TECH

New Horizons set to write book on Pluto

James Dean
FLORIDA TODAY
Charles Tatro was a member of the Kennedy Space Center team that helped ready the New Horizons mission for launch from Cape Canaveral in January 2006. The spacecraft will make its closest approach to Pluto Tuesday morning. Tatro is holding a bag of blue M&Ms with New Horizons printed on them that was given to him in 2006 by the Johns Hopkins team as a memento of the launch. He plans to open the M&Ms and eat them Tuesday.

At the risk of an upset stomach, Chuck Tatro plans to make good on a nearly decade-old promise Tuesday.

As part of the Kennedy Space Center team that helped ready the New Horizons mission for launch from Cape Canaveral in January 2006, Tatro on launch day received a small bag of blue, mission-themed M&Ms from the spacecraft builders.

"I said, 'I'm going to keep those on my desk and I'm going to open those M&Ms and eat them when you arrive at Pluto,' " Tatro remembers.

That day has finally come with the New Horizons probe, after a nine-and-a-half-year journey spanning more than 3 billion miles, set to zip close past Pluto and its five known moons at 7:49 a.m. Tuesday.

The flyby within 7,800 miles of Pluto's surface will offer the first detailed look at what for decades was considered the solar system's smallest and outermost planet, before its 2006 demotion to dwarf planet status.

Until recently, the best picture of Pluto consisted of pixels, some brighter and some darker, captured by the Hubble Space Telescope.

In the early morning hours of July 8, 2015, mission scientists received this new view of Pluto—the most detailed yet returned by the Long Range Reconnaissance Imager (LORRI) aboard New Horizons. The image was taken on July 7, when the NASA spacecraft was just under 5 million miles (8 million kilometers) from Pluto. This view is centered roughly on the area that will be seen close-up during New Horizons’ July 14 closest approach. This side of Pluto is dominated by three broad regions of varying brightness. Most prominent are an elongated dark feature at the equator, informally known as “the whale,” and a large heart-shaped bright area measuring some 1,200 miles (2,000 kilometers) across on the right. Above those features is a polar region that is intermediate in brightness.

But New Horizons will snap images Tuesday with such high resolution that if they were taken over New York City, they would reveal major roads, wharves along rivers and ponds in Central Park.

"This is true exploration," said Alan Stern, lead scientist for the $720 million mission, during a presentation to KSC employees last month. "We're going to write the book on the Pluto system."

The system has grown since New Horizons, which is roughly the size of a baby grand piano, blasted off from Cape Canaveral Air Fore Station atop the most powerful Atlas V rocket available, becoming the fastest spacecraft ever launched.

Two more small moons, Styx and Kerberos, were discovered in 2011 and 2012. They joined the large moon Charon, which has the diameter of Texas, and two moons found shortly before the launch, Nix and Hydra.

Frigid, dimly-lit Pluto is the brightest representative of a new class of small planets and objects in the doughnut-shaped Kuiper Belt, which is now seen as the "third zone" of the solar system beyond the inner rocky planets and outer gas giants.

More than 1,500 mostly smaller objects identified in the belt just since the 90s hold scientific interest as relics from the era of planet formation, icy and rocky building blocks of planets of a sort that may have delivered water and the raw material for life to Earth.

"They've been in this great deep freeze all along for 4 billion years, so they should be much more pristine, primordial samples of the original material out of which the planets were made," said Stern. "No one's ever been to one of them."

As the first mission there, New Horizons' seven instruments will map Pluto and its moons and analyze their surface and interior compositions and temperatures. They will sample Pluto's thin but complex atmosphere — "close enough to actually taste it," said Stern — to determine its makeup and how quickly it is escaping.

The very different Charon is believed to have no atmosphere and a more uniform, gray surface that contrasts with reddish-hued Pluto, whose surface includes large, recently spotted features nicknamed the "heart" and the "whale."

Getting to Pluto has taken patience.

"You've got to really be into delayed gratification if you want to be in on this mission," Stern told reporters recently.

Approved in 2001 as a top priority by the National Academy of Sciences, the spacecraft was built in just four years.

Once it arrived at the Cape, Tatro managed an integration team that hooked up and tested a plutonium-powered battery and an extra solid kick stage atop the rocket. Hurricane Wilma interrupted launch preparations.

Missing the 35-day launch window would have extended the Pluto journey to 14 years. But after two weather delays, the powerful rocket made the small spacecraft the fastest ever launched, speeding from Earth at 36,000 mph.

"It was really zooming," said Tatro.

New Horizons passed the moon in nine hours, 10 times faster than an Apollo mission. It flew by the orbit of Mars in less than three months and past Jupiter in just 13 months — the only planet to provide a gravity assist along the way.

The spacecraft spent much of the mission in hibernation, until a final wake-up call in December set the stage for a months-long approach that has produced increasingly detailed images as New Horizons closes in on Pluto.

Flying at 31,000 mph, Tuesday's flyby will last just about 30 minutes as the spacecraft speeds through a narrow target zone. After more than nine years, the timing can't be off by much more than a minute.

"We're doing a lot of things at once, it's very fast-paced," said Stern. "There's no second chance."

With Pluto now 32 times farther from the sun than Earth, spacecraft communications take four-and-a-half hours one-way.

It will not be until just after 9 p.m. Tuesday that the mission team hopes to hear New Horizons "phone home" to confirm its health and location.

"If it gets knocked out by a piece of debris, it just won't answer us that night," said Stern. "It's going to be an interesting day."

Assuming all is well, New Horizons will take 16 months to downlink its observations, ensuring a steady stream of surprises for scientists long after the flyby.

NASA could approve an extended mission that flies by one more small Kuiper Belt object in 2019. New Horizons eventually will exit the solar system like Voyager 1.

Much has changed since the mission launched.

NASA retired the space shuttle program and KSC embarked on a major transition. Tatro's Launch Services Program helped send a large rover to Mars and an orbiter to Jupiter, among other missions, and is preparing to launch a Mars lander. Tatro has seen his three sons grow up and enter high school and college.

Last month, using NASA's "Pluto Time" guide, the 56-year-old Titusville resident gathered his kids outside at dawn to experience what the light would be like at noon on Pluto.

Soon it will be time to open his sealed, cellophane bag of New Horizons M&Ms, which he may share with colleagues celebrating the mission's arrival at Pluto.

The few dozen M&Ms appear surprisingly well-preserved after more than nine years as a desk ornament.

"They may taste pretty bad," he said. "I think they'll be OK."

Contact Dean at 321-242-3668 or jdean@floridatoday.com. And follow on Twitter at @flatoday_jdean and on Facebook at facebook.com/jamesdeanspace.

Pluto flyby

NASA's New Horizons probe will be closest to Pluto at 7:49 a.m. Tuesday and "phone home" to Earth around 9 p.m. the same day. Floridatoday.com will show NASA's live video stream from mission control during both events. Check back for updates as the flyby gets closer.

MORE online

Go to floridatoday.com to watch a video about the mission and gain some perspective on how far New Horizons has traveled.

Pluto facts

• Discovered in 1930 by American astronomer Clyde Tombaugh

• Five known moons: Charon, Nix, Hydra, Styx and Kerberos

• Average distance from sun is 3.7 billion miles; current distance from Earth nearly 3 billion miles

• Circles sun once every 248 Earth years in oval-shaped orbit

• From Earth, Pluto appears 50,000 times fainter than Mars

• Estimated surface temperature is minus 387 degrees Fahrenheit

• Surface gravity about 6 percent of Earth's

• Tenuous but complex atmosphere made mostly of nitrogen, with traces of methane, carbon monoxide and some heavier hydrocarbons

Source: NASA

New Horizons facts:

• Launched Jan. 19, 2006, from Cape Canaveral Air Force Station on Atlas V rocket

• Launch weight of 1,054 pounds, fully fueled

• Roughly size of a baby grand piano

• Powered by nuclear battery

• Seven science instruments

• Mementos on board include ashes of Pluto discoverer Clyde Tombaugh and Florida state quarter

• Closest Pluto flyby at 7:49 a.m. Tuesday

Source: NASA