From: Southwest Research Institute
Posted: Sunday, January 22, 2006
Things are going well here at the APL MOC. New Horizons is operating virtually flawlessly. TCM 1a and 1b are planned for 28 Jan and 30 Jan, respectively, with a total delta-V of 18 m/s-- which is far smaller than the 92 m/s budgeted for pre-flight. Good news!
Today we are planning to complete the spacecraft's planned spin down to 5 RPM (was 68 RPM for the STAR-48 firing, is now 19.2 RPM after an open-loop burn on launch day). Once we slow it down this afternoon, we'll do the initial star track turn ons. Until then, we're still relying on the sun sensors and IMUs-- both of which are performing very well. The s/c temps are running a little hot, but that's just due to our attitude combined with our <1 AU helio distance (we're inside 1 AU because we launched near Earth's perihelion).
About the heliocentric distance, we will be inside 1 AU until late on 29 Jan UT. That makes us officially an inner planet mission for the first 10 days, I guess.
We will pass the orbit of Mars on 8 April, just a little after MRO gets there, and it had a 5.5 month head start.
FYI-- The C/A to Jupiter is going to be at approx 6 hrs UTC on 28 Feb 2007. A better number will be forthcoming, but that is good to an accuracy of better than an hour already. C/A is at 32 RJ. Because we have to slow down in TCM-a and TCM-1B by those 18 m/s, our third stage will beat us to Jupiter. However, because it will not hit the Pluto aim point, it will not beat us to Pluto (a relief-- can you imagine us having to be the second to Pluto after all this, having been beat by a derelict Boeing upper stage?). In fact, the projected C/A distance of the third stage to Pluto will be 213 million km (well over 1 AU), occurring on 15 Oct 2015.
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