Artist's conception of the Pluto system from the surface of one of its moons. Credit: NASA, ESA and G. Bacon (STScI)
When you have a spacecraft that takes the better part of a decade to get to its destination, it’s really, really important to make sure you have an accurate fix on where it’s supposed to be. That’s true of the Rosetta spacecraft (which reached its comet today) and also for New Horizons, which will make a flyby past Pluto in 2015.
To make sure New Horizons doesn’t miss its big date, astronomers are using the Atacama Large Millimeter/submillimeter Array (ALMA) to figure out its location and orbit around the Sun. You’d think that we’d know where Pluto is after decades of observations, but because it’s so far away we’ve only tracked it through one-third of its 248-year orbit.
“With these limited observational data, our knowledge of Pluto’s position could be wrong by several thousand kilometers, which compromises our ability to calculate efficient targeting maneuvers for the New Horizons spacecraft,” stated Hal Weaver, a New Horizons project scientist at Johns Hopkins University Applied Physics Laboratory in Maryland.
Pluto’s moon Charon moves around the dwarf planet in this animated image based on the data from the Atacama Large Millimeter/submillimeter Array (ALMA). Credit: B. Saxton (NRAO/AUI/NSF)
As ALMA is a radio/submillimeter telescope, the array picked up Pluto and its largest moon, Charon, by looking at the radio emission from their surfaces. They examined the objects in November 2013, in April 2014 and twice in July. More observations are expected in October.
“By taking multiple observations at different dates, we allow Earth to move along its orbit, offering different vantage points in relation to the Sun,” stated Ed Fomalont, an astronomer with the National Radio Astronomy Observatory who is assigned to ALMA’s operations support facility in Chile. “Astronomers can then better determine Pluto’s distance and orbit.”
New Horizons will reach Pluto in July 2015, and Universe Today is planning a series of articles about the dwarf planet. We’ll need your support to get it done, though. Check out the details here.
A NASA "poster" marking the one year to Pluto encounter by New Horizons. Credit: NASA
Countdown! Just under one year from now, the New Horizons will finally reach its mission goal after sailing through the solar system for the better part of a decade. It will fly by the dwarf planet Pluto and its moons on July 14, 2015, showing us the surface of these distant bodies for the very first time.
And the New Horizon’s team reported a thruster burn yesterday has put the spacecraft right on course to correct the spacecraft’s arrival time – a year from now – at the precisely intended aim point at Pluto.
The spacecraft fired its thrusters for just under 88 seconds, which sped the craft up by about 3.8 km/h (2.4 miles per hour.)
“If we hadn’t performed this maneuver, we would have arrived at Pluto about 36 minutes later than we wanted to,” said Mark Holdridge, New Horizons encounter mission manager. “Making the adjustment now means we won’t have to perform a bigger maneuver – and use more of the spacecraft’s fuel – down the road.”
“It was a great burn, performed flawlessly” said Alan Stern, New Horizons principal investigator. “You could say that New Horizons just lit a little candle for its one year out anniversary.”
It was the spacecraft’s sixth course correction maneuver since launch in January 2006, and the first since 2010.
“Pluto gets closer by the day, and New Horizons continues into rare territory, as just the fifth probe to traverse interplanetary space so far from the sun,” said NASA on the New Horizon’s website. “And the first ever to travel to Pluto.”
It’ll be a treat to see what the dwarf planet looks like after so many tantalizing glimpses by the Hubble Space Telescope and New Horizons spacecraft itself (see this story from last week for some views.) Happy sailing!
Pluto’s surface as viewed from the Hubble Space Telescope in several pictures taken in 2002 and 2003. Though the telescope is a powerful tool, the dwarf planet is so small that it is difficult to resolve its surface. Astronomers noted a bright spot (180 degrees) with an unusual abundance of carbon monoxide frost. Credit: NASA
Artist's impression of the New Horizons spacecraft. Image Credit: NASA
After almost nine years on the road, New Horizons is in what NASA calls “Pluto-space”! Earlier today (July 7), the spacecraft Twitter account announced New Horizons is now 29.8 Earth-sun distances (astronomical units) away from the Sun, putting it within the boundaries of Pluto’s eccentric orbit — exciting, since Pluto is the primary science target.
“Didn’t get the word? We’re farther out than Pluto’s minimum distance to the Sun. We’re in ‘Pluto-space’ now!” tweeted the New Horizons account. We’ve included some of the best Pluto pictures below, to date, to celebrate.
And while many are focused on the Pluto encounter itself, NASA is already planning for what to do next for the spacecraft. In mid-June, we reported that the Hubble Space Telescope was doing a test search for icy Kuiper Belt objects that New Horizons could possibly fly to next.
That test search was successful enough, with two objects found, that Hubble is now doing a full-blown investigation, according to an announcement last week. Hubble will begin that work in July and conclude observations in August. New Horizons is expected to fly by Pluto and its moons in July 2015.
Pluto’s surface as viewed from the Hubble Space Telescope in several pictures taken in 2002 and 2003. Though the telescope is a powerful tool, the dwarf planet is so small that it is difficult to resolve its surface. Astronomers noted a bright spot (180 degrees) with an unusual abundance of carbon monoxide frost. Credit: NASAPluto and its moons, most of which were discovered while New Horizons was in development and en route. Charon was found in 1978, Nix and Hydra in 2005, Kerberos in 2011 and Styx in 2012. The New Horizons mission launched in 2006. Picture taken by the Hubble Space Telescope. Credit: NASAPluto and moons Charon, Hydra and Nix (left) compared to the dwarf planet Eris and its moon Dysnomia (right). This picture was taken before Kerberos and Styx were discovered in 2011 and 2012, respectively. Credit: International Astronomical UnionPluto appears as a faint white dot (see arrow) in this image taken by New Horizons in September 2006, nine months after launch. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research InstitutePluto and Charon are visible in this 2013 image from New Horizons’ LOng Range Reconnaissance Imager (LORRI). It was the first image from the spacecraft showing Charon separated from Pluto. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Artist's impression of New Horizons' encounter with Pluto and Charon. Credit: NASA/Thierry Lombry
It’s going to be a really busy summer for the New Horizons team. While they’re checking out the newly awakened spacecraft to make sure it’s working properly for its close encounter with Pluto next year, NASA is already thinking about where to put it next: possibly towards a Kuiper Belt Object!
So now the Hubble Space Telescope (in Earth orbit) is scoping out icy objects beyond Pluto. Luckily for us, one of the team members — Alex Parker, a planetary astronomer at the University of California, Berkeley, provided an entertaining livetweet of the process — even through a power failure.
So, the secret is out. On Friday, we were awarded the Hubble time to search for a @NewHorizons2015 KBO target!
There’s far more to Parker’s tweets than we are indicating here; his Twitter feed also has details about the collaborators, for example, so be sure to read through the entire exchange from yesterday. The survey is led by the Southwest Research Institute’s John Spencer.
What astronomers are doing now is a “pilot observation” where the space telescope looks at a spot in the constellation Sagittarius. Controllers will try to turn the telescope at the same rate as what a KBO would be orbiting around the sun. If the method works, stars will look like streaks and the KBOs will look like “pinpoint objects”, NASA stated.
A view of the Hubble Space Telescope from inside space shuttle Atlantis on mission STS-125 in 2009. Credit: NASA
“If the test observation identifies at least two KBOs of a specified brightness it will demonstrate statistically that Hubble has a chance of finding an appropriate KBO for New Horizons to visit. At that point, an additional allotment of observing time will continue the search across a field of view roughly the angular size of the full moon,” NASA said in a press release.
The reason for this step is Hubble is a high-profile telescope, receiving a lot of requests for observing time around the world. The agency wants to ensure that the telescope is being used for the best scientific return possible. NASA also noted the search might be difficult.
“Though Hubble is powerful enough to see galaxies near the horizon of the universe, finding a KBO is a challenging needle-in-haystack search. A typical KBO along the New Horizons trajectory may be no larger than Manhattan Island and as black as charcoal,” NASA stated.
This isn’t the first time the telescope has done a pinch-hit for Plutonian science. Four new moons have been found around Pluto, a discovery that involved Hubble time. The telescope has also looked for dust rings near the dwarf planet (to do a risk analysis for New Horizons’ approach) and done a map of the surface, to help controllers figure out where to target New Horizons.
Artist's impression of the New Horizons spacecraft. Image Credit: NASA
While many kids in the U.S. are starting their school summer vacations, New Horizons is about to get back to work! Speeding along on its way to Pluto the spacecraft has just woken up from hibernation, a nap it began five months (and 100 million miles) ago.
The next time New Horizons awakens from hibernation in December, it will be beginning its actual and long-awaited encounter with Pluto! But first the spacecraft and its team have a busy and exciting summer ahead.
New Horizons tweeted about its Father’s Day wakeup call
After an in-depth checkout of its onboard systems and instruments, the New Horizons team will “track the spacecraft to refine its orbit, do a host of instrument calibrations needed before encounter, carry out a small but important course correction, and gather some cruise science,” according to principal investigator Alan Stern in his June 11 update, aptly titled “Childhood’s End.”
What’ll be particularly exciting for us space fans is an animation of Pluto and Charon in motion around each other, to be made from new observations to be acquired in July. Because of New Horizons’ position, the view will be from a perspective not possible from Earth.
New Horizons LOng Range Reconnaissance Imager (LORRI) image of Pluto and Charon from July 2013 (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
The next major milestone for New Horizons will be its crossing of Neptune’s orbit on August 25. (This just happens to fall on the 25th anniversary of Voyager 2’s closest approach in 1989.) “After that,” Stern says, “we’ll be in ‘Pluto space!'”
Launched on Jan. 19, 2006, New Horizons will make its closest approach to Pluto on July 14, 2015 at 11:49 UTC. Traveling nearly 35,000 mph (55,500 km/h) it’s one of the fastest vehicles ever built, moving almost 20 times faster than a bullet.
Read more from Alan Stern in his latest “PI Perspective” article on the New Horizons web site here, and check out NASA’s mission page here for the latest news as well.
“There is a lot to tell you about over the next 12 weeks, and this is just the warm-up act. Showtime — the start of the encounter — begins in just six months. This is what New Horizons was built for, and what we came to do. In a very real sense, the mission is emerging into its prime.”
– Alan Stern, New Horizons principal investigator
Also, check out a video on Pluto and the New Horizons mission here.
It’s a lot of speculation right now, but the buzz in a new NASA study is Pluto’s largest moon (Charon) could have a cracked surface.
If the New Horizons mission catches these cracks when it whizzes by in 2015, this could hint at an ocean underneath the lunar surface — just like what we talk about with Europa (near Jupiter) and Enceladus (near Saturn). But don’t get too excited — it’s also possible Charon had an ocean, but it froze out over time.
“Our model predicts different fracture patterns on the surface of Charon depending on the thickness of its surface ice, the structure of the moon’s interior and how easily it deforms, and how its orbit evolved,” stated Alyssa Rhoden of NASA’s Goddard Space Flight Center in Maryland, who led the research.
“By comparing the actual New Horizons observations of Charon to the various predictions, we can see what fits best and discover if Charon could have had a subsurface ocean in its past, driven by high eccentricity.”
It seems an unlikely proposition given that Pluto is so far from the Sun — about 29 times further away than the Earth is. Its surface temperature is -380 degrees Farhenheit (-229 degrees Celsius), which — to say the least — would not be a good environment for liquid water on the surface.
But it could happen with enough tidal heating. To back up, both Europa and Enceladus are small moons fighting gravity from their much larger gas giant planets, not to mention a swarm of other moons. This “tug-of-war” not only makes their orbits eccentric, but creates tides that change the interior and the surface, causing the cracks. Perhaps this might have kept subsurface oceans alive on these moons.
Encaladus, a moon of Saturn, as shown in this Voyager 1 image. Credit: NASA
Since Charon once had an eccentric orbit, perhaps it also had tidal heating. Scientists think that the moon was created after a large object smacked into Pluto and created a chain of debris (similar to the leading theory for how our Moon was formed). The proportionally huge Charon — it’s one-eighth Pluto’s mass — would have been close to its parent planet, causing gravity to tug on both objects and creating friction inside their interiors.
“This friction would have also caused the tides to slightly lag behind their orbital positions,” NASA stated. “The lag would act like a brake on Pluto, causing its rotation to slow while transferring that rotational energy to Charon, making it speed up and move farther away from Pluto.”
But this friction would have ceased long ago, given that observations show Charon orbits in a stable circle further away from Pluto, and there are no extraneous tugs on its path today. So another possibility is there was an ocean beneath the moon’s surface that today is a block of ice.
An artist’s conception of a KBO encounter by New Horizons. Credit: JHUAPL/SwRI.
Are you ready for the summer of 2015? A showdown of epic proportions is in the making, as NASA’s New Horizons spacecraft is set to pass within 12,500 kilometres of Pluto — roughly a third of the distance of the ring of geosynchronous satellites orbiting the Earth — a little over a year from now on July 14th, 2015.
But another question is already being raised, one that’s assuming center stage even before we explore Pluto and its retinue of moons: will New Horizons have another target available to study for its post-Pluto encounter out in the Kuiper Belt? Researchers say time is of the essence to find it.
To be sure, it’s a big solar system out there, and it’s not that researchers haven’t been looking. New Horizons was launched from Cape Canaveral Air Force Station on January 19th, 2006 atop an Atlas V rocket flying in a 551 configuration in one of the fastest departures from Earth ever: it took New Horizons just nine hours to pass Earth’s moon after launch.
New Horizons spends its last days on Earth pre-encapsulation. (Credit: NASA/KSC).
The idea has always been out there to send New Horizons onward to explore and object beyond Pluto in the Kuiper Belt, but thus far, searches for a potential target have turned up naught.
A recent joint statement from NASA’s Small Bodies and Outer Planets Assessment Groups (SBAG and OPAG) has emphasized the scientific priority needed for identifying a possible Kuiper Belt Object (KBO) for the New Horizons mission post-Pluto encounter. The assessment notes that such a chance to check out a KBO up close may only come once in our lifetimes: even though it’s currently moving at a heliocentric velocity of just under 15 kilometres a second, it will have taken New Horizons almost a decade to traverse the 32 A.U. distance to Pluto.
The report also highlights the fact that KBOs are expected to dynamically different from Pluto as well and worthy of study. The statement also notes that the window may be closing to find such a favorable target after 2014, as the upcoming observational apparition of Pluto as seen from Earth — and the direction New Horizons is headed afterwards — reaches opposition this summer on July 4th.
But time is of the essence, as it will allow researchers to plan for a burn and trajectory change for New Horizons shortly after its encounter with Pluto and Charon using what little fuel it has left. Then there’s the issue of debris in the Pluto system that may require fine-tuning its trajectory pre-encounter as well. New Horizons will begin long range operations later this year in November, switching on permanently for two years of operations pre-, during and post- encounter with Pluto.
And there currently isn’t a short-list of “next best thing” targets for New Horizons post-Pluto encounter. One object, dubbed VNH0004, may be available for distant observations in January of next year, but even this object will only pass 75 million kilometres — about 0.5 A.U. — from New Horizons at its closest.
Ground based assets such as the Keck, Subaru and Gemini observatories have been repeatedly employed in the search over the past three years. The best hopes lie with the Hubble Space Telescope, which can go deeper and spy fainter targets.
Nor could New Horizons carry out a search for new targets on its own. Its eight inch (20 cm in diameter) LORRI instrument has a limiting magnitude of about +18, which is not even close to what would be required for such a discovery.
New Horizons currently has 130 metres/sec of hydrazine fuel available to send it onwards to a possible KBO encounter, limiting its range and maneuverability into a narrow cone straight ahead of the spacecraft. This restricts the parameters for a potential encounter to 0.35 A.U. off of its nominal path for a target candidate be to still be viable objective. New Horizons will exit the Kuiper Belt at around 55 A.U. from the Sun, and will probably end its days joining the Voyager missions probing the outer solar system environment. Like Pioneers 10 and 11, Voyagers 1 and 2 and the upper stage boosters that deployed them, New Horizons will escape our solar system and orbit the Milky Way galaxy for millions of years. We recently proposed a fun thought experiment concerning just how much extraterrestrial “space junk” might be out there, littering the galactic disk.
And while the crowd-sourced Ice Hunters project generated lots of public engagement, a suitable target wasn’t found. There is talk of a follow up Ice Investigators project, though it’s still in the pending stages.
Another issue compounding the problem is the fact that Pluto is currently crossing the star rich region of the Milky Way in the constellation Sagittarius. Telescopes looking in this direction must contend with the thousands of background stars nestled towards the galactic center, making the detection of a faint moving KBO difficult. Still, if any telescope is up to the task, it’s Hubble, which just entered its 25th year of operations last month.
The path of Pluto through the constellation Sagittarius through August 2015. Credit: Starry Night.
Shining at +14th magnitude, Pluto will be very near the 3.5th magnitude star Xi2 Sagittarii during the July 2015 encounter.
New Horizons is currently 1.5 degrees from Pluto — about 3 times the angular size of a Full Moon —as seen from our Earthly vantage point, and although neither can be seen with the naked eye, you can wave in their general direction this month on May 18th, using the nearby daytime Moon as a guide.
The waning crescent Moon lies in the direction of New Horizons and Pluto on May 18th… note the ESA’s Rosetta spacecraft (lower left) and Pioneer 11 (upper center) are also ‘nearby!’ Credit: Starry Night
July 2015 will be an exciting and historic time in solar system exploration. Does Pluto have more undiscovered moons? A ring system of its own? Does it resemble Neptune’s moon Triton, or will it turn out looking entirely different ?
If nothing else, exploration of Pluto will finally give us science writers some new images to illustrate articles on the distant world, rather than recycling the half a dozen-odd photos and artist’s conceptions that are currently available. An abundance of surface features will then require naming as well. It would be great to see Pluto’s discoverer Clyde Tombaugh and Venetia Burney — the girl who named Pluto — get their due. We’ll even assume our space pundit’s hat and predict a resurgence of the “is it a planet?” debate once again in the coming year as the encounter nears…
Artist's impression of New Horizons' encounter with Pluto and Charon. Credit: NASA/Thierry Lombry
Less than a year from now, the New Horizons spacecraft will begin its encounter with Pluto. While closest approach is scheduled for July 2015, the Long Range Reconnaissance Imager or “LORRI” will begin snapping photos of the Pluto system six months earlier.
This first mission to Pluto has been a long time coming, and this new “trailer” put out by the New Horizons team recounts what it has taken to send the fastest spacecraft ever on a 5 billion km (3 billion mile) journey to Pluto, its largest moon, Charon, and the Kuiper Belt beyond. The spacecraft has been zooming towards the edge of our Solar System for over eight years since it launched on January 19, 2006.
By late April 2015, the approaching spacecraft will be taking pictures of Pluto that surpass the best images to date from Hubble. By closest approach in July 2015 –- when New Horizons will be 10,000 km from Pluto — a whole new world will open up to the spacecraft’s cameras. If New Horizons flew over Earth at the same altitude, it’s cameras could see individual buildings and their shapes.
“Humankind hasn’t had an experience like this–an encounter with a new planet–in a long time,” said Alan Stern, New Horizons’ principal investigator. “Everything we see on Pluto will be a revelation.”
It’s likely there could be some new planetary bodies discovered during the mission in addition to the five known moons: Charon, Styx, Nix, Kerberos, and Hydra.
“There is a real possibility that New Horizons will discover new moons and rings as well,” says Stern.
No matter what, Stern said, this is going to be an amazing ride.
“We’re flying into the unknown,” he said, “and there is no telling what we might find.”
See the countdown clock and find out more about the mission at the New Horizons website.
Another blow was dealt to deep space exploration this past weekend. The announcement comes from Jim Green, NASA’s Planetary Science Division Director. The statement outlines some key changes in NASA’s radioisotope program, and will have implications for the future exploration of the outer solar system.
An Advanced Stirling Converter prototype in the laboratory. (Credit: NASA).
Artist's impression of the New Horizons spacecraft. Image Credit: NASA
Now that’s a tune for a space geek’s ears. This is a highly modified sound bite of ranging signals between the Pluto-bound New Horizons spacecraft with NASA’s Deep Space Network (DSN) receiving stations.
What are the changes? The frequency has been altered to something that human ears can hear, explained a scientist in a New Horizons blog post this week:
“The ranging technique is just like seeing how much time it takes to hear the echo of your voice reflected off some object to measure how far away you are,” stated Chris DeBoy, New Horizons telecommunications system lead engineer who is with the Johns Hopkins Applied Physics Laboratory.
The ranging code first emanated from the DSN, which sent it to New Horizons. The spacecraft demodulated (or processed) the signal and sent it back to Earth. The DSN then calculated the delay (in seconds) between when it sent the signal, and when the answer was received.
“The DSN’s ‘voice’ is a million or more times higher in frequency than your voice, travels almost a million times faster than the speed of sound, and the round-trip distance is more than four billion miles,” DeBoy added.
In this case, the signals were sent June 29, 2012 from a DSN station in Goldstone, California. The answer arrived at a fellow DSN station in Canberra, Australia and yielded a round trip time of six hours, 14 minutes and 29 seconds.
Despite its great distance away, New Horizons is still almost two years from its brief encounter with Pluto and its moons in July 2015. Some interesting trivia about the mission: some Plutonian moons were discovered while the spacecraft was en route. Shows how quickly science changes in a few years.
