Raumfahrt+Astronomie-Blog von CENAP - Blog: Raumfahrt - NEW HORIZONS bei Pluto

Montag, 14. September 2015 - 19:15

Raumfahrt - NEW HORIZONS bei Pluto - Update-14

NASA’s New Horizons Spacecraft begins Intensive Data Downlink Phase

A Closer Look: This close-up image of a region near Pluto’s equator captured by New Horizons on July 14 reveals a range of youthful mountains rising as high as 11,000 feet (3.4 kilometers) above the surface of the dwarf planet. This iconic image of the mountains, informally named Norgay Montes (Norgay Mountains) was captured about 1 ½ hours before New Horizons’ closest approach to Pluto, when the craft was 47,800 miles (77,000 kilometers) from the surface of the icy body. The image easily resolves structures smaller than a mile across. The highest resolution images of Pluto are still to come, with an intense data downlink phase commencing on Sept. 5. (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

If you liked the first historic images of Pluto from NASA’s New Horizons s

spacecraft, you’ll love what’s to come.

Seven weeks after New Horizons sped past the Pluto system to study Pluto and its moons – previously unexplored worlds – the mission team will begin intensive downlinking of the tens of gigabits of data the spacecraft collected and stored on its digital recorders. The process moves into high gear on Saturday, Sept. 5, with the entire downlink taking about one year to complete.

“This is what we came for – these images, spectra and other data types that are going to help us understand the origin and the evolution of the Pluto system for the first time,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado. “And what’s coming is not just the remaining 95 percent of the data that’s still aboard the spacecraft – it’s the best datasets, the highest-resolution images and spectra, the most important atmospheric datasets, and more. It’s a treasure trove.”

Even moving at light speed, the radio signals from New Horizons containing data need more than 4 ½ hours to cover the 3 billion miles to reach Earth.

As a flyby mission, New Horizons was designed to gather as much information as it could, as quickly as it could, as it sped past Pluto and its family of moons – then store its wealth of data to its digital recorders for later transmission to Earth. Since late July, New Horizons has only been sending back lower data-rate information collected by the energetic particle, solar wind and space dust instruments. The pace picks up considerably on Sept. 5 as it resumes sending flyby images and other data.

During the data downlink phase, the spacecraft transmits science and operations data to NASA’s Deep Space Network (DSN) of antenna stations, which also provide services to other missions, like Voyager. The spacecraft’s distance from Earth slows communication rates, especially compared to rates offered by today’s high-speed Internet providers. With New Horizons past Pluto, the typical downlink rate is approximately 1-4 kilobits per second, depending on how the data is sent and which DSN antenna is receiving it.

“The New Horizons mission has required patience for many years, but from the small amount of data we saw around the Pluto flyby, we know the results to come will be well worth the wait,” said Hal Weaver, New Horizons project scientist from the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland.

The team also plans to continue posting new, unprocessed pictures from the Long Range Reconnaissance Imager (LORRI) on the New Horizons project website each Friday. The images are available here; the next LORRI set is scheduled for posting on Sept. 11.

New Horizons is part of NASA’s New Frontiers Program, managed by the agency’s Marshall Space Flight Center in Huntsville, Alabama. APL designed, built, and operates the New Horizons spacecraft and manages the mission for NASA’s Science Mission Directorate. SwRI leads the science mission, payload operations, and encounter science planning.

Dishing Out the Data: All communications with New Horizons – from sending commands to the spacecraft, to downlinking all of the science data from the historic Pluto encounter – happen through NASA’s Deep Space Network of antenna stations in (clockwise, from top left) Madrid, Spain; Goldstone, California, U.S.; and Canberra, Australia. Even traveling at the speed of light, radio signals from New Horizons need more than 4 ½ hours to travel the 3 billion miles between the spacecraft and Earth. (Image credit: NASA)

Quelle: NASA

Update: 6.09.2015

Pluto Revealed! An update from New Horizons

Professor Richard Binzel, NASA New Horizons science team co-PI, shares mission results on Sept. 9.

The MIT community is invited to join Department of Earth, Atmospheric and Planetary Sciences (EAPS) Professor Richard P. Binzel, a science team co-principal investigator for the NASA New Horizons mission to the Kuiper Belt, for an engaging review of what the encounter data have revealed so far. Binzel will speak in Room 10-250 on Wednesday, Sept. 9 from 4 to 5 p.m.

After nearly two decades of struggling for approval, the New Horizons mission finally reached the launch pad in January 2006. Nine-and-a-half years later, this past July, the piano-sized spacecraft reached the Pluto system, revealing an amazingly bizarre planetary world. Ice mountains as tall as the Rockies and smooth plains of frozen carbon monoxide 500 km across are just some of the surprising features seen. According to Binzel, Pluto appears to be a globally changing planet with seasonal cycles ranging from decades to millennia producing an evolving landscape of nitrogen ice glaciers and variable atmospheric pressure.

Pluto and its largest satellite, Charon, form a “double planet” system orbiting a common center of gravity located outside of either body. Charon’s surface also appears relatively young and crater-free, implying some recent era geologic activity. Completing the system are four small moons found to be irregularly shaped with complex spin patterns in their own regularly spaced orbits. As New Horizons continues its voyage out of the solar system, a close encounter with at least one newly discovered Kuiper Belt object appears possible within the next four years.

Binzel, who holds a joint appointment in the Department of Aeronautics and Astronautics, focuses his research on planetary spectroscopy, specializing in the visible to near-infrared wavelength reflectance properties of asteroids and meteorites. He has mapped the geology of the asteroid belt through such telescopic observations, cataloging the compositions of nearly 2,000 asteroids — with three new asteroid discoveries to his credit. In 1999, Binzel invented the Torino Scale, a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. Asteroid 2873 was named in his honor by the International Astronomical Union in recognition of his significant contributions to the field.

Pluto is another important facet of his research; he was on the Planet Definition Committee that developed the proposal to the International Astronomical Union's meeting in Prague in 2006 on whether Pluto should be considered a planet. While the outcome of the meeting determined Pluto to be a dwarf planet, Binzel strongly believes research shows Pluto to fulfill the criteria for full planet status. He is a co-investigator on the New Horizons mission, which has delivered the most detailed images and data to date of Pluto and its moons, gathered during its flyby only 7,750 miles from the surface.

In addition to being a co-investigator on the NASA New Horizons mission science team, he is a co-investigator on the OSIRIS-REx mission, which will launch in 2016 with the intent to retrieve samples from asteroid Bennu and return them to Earth in 2023 for study.

Binzel was awarded the H. C. Urey Prize by the American Astronomical Society in 1991, and was awarded a MacVicar Faculty Fellowship for teaching excellence at MIT in 1994. He has also edited several books regarding asteroid research. Binzel earned an undergraduate degree in physics from Macalester College, and a PhD in astronomy from the University of Texas.

Quelle: Massachusetts Institute of Technology

Update: 9.09.2015

New Horizons Probes the Mystery of Charon’s Red Pole

Details of Pluto’s largest moon, Charon, are revealed in this image from New Horizons’ Long Range Reconnaissance Imager (LORRI), taken July 13, 2015, from a distance of 289,000 miles (466,000 kilometers), combined with color information obtained by New Horizons’ Ralph instrument on the same day. The marking in Charon’s north polar region appears to be a thin deposit of dark material over a distinct, sharply bounded, angular feature; scientists expect to learn more by studying higher-resolution images still to come. (Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)

Hi, I’m Carly Howett, a senior research scientist at the Southwest Research Institute in Boulder, Colorado. I’ve been working on NASA’s New Horizons mission since 2012, focusing on an instrument named Ralph, which among other things provides the color “eyes” for the spacecraft.

When I started looking at Ralph images of Pluto and its largest moon, Charon, back in 2012, the bodies were so far away they appeared as just a speck of light, too close together to see separately. So you can imagine how excited I was to see Pluto and Charon not only as separate worlds this year, but with clear and different features across them. It is these differences, specifically across Charon, which have since been the focus of my work.

Surfaces vary in color when something about them changes; this difference could be due to composition (what the surface is made of) or physical state (changes between solid and liquid, or changes in their structure – for example at high-pressure carbon changes from graphite to diamond). We see this every day on Earth. For example, water looks different compared to sand and they both look different than ice. Another example of these differences is that carbon forms both the dark-colored graphite we use in pencils and clear sparkly diamonds. Looking at Charon, it’s very clear that the northern polar region is much redder than the rest of the moon. But what’s causing this color difference and why does it occur at the pole?

To answer the first part of this question we consider what we know about Charon. We know that Charon’s surface is too cold for anything other than solids to exist, and the surface isn’t subject to extreme changes in temperature and/or pressure, so it is unlikely significant phase transitions are occurring. Instead, we think that the color variation is due to a change in surface composition, which leads to the conclusion that the surface of Charon’s northern polar region is made up of different material than the rest of Charon.

One theory is that small amounts of Pluto’s atmosphere can escape and eventually reach Charon, where it would be temporarily trapped by Charon’s gravity before escaping to space. Charon’s polar regions are very cold, and I mean VERY cold! In fact, over the course of Charon’s year the polar temperature varies somewhere between -433 and -351 °F (-258 and -213 °C), which is only tens of degrees warmer than absolute zero. These temperatures (especially with Charon’s extremely thin atmosphere) are too cold to support surface liquid: gases are deposited straight to solids, and solids sublimate directly to gases. So — unlike at Charon’s warmer equator — any gases that arrive on the winter pole would freeze solid instead of escaping, a process scientists refer to as “cold trapping.” The basic principle that binary systems can share material is not new, but it took New Horizons to visit Charon to see its effect firsthand!

We know Pluto’s atmosphere is mainly nitrogen, with some methane and carbon monoxide, so we expect that these same constituents are slowly coating Charon’s winter pole. The frozen ices would sublimate away again as soon as Charon’s winter pole emerges back into sunlight, except for one important detail: solar radiation modifies these ices to produce a new substance, which has a higher sublimation temperature and can’t sublimate and then escape from Charon.

This new substance is called a tholin, and has been made in similar conditions in laboratories here on Earth. The color of the tholin produced depends on the ratios of the different molecules and the amount and type of radiation you expose them to: tholins colored from yellow to red to black have been made this way. An example of this (pictured above) shows various red tholins made in a laboratory by Sarah Hörst at Johns Hopkins University.

Charon likely has gradually built up a polar deposit over millions of years as Pluto’s atmosphere slowly escapes, during which time the surface is being irradiated by the sun. It appears the conditions on Charon are right to form red tholins similar to those shown, although we have yet to figure out exactly why. This is one of the many things I am looking forward to better understanding as we receive more New Horizons data over the next year and analyze it in conjunction with continued laboratory work.

Such an exciting time!

Quelle: NASA

Update: 10.09.2015

Aktuelle neue Bilder von New Horizon: