Early this morning, NASA’s New Horizons probe made its closest approach to the Pluto-Charon system. Now after a full day of science and a long, long wait for the signal to reach Earth, we’ve received word that our daring (and darling!) probe is still alive.

After its close approach to Pluto this morning, the inconsiderate New Horizons spacecraft was too busy doing science to call home. Now it’s finally collected enough data to take a break, slew around towards Earth, and send us a quick “I’m alive!” message. The immense travel times mean the probe actually sent its message 4.5 hours before we’ll receive it here on Earth. We’re expecting to get confirmation of the probe’s survival by 9:02 pm ET.


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The Story So Far: The New Horizons probe has been dashing out to Plutofor nearly a decade. After waking up this December, the flyby of the Pluto-Charon system officially began soon after. The closest approach was early this morning at 04:49:57 PT (11:49:57 UTC / 07:49:57 ET). Now after a long day of waiting (with a bit of science!), we’re waiting to hear back that it survived and is still producing amazing science. You can follow along with a model of what the New Horizons probe is doing in real time using the NASA Eyes on Pluto app, or browse our extensive mission coverage here.


The Call Home: The communications pass will begin at 17:53 PT (July 15 00:53 UT / July 14 20:53 ET), with the mission team receiving the signal inside the next nine minutes by 18:02 PT. You’ll know it as a success by the jubilant shouting, bear hugs, and general noisiness on the live stream. The communications downlink will end seven minutes later, with New Horizons going silent by 18:09 PT.

The call home will just be spacecraft health information, no scientific data. The first message will be enough to tell us that New Horizons is still alive; the rest of the message will run through the health of all the instruments to confirm that nothing was damaged by a stray bit of debris pinging something vital. To be clear: we expect everything to be fine. NASA’s Principal Investigator Alan Stern has listed the odds of a mission-ending problem as being on the order of 1 or 2 in 10,000. Once the probe has reassured its fretting humans that it’s doing just fine in deep space, it will resume scientific observations of the Pluto-Charon system.


Live Blog starting at 5:30pm PT: I’m bouncing off the walls chanting “Pluto Pluto Pluto PLUTO!” like a kid impatiently waiting to open presents. I’ll be continuing through the post-contact hiatus until the press briefing at 6:30pm PT, and through the briefing. Luckily, I’ve been stockpiling all sorts of stories, science, and trivia to keep us busy while we wait!

This gorgeous shot of Pluto will get a stereo-twin downlinked early on Wednesday morning. Image credit: NASA/JHUAPL/SWRI


Patience is essential: New Horizons will take another break from science early morning moments before 4am PT (10:59 UT/06.59 ET) to spend 1.5 hours sending home brand-new images. All three images were taken by the higher-resolution but black-and-white only instrument LORRI:

  • Charon: The largest moon of Pluto was imaged at just 466,000 kilometers away for a resolution of 2.3 kilometers per pixel. This will be the best single-frame photograph of Charon available during the initial downlinks.
  • Pluto: The star of the show was also captured, this time from just 778,000 kilometer away for a resolution of 3.9 kilometers per pixel. This image is a partner to the one downlinked at the start of the close approach, creating a steropair for 3-dimensional viewing.
  • Hydra: One of Pluto’s smaller moons (probably the 3rd largest after Nix, unless it’s unusually dull for its size) will finally get a closeup with its first solo portrait taken from a range of 645,000 kilometers. This will give it a resolution of 3.2 kilometers per pixel.


Because New Horizons can only collect scientific data or communicate with Earth, not both at the same time, we won’t be seeing all of the photographs taken during the close approach for up to 16 months.

Even scientists are sentimental: NASA plays custom-selected wake-up songs every morning on the International Space Station. To wake up New Horizons, they picked Russel Watson to sing “Faith Of The Heart.” Sound familiar? That’s also the theme song from Star Trek: Enterprise. Alas, they didn’t select “A Whole New World” from Aladdin despite it containing the lyrics, “with new horizons to pursue.” What would you put on a New Horizons playlist?

New Horizons is tiny! The probe is remarkably small for a spacecraft: it’s about the dimensions and mass of a piano. While this would still be problematic if it smashed into your car, it’s only half the mass of the Mars Curiosity rover. The launch weight was just 478 kilograms (1,054 pounds); 77 kilograms (170 pounds) of hydrazine propellant (now partly burned) and a 30-kilogram (66-pound) science instrument payload.


New Horizons brought plutonium to Pluto. The radioactive element was named for the dwarf planet, and is used to power the probe out in deep space where solar panels would be far less effective. The probe was launched during an ongoing crisis in obtaining plutonium-238, so managed to use the barest minimal amount to power the probe’s radioisotope thermal generator (RTG). The generator can produce approximately 200 watts of power. The nuclear battery transforms heat into electricity, and is long-lived enough to power the probe into the 2030s if we keep funding NASA’s mission operations budget.

You can track which space explorers the Deep Space Network is chatting with in real time on the NASA Eyes website. Image credit: NASA/Joel Kowsky


“Stand by for telemetry.” It’s happening! The Deep Space Network antenna in Madrid is ready and waiting to hear from our distant probe. Are you ready to start squeaking in joy? Because I am. I really, really am.

Jubilation in the Mission Operations Center (MOC) of the Johns Hopkins University Applied Physics Laboratory (APL) as the New Horizons spacecraft makes its first call home after the Pluto flyby on July 14, 2015. Image credit: NASA/Bill Ingalls


FUCK YEAH WE HAVE A SPACE PROBE! All that cheering and clapping? New Horizons is alive enough to phone home. Now let’s hear how it’s doing. YAY!!!!!

Is nominal a good thing? “Nominal” is beautiful. Nominal is perfect. Nominal is everything showing up exactly as we want it to. Amusingly, the team has been unsatisfied with calling things just nominal, and has been substituting “extremely nominal.”


A brief, informal translation of selected call-ins:

LOCK IN WITH CARRIER: New Horizons is still alive.
LOCK IN WITH TELEMETRY: The probe had something to tell us.
AUTONOMY NOMINAL: The probe didn’t throw any errors (like the retroactively-terrifying holiday glitch).
SSR POINTERS NOMINAL: The probe successfully recorded spectra. PROPULSION IS NOMINAL PRESSURE IS 176.8: The engines are healthy, and still have juice in them if, say, we want to visit another Kuiper Belt Object.
THERMAL REPORTS NOMINAL ALL TEMPERATURES GREEN: The on-board nuclear reactor is still good to keep powering the probe for decades.

MOM ON PLUTO-1 WE HAVE A HEALTHY SPACECRAFT WE RECORDED DATA ON THE PLUTO SYSTEM AND WE ARE OUTBOUND FROM PLUTO: New Horizons is one perfect, beautiful, well-behaved glorious probe happily heading out farther to keep exploring deep space.


Overall translation: Not only does the spacecraft look good, but it successfully collected and stored all its data for later downlink to Earth. Science team member Leslie Young also confided in Planetary Society reporter Emily Lakdawalla that the telemetry also included realtime PEPSSI energetic particle data, providing the tiniest hint of science along with the spacecraft health data.

New Horizons Principle Investigator Alan Stern has the “Fuck yeah!” victory strut down perfectly. Image credit: NASA/Bill Ingalls


Pluto is populated by dark gods. Every planetary body has a theme for naming its surface features. As god of the underworld, Pluto’s theme is dwellers of the underworld. That means the innocent whale we spotted in earlier images now has an informal name amongst the mission scientists: Cthulhu. I’m grateful our probe wasn’t an unwilling sacrifice to the elder god!

The streets are alive with the sound of celebration! It’s not often that a bit of science news captures the collective imagination, but in the streets of downtown Vancouver there’s at least a few die-hard space fans. Outside my window is joyous car-honking and screams of PLUUUUTOOOO!!! These are my people.

Pluto is damn cold. Yesterday, we confirmed Pluto has a methane and nitrogen ice cap on its north pole, but is it ice like anything we know? At -233 to -223°C ( -387 to -369°F), it’s debatable if ice is even slippery (although we’re so down with designing a wintertime frolic-rover to go test that out!). Snow is even weirder: the extreme cold would increase friction so much that skiing on it would be like skiing on a sandy beach.


Does Pluto have more moons to add to this artist’s concept of the family portrait? Image credit: NASA/ESA/M. Showalter/G. Bacon

We might find a new moon. Pluto has five confirmed moons. Charon is a massive bastard large enough to almost transform this into the Pluto-Charon binary dwarf planet system. Nix and Hydra are a pair of mid-sized moons where we’re having to estimate their sizes by assuming they’re just as shiny as Charon. The smallest of the group are the wee little Kerberos and Styx. The cluster is already weird enough with complex orbits we don’t fully understand (yet!), but the best bit is that we haven’t actually ruled out spotting more moons hiding amongst the orbits of the known moons. Taking a good look around for any stray satellites chillin’ around Pluto is part of New Horizons objectives over the next few days.


The downlink is 1.9 to 3.9 kbps. I didn’t typo that: the probe sends data back at 2,000 to 4,000 bits per second in the merest whisper of a signal from a 12-watt transmitter. The New Horizons probe will be sending home literally gigabytes of data on a connection that makes dialup look fast. This is why it will take approximately 16 months to transmit all this glorious data home. On the up side, the data is transmitted redundantly, preventing loss, and the spacecraft has enough juice to keep repeating the signal for a full decade if everything goes completely SNAFU.

Tomorrow, we’ll see Pluto in 3D. The second image on the downlink schedule tomorrow is a stereopair with the beautiful high-resolution view of Pluto released today. That means the two images were taken at the same distance, orientation, and resolution, but when the probe was at slightly different angles. The result means that if you unfocus your eyes like you would for a magic-eye puzzle, you can use the images to create a three-dimensional view of Pluto. This we can check out elevation differences, ogling crater rims, mountains, valleys, and chasms! Check out these stereopairs from Mars or of the Sun for examples.


The New Horizons team is way too good at using minimal data to extract accurate predictions: do not let them join your playoff pools. Image credit: ndromeda2803 from NASA/JHUAPL/SWRI data

Tomorrow, we’ll see Hydra for the first time. The only existing images of Hydra are just a few pixels. Yes, the New Horizons team are freaking badass rockstars at taking a tiny blurry image to create an impressively accurate artist concept to predict what worlds will look like, but the actual surface details of Hydra are going to be a complete surprise.

New Horizons has no moving parts. The spacecraft is designed like a giant thermos to trap heat, keeping it operating at room temperature. The only moving parts were a few protective instrument covers, all shed either in Earth orbit or after the Jupiter flyby. That means that the entire spacecraft needs to slew and tilt to look at anything. This also means that it can’t adjust to use part of itself to shield a camera from the sun, so we can’t take a new version of the Pale Blue Dot photograph made so famous by Voyager.


Ralph and Alice are TV references. The main colour camera on the probe, Ralph, is coupled with its ultraviolet spectrometer, Alice. The pair of instruments are named for the Kramdens in The Honeymooners TV show.

A colour-enhanced composite of Pluto and Charon. Image credit: NASA/APL/SwRI

Pluto has a broken heart. The now-iconic heart on Pluto looks like just one area to our eyes, but if you crank up the colours to emphasize compositional differences, it’s actually two distinct regions.


Being a dwarf planet isn’t a demotion. Pluto was reclassified as a dwarf planet because although it’s (mostly) spherical and in orbit around the sun, it doesn’t have the mass to clear out its orbit. But as of this week, it’s officially the largest dwarf planet at 2,370 kilometers (1,473 miles) diameter, +/- 20 kilometers. That makes it the undisputed King of the Kuiper Belt. More than that, in the words of SurferSquid:

Pluto wears its beard in man-braids, carries a battleaxe, and is handily available for tossing into a legion of orcs.

Dwarf planets.

They’re awesome.

And we’ve got a whole army of them camped out in the outer Solar System, protecting us from space orcs.


Being a dwarf planet doesn’t make Pluto anything less, and we can love it all the same.


New Horizons is an old sk00l hipster. The spacecraft codes are written in straight-up computer code, Assembly, not any of this new-fangled object-oriented user-friendly programming languages. Add in a 9-hour round-trip ping time and under 4kbps bandwidth and it’s downright impressive how quickly the team recovered the probe from its glitch over the holiday weekend. Update July 16, 2015: While some of the code is in Assembly, a NASA programmer dropped by to tell me they also use the much more human-friendly C, and that you should totally code for robots with them.

Even scientists place bets. The New Horizons probe launched nearly a decade ago. The mission scientists wrote down their guesses on what they thought they’d find, sealing them into an envelop entrusted to Principal Investigator Alan Stern. They’ll be opening up that envelop soon — we just hope they’ll share them with us!


Today was already historic. This is the 50th anniversary of the first image sent back from Mars. Then, the mission scientists were so impatient to see the first image by Mariner 4 that they hand-coloured incoming data in a research version of paint-by-numbers instead of waiting on the image processing team. That glued-together mosaic is still displayed on the walls at Jet Propulsion Laboratories. I love it when scientists surrender sleep in exchange for coffee and discovery!

Data delivery will slow down in August. We know specific data being collected by New Horizons will take abnormally long to download. NASA has scheduled sending home this data in August to give the New Horizons scientists a break after the intense mission ramp-up over the past few weeks (and the endless, eternal day today!)


Particles and Plasma lead Fran Bagenal exuberantly celebrates the resumption of communications with New Horizons on July 14, 2015. Image credit: NASA/Joel Kowsky

Pluto is probably brighter than you think it is. NASA released a tool where you can calculate your location’s “Pluto Time,” the time of day when the illumination is the same as noon on Pluto. I know the first time I tried it, I was shocked at how bright it was nearly 3.6 billion kilometers from the sun.


New Horizons is photographing by moonlight. The spacecraft is taking data both coming and going: even now the closest approach is past, the probe has swivelled around to keep taking photographs of Pluto illuminated by Charonshine, and Charon lit by the light of Plutoshine. The dimly-illuminated and crescents will allow the team to look for atmospheric haze, clouds, and any thermal structures on the night sides of the worlds.

These are the Pluto Kids. They were born on January 19, 2006: the day that New Horizons launched. Does sharing your birthday with the first spaceprobe to explore a dwarf planet make you awesomely geeky, or the most awesomely geeky?


New Horizons behaved perfectly during the flyby. The spacecraft checked in at exactly the second we anticipated, exactly where we wanted it, and filled up all the data slots we anticipated. Good spacecraft!

The probe got more capable after it was launched. The Alice ultraviolet camera was modified to also be a high-energy electron detector after the probe was launched. The instrument on New Horizons isn’t the only Alice system currently flying around the solar system — a twin aboard the Rosetta spacecraft was used to calibrate the detector.


New Horizons is fast. Pluto is very, very far away, so we had to hurl the spacecraft away from Earth with the most energetic launch ever performed. Even though it was already travelling at a scorching scorching speeds, we sent the probe on a velocity-boosting flyby of Jupiter to help it reach a truly staggering 14.52 km/s (9.02 mi/s). All this speed was so the probe would reach the dwarf planet in a reasonable amount of time, otherwise defined as, “Before we got bored and stopped funding the mission.”

Although this means that the probe was going way too fast to possibly go into orbit around Pluto using any currently technology, it’s still not the fasted artificial object in space. That honour belongs to the Voyager 1 and 2 probes, who are hightailing it out of the system at 17.46 km/s and 16.08 km/s respectively.

This doesn’t have to be the last Kuiper Belt flyby. Pluto is the first Kuiper Belt Object we’ve ever visited, but it doesn’t need to be the last. The New Horizons probe has enough juice in its nuclear reactor to keep on doing science for decade to come, and enough propellant to make a flyby with another Kuiper Belt Object. Two objects are on the short-list, but New Horizons needs funding approved by NASA for an extended mission. Want it to happen? Pester your congresscritter! After that, New Horizons will continue into deep space, taking an entirely different trajectory than the two Voyager probes as it reaches the outer edges of solar system.


New Horizons is in the constellation Sagittarius. You can wave to the space probe tonight by finding the archer. The constellation is visible in the summer months for North America.

Space is hard, but cheap. The entire New Horizons mission including development, spacecraft construction, launch, mission operations, data analysis, and public outreach cost only $700 million over 15 years. That’s 15¢ per American per year. The mission funding ends in 2016 unless an extended mission is approved and funded.


That’s it for us tonight! NASA TV will replay tonight’s streams for a while in case you missed it, and you better believe we’ll be back tomorrow afternoon with the latest images and science results. Thank you for joining us, and may your dreams be filled with dwarf planets and exploration.

We love you, New Horizons. Goodnight, Pluto. Goodnight, Charon. Goodnight, each and every little moon. We’re looking forward to the surprises you have to share with us!


Top image: New Horizons Mission Operations Center at John Hopkins University Applied Physics Laboratory hours before the expected arrival time of the first communication from the probe after the Pluto flyby on July 14, 2015. Credit: NASA/Bill Ingalls