New Horizons: No News Is Good Snooze
I haven’t written much on the unmanned New Horizons Mission to Pluto of late, mostly because there’s been little if anything to report. The spacecraft went behind the sun (from our point of view here on earth) at the end of December, and was out of contact for less than a week. That always drives the controllers a little nutz, but it is, of course, unavoidable for most deep space missions.
Thankfully for N.H., nothing happened. Moreover, not much has happened since, except routine maintenance. The weekly report is full of phrases like “…the spacecraft remained…”, “…the NH spacecraft returned to the nominal operations concept…”, “Spacecraft maintenance events…” and most importantly, “The spacecraft is healthy and operating nominally.”
As Newman would say, “Eeeexcelllllent”.
Last November N.H. thought it detected a “current overload”, which caused its nervous Autonomous Control System to make the spacecraft go into the fetal position and phone home with a little whimpered cry of “help”. Ground controllers were concerned enough to examine the event carefully. Very carefully. They came to understand in about a week that the over-current was an artifact of the configuration that the spacecraft was in, it was not serious at all in that it was not going to damage anything, and that Autonomy was overreacting. The next step was to create a new version of the Autonomy software that could handle the condition better. That version was tested and uploaded less than a month later.
Since then, N.H. has been monitored closely using the Deep Space Network of receiving antennas that listen to deep space missions (and chew up budgets). That same condition has reoccurred at least twice, but now Autonomy does not cause the spacecraft to have fits of panic. So the decision was made to let N.H. go into a passive mode on February 1, where nearly continuous monitoring won’t be necessasry. The DNS will check in every couple of weeks or so to make sure that N.H. is still sleeping peacefully.
In case you were wondering, New Horizons is long past Jupiter, and is most of the way to the orbit of Saturn (the planet itself is on the other side of the sun). It takes a signal sent from earth nearly an hour and a half to get to the spacecraft.