The Planetary Science Division's missions have revolutionized our understanding of the origin and evolution of the solar system. We are living in a golden age of discovery with a large number of operating missions ranging from orbiting Mercury to heading for Pluto and beyond.
Planetary scientists are also enabling human space exploration by studying and characterizing planetary environments beyond Earth and identifying possible resources that will enable safe and effective human missions to destinations beyond low Earth orbit. Our robotic explorers are gathering data to help us understand how the planets formed, what triggered different evolutionary paths among planets, what processes are active, and how the Earth formed, evolved, and became habitable. To search for evidence of life beyond Earth, we've used this data to map zones of habitability, studied the chemistry of unfamiliar worlds, and revealed the processes that lead to conditions necessary for life. In addition, we have significantly increased our ability to detect, track, catalog, and characterize near-Earth objects that may either pose hazards to Earth or provide destinations and resources for future exploration.
"Our planetary scientists have done a splendid job and I am not the only one who thinks that. Each year, the Planetary Science Subcommittee of NASA's external Advisory Committee evaluates the progress made by NASA toward each science objective. In Fiscal Year 2014, the subcommittee found that expectations had been fully met."
As we begin a new year, I cannot help but think of all the new discoveries and accomplishments of the past year. My column this time will highlight just a few of these fantastic accomplishments. From a mission perspective these accomplishments include:
- The Mars Atmosphere and Volatile EvolutioN mission (MAVEN), launched on November 18, 2013, arrived at Mars in September 2014 and with the Indian Space Research Organization (ISRO)/Mars Orbiting Mission (MOM) mission were inserted successfully into Mars orbit
- The Curiosity rover on Mars completed its prime mission.
- The Lunar Atmosphere and Dust Environment Explorer (LADEE) launched in September 2013 and completed its mission in April 2014.
- We have also completed Critical Design Reviews for the Origins Spectral Interpretation Resource Identification Security-Regolith Explorer (OSIRIS-REx) and Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) missions.
- Mars 2020 Rover instrument selection includes 2 foreign instruments (Spain & Norway)
- All Mars missions survived Comet Siding Spring's very close encounter with Mars that occurred on October 19
- Rosetta (ESA/NASA) instruments supported Philae's lander on Comet Churyumov-Gerasimenko
Our science successes continue to gain national and international attention. Science News has been publishing its annual most important stories since 1973. . In 2014, NASA had 17.3 percent of the worldwide scientific discoveries. This represents an all-time high in the data going back to 1973, and I am proud to say, planetary science has the lions-share of it. I want to emphasize that our successes are truly due to the hard work of our planetary science community and our mission teams. The list below is just a few of the fantastic science results that have come out:
- A global albedo mosaic of MESSENGER images has been used to gather crater statistics for the northern heavily cratered terrain, which had not been previously measured or included in age analyses. With the new measurements, the oldest terrain and the large impact basins bombardment were estimated as forming as early as 4.0-4.1 billion years ago, older than previous estimates.
- MESSENGER observations revealed a detailed global study of more than 5900 lobate scarps (cliffs) and wrinkle ridges shows that the degree of contraction in Mercury is much greater than previously believed.
- The Lunar Reconnaissance Orbiter (LRO) found evidence of relatively recent lunar volcanism that is 50-200 My old compared to previous theories of the youngest being 1-1.5 By old resulting in a new thermal history.
- GRAIL helped in the knowledge and understanding of the properties of the lunar interior and revealed a fascinating network of subsurface structures.
- LADEE discovered an extensive lunar dust and gas exosphere engulfing the Moon created by the constant bombardment by micrometeorites and solar wind.
- LADEE has mapped the temporal and spatial distribution of the major components of the lunar exosphere. The data from this mission is helping unravel the sources and sinks of the various components of the lunar exosphere and will lead to a better general understanding of how exospheres are created and evolve.
- In 2014, asteroid search teams funded by NASA's Near-Earth Object Observations (NEOO) Program found another 13 asteroids larger than one km in size with orbits that come close to Earth's vicinity. Asteroid search teams also found 1072 smaller asteroids less than one km in size, but no additional near-Earth comets. This brings the total known population of NEOs to 11,341 (as of 1 September 2014). The high-precision orbit predictions computed by NASA's Jet Propulsion Laboratory (JPL) show that none of these objects is likely to strike the Earth in the next century. However, 1,495 small bodies (of which 155 are larger than one km in diameter), with 77 found this year, are in orbits that could become a hazard in the more distant future and warrant continued monitoring.
- The near-Earth asteroid 2014 HQ124 was discovered by NEOWISE on 23 April 2014. Light-curve data showed the NEA is elongated with a 0.8 magnitude change in amplitude as the object rotates. Goldstone and Arecibo telescopes obtained bistatic radar images of 2014 HQ124 on 8 June 2014, the day of its closest approach to Earth.
- Comet Siding Spring, a pristine Oort Cloud comet, imaged by Mars Reconnaissance Orbiter and Opportunity while cometary dust and gas was observed by MAVEN and Mars Express as it blanketed Mars' upper atmosphere.
- Curiosity rover discovered Mars pursued organic compounds and traces of methane.
- Opportunity identified the oldest habitable environment on Mars dating back to 3.7 billion years ago at Endeavor Crater.
- MAVEN measured how solar wind strips the Martian atmosphere over billions of years, transforming the planet from warm and wet to cold and dry
- Curiosity began its extended mission by arriving at Mt. Sharp to examine the geological strata of the mountain, revealing the ancient conditions on Mars.
- U of Bern/NASA instrument on Rosetta found that Comet 67P/C-G emits the odor of rotten eggs (hydrogen sulphide), horse stable (ammonia), pungent formaldehyde, methanol, sulphur dioxide, and carbon disulphide - an array of complex carbon and sulphur molecules!
- Instruments on the Dawn spacecraft mapped hydrogen in Vesta's surface soil at some locations. This discovery provides insight into how the Earth and other terrestrial planets may have gotten their water inventories.
- Using ESA's Herschel space observatory, scientists have made the first definitive detection of water vapor on the dwarf planet Ceres. This is the first time water vapor has been unequivocally detected on Ceres or any other object in the asteroid belt and provides proof that Ceres has an icy surface and an atmosphere. The Dawn mission will be captured in orbit around Ceres in March 2015 revealing much more about that fascinating object.
- Galileo data indicated tectonics activity on Europa, allowing the surface to communicate with its ocean.
- Observations with the NASA Infrared Telescope Facility telescope in the mid-infrared of Io's atmosphere over a Jupiter year showed that the atmosphere of Io has "seasons."
- Observations of Jupiter's moon Europa, made using the Advanced Camera for Surveys on the Hubble Space Telescope (HST), indicated the presence of plumes of water vapor erupting from the surface. The varying plume activity may be related to changing surface stresses as Europa orbits around Jupiter, similar to the observed plume activity on Saturn's moon Enceladus.
- Individual satellite footprints have been detected for all of the Galilean moons of Jupiter, but for the first time, multiple spots have been associated with Ganymede, a feature previously only associated with Io.
- Cassini data indicated that saltwater ocean may power Enceladus' geysers.
- Cassini discovered a new molecule in Titan's upper atmosphere. This is the first definitive identification of propylene gas in a planetary atmosphere outside Earth.
- New analysis of Cassini data found that Titan's smog begins with chemical reactions high in the atmosphere.
- Hubble Space Telescope observed three Kuiper Belt Objects potentially accessible by New Horizons after Pluto system encounter
Our planetary scientists have done a splendid job and I am not the only one who thinks that. Each year, the Planetary Science Subcommittee of NASA's external Advisory Committee evaluates the progress made by NASA toward each science objective. In Fiscal Year 2014, the subcommittee found that expectations had been fully met by research results that included those discussed. The NASA 2014 Strategic Review found that:
- Noteworthy progress is demonstrated by performance, cost, and schedule exceeding planned progress, scientific achievements, and clear strategies being in place for continued success.
- Appropriate and sufficient strategies are in place to achieve the Objective.
- The Planetary Science flight program has demonstrated noteworthy cost and schedule performance (e.g LADEE, MAVEN, and OSIRIS-REx).
- Risks and challenges have been identified and are being addressed appropriately. Many of the key challenges the Planetary Science Division faces in carrying out the 2014 Science Plan are common across all of the SMD science divisions, and are well articulated in chapter 3.3 of the Science Plan.
- The Division has identified and is taking advantage of a range of opportunities such as using a proven design for the next Mars rover to reduce costs and risks and partnering with other organizations, including the USGS Astrogeology Science Center in Flagstaff, Arizona on planetary cartography and mapping products.
So what's next for us? How do we follow up in 2015? We have already started the year with the closure of the first cycle of reviews after the restructuring of the Planetary Science Research & Analysis program in the ROSES 2014 solicitation, aligning research programs to the annual performance goals. We will continue to strengthen the cross-divisional collaboration between Planetary Science and Astrophysics and conduct the exoplanet research program, focusing resources on this rapidly emerging field of study.
Further, we will review the proposals for the 2014 Discovery Announcement of Opportunity and make selections. Discovery Missions are Principal Investigator-led small-class missions with focused scientific investigations. We also will continue the implementation of the New Frontiers mission, OSIRIS-REx, and the InSight mission. We will deliver NASA's contributions to fly on ESA's Jupiter Icy Moons Explorer (JUICE) mission consisting of one U.S.-led science instrument and hardware for two European instruments: the radar, ultraviolet spectrometer, and the particle environment package. The Mars 2020 Rover mission will complete Phase A and begin Phase B/Formulation. With these upcoming activities, I believe that, 2015 will be as scientifically productive as 2014 has been.