Three months ago I asked the NASA Science Mission Directorate (SMD) some simple questions regarding possible changes to the New Horizons encounter with Pluto based on recent data indicating debris in the region. I was told that I'd get a prompt reply. SMD PAO finally got around to responding to me today after three months of silence. One would think that these answers would be simple to provide - and based on standard mission operating procedures. Guess not.



Will NASA be spending additional funds for additional telescope observations of Pluto? If so, how much will these observations cost, what budget pays these costs, what telescopes/spacecraft will be used, and how long will these observations be conducted?



SMD: No. NASA always carries reserves on flight missions to handle unforeseen circumstances such as this. NASA plans to spend approximately $500K from both New Horizons and New Frontiers reserves on telescopic observations to determine if a risk to the spacecraft exists. The New Horizons Project is coordinating an observation plan that to date has utilized the Hubble Space Telescope orbiting Earth and the Keck telescope in Hawaii. The individual observations are relatively brief and are scheduled to occur throughout the year based on the availability of the telescopes and optimal geometry between Earth, Pluto, and the Sun.



When will contingency plans for changing the trajectory of New Horizons at Pluto be finalized?



SMD: We don't yet know if any change in the trajectory is needed. First we need to finish characterizing the size and spatial distribution of the dust in the Pluto system, which we are doing using a combination of telescopes and complex modeling of the orbital mechanics occurring at Pluto. Then we will assess the risk that dust poses to the New Horizons spacecraft. NASA's experience with the Cassini spacecraft and its operation near Saturn's dusty rings will be helpful during that assessment. This work will not be complete until fall 2013. In parallel with this work, the New Horizons project is evaluating a series of alternate trajectories, comparing their impact to the science observations, spacecraft resources, data downlink, etc. Risks need to be fully considered in that as well, so that effort can't be completed until the dust characterization and risk assessment is complete. We can wait until just a few weeks before the Pluto encounter to make changes to the trajectory. Thanks to the diligence of the New Horizons team, we have plenty of time to consider contingency plans.



Who (Individual, agency) makes the final decision as to whether New Horizons continues on its original trajectory or if that trajectory is modified?



SMD: The PI of the New Horizons mission will provide his recommendation to NASA. The SMD Associate Administrator will make the final decision.



When was NASA notified by New Horizons mission team that the original flight trajectory was in jeopardy due to debris concerns?



SMD: We don't know if the planned trajectory is in jeopardy. The New Horizons project informed NASA Headquarters in the spring of 2012 of their concerns, at the same time presenting a thorough plan to determine if the concern was valid. NASA and the New Horizons team have been executing that plan since then.

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