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Planetary News: New Horizons (2006)Six Months after Launch, New Horizons Screaming its Way towards JupiterBy Amir Alexander19 July, 2006 Exactly six months after its January 19 launch, and with nine years to go before its closest approach to Pluto in June of 2015, New Horizons is "screaming its way across the solar system" said mission Principal Investigator Alan Stern of the Southwest Research Institute. Moving at 70,000 kilometers (43,500 miles) per hour, New Horizons is crossing the solar system faster than anything that has ever been launched said Stern, and it will approach Jupiter and its satellites only 13 months after launch. To get an idea of just how fast this is, consider that the Jupiter orbiter Galileo, launched in 1989, took six years to arrive at its destination. Even at this speed New Horizons would have taken years longer to reach Pluto were it not for the generous gravity assist giant Jupiter will provide along the way. The spacecraft will use this fortuitous encounter to explore the Jovian system, and the New Horizons team is working hard to prepare for the fast-approaching encounter. On June 26 Jupiter Encounter Science Team leads Jeff Moore of NASA Ames and John Spencer of the Southwest Research Institute, turned in a complete plan of Jupiter observations to the mission operations team. The plan calls for about 500 separate observations of the planet and its satellites, lasting from January to June of 2007. The observations, Stern and his colleagues believe, are going to yield a wealth of new data which will occupy scientists for years. Even more importantly for New Horizons, they will provide a full dress rehearsal for the spacecraft's flight by Pluto and its moons eight years later. Preparations for the Jupiter encounter were delayed somewhat when in early May the New Horizons team discovered that their spacecraft will be passing within 102,000 kilometers (65,000 miles) of asteroid 2002 JF56. Taking advantage of this unexpected encounter, Stern and his colleagues decided to use the opportunity to test the spacecraft's ability to "lock-on" to an object and study it while moving swiftly by. This capability would be crucial for New Horizons' observations of Jupiter, and even more so during its swift flight through the Plutonian system in 2015. But it also meant that for 6 weeks in the middle of instrument checkouts and intensive planning for the Jupiter encounter the science and operations teams had to put most everything else aside in order to plan and execute a complex and unexpected series of observations.
The results made it all worthwhile: On June 11 and 13, as it passed by the asteroid at a relative speed of 70,000 kilometers (43,500 miles) an hour, New Horizons pointed its Ralph imaging system at 2002 JF56 and took measurements of its color, size, and composition. As the spacecraft sped by, and background stars streaked and blurred, the asteroid stayed stable and in sharp focus. This, said Stern, "gives us the warm glow of direct experience," building confidence for the fly-by's of Jupiter, Pluto, and the Kuiper belt. With the asteroid encounter behind them, the New Horizons team now has a lot of catching up to do. In addition to the ongoing planning for the Jupiter encounter, they are also testing the SWAP and PEPSSI instruments and the signal from REX – their radio science experiment. They recently initiated a spin-up maneuver, switching the spacecraft from its three-axis attitude control to a 5 RPM axial spin stabilization. They also uploaded new and improved fault protection software onto the spacecraft's onboard computer, and further software upgrades are expected in August and September. All this is being done with a team that has been drastically cut back since the spacecraft's pre-launch testing days last year. At the time, Stern points out, there were almost 2500 people working on New Horizons and its related systems. The number now is around 50.
The busy year for New Horizons continued on other fronts as well. Following the recommendation of Stern and his team, the International Astronomical Union (IAU) last month approved the names "Nix" and "Hydra" for Pluto's two new moons, discovered last summer. Following the close encounter with 2002 JF56, Stern has now proposed to the IAU to name the asteroid "Johns Hopkins University Applied Physics Laboratory" in honor of APL, New Horizons' "parent" institution. The proposal is still under consideration. And also in the "naming" department, New Horizons' Student Dust Counter (SDC), the student-built experiment designed to register dust impacts on the spacecraft has been renamed "Venetia" in honor of Venetia Burney, who as an 11 year old in 1930 proposed the name "Pluto" for the newly-discovered ninth planet. It's been a busy time for the New Horizons team, and Stern frankly describes the first year as "hellacious." "Sometimes," he said, "I'm jealous of the Galileo team who had six years to plan and test for their Jupiter encounter." But he is not complaining. "Everything is working beautifully," he said; "I have no broken boxes, no sub-standard equipment, no back-up equipment online, and we're ahead on fuel." "So far it's been a dream; my only fear is that someone will wake me up and say it's still three weeks to launch." |
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