A review of what little we know of Pluto prior to New Horizons’ arrival

The principle investigator of the New Horizons mission to Pluto gives us an overview of what is known, and what we might find, when the spacecraft does its fly-by on July 14.

Pluto has very distinct surface markings, including apparent polar caps, and it has an atmosphere (mostly nitrogen). We know that Pluto’s interior is primarily made of rock — about 70% by mass. Also, Pluto-Charon constitute a true binary planet, with a barycenter (center of mass) situated in the open space between them. We know Charon is a “rising star” among the solar system’s icy bodies, with evidence for recently created surface ices, possible internal activity (hinted at by the spectroscopic discovery of ammonium hydrates a few years ago), and some likelihood of an atmosphere itself — perhaps gas that was siphoned off Pluto! As for the small satellites — Styx, Nix, Kerberos, and Hydra — we know very little about them beyond their orbits and crude colors. Soon all six of those points of light, planet and moons, will be real worlds thanks to NASA’s New Horizons.

He also admits that trying to guess what we might find is quite hazardous, and likely will end up wrong.

Latest images from New Horizons see Pluto’s polar cap

Images taken between April 12 and April 18 by New Horizons of Pluto not only show one complete rotation of the planet as well as its moon Charon, the images also show a bright spot at Pluto’s pole that could be a polar cap.

The article calls it an “ice cap” but that is premature. At Pluto that cap could be made of a number of materials, not just water. We will not know until New Horizons gets closer.

New Horizons begins Pluto approach phase 2 of 3

It’s getting closer! On April 5 New Horizons began the second of three approach phases in preparing for its July 14 fly-by of Pluto.

During this phase, which lasts until June 23, the spacecraft’s instruments will take the first ever color and spectral photos of the Pluto system. Observations taken during this period will provide sharper focus of Pluto and its five moons. Long exposure images will scan the region for additional moons and a possible ring system. Ultraviolet observation of both the surfaces and atmospheres of Pluto and Charon will begin during this phase.

The main goal of these observations, besides gazing at Pluto and its five moons, is to scan the region that the spacecraft will pass through, and make sure there is nothing there that might pose a threat.

Want to help name Pluto’s features? You can!

The New Horizons science team is asking the public to help name the planet’s features it expects to see when the spacecraft flies past Pluto on July 14.

I should mention that the project scientist for New Horizons is Alan Stern, who also happened to be a major player in the private space effort called Uwingu, which previously offered the public the opportunity to name features on Mars, without IAU approval.

In the case of New Horizons, Stern is kind of forced to work with the IAU, since the project is funded by NASA and NASA would never challenge a fellow bureaucracy like IAU.

Week long movie of Pluto produced by New Horizons

Cool images! Using New Horizons’ long range camera scientists have compiled a movie showing Charon and Pluto orbiting each other during the last week of January 2015.

Pluto and Charon were observed for an entire rotation of each body; a “day” on Pluto and Charon is 6.4 Earth days. The first of the images was taken when New Horizons was about 3 billion miles from Earth, but just 126 million miles (203 million kilometers) from Pluto—about 30% farther than Earth’s distance from the Sun. The last frame came 6½ days later, with New Horizons more than 5 million miles (8 million kilometers) closer.

The wobble easily visible in Pluto’s motion, as Charon orbits, is due to the gravity of Charon, about one-eighth as massive as Pluto and about the size of Texas.

Our view of Pluto, and Charon, is only going to get better as New Horizons zooms towards its July fly-by.

New Pluto images from New Horizons

Pluto from 126 million miles

The New Horizons science team has finally released the navigation image of Pluto and Charon that the spacecraft took on January 25.

A cropped version is on the right. The image shows Pluto and its biggest moon Charon, with both appearing somewhat elongated in shape. Why this is so is not explained by the press release, but I suspect it is because the goal of the image was not sharpness but to locate the planet for navigation purposes.

New Horizons to begin observations of Pluto

In preparing for its July 14 fly-by of Pluto, New Horizons will take its first images of the planet on January 25.

Snapped by New Horizons’ telescopic Long-Range Reconnaissance Imager, known as LORRI, those pictures will give mission scientists a continually improving look at the dynamics of those moons. And they’ll play a critical role in navigating the spacecraft as it covers the remaining 135 million miles (220 million kilometers) to Pluto. “We’ve completed the longest journey any craft has flown from Earth to reach its primary target, and we are ready to begin exploring!” said Alan Stern, New Horizons principal investigator from Southwest Research Institute in Boulder, Colorado.

Over the next few months, LORRI will take hundreds of pictures of Pluto against star fields to refine the team’s estimates of New Horizons’ distance to Pluto. Though the Pluto system will resemble little more than bright dots in the camera’s view until May, mission navigators will use those data to design course-correction maneuvers that aim the spacecraft toward its flyby target point this summer. The first such maneuver could occur as early as March.

New Horizons awakes

After almost nine years of travel the American New Horizons probe has been successfully awakened in preparation for its July fly-by of Pluto.

Since launching on January 19, 2006, New Horizons has spent 1,873 days — about two-thirds of its flight time — in hibernation. Its 18 separate hibernation periods, from mid-2007 to late 2014, ranged from 36 days to 202 days in length. The team used hibernation to save wear and tear on spacecraft components and reduce the risk of system failures. “Technically, this was routine, since the wake-up was a procedure that we’d done many times before,” said Glen Fountain, New Horizons project manager at APL. “Symbolically, however, this is a big deal. It means the start of our pre-encounter operations.”

By mid-May we will begin to see images of Pluto and its moons that are better than any images ever before taken.

Three potential post-Pluto targets for New Horizons

After completing a deep search using the Hubble Space Telescope, scientists have identified three Kuiper Belt Objects (KBO) that New Horizons can actually reach after it flies past Pluto next year.

The KBOs Hubble found are each about 10 times larger than typical comets, but only about 1-2 percent of the size of Pluto. Unlike asteroids, KBOs have not been heated by the sun and are thought to represent a pristine, well preserved deep-freeze sample of what the outer solar system was like following its birth 4.6 billion years ago. The KBOs found in the Hubble data are thought to be the building blocks of dwarf planets such as Pluto.

I think it remarkable that in the vastness beyond Pluto they were able to find any objects that also happen to be within the narrow path that New Horizons must fly after it passes Pluto in July.

Nothing for New Horizons after Pluto

As New Horizons begins its final shake-down in advance of its July 2015 flyby of Pluto, scientists have so far failed to find any Kuiper Belt objects in the right place for it to fly past after Pluto.

They haven’t given up hope, however. The search continues. As for the Pluto flyby,

The hibernating spacecraft will send weekly status beacons back to Earth, with wakeup scheduled for Dec. 7 to begin the final phase of its approach to Pluto. New Horizons will stay awake for two years to prepare for the encounter, fly by Pluto, and downlink science data. The craft’s appointment with Pluto is set for July 14, 2015, when it will zoom about 6,200 miles from the icy world’s unmapped surface for a one-shot chance to explore Pluto’s geology and atmosphere.

Hubble to search for Kuiper Belt targets for New Horizons

After completing a preliminary search for potential Kuiper Belt objects which the Pluto probe New Horizons might visit, scientists have decided to use the space telescope for a deeper more complete search.

As a first step, Hubble found two KBOs drifting against the starry background. They may or may not be the ideal target for New Horizons. Nevertheless, the observation is proof of concept that Hubble can go forward with an approved deeper KBO search, covering an area of sky roughly the angular size of the full Moon. The exceedingly challenging observation amounted to finding something no bigger than Manhattan Island, and charcoal black, located 4 billion miles away.

More here.

The astronomers who allocate time on the Hubble Space Telescope have decided to devote a large block for finding a Kuiper Belt object that the probe New Horizons might fly past.

The astronomers who allocate time on the Hubble Space Telescope have decided to devote a large block for finding a Kuiper Belt object that the probe New Horizons might fly past.

This allocation is still contingent upon a test observation to see if Hubble will be able to spot enough objects to make the long observations worthwhile.

Designed and funded on the premise that it would fly past a Kuiper belt asteroid after it flew past Pluto, the New Horizons team has so far failed to find such an asteroid and is running out of time.

Designed and funded on the premise that it would fly past a Kuiper belt object (KBO) after it flew past Pluto, the New Horizons team has so far failed to find such an asteroid and is running out of time.

In theory, project scientists should have identified a suitable KBO long ago. But they postponed their main search until 2011, waiting for all the possible KBO targets to begin converging on a narrow cone of space that New Horizons should be able to reach after its Pluto encounter. Starting to look for them before 2011 would have been impossible, says Grundy, because they would have been spread over too much of the sky.

Now that the hunt for KBOs is on, the New Horizons researchers have mainly been using the 8.2-metre Subaru Telescope in Hawaii and the 6.5-metre Magellan Telescopes in Chile. They have found about 50 new KBOs; none is close enough for New Horizons to reach.

I always thought it unlikely that they would be able to, on the fly, find a suitable candidate that New Horizons could reach in the very empty vastness beyond Pluto. In fact, it seemed absurd and to me seemed instead a transparent public relations ploy to get the funding for the fly-by mission to Pluto. Sadly, my cynical perspective here appears to be turning out to be true.

Engineers have decided to keep the New Horizons spacecraft on its original fly-by path past Pluto, scheduled for July 2015.

Engineers have decided to keep the New Horizons spacecraft on its original fly-by path past Pluto, scheduled for July 2015.

The New Horizons team recently completed an 18-month study of potential impact hazards – mostly dust created by objects hitting Pluto’s small satellites – the spacecraft would face as it speeds some 30,000 miles per hour (more than 48,000 kilometers per hour) past Pluto in July 2015. The team estimated that the probability of a mission-ending dust impact was less than 0.3 percent if the spacecraft followed the current baseline plan, far below some early, more conservative estimates. So, with the concurrence of an independent review panel and NASA, the project team expects to keep New Horizons on this baseline course, which includes a close approach of about 12,500 kilometers (nearly 7,800 miles) from the surface of Pluto.

The science team for New Horizons is considering shifting the spacecraft’s Pluto flyby away from the planet to avoid orbital debris.

The science team for New Horizons is considering shifting the spacecraft’s Pluto flyby away from the planet to avoid orbital debris.

“We’ve found more and more moons orbiting near Pluto — the count is now up to five,” Stern said. “And we’ve come to appreciate that those moons, as well as others not yet discovered, act as debris generators populating the Pluto system with shards from collisions between those moons and small Kuiper Belt objects.”

New Horizons — on its way to Pluto — will take a look at a different Kuiper Belt object in January 2015.

New Horizons — on its way to Pluto — will take a look at a different Kuiper Belt object in January 2015.

The encounter will take place at a range of about 75 million km, a distance somewhat subject to change depending on how the probe makes its course correction. At such a great distance, New Horizons will not be able to discern features on the surface of the KBO, nor will it be able to make spectroscopic observations to try to determine the composition of the surface material.

However, New Horizons will be in an excellent position to look for small, close-in moons around the object. It will also be in a position to observe the object’s phase curve, which is a measure of how the reflectivity of the surface changes as a function of viewing angle. This will reveal a great deal about the fluffiness of the surface material (note – fluffiness is a technical term meaning, roughly, “the opposite of dense”). These two observations cannot be made from Earth, even with the most powerful telescopes available.

1 3 4 5