If you thought the New Horizons spacecraft flyby of the Pluto system happened waaaay too fast and you’re pining for more images and data, you are in luck. What the spacecraft has been able to send back so far is just the tip of the icy dwarf planet, so to speak.
Starting tomorrow, Saturday, September 5, 2015, the spacecraft will begin an “intensive” downlink session that will last for a year or more, sending back the tens of gigabits of data the spacecraft collected and stored on its digital recorders during the flyby. What will come first are “selected high priority” data-sets that the science team has been anxiously waiting for.
“This is what we came for – these images, spectra and other data types that are going to help us understand the origin and the evolution of the Pluto system for the first time,” said New Horizons Principal Investigator Alan Stern. “And what’s coming is not just the remaining 95 percent of the data that’s still aboard the spacecraft – it’s the best datasets, the highest-resolution images and spectra, the most important atmospheric datasets, and more. It’s a treasure trove.”
Can I get a fist pump, all you Plutophiles?
— NASA New Horizons (@NASANewHorizons) August 27, 2015
Plus, every Friday from here on out, you can count on getting new, unprocessed pictures from the Long Range Reconnaissance Imager (LORRI) on the New Horizons project website. Here’s where you can find the images, and the next LORRI set is scheduled for posting on Sept. 11, so set your calendars.
It’s been 7 weeks since New Horions’ historic flyby of the Pluto system, and during this quick pass, the spacecraft was designed “to gather as much information as it could, as quickly as it could, as it sped past Pluto and its family of moons – then store its wealth of data to its digital recorders for later transmission to Earth,” said the mission team.
Why is it taking so long? The spacecraft runs on between 2-10 watts of power, and it had to prioritize on data collection during the flyby. The data has been stored on two onboard, solid-state, 8 gigabyte memory banks. The spacecraft’s main processor compresses, reformats, sorts and stored the data on a recorder, similar to a flash memory card for a digital camera.
One issue is the time it takes to get data from New Horizons as it speeds even farther away from Earth, past the Pluto system. Even moving at light speed, the radio signals from New Horizons containing data need more than 4 ½ hours to cover the 4 billion km (3 billion miles) to reach Earth.
But the biggest issue is the relatively low “downlink” rate at which data can be transmitted to Earth, especially when you compare it to rates now common for high-speed Internet surfers.
During the Jupiter flyby in February 2007, New Horizons data return rate was about 38 kilobits per second (kbps), which is slightly slower than the transmission speed for most computer modems. Now, after the flyby, the average downlink rate is going to be approximately 1-4 kilobits per second, depending on how the data is sent and which Deep Space Network antenna is receiving it. Sometimes, when possible, the spacecraft will be able to increase the rate by downlinking with both of its transmitters through NASA’s largest antennas of the DSN. But even then, it will take until late 2016 to send Pluto flyby data stored on the spacecraft’s recorders.
Patience you must have, my young padawan.
“The New Horizons mission has required patience for many years, but from the small amount of data we saw around the Pluto flyby, we know the results to come will be well worth the wait,” said Hal Weaver, New Horizons project scientist.
The data received by the DSN (you can watch the live data link happen on the Eyes of the Solar System DSN NOW page) will be sent to the New Horizons Mission Operations Center at the Applied Physics Lab a Johns Hopkins University, where data will be “unpacked” and stored. Then mission operations and instrument teams will scour the engineering data for performance trend information, while science data will be copied to the Science Operations Center at the Southwest Research Institute in Boulder, Colorado.
At the Science Ops Center, data will pass through “pipeline” software that converts the data from instrumental units to scientific units, based on calibration data obtained for each instrument. Both the raw and calibrated data files will be formatted for New Horizons science team members to analyze. Both the raw and calibrated data, along with various ancillary files (such as documents describing the pipeline process or the science instruments) will be archived at the Small Bodies Node of NASA’s Planetary Data System.
More info: New Horizons