Posted on by Fraser Cain

Key Part Redesigned for Shuttle’s Return to Flight

NASA is moving ahead with plans to redesign a part of the Space Shuttle external fuel tank that investigators believe played a critical role in the Space Shuttle Columbia accident. The Space Shuttle program will soon begin manufacturing and installing an improved bipod fitting, which connects the external fuel tank to the Shuttle during launch.

A Critical Design Review Board of NASA managers, engineers and aerospace contractors last month approved the new design, a significant milestone in the effort to return the Shuttle to safe flight. The approval allows workers to begin incorporating the new fitting on External Tank No. 120, the tank slated for flight on the next Shuttle mission, designated STS-114.

Investigators believe that during Columbia’s launch in January 2003, insulating foam from the bipod area fell off the external tank and damaged the left wing of the Space Shuttle. The new design addresses the Columbia Accident Investigation Board recommendation to reduce the risk to the Shuttle from falling debris during liftoff. It eliminates the foam covering from the bipod fitting and replaces it with four rod-shaped heaters. The heaters will serve the same primary function as the foam, preventing ice buildup on the tank’s bipod fittings.

“This is a fix that really gets to the root of the technical problems that caused the loss of Columbia,” said Michael Kostelnik, NASA’s Deputy Associate Administrator for International Space Station and Space Shuttle Programs. “By eliminating this debris source, as well as potential debris from other areas, we are making the Shuttle a safer spacecraft.”

The External Tank Project Office at NASA’s Marshall Space Flight Center, Huntsville, Ala., first began developing redesign concepts for the bipod fitting after insulating foam from the left bipod ramp area detached during the October 2002 launch of Space Shuttle Atlantis.

The newly designed heaters will be placed below the fitting, in covers made of a strong alloy composed of nickel, chromium and iron. They will sit on top of a copper plate sandwiched between the fitting and a hard, dense material that separates the heater from the tank.

The design will be retrofitted on the 11 existing tanks and incorporated into the manufacture of all new tanks. Lockheed Martin Space Systems will do the work at NASA’s Michoud Assembly Facility in New Orleans. Delivery of the retrofitted tanks to NASA’s Kennedy Space Center, Florida, is expected in October.

For still photos on the Internet of the redesigned bipod fitting, visit:

http://www.nasa.gov/returntoflight

Video b-roll of the new bipod will air on NASA Television during the Video File segment starting at noon EDT today. Beginning July 24, NASA Television will be seen in the continental United States on AMC-6, at 72 degrees west longitude, Transponder 9, 3880 MHz, vertical polarization, audio at 6.8 MHz. If you live in Alaska or Hawaii, NASA TV will now be seen on AMC-7, at 137 degrees west longitude, Transponder 18, at 4060 MHz, vertical polarization, audio at 6.8 MHz.

For information about NASA TV, visit:

http://www.nasa.gov/ntv

More information on NASA’s human space flight programs is available at:

http://www.nasa.gov

Original Source: NASA News Release

Posted on by Fraser Cain

Crescent Titan

Following its first flyby of Titan, Cassini gazed back at the smog-enshrouded moon?s receding crescent. This natural color view was seen by the spacecraft about one day after closest approach. The slight bluish purpose glow of Titan?s haze is visible along the limb.

The superimposed coordinate system grid in the accompanying image at right illustrates the geographical regions of the moon that are illuminated and visible, as well as the orientation of Titan ? lines of longitude converge on the South Pole near the moon?s eastern limb. The yellow curve marks the position of the boundary between day and night on Titan.

Images taken through blue, green and red filters were combined to create this natural color view. The image were obtained using the wide angle camera on July 3, 2004, from a distance of about 790,000 kilometers (491,000 miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 115 degrees. The image scale is 47 kilometers (29 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Original Source: CICLOPS News Release

Posted on by Fraser Cain

Neutrino Mass Linked to Dark Energy

Two of the biggest physics breakthroughs during the last decade are the discovery that wispy subatomic particles called neutrinos actually have a small amount of mass and the detection that the expansion of the universe is actually picking up speed.

Now three University of Washington physicists are suggesting the two discoveries are integrally linked through one of the strangest features of the universe, dark energy, a linkage they say could be caused by a previously unrecognized subatomic particle they call the “acceleron.”

Dark energy was negligible in the early universe, but now it accounts for about 70 percent of the cosmos. Understanding the phenomenon could help to explain why someday, long in the future, the universe will expand so much that no other stars or galaxies will be visible in our night sky, and ultimately it could help scientists discern whether expansion of the universe will go on indefinitely.

In this new theory, neutrinos are influenced by a new force resulting from their interactions with accelerons. Dark energy results as the universe tries to pull neutrinos apart, yielding a tension like that in stretched rubber band, said Ann Nelson, a UW physics professor. That tension fuels the expansion of the universe, she said.

Neutrinos are created by the trillions in the nuclear furnaces of stars such as our sun. They stream through the universe, and billions pass through all matter, including people, every second. Besides a minuscule mass, they have no electrical charge, which means they interact very little, if at all, with the materials they pass through.

But the interaction between accelerons and other matter is even weaker, Nelson said, which is why those particles have not yet been seen by sophisticated detectors. However, in the new theory, accelerons exhibit a force that can influence neutrinos, a force she believes can be detected by a variety of neutrino experiments already operating around the world.

“There are many models of dark energy, but the tests are mostly limited to cosmology, in particular measuring the rate of expansion of the universe. Because this involves observing very distant objects, it is very difficult to make such a measurement precisely,” Nelson said.

“This is the only model that gives us some meaningful way to do experiments on earth to find the force that gives rise to dark energy. We can do this using existing neutrino experiments.”

The new theory is advanced in a paper by Nelson; David Kaplan, also a UW physics professor; and Neal Weiner, a UW research associate in physics. Their work, supported in part by a grant from the U.S. Department of Energy, is detailed in a paper accepted for publication in an upcoming issue of Physical Review Letters, a journal of the American Physical Society.

The researchers say a neutrino’s mass can actually change according to the environment through which it is passing, in the same way the appearance of light changes depending on whether it’s traveling through air, water or a prism. That means that neutrino detectors can come up with somewhat different findings depending on where they are and what surrounds them.

But if neutrinos are a component of dark energy, that suggests the existence of a force that would reconcile anomalies among the various experiments, Nelson said. The existence of that force, made up of both neutrinos and accelerons, will continue to fuel the expansion of the universe, she said.

Physicists have pursued evidence that could tell whether the universe will continue to expand indefinitely or come to an abrupt halt and collapse on itself in a so-called “big crunch.” While the new theory doesn’t prescribe a “big crunch,” Nelson said, it does mean that at some point the expansion will stop getting faster.

“In our theory, eventually the neutrinos would get too far apart and become too massive to be influenced by the effect of dark energy any more, so the acceleration of the expansion would have to stop,” she said. “The universe could continue to expand, but at an ever-decreasing rate.”

Original Source: University of Washington News Release

Posted on by Fraser Cain

Astronauts Prepare for Third Spacewalk

The International Space Station’s Expedition 9 crewmembers are now past the halfway point of their six-month mission. This week, they prepared for a third spacewalk and joined the world in observing the 35th anniversary of the first landing of humans on the moon.

July 19 was the midpoint of the flight for ISS Commander Gennady Padalka and Flight Engineer Mike Fincke, who launched Apr. 19 and are targeted to return Oct. 19. On Monday Fincke spoke with Charles Gibson of ABC-TV’s “Good Morning, America” about the birth of his daughter, Tarali, in June while he was in space. Fincke’s wife and children joined the discussion from Houston.

This week the crew continued packing unneeded equipment and trash in the Progress vehicle, scheduled to undock July 30. Undocking the Progress from Zvezda’s aft docking port will clear the area for the next spacewalk, targeted for Aug. 3. Wearing Russian spacesuits and exiting from the Pirs Docking Compartment, Padalka and Fincke are to install retroreflectors and communications equipment needed for the docking of the Automated Transfer Vehicle, a European Space Agency cargo spacecraft scheduled to make its first flight next year. Yesterday, Padalka and Fincke maneuvered the Station’s Canadarm2 into position so its cameras can view the spacewalk, and today they wrapped up a thorough review of the spacewalk timeline with specialists in Moscow.

Fincke and Padalka also continued their support this week of an experiment that looks at the interactions between the crew and the ground teams. This experiment involves a questionnaire on a laptop computer, which the crew and members of their ground support team complete once a week. The data is being used to examine issues involving tension, cohesion and leadership roles in both the crewmembers and their support team. The information gained will lead to improved training and in-flight support of future space crews.

As part of Fincke’s Saturday Afternoon Science, he conducted another session of the Educational Payload Operations or EPO. This EPO activity demonstrated what crewmembers can observe about pollution and the environmental problems on Earth. Fincke showed the window where he observes the Earth, and described what types of pollution can be seen — such as air pollution in urban areas, smoke from wildfires, deforestation and strip mining.

The activity was videotaped and will be used later in classrooms and NASA educational products. EPO is an education payload designed to support the NASA Mission to inspire the next generation of explorers.

Meanwhile, flight controllers in Houston are continuing to investigate why two U.S. spacesuits are not providing the proper cooling. This week, Fincke conducted troubleshooting of a motor in the water pump of one of the spacesuits as engineers on the ground monitored. An analysis of photos and video from that work is underway. Two spare water pumps will be launched in the next Progress supply ship, due to lift off Aug. 11 from the Baikonur Cosmodrome in Kazakhstan.

The failure of a computer on the Station’s inactive starboard thermal radiator on Monday has no significant impact on current operations. The radiator is not in use in the present Station configuration, although the computer had assisted flight controllers with monitoring of temperatures and pressures of the unused equipment. The radiator is not scheduled to be used until several missions after the Space Shuttle’s return to flight.

Tuesday, Padalka and Fincke celebrated the anniversary of the Apollo 11 moon landing and discussed the past, present and future of space exploration — and the role to be played by the International Space Station in future exploration — during in an interview with CBS News.

For information about NASA and agency missions on the Internet, visit:

http://www.nasa.gov

Information about crew activities on the Space Station, future launch dates and Station sighting opportunities from Earth, is available on the Internet at:

http://spaceflight.nasa.gov/

Details about Station science operations are available on an Internet site administered by the Payload Operations Center at NASA’s Marshall Space Flight Center in Huntsville, Ala., at:

http://scipoc.msfc.nasa.gov/

Original Source: NASA News Release

Posted on by Fraser Cain

Some of the Hazards in Space

Space is one of the most extreme environments imaginable. Above the insulating atmosphere of the Earth, spacecraft are subjected to extremes of temperature, both hot and cold, and a significantly increased threat of radiation damage.

The first extreme condition a spacecraft has to deal with is that of launch. The rocket that places the spacecraft into orbit will also shake it violently and batter it with extremely loud sound waves.

Either of these phenomena can shatter delicate pieces of equipment and so engineers always build a thermal and structural model of the spacecraft and test it. They simulate the conditions of launch using the vibration table and acoustic chamber at ESA’s European Space Technology Centre (ESTEC) in The Netherlands.

Temperatures in space can range from the extremely cold, hundreds of degrees below freezing, to many hundreds of degrees above ? especially if a spacecraft ventures close to the Sun.

Although there is no air in space, energy is carried by radiation, usually coming from the Sun, that causes heating when it is absorbed by spacecraft, planets or other celestial bodies.

Depending on where in space they intend a vehicle to operate, engineers build in either cooling systems or insulators.

However, in the case of ESA’s comet-chaser Rosetta, the spacecraft must first venture into the heat of the inner Solar System, before heading away into the freezing outer Solar System.

Engineers designed a system of ‘louvres’ that fit over the spacecraft’s radiator panels. When Rosetta is in the inner Solar System, the louvres swing open, allowing the radiators to expel excess heat into space.

Later, in the outer Solar System, the louvres shut, helping to retain heat inside. Ensuring that integrated circuits and computers can work in the radiation environment of space requires the shielding of sensitive electronic equipment.

Radiation in space can be split into ‘trapped’ and ‘transient’ types. The trapped particles are the subatomic particles, mainly protons and electrons, trapped by Earth’s magnetic field which creates the so-called Van Allen radiation belts around our planet.

The Cluster quartet of spacecraft are designed to work in and investigate this region of space.

The transient radiation is mainly composed of protons and cosmic rays that constantly stream through space and are enhanced during the magnetic storms on the Sun known as ‘solar flares’.

When this radiation collides with electronic circuits, they can change the contents of memory cells, cause spurious currents to flow around the craft or even burn out computer chips.

Building integrated circuits that resist the effects of radiation is known as ‘space hardening’. Usually this involves redesigning the chips so that they are shielded in some way from the harmful radiation. Another approach is to detect the errors produced by space radiation and correct them.

Meteor showers can also damage spacecraft. The little dust particles that cause us to see ‘shooting stars’ travel through space at several kilometres per second and can have the effect of ‘sand blasting’ large arrays of vital solar panels.

During a storm of the Leonids, for example, scientists made the Hubble Space Telescope turn so that its solar panels presented the smallest surface area to the incoming meteors.

Original Source: ESA News Release

Posted on by Fraser Cain

Fractured Crater on Mars

This perspective image of a fractured crater near Valles Marineris on Mars was obtained by the High Resolution Stereo Camera (HRSC) on board the ESA Mars Express spacecraft.

The image was taken during orbit 61 in January 2004 with a resolution of 12. 5 metres per pixel. It shows part of a cratered landscape to the north of the Valles Marineris, at 0.6? S latitude and 309? E longitude, with this crater having a fractured base.

This crater has a rim diameter of 27.5 kilometres and is about 800 metres deep. It is not known yet how these fractures are generated. On Earth, polygonal fractures may occur in contracting material, which breaks at weak zones. For example, we may see this appearing in cooled lava, dried clay or frozen ground.

Original Source: ESA News Release

Posted on by Fraser Cain

Closer to Titan

About a day after entering orbit around Saturn, Cassini sped silently past Titan, passing some 339,000 kilometers (210,600 miles) above the moon?s south polar region. This natural color image represents Cassini?s view only about two hours after closest approach to the moon.

The superimposed coordinate system grid in the accompanying image at right illustrates the geographical regions of the moon that are illuminated and visible, as well as the orientation of Titan ? lines of longitude converge on the South Pole above center in the image. The yellow curve marks the position of the boundary between day and night on Titan.

Images taken through blue, green and red filters were combined to create this natural color view. The images were obtained using the wide angle camera on July 2, 2004, from a distance of about 347,000 kilometers (216,000 miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 62 degrees. This view is an improvement in resolution of nearly a factor of four over the previously released natural color view of Titan (PIA 06081). The image scale is 21 kilometers (13 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Original Source: CICLOPS News Release

Posted on by Fraser Cain

SMART-1’s View of the Middle East

Now more than 100 000 kilometres away from Earth, ESA’s Moon-bound spacecraft SMART-1 looked back at Earth and returned this planetary perspective of the Middle East and Mediterranean Sea.

‘Smart’ usage of the solar-electric propulsion system (the ion engine) has saved a lot of fuel and the spacecraft will get to the Moon earlier than expected.

Almost 20 kilograms of the xenon fuel could be saved out of the original 84 kilograms, which could then be used to get closer to the Moon than planned, to within distances of between 300 and 3000 kilometres. This will give a coverage of the lunar surface at higher resolution and sensitivity.

Original Source: ESA News Release

Posted on by Fraser Cain

Get Ready for the Perseids

Image credit: ESA
The annual Perseid meteor shower is coming, and astronomers say it could be unusually good this year.

The shower begins gently in mid-July when Earth enters the edge of a cloud of debris from Comet Swift-Tuttle.

Dust-sized particles will hit our atmosphere and appear to streak across the night sky. At first there will be just a few meteors each night, but then the rate will build. The Perseids are visible between 23 July and 22 August but, by 12 August, at the peak of the shower, skywatchers can expect to see possibly 80-100 meteors per hour if skies are clear.

This is a good year for Perseids for two reasons. First, the Moon is new in mid-August, so moonlight will not spoil the show as much as it would have done last year, had the sky been clear! Second, in addition to the usual shower on 12 August, there might be an extra show of meteors late in the evening of 11 August caused by a ?filament? of dust drifting across Earth’s orbit for the first time.

This filament, like all the dust in the Perseid cloud, again comes from Comet Swift-Tuttle. The difference is, the filament is relatively young. It ?boiled? off the comet in 1862. Other dust in the cloud is older (perhaps thousands of years old), more dispersed, and responsible for the month-long shower that peaks on 12 August. The filament will eventually disperse, too, but for now it retains some of its original ribbon shape.

According to current predictions, Earth will move through the filament on Wednesday, 11 August at 23:00 CEST. This will produce a surge of mostly faint meteors over Europe and Asia. Because of the way Comet Swift-Tuttle?s orbit is tilted, its dust falls on Earth’s northern hemisphere. Meteors appear to stream out of the constellation Perseus, which is barely visible south of the equator.

Later that night and into the early morning hours of Thursday, 12 August, observers will see the ?traditional? Perseid peak caused by the older dust from Swift-Tuttle. The best time to look for these traditional Perseids is during the hours before dawn on Thursday.

How to observe the Perseids
The best way to observe them is to look towards the northeast after dark. They appear to originate from the constellation of Perseus which at midnight lies just below the easily recognisable ‘W’ of Cassiopeia.

Try looking around 22:00-23:00 CEST on Wednesday, when Perseus is hanging low in the eastern sky. You won’t see many meteors then, but the ones you do see could be memorable. On Thursday morning, the highest frequency of meteors is likely just before dawn.

Original Source: ESA News Release

Posted on by Fraser Cain

China Launches Second Double Star

Yesterday, 25 July at 09:05 CEST (15:05 local time) the Chinese National Space Administration successfully launched Tan Ce 2, the second of the Double Star science satellites. This marks the latest important milestone in the scientific collaboration between China and the European Space Agency.

Tan Ce (“Explorer”) 2 was launched from the Taiyuan spaceport west of Beijing (Zhangye province) using a Long March 2C rocket. The launch, initially scheduled for today 26 July, took place one day earlier in order to avoid adverse weather conditions expected in the days to come. The spacecraft will join Tan Ce 1, which was launched on 29 December 2003, to complete the Double Star configuration.

About 8 hours after launch the two solid booms holding the magnetometers were successfully deployed. In the next few weeks, all spacecraft sub-systems will be checked out and the commissioning of the on-board scientific instrument will follow.

Double Star will operate alongside ESA?s quartet of Cluster satellites to closely study the interaction between the solar wind and the Earth?s magnetic field. Together, these missions will provide the most detailed view to date. TC-1 is already returning a wealth of scientific data. Back in January, both missions tracked a coronal mass ejection from the Sun and gathered valuable data about the Earth’s bow shock.

Tan Ce 2 reached its nominal orbit, with perigee at 682 km, apogee at 38279 km and inclination of 90.1 deg. The positions and orbit of the Double Star satellites have been carefully defined to enable exploration of the magnetosphere on a larger scale than is possible with Cluster alone. One example of this coordinated activity is the study of the substorms that produce aurorae.

The exact region where these emissions of brightness form is still unclear, but the simultaneous high-resolution measurements combined under these two missions are expected to provide an answer.

ESA is contributing eight scientific instruments to the mission, seven of which are Cluster-derived units.

These are the first ever European experiments to fly on a Chinese satellite. ESA will also be providing ground segment support, four hours each day, via its Villafranca satellite tracking station in Spain.

Scientific cooperation between China and ESA goes back quite a long way. A first Agreement signed back in 1980 facilitated the exchange of scientific information. Thirteen years later, the collaboration focused on a specific mission, Cluster, to study the Earth’s magnetosphere.

Then, in 1997, came a big step forward. The CNSA invited ESA to participate in the Double Star dual-satellite mission to study the Earth?s magnetic field, from a perspective different but complementary to Cluster’s. The Agreement to carry out this joint mission was signed on 9 July 2001 by ESA?s then Director General Antonio Rodot? and CNSA Administrator Luan Enjie.

For Professor David Southwood, ESA?s Science Programme Director: ?Today?s successful launch marks the culmination of these joint efforts and a further important step forward in this historic collaboration between China and Europe.?

Original Source: ESA News Release