A Very Good Year: Looking Back at 2007

Episode Summary

Executive Summary: Planetary Radio’s 2007 year-in-review highlights a standout year for space science: new missions launched to Mars, the Moon, the asteroid belt and beyond; major results from Jupiter, Saturn, Mars, Uranus and exoplanet studies; and memorable sky events like bright comets and a lunar eclipse. The episode closes by previewing a packed 2008, with Mercury, Enceladus, Phoenix, lunar missions, and Hubble’s final servicing mission.

Main Topics: Major planetary mission launches in 2007: Bruce Bett reviewed the year’s marquee launches: Phoenix to Mars, Kaguya/SELENE and Chang’e to the Moon, and Dawn to the asteroid belt, emphasizing that these missions set up years of future science return. New Horizons’ Jupiter flyby and outer solar system science: Emily Lochtawalla discussed New Horizons’ gravity assist at Jupiter, including storm observations, Io’s volcanic activity, and the null result on undiscovered moons larger than 1 km. Mars global dust storm and rover survival: The hosts explained how a planet-wide dust storm crippled solar-powered rovers, while orbiters continued collecting climate and geological data, especially from HiRISE and spectroscopy. Saturn, Titan, and Iapetus discoveries from Cassini: Cassini’s changing orbital geometry enabled top-down views of Saturn’s rings, radar mapping of Titan’s methane/ethane lakes, and new data on the contrasting bright/dark hemispheres of Iapetus. Uranus equinox and seasonal/ring observations: Bruce highlighted Uranus’ equinox and ring-plane crossings as rare observational opportunities that revealed seasonal change and improved understanding of the planet’s rings. Exoplanet discovery progress and future prospects: The conversation noted the rapid growth of exoplanet discoveries, including five planets in one system, and looked ahead to Kepler and improved ground-based methods for finding Earth-like worlds. 2008 outlook and historical milestones: The show previewed upcoming events: Messenger’s Mercury flyby, Cassini’s Enceladus encounter, Phoenix’s Mars landing, lunar missions, Rosetta’s Steins flyby, and anniversaries including Sputnik and Explorer 1.

Key Arguments: 2007 was unusually rich in planetary exploration, with multiple new missions launched that would produce science for years to come. The New Horizons Jupiter flyby mattered not only for the gravity assist but also for valuable observations of Jupiter’s storms, Io’s volcanism, and the absence of large undiscovered Jovian moons. Mars’ dust storm showed both the vulnerability of solar-powered surface missions and the value of orbiters for global atmospheric monitoring. Cassini’s high-inclination views transformed understanding of Saturn’s rings and Titan’s polar lakes, revealing that dramatic change and long-term stability can coexist in planetary systems. Uranus at equinox offered a rare chance to study seasonal change and ring geometry, demonstrating the importance of long-baseline observations. Exoplanet science is progressing rapidly, moving from individual discoveries toward statistically rich systems and future searches for Earth analogs. The next year was framed as especially exciting because several missions were poised to return decisive first-look data or high-value flybys. NASA and international partners were entering an “International Lunar Decade,” signaling renewed global focus on the Moon before eventual human return.

Data Points: Planetary launches in 2007: 4 - Bruce cited four planetary launches: Phoenix, Kaguya/SELENE, Chang’e, and Dawn. Mars spacecraft at the time: 5 - Emily noted there were five spacecraft at Mars during the dust storm period. Sunlight received by rovers during dust storm: less than 1% - The rovers’ solar arrays were receiving under 1% of normal sunlight during the global dust storm. Jupiter flyby year: 2007 - New Horizons used Jupiter for a gravity assist and scientific observations. Undiscovered Jovian moons ruled out: larger than 1 kilometer in diameter - New Horizons’ null result constrained unknown moons at Jupiter. Exoplanets discovered: over 250 - Bruce said discoveries had surpassed 250 extrasolar planets. Planets found in 55 Cancri system: 5 - Bruce cited a system where five planets were detected in 55 Cancri. Sputnik anniversary: 50 years - 2007 marked the 50th anniversary of Sputnik, the start of the space age. Earth perihelion distance: 0.983 AU - Bruce mentioned Earth’s closest point to the Sun on January 3. Mars closest approach: 15.9 arc seconds - The trivia question asked how large Mars appeared at its December 18 opposition. Hubble mirror diameter: 2.4 meters - Bruce cited Hubble’s primary mirror size while previewing the 2008 servicing mission. Lunar Prospector anniversary: 10 years - Bruce noted the 10th anniversary of Lunar Prospector’s launch.

Pivotal Quotes: "“It’s been a big, big year for Uranus observations.”" — Bruce Bett: He was describing Uranus’ equinox and ring-plane crossings as rare, scientifically valuable events. "“We’ve got Kaguya, the International Lunar Decade, a whole flurry of international exploration.”" — Bruce Bett: He summarized the renewed global push to explore the Moon with multiple national missions. "“The rovers are solar-powered, and with all that dust between them and the sun, they were getting less than 1% of the amount of sunlight that they are typically used to.”" — Emily Lochtawala: She explained why Mars rovers had to enter survival mode during the planet-wide dust storm.

Implications: The episode frames space science as entering a high-yield phase: current missions are still returning data while new ones launch, ensuring rapid advances in planetary geology, climate, and exoplanet discovery in the years ahead.