Countdown: NASA's First Attempt to Loft the New Horizons Probe

NASA's first attempt to launch its New Horizons spacecraft on a more than nine-year mission to Pluto ended in a scrub Tuesday less than three minutes before its planned liftoff.

High winds thwarted the attempted the attempted space shot, preventing New Horizons and its Lockheed Martin-built Atlas 5 booster from launching during a window that stretched between 1:24 p.m. EST and 3:23 p.m. EST (1824-2023 GMT).

Here's how the day's countdown unfolded beginning with the most recent update:

UPDATE: 3:25 p.m. EST

Scrub! Launch officials scrubbed today's launch of the Pluto-bound New Horizons spacecraft due to high winds at the probe's Cape Canaveral launch pad.

The scrub occurred just with just two minutes and 42 seconds remaining in the countdown, when weather officers detected winds blowing at 33 knots - the maximum limit for the New Horizons spacecraft and its Atlas 5 rocket.

Flight controllers are now preparing New Horizons and its Atlas 5 rocket for a 24-hour turnaround. The spacecraft is now set to launch on Jan. 18 at 1:16 p.m EST (1816 GMT). Like today, the spacecraft has a one-hour and 59 minute launch window tomorrow that closes at 3:15 p.m. EST (2015 GMT).

A wrap up of today's scrubbed launch attempt can be found by clicking here.

UPDATE: 3:19 p.m.EST

The countis T-4 minutes and counting for NASA's NewHorizons mission to Pluto. The spacecraft is set to launch at 3:23 p.m. EST(2023 GMT).

After aseries of delays, primarily due to high winds, launch officials are once againpoised to loft the New Horizons spacecraft on a mission to the planet Pluto andbeyond.

Flightcontrollers are hopeful that the wind speeds at New Horizons' Cape CanaveralAir Force Station launch pad will remain below the acceptable limit, but willscrub the space shot if they get too high.

UPDATE: 3:05 p.m.EST

NASA hasagain retargeted its launch time for the Pluto-bound NewHorizons spacecraft to 3:23 p.m. EST (2023 GMT) - the end of today's flightwindow - in order to better understand strong ground winds at the probe's CapeCanaveral Air Force Station launch site.

Strongwinds, both on the ground and at upper levels, have been a cause of concern forflight controllers throughout today's countdown. While launch officials areconfident that the upper level windows are within the acceptable boundaries,they need more time to evaluate ground level winds, NASA officials said.

Wind speedson the ground at New Horizon's Complex 41 launch pad have danced around theupper limit - 33 knots - set by launch guidelines. Tucked inside its LockheedMartin-built Atlas 5 rocket, New Horizons was slated to launch at 1:24 p.m. EST(1824 GMT).

If thespacecraft misses today's launch window, the next window opens on Wednesday,Jan. 18. New Horizons has daily launch windows running through Feb. 14, butmust launch by Feb. 2 in order to take advantage of a Jupite rflyby next yearthat could shave years of its Pluto-bound journey.

UPDATE: 2:45 p.m.EST

NASA hasonce more reset the launch of its New Horizons Pluto probe. The spacecraft isnow set to launch at 3:05 p.m. EST (2005 GMT).

High groundand upper wind speeds have dogged today's launch countdown for the New Horizonsprobe and its Atlas 5 rocket. All other concerns, including a tracking stationproblem and a liquid oxygen vent glitch, have been resolved.

Flightcontrollers must launch New Horizons by 3:23 p.m. EST (2023 GMT), when today'swindow closes, or reset for tomorrow. There is a launch window for New Horizonseach day through Feb. 14, though a liftoff by Feb. 2 will shave three years offthe spacecraft's trip to Pluto.

UPDATE: 2:27 p.m.EST

A newlaunch time has been set for 2:50 p.m. EST (1950 GMT) for NASA's New HorizonsPluto probe due to a problem with the agency's Deep Space Network (DSN), NASAofficials said.

The DSNarray of radio antennas situated around the globe was not initially expected tobe ready for a 2:30 p.m. EST (1930 GMT), though apparently is now back online.The delayed launch time will allow extra checks to ensure the network, whichtracks spacecraft on deep space missions, is ready for today's liftoff.

NASA's NewHorizons spacecraft is slated to explore Pluto and its moons during a July 2015flyby, meeting the planet at a distance of about three billion miles fromEarth.

Today's launchwindow extends until 3:23 p.m. EST (2023 GMT).

UPDATE: 2:10 p.m.EST

A trackingstation required to launch NASA's NewHorizons on its mission to Pluto has gone offline, NASA officials said.

Thestation, based in Antigua, is required to monitor the launch of New Horizonsatop its Atlas 5 booster, but suffered a glitch with its command transmitter,NASA spokesperson Bruce Buckingham said.

Launchcontrollers are confident the station will be back online by 2:20 p.m. EST(1920 GMT), about 10 minutes before today's planned liftoff. High wind speedscontinue to be a concern.

NASA's NewHorizons spacecraft is the first probe ever built to visit Pluto, its moons andthe Kuiper Belt objects beyond the planet's orbit. The spacecraft's launchwindow closes at 3:23 p.m. EST (2023 GMT) today, though additionalopportunities will occur daily through Feb. 14.

UPDATE: 2:00 p.m.EST

Wind speedsboth on the ground at at high altitudes continue to cause concern for flightcontrollers overseeing today's launch of NASA's NewHorizons spacecraft destined for Pluto.

Flightcontrollers are now aiming at a 2:30 p.m. EST (1930 GMT) launch time. Earlier,high altitude winds were reportedly stronger than launch criteria allow, thoughweather officers are awaiting data from their latest round of balloon monitors.Ground level winds were gusting very close to the upper limit, 33 knots,allowable for an Atlas 5 launch.

Today'slaunch window will close at 3:23 p.m. EST (2023 GMT).

UPDATE: 1:45 p.m.EST

NASA nowhopes to launch its NewHorizons spacecraft at 2:10 p.m. EST (1910 GMT) today, pushing the spaceshot back a second time in less than one hour due to concerns of high winds.

Originallyset to launch at 1:24 p.m. EST (1824 p.m. EST) today, the Pluto-bound NewHorizons probe and its Atlas 5 booster was pushed back to 1:45 p.m. EST (1845GMT) to allow additional time to study wind conditions and vent valve glitch onthe rocket's first stage.

Flightcontrollers have been tracking wind speeds throughout today's launch countdown.Winds have been blowing steadily at 25 knots, with gusts reaching - andsometimes surpassing - the launch's 33-knot limit.

Today'slaunch window closes at 3:23 p.m. EST (2023 GMT).

UPDATE: 1:20 p.m.EST

Flightcontrollers have pushed the launch of NASA's Pluto-bound NewHorizons spacecraft back just over 15 minutes to allow additional time towork a pair of ongoing issues.

NewHorizons is now set to launch at 1:45 p.m. EST (1845 GMT) today. The extra timewill allow engineers more time to study a finicky liquid oxygen fill and drainvent valve, which appears to working as expected. The added time will also allowweather officers a chance to track wind speeds at New Horizons' launch site.

Launchcontrollers have been concerned that gusts of wind could exceed their launchparameters for today's planned space shot.

NewHorizons was originally set to launch at 1:24 p.m. EST (1824 GMT) today - theopening of its nearly two-hour launch window. That window closes at 3:23 p.m.EST (2023 GMT). The Pluto probe has a launch window each day through Feb. 14,though mission scientists hope to loft the spacecraft by Feb. 2 in order toswing past Jupiter next year and snag a gravity boost towards Pluto.

UPDATE: 1:10 p.m.EST

Thecountdown for NASA's Pluto-bound NewHorizons spacecraft has paused at T-4 minutes for a scheduled 10-minutehold before proceeding with today's planned launch.

NewHorizons is set to launch atop its Atlas 5 booster at 1:24 p.m. EST (1824 GMT),though engineers are studying a valve issue with the spacecraft's booster. Flightcontrollers are also watching high wind speeds at the probe's Launch Complex 41launch pad at Cape Canaveral Air Force Station.

UPDATE: 1:00 p.m.EST

Engineersare working a valve glitch with the Atlas 5 booster set to launch NASA'sPluto-bound NewHorizons spacecraft later today, one of two issues launch controllers arewatching in preparation for the planned space shot.

Missionmanagers are studying a whether a fill and drain valve for one of the rocket'sliquid oxygen tanks will close as required for today's launch. Readings from atest of the liquid oxygen vent valve were not as expected, mission controllersreported.

Meanwhile,weather officers continue to monitor winds at New Horizons' launch site at CapeCanaveral Air Force Station. Winds are blowing at a steady 25 knots with gustsreaching 33 knots, the upper limit according to Atlas 5 flight rules, NASAofficials said.

With justminutes remaining in the launch countdown for New Horizons, flight controllerscontinue to work toward a 1:24 p.m. EST (1824 GMT) liftoff.

UPDATE: 12:50 p.m.EST

Less than30 minutes remain in the countdown to launch NASA's Pluto-bound NewHorizons spacecraft. A built-in hold in the countdown will occur at T-fourminutes.

NewHorizons is on track to launch from Cape Canaveral Air Force Station's Complex41 at 1:24 p.m. EST (1824 GMT). Aside from high wind gusts, which weatherofficials continue to track, the outlood looks good for today's space shot,NASA officials said.

UPDATE: 12:30 p.m.EST

Pad workershave nearly completed loading liquid hydrogen propellant aboard the upper stageof NASA's NewHorizons spacecraft's Atlas 5 rocket.

Launchcontrollers are watching local wind speeds closely as they continue to prepareNew Horizons' Atlas 5 rocket for flight.

UPDATE: 12:15 p.m.EST

Engineerscontinue the loading of liquid oxygen aboard the Atlas 5 booster for NASA's NewHorizons spacecraft set to launch toward Pluto today.

High windspeeds continue to be a concern for today's launch. NASA spokesperson BruceBuckingham said winds are blowing steadily at about 25 knots at New Horizons'sCape Canavaral Air Force Station launch site. But gusts have reached 35 knots,just over the 33 knot limit for today's planned space shot, he added.

An updateon weather conditions at and above New Horizons' Complex 41 launch pad isexpected shortly.

NewHorizons is set to launch at 1:24 p.m. EST (1823 GMT) today, but does have someroom for delay if needed. Today's launch window closes at 3:23 p.m. EST (2023GMT).

UPDATE: 11:57 a.m.EST

NewHorizons principal investigator Alan Stern said the timing of today's launchis particularly apt.

Thespaceflight is a fitting tribute for astronomer Clyde Tombaugh, who discovered Plutoin 1930 and died nine years ago today, almost to the hour of New Horizons'planned liftoff, Stern said.

Tombaugh'swife Patsy and two grown children have traveled to Cape Canaveral to watchtoday's planned launch.

Meanwhile,pad engineers have just about filled the Centaur upper stage of New Horizons'Atlas 5 rocket with liquid oxygen and will have to top the booster offperiodically as it boils away. The rocket's first stage is about 10 percentfull with the supercold liquid.

UPDATE: 11:55 a.m.EST

As theclock ticks down toward the launch of NASA's Pluto-bound New Horizonsspacecraft, engineers have begun loading liquid oxygen propellant into theprobe's Atlas5 booster. The rocket's Centaur upper stage is almost filled with thecryogenic liquid.

Once bothAtlas 5 rocket's first stage and its Centaur upper stage are filled with liquidoxygen, engineers will begin loading liquid hydrogen into their respectivetanks, NASA officials said.

UPDATE: 11:35 a.m.EST

Today'scountdown for the launch of NASA's Pluto-bound New Horizons spacecraftcontinues to go smoothly.

Launch padworkers have begun loading supercold liquid oxygen aboard New Horizons' Atlas 5booster's upper stage is and about 13 percent complete, NASA officials said.The Lockheed Martin-built rocket carries five strap-boosters that will generatealmost three million pounds of thrust at launch, slinging New Horizons on whatNASA officials have said is their fastest mission to date.

A Centaurupper stage is designed to kick in once New Horizons reaches space and performtwo burns to send New Horizons on its way. Once liquid oxygen loading of theCentaur is complete, pad workers will load the chilled liquid into the rocket'sAtlas stage, then proceed to load liquid hydrogen aboard the rocket.

UPDATE: 11:15 a.m.EST

Omar Baez,NASA's launch manager, said today's launch of the New Horizons Pluto probe isproceeding smoothly with no technical issues so far. The countdown has pickedup at T-2 hours.

Baez saidflight controllers are watching the wind speeds at New Horizons' launch site atComplex 41 at Cape Canaveral Air Force Station in Florida. Wind speeds werereported at about 29 knots, still below the limit of 33 knots, Baez said.

NASA'sKennedy Space Center director Jim Kennedy said New Horizons is carrying Floridaquarter coin to honor its launch site.

UPDATE: 11:00 a.m.EST

NASA's firstspacecraft to the planet Pluto is poised to launch spaceward atop its Atlas 5booster.

The NewHorizons spacecraft is set to lift off from its launch pad at Cape CanaveralAir Force Station in Cape Canaveral, Florida at 1:24 p.m. EST (1824 GMT),though today's flight window will stretch until about 3:23 p.m. EST (2023 GMT).New Horizons is slated to spend about nine years flying toward Pluto, duringwhich it is expected to swing past Jupiter next year. If all goes well, thespacecraft is designed to reach Pluto as early as July 2015.

"It'sa great day," NASA chief Michael Griffin said today at the agency'sKennedy Space Center (KSC) near the launch site. "This is a milestoneevent for NASA."

About thesize of a piano, New Horizons carries seven primary science instruments poweredby a radioisotope thermal generator (RTG), which converts heat from decayingpieces of plutonium into energy for spacecraft systems.

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at:

Tariq Malik

Tariq is the Editor-in-Chief of and joined the team in 2001, first as an intern and staff writer, and later as an editor. He covers human spaceflight, exploration and space science, as well as skywatching and entertainment. He became's Managing Editor in 2009 and Editor-in-Chief in 2019. Before joining, Tariq was a staff reporter for The Los Angeles Times covering education and city beats in La Habra, Fullerton and Huntington Beach. In October 2022, Tariq received the Harry Kolcum Award for excellence in space reporting from the National Space Club Florida Committee. He is also an Eagle Scout (yes, he has the Space Exploration merit badge) and went to Space Camp four times as a kid and a fifth time as an adult. He has journalism degrees from the University of Southern California and New York University. You can find Tariq at and as the co-host to the This Week In Space podcast with space historian Rod Pyle on the TWiT network. To see his latest project, you can follow Tariq on Twitter @tariqjmalik.