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Scifi and Fantasy Forum: Speculation: Space exploration New and Tidbits
Space exploration New and Tidbits
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Posted By:  Nomad May 29, 2003 - 08:53 am |       | SIMONE: Europe's Plan to Explore Near Earth Objects
A handful of small, asteroid-bound satellites could one day help protect our planet from space rocks careless enough to cross paths with Earth as they wander through the Solar System.
At present, researchers with the European Space Agency (ESA) are evaluating plans to send a five-craft fleet to nearby asteroids and other objects to learn more about their size, shape and inevitable path through our planet's neighborhood. The hope is to develop a better understanding of these rocky neighbors and prepare for the off chance one ends up heading straight for us.
"Ultimately, this is all driving toward identifying any future physical impacts," said the project's science leader Simon Green during a telephone interview. Green is a researcher the Planetary and Space Sciences Research Institute at Open University in the United Kingdom, which is partnering with the technology group QinetiQ on SIMONE. "You need to learn as much about [near-earth objects] as you can in order to identify one that might hit."
SIMONE
The project dubbed the Smallsat Intercept Missions to Objects Near Earth (SIMONE), is one of six low-cost missions under development by the ESA earlier this year to study space rocks.
With SIMONE, scientists plan to launch five microsatellites into space, each headed to a different asteroid. The cube-shaped probes measure about three feet (one meter) per side and weigh about 264 pounds (120 kilograms).
Once in space, a pair of solar arrays should unfold like wings to generate the electricity needed to run an ion engine, a propulsion system that uses electrically charged particles to push a craft through space. NASA used the propulsion method in its Deep Space 1 mission.
"It's a technology that has been around awhile," said Andrés Gálvez, head of ESA's Advanced Concepts Team, of the ion drive. "But SIMONE would be the first time a satellite this small has carried one."
Ion engines are a wonder when it comes to spacecraft fuel efficiently because they require less fuel than conventional engines, which is exactly why they are planned for the SIMONE project, Gálvez told SPACE.com. Electricity from the SIMONE's solar panels is expected to ionize xenon gas carried in a small donut-shaped tank onboard each of the five probes, allowing the craft enough power to reach, and stay with, near-earth asteroids.
"Each [SIMONE probe] is a stand alone craft," Green said. "So for the sort of budget you'd expect for one large stand alone machine, we get five."
ESA researchers estimate SIMONE to cost around $160 million Euro (about $186 million USD) for all five satellites. That includes each SIMONE payload of a multispectral camera for imaging, an x-ray spectrometer to determine an asteroid's composition, a radio science experiment to measure mass, an infrared spectrometer to seek out any minerals and surface details and a laser altimeter to take topographical measurements.
"There's quite a lot of clever instruments packed aboard these things," Green said.
Crossing paths with asteroids
The Earth is no stranger to impacts by otherworldly objects. Scientists believe an object the size of a small city slammed into our planet 65 million years ago and led to the extinction of dinosaurs and a crater we now call Chicxulub in the Yucatan Peninsula.
While that impact was huge, even smaller space rocks can cause devastating effects. In June of 1908, a 200-foot wide (60-meter) asteroid exploded near Russia's Tunguska River in Siberia. The explosion released about 10 megatons of energy, about 500 times that of the atomic bomb dropped on Hiroshima, and flattened the forest for a diameter of 30 miles (50 kilometers).
"We really don't known much about them," Gálvez said of the smaller asteroids that swing by Earth. "Not even how many there are."
NASA researchers estimate that there are between 1,000 and 1,500 asteroids about a half-mile (1 kilometer) in diameter near Earth to worry about. About 640 of them have been found and NASA hopes to have cataloged the bulk of them by 2008.
But some researchers think that looking for large, kilometer-sized space rocks, which impact the planet about once every 100,000 years or so, may be too narrow.
"Statistically, we should be concentrating on rocks down around the 300-to-200 meters (984-to-656 feet)," said Brian Marsden, of the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics. "We'd need to do it, of course, which much more effort than we do today, and with larger telescopes." Those smaller asteroids hit the Earth every millenium or so, with even small chunks impacting very century.
Marsden told SPACE.com that while ESA's SIMONE concept is on the right track in terms of which targets to visit - the five initial asteroids selected range in diameter from 390 meters to 1,100 meters - he doubts that visiting individual rocks would lead to better impact estimates.
"You can find Earth-crossing asteroids from the ground, and it takes time," he added. "It's more an orbital problem which is not going to be done in a mission like this."
But where SIMONE can help is in the countermeasure department, Marsden said. The data from each SIMONE probe should give astronomers a plethora of data of the composition, mass and characteristics of a spectrum of asteroids. With enough of that data in hand, astronomers and world leaders could develop the tools and methods necessary to prevent an impending impact.
""If something is really going to hit us, it isn't going to just go away," Marsden said. "So what are you going to do? Do you try to hit it or break it into pieces? That's where this project becomes useful."
SIMONE rides shotgun
ESA officials said the compact design of each SIMONE probe means more than just a cheap spacecraft that fits in a box.
"The main point of using a microsatellite is not because we want to so something small," said Gálvez. "It also makes it much easier to find launch opportunities."
In theory SIMONE should be small enough to be launched as a secondary passenger on its Ariane 5 rocket, meaning the ESA wouldn't have to pay top dollar for using the launch vehicle. That ability increases the flexibility of the SIMONE concept for use in a variety of other missions as well.
Researchers are already studying the possibility of SIMONE+, a larger spacecraft similar in design to its smaller precursors that could be used for missions to Mars and other planets.
Green said the SIMONE project has yet to progress past the development and study stage, largely due to a lack of funding. With the appropriate funds in hand, he added, SIMONE probes could be launched by 2008 and make their first asteroid rendezvous within a four-year period
| Posted By: Nomad May 29, 2003 - 09:23 am | | Secret Columbia Testimony Will be Available to Congress
WASHINGTON -- Lawmakers on Capitol Hill will have access to secret testimony heard by the Columbia Accident Investigation Board (CAIB), sources tell SPACE.com.
Discussions between congressional staffers and the board are continuing on the mechanics of meeting both the needs of Congress to conduct thorough oversight of federal agencies and the board’s pledge to protect the identities of key witnesses who provided important information.
CAIB chairman Harold Gehman, a retired Navy Adm., said the board granted privacy not so much to ensure truthfulness, but to encourage witnesses to volunteer information they might otherwise hold back.
"It cannot be done any other way in our opinion," he told lawmakers concerned about the practice, promising that the end result will be "a better product."
Gehman told reporters after a hearing before the Senate Commerce, Science and Transportation Committee in Washington that the board has promised anonymity to some 200 individuals who have given testimony to the accident investigation board.
While the board intends to honor its agreements with those individuals within the fullest extent of the law, Gehman said he also believes a solution can be reached that will allow lawmakers to exercise their full oversight responsibilities without making the sworn statements public.
Some lawmakers took exception with the idea of privileged testimony in the first place.
"It’s not going to be credible with the American people unless it is made public. Secrecy may be policy in military investigations, but NASA is a civilian agency," said U.S. Sen. Bill Nelson, D-Fla., who flew aboard Columbia in 1986.
According to congressional sources, accommodations will be made whereby a limited number of congressional staffers will be permitted controlled access to the complete witness statements.
A staffer assigned to one of the Congressional oversight committees with responsibility for NASA said this week that the details are still be worked out.
Past experience such as when members of Congress need access to classified military information, suggests appropriate staffers will be able to examine the statements, for example, in a central location with controlled access but not be allowed to make copies of the documents.
The option of holding privileged testimony was made possible by putting all CAIB members on the federal payroll, a move that also raised eyebrows and prompted some to question the independence of the five civilian board members who are now being paid with a NASA check.
"NASA does not pay our salaries, you pay our salaries," Gehman told lawmakers, many of whom had voted earlier this year to add $50 million to NASA’s 2003 budget to defray the cost of the Columbia accident investigation.
"NASA keeps the books for me but I spend that money, so somehow suggesting that members of this board are influenced by the book, by the way the records are kept, I find to be somewhat naïve," Gehman said.
For the record, Gehman is being paid an annual rate of $142,500 for chairing the board. His check comes from the Office of Personnel and Management.
Seven of the board members were already on the federal payroll when they were assigned to the CAIB.
The remaining five board members -- four professors and one retired business executive -- are now receiving checks issued by NASA. Their annual rate of pay is $134,000.
John Logsdon of George Washington University and Sally Ride of the University of California at San Diego are on unpaid leave from their employers. Douglas Osheroff of Stanford University is not. A spokesman for the Massachusetts Institute of Technology did not return a call asking about Sheila Widnall's employment status.
| Posted By: Nomad May 29, 2003 - 09:24 am | | Columbia Board May Recommend Shuttle Test Flight
By Marcia Dunn
HOUSTON (AP) -- The Columbia accident investigators said Wednesday they may recommend that NASA stage a demonstration space shuttle flight before resuming full-scale missions.
Retired Navy Adm. Harold Gehman Jr., chairman of the Columbia Accident Investigation Board, said the possibility of such a test flight appears unlikely, at least for now. But he said the idea is being considered by the panel and might be among its return-to-flight recommendations ``if we think that's what it takes'' to safely resume missions.
Gehman did not elaborate on what a demonstration flight might entail. But Columbia's first four flights, back in 1981 and 1982, were considered test flights by NASA. Each time, only two pilots were aboard -- instead of the full crew of five to seven -- and they had ejection seats.
NASA spokesman James Hartsfield said the board has not yet asked the space agency to look into the possibility of a demonstration flight. NASA will await the board's recommendations before putting together any return-to-flight plans, he said.
The recommendations almost certainly will include the need to re-evaluate shuttle inspections and closer oversight by NASA, whose role has dwindled dramatically over the past several years, the board noted.
Columbia was on its 28th flight when it shattered over Texas on Feb. 1, killing all seven astronauts. The board suspects a piece of foam that broke off the fuel tank during liftoff put a hole in the leading edge of the left wing, allowing scorching atmospheric gases to penetrate during re-entry.
The investigation board also is considering whether some or all of the shuttle components should be recertified for another 20 years of flight. In the military, recertification of aging airplane parts can be a long, extensive process.
Gehman and others on the 13-member board will start moving to Washington next week and begin writing their final report, expected to be completed by the end of July. He expects a "very, very thick report," extending all the way back to when NASA decided to build space shuttles.
At Wednesday's news conference, Air Force Brig. Gen. Duane Deal said he and others on the board are focusing on the need to improve the quality of NASA's hands-on shuttle inspections, which have decreased because of a shift in this work to contractors.
Until the mid-1990s, NASA itself conducted more than 40,000 inspections at Florida's Kennedy Space Center in preparation for a shuttle flight, compared with 8,500 right before the Columbia disaster, Deal said.
No one interviewed by the board -- "from line technicians all the way through management" -- was satisfied with the quality or number of inspections, Deal said. Some critical inspections that have been turned over to outside contractors should be overseen more closely by NASA once more, he said.
"There are a few things that NASA is not laying their eyes on that are critical ones ... and we believe that they should be laying their eyes upon all those crit-one items," Deal said. He cited an instance in which NASA checked a rope and line used to mate the fuel tanks and booster rockets, but did not look at the alignment itself, and another case where NASA inspected a hydraulic pump but paid no attention to the way it was installed.
Deal said closer NASA oversight would not have necessarily detected the foam defects that are believed to have doomed Columbia. The numerous air pockets and other flaws recently found in the insulating foam on spare fuel tanks were all beneath the surface, he said.
Nevertheless, the entire quality assurance program needs to be looked at again by NASA and perhaps revamped, Deal said.
In other news, the board said it may have identified yet another instance in which insulation foam broke away from the so-called ramped area of a fuel tank during liftoff. This flight, by Challenger in 1985, would bring to seven the number of such cases before Columbia's mid-January launch. Until recently, NASA was aware of only four previous cases.
And the mystery object that was seen floating away from Columbia on Day Two of its flight most likely was half of a seal that had broken off from the damaged leading edge of the left wing, the board said.
| Posted By: Nomad May 29, 2003 - 09:26 am | | Rosetta Comet Mission Finds a Target
The European Space Agency's (ESA) delayed Rosetta mission to a comet is back on track.
During its meeting on May 13-14, ESA's Science Program Committee decided Rosetta should be sent to Comet Churyumov-Gerasimenko.
Rosetta was originally designed as a long haul mission to encounter Comet Wirtanen in 2011.
But a December 11, 2002 failure of a souped-up version of the Ariane 5 launcher -- using hardware common to a standard-version Ariane 5 that would shove Rosetta into space -- caused a major review of the booster.
A special review board was established to advise on the launch of Rosetta, given the Ariane 5 booster problems. That board's findings prompted the rocket's operator, Arianespace, and ESA to postpone Rosetta's departure. The result: Rosetta's launch was left in limbo.
ESA has now come to grips with the Rosetta mission. The decision has been made to send the comet probe spaceward to reconnoiter Comet Churyumov-Gerasimenko. Blastoff aboard an Ariane 4 G-plus rocket is now set for February 2004 from Kourou, French Guiana.
Rendezvous with the new target comet is expected in November 2014.
-- Leonard David
May 28
NASA Contractor Caught Hacking Satellite Signal
Busy minds. Busy hands. A NASA contractor has been indicted for using his talents to build and distribute hardware that illegally accesses DirecTV satellite signals.
NASA's Office of Inspector General stated May 27 that a computer technician with United Space Alliance (USA) -- a contractor at NASA's Johnson Space Center in Houston, Texas -- along with four others were indicted by a Texas Grand Jury for manufacturing and distributing devices to hack DirecTV's satellite signal.
The USA employee operated a privately owned Internet-based business called Digital Smartcard Solutions.
DirecTV officials reported to the NASA Office of Inspector General that they had traced unauthorized access to their networks from a NASA computer network. Federal search warrants were executed at the alleged perpetrator's residences in Houston, Texas; Urbana, Illinois; and Lincoln, Nebraska.
During these searches, agents seized electronic equipment, manufacturing tools, and thousands of hacking devices in various stages of assembly. The manufacture or delivery of devices used to illegally intercept a satellite signal is a violation of federal and state statutes.
If convicted in a District Court in Texas, each defendant faces a maximum penalty of two to ten years of imprisonment.
Mars probes find more frozen water
WASHINGTON, June 26 — The Martian north pole is honeycombed with frozen water, exceeding the ice deposits detected on Mars’ southern end and raising hopes of finding traces of past microscopic life, astronomers say.
THE NORTHERN ICE lies just below the Red Planet’s surface, according to Bill Boynton of the University of Arizona, part of a team of U.S. and Russian scientists who made the discovery.
What they actually detected was hydrogen, which combines with oxygen to form water, but they spotted so much hydrogen that it could not have been anything else, Boynton said in a telephone interview.
“There’s just so much of it (hydrogen), it can’t be present in any other form,” Boynton said. He explained that small amounts of water are normally present in rocks and soil on Earth, but on Mars’ north pole, “we’re seeing amounts that are on the order of 80 to 90 percent ice by volume.”
The ice is uniformly distributed throughout the Martian soil, he said.
“What we think ... is you could go almost anywhere in these high northern latitudes and dig down several inches (centimeters) to a foot (30 centimeters) or so and find ice there for you,” Boynton said.
This is good news for those who believe life might have been present on Mars in the past, since liquid water is a prerequisite for the development of Earth-type life.
If Mars was warm and wet at some point, as many astronomers think, the current wide distribution of ice would indicate a large region where water might have been capable of supporting life.
The U.S.-Russian team, whose findings were published in the journal Science, used data from the Mars Global Surveyor and Mars Odyssey, two NASA vehicles orbiting Mars.
Mars Odyssey first found evidence of subsurface ice around the Martian south pole about a year ago. The scientists found about one-third more ice in the northern polar region than in the south.
from http://www.msnbc.com/news/931744.asp
NASA launches Mars rover
CAPE CANAVERAL, Fla., July 7 — After nearly two weeks of delays, a rocket holding NASA’s second Mars rover was launched into a night sky Monday on a mission to study whether the Red Planet ever had enough water to sustain life.
THE ROVER, Opportunity, lifted off in a cloud of steam aboard a Delta II Heavy rocket at 11:18 p.m. EDT. NASA Administrator Sean O’Keefe flew to the Cape Canaveral Air Force Station to watch the launch.
The launch had been postponed more than a half-dozen times because of bad weather, a failed battery cell and a nagging problem with cork insulation failing to stick to the aluminum rocket.
Technical problems continued to plague the launch Monday night. Launch officials halted the countdown with seven seconds left during the first launch opportunity at 10:35 p.m. EDT because of a problem with a valve on the rocket.
more here: http://www.msnbc.com/news/935709.asp
World’s biggest dish opens wider
DK: read about the "$1 million makeover to open its window on the radio universe seven times wider."
What dish: "Scientists
giving Arecibo Observatory
a makeover
as it turns 40"
Read more here:
http://www.msnbc.com/news/942202.asp
NASA lander to target Martian north pole
15:53 05 August 03
NewScientist.com news service
A mission to explore the frozen north pole of Mars as part of the search for past, or even present, microbial life has been selected by NASA for launch in 2007.
The Phoenix mission will send a lander to a frozen region of the planet to dig out soil samples for detailed chemical analysis. Scientists hope this will reveal whether the poles could provide a viable habitat for life today, or did so in the past.
The mission was selected as NASA's first Scout mission, ahead of other proposals that included a Martian plane and an orbiter that would have studied the planet's volcanic activity.
Vast amounts of frozen water were detected at both Martian poles by NASA's Mars Odyssey spacecraft in May 2002. Up to 50 centimetres below the surface, frozen water may make up 80 per cent of the soil volume.
There is already some evidence that liquid water once washed across the surface of Mars. As water is crucial for life on Earth, this may have supported life on Mars as well. And because some microbial organisms can survive in frozen water on Earth, the frozen expanses of Mars could, perhaps, still harbour primitive life.
More here:
http://www.newscientist.com/news/news.jsp?id=ns99994020
NASA targets spring 2004 for shuttle return
18:35 05 August 03
NewScientist.com news service
NASA's efforts to launch its next space shuttle flight, the first since the Columbia disaster, are focused on March 2004, the agency said on Tuesday.
NASA cautions that the date is a planning target, not a deadline that must be met. The plan (STS-114) calls for Atlantis to deliver the Raffaello multi-purpose logistics module to the International Space Station.
The launch window from 11 March to 6 April meets "all the constraints" imposed on a return to flight, said Bill Readdy, NASA associate administrator for space flight.
It allows a daylight launch, so the separation of the external tank can be photographed to spot any falling debris, as recommended by the Columbia Accident Investigation Board (CAIB). The window also means the shuttle could dock at the space station without excessive heating, a concern at some times of the year.
Furthermore, changes already known to be needed should be completed by that time, including modifying the external tank to eliminate the troublesome bipod foam that felled Columbia, said Readdy. Setting a target date starts the process of preparing for the next launch.
NASA deputy administrator Fred Gregory added: "We are committed to returning to flight, but we are committed to do so safety." If more work is required, the launch will slip to a later date, he said.
more here: http://www.newscientist.com/news/news.jsp?id=ns99994023
Starlight Express (from wired.com, home of wired mag, published in mag)
Nanotech's promise is out of this world. Just ask Brad Edwards, who's planning to build a carbon-nanotube elevator that goes 62,000 miles straight up.
By Kevin Kelleher
DK: Highlights:
The founder of Seattle-based Highlift Systems, Edwards proposes a carbon-nanotube space elevator: a ribbon 62,000 miles long, 3 feet wide, and thinner than the paper your thumb is pressed against right now. The elevator would stretch high into the heavens, allowing easy transport from Earth, launching spacecraft, new industries, even tourists - at a fraction of today's costs. And he says he can be well under way in a decade, ushering in a new era of space exploitation.
On a recent day in his small office there, Edwards holds up a black strip 2 feet long. It's a prototype of the ribbon, hundreds of hairlike fibers strung together to distribute tension. The strip represents what could be Highlift's first commercial product, a nanotube composite four times stronger than steel. When it hits the market, it could be used to, for example, make superstrong tennis rackets, create cars and planes that are at once lighter and sturdier, and add decades of durability to infrastructure projects like bridges or freeways. Within two to three years, Highlift should have a material strong enough for the space elevator ribbon.
The elevator itself will be built upon something resembling an offshore oil platform (way offshore: Highlift is looking at a site in the eastern Pacific, 1,000 miles from the Galápagos Islands). Construction would start with expendable rockets (such as the Delta 4 or Atlas 5) shooting into low Earth orbit. There, the rockets will link up, creating an 80-ton spacecraft that will ascend to 22,000 miles and lock into geosynchronous orbit.
From there, the craft will unreel the ribbon 40,000 more miles into space, and lower a weighted ribbon to the ocean platform (centripetal force will do most of the work getting it up; gravity will help get it down). Edwards estimates that the ribbon will land within 100 miles of the platform; a GPS locator and beacon on the ribbon's end will help a ship retrieve it and attach it to the platform.
With a counterweight attached at the far end, the strand will stay taut through sustained centripetal force. Now comes the heavy lifting: 7-ton climbers, each the size of a semitrailer, will ascend the ribbon at 120 miles an hour, carrying payloads weighing as much as 13 tons. The climbers will be powered by earthbound free-electron lasers, which is the same tech behind Stanford's linear accelerator. The lasers are aimed at photocells on the climbers' undersides, the photocells power the climbers' motors, and the elevator goes up. Edwards reckons it will feel like taking an elevator in a tall building. In a few hours, you'll reach outer space. In two weeks, you'll reach the ribbon's end - one quarter of the way to the moon.
The economies of scale behind the space elevator could make a trip into space as mundane as a trip to Maui. Launching a pound of cargo by rocket or space shuttle runs about $40,000. Edwards figures the space elevator can do it for $200, a figure that could drop to $10. Go weigh yourself and multiply.
He's received $570,000 from NASA's Institute of Advanced Concepts program, which funds experimental projects, and hopes for more from Darpa and the Air Force. Highlift expects private investors to put up much of the $40 million for its composite. Later, the company will pass the hat again, for $7 billion, to build the elevator itself.
http://www.wired.com/wired/archive/11.04/nanotech.html?pg=2&topic=&topic_set=
| Posted By: poppie Oct 02, 2003 - 09:52 pm | | SMART-1, Europe's first science spacecraft designed to orbit the Moon, has completed the first part of its journey by achieving its initial Earth orbit after a flawless launch during the night of 27/28 September.
The European Space Agency's SMART-1 was one of three payloads on Ariane Flight 162. The generic Ariane-5 lifted off from the Guiana Space Centre, Europe's spaceport at Kourou, French Guiana, at 2014 hrs local time (2314 hrs GMT) on 27 September (01:14 Central European Summer time on 28 September).
42 minutes after launch, all three satellites had been successfully released into a geostationary transfer orbit (742 x 36 016 km, inclined at 7 degrees to the Equator). While the other two satellites are due to manoeuvre towards geostationary orbit, the 367 kg SMART-1 will begin a much longer journey to a target ten times more distant than the geostationary orbit: the Moon.
Europe can be proud", said ESA Director General Jean-Jacques Dordain, after witnessing the launch from ESA's ESOC space operations centre in Darmstadt, Germany, we have set course for the Moon again. And this is only the beginning: we are preparing to reach much further".
The spacecraft has deployed its solar arrays and is currently undergoing initial checkout of its systems under control from ESA/ESOC. This checkout will continue until 4 October and will include with the initial firing of SMART-1's innovative ion engine.
Science and technology go hand in hand in this exciting mission to the Moon. The Earth and Moon have over 4 thousand million years of shared history, so knowing the Moon better will help scientists in Europe and all over the world to better understand our planet and will give them valuable new hints on how to better safeguard it" said ESA Director of Science David Southwood, following the launch from Kourou.
As the first mission in the new series of Small Missions for Advanced Research in Technology, SMART-1 is mainly designed to demonstrate innovative and key technologies for future deep space science missions.
The first technology to be demonstrated on SMART-1 will be Solar Electric Primary Propulsion (SEPP), a highly efficient and lightweight propulsion system that is ideal for long-duration deep space missions in and beyond our solar system. SMART-1's propulsion system consists in a single ion engine fuelled by 82 kg of xenon gas and pure solar energy. This plasma thruster relies on the Hall effect" to accelerate xenon ions to speed up to 16,000 km/hour. It is able to deliver 70 mN of thrust with a specific impulse (the ratio between thrust and propellant consumption) 5 to 10 times better than traditional chemical thrusters and for much longer durations (months or even years, compared to the few minutes' operating times typical of traditional chemical engines).
The ion engine is scheduled to go into action on 30 September. At first, it will fire almost continuously -stopping only when the spacecraft is in the Earth's shadow - to accelerate the probe (at about 0.2 mm/s2) and raise the altitude of its perigee (the lowest point of its orbit) from 750 to 20 000 km. This manoeuvre will take about 80 days to complete and will place the spacecraft safely above the radiation belts that surround the Earth.
Commissioning will be completed within 2 weeks, after which ESA's control centre at ESOC will be in contact with the spacecraft for two 8-hour periods every week.
Once at a safe distance from Earth, SMART-1 will fire its thruster for periods of several days to progressively raise its apogee (the maximum altitude of its orbit) to the orbit of the Moon. At 200 000 km from Earth, it will begin receiving significant tugs from the Moon as it passes by. It will then perform three gravity-assist maneuvers while flying by the Moon in late December 2004, late January and February 2005. Eventually, SMART-1 will be captured" and enter a near-polar elliptical lunar orbit in March 2005. SMART-1 will then use its thruster to reduce the altitude and eccentricity of this orbit.
During this 18-month transfer phase, the solar-electric primary propulsion's performance, and its interactions with the spacecraft and its environment, will be closely monitored by the Spacecraft Potential, Electron & Dust Experiment (SPEDE) and the Electric Propulsion Diagnostic Package (EPDP) to detect possible side-effects or interactions with natural electric and magnetic phenomena in nearby space.
A promising technology, Solar Electric Primary Propulsion could be applied to numerous interplanetary missions in the Solar System, reducing the size and cost of propulsion systems while increasing manoeuvring flexibility and the mass available for scientific instrumentation.
In addition to Solar Electric Primary Propulsion, SMART-1 will demonstrate a wide range of new technologies like a Li-Ion modular battery package; new-generation high-data-rate deep space communications in X and Ka bands with the X/Ka-band Telemetry and Telecommand Experiment (KaTE); a computer technique enabling spacecraft to determine their position autonomously in space, which is the first step towards fully autonomous spacecraft navigation.
In April 2005 SMART-1 will begin the second phase of its mission, due to last at least six months and dedicated to the study of the Moon from a near polar orbit. For more than 40 years, the Moon has been visited by automated space probes and by nine manned expeditions, six of which landed on its surface. Nevertheless, much remains to be learnt about our closest neighbour, and SMART-1's payload will conduct observations never performed before in such detail.
The Advanced/Moon Micro-Imaging Experiment (AMIE) miniaturised CCD camera will provide high-resolution and high-sensitivity imagery of the surface, even in poorly lit polar areas. The highly compact SIR infrared spectrometer will map lunar materials and look for water and carbon dioxide ice in permanently shadowed craters. The Demonstration Compact Imaging X-ray Spectrometer (D-CIXS) will provide the first global chemical map of the Moon and the X-ray Solar Monitor (XSM) will perform spectrometric observations of the Sun and provide calibration data to D-CIXS to compensate for solar variability.
The SPEDE experiment used to monitor Solar Electric Primary Propulsion interactions with the environment will also study how the solar wind affects the Moon.
The overall data collected by SMART-1 will provide new inputs for studies of the evolution of the Moon, its chemical composition and its geophysical processes, and also for comparative planetology in general.
http://www.astrobio.net/news/article609.html
| Posted By: Nomad Oct 22, 2003 - 09:38 am | | Light Sails to Orbit
NASA watches from the sidelines as Cosmos 1, the first solar sail, goes up
By Philip Yam
Shiny and crinkly, the material looks more like something meant to wrap frozen foods than to provide a new way to travel through space. The aluminized Mylar reflects sunlight, thereby deriving a little kick from the recoiling photons. In principle, big sheets could act as solar sails that over time would reach speeds exceeding 100 kilometers a second—far faster than chemical rockets.
The first solar sail, called Cosmos 1, will go for its test flight in early 2004. The demonstration of a revolutionary way to travel to the planets and maybe even to the stars would seem to be a natural activity for NASA, which spends several million dollars every year researching advanced propulsion systems. Yet in this case, the space agency has chosen to be a bystander.
The successful flight of Cosmos 1 would mark the culmination of three years of effort by the Planetary Society, a space-interest group, and the entertainment media firm Cosmos Studios [see "Sailing on Sunlight," News Scan, Scientific American, July 2001]. Both organizations, which can trace their roots to the late Carl Sagan, used their connections with Russian space officials and engineers. They enlisted the Babakin Space Center in Moscow as the prime contractor for Cosmos 1, which cost $4 million—cheap in the space-travel world. The craft consists of eight triangular Mylar panels 14 meters long stretched across inflatable spars. The goal is to have Cosmos 1 ride atop a modified ballistic missile launched from a Russian submarine. Once in orbit, the spacecraft would inflate the spars to unfurl the sails. The panels would spread out like flower petals and cover about 600 square meters. Then sunlight should push the sails, lifting Cosmos 1 into a higher orbit from its initial 800-kilometer altitude.
Russian involvement may be one reason NASA has shied away, suggests Louis D. Friedman, executive director of the Planetary Society. Informal discussions had NASA supplying the sail material, which is tougher and, at 2.5 microns thick, half the thickness (and therefore half the weight) of the Russian film being used. "We would have gotten it for free and tested it for them," Friedman says. But NASA management never gave the go-ahead. Bureaucracy might have been a problem, he surmises, with the "upper echelons fearing private companies working with the Russians on a submarine launch." In any case, strict rules govern how closely NASA can work with other countries, remarks Hoppy Price, who was the lead solar-sail engineer for NASA at the Jet Propulsion Laboratory in Pasadena, Calif. "Possibly NASA is worried about the transfer of technology," he notes. Moreover, solar sails may provide some military advantage that the U.S. would rather not share. One proposed application, for instance, has solar sails hovering over the poles to provide valuable up-links to anyone at the earth’s communications-starved extremities.
Image: COURTESY OF THE PLANETARY SOCIETY AND COSMOS STUDIOS
READY TO GO:Louis D. Friedman, Cosmos 1 project director, gives the craft a once-over. He had hoped for a test flight in October; scheduling conflicts with the Russian navy has pushed the date to early 2004.
Risk, though, is probably the main reason for NASA’s noninvolvement. Battered by a bruising report about the Columbia disaster as well as by the loss of two Mars-bound spacecraft in 1999, the agency "can’t spend taxpayer money with the level of risk" that the Cosmos 1 team is taking, notes Neil Murphy, who currently coordinates the solar-sail work at JPL. Plenty of pitfalls abound. "Concern lies with what happens to an ultrathin material over tens of meters," Friedman says, noting that engineers have no good way on the earth to test the behavior of the material in zero gravity. "You can imagine all sorts of problems—take Saran Wrap and wave it around," he offers. Ripping, fluttering and sagging would all undermine the sail’s ability to reflect photons.
NASA would also want a solar-sail launch to have science-based goals to refine models and to plan the next mission, Murphy explains. Cosmos 1 is mostly a demonstration, and the components are not suitable for an extended voyage. The inflatable spars, for example, will not remain rigid for long because of the inevitable micrometeoroid impacts.
NASA is working on a more advanced solar-sail craft, probably to be configured as four square panels, but it won’t be ready for at least another few years. That leaves the privately organized Cosmos 1 as the lone player—and NASA engineers in the cheering section.
http://www.sciam.com/article.cfm?chanID=sa004&articleID=00042A0E-6B16-1F8D-AB1683414B7F0000
| Posted By: iamume Oct 22, 2003 - 11:55 am | | cool
| Posted By: Nomad Nov 10, 2003 - 09:33 am | | European Planet-Finding Mission Cancelled
By Peter deSelding
Space News Staff Writer
posted: 12:30 pm ET
07 November 2003
European space-science managers buckled under financial pressures and cancelled a planet-hunting mission slated for 2007 and a Mercury lander that had been scheduled for launch around 2011.
The two Mercury orbiters, including a Japanese satellite, planned for the BepiColumbo Mercury mission were not affected by the elimination of the lander.
The decision by the Space Science Committee (SPC) was made Nov. 6 following a recommendation of an advisory group. The SPC sets Europe’s space-science priorities within the budget guidelines of the European Space Agency (ESA).
The planet-hunting spacecraft mission, called Eddington, had been budgeted at about 200 million euros ($230 million), and the Mercury lander at about 250 million euros. The decision to cancel them will give financial breathing room to a European space-science program that had none.
“We knew at the start that our program would leave us very little room for error,” ESA Science Director David Southwood said in a Nov. 7 interview. “It worked only if almost nothing went wrong. Well, a couple of things did go wrong.”
What went wrong were launch delays and instrument cost overruns. ESA’s Herschel and Planck science satellites, to be launched together in 2007, have run into trouble with development of their observing instruments, forcing ESA to spend 20 million euros more than planned to assure completion.
An additional 10 million euros more were needed for the agency’s Smart-1 technology satellite, now on its way to the moon, because of a six-month launch delay following a December 2002 Ariane 5 launch failure. That same launch failure pushed back by a year the launch of ESA’s billion-dollar Rosetta comet-chaser satellite, now set for launch in February. The Rosetta delay -- satellite storage, keeping launch teams together and other charges — added 40 million euros to ESA’s science program bill.
Pleading exceptional circumstances, Southwood secured a 100-million-euro loan from ESA’s general treasury in May, but these funds must be paid back by late 2006.
Adding to the problems was the fact that European companies on contract to ESA for science hardware demanded early payments for their work in return for accepting contract terms favorable to ESA. These early contract payments added about 30 million euros in unanticipated charges to ESA’s 2003 bills.
“Killing a mission, especially one like Eddington, really hurts,” Southwood said. “The reaction from the science community, in Europe and elsewhere, has been strong. Eddington would have been center stage in the effort to find Earth-like planets. If there had been any way to keep it, I would have. But the only way would have been to drop LISA, and LISA is Nobel Prize territory.”
LISA, or Laser Interferometer Space Antenna, will attempt to detect gravity waves from black holes. A Lisa Pathfinder satellite is set for launch in 2007 and the main LISA spacecraft planned for 2012. LISA will now be the only science mission that will be started in the next two years.
“The choice before the SPC was relatively simple,” said Bo Andersen, a current SPC member and its past president. “Do we start LISA Pathfinder, or Eddington? We knew we had a program that had no margins, but the decision was painful. We all knew that Eddington would be world-class and put Europe ahead of the rest of the world in this field.”
Andersen said some SPC members are considering whether to propose that future ESA science budgets be spared the consequences of cost problems caused outside the science program -- in this case the Ariane 5 rocket.
“The science program has had three big launches on Ariane 5 Cluster 1, Rosetta and Herschel-Planck, and two out of three so far have been painful for us,” Andersen said. The 1995 launch of four Cluster science satellites ended in failure when the rocket veered out off course and was destroyed. A new set of Cluster satellites was subsequently built and launched on Soyuz rockets in 2000.
ESA’s science budget has been frozen since the mid-1990s at a level of about 370 million euros per year. To this figure is added most of the costs of science satellites’ observing instruments, financed by national space agencies.
Getting the national agencies to meet their payload-development commitments has been one of Southwood’s highest priorities. He said he has given the national agencies until Dec. 15 to commit to providing all the components of an infrared observation instrument to be provided to NASA for the James Webb Space Telescope to be launched around 2010. ESA is also tentatively scheduled to provide an Ariane 5 launch for the mission.
http://www.space.com/scienceastronomy/eddington_esa_031107.html
| Posted By: Nomad Nov 10, 2003 - 09:59 am | | Mystery: Is Voyager at Solar System's Edge?
By Robert Roy Britt
Senior Science Writer
posted: 01:21 pm ET
05 November 2003
Voyager 1 has phoned in from the edge of the solar system to let us know what it's like out there. Now scientists are arguing over whether the 26-year-old spacecraft has really reached a telltale and important boundary.
Controversy is brewing over whether Voyager 1 has crossed the termination shock, a poorly understood envelope some 8.4 billion miles (13.5 billion kilometers) away, where supersonic particles from the Sun -- riding out on the so-called solar wind -- should slam into interstellar plasma and drop to subsonic speeds.
New Voyager data show something is up, but it's not clear what.
Astronomers expect the boundary to be somewhere between 85 and 120 astronomical units from the Sun (1 AU is the distance from Earth to the Sun). Launched in 1977, Voyager 1 is 90 AU from the Sun as of today -- farther from Earth than anything else that's ever left this world and well beyond the solar system's nine planets.
Two interpretations
Voyager recorded a large increase of a certain type of energetic particles, hinting that the craft has detected the expected drop in solar wind speed and has encountered interstellar plasma, according to research led by Stamatios Krimigis of the Applied Physics Lab at John Hopkins University.
Krimigis and his colleagues argue the spacecraft exited the supersonic solar wind, possibly beyond the termination shock, on about Aug. 1, 2002 at a distance of 85 AU from the Sun and re-entered it about 200 days later at 87 AU.
Another team, however, has a different take on the data. A study led by Frank McDonald at the University of Maryland concludes Voyager has yet to reach the termination shock.
"Either way, Voyager 1 has entered a region of our solar system that has never yet been explored," says University of Michigan professor Len Fisk, who was not involved in either study.
The two interpretations were discussed at a NASA press conference today and will be published in the Nov. 6 issue of the journal Nature.
Outbound
Voyager 1 will eventually pass the termination shock and, barring catastrophe, other expected boundaries. That will put the craft in interstellar space. Scientists are eager to learn as much as possible during this first trip through the edge of the solar system before the machine runs out of fuel in about the year 2020, rendering it unable to communicate.
Voyager 2, launched in the same year, is about 70 AU away. Both robotic explorers are headed toward two other boundaries beyond the termination shock. The heliopause marks the region where the solar wind no longer exists and interstellar plasma rules. Then there is the bow shock, created by the entire heliosphere plowing through space. The bow shock is akin to the ripple of water raised by a boat's bow.
Previously, Voyager data was paired with observations from the Hubble Space Telescope to find evidence that the outer shell, the bow, shock, in fact exists as theory predicts.
Communications will be lost with both Voyagers before either can reach the bow shock.
In figuring out Voyager 1's environment, researchers are hampered by a non-working onboard plasma detector. It would have directly measured the solar wind speed definitively.
Krimigis' team instead measured one sort of particle, deciding that their quantity and type show the solar wind must have slowed down. McDonald's team analyzed a different sort of energetic particles and determined they were accelerated somewhere else, out beyond Voyager's location, and suggest Voyager has yet to reach the termination shock.
Fisk, who analyzed the two papers for Nature, says the termination shock is probably not a fixed boundary anyway. Its location will vary depending on solar activity and may in fact be moving outward now and for the next few years.
Advantage Krimigis
"I tend to agree with Krimigis [and colleagues] that their data can most readily be explained if the termination shock has been crossed," Fisk writes. He says it's possible the shock front then moved outward, putting Voyager back inside it. Fisk said McDonald's analysis suggests either Krimigis is wrong or the termination shock could have a more complex shape than scientists expected.
Only more data from Voyager 1 -- if it encounters the boundary either again or for the first time -- will settle the issue, Fisk said.
The twin Voyager missions explored all the gas giant planets before trekking out beyond Pluto. Voyager 1 is the most distant manmade object. Each spacecraft carries a gold record that serves as a "greeting to the universe," with sounds and images selected to portray the diversity of life and culture on Earth.
http://www.space.com/scienceastronomy/voyager_mystery_031105.html
Very neat information - thanks Nomad!
Now all we have to do is wait for it encounter an alien life form and come back looking for a bald woman to bond with.
| Posted By: Nomad Nov 10, 2003 - 10:38 am | | LoL ...Has to be a Delvian ... Love that movie!
| Posted By: Aldan Nov 13, 2003 - 10:06 am | | Vger!!!
| Posted By: Nomad Nov 18, 2003 - 08:43 am | | Now in their sights: Hubble’s demise
NASA and scientists debate method of telescope’s future fall
By Kathy Sawyer
THE WASHINGTON POST
WASHINGTON, Nov. 17 — The Hubble Space Telescope must die. The vexing question is how.
OVER THE PAST DECADE, thousands of astronomers in the United States and abroad have used the observatory orbiting 350 miles above Earth to take measure of the universe and probe its deepest mysteries. The Hubble’s dazzling images are now woven through the popular imagination. In a current children’s movie, a dog is named after it.
The telescope is still in demand for research, and its obituary is presumably at least several years in the future. Nevertheless, in recent weeks, many of those closest to the historic project have been locked in emotional battle over how — and when — its decline and fall should be managed.
To avert a public fight at a meeting scheduled today at NASA’s Ames Research Center in California, the leading combatants — NASA officials and outside scientific leaders — reached a temporary compromise Friday morning in a hastily called meeting at NASA headquarters. But thorny issues are still on the table.
Some of the telescope’s systems are showing the effects of 13 years of wear and tear in space. A far more advanced successor is being readied, and NASA officials have long maintained that the Hubble must be retired in a few years to free up money to pay for the newcomer.
A number of Hubble scientists have hotly disagreed with agency officials recently about how much more scientific productivity should be squeezed out of the Hubble, and at what cost.
The effort to balance what was already a difficult equation has been hugely complicated by the Feb. 1 loss of the space shuttle Columbia. The Hubble depends heavily on periodic visits from astronauts to keep it healthy and, with the installation of new instruments, at the forefront of science. The timing and number of such missions in the future have been thrown into doubt by the uncertainties and safety constraints that followed the disaster.
At the Friday meeting, the parties agreed to postpone a decision on one of the most contentious issues: whether NASA would consider prolonging the telescope’s useful life until 2020, as recommended recently by a prestigious independent panel of top scientists led by John Bahcall of the Institute for Advanced Study at Princeton.
That would require an extra refurbishing visit by astronauts at an estimated cost of at least $600 million and possibly much more — money that is not currently contemplated in NASA’s budget planning.
STARK CHOICE
NASA upset many space scientists by presenting them with a stark choice: Either sacrifice the extra servicing mission for the Hubble or give up many years worth of smaller, fast-response space science missions.
The two sides agreed Friday to punt that question into the future and avoid what one official called “consternation among other [science] communities” whose programs might have been eliminated in favor of the Hubble. For the near term, the conflicting camps agreed to focus on a much more pressing matter: seeing to it that the one servicing visit already on the shuttle schedule reaches the Hubble in time to keep it going until 2010. That mission, which before the Columbia accident had been set for November 2004, has been delayed until at least mid-2006, and possibly as late as 2008, officials said.
NASA may even decide to complete the initial construction phase of the international space station before sending another shuttle to visit the Hubble, they said. On that timetable, one concerned scientist said, some fear that the batteries could fail, causing the telescope to lose power and start to tumble.
The Friday meeting was called by Edward Weiler, now NASA’s head of space science. Formerly the chief Hubble scientist, Weiler devoted about 20 years of his career to the telescope and saw it through the dark days after its 1990 launch, when astronomers discovered to their horror that a flaw had been built into the telescope mirror. Astronauts later installed what amounted to corrective lenses.
He has not enjoyed being pitted against the Hubble’s defenders, Weiler said.
“We started the meeting by saying, ‘Let’s see how we can avoid a huge conflict that we all saw coming,’” he said in an interview. The parties immediately realized that “we have a lot of common goals here, and we’ve just got to concentrate on what’s important right now.”
‘VERY HIGH PRIORITY’
One of those points of agreement is that the next shuttle servicing mission is “very high priority for science and very high priority for NASA,” said Steven Beckwith, director of the Space Telescope Science Institute in Baltimore, which manages Hubble research in cooperation with the spacecraft controllers at Goddard Space Flight Center in Greenbelt.
“If we can work with NASA to explore opportunities to keep Hubble science alive, I’m very happy,” Beckwith said in an interview after the meeting. “There are no guarantees. I just don’t want to shut the door prematurely.”
He and other Hubble defenders have argued that the telescope, which has cost at least $4 billion, is too valuable to be treated as a mere budget line item.
In an interview a day earlier, Beckwith said he was surprised “at the antipathy displayed toward Hubble” by some NASA officials and “dismayed at the concentration on costs to the exclusion of the potential benefits.”
After the meeting, however, he said he recognizes that “NASA is under very tough budget constraints, especially this year, and they cannot satisfy all the things they would like to do.”
Former astronaut Bruce McCandless, a member of the shuttle crew that deployed the Hubble in 1990, said he favored the “old bird in hand” philosophy: Get the successor telescope launched and working for two years before pulling the plug on the Hubble. “You would hate to de-orbit Hubble and find you had a problem” with the successor, he said in an interview.
HUBBLE’S SUCCESSOR
The James Webb Space Telescope, scheduled for launch in 2011, is designed to observe the universe in infrared wavelengths required to study the most distant galaxies as they accelerate outward. It will not produce the spectacular visible wavelength images for which the Hubble is celebrated.
And, as McCandless and others pointed out, it could suffer the same kind of development delays and post-launch problems that afflicted the Hubble in its early phases.
Critics have also expressed dismay at NASA’s plans to spend scarce research money on what one called a “ludicrous” device designed to plunge the Hubble to a final resting place in the sea.
Before the Columbia accident, NASA intended eventually to have a crew of astronauts maneuver the 43-foot-long telescope into a cargo bay and bring it home for installation in the National Air and Space Museum as an inspiration for future generations. A general unwillingness to subject astronauts to such risks for a museum exhibit, among other things, eliminated that option, Weiler said.
Instead, NASA’s plan now calls for building an unmanned craft, which would be launched on a throwaway rocket and attach itself to the Hubble to steer the telescope safely into the Pacific Ocean — eliminating any possibility that the 12.5-ton telescope could fall on, say, Mexico City or Miami.
Opponents argue that such a device has never been proved and does not exist and that its cost — estimated at $300 million or more — would come out of NASA’s space research budget though it would accomplish no research. “We’ve labeled it EGO — for Eunuch Great Observatory,” on the grounds that the device would cost as much as a whole new space telescope yet “will do nothing,” a Hubble astronomer said.
NASA officials are adamant that they cannot allow the Hubble to reenter the atmosphere out of control.
One alternative would be to have astronauts affix a simpler, less costly propulsion device to the Hubble during the next servicing trip. But, because the Columbia Accident Investigation Board declared the shuttle an experimental, not operational, vehicle, Weiler said, his office can no longer count on a shuttle visit and will have to have a backup plan.
The only feasible backup is the automated propulsion device.
“If I have to do it anyway, why don’t I cut my losses and make it the only money I have to spend?” Weiler asked rhetorically.
Michael R. Moore, a propulsion expert and top Hubble program executive at headquarters, said in an interview that NASA and other agencies had long been interested in an automated docking system of this sort for a range of uses.
He said there are tricky aspects to having a small device capture a large, delicate object such as the Hubble — all without humans aboard to navigate the final yards — but that the technology is within reach.
Even if nobody does anything to shore up the Hubble, Weiler said, the earliest it would begin to fall from orbit would be 2013.
© 2003 The Washington Post Company
http://www.msnbc.com/news/994737.asp
| Posted By: iamume Nov 18, 2003 - 12:05 pm | | Interesting.Funding is the central issue here.It would be a shame to toss the Hubble into the sea prematurely. Hopefully budget issues will change before we go ahead with the EGO progect.There must be a better way to resolve the issue.
| Posted By: Nomad Nov 21, 2003 - 08:28 am | | SpaceShipOne Soars on Fifth Test Flight
By Leonard David
Senior Space Writer
posted: 07:20 am ET
20 November 2003
A fifth glide flight of the privately built SpaceShipOne took place on November 14 at a Mojave, California test site. For the first time, pilot Pete Siebold put the space plane through its paces. Previous drop tests of the vehicle had Mike Melvill at the controls.
SpaceShipOne has been designed and built by Scaled Composites of Mojave, California. Several changes have been made to the craft, based on stability and handling glitches that were uncovered in an earlier drop test. Along with checkout of a new pilot, new extended horizontal tails on SpaceShipOne were also evaluated.
SpaceShipOne was released from the White Knight carrier plane at 47,300 feet.
According to Scaled Composites, SpaceShipOne's control characteristics were found to be good. The drop test flight also involved the vehicle's tail section that moved in and out of a "feathered" position - shifted to a 65-degree angle to the main body. Handling qualities of the rocket plane remained excellent with good nose pointing ability during feathering of the tail section, a test report explains.
Siebold steered SpaceShipOne to a touchdown at a targeted runway aim-point.
Major milestone to come
Aircraft designer and builder, Burt Rutan, head of Scaled Composites, along with his team, are leading the effort to construct and fly the passenger-carrying SpaceShipOne suborbital craft.
Tests are carried out over the desert in Mojave, California. The previous high-altitude drops of SpaceShipOne: August 7, August 27, September 23, October 17, and now the November 14 test. All flights were done in 2003.
The progression of ground and airborne tests is leading to a major milestone: an in-the-air ignition of the craft's propulsion system, a hybrid rocket motor.
Ultimately, SpaceShipOne is to nose its way to the edge of space in a competitive bid to snag the $10 million X Prize. Rocket teams around the globe are eyeing the X Prize purse and are building varying types of suborbital, passenger-carrying vehicles.
Astronomers detect Milky Way’s border
Cosmic arm of gas wraps around our home galaxy
Reuters
Updated: 1:12 p.m. ET Dec. 16, 2003
CANBERRA, Australia - Astronomers have discovered an extra cosmic arm in the Milky Way that they believe wraps around the outskirts of the vast galaxy like a thick gas border.
Astronomers at the Commonwealth Scientific and Industrial Research Organization, or CSIRO, hope the find will help paint a better picture of the Milky Way galaxy, which is home to Earth.
CSIRO scientist Naomi McClure-Griffiths said the gas border, which is 6,500 light-years thick, showed that the Milky Way had a structure similar to those of most other galaxies, which have gassy spiral arms extending beyond the more central stellar spiral arms.
Astronomers believe the Milky Way has about four arms made up of hydrogen gas, dust and stars spiraling out from its center. McClure-Griffiths said the newly discovered gas border is about 60,000 light-years from the centre of the Milky Way.
A light year is the distance that light travels in a year, which is about 6 trillion miles (10 trillion kilometers).
"We have known there was gas out there, but we haven't known that there was a structure out there. We thought there was just a smooth drop-off, that the galaxy just sort of slid away," McClure-Griffiths told Reuters. "It is at the furthest reaches of the galaxy and is the last thing you see before the galaxy disappears."
McClure-Griffiths and a small team of scientists were investigating the hydrogen gas in the disk of the Milky Way when they stumbled across the extra arm, which they believe could connect up with one of the galaxy's central stellar arms.
The finding has been submitted for publication to the Astrophysical Journal of the American Astronomical Society, she added.
http://msnbc.msn.com/Default.aspx?id=3728659&p1=0
| Posted By: Sindatur Dec 17, 2003 - 06:17 am | | I read this on CNN also. But what does it mean exactly? What benefit is it to know of this new arm?
| Posted By: Nomad Mar 06, 2004 - 06:03 pm | | Evidence of water has apparently been found:
www.space.com
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