Report from the 2011 New Horizons Science Team Meeting
Posted by Ted Stryk
2011/01/24 01:01 CST
You've seen Ted Stryk's image processing work frequently on this blog. As with last year, he was invited to attend the annual New Horizons science team meeting, and sent in this report. --ESL
The annual New Horizons Science Team Meeting was held last week at NASA's Ames Research Center. The first bit of news is that project manager Glen Fountain, who originally planned to retire after launch, has decided to stay with the project through the Pluto flyby in 2015.
This year will be a quiet year on the spacecraft. In order to save fuel and money, New Horizons is kept in hibernation most of the time. However, it wakes up once a year to test the instruments and to conduct cruise science. Every other year, the spacecraft is put into three-axis-stabilized mode, allowing the instruments that have to be pointed (such as the cameras) to conduct science. During the alternate years, including 2011, the spacecraft is left in spin-stabilized mode. Fields and particles instruments take data, but the other instruments are merely checked out to make sure they are working.
There is still one big science opportunity that is not dependent on three-axis stabilization. On four occasions this year, the spacecraft will be occulted by the Moon [that is, it will appear to pass behind the Moon as seen from Earth]. Ivan Linscott, of the Radio Science Experiment, described how at least one of these occultations will be used to study electrons near the lunar surface. To conduct this experiment, New Horizons will record a signal that is transmitted to it from the ground as it passes behind the Moon, and then return the recorded signal to earth. The only time this experiment has been conducted before (a distant spacecraft recording the signal from Earth) was in 1967, when Pioneer 7 passed behind the Moon. In his master's thesis, Jose Carlos Pomalaza-Diaz demonstrated evidence in this dataset for an electron deficiency near the lunar surface. This will be the first opportunity to check these findings.
Over the past few years, LORRI, the high resolution camera on New Horizons, has been making observations from its unique vantage in the outer solar system. It has obtained light curves of Pluto, Uranus, Neptune, Triton, and Makemake, and the data to construct light curves have been obtained for several other Kuiper belt objects. RALPH and MVIC, other cameras aboard New Horizons, have also been studying Uranus and Neptune. ALICE, which studies ultraviolet light, is making observations of the interplanetary medium, and the fields and particles instruments are now being used even during hibernation, with their data stored for downlink after wakeup. The limiting factor on cruise science is the fact that New Horizons cannot transmit data as fast as it used to because of its increasing distance from the Sun. Presently, the data rate is down to 3 kilobits per second.
Planning for the flyby continues, as does the search for Kuiper belt flyby targets. The New Horizons trajectory is such that any Kuiper belt objects it might be able to reach after passing by Pluto would currently be seen from Earth against the backdrop of the dense star field of Sagittarius, making the search exceedingly difficult. The best known target is 1994 JR1, a small (127 kilometers in diameter) object with a 2:3 orbital resonance with Neptune. Choosing this target would have a downside: the encounter would be not long after Pluto so would require a significant trajectory change, which would use up more fuel than the project would like to use. Thus, the search continues, both for flyby targets, as well as other Kuiper belt objects, Neptune Trojans, and Centaurs, for which New Horizons could obtain high-phase light curve data. [New Horizons' unique position in the outer solar system allows it to view these objects at much higher Sun-object-spacecraft angles than we ever get to see from Earth, and the way the objects reflect light at different angles can tell us about the structure of their surfaces.]
In a related presentation, Pamela Gay, of the Zooniverse project (a massive citizen science initiative that has amateurs cataloging, among other things, lunar features and galaxies), proposed releasing the search data to the public to speed the search through the data. The way the process would work is something like this: An amateur thinks he or she has found an object moving between images. They will alert Zooniverse, which will forward the finding to five more amateurs. If most of them affirm it, it will go to seven more amateurs. Once it clears that hurdle, it will be forwarded to a professional. This will protect the project from being swamped by spurious claims from the overeager and provide a great opportunity for public participation. The project seemed very receptive.
Work is also being done to look for Plutonian rings in the orbits of Nix and Hydra, if they exist. Present data shows that if they do exist, they must be extremely faint. Efforts are also being made to model the dust environment in the Plutonian system.
The New Horizons mission is one of the most exiting missions ever flown, and, as the flyby approaches, the pace of things is speeding up soon. It has already sent back enough data to put it on the map, and its primary purpose has yet to be realized. Stay tuned!