Ariane 5 Blasts Off with Two Satellites

Ariane 5 lift off from the Guiana Space Centre. Image credit: ESA Click to enlarge
The second member of Europe’s new generation of weather satellites has successfully been lifted onto orbit, continuing an uninterrupted series of launch successes since 1977.

This ninth Meteosat satellite, developed on behalf of EUMETSAT under the aegis of the European Space Agency, will reinforce EUMETSAT’s capacity to monitor the Earth atmosphere above Europe, Africa, the Middle-East and the Atlantic Ocean.

MSG-2 (2nd flight model of Meteosat Second Generation) was one of the two payloads of Ariane 5’s latest launch. The European launch vehicle lifted off from the Guiana Space Centre, Europe’s spaceport, in Kourou, French Guiana, at 19:33 local time on 21 December (23:33 CET).

The Ariane 5GS vehicle successfully delivered its two passenger payloads onto a near perfect geostationary transfer orbit. The MSG-2 satellite is now under control of ESA’s European Space Operations Centre (ESOC) in Darmstadt, Germany, under a contract with EUMETSAT. In the coming days, it will perform a series of orbital manoeuvres using its onboard propulsion system in order to circularize its orbit at geostationary altitude.

“The successful launch of the second Meteosat satellite today reinforces the cooperation between the European Space Agency (ESA) and EUMETSAT in the designing and development of a series of missions devoted to meteorology” said Volker Liebig, ESA’s Director of Earth Observation programmes.

“Two further MSG satellites, planned to be launched, will guarantee continuity of services until around 2018. MSG- 2 improves today the provision of essential data and information for operational weather forecast and sustainable development” he continued.

MSG-2 is the first of three satellites based on the same design and procured by ESA on behalf of EUMETSAT, the European weather satellite organization, founded in 1986 and now encompassing all 17 ESA member states plus Turkey. Bulgaria, Croatia, the Czech Republic, Estonia, Hungary, Iceland, Latvia, Romania, Serbia-Montenegro, Slovakia and Slovenia are also contributing states to the organisation.

A new eye to watch our weather

The MSG satellites are designed to observe the Earth in twelve spectral bands and to deliver pictures every 15 minutes in visible light, infrared and at water vapour wavelength, with a ground resolution of 1 km. In all, they are able to return 10 times more data than the satellites of the original series.

Weighing about 2 metric tons at launch, the MSGs are twice and half heavier than their predecessors, but about half of this mass is propellant for reaching the operational orbit and station-keeping for about 7 years. They keep the same drum-shaped design but at a larger scale, with a 3.22-m diameter and a height of 3.74 m.

The payload is composed of two radiometers, SEVIRI and GERB. The Spinning Enhanced Visible & Infrared Imager (SEVIRI) observes the Earth in 12 spectral bands in visible light and infrared and delivers a picture of the hemisphere every 15 minutes. This allows to follow closely the development of rapidly evolving weather phenomena like storms, blizzards and fog. Its ground resolution in visible parts of the spectrum is 1 km, in order to monitor highly localized events.

The Global Earth Radiation Budget (GERB) experiment measures the amount of solar radiation reflected into space by the Earth and atmosphere, providing vital information about global climate change.

Besides these two instruments, MSG satellites carry a comprehensive communications payload for satellite operation, data communication and user data dissemination. It also includes a Search and Rescue transponder to relay distress signals from ships, aircraft and others in peril to the emergency services.

Witnessing global climate change

Once in geostationary orbit, MSG-2 will undergo several months of in-orbit commissioning before being operational. A first picture of the Earth captured by the SEVIRI instrument should be released by late January. In summer 2006 , MSG-2 is expected to enter operational service above the Gulf of Guinea, at 0 degree of longitude.

Renamed Meteosat 9, it will replace Meteosat 8 as the primary satellite to monitor the atmosphere and the climate. Meteosat 8 will be moved to 3.4 degrees West as a back-up satellite in order to ensure continuity of service in any circumstance. In addition EUMETSAT still operates the first-generation Meteosat 5, 6 and 7 satellites with an extended coverage over the Indian Ocean.

The MSG programme was decided in 1990 as follow-on to the highly successful original Meteosat series, with the introduction of new, more powerful and more accurate sensors, for a continuous observation of Earth’s atmosphere. With two more satellites currently ordered, the MSG series should provide coverage at least through 2018. This uninterrupted monitoring lasts since the very first Meteosat satellite, which was developed and launched by ESA in 1977. The Meteosat data are a unique testimony on the evolution of the planet’s climate over nearly three decades and its consequences on our weather.

Original Source: ESA Portal

Stardust is Almost Home

Artist’s impression of Stardust returning back to Earth. Image credit: NASA/JPL Click to enlarge
NASA’s Stardust mission is nearing Earth after a 4.63 billion kilometer (2.88 billion mile) round-trip journey to return cometary and interstellar dust particles back to Earth. Scientists believe the cargo will help provide answers to fundamental questions about comets and the origins of the solar system.

The velocity of the sample return capsule, as it enters Earth’s atmosphere at 46,440 kilometers per hour (28,860 miles per hour), will be the fastest of any human-made object on record. It surpasses the record set in May 1969 during the return of the Apollo 10 command module. The capsule is scheduled to return on Jan. 15, 2006.

“Comets are some of the most informative occupants of the solar system. The more we can learn from science exploration missions like Stardust, the more we can prepare for human exploration to the moon, Mars and beyond,” said Dr. Mary Cleave, associate administrator for NASA’s Science Mission Directorate.

Several events must occur before scientists can retrieve cosmic samples from the capsule landing at the U.S. Air Force Utah Test and Training Range, southwest of Salt Lake City. Mission navigators will command the spacecraft to perform targeting maneuvers on Jan. 5 and 13. On Jan 14 at 9:57 p.m. PST (12:57 a.m. EST on Jan. 15), Stardust will release its sample return capsule. Four hours later, the capsule will enter Earth’s atmosphere 125 kilometers (410,000 feet) over the Pacific Ocean.

The capsule will release a drogue parachute at approximately 32 kilometers (105,000 feet). Once the capsule has descended to about 3 kilometers (10,000 feet), the main parachute will deploy. The capsule is scheduled to land on the range at 2:12 a.m. PST (5:12 a.m. EST).

After the capsule lands, if conditions allow, a helicopter crew will fly it to the U.S. Army Dugway Proving Ground, Utah, for initial processing. If weather does not allow helicopters to fly, special off-road vehicles will retrieve the capsule and return it to Dugway. Samples will then be moved to a special laboratory at NASA’s Johnson Space Center, Houston, where they will be preserved and studied.

“Locked within the cometary particles is unique chemical and physical information that could be the record of the formation of the planets and the materials from which they were made,” said Dr. Don Brownlee, Stardust principal investigator at the University of Washington, Seattle.

NASA expects most of the collected particles to be no more than a third of a millimeter across. Scientists will slice these particle samples into even smaller pieces for study.

NASA’s Jet Propulsion Laboratory, Pasadena, Calif. manages the Stardust mission for NASA’s Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft.

For information about the Stardust mission on the Web, visit http://www.nasa.gov/stardust .

Original Source: NASA News Release

Ariane 5 Lofts Record Payload into Orbit

The heavy-lift Ariane 5 ECA. Image credit: Arienspace. Click to enlarge
During the night of Wednesday, November 16 to Thursday, November 17, Arianespace placed two satellites into geostationary transfer orbit: the SPACEWAY 2 high-definition direct broadcast satellite for the American operator DIRECTV, and the TELKOM 2 communications satellite for the Indonesian operator PT Telekomunikasi Indonesia Tbk.

20th successful Ariane 5 launch, 10th in a row, record payload.

Today’s mission sets a new record for commercial launches: with over 8,000 kg. injected into orbit, the SPACEWAY 2 and TELKOM 2 satellites represent the heaviest dual payload ever launched.

Today, Ariane 5 is the only commercial launcher in service capable of simultaneously launching two payloads. Ariane 5 ECA offers a payload capacity of nearly 10,000 kg. into geostationary transfer orbit, giving Arianespace’s customers enhanced performance, flexibility and competitiveness through the best launch service in the world.

Today’s mission was the 20th successful launch of an Ariane 5, and the 10th successful launch in a row. One week after the successful launch of the Venus Express spacecraft by a Soyuz rocket from the Baikonur Cosmodrome, this confirms that Arianespace, with its complete family of launchers, offers the best launch solution for operators from around the world.

Original Source: Arienspace News Release

Gravity Probe B Will Tell Us If Einstein Was Right

An artist’s concept of twisted space-time around Earth. Image credit: NASA. Click to enlarge
Is Earth in a vortex of space-time?

We’ll soon know the answer: A NASA/Stanford physics experiment called Gravity Probe B (GP-B) recently finished a year of gathering science data in Earth orbit. The results, which will take another year to analyze, should reveal the shape of space-time around Earth–and, possibly, the vortex.

Time and space, according to Einstein’s theories of relativity, are woven together, forming a four-dimensional fabric called “space-time.” The tremendous mass of Earth dimples this fabric, much like a heavy person sitting in the middle of a trampoline. Gravity, says Einstein, is simply the motion of objects following the curvaceous lines of the dimple.

If Earth were stationary, that would be the end of the story. But Earth is not stationary. Our planet spins, and the spin should twist the dimple, slightly, pulling it around into a 4-dimensional swirl. This is what GP-B went to space to check

The idea behind the experiment is simple:

Put a spinning gyroscope into orbit around the Earth, with the spin axis pointed toward some distant star as a fixed reference point. Free from external forces, the gyroscope’s axis should continue pointing at the star–forever. But if space is twisted, the direction of the gyroscope’s axis should drift over time. By noting this change in direction relative to the star, the twists of space-time could be measured.

In practice, the experiment is tremendously difficult.

The four gyroscopes in GP-B are the most perfect spheres ever made by humans. These ping pong-sized balls of fused quartz and silicon are 1.5 inches across and never vary from a perfect sphere by more than 40 atomic layers. If the gyroscopes weren’t so spherical, their spin axes would wobble even without the effects of relativity.

According to calculations, the twisted space-time around Earth should cause the axes of the gyros to drift merely 0.041 arcseconds over a year. An arcsecond is 1/3600th of a degree. To measure this angle reasonably well, GP-B needed a fantastic precision of 0.0005 arcseconds. It’s like measuring the thickness of a sheet of paper held edge-on 100 miles away.

GP-B researchers invented whole new technologies to make this possible. They developed a “drag free” satellite that could brush against the outer layers of Earth’s atmosphere without disturbing the gyros. They figured out how to keep Earth’s penetrating magnetic field out of the spacecraft. And they concocted a device to measure the spin of a gyro–without touching the gyro.

Pulling off the experiment was an exceptional challenge. A lot of time and money was on the line, but the GP-B scientists appear to have done it.

“There were not any major surprises” in the experiment’s performance, says physics professor Francis Everitt, the Principal Investigator for GP-B at Stanford University. Now that data-taking is complete, he says the mood among the GP-B scientists is “a lot of enthusiasm, and a realization also that a lot of grinding hard work is ahead of us.”

A careful, thorough analysis of the data is underway. The scientists will do it in three stages, Everitt explains. First, they will look at the data from each day of the year-long experiment, checking for irregularities. Next they’ll break the data into roughly month-long chunks, and finally they’ll look at the whole year. By doing it this way, the scientists should be able to find any problems that a more simple analysis might miss.

Eventually scientists around the world will scrutinize the data. Says Everitt, “we want our sternest critics to be us.”

The stakes are high. If they detect the vortex, precisely as expected, it simply means that Einstein was right, again. But what if they don’t? There might be a flaw in Einstein’s theory, a tiny discrepancy that heralds a revolution in physics.

First, though, there are a lot of data to analyze. Stay tuned.

Original Source: NASA News Release

Cryosat Launch Fails

Cryosat launch. It crashed back to Earth shortly after. Image credit: ESA. Click to enlarge.
Mr Yuri Bakhvalov, First Deputy Director General of the Khrunichev Space Centre on behalf of the Russian State Commission officially confirmed that the launch of CryoSat ended in a failure due to an anomaly in the launch sequence and expressed his regret to ESA and all partners involved.

Preliminary analysis of the telemetry data indicates that the first stage performed nominally. The second stage performed nominally until main engine cut-off was to occur. Due to a missing command from the onboard flight control system the main engine continued to operate until depletion of the remaining fuel.

As a consequence, the separation of the second stage from upper stage did not occur. Thus, the combined stack of the two stages and the CryoSat satellite fell into the nominal drop zone north of Greenland close to the North Pole into high seas with no consequences to populated areas.

An investigating commission by the Russian State authorities has been established to further analyze the reasons for the failure, results are expected within the next weeks. This commission will work in close cooperation with a failure investigation board consisting of Eurockot, ESA and Khrunichev representatives.

This information is released at the same time by Eurockot and ESA.

Original Source: ESA News Release

Gravity Probe B Wraps Up Observations

Artist illustration of the Gravity Probe B satellite in orbit. Image credit: NASA/Stanford. Click to enlarge.
Almost 90 years after Albert Einstein first postulated his general theory of relativity, scientists have finished collecting data to put it to a new, different kind of experimental test.

NASA’s Gravity Probe B satellite has been orbiting the Earth for more than 17 months. It used four ultra-precise gyroscopes to generate the data required for this unprecedented test. Fifty weeks worth of data has been downloaded from the spacecraft and relayed to computers in the Mission Operations Center at Stanford University, Stanford, Calif. Scientists have begun the painstaking task of data analysis and validation, which is expected to take approximately one year.

“This has been a tremendous mission for all of us,” said Francis Everitt, Gravity Probe B principal investigator at Stanford. “With all the data gathered, we are proceeding deliberately to ensure everything is checked and re-checked. NASA and Stanford can be proud of what has been achieved so far.”

Launched on April 20, 2004, from Vandenberg Air Force Base, Calif., Gravity Probe B has been using four spherical gyroscopes to precisely measure two extraordinary effects predicted by Einstein’s theory. One is the geodetic effect, the amount by which the Earth warps the local space time in which it resides. The other, called frame-dragging, is the amount by which the rotating Earth drags local space time around with it.

“The completion of the GP-B mission is the culmination of years of hard work, training and preparation by the GP-B team,” said Tony Lyons, NASA GP-B program manager from NASA?s Marshall Space Flight Center in Huntsville, Ala.

“We are proud to have been associated with this extremely significant mission,” said Bob Schultz, Lockheed Martin’s Gravity Probe B program manager. “Working with Stanford and NASA, we formed a powerful team to develop the challenging technologies needed to take a giant step forward in helping understand Einstein’s theory of general relativity.”

The Marshall manages the Gravity Probe B program. Stanford conceived the experiment and is NASA’s prime contractor for the mission. Stanford was responsible for the design and integration of the science instruments and mission operations. The university has the lead for data analysis. Lockheed Martin Space Systems Company designed, integrated and tested the space vehicle and built some major payload components.

Original Source: NASA News Release

Future Titan Mission Shield Blasted By Radiation

Solar power heats NASA space shield material. Image credit: Bill Congdon, Applied Research Associates. Click to enlarge
For the last two years, tests have been conducted at Sandia National Laboratories? National Solar Thermal Test Facility to see how materials used for NASA?s future planetary exploration missions can withstand severe radiant heating.

The tests apply heat equivalent to 1,500 suns to spacecraft shields called Advanced Charring Ablators. The ablators protect spacecraft entering atmospheres at hypersonic speeds.

The test facility includes a 200-ft. ?solar tower? surrounded by by a field of hundreds of sun-tracking mirror arrays called heliostats. The heliostats direct sunlight to the top of the tower where the test objects are affixed.

Under a work agreement, researchers at Sandia and Applied Research Associates, Inc. are conducting the tests for NASA Marshall?s In-Space Propulsion/Aerocapture Program. The R&D effort is tied to NASA?s plan for a future Titan mission with an orbiter and lander. Titan is Saturn?s largest moon.

The tests are led by Sandia solar tower expert Cheryl Ghanbari and Bill Congdon, project principal investigator for Applied Research Associates, Inc.

Solar power heats NASA space shield material. The tests apply heat equivalent to 1,500 suns to spacecraft shields. (Photo courtesy of Bill Congdon, Applied Research Associates, Inc.)
Download 300dpi JPEG image, ?solar-heat.jpg,? 376K (Media are welcome to download/publish this image with related news stories.)The tests are designed to simulate atmospheric heating of spacecraft that enter Titan, including low levels of convective heating combined with relatively high levels of thermal radiation.

The primary ablator candidates for the Titan mission are low-density silicones and phenolics, all under 20 pounds-per-cubic-foot density.

To date, more than 100 five-inch diameter samples have been tested in the solar environment inside the tower?s wind tunnel using a large quartz window.

Congdon says because of Titan?s relatively high radiation environment, some initial concerns had to be put to rest through testing. He says radiation might penetrate in-depth within the ablator, causing an increased ?apparent? thermal conductivity and degrading insulation performance.

?Radiation could also generate high-pressure gasses within the ablator leading to spallation,? Congdon says.

?We have been testing at the solar tower to see how the candidate Titan materials can withstand the expected range of heating conditions,? Ghanbari says. ?Titan has a nitrogen-rich atmosphere and nitrogen is used in the tests to similarly reduce ablator oxidation, while energy from the sun-tracking heliostats is focused on the samples.?

Congdon says ground tests are necessary to understand and model surface ablation of the materials that will be severely heated during Titan entry.

During thermal radiation testing conducted in the solar tower, all of these concerns were addressed and found not to be a problem for the ablators of interest.

About the tests

The National Solar Thermal Test Facility consists of an eight-acre field of 220 solar-collection heliostats and a 200-ft.-tall tower that receives the collected energy at one of several test bays. A single heliostat includes 25 mirrors that are each four feet square. Total collection area of 220 heliostats is 88,000-square feet.

Because the heliostats are individually computer controlled, test radiation can be a shaped pulse as well as a square wave in terms of intensity vs. time, says Ghanbari.

Test samples are mounted high in the receiver tower, and the heliostats direct the sunlight upward to irradiate the sample surface. The samples are mounted in a water-cooled copper plate inside the wind tunnel with a quartz window that allows entry of the concentrated radiation.

Exposure is controlled by a fast-moving shutter and by pre-programmed heliostat movement. Radiation flux is calibrated before and after each test by a radiometer installed to occupy the same position as the test sample. Cooling effects from imposed surface flows are calibrated via a flat-plate slug calorimeter.

The materials are subjected to square pulse environments at flux levels of 100 and 150 W/cm2 for time periods that far exceed predicted flight durations for such high heating. They are also tested to ?exact? flux vs. time environments (simulating actual flight conditions) using programmed heliostat focusing at the solar tower facility.

The material samples are installed in the tower?s wind tunnel and exposed to the solar beam at flux levels up to 150 W/cm2, which is approximately 1,500 times the intensity of the sun on earth on a clear day. During exposure, air blows past the sample at about mach 0.3 with a high-speed nitrogen sub-layer close to the sample surface.

Ghanbari says tests can be conducted only during about four hours midday bracketing solar noon. Haze, clouds, and high winds that affect the heliostats can degrade test conditions.

Current results

?All of the candidate materials showed no spallation and very good thermal performance to these imposed environments,? Congdon says. Recently, five 12-inch by 12-inch panel samples were tested on top of the tower. Up to 20 additional 12-inch panels will be tested late in the summer followed by testing of 2-foot by 2-foot panels later in the year.

Additional tests for convective heating have been conducted on identical material samples at the Interaction Heating Facility (IHF) at NASA?s Ames Research Center.

Origianl Source: Sandia National Labs

NASA’s Prototype Solar Sail Inflates Perfectly

20-meter solar sail. Image credit: NASA/MSFC Click to enlarge
NASA has reached a milestone in the testing of solar sails — a unique propulsion technology that will use sunlight to propel vehicles through space. Engineers have successfully deployed a 20-meter solar sail system that uses an inflatable boom deployment design.

L’Garde, Inc. of Tustin, Calif., deployed the system at the Space Power Facility — the world’s largest space environment simulation chamber — at NASA Glenn Research Center’s Plum Brook Station in Sandusky, Ohio. L’Garde is a technology development contractor for the In-Space Propulsion Technology Office at NASA’s Marshall Space Flight Center in Huntsville, Ala. NASA’s Langley Research Center in Hampton, Va., provided instrumentation and test support for the tests.

Red lights help illuminate the four, outstretched triangular sail quadrants in the chamber. The sail material is supported by an inflatable boom system designed to unfold and become rigid in the space environment. The sail and boom system is extended via remote control from a central stowage container about the size of a suitcase.

L’Garde began testing its sail system at Plum Brook in June. The test series lasted 30 days.

Solar sail technologies use energy from the Sun to power a spacecraft’s journey through space. The technology bounces sunlight off giant, reflective sails made of lightweight material 40-to-100-times thinner than a piece of writing paper. The continuous sunlight pressure provides sufficient thrust to perform maneuvers, such as hovering at a fixed point in space or rotating the vehicle’s plane of orbit. Such a maneuver would require a significant amount of propellant for conventional rocket systems.

Because the Sun provides the necessary propulsive energy, solar sails require no onboard propellant, thus increasing the range of mobility or the capability to hover at a fixed point for longer periods of time.

Solar sail technology was selected for development in August 2002 by NASA’s Science Mission Directorate in Washington. Along with sail system design projects, the Marshall Center and NASA’s Jet Propulsion Laboratory in Pasadena, Calif., are collaborating to investigate the effects of the space environment on advanced solar sail materials. These are just three of a number of efforts undertaken by NASA Centers, industry and academia to develop solar sail technology.

Solar sail technology is being developed by the In-Space Propulsion Technology Program, managed by NASA’s Science Mission Directorate and implemented by the In-Space Propulsion Technology Office at Marshall. The program’s objective is to develop in-space propulsion technologies that can enable or benefit near- or mid-term NASA space science missions by significantly reducing cost, mass and travel times.

For more information about solar sail propulsion, visit:
http://www.inspacepropulsion.com

For more information about L’Garde, Inc. and its solar sail system, visit:
http://www.lgarde.com/

Original Source: NASA News Release

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.”

Voyager 1 Enters the Heliosheath

Artist illustration of the position of the twin Voyager spacecraft. Image credit: NASA/JPL. Click to enlarge.
NASA’s Voyager 1 spacecraft has entered the solar system’s final frontier. It is entering a vast, turbulent expanse where the Sun’s influence ends and the solar wind crashes into the thin gas between stars.

“Voyager 1 has entered the final lap on its race to the edge of interstellar space,” said Dr. Edward Stone, Voyager project scientist at the California Institute of Technology in Pasadena. Caltech manages NASA’s Jet Propulsion Laboratory in Pasadena, which built and operates Voyager 1 and its twin, Voyager 2.

In November 2003, the Voyager team announced it was seeing events unlike any in the mission’s then 26-year history. The team believed the unusual events indicated Voyager 1 was approaching a strange region of space, likely the beginning of this new frontier called the termination shock region. There was considerable controversy over whether Voyager 1 had indeed encountered the termination shock or was just getting close.

The termination shock is where the solar wind, a thin stream of electrically charged gas blowing continuously outward from the Sun, is slowed by pressure from gas between the stars. At the termination shock, the solar wind slows abruptly from a speed that ranges from 700,000 to 1.5 million miles per hour and becomes denser and hotter. The consensus of the team is that Voyager 1, at approximately 8.7 billion miles from the Sun, has at last entered the heliosheath, the region beyond the termination shock.

Predicting the location of the termination shock was hard, because the precise conditions in interstellar space are unknown. Also, changes in the speed and pressure of the solar wind cause the termination shock to expand, contract and ripple.

The most persuasive evidence that Voyager 1 crossed the termination shock is its measurement of a sudden increase in the strength of the magnetic field carried by the solar wind, combined with an inferred decrease in its speed. This happens whenever the solar wind slows down.

In December 2004, the Voyager 1 dual magnetometers observed the magnetic field strength suddenly increasing by a factor of approximately 2-1/2, as expected when the solar wind slows down. The magnetic field has remained at these high levels since December. NASA’s Goddard Space Flight Center, Greenbelt, Md., built the magnetometers.

Voyager 1 also observed an increase in the number of high-speed electrically charged electrons and ions and a burst of plasma wave noise before the shock. This would be expected if Voyager 1 passed the termination shock. The shock naturally accelerates electrically charged particles that bounce back and forth between the fast and slow winds on opposite sides of the shock, and these particles can generate plasma waves.

“Voyager’s observations over the past few years show the termination shock is far more complicated than anyone thought,” said Dr. Eric Christian, Discipline Scientist for the Sun-Solar System Connection research program at NASA Headquarters, Washington.

The result is being presented today at a press conference in the Morial Convention Center, New Orleans, during the 2005 Joint Assembly meeting of Earth and space science organizations.

For their original missions to Jupiter and Saturn, Voyager 1 and sister spacecraft Voyager 2 were destined for regions of space far from the Sun where solar panels would not be feasible, so each was equipped with three radioisotope thermoelectric generators to produce electrical power for the spacecraft systems and instruments. Still operating in remote, cold and dark conditions 27 years later, the Voyagers owe their longevity to these Department of Energy-provided generators, which produce electricity from the heat generated by the natural decay of plutonium dioxide.

Original Source: NASA/JPL News Release