“It Worked.” Those are the words that form the last entry in my project notebook for the day of launch. Now, a day later, the spacecraft is already undergoing checkouts, and has been de-spun from its launch rotation rate of 68 RPMs to just under 20 RPMs. The spacecraft power system is producing almost exactly the wattage predicted pre-flight, and our thermal situation is good. No unexpected faults occurred during launch, and so far, the checkout procedures that mission control at APL have executed have gone well.

Initial trajectory solutions indicate our launch was almost perfect, needing just perhaps 20 meters/sec or so of makeup delta-V. This is far less than the 100 meter/sec we had budgeted for, meaning we have much more fuel for Pluto and Kuiper Belt encounters than our “3 sigma” planning had to allow for.

As I write these words, just 24 hours after launch, New Horizons is already approaching 1 million miles from Earth, which isn’t very far compared to the 3 billion miles it must travel to Pluto, but it’s a start and we are all very happy.

I’ll have much more to write next week. In the meantime, we hope you, like our team, are savoring yesterday’s success.

— Alan Stern