossing time has increased by ~9 min from ~1:44 PM local time. This amount of drift is small, and the Aura MLS and OMI retrieval teams are ensuring the science- and trend-quality of the datasets.

As Aura continues to drift, the amount of sunlight reaching its solar panels will slowly decrease and will no longer be able to generate sufficient power to operate the spacecraft and instruments by mid-2026. At this point, the amount of local time drift will still be relatively small – less than one hour – so the retrieval teams will be able to ensure quality for most data products until this time.

In the remaining years, Aura’s aging but remarkably stable instruments will continue to add to the unprecedented two decades of science- and trend-quality data of numerous key tropospheric and stratospheric constituents. Aura data will be key for monitoring the evolution of the Hunga volcanic plume and understanding its continued impact on the chemistry and dynamics of the stratosphere. Observations from MLS and OMI will also be used to evaluate data from new and upcoming instruments (e.g., ESA’s Atmospheric Limb Tracker for Investigation of Upcoming Stratosphere (Altius); NASA’s TEMPO, Plankton, Aerosol, Cloud, ocean Ecosystem (PACE), and Total and Spectral Solar Irradiance Sensor-2 (TSIS-2) missions, or at least used to help minimize the gaps between data collections.

Aura’s Scientific Legacy

The Aura mission has been nothing short of transformative for atmospheric research and applied sciences. The multidecade, stable datasets have furthered process-based understanding of the chemistry and dynamics of atmospheric trace gases, especially those critical for understanding the causes of trends and variations in Earth’s protective ozone layer.  

The two decades that Aura has flown have been marked by profound atmospheric changes and numerous serendipitous events, both natural and man-made. The data from Aura’s instruments have given scientists and applied scientists an unparalleled view – including at the sub-urban scale – of air pollution around the world, clearly showing the influence of rapid industrialization, environmental regulations designed to improve air quality, seasonal agricultural burning, catastrophic wildfires, and even a global pandemic, on the air we breathe. The Aura observational record spans the period that includes the decline of O3-destroying substances, and Aura data illustrate the beginnings of the recovery of the Antarctic O3 hole, a result of unparalleled international cooperation to reduce these substances.

Aura’s datasets have given a generation of scientists the most comprehensive global view to date of critical gases in Earth’s atmosphere and the chemical and dynamic processes that shape their concentrations. Many, but not all, of these datasets are being/will be continued by successor instruments that have benefited from the novel technologies incorporated into the design of Aura’s instruments as well as the innovative retrieval algorithms pioneered by Aura’s retrieval teams.

Black Separator Line

Acknowledgements
The author wishes to acknowledge the decades of hard work of the many hundreds of people who have contributed to the success of the international Aura mission. There are too many to acknowledge here and I’m sure that many names from the early days are lost to time. I would like to offer special thanks to those scientists who, back in the 1980s, first dreamed of the mission that would become Aura.

Black Separator Line

Bryan Duncan
NASA’s Goddard Space Flight Center (GSFC)

bryan.n.duncan@nasa.gov

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Last Updated
Sep 16, 2024

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      Sadly though, 2025 will mean end of science operations for Integral and Gaia. Integral, ESA's gamma-ray observatory has exotic objects in space since 2002 and Gaia concludes a decade of mapping the stars. But as some space telescopes retire, another one provides its first full data release. Launched in 2023, we expect Euclid’s data release early in the new year.
       
      Launch-wise, we’re looking forward to Copernicus Sentinel-4 and -5 (Sentinel-4 will fly on an MTG-sounder satellite and Sentinel-5 on the MetOp-SG-A1 satellite), Copernicus Sentinel-1D, Sentinel-6B and Biomass. We’ll also launch the SMILE mission, or Solar wind Magnetosphere Ionosphere Link Explorer, a joint mission with the Chinese academy of science.
       
      The most powerful version of Europe’s new heavy-lift rocket, Ariane 6, is set to fly operationally for the first time in 2025. With several European commercial launcher companies planning to conduct their first orbital launches in 2025 too, ESA is kicking off the European Launcher Challenge to support the further development of European space transportation industry.
       
      In human spaceflight, Polish ESA project astronaut Sławosz Uznański will fly to the ISS on the commercial Axiom-4 mission. Artemis II will be launched with the second European Service Module, on the first crewed mission around the Moon since 1972.
      The year that ESA looks back on a half century of European achievement will also be one of key decisions on our future. At the Ministerial Council towards the end of 2025, our Member States will convene to ensure that Europe's crucial needs, ambitions and the dreams that unite us in space become reality.
      So, in 2025, we’ll celebrate the legacy of those who came before but also help establish a foundation for the next 50 years. Join us as we look forward to a year that honours ESA’s legacy and promises new milestones in space.
      View the full article
    • By NASA
      NASA’s Glenn Research Center leaders stand with Evening With the Stars presenters. Left to right: Tim Smith, Nikki Welch, Center Director Dr. Jimmy Kenyon, Acting Deputy Director Dr. Wanda Peters, and Carlos Garcia-Galan. Credit: NASA/Jef Janis  NASA Glenn Research Center’s “An Evening With the Stars” showcased research and technology innovations that addressed this year’s theme, NASA Glenn’s Spotlight on the Stars: 10 Years and Counting. The event featured presentations from Glenn subject matter experts and a networking reception. 
      Held at Windows on the River near Cleveland’s historic waterfront on Nov. 20, the event attracted sponsors and guests from more than 50 companies, universities, and organizations eager to learn more about the center’s recent accomplishments.  
      Special guests Dennis Andersh, CEO and president of Parallax Advanced Research/Ohio Aerospace Institute; Terrence Slaybaugh, vice president of Sites and Infrastructure for JobsOhio; and Dr. Wanda Peters, NASA Glenn’s acting deputy  director, provided remarks. 
      Center Director Dr. Jimmy Kenyon took the stage to welcome visitors and share some accomplishments from an exciting year at NASA Glenn. Kenyon then introduced the presenters – NASA’s stars of the evening – and their topics. 
      “I relish this evening each year because it spotlights what is most important to our success at NASA: our people,” Kenyon said.  

      Nikki Welch is the digital manager in the Office of Communications. In this role, she helps to tell the NASA Glenn story in engaging ways for Glenn’s hundreds of thousands of followers on social media. Welch shared details about her efforts and the importance of “Connecting People to the Mission.”  
      NASA Glenn Research Center’s Nikki Welch talks about connecting people to the NASA mission through storytelling. Credit: NASA/Jef Janis  Tim Smith leads high-temperature alloy development at NASA Glenn and has led research that resulted in over a dozen research licenses and four commercial licenses. As one of the inventors of the metal alloy GRX-810, Smith shared information about Glenn’s “Super Alloy Achievements.” 
      NASA Glenn Research Center’s Tim Smith talks about NASA’s superalloy achievements. Credit: NASA/Jef Janis  Carlos Garcia-Galan is the manager of the Orion program’s European Service Module Integration Office. This module, being provided by ESA (European Space Agency), is Orion’s powerhouse. Garcia-Galan shared information on the topic “Dreaming of Going to the Moon.”  

      NASA Glenn Research Center’s Carlos Garcia-Galan talks about the spacecraft that will bring humanity back to the Moon. Credit: NASA/Jef Janis  Return to Newsletter Explore More
      1 min read Program Manager at NASA Glenn Earns AIAA Sustained Service Award 
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      Article 2 hours ago View the full article
    • By NASA
      As 1969, an historic year that saw not just one but two successful human lunar landings, drew to a close, NASA continued preparations for its planned third Moon landing mission, Apollo 13, then scheduled for launch on March 12, 1970. The Apollo 13 prime crew of Commander James A. Lovell, Command Module Pilot (CMP) Thomas K. “Ken” Mattingly, and Lunar Module Pilot (LMP) Fred W. Haise, and their backups John W. Young, John L. “Jack” Swigert, and Charles M. Duke, continued intensive training for the mission. NASA announced the selection of the Fra Mauro region of the Moon as the prime landing site for Apollo 13, favored by geologists because it forms an extensive geologic unit around Mare Imbrium, the largest lava plain on the Moon. The Apollo 13 Saturn V rolled out to its launch pad.

      Apollo 11
      The Apollo 11 astronauts meet Canadian Prime Minister Pierre Trudeau, left, on Parliament Hill in Ottawa. Image courtesy of The Canadian Press. The Apollo 11 astronauts meet with Québec premier ministre Jean Lesage in Montréal. Image courtesy of Archives de la Ville de Montreal. Apollo 11 astronauts Neil A. Armstrong, Michael Collins, and Edwin E. “Buzz” Aldrinhad returned from their Giantstep Presidential goodwill tour on Nov. 5, 1969. Due to scheduling conflicts, a visit to Canada could not be included in the same time frame as the rest of the tour, so the astronauts made a special trip to Ottawa and Montreal on Dec. 2 and 3, meeting with local officials.
      Apollo 11 astronaut Neil A. Armstrong, left, and comedian Bob Hope perform for the troops in Korat, Thailand. Armstrong, in blue flight suit, shakes hands with servicemen in Long Binh, South Vietnam. Armstrong, left, and Hope entertain the crowd in Cu Chi, South Vietnam. Armstrong joined famed comedian Bob Hope’s USO Christmas tour in December 1969. He participated in several shows at venues in South Vietnam, Thailand, and Guam, kidding around with Hope and answering questions from the assembled service members. He received standing ovations and spent much time shaking hands with the troops. The USO troupe also visited the hospital ship U.S.S. Sanctuary (AH-17) stationed in the South China Sea.

      Apollo 12
      For the first time in nearly four weeks, on Dec. 10, Apollo 12 astronauts Charles “Pete” Conrad, Richard F. Gordon, and Alan L. Bean stepped out into sunshine and breathed unfiltered air. Since their launch on Nov. 14, 1969, the trio had traveled inside their spacecraft for 10 days on their mission to the Moon and back, wore respirators during their recovery in the Pacific Ocean, stayed in the Mobile Quarantine Facility during the trip from the prime recovery ship U.S.S. Hornet back to Houston, and lived in the Lunar Receiving Laboratory (LRL) at the Manned Spacecraft Center (MSC), now NASA’s Johnson Space Center in Houston. Like the Apollo 11 crew before them, Conrad, Gordon, and Bean exhibited no symptoms of any infections with lunar microorganisms and managers declared them fit to be released from quarantine. MSC Director Robert L. Gilruth, other managers, and a crowd of well-wishers greeted Conrad, Gordon, and Bean.
      Director of the Manned Spacecraft Center, now NASA’s Johnson Space Center in Houston, Robert R. Gilruth and others greet Apollo 12 astronaut Charles “Pete” Conrad as he emerges from his postflight quarantine. Director of the Manned Spacecraft Center, now NASA’s Johnson Space Center in Houston, Robert R. Gilruth and others greet Apollo 12 astronaut Richard F. Gordon as he emerges from his postflight quarantine. Director of the Manned Spacecraft Center, now NASA’s Johnson Space Center in Houston, Robert R. Gilruth and others greet Apollo 12 astronaut Alan L. Bean as he emerges from his postflight quarantine. Addressing the crowd gathered outside the LRL, Conrad commented that “the LRL was really quite pleasant,” but all three were glad to be breathing non man-made air! While the men went home to their families for a short rest, work inside the LRL continued. Scientists began examining the first of the 75 pounds of rocks returned by the astronauts as well as the camera and other hardware they removed from Surveyor 3 for effects of 31 months exposed to the harsh lunar environment. Preliminary analysis of the TV camera that failed early during their first spacewalk on the lunar surface indicated that the failure was due to partial burnout of the Videocon tube, likely caused by the crew accidentally pointing the camera toward the Sun. Other scientists busied themselves with analyzing the data returning from the Apollo Lunar Surface Experiment Package (ALSEP) instruments Conrad and Bean deployed on the lunar surface. Mission planners examining the photographs taken from lunar orbit of the Fra Mauro area were confident that the next mission, Apollo 13, would be able to make a safe landing in that geologically interesting site, the first attempt to land in the lunar highlands.
      After taking their first steps in the sunshine, Apollo 12 astronauts Charles “Pete” Conrad, left, Alan L. Bean, and Richard F. Gordon address a large group of well-wishers outside the Lunar Receiving Laboratory. Bean, left, Gordon, and Conrad during their postflight press conference. Two days after leaving the LRL, Conrad, Gordon, and Bean held their postflight press conference in the MSC auditorium. Addressing the assembled reporters, the astronauts first introduced their wives as their “number one support team,” then provided a film and photo summary of their mission, and answered numerous questions. Among other things, the astronauts praised the spacesuits they wore during the Moon walks, indicating they worked very well and, looking ahead, saw no impediments to longer excursions on future missions. Their only concern centered around the ever-present lunar dust that clung to their suits, raising that as a potential issue for future lunar explorers.
      Director of NASA’s Kennedy Space Center in Florida Kurt H. Debus, right, presents Apollo 12 astronauts Charles “Pete” Conrad, left, Richard F. Gordon, and Alan L. Bean with photos of their launch. White House of the Apollo 12 astronauts and their wives with President Richard M. Nixon, First Lady Pat Nixon, and their daughter Tricia Nixon. Conrad, Gordon, and Bean returned to NASA’s Kennedy Space Center (KSC) in Florida on Dec. 17, where their mission began more than a month earlier and nearly ended prematurely when lightning twice struck their Saturn V rocket. KSC Director Kurt H. Debus presented each astronaut with a framed photograph of their launch in front of 8,000 workers assembled in the Vehicle Assembly Building (VAB). Of their nearly ill-fated liftoff Conrad expressed his signature confidence, “Had we to do it again, I would launch exactly under the same conditions.” Guenter Wendt and his pad closeout team had collected a piece of grounding rod from the umbilical tower, cut it into three short pieces, mounted them with the inscription “In fond memory of the electrifying launch of Apollo 12,” and presented them to the astronauts. Three days later, President Richard M. Nixon and First Lady Pat Nixon welcomed Conrad, Gordon, and Bean and their wives Jane, Barbara, and Sue, respectively, to a dinner at the White House. After dinner, they watched a film about the Apollo 12 mission as well as the recently released motion picture Marooned about three astronauts stranded in space. President Nixon requested that the astronauts pay a visit to former President Lyndon B. Johnson, who for many years championed America’s space program, and brief him on their mission, which they did in January 1970.
      The Alan Bean Day parade in Fort Worth. Apollo 12 astronaut Bean and his family deluged by shredded office paper during the parade in his honor in Fort Worth. Image credits: courtesy Fort Worth Star Telegram. On Dec. 22, the city of Fort Worth, Texas, honored native son Bean, with Conrad, Gordon, and their families joining him for the Alan Bean Day festivities. An estimated 150,000 people lined the streets of the city to welcome Bean and his crewmates, dumping a blizzard of ticker tape and shredded office paper on the astronauts and their families during the parade. City workers cleared an estimated 60 tons of paper from the streets after the event. 

      Apollo 13
      The planned Apollo 13 landing site in the Fra Mauro region, in relation to the Apollo 11 and 12 landing sites. Workers place the Spacecraft Lunar Module Adapter over the Apollo 13 Lunar Module. On Dec. 10, 1969, NASA announced the selection of the Fra Mauro region of the Moon as the prime landing site for Apollo 13, located about 110 miles east of the Apollo 12 touchdown point. Geologists favored the Fra Mauro area for exploration because it forms an extensive geologic unit around Mare Imbrium, the largest lava plain on the Moon. Unlike the Apollo 11 and 12 sites located in the flat lunar maria, Fra Mauro rests in the relatively more rugged lunar highlands. The precision landing by the Apollo 12 crew and their extensive orbital photography of the Fra Mauro region gave NASA confidence to attempt a landing at Fra Mauro. Workers in KSC’s VAB had stacked the three stages of Apollo 13’s Saturn V in June and July 1969. On Dec. 10, they topped the rocket with the Apollo 13 spacecraft, comprising the Command and Service Modules (CSM) and the Lunar Module (LM) inside the Spacecraft LM Adapter. Five days later, the Saturn V exited the VAB and made the 3.5-mile journey out to Launch Pad 39A to begin a series of tests to prepare it for the launch of the planned 10-day lunar mission. During their 33.5 hours on the Moon’s surface, Lovell and Haise planned to conduct two four-hour spacewalks to set up the ALSEP, a suite of five investigations designed to collect data about the lunar environment after the astronauts’ departure, and to conduct geologic explorations of the landing site. Mattingly planned to remain in the CSM, conducting geologic observations from lunar orbit including photographing potential future landing sites.
      Apollo 13 astronaut James A. Lovell trains on the deployment of the S-band antenna. Apollo 13 astronaut Fred W. Haise examines one of the lunar surface instruments. During the first of the two spacewalks, Apollo 13 Moon walkers Lovell and Haise planned to deploy the five ALSEP experiments, comprising:
      Charged Particle Lunar Environment Experiment (CPLEE) – flying for the first time, this experiment sought to measure the particle energies of protons and electrons reaching the lunar surface from the Sun. Lunar Atmosphere Detector (LAD) – this experiment used a Cold Cathode Ion Gauge (CCIG) to measure the pressure of the tenuous lunar atmosphere. Lunar Heat Flow Experiment (LHE) – designed to measure the steady-state heat flow from the Moon’s interior. Passive Seismic Experiment (PSE) – similar to the device left on the Moon during Apollo 12, consisted of a sensitive seismometer to record Moon quakes and other seismic activity. Lunar Dust Detector (LDD) – measured the amount of dust deposited on the lunar surface. A Central Station provided command and communications to the ALSEP experiments, while a Radioisotope Thermoelectric Generator using heat from the radioactive decay of a Plutonium-238 sample provided uninterrupted power. Additionally, the astronauts planned to deploy and retrieve the Solar Wind Collector experiment to collect particles of the solar wind, as did the Apollo 11 and 12 crews before them. Apollo 13 astronauts James A. Lovell and Fred W. Haise during the geology field trip to lava fields on the Big Island of Hawaii. Apollo 13 astronauts James A. Lovell and Fred W. Haise during the geology field trip to lava fields on the Big Island of Hawaii. Apollo 13 astronauts James A. Lovell and Fred W. Haise during the geology field trip to lava fields on the Big Island of Hawaii. Apollo 13 astronauts Lovell, Haise, Young, and Duke participated in a geology training field trip between Dec. 17 and 20 on the Big Island of Hawaii. Geologist Patrick D. Crosland of the National Park Service in Hawaii provided the astronauts with a tour of recent volcanic eruption sites in the Kilauea area, with the thought that the Fra Mauro formation might be of volcanic origin. During several traverses in the Kilauea Volcano area, NASA geologists John W. Dietrich, Uel S. Clanton, and Gary E. Lofgren and US Geological Survey geologists Gordon A. “Gordie” Swann, M.H. “Tim” Hait, and Leon T. “Lee” Silver accompanied the astronauts. The training sessions honed the astronauts’ geology skills and refined procedures for collecting rock samples and for documentary photography.

      Apollo 14
      The Apollo 14 Command and Service Modules shortly after arriving in the Manned Spacecraft Operations Building (MSOB) at NASA’s Kennedy Space Center in Florida. The Apollo 14 Lunar Module ascent stage shortly after arriving in the MSOB. S69-62154 001 Preparations for the fourth Moon landing mission, Apollo 14, continued as well. At the time tentatively planned for launch in July 1970, mission planners considered the Littrow area on the eastern edge of the Mare Serenitatis, characterized by dark material possibly of volcanic origin, as a potential landing site. Apollo 14 astronauts Commander Alan B. Shepard, CMP Stuart A. Roosa, and LMP Edgar D. Mitchell and their backups Eugene A. Cernan, Ronald E. Evans, and Joe H. Engle had already begun training for their mission. At KSC’s Manned Spacecraft Operations Building (MSOB), the Apollo 14 CSM arrived from its manufacturer North American Rockwell in Downey, California, as did the two stages of the LM from the Grumman Aerospace and Engineering Company in Bethpage, New York, in November 1969. Engineers began tests of the spacecraft shortly after their arrival. The three stages of the Apollo 14 Saturn V were scheduled to arrive at KSC in January 1970.

      To be continued …

      News from around the world in December 1969:
      December 2 – Boeing’s new 747 Jumbo Jet makes its first passenger flight, from Seattle to New York.
      December 3 – George M. Low sworn in as NASA deputy administrator.
      December 4 – A Boy Named Charlie Brown, the first feature film based on the Peanuts comic strip, is released to theaters for the first time.
      December 7 – The animated Christmas special Frosty the Snowman, makes its television debut.
      December 14 – The Jackson 5 make their first appearance on The Ed Sullivan Show.
      December 18 – The sixth James Bond film, On Her Majesty’s Secret Service, held its world premiere in London, with George Lazenby as Agent 007.
      View the full article
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