Proof 1: - Our scale model of the New Horizons spacecraft is in the background, and you can compare here:

Proof 2: - c.f. Alan Stern’s Wiki Page:

Hello Reddit. We’re here to answer anything about Pluto and the spacecraft that will flyby Pluto next summer—NASA’s New Horizons. Its closest approach to Pluto will occur on July 14th, 2015, but encounter operations begin well before that, in mid-January!

We are:

• Dr. Alan Stern, Principal Investigator of New Horizons and postdoctoral researchers:

• Dr. Jason Cook

• Dr. Amanda Zangari

• Dr. Simon Porter

• Dr. Kelsi Singer

• Dr. Alex Parker

Why Is NASA doing this mission? Pluto and its large moon Charon are amazing binary planet system in a new region of the solar system called the Kuiper Belt, which is farther out than even Neptune—3 billion miles away. At the moment the best pictures we have of either from the Hubble Telescope only allow us to see fuzzy blobs of lighter and darker surface material. Humankind is about to get high-resolution pictures and many other kinds of data on Pluto for the first time thanks to New Horizons, and we want everyone to share in our journey of discovery!

Some good Pluto and New Horizons resources to read are:

• Why is Pluto so interesting?

• More about the spacecraft mission – and see a cool new video of Charon orbiting Pluto – taken by the spacecraft

• Countdown to Pluto Encounter!

• The current best maps of Pluto

EDIT: We have to head off to meetings to keep the spacecraft on track – but it has been great fun answering all of your questions. We will come back and update you closer to the flyby! Keep up with the discoveries at the websites below, Twitter - @NewHorizons2015, and Tumblr Postcards from Pluto by post-doc Amanda -

Comments: 1132 • Responses: 120  • Date: 

seattleandrew378 karma

What are your thoughts on the hit 90's movie, Space Jam?

NewHorizons_Pluto416 karma

Haven't seen it since the 90s to be honest, and I don't remember too much of what happened. I think we have it on VHS at my mom's house. Good soundtrack.


jc4466343 karma

How do you coordinate flight paths to objects billions of miles and avoid colliding with other objects on your way there?

How far apart are the objects within the Kuiper Belt?

NewHorizons_Pluto374 karma

Simon here. Guiding in space is a two-part problem. First, we need to know where all the objects are, and second is knowing where the spacecraft is. For the first problem we use telescope observations from Earth taken over a long time to see them move. For Pluto, we scanned in old-fashioned photographic plates of Pluto going back to its discovery in 1930. For the spacecraft, we use high-precision radio tracking from Earth, as well as optical navigation using the spacecraft's on-board telescope (LORRI).

NewHorizons_Pluto302 karma

Alex here. I did a quick calculation for you. Using the most up-to-date model of the Kuiper Belt (CFEPS L7), 50% of 100 km or larger Kuiper Belt Objects (KBOs) have another 100 km KBO within 1.3 AU (1.3 times the Earth-Sun separation) at any given time.

This, of course, neglects binary KBO systems. In one part of the Kuiper Belt (the Cold Classical Kuiper Belt), binary systems are extremely common - in fact, there may be more large KBOs locked in binary systems than there are solitary large KBOs.

powerscunner303 karma

How dark is it on Pluto? Would I be able to even see anything if I were standing on the surface?

NewHorizons_Pluto757 karma

When New Horizons reaches Pluto it will be about 33 AU from the sun (i.e. 1 Earth-Sun distance). The intensity of light falls off by the square of the distance from an object, so the sun on Pluto appears about 1/1000th (i.e. 1/332) the brightness on Earth.

1/1000 is about the difference between full sun at noon, and inside your house, which your eyes will have no trouble adjusting to.


Drunk-Scientist240 karma

What are New Horizon's post-Pluto travel plans? Have you found any nice Kuiper Belt Objects to visit?

Dariusplay1152 karma

That cyan colored bubble at 00:09, what is it? It seems it will hit the New Horizon.

NewHorizons_Pluto382 karma

That's Pluto! Don't worry, we'll miss it by 10,000 kilometers.


kaplanfx56 karma

Will any of those be close enough for LORRI to resolve them, or are we just going to see little points of light? I realize things like the spectrometer may produce interesting scientific data without resolution, but for us less scientific folks the photos will be the most intriguing data.

NewHorizons_Pluto58 karma

We've found many unreachable KBOs. These will be mostly points of light at closest approach, but we're trying to figure out what sort of science could be valuable, anyway.

Our spectrometers only work on bright objects.


NewHorizons_Pluto101 karma

We're looking for ancient KB objects to fly by, assuming NASA approves an extended mission after Pluto.

digiwinne212 karma

What instrument, developed since its launch in 2006, do you wish was on board New Horizons?

NewHorizons_Pluto264 karma

I talked to Alan about this question. It's not the answer you are looking for, because the most sorely-missed instruments were invented before the 2006. It's actually money that's the limiting factor.

The first instrument that we'd like to add is something that images in the far-infrared. This would have enabled us to get true thermal maps and detect sulfur.

The second instrument would be a cube sat that we would launch from the spacecraft. We could image the other side of Pluto. Or we could put a magnetometer aboard (we don't have one). Having the magnetometer be a separate thing inside the spacecraft would eliminate need to clean the craft (a pain).


Harshasunder204 karma

How long does it take for information to travel back and forth to the spacecraft now? When it is as far as voyager is now?

NewHorizons_Pluto320 karma

About 8.5 hours round trip, at the speed of light.

bassdude761 karma

Is that the time for a single bit of information? What is your data bandwidth? Any other communications details, like modulation type, etc?

NewHorizons_Pluto88 karma

About 1000 bits/second.


itsnotatoomer185 karma

Hello All! How many high res pictures do you expect to take during the flyby? If you had to guess, when do you think the first of the close high res pictures will be viewable by the public?

NewHorizons_Pluto366 karma

We'll be taking hundreds! And we plan to make them public as hey arrive, same day, each day, on approach!

auralvance146 karma

Considering the speed of NH, what percentage of Pluto/Charon will actually be visible during the brief flyby?

Footnote: Sooo immensely pumped for this. I watched the launch way back when in college and this feels like a whole piece of my life. Thank you for all the hard work and I can't wait to see the final results!

NewHorizons_Pluto157 karma

We'll get only one hemisphere at really high resolution. We will be imaging Pluto and Charon as it rotates in the days leading up to closest approach.

After flyby, to get some more of the surface, each day we'll be taking a few pictures where Pluto will be a crescent with about 15 degrees of the surface visible. -AZ

N4TEDOG109 karma

What's up good people! Exactly how far can a satellite (or other space exploration vehicle) travel before it's too far to send back pictures? How far does this mission plan to go? Thanks!

NewHorizons_Pluto180 karma

The answer depends on how good a radio system you have. In our case, we can communicate even farther out than Voyager is now.

manmeetvirdi93 karma

Which language is used for programming New Horizon's flight software?

How long is code?

How do you make sure that it's gonna work?

NewHorizons_Pluto150 karma

Okay, here's an answer from Helen Hart at Johns Hopkins University Applied Physics Lab (AZ):

  1. We do not program New Horizons flight software. We store commands, packaged into macros, in the portion of C&DH memory designated for command storage, and execute the macros via a Time Tag.

  2. See #1.

  3. How are we sure that it¹s gonna work? That¹s a really, really big question, involving multiple layers, multiple platforms, and a lengthy, intensive Load Build and Review process. For more details on the process, talk to the Science Sequencers.

The command load is simulated in SEQGEN, which is also where it gets built. The Seqgen Modeling File contains hundreds of checks for problems with commands vs. the state of the spacecraft/instrument. The Seqgen modeling file also contains the Mission Operations Playback Data Volume models.

We have a SOFTWARE SIMULATOR called stateSim which models the response of the spacecraft and payload to the command sequence. stateSim generates the file that Mission Operations Command Sequencer turns into the Command Sequence Timeline - the excel spreadsheet that is distributed as part of the load review process.

We have HARDWARE SIMULATORS, called NHOPS-1 and NHOPS-2, which contains HARDWARE modules for the onboard processors, including C&DH-1, C&DH-2, SSR-2, SSR-2, G&C-1, G&C-2, P-Alice, LORRI, PEPSSI, Ralph, REX-1, REX-2, SDC, and SWAP.

The NHOPS and stateSim simulators have different weaknesses; for example: a: NHOPS gets all the details of slews correct; stateSim gets the slew start time and duration correct, but does not track the exact path of the track because that part of the CG&C cannot be modeled in software. b: stateSim correctly predicts C&DH Thermal Control, but NHOPS does not predict this at all c: SSR usage: stateSim does not model SSR usage. NHOPS does, but gets the wrong answer for anything that gets Compressed or Packetized. SEQGEN is tied directly to commanded data downlinks, and cannot be manipulated to produce interim data volumes; it correctly models downlink data volume TO THE ACCURACY OF the Compression Ratios specified by the Science Sequencers (lately, DataTrack).

-- Helen

NewHorizons_Pluto80 karma

I emailed some folk, here's an answer to #3, from Jillian, one of the members of our SciOps team.

3: We have a program called Statesim that checks to make sure constraints are not violated. For instance the Alice aperture door shouldn't be open within 20 degrees of the Sun. We also have something called NHOps which is a software EM of New Horizons and the commands are executed on it and data is downloaded and reviewed by the instruments. We also had a rehearsal in 2013 for the Pluto Closest Approach load.


NH_SciOps80 karma

Hello Amanda!

NewHorizons_Pluto58 karma

upvoted. Ask your Sci-Ops questions here!


NewHorizons_Pluto46 karma

We don't do the coding for the flight software, that's SciOps.

However here's what I know, each set of spacecraft commands is put up as a "command load", which has a name that's the year plus the day of year. So the 15188 load runs on July 7, and has commands for nine days.

Each load has a multi week coding and vetting process and is simulated on the ground, on a system called "NHOPS", pronounced "nops".


skytracker83 karma

Pardon me for my impatience, but this is all so exciting! The question on the top of my list is, of course, when will we be able to see the first better-than-Hubble imagery of Pluto? I understand that, because of bandwidth considerations, data will take weeks and months to download, so when should we expect the “best” photos from the close encounter to be relased?

Will you be able to get a complete surface map of the planet, or are there parts that won't be visible because of the trajectory?

NewHorizons_Pluto126 karma

it is exciting! we will get the first better-than-hubble picture in mid-May! Some pictures will come down right away (day of and a few days after the encounter on July 14th) - and all will come back in a lossy format by mid-November :). Then we will get all of them back in a lossless format over the next year :).

Half of the planet will be in darkness, we will still try to get some pictures of it anyways :). ~Kelsi

liamsnorthstar13 karma

Can you set me up some sort of reminder? Do you have a New Horizons facebook page?

plqamz75 karma

Beside the pictures, what else do you plan to learn about the Pluto system?

NewHorizons_Pluto97 karma

Hello! We will also get tons of other information about composition of the surface, the atmosphere, and the interaction of Pluto with its space environment. There are a whole host of capable instruments on the spacecraft, each with a scientific goal.

PestilentMexican31 karma

Given the quick flyby new horizons will perform how will you perform all the critical measurements in such a short time? Several days if I'm not mistaken.

I am curious why performing at least one slingshot around Pluto was planned? This would give more time to follow up on any initial discoveries.

Sorry for typos, on my phone at the moment

NewHorizons_Pluto125 karma

We are taking all the pictures and measurements as fast as possible and saving them on two big solid-state drives. Then we'll slowly trickle them back over the next year and a half.

We are not doing a "slingshot" (technically a "gravity assist") around Pluto, because we are going so fast and Pluto's gravity isn't strong enough.

However, we able to get that fast by doing a gravity assist at Jupiter. Before Jupiter, we were just in an orbit around the Sun, but Jupiter's gravity put us on trajectory to leave the solar system entirely.


irishmcsg263 karma

Thanks for doing this! I'm curious about the paths that took you all to this project. Have you always been interested in Pluto? Did you come from other planetary research backgrounds? What was it that not only drew you to this mission, but also qualified and prepared you for it?

NewHorizons_Pluto100 karma

It's Alan, I was drawn to this because it's raw exploration, not the 10th mission to here or there, but first time, farther, faster, into the unknown. There's nothing else like it for me, I love it!

NewHorizons_Pluto66 karma

Alex here - I have a primarily astrophysics background, though my first published work was on Martian geology. My PhD work was on the small and numerous worlds of the Kuiper Belt, particularly those in binary systems.

As part of that research I developed some techniques for efficiently detecting extremely faint moving objects in digital images, and these techniques were needed for the search for a post-Pluto Kuiper Belt target for New Horizons. After completing my PhD I immediately joined the KBO target search effort as a postdoc, and have been working on that ever since.

NewHorizons_Pluto65 karma

Hello, this is Kelsi - I did my undergrad in astronomy, and my graduate work in planetary geology on the icy Moons of Jupiter and Saturn - so that is what set me up to work on Pluto - another icy body :). The skills you want are critical thinking, being able to write and communication (believe it or not ;) and working on your math and programming skills. I say working on, because you can always get better, but it helps to get a good start. :)

It is helpful if you can get involved in missions as a grad student or post-doc (work for an advisor who is on a mission) but if you get good at what you do - then people will want you on a mission :).

NewHorizons_Pluto65 karma

Amanda here- I did my undergrad at Wellesley College where I majored in Astrophysics and minored in math. I did my PhD at MIT in Planetary Science with Jim Elliot (discoverer of the Uranian rings) and later Rick Binzel, who is also a Co-I on the mission.

Working in Astronomy was a surprise to me. I got hooked on Astronomy at Wellesley, and just kept getting jobs.

As a grad student, I started this project where I cataloged the use of longitude and latitude for Pluto for every paper written since Charon's discovery in the late 70s. I guess that qualifies me.


NewHorizons_Pluto64 karma

Simon here. I caught the planetary bug in second grade, but I never thought I would be able to do it for a living until I got to do an internship at NASA JPL in Los Angles. After that, I worked in grad school (at ASU and Lowell Observatory) on the physics of Pluto and Kuiper Belts Objects, before I got be part of this mission earlier this year.

NewHorizons_Pluto63 karma

Last one here -- I got here through a lot of school, like everyone else. I knew I wanted to be an astronomer when I started high school. I attended Boston University for undergraduate school and got a BA in Astronomy & Physics (1995-99). While there, worked with Pluto and Triton data trying to detect carbon monoxide (CO) in their respective atmospheres. It was difficult data and we could only provide an upper limit. I knew then that I wanted to stick with Pluto. It was also at this time that Pluto missions were being approved and subsequently cancelled. From there, I went to Arizona State University for my PhD in Astrophysics (2007) and I focused on near-infrared spectra of Charon for my thesis. I also played with spectra and images of various comets .. but Charon was always calling. As I was within sight of finishing my degree (1.5 years away), New Horizons was nearing launch. I was lucky enough to present some of the work at the New Horizons launch science team meeting. And a year later, fate brought me to Colorado where I was lucky enough to land a post-doc position on New Horizons. That lasted two years, I then went to NASA Ames for bit before returning back to Colorado. So what brought me here? A bit of luck and a lot of drive. --Jason

phaseMonkey59 karma

What do you think will be the most significant find on Pluto?

What would you be shocked to find?

And is this your favorite scene from Spaceballs?

NewHorizons_Pluto79 karma

We will be shocked no matter what I think - it is impossible to predict what the most significant find will be - that is why we are going there! I think we would be really shocked though, if Pluto was very cratered, and Charon was not - we expect the opposite :). ~Kelsi

NewHorizons_Pluto64 karma

Yep, that's the best scene in the movie. John Hurt rocks.

  • Simon

NewHorizons_Pluto39 karma

:) ~Kelsi

AdamGoesTo1151 karma

This isn't a question about New Horizons but it does relate to the Kuiper Belt/outer zone of the solar system. I've heard that there's a statistical possibility that there could be more large planets the size of Mars or even Earth beyond the Kuiper Belt, but if they do exist, we don't have the technology to detect them.

How long do you think it will take before we have the technological capabilities to discover these possible objects?

NewHorizons_Pluto78 karma

There is an almost 100% chance more planets will be found farther out, but it's hard because our technology only lets us search a little ways out to the Oort Cloud so far. BIG new telescopes of the 2020s will do much better.

NewHorizons_Pluto56 karma

Alex here - there are interesting dynamical signatures in some of the populations of small worlds we know about in the outer solar system that suggest something is lurking further out. However, these signatures remain pretty ambiguous at present.

We do have strong limits on how big a planet can be at any given distance from the sun and still have evaded detection in our all-sky surveys (such as the WISE mission). Our technology is constantly improving - new instruments (like Hyper Suprime-Cam) are coming online all the time, and they all help open up new ways of searching for distant worlds in our solar system.

sabin35750 karma

Thanks for doing answering our various questions today guys. I think the others will have your mission specific questions covered.

What you think of video games like Kerbal Space Program that are getting so many people interested in rockets & space exploration? Have you played it or seen it played?

Related to that, what do you think of the resurgence of scientific space shows like Cosmos with Neil Degrasse Tyson?

NewHorizons_Pluto69 karma

I've never played KSP, but I have friends who love it. It sounds like a great way to get a feel for the actual physics involved. Movies hand-wave away so much physics that people don't really have a feel for what can't be done (i.e. sharp turns and fast breaking). I'll buy it eventually, but I have a very big Zelda backlog.

Cosmos is great. Humanity has gone from "what are these these stars that move against the background" and "this comet means we are all going to die" to flying by planets and landing on them like with Rosetta. It's super-important that the information we've learned actually gets out to as many people as possible, and Cosmos is a means to do that.


manmeetvirdi47 karma

Since this part of the Solar System is least photographed, what if spacecraft encounters a previously unknow body in its path? How to avoid collision? How much is the probability? You guys worried with any stuff of this kind?

NewHorizons_Pluto171 karma

To paraphrase Douglas Adams: "Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."

There's a lot of worlds in the Kuiper Belt, but the volume the Kuiper Belt occupies is absolutely HUGE. The risk of impacting a previously unknown object beyond the Pluto system is vanishingly small.

  • Alex

Ctschiering45 karma

What would happen upon arrival to the KBO if you started to receive photos of other spacecrafts or structures that look intelligently constructed on Pluto?

Serious question!

I only ask because I'm a sci-fi fan.

Thank you and I appreciate the hard work you guys are putting in to further mankind's journey.

NewHorizons_Pluto93 karma

Here's your serious answer.

Our minds would be blown, since Pluto's the absolute worst place for aliens to visit and stick stuff there. It's ... cold, hard to find unless you are looking for it, and Saturn's moons provide cooler views. We have rehearsed many scenarios, but this isn't among them.

There's not really we can do or change, because our imaging plan is locked and the flyby trajectory is set. Our last chance to change anything is at P-13, where we can choose a different (already written) sequence that uses the antenna as a shield to protect the spacecraft, or pick from a handful of pre-planned trajectories based on what we think is safest, but that's still really far out. By the time we are close enough to see images that unambiguously portray intelligent life, it will be much to late to do anything. When the best images come down, New Horizons will be past Pluto.

However, we will have no trouble getting a second mission to Pluto approved, if we did see aliens!


ramennoodle28 karma

However, we will have no trouble getting a second mission to Pluto approved, if we did see aliens!

Probably a quicker transit than 9 years, too! With a huge budget (along the lines of what one might expect if we found ET on Pluto), how long would it take to get back there? With deceleration for orbit or landing?

NewHorizons_Pluto56 karma

Nope, longer than 9 years. We get to go so fast precisely because we aren't slowing down.

Also, I don't remember where Jupiter is these days, but we'd another slingshot from it. Had we missed our launch window, years would have been added onto our travel time. I forget when it reopens.


MontyWeb40 karma

What do you hope to discover and how would it impact us?

NewHorizons_Pluto78 karma

We plan to make the first exploration of the Pluto system-- no mission has ever been there. In fact, no mission has been to a Kuiper Belt planet. We are exploring the unknown, the surprises nature present will be the most exciting parts!

harsh2005_721 karma

Voyager has been to kuiper belt isn't it?

NewHorizons_Pluto71 karma

When the Pioneers and Voyagers were launched, we didn't even know the Kuiper Belt existed. In fact, when Voyager 2 did its last planetary flyby in 1989, we still didn't know the Kuiper Belt existed! Plus, Voyager 1 went completely out of the plane of the Kuiper Belt (in order to fly past Titan).

Alex made up a plot of how close our four outer system predicessors went to known KBOs; not very close!


Prematin40 karma

  1. Is it possible to get a full map of Pluto, Charon and others with a flyby ?.
  2. Why a flyby instead of an insertion. NH had to travel a lot just to reach there. Can all the science missions be completed with in the flyby time ?

NewHorizons_Pluto77 karma

  1. We can't get a full map because it is not "equinox" on Pluto. Just like the south pole is completely shadowed in northern hemisphere summer, Pluto's south pole (determined by Pluto's rotation and the right hand rule) is permanently in shadow. We are going to try to image it using illumination from Charon. So we'll have one hemisphere at high resolution, and the other side at lower resolution.

  2. We get this question all the time, We don't have the fuel. Simon did a quick calculation, and it would take about 60x the mass of the spacecraft worth of fuel to stop it. Needless to say, we couldn't launch that.

Even though an orbiter can do a lot more than a lander, we've got the most sophisticated payload of any first-reconnaissance flyby spacecraft.


42-FTI38 karma

I remember the news about this mission being launched when I was just on grade school. Have there been any other discoveries since you launched New Horizons that has changed what you might have originally been looking for?

NewHorizons_Pluto75 karma

Yes: mooooooons. Months before launch, two new moons were discovered around Pluto (Nix and Hydra). In the years since, we have discovered two more (Kerberos and Styx). The Pluto system is absolutely lousy with moons.

  • Alex

TRLegacy36 karma

Did the discoveries of said moons made it necessary for you guys to calculate new trajectory of the probe because of gravity?

NewHorizons_Pluto23 karma

No need to remake the trajectory due to gravity. We did try to squeeze in some images of them though.


NewHorizons_Pluto32 karma

Yes! Just months before launch, two more moons of Pluto were discovered, Nix and Hydra. Several years after launch, moons Kerberos and Styx were discovered.

Since launch, Pluto's atmosphere has also been more extensively discovered via stellar occultation.


manmeetvirdi34 karma

Any plan to photograph Sun or Earth from Pluto?

NewHorizons_Pluto57 karma

No, we don't want to burn the cameras out on the Sun-- and the Earth in July is <1 deg away from Pluto, also too dangerous.


manmeetvirdi26 karma

Oh I thought Sun light is too faint out there to do any damage.

NewHorizons_Pluto82 karma

The cameras (Ralph and LORRI) are really sensitive, so that we can take pictures as fast as possible at Pluto. In fact they were almost blinded trying to look at Jupiter when we flew past in 2007.


MarsLumograph33 karma

Do you slow down when you get near Pluto or you fly by at the same speed (if I'm correct new horizons is the fastest spaceship ever).

Also, do you carry anything similar to the golden record that the voyager missions carry?

NewHorizons_Pluto60 karma

We don't have the speed to slow down much, and we don't want to, it would hurt the chances of flying a KB mission after. And besides, to really slow down we'd need a rocket the size of the one we launched with-- 227 feet tall!

willgrace32 karma

For the smaller moons (Nix, Hydra, etc), what will be the level of resolution / detail expected, and a coverage level?

NewHorizons_Pluto40 karma

At Nix we'll get images as good as on Pluto's global maps. For the others, not so well, since we have so little time and they all pass by the same day.

NewHorizons_Pluto37 karma

And we will be searching for new moons and rings on the way in to the Pluto system, both for science and to make absolute sure we don't hit anything.


CrazyDoode29 karma

Has your team identified any indication of the Pioneer Anomaly during the cruise phase and how do any non-gravimetric accelerations (including RTG Thermal Rebound) found compare to your models?

NewHorizons_Pluto51 karma

We haven't seen any non-gravitational forces on the spacecraft that can't be explained by known forces like the solar wind and RTG thermal emission. Part of that is that we have a much better thermal model of New Horizons than the faulty Pioneer 10 model that led people to think they saw the "Pioneer Anomaly".

UnknownVariation28 karma


NewHorizons_Pluto48 karma

Huge satisfaction that we did something good-- inspiring people, developing new knowledge, exploring!

robertsieg25 karma

A question for anyone: Is space exploration in the outer solar system dead? We had a golden age with the Voyager spacecraft, and a resurgence with Galileo and Cassini. But it seems that the majority of missions in recent years are focused on Mars. What's going on? And is there any hope for a change in direction?

NewHorizons_Pluto49 karma

Outer solar system exploration dead? Nope. There is the Juno mission which is currently on its way to Jupiter. JUICE, a European mission, is also going to Jupiter with a launch around 2022. Cassini is still going on until 2017. There are plans for a mission to Europa to examine the recently discovered plumes. And there are proposed missions to get back to Titan. Depending on where you draw the lines for the outer solar system, Dawn will reach Ceres in April 2015 and Rosetta is orbiting Comet 67P/Churyumov-Gerasimenko .. and comets tell us a lot about the outer solar system and the environment it formed in.

Yes there is a lot of focus on Mars, but that is all for good reason. Mars is close. When a mission takes 9 years to get to its target (compared with several months or 1 year to get to Mars), a lot of things can go wrong. And because Mars is relatively easy to get to, we can learn a lot about the solar system in general, the likelihood of forming life, and what made Mars so different from Earth.

Mars will probably be an object of interest for some time. But so will Europa, Titan and Enceladus. --Jason

itisp25 karma

On you have a lot of imagery and factoids about Triton which, unlike the other subjects mentioned, has nothing to do with the NH mission. Is it because Triton is the best Pluto analogue we have a reasonable amount of data about? If so, how similar would you expect Pluto to be to Triton?

NewHorizons_Pluto33 karma

Hello! This is post-doc #4 - I can answer your question as I worked on Icy Satellites for my dissertation work. You are correct that we think Triton might be one of the best analogues to Pluto and that is why we feature it on the website :). Triton does not have very many craters, and that is because other geologic landforms have resurfaced it, including possible cryovolcanic features, funky terrain called "cantaloupe terrain" and tectonics. :) Pluto probably won't look exactly like that, but it we think it probably doesn't have a ton of craters (as in, it will not look like the Moon!)

richardtheb25 karma

We've seen a surprising number of rings around planets, with small ones around Jupiter and Neptune. Any sign of one or more around Pluto?

(Pluto will be a planet until they pry my telescope from my cold, dead hands)

NewHorizons_Pluto22 karma

Ground-based occultation data say no, but we will look anyway!


MaryKayCarson25 karma

Is Pluto and Charon considered a double planet system?

NewHorizons_Pluto42 karma

Yes! Pluto isn't much bigger than Charon, and their common centre-of-mass is about a Pluto radius above Pluto's surface. So, New Horizons doesn't see just Charon orbiting around Pluto, but also Pluto wobbling back and forth as Charon pulls it around. Charon is actually bigger all of the main belt asteroids, including the dwarf planet Ceres. Plus, there are least 4 more small moons that orbit around Pluto-Charon; it's like a miniature circumbinary solar system.

  • Simon

curltest24 karma

What's on the team's list of must-watch space and/or engineering and/or science movies..?

NewHorizons_Pluto65 karma

2001: A Space Odyssey, Apollo 13, Gravity, Silent Running, Her, Moon, can't wait for Interstellar!

Ye_Olde_Asshole23 karma

What's it like working on a mission with such long times and great distances. Exciting? Challenging? Nerve wracking?

NewHorizons_Pluto37 karma

It's a challenge we love! Truly! -Alan

Dopeaz23 karma

You've got me excited about the "fly-by" aspect of this. Will you be following Voyager's footsteps and make passes by the other planets/objects on the way? (Or at least closer hi-res pictures?)

What's the camera like on that sucker? Got a telephoto lens? Power?

How is the speed of NH in relation to ye olde Voyager? Any chance it's going much faster and will pass Voyager? Can it relay communications from Voyager?

I may have a crush on Voyager. How has the tech improved in relation to the communication systems between the two? Still slow radio or do you have some awesome laser coms? Any chance I could call Yoyager and tell it I love it?

Why should I love New Horizons more? Is it single?

NewHorizons_Pluto37 karma

Alex here - New Horizons has a few cameras, but it does have one pretty serious telephoto: LORRI, the Long Range Reconnaissance Imager. It is a 208mm-aperture telescope with a 2630 mm focal length. This is one of my favorite instruments because of what it can get us as New Horizons continues on into the Kuiper Belt.

NewHorizons_Pluto28 karma

Yes, Love New Horizons more. And yes, it's single!

NewHorizons_Pluto28 karma

Simon here. New Horizons is going slower than both of the Voyagers, because they had two and four giant planet flybys, respectively, while New Horizons only had one. That means the New Horizons will never pass them. However, New Horizons is a much smaller spacecraft and was launched on on rocket that was only a bit less powerful than the Titan-Centaur that launched the Voyagers. So, New Horizons was the fastest powered spacecraft ever when the Atlas V launched it in 2006.

For comparison, missions to Jupiter that intend to stay there (like Galileo and Juno) take many years to slowly reach Jupiter and softly go into orbit. We screeched through the inner solar system and reached Jupiter in a year. NH is a speed demon!

justforthelulzz21 karma

Budgets aside, what mission would you like to be done in the future that involve spacecraft like New Horizons?

NewHorizons_Pluto38 karma

If I were king, I'd love to see more New Horizons mission using Uranus and Neptune flybys to go on to other planets in the Kuiper Belt, like MakeMake, Eris, and Orcus. -Alan

Slothnazi21 karma

What is the average age for the crew participating in this mission?

NewHorizons_Pluto55 karma

Not sure across the whole mission, but in this room the arithmetic mean age is 30.

Mini_Elon19 karma

What is the biggest challenge in getting New Horizons to Pluto?

NewHorizons_Pluto53 karma

Alan says the competition for getting funding.


jstrydor19 karma

What are some interesting things that you can tell us about Pluto that we probably don't know?

NewHorizons_Pluto33 karma

From ground based observations, we know that its surface is covered in nitrogen (N2), methane (CH4) and carbon monoxide (CO). There are also traces of (at least) ethane (C2H6) with predictions of other hydrocarbons and possibly nitriles (e.g., HCN, hydrogen cyanide). One thing we haven't seen on Pluto's surface is water ice (H2O). Pluto's near-twin, Triton, does have detectable water ice. The difference might have to do with how ices/frosts migrate over different seasons on each of the objects. I should also add some perspective here .. our detection of these ices is done at near-infrared wavelengths (generally 1.0-2.5 microns) and that only measures the top millimeter of ice or so. So it would not take much to bury water ice. New Horizons may find small, isolated patches of water ice during its flyby. This is, of course, one of many things we don't know that I (Jason) personally will find interesting.

Papaburgundy1917 karma

Just talked about this in my geology class at my college and got very interested in this mission so it's pretty awesome to see this. Anyway, how long will it take to transmit data from Pluto to Earth? And what do you hope to find there?

NewHorizons_Pluto29 karma

The time it takes for a signal to get from one end to the other is about 4 hours. BUT, the rate at which the full resolution images are returned is slow. We won't have all of the data from the flyby down until October 2016. This will sort of make the flyby feel more like an orbiter, because we will be releasing new discoveries for months after July 2015.

I personally hope we find that Pluto and Charon are not dead frozen worlds, but ones like Triton and Enceladus with plumes and geysers. --Jason

oninonin17 karma

Hello, and thank you for doing this AMA! Been following the team on twitter for a while and I'm so existed for next year Pluto flyby! My question is, how long is New Horizon going to work after the Pluto Flyby, can we expect some more data and photos coming way past the Kuiper Belt? I remember the last photo send from Voyager 1, and I cannot even imagine what king of pictures could NH send from there!

NewHorizons_Pluto23 karma

New Horizons should remain alive until late 2030s.

I am not aware of what kind of data it will return past the Kuiper belt. But I can imagine the SDC (Student Dust Counter) will remain in operations. If we happen to get a chance KBO within range (1 AU?) maybe we'd get a few images of it, but it wouldn't be anything like the Pluto images. It would be a pixel or two.

There are images planned that will be specifically for the Kodak moment. You'll have to wait and see what they are.


NewHorizons_Pluto51 karma

In my headcanon, a self-aware N'zons returns to Earth alive and well in the 2270s.

Tr0user17 karma

Was Gravity realistic?

NewHorizons_Pluto42 karma

Some ways yes, some ways no. It sure was beautiful eye candy though!

AdamGoesTo1116 karma

How long before New Horizons arrives do you expect to start seeing any new moons? I know you guys saw Hydra last month where the spacecraft was. When do you think you'll be able to start finding new ones beyond the known 5?

NewHorizons_Pluto26 karma

Encounter begin in January, but we will not have imagery able to detect new moons until late spring when we're closer. That's bcs Hubble has done such a great job so far.


patinam16 karma

Apart from budget, was there any reason you choose to target only one planet instead of manoeuvring from one to another like Voyager?

NewHorizons_Pluto32 karma

Alex here - astrodynamics is a buzzkill. Humanity got very lucky with the timing of the Voyager missions, given an arrangement of the planets that made for that sequence of encounters practical. New Horizons used a Jupiter flyby to boost its speed and make the cross-solar system cruise relatively short (~9 years), but trying to target other outer planets in a grand tour-style mission would be extremely hard given the current arrangement of the planets.

lockd0wn16 karma

Why focus on Pluto instead of another planet?

NewHorizons_Pluto54 karma

We've already sent spacecraft to Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune, some multiple times. This will be our first and possibly only visit to Pluto.


omega2four11 karma

Thanks for your time!

  • At what range is your closest approach to Pluto?

  • What type of resolution can we expect from the imagers?

  • As a meteorologist, I'm quite interested in what type of atmosphere you think Pluto is capable of holding. What are your expectations there? Thickness, composition, etc. What type of measurements will you be able to take? I'd imagine if you know the mass, thickness and composition you can figure out a surface pressure. Will you be attempting this? Any first guesses? How about surface wind speeds?

NewHorizons_Pluto17 karma

hello! the resolutions for the some of the best images will be ~70 m/pixel, great for looking at high resolution of the surface.

The range at closest approach is 10,000 km, or 6,200 miles, and it will be traveling at 14 km/s (31,300 miles per hour!) ~Kelsi

cbellh4710 karma

If Pluto has a ring system, when during the approach would you expect to see it?

Charles Bell

NewHorizons_Pluto28 karma

Hi Charles,

We are going to try to look for hazards and unseen moons as often as we can to avoid any collisions with an unseeable ring system. Our last chances to do see rings and do something about it to adjust our trajectory are at P-13 days and P-18 days.

However, after the Pluto encounter is the best time to see rings. Think of how when driving into the sun you can see all the dirt on your windshield. So after it's on the other side of Pluto, New Horizons will point back to look for unseen objects. Voyager discovered Jupiter's rings this same way.


zdognzl10 karma

The real question, Star Wars or Star Trek?

NewHorizons_Pluto27 karma

Doctor Who

NewHorizons_Pluto28 karma

What? Battlestar Galactica.

NewHorizons_Pluto27 karma

Please. Space: 1999.

NewHorizons_Pluto39 karma

I can't believe I'm sitting in the same room as y'all.

NewHorizons_Pluto26 karma

Doctor Who -- Jason

NewHorizons_Pluto20 karma

Star Wars -AZ

LTRoxas9 karma

New Horizons will orbit Charon and is going to study it?

NewHorizons_Pluto21 karma

We can not orbit Pluto or Charon with this mission (maybe in the future?). This is simply a flyby, much like the Voyager missions. But this doesn't mean we are not going to study Charon. There will be plenty of observations of Charon, including imaging, spectra and a search for an (extremely thin) atmosphere. --Jason

KevinUxbridge9 karma

No fuel to brake?

NewHorizons_Pluto27 karma

Everyone asks us that so Simon did a back of the envelope calculation. At 14 km/s, it would take 60 times the spacecraft's weight in fuel to stop it. Given that getting to Pluto in 9.5 years relied completely on the craft being so light.


robertsieg7 karma

For Alan: I believe you recently challenged Neil Degrasse Tyson to a debate on the planet status of Pluto. Any response? :)

NewHorizons_Pluto11 karma

Alan tells me Neil declined to participate.


DontLickMyAssHole4 karma

What are you expecting to find next July? What's the biggest break through you're hoping to find?

NewHorizons_Pluto7 karma

We don't know, that's the nature of raw exploration. The best part will be the surprises!

Stumpledumpus4 karma

Thanks for doing this! In your opinion, what is the most important piece of information New Horizons will learn about Pluto?

NewHorizons_Pluto9 karma

Not one piece of info, but the whole story of what Pluto and moons are about! Images, spectra, thermal maps, atmospheric samples, escape rate measurements, mass, searches fr new moons and rings, color maps, composition maps, and more-- who knows what will be most important? It's exploration!

_aex4 karma

What's the biggest misconception about spacecraft you'd like to clear up?

Also, what's the best thing about working at NASA?

NewHorizons_Pluto8 karma

answer to #1 - the spacecraft is not an orbiter and not a lander! ;) it is a very very cool flyby mission, which means we will get to hopefully see other objects as we keep flying! ~Kelsi

samibal4 karma

Will the New Horizon's Pluto approach be covered on NASA TV? And when exactly will the spacecraft reach Pluto? And do you think that Pluto will regain its planetary status?

NewHorizons_Pluto12 karma

Yes, lots of NASA TV planned, other coverage too! Watch in July-- closest approach is Bastille Day-- 14 July- we'll be storming the gates of Pluto!

manmeetvirdi4 karma

How will you know that you have reached Kuiper Belt?

NewHorizons_Pluto9 karma

Alex here - New Horizons entered trans-Neptunian space in August 2014 when it passed the orbit of Neptune, so I would argue that we're in the Kuiper Belt right now. In fact, a full year ago New Horizons passed within 1.2 AU of a Neptune Trojan that our KBO survey team discovered (2011 HM102).

KerbalPlayer3 karma

Not sure if this will get answered, much less if it's even a good question, but does it pain you to see all the new technology that has arisen since New Horizons was launched? Technology that would have been perfect for the mission if it had been around? When it arrives at Pluto, it will be a decade out of date, it doesn't even know what an iPhone, (Advanced) Multi-Core Processors, or Twitter is. (I'm using "It" as a pronoun for the spacecraft)

NewHorizons_Pluto5 karma

The spacecraft is not a person. Since we know what twitter, you can follow Alan as NewHorizons2015. Even Voyager has a twitter, and your TI-84 has more computing power. We wouldn't want to send an iphone to run New Horizons-- they're much too fragile. Space hardware works differently.

I would say our biggest limiting factor is our data downlink rate, which new technology really wouldn't fix.


TheSwarre3 karma

How much do you care for this project? is it a baby of yours?

NewHorizons_Pluto3 karma

We care a great deal-- it's a great honor and a privilege to be able to explore for humankind this way. And in a real sense, New Horizons is our baby!

assburp3 karma

What is/are your preferred brands of toilet paper?

NewHorizons_Pluto8 karma

trader joes

two_off3 karma

What are all of your roles at NASA, and what will be the most interesting aspect of the mission on a personal level?

NewHorizons_Pluto5 karma

We all work on various aspects of making sure the mission is successful, including planning of the encounter and observations, and avoiding hazards that we discover along the way. We also do science, either making predictions or working on the data that comes back :). Good question about the personal level - for me it is hard to imagine anything more exciting than going to a planet for the first time! Everyone will get to experience that with us :). ~Kelsi

Universu2 karma

How was the New Horizons mission formulated? When did it officially started and how long will it last?

NewHorizons_Pluto4 karma

Formulated in 2001-2002. Approved for build 2003. We hope it will last into the 2020s or longer, but that depends on NASA approval for extended mission(s).

Omega5002 karma

Has it got one of those gold disc's on board?, and if so where can i get some details. Am curious how much its changed from the Voyager crafts.

NewHorizons_Pluto6 karma

No. We have 9 "stowaways", let's see if I can remember what they are:

  1. (some of) Clyde Tombaugh's ashes
  2. A Maryland state quarter
  3. A Florida state quarter
  4. A US flag.
  5. A piece of spaceship one
  6. A CD-Rom with the names of people who submitted their names to NASA before launch.
  7. Another US Flag
  8. Another CD with pictures of New Horizons personnel (so no pictures of me, as I was hired a little over a year ago).
  9. The 1991 "Pluto- not yet explored" US stamp.

More here-

There is a campaign to fill the hard drive with more names after the data come down and the mission is over.


RizzMustbolt2 karma

So what are you guys doing in the ten month wait until New Horizons wakes up again?

NewHorizons_Pluto6 karma

We're doing a lot of design and software coding for the flyby. We're also building software tools to analyze the data . And we're reaching out to excite people with public events to get the word out!

jerryk4142 karma

Who are your favorite super heroes?

NewHorizons_Pluto6 karma


BasilHaydens2 karma

Do you ever use Kerbal Space Program to help simulate missions?

NewHorizons_Pluto5 karma

No, but I have friends begging me to download the game because it's fun.


justking2 karma

How did it feel to launch New Horizons in 2006 to flyby the planet Pluto only for Pluto to be downsized to a dwarf planet 7 months later?

NewHorizons_Pluto4 karma

Not great. We feel we're doing something magical, important, historic. Downgrading hurts all the people who put their lives into this. But we go on.

Mini_Elon2 karma

Do you expect interstellar dust to be a problem with the spacecraft when it nears Pluto?

NewHorizons_Pluto6 karma

No, but we are studying it with the Venetia Burney Student Dust Counter!


manmeetvirdi2 karma

How does you make sure that commands being uploaded has reached spacecraft in its full integrity? What I meant is no loss of zero's and one's ;)

NewHorizons_Pluto5 karma

On both the ground and the spacecraft we have checksums built.

luckytran2 karma

What are the primary science objectives you hope to uncover from the Pluto encounter? How much will we be able to learn about the internal structure and origins of Pluto, and what data will help us do that?

NewHorizons_Pluto6 karma

Every mission has a ranked list of science goals. Our biggest ones are to take pictures so we know what Pluto looks like (i.e. maps) and what it's made of. Lower on the list is to find additional moons.

The technical version of our science objectives can be found here (scroll to page 6 and 7):


digiwinne2 karma

What do you dream of finding at Pluto and Charon? Something in the atmosphere? Water ice?

NewHorizons_Pluto3 karma

Something wonderful! We want to know everything and have the most powerful payload ever brought to bear on a first recon of a new planet. We don't know what we'll find!

Mini_Elon2 karma

What is the mission of New Horizon after it main mission is over?

NewHorizons_Pluto4 karma

If NASA approves, we'll fly on to study ancient Kuiper Belt Objects as the National Academy of Science request of this mission.

Chickstick1992 karma

What are the results of Hubble searching for KBOs ? Is the search already over? When will possible candidates be announced?

NewHorizons_Pluto4 karma

The results are TBD - because the search and characterization of Kuiper Belt targets is not yet over, we don't know yet when an announcement can be made.

Timbotron2 karma

  1. Are you guys jealous that the Dawn team will be the first to explore a minor planet?

  2. What is your most optimistic guess for a Pluto mission after New Horizons? We'll get a pretty good look at it next year, but that'll be just a snapshot of it at one point in its orbit. Do you have specific wishes for studying what changes during other seasons?

  3. What do you think could be done to boost public interest in space exploration? The Curiosity landing was an extremely popular event but the more recent MAVEN and MOM got a lot less attention. Another interesting example is Japan's Hayabusa mission which got a ton of attention back home, had model kits produced and even a 2+ hour drama film starring Ken Watanabe. Is it getting harder in the west to get people excited about something happening millions of of miles away?

NewHorizons_Pluto3 karma

Dawn is an awesome mission and we can;t wait for them to reveal Ceres!

manmeetvirdi2 karma

Does Pluto has seasons?

NewHorizons_Pluto4 karma


On Earth, axial tilt is the reason for the season, and Pluto's got some pretty extreme axial tilt.

Unlike Earth, which has a pretty circular orbit (fun fact: Earth is closet to the sun in January), Pluto's distance from the from the sun changes drastically, so both axial tilt and solar distance come into play.

In the late 1980s, Pluto was edge-on as seen from Earth, AND was at perihelion (closest to the sun). Now, Pluto's northern hemisphere is in sunlight and its southern hemisphere will be in shadow until 2113 or so (because Pluto is tipped over on its side, there's actually quite the controversy about which side is north-- you can read more about it here:

Pluto hasn't even been around the sun once, so we're still trying to learn what seasonal changes can be seen, and many scientists have made models. In particular, Candy Hansen and Leslie Young have made models, some of which predict atmospheric collapse will happen when Pluto gets too far from the sun. From stellar occultations (Pluto passes in front of a star and the atmosphere refracts its light), we know the atmosphere doubled in pressure from 1988 to 2002. We don't have any reliable Pluto) occultation measurements before '88 (there was an unreliable one in '85), but teams from SwRI, MIT and France have been measuring Pluto's atmosphere as often as they can. Recent results show the atmospheric collapse is less likely.


Moradia1 karma

How does it feel driving a spacecraft? Like driving a car or watching some sci-fi movie?

NewHorizons_Pluto1 karma

I don't do any of the 'flying' myself, but my impression is that it feels mostly like bursts of this followed by lots of waiting.

shannonator961 karma

Does the fact that we're exploring Pluto mean it's a planet again? Because I'm sick of calling it 134340

NewHorizons_Pluto3 karma

We are too! In fact, we don't bother It's Pluto.

DynastyFTW1 karma

How long will the spacecraft be at pluto?

NewHorizons_Pluto3 karma

The best stuff will happen on closest approach day, July 14, 2015 (Bastille Day). However, we'll be doing Pluto science from April to July.


NewHorizons_Pluto2 karma

6 months, January to July.

TyneSkipper1 karma

Hi Guys.

can I ask how long the Pluto flyby will take?

NewHorizons_Pluto3 karma

6 months, January to July.

Van_Gundy1 karma

Do you think that Pluto should be re-included as a planet?

NewHorizons_Pluto4 karma

Sure do. In fact, to many, many planetary scientist, the IAU definition is just &%$ scientifically, we've always considered it a planet.

NewHorizons_Pluto1 karma

Isn't it already?

Chickstick1990 karma

Why should Pluto be classified as a planet again? Except for it being the first KBO to be discovered (and New Horizons visiting), it doesn't seem to fit in well:

  • It has a highly eccentric orbit , with its perihel being under Neptunes perihel
  • Its orbital plane is at ~17° , far more than what our 8 planets have
  • It needs to have “cleared the neighborhood” of its orbit (This I personally find a little silly, but it's what the IAU says)
  • There are many other KBOs in our solar system (with Eris being larger than Pluto), so shouldn't many of those then be classified as planets aswell? It would seem to me that this would lead to a ridiculous amount of planets, especially with many more KBOs waiting to be discovered.

I understand that many Pluto enthusiasts have embosomed the former planet into their hearts, and are infuriated by the IAUs decision, but I don't think it's fair.

So tell me: What are your arguments in "favor" of Pluto?

Edit: Formatting

NewHorizons_Pluto2 karma

Pluto is a planet for a simple reason" It is big enough for gravity to overwhelm material strength and round it into a sphere. That's tthe basis of planethood.