Pluto Space P-0

In case you might have missed it,

New Horizon’s encounter with Pluto today was absolutely, completely, 100% successful!

Needless to say, there was some excitement in the Willett household.

For truly monumental events, the Vuvuzela Of Victory must sing. Its joyous bellow can not be silenced.

Despite writing at length yesterday about how we would not be in any kind of contact with New Horizons at its moment of closest approach, making it somewhat of a non-event in terms of live action, I was up a couple hours early to watch the feed from the Johns Hopkins University Applied Physics Laboratory (JHUAPL). At “the moment” there was a countdown in the control room, a cheer, and then they got ready for a press conference.

2015-07-14 Last Pluto Pre-Flyby


The press conference released this photo, the one downlinked quickly last night, “highly compressed.” The pictures taken today (which we will see in dribs and drabs over the next few months) will be as much as one hundred times as detailed as this one. Clearly visible is the huge “heart” shape, which breaks the dark equatorial belt. Also visible are craters in the lower left, “hummock-like” formations in the lower right, a polar cap (some different type of ice, perhaps? nitrogen? methane?) at the top, a possible mountain range just above and to the left of the “heart,” and so on.

And this is the poor quality version of this photo, squeezed into a quick downlink of engineering data late last night.

Everyone said the right things at the 0815 EDT press conference before going to wait through the day. Many of the senior project scientists and engineers spent much of the day giving interviews and answering questions on Reddit, Twitter, Facebook, and other social media outlets. I know they did it because they love doing the outreach and showing their work to the public, but I wonder if they didn’t also do it to give them something to do to keep their minds off of what this evening would bring.

To recap, New Horizons was operating completely on its own, executing a pre-programmed sequence of spins, turns, and targeting to take hundreds of pictures and thousands of scientific measurements. Pluto is currently over three billion miles away, which is 4:26 in light travel time. In addition, New Horizons spent the hours near closest approach doing science and taking pictures, not stopping to send the data back to Earth.

So, this afternoon and evening the big question was, “Did New Horizons live?” Was it out there executing the commands so carefully crafted over years by the engineers on the ground? Was it humming along like a contented little robot, doing what it was designed to do, performing like a champion in its moment of triumph?

Or had something inexplicable gone wrong? Tearing through the Pluto system at 31,000 MPH, colliding with a piece of orbiting rock the size of a grain of sand could be a disaster. Hitting something the size of a marble would probably totally destroy her. Or had there been some software error, or hardware failure, something that might have caused the computer to lock up and reboot at a critical time? Engineers are really good at thinking up failure scenarios, in part to figure out how to plan ahead for them, but the ones you don’t know about can ruin your day.

2015-07-14-1737 DSN

Image: NASA / JPL / DSN

This evening we all sat watching as 20:53 EDT approached, waiting for the huge 63 meter antenna in Madrid, Spain to pick up the faint signal from New Horizon.

If all had gone according to plan, New Horizons should have sent a short “I’m alive!” or “phone home” message at 16:27 EDT. That message, trundling across the solar system at a piddling 186,000 miles per second should have been picked up by Madrid and passed on to the New Horizons team at JHUAPL.


Image: NASA / JPL Eyes On The Solar System

There’s the simulation, pointing at Earth, dumping a quick engineering data set. But would reality match the simulation, or had Murphy accompanied us to Pluto?

As we watched MOM (Mission Operations Manager) Alice Bowman talk to the DSN staff, watch her monitors, and then talk to her staff, her calls came quickly.

  • “Okay, we’re in lock with carrier” – the New Horizons carrier wave radio signal was being received and Madrid had locked onto it.
  • “Stand by for telemetry” – New Horizons was alive – but was it acting like it was supposed to or was something odd happening?
  • “In lock on symbols” – New Horizon was sending information at the rate and in the format expected if it were healthy and operating correctly.
  • “Okay, copy that, we’re in lock with telemetry with the spacecraft” – the “phone home” message was coming in as expected and the data was being received correctly.
  • Let the cheering and clapping commence! In the conference room, after a deep breath,
  • “Subsystems, please report your status as you get enough data” – the message contains status information on many spacecraft systems, each with its own set of specialists and flight controllers.
  • RF reports as nominal, “nominal signal to noise ratio for the telemetry.” New Horizons is communicating as expected, no problems.
  • Autonomy reports as nominal, “no rules have fired.” No alarms, no alerts, nothing unexpected to report.
  • CNDH reports as nominal, “we recorded the expected amount of data.” The big, solid-state memory banks built into the computers are as full as they’re supposed to be if everything went as planned.
  • GNC reports as nominal, “all hardware is healthy and we have a good number of thruster counts.” The pre-programmed “ballet” to point at one target after another went exactly as planned.
  • Propulsion reports as nominal, “tank pressure is 176.8.” There’s plenty of fuel left on board, as expected.
  • Power reports as nominal, “all hardware is healthy.” That RTG is cooking along just like it was designed to.
  • Thermal reports as nominal, “all temperatures green.” It’s cold way out here, but the right amount of cold.
  • “PI, MOM on Pluto One. We have a healthy spacecraft, we’ve recorded data of the Pluto system, and we’re outbound from Pluto.”
  • Time for the partying and celebrations to begin. New Horizons is alive and well, with a full load of data.

As soon as New Horizons was done sending its report multiple times (to make sure that we got it and got it correctly), it had (4:26 earlier) turned back away from Earth and started taking more pictures and data. The pace of the observations is starting to slow, and by tomorrow morning there will again be time for New Horizons to turn back to Earth and start sending back the data it’s stored.

Tomorrow afternoon at 15:00 EDT we’ll get the next press conference. If all continues to go as expected, we should see some of the first fantastic, high-resolution, close-up pictures of both Pluto and Charon. We should also get the first early results from the other scientific instruments.

It will take over sixteen months to downlink all of the data. We’ll get high priority data for the next two weeks, then go into a downlink of the “slow data.” It’s not a slower downlink speed, but data that was recorded at a slower rate during the flyby. This makes it easier to downlink, which will give the primary New Horizons operation team a chance to take a badly needed breather. Then, in September they’ll crank up the intensity again.

By November another part of the team will have looked more closely at possible secondary targets deep out in the Kuiper Belt. One will be chosen and a series of small course changes will be started in the hopes of flying by a Kuiper Belt planetesimal in four or five years. Doing so will depend on future funding and commitment by Congress and the President.

Congratulations to the PI (Primary Investigator) Alan Stern, the MOM (Mission Operations Manager) Alice Bowman, and the entire New Horizons team. I hope that you’re all getting a good night’s sleep tonight. You’ve earned it.

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