Posted on by Ken Kremer

Solar Powered Jupiter bound JUNO lands at Kennedy Space Center for blastoff

The Juno spacecraft passes in front of Jupiter in this artist's depiction. Juno, the second mission in NASA's New Frontiers program, will improve our understanding of the solar system by advancing studies of the origin and evolution of Jupiter. The spacecraft will carry eight instruments to investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. Credit: NASA/JPL-Caltech

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Juno, NASA’s next big mission bound for the outer planets, has arrived at the Kennedy Space Center to kick off the final leg of launch preparations in anticipation of blastoff for Jupiter this summer.

The huge solar-powered Juno spacecraft will skim to within 4800 kilometers (3000 miles) of the cloud tops of Jupiter to study the origin and evolution of our solar system’s largest planet. Understanding the mechanism of how Jupiter formed will lead to a better understanding of the origin of planetary systems around other stars throughout our galaxy.

Juno will be spinning like a windmill as it fly’s in a highly elliptical polar orbit and investigates the gas giant’s origins, structure, atmosphere and magnetosphere with a suite of nine science instruments.

Technicians at Astrotech's payload processing facility in Titusville, Fla. secure NASA's Juno spacecraft to the rotation stand for testing. The solar-powered spacecraft will orbit Jupiter's poles 33 times to find out more about the gas giant's origins. Credit: NASA/Jack Pfaller

During the five year cruise to Jupiter, the 3,600 kilogram probe will fly by Earth once in 2013 to pick up speed and accelerate Juno past the asteroid belt on its long journey to the Jovian system where it arrives in July 2016.

Juno will orbit Jupiter 33 times and search for the existence of a solid planetary core, map Jupiter’s intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet’s auroras.

The mission will provide the first detailed glimpse of Jupiter’s poles and is set to last approximately one year. The elliptical orbit will allow Juno to avoid most of Jupiter’s harsh radiation regions that can severely damage the spacecraft systems.

Juno was designed and built by Lockheed Martin Space Systems, Denver, and air shipped in a protective shipping container inside the belly of a U.S. Air Force C-17 Globemaster cargo jet to the Astrotech payload processing facility in Titusville, Fla.

Juno undergoes acoustics testing at Lockheed Martin in Denver where the spacecraft was built. Credit: NASA/JPL-Caltech/Lockheed Martin

This week the spacecraft begins about four months of final functional testing and integration inside the climate controlled clean room and undergoes a thorough verification that all its systems are healthy. Other processing work before launch includes attachment of the long magnetometer boom and solar arrays which arrived earlier.

Juno is the first solar powered probe to be launched to the outer planets and operate at such a great distance from the sun. Since Jupiter receives 25 times less sunlight than Earth, Juno will carry three giant solar panels, each spanning more than 20 meters (66 feet) in length. They will remain continuously in sunlight from the time they are unfurled after launch through the end of the mission.

“The Juno spacecraft and the team have come a long way since this project was first conceived in 2003,” said Scott Bolton, Juno’s principal investigator, based at Southwest Research Institute in San Antonio, in a statement. “We’re only a few months away from a mission of discovery that could very well rewrite the books on not only how Jupiter was born, but how our solar system came into being.”

Juno is slated to launch aboard the most powerful version of the Atlas V rocket – augmented by 5 solid rocket boosters – from Cape Canaveral, Fla. on August 5. The launch window extends through August 26. Juno is the second mission in NASA’s New Frontiers program.

NASA’s Mars Curiosity Rover will follow Juno to the Atlas launch pad, and is scheduled to liftoff in late November 2011. Read my stories about Curiosity here and here.

Because of cuts to NASA’s budget by politicians in Washington, the long hoped for mission to investigate the Jovian moon Europa may be axed, along with other high priority science missions. Europa may harbor subsurface oceans of liquid water and is a prime target in NASA’s search for life beyond Earth.

Technicians inside the clean room at Astrotech in Titusville, Fla. guide NASA's Juno spacecraft, as it is lowered by overhead crane, onto the rotation stand for testing. Credit: NASA/Jack Pfaller
Technicians at Astrotech unfurl solar array No. 1 with a magnetometer boom that will help power NASA's Juno spacecraft on a mission to Jupiter. Credit: NASA
Juno's interplanetary trajectory to Jupiter. Juno will launch in August 2011 and fly by Earth once in October 2013 during its 5 year cruise to Jupiter. Click to enlarge. Credit: NASA/JPL
Posted on by Nancy Atkinson

New Horizons Flies by Uranus

An 'overhead' view of New Horizons' location. Credit: NASA

The Pluto-bound New Horizons spacecraft will fly by another planet today (March 18, 2011). However, the robotic craft won’t be taking any images as it zooms past Uranus’ orbit at about 6 p.m. EDT, 3.8 billion kilometers (2.4 billion miles) away from the gas giant (and 2.0 billion km (1.8 billion miles) from Earth). New Horizons is currently in hibernation mode, and the great distance from Uranus means any observations wouldn’t provide much as far as data and images. But, even so, this event is a ‘landmark’ so to speak in New Horizon’s gauntlet across the solar system.

“New Horizons is all about delayed gratification, and our 9 1/2-year cruise to the Pluto system illustrates that,” said Principal Investigator Alan Stern, of the Southwest Research Institute. “Crossing the orbit of Uranus is another milepost along our long journey to the very frontier of exploration.”

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New Horizons is now well over halfway through its journey to Pluto. Motoring along at 57,900 km/hr (36,000 mph), it will travel more than 4.8 billion km (3 billion miles) to fly past Pluto and its moons Nix, Hydra and Charon in July 2015.

But the journey doesn’t end there. After that, New Horizons will head off to a post-Pluto encounter with other objects within the Kuiper Belt, some event(s) which might take place even into the 2020’s. The planetary science community is working on the selection of potential targets.

The mission still has more than 4 years to go to get to Pluto; it will take 9 nine months to send all the data back to Earth.

The next planetary milestone for New Horizons will be the orbit of Neptune, which it crosses on Aug. 25, 2014, exactly 25 years after Voyager 2 made its historic exploration of that giant planet.

“This mission is a marathon,” says Project Manager Glen Fountain, of the Johns Hopkins University Applied Physics Laboratory. “The New Horizons team has been focused on keeping the spacecraft on course and preparing for Pluto. So far, so good, and we are working to keep it that way.”

Source: New Horizons

Posted on by Nancy Atkinson

New Horizons Mission Practices Telescopic Imager on Pluto’s Twin

New Horizons image of Neptune and its largest moon, Triton. June 23, 2010. Credit: NASA

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This summer, the New Horizons spacecraft was awoken for its annual systems checkout, and took the opportunity to exercise the long range camera by snapping pictures of Neptune, which at the time, was 3.5 billion km (2.15 billion miles) away. The Long Range Reconnaissance Imager (LORRI) snapped several photos of the gas giant, but Neptune was not alone! The moon Triton made a cameo appearance. And the New Horizons team said that since Triton is often called Pluto’s “twin” it was perfect target practice for imaging its ultimate target, Pluto.

This image gets us excited for 2015 when New Horizons will approach and make the closest flyby ever of Pluto.

“That we were able to see Triton so close to Neptune, which is approximately 100 times brighter, shows us that the camera is working exactly as designed,” said New Horizons Project Scientist Hal Weaver, of the Johns Hopkins Applied Physics Laboratory. “This was a good test for LORRI.”

Weaver pointed out that the solar phase angle (the spacecraft-planet-Sun angle) was 34 degrees and the solar elongation angle (planet-spacecraft-Sun angle) was 95 degrees. Only New Horizons can observe Neptune at such large solar phase angles, which he says is key to studying the light-scattering properties of Neptune’s and Triton’s atmospheres.

“As New Horizons has traveled outward across the solar system, we’ve been using our imagers to make just such special-purpose studies of the giant planets and their moons because this is a small but completely unique contribution that New Horizons can make — because of our position out among the giant planets,” said New Horizons Principal Investigator Alan Stern.

Triton is slightly larger than Pluto, 2,700 kilometers (1,700 miles) in diameter compared to Pluto’s 2,400 kilometers (1,500 miles). Both objects have atmospheres composed mostly of nitrogen gas with a surface pressure only 1/70,000th of Earth’s, and comparably cold surface temperatures approaching minus-400 degrees Fahrenheit. Triton is widely believed to have been a member of the Kuiper Belt (as Pluto still is) that was captured into orbit around Neptune, probably during a collision early in the solar system’s history.

Source: New Horizons

Posted on by Nancy Atkinson

New Horizons Spacecraft Now Closer to Pluto Than Earth

Fastest Spacecraft
Artist concept of the New Horizons spacecraft. Credit: NASA/JPL

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The New Horizons spacecraft crossed a milestone boundary today: it is now closer to its primary destination, Pluto, than to Earth. But New Horizons –the fastest man-made object — is not yet halfway to the dwarf planet. That won’t happen until February 25, 2010. New Horizons is now 1,440 days into its 9.5-year journey and well past 15 AU (astronomical units) from the Sun. But there is a long haul yet to go: there are still 1,928 days until operations begin for the close encounter, and 2022 days until the spacecraft reaches the closest point to Pluto in the summer of 2015. It is exciting to think what we will learn about Pluto and the Kuiper Belt in five and a half years. Will our perspectives change? Hard to believe they won’t.

New Horizons is currently traveling at about 50,000 kph (31,000 mph) (relative to the Sun) and is located about 2.4 billion kilometers (1.527 billion miles) from Earth.

The spacecraft launched in January 2006.

New Horizons will be taken out of hibernation in early January to repoint the communications dish antenna to keep up with the changing position of the Earth around the Sun. It was last awoken in November to download several months of stored science data from the Venetia Burney Student Dust Counter, to correct a recently discovered bug in the fault protection system software, (last thing anyone wants is to have the spacecraft go into safe mode at closest approach), and to upload instructions to run the spacecraft through early January. Telemetry shows that New Horizons is in very good health and almost exactly on its planned course.

Principal Investigator Alan Stern wrote in his last PI’s Perspective notes that the science team will meet in January to discuss which Kuiper Belt Objects they hope to “fly by and reconnoiter after Pluto. Those searches will begin next summer and continue through 2011 and 2012. Hopefully, they’ll net us four to 10 potential targets.”

Posted on by Ian O'Neill

Pluto’s Moons, Nix and Hydra, may have been Adopted

The discovery images of Nix (and Hydra) obtained by the Hubble Space Telescope. Credit: NASA, ESA, H. Weaver (JHU/APL), A. Stern (SwRI)

 

How many moons does Pluto have? The mini-moons of Pluto, Nix and Hydra, were discovered in 2005 (but named in 2006) during an observation campaign by the Hubble Space Telescope. The discovery of these mini-moons increase the number of natural satellites orbiting Pluto to three (including larger moon Charon). But where did these satellites come from? The current accepted theory on the formation on the large moon, Charon, is much like the theory supporting the creation of Earth’s Moon. It is thought that a large impact between two Large Kuiper Belt Objects chipped Charon away from a proto-Pluto, putting the chunk of Pluto mass into orbit. Over the years, tidal forces slowed the pair and Charon was allowed to settle into its present-day orbit. Recent theory suggests that Nix and Hydra are a by product of this collision, merely shattered fragments of the huge impact. But there are problems with this idea. Could Nix and Hydra have come from somewhere other than the Pluto-Charon impact?

The orbits of Plutos moons, Charon, Nix and Hydra (credit: NASA)
The small moons that orbit the Large Kuiper Belt Object (formerly classified as a planet) can be found about 48,700 kilometers and 64,800 kilometers from the surface of Pluto. The closest moon is called Nix and the farthest, Hydra. Nix has an orbital resonance of 4:1 with Charons orbit and the larger moon Hydra has a resonance of 6:1 (i.e. Nix will orbit Pluto once for every four of Charons orbits; Hydra will orbit Pluto once for every six of Charons orbits).

The reasons behind these mini-moon orbits are only just beginning to be understood, but it is known that their resonances with Charons orbit is rooted way back during the Pluto-system evolution. If we assume Hydra and Nix were formed from a massive Kuiper Belt Object collision, the easiest explanation is to assume they are whole fragments from the impact caught in the gravity of the Pluto-Charon system. However, due to the highly eccentric orbits that would have resulted from this collision, it is not possible that the two little moons could have evolved into a near-circular orbit, in near-corotational resonance with Charon.

So, could it be possible that the moons may have formed from the dust and debris resulting from the initial collision? If there was enough material produced, and if the material collided frequently, then perhaps Nix and Hydra were born from a cold disk of debris (rather than being whole pieces of rock), eventually coalescing and forming sizeable rocky moons. As there may have been a disk of debris, collisions with the orbiting Nix and Hydra would have also reduced any eccentricity in their orbits.

But there is a big problem with this theory. From impact simulations, the post-impact disk of debris surrounding Pluto would have been very compact. The disk could not have reached as far as the present-day orbits of the moons.

One more theory suggests that perhaps the moons were created in a post-impact disk, but very close to Pluto, and then through gravitational interactions with Charon, the orbits of Nix and Hydra were pulled outward, allowing them to orbit far from the Pluto-Charon post-impact disk. According to recent computer simulations, this doesn’t seem to be possible either.

To find an answer, work by Yoram Lithwick and Yanqin Wu (University of Toronto) suggest we must look beyond the Pluto-Charon system for a source of material for Nix and Hydra. From simulations, the above theories on the creation of the small moons being started by material ejected from a large collision between two Large Kuiper Belt Objects (creating Pluto and Charon) are extremely problematic. They do not correctly answer how the highly eccentric orbits Nix and Hydra would have from a collision could evolve into the near-circular ones they have today.

Lithwick and Wu go on to say that the circular, corotational resonant orbits of the two moons could be created from a Plutocentric disk of small bits of rock scooped up during Pluto’s orbit around the Sun. Therefore Nix and Hydra may have been formed from the rocky debris left over from the development of the Solar System, and not from a collision event creating Charon. This may hold true for the countless other Kuiper Belt Objects in orbit in the far reaches of the Solar System, no impact is necessary for the creation of the tiny moons now thought to be their satellites.

It is hoped that the New Horizons mission (launched January 21st, 2006) to the far reaches of the Solar System will reveal some of the questions that remain unanswered in the depths of our mysterious Kuiper Belt. Hopefully we will also find out whether Nix and Hydra are children of Pluto and Charon… or whether they were adopted.

Source: arXiv

Posted on by Nancy Atkinson

New Horizons Prepares to Zoom to Pluto

Artist impression of the New Horizons spacecraft sweeping past Pluto. Image credit: JHUAPL/SwRI. Click to enlarge.

If all goes well, the first mission to the farthest known planet in our Solar System will launch in early 2006, and give us our first detailed views of Pluto, its moon Charon, and the Kuiper Belt Region, while completing NASA’s reconnaissance of all the planets in our Solar System.

“We’re going to a planet that we’ve never been to before,” said Dr. Alan Stern, Principal Investigator for the New Horizons mission to Pluto. “This is like something out of a NASA storybook, like in the 60’s and 70’s with all the new missions that were happening then. But this is exploration for a new century; it’s something bold and different. Being the first mission to the last planet really ‘revs’ me. There’s something special about going to a new frontier, about

Pluto is so far away (5 billion km or 3.1 billion miles when New Horizons reaches it) that no telescope, not even the Hubble Space Telescope, has been able to provide a good image of the planet, and so Pluto is a real mystery world. The existence of Pluto has only been known for 75 years, and the debate continues about its classification as a planet, although most planetary scientists classify it in the new class of planets called Ice Dwarfs. Pluto is a large, ice-rock world, born in the Kuiper Belt area of our solar system. Its moon, Charon, is large enough that some astronomers refer to the two as a binary planet. Pluto undergoes seasonal change and has an elongated and enormous 248-year orbit which causes the planet’s atmosphere to cyclically dissipate and freeze out, but later be replenished when the planet returns closer to the sun.

New Horizons will provide the first close-up look at Pluto and the surrounding region. The grand piano-sized spacecraft will map and analyze the surface of Pluto and Charon, study Pluto’s escaping atmosphere, look for an atmosphere around Charon, and perform similar explorations of one or more Kuiper Belt Objects.

The spacecraft, built at the Johns Hopkins Applied Physics Laboratory, is currently being flight tested at the Goddard Space Flight Center. Dr. Stern has been planning a mission to Pluto for quite some time, surviving through the various on-again, off-again potential missions to the outer solar system.

“I’m feeling very good about the mission,” he said in an interview from his office at the Southwest Research Institute in Boulder, Colorado. “I’ve been working on this project for about 15 years, and the first 10 years we couldn’t even get it out of the starting blocks. Now we’ve not only managed to get it funded, but we have built it and we are really looking forward to flying the mission soon if all continues to go well.”

Of the hurdles remaining to be cleared before launch, one looms rather large. New Horizons’ systems are powered by a Radioisotope Thermoelectric Generator (RTG), where heat released from the decay of radioactive materials is converted into energy. This type of power system is essential for a mission going far from the Sun like New Horizons where solar power is not an option, but it has to be approved by both NASA and the White House. The 45-day public comment period ended in April 2005, so the project now awaits final, official approval. Meanwhile, the New Horizons mission teams prepare for launch.

“We still have a lot of work in front of us,” Stern said. “All this summer we’re testing and checking out the spacecraft and the components, getting all the bugs out, and making sure its launch ready, and flight ready. That will take us through September and in October we hope to bring the spacecraft to the Cape.”

The month-long launch window for New Horizons opens on January 11, 2006.

New Horizons will be the fastest spacecraft ever launched. The launch vehicle combines an Atlas V first stage, a Centaur second stage, and a STAR 48B solid rocket third stage.

“We built the smallest spacecraft we could get away with that has all the things it needs: power, communication, computers, science equipment and redundancy of all systems, and put it on the biggest possible launch vehicle,” said Stern. “That combination is ferocious in terms of the speed we reach in deep space.”

At best speed, the spacecraft will be traveling at 50 km/second (36 miles/second), or the equivalent of Mach 85.

Stern compared the Atlas rocket to other launch vehicles. “The Saturn V took the Apollo astronauts to the moon in 3 days,” he said. “Our rocket will take New Horizons past the moon in 9 hours. It took Cassini 3 years to get to Jupiter, but New Horizons will pass Jupiter in just 13 months.”

Still, it will take 9 years and 5 months to cross our huge Solar System. A gravity assist from Jupiter is essential in maintaining the 2015 arrival date. Not being able to get off the ground early in the launch window would have big consequences later on.

“We launch in January of 2006 and arrive at Pluto in July of 2015, best case scenario,” said Stern. “If we don’t launch early in the launch window, the arrival date slips because Jupiter won’t be in as good a position to give us a good gravity assist.”

New Horizons has 18 days to launch in January 2006 to attain a 2015 arrival. After that, Jupiter’s position moves so that for every 4 or 5 days delay in launch means arriving at Pluto year later. By February 14 the window closes for a 2020 arrival. New Horizons can try to launch again in early 2007, but then the best case arrival year is 2019.

New Horizons will be carrying seven science instruments:

  • Ralph: The main imager with both visible and infrared capabilities that will provide color, composition and thermal maps of Pluto, Charon, and Kuiper Belt Objects.
  • Alice: An ultraviolet spectrometer capable of analyzing Pluto’s atmospheric structure and composition.
  • REX: The Radio Science Experiment that measures atmospheric composition and surface temperature with a passive radiometer. REX also measures the masses of objects New Horizons flies by.
  • LORRI: The Long Range Reconnaissance Imager has a telescopic camera that will map Pluto?s far side and provide geologic data.
  • PEPSSI: The Pluto Energetic Particle Spectrometer Science Investigation that will measure the composition and density of the ions escaping from Pluto’s atmosphere.
  • SWAP: Solar Wind Around Pluto, which will measure the escape rate of Pluto?s atmosphere and determine how the solar wind affects Pluto.
  • SDC: The Student Dust Counter will measure the amount of space dust the spacecraft encounters on the voyage. This instrument was designed and will be operated by students at the University of Colorado in Boulder.

Stern says the first part of the flight will keep the mission teams busy, as they need to check out the entire spacecraft, and execute the Jupiter fly-by at 13 months.

“The middle years will be long and probably — and hopefully — pretty boring,” he said, but will include yearly spacecraft and instrument checkouts, trajectory corrections, instrument calibrations and rehearsals the main mission. During the last three years of the interplanetary cruise mission teams will be writing, testing and uploading the highly detailed command script for the Pluto/Charon encounter, and the mission begins in earnest approximately a year before the spacecraft arrives at Pluto, as it begins to photograph the region.

A mission to Pluto has been a long time coming, and is popular with a wide variety of people. Children seem to have an affinity for the planet with the cartoon character name, while the National Academy of Sciences ranked a mission to Pluto as the highest priority for this decade. In 2002, when it looked as though NASA would have to scrap a mission to Pluto for budgetary reasons, the Planetary Society, among others, lobbied strongly to Congress to keep the mission alive.

Stern said the mission’s website received over a million hits the first month it was active, and the hit rate hasn’t diminished. Stern writes a monthly column on the website, http://pluto.jhuapl.edu , where you can learn more details about the mission and sign-up to have your name sent to Pluto along with the spacecraft.

While Stern is understandably excited about this mission, he says that any chance to explore is a great opportunity.

“Exploration always opens our eyes,” he said. “No one expected to find river valleys on Mars, or a volcano on Io, or rivers on Titan. What do I think we’ll find at Pluto-Charon? I think we’ll find something wonderful, and we expect to be surprised.”