Saturday, September 10, 2011

NASA'S woes becoming astronomical

Winnipeg Free Press: NASA'S woes becoming astronomical
WASHINGTON -- Like a veteran NFL team, NASA's aging astronauts are piling up injuries, raising concern that the National Aeronautics and Space Administration and its 61-member corps won't have enough healthy astronauts available for rigorous six-month shifts aboard the International Space Station, according to a new report.

Most worrisome is a recently diagnosed and not fully understood eye problem found among some astronauts returning from space that can cause headaches and blurry vision.

"This condition has led to several members of the Astronaut Corps being medically disqualified from flying again until the condition improves," noted researchers for the National Academies in a report made public this week.

The affliction, known as papilledema, involves swelling of the optic disk and can cause blurred vision, blind spots or, in severe cases, loss of vision. It was found in nearly half of 15 astronauts examined in one study by NASA.

This included "some lingering substantial effects on vision," and astronauts were "not always able to requalify for subsequent flights," according to the 102-page report, which provided no additional details.

NASA did not immediately respond to questions about these figures, but papilledema is believed to be a symptom of increased pressure on the brain caused by body fluids shifting in space -- although it's not yet known why it affects only some astronauts.

"It's a significant health concern, and it is one of the major issues NASA will have to contend with," said Dr. Jonathan Clark, a former NASA flight surgeon and an adviser with the National Space Biomedical Research Institute. Clark's astronaut wife, Laurel, died in 2003 when space shuttle Columbia broke up over Texas as it was returning to Earth.

The study by the National Academies, the nation's top science advisers, was requested last year by the White House, which is trying to chart a new, post-shuttle path for NASA. A committee of 13 experts, five of them former astronauts, conducted the study.

Also worrisome for NASA's astronaut corps -- whose average age is nearly 48 -- are more-routine injuries caused by working in a spacesuit.

According to the National Academies report, the bulky suits have forced five crew members in the last 18 months to undergo shoulder surgery and led to 26 injuries to the elbow or shoulder that have required rehabilitation.

Former astronaut Leroy Chiao, who spent six months aboard the station, said he never felt the effects of papilledema but said astronauts long have complained about shoulder injuries, a consequence, he said, of a design change to the upper torso of the spacesuit in the 1990s that reduced the risk of leaks but reduced mobility.

"People were injuring themselves in suits," said Chiao, who noted astronauts often pushed themselves too far. "Working in a spacesuit is physically demanding. There is no doubt about it."

Health was one of several reasons cited by the National Academies as to why NASA should consider increasing the size of its astronaut corps -- despite the retirement of the space shuttle this summer and the bleak prospect of NASA launching a new government-owned rocket before 2017, if then.

National Academies researchers, while not specifying a number, said NASA should go above its plans to keep the corps at 55 to 60 members through 2016 (down from a high of 149 in 2000). Nine astronauts are currently in training.

While the number of NASA astronauts required to staff the station is low -- four to six annually -- the report said many times more were needed to help develop new spacecraft, work ground operations for other missions or be backup in case someone assigned to a station assignment couldn't do it.

"The thing we worry about is if we are not going to be able to fill one of our seats or one of our positions on the space station," said Joe Rothenberg, one of the report's co-chairmen and a former NASA associate administrator.

"It would be a national embarrassment."

Bone loss during spaceflight is another factor. Recovery can take as long as three years from a six-month shift aboard the station, affecting how quickly astronauts can get back into rotation.

Still, an uncertain future for NASA and the station raises questions whether NASA needs a corps of 60 or more astronauts.

Because of recent mechanical trouble with the Russian Soyuz spacecraft -- the only way to transport crew to the station -- NASA and its partners may have to abandon the station this fall if Moscow can't fix the problem.

Then there's another, more Earth-bound concern: money.

While the astronaut office costs only tens of millions of dollars annually -- NASA won't say exactly how much -- the years ahead look increasingly tough as Congress looks to cut spending and the White House asks agencies to submit budgets 10 per cent below current levels, a nearly $2-billion cut to NASA's current $18.5-billion funding level.

In response to written questions, NASA spokesman Mike Curie wrote that the "report offers helpful advice about the appropriate size of our astronaut corps as we enter this exciting new era of space exploration and crew transport operations."

Friday, September 9, 2011

Space Junk FAQ: Falling Space Debris Explained

From Space.com: Space Junk FAQ: Falling Space Debris Explained
A massive, dead satellite that is falling back to Earth on an uncontrolled path is expected to hit the ground sometime in late September, and while most of the debris will break up as it hits the atmosphere, some pieces are expected to reach the ground intact.

NASA's defunct Upper Atmosphere Research Satellites (UARS) is a roughly 13,000-pound (6,000 kilogram) spacecraft that was launched into orbit in 1991 aboard the space shuttle Discovery. The satellite was decommissioned in 2005, and has been drifting in orbit for six years now. [Photos of Space Debris]

Here is a NASA-provided list of frequently asked questions about space debris and falling space junk:

What is orbital debris?

Orbital debris is any man-made object in orbit about Earth which no longer serves a useful purpose.

What are examples of orbital debris?

Derelict spacecraft and upper stages of launch vehicles, carriers for multiple payloads, debris intentionally released during spacecraft separation from its launch vehicle or during mission operations, debris created as a result of spacecraft or upper stage explosions or collisions, solid rocket motor effluents, and tiny flecks of paint released by thermal stress or small particle impacts.

How much orbital debris is currently in Earth orbit?

More than 22,000 objects larger than 4 inches (10 cm) are currently tracked by the U.S. Space Surveillance Network. Only about 1,000 of these represent operational spacecraft; the rest are orbital debris. The estimated population of particles between .4 inches and 4 inches (1 to 10 cm) in diameter is approximately 500,000. The number of particles smaller than .4 inches (1 cm) probably exceeds tens of millions. [Video: The Expanding Danger of Space Debris]

Are orbital debris uniformly distributed about the Earth?

Most orbital debris reside within 1,250 miles (2,000 km) of Earth's surface. Within this volume, the amount of debris varies significantly with altitude. The greatest concentrations of debris are found near 500-530 miles (800-850 km).

How fast are orbital debris traveling?

In low Earth orbit (below 1,250 miles, or 2,000 km), orbital debris circle the Earth at speeds of between 4 and 5 miles per second (7 to 8 km/s). However, the average impact speed of orbital debris with another space object will be approximately 6 miles per second (10 km/s). Consequently, collisions with even a small piece of debris will involve considerable energy. [Related: How Much Junk is in Space?]

How is the International Space Station protected against orbital debris?

The International Space Station, or ISS, is the most heavily shielded spacecraft ever flown. Critical components such as habitable compartments and external high pressure tanks normally will be able to withstand the impact of debris as large as .4 inches (1 cm) in diameter. ISS also can maneuver to avoid tracked objects. ISS executes a collision avoidance maneuver once a year on average.

How long will orbital debris remain in Earth orbit?

The higher the altitude, the longer the orbital debris will typically remain in Earth orbit. Debris left in orbits below 370 miles (600 km) normally fall back to Earth within several years. At altitudes of 500 miles (800 km), the time for orbital decay is often measured in decades. Above 620 miles (1,000 km), orbital debris normally will continue circling Earth for a century or more.

Is re-entering debris a risk to people and property on Earth?

A significant amount of debris does not survive the severe heating which occurs during re-entry. Components which do survive are most likely to fall into the oceans or other bodies of water or onto sparsely populated regions like the Canadian Tundra, the Australian Outback, or Siberia in the Russian Federation. During the past 50 years an average of one cataloged, or tracked, piece of debris fell back to Earth each day. No serious injury or significant property damage caused by re-entering debris has been confirmed.

What can be done about orbital debris?

The most important action today is to prevent the unnecessary creation of additional orbital debris. This can be done through prudent vehicle design and operations. Cleaning up the environment remains a technical and economic challenge that is currently being investigated by the United States and other countries.

What is the U.S. policy on orbital debris?

Since 1988 the official policy of the United States has been to minimize the creation of new orbital debris. The most recent National Space Policy (June 28, 2010) contains a section entitled "Preserve the Space Environment" that addresses orbital debris mitigation for both the near term and long term. In 2001 the United States adopted a set of measures for government agencies and departments called orbital debris mitigation standard practices. These standard practices became the foundation for the development of international orbital debris mitigation guidelines.

Do other countries have guidelines on orbital debris?

Yes, Russia, China, Japan, France, and the European Space Agency have all issued orbital debris mitigation guidelines. In addition, in 2007 the United Nations, through its Committee on the Peaceful Uses of Outer Space, created a set of orbital debris mitigation guidelines.

Where can I read more about orbital debris?

Visit the NASA orbital debris website at www.orbitaldebris.jsc.nasa.gov.

Wednesday, September 7, 2011

NASA Needs More Astronauts, Report Says

From Fox News.com: NASA Needs More Astronauts, Report Says
The United States must maintain a strong astronaut corps, even though human space flight has been temporarily stalled for NASA and many astronauts have retired or quit this year, argues a new report from the National Research Council (NRC).

Over the years, the number of astronauts employed by NASA has clearly been downgraded — from about 150 in 1999 to 61 in 2011. And after several meetings with NASA representatives, former shuttle pilots and mission specialists, and representatives from private space companies, the NRC warns that 61 astronauts may not be enough.

We need new astronauts more than ever, it argues.

“The shuttle program was only one requirement for astronauts,” Joe Rothenberg, one of the co-chairs for the report, told FoxNews.com. “The most obvious one now is to continue operating the International Space Station. We have a partnership with the Russian Federal Space Agency, the European Space Agency and the others that developed it, and we have a commitment to operate it until 2020, staffing it with qualified astronauts to do research.”

In addition to maintaining the ISS, the report listed other jobs for which astronauts are needed, including the development of the next generation of human space flight vehicles. Whether it be for NASA’s Orion Space Capsule or commercial space flight vehicles developed by private companies like SpaceX, astronauts will need to be involved in both the development and operation of these vehicles.

From the various meetings and researched conducted with NASA and other space flight agencies, the report’s committee developed a formula to determine the absolute minimum number of astronauts needed in the post shuttle era.

“The astronaut model maintains a model of the basic operational duties, number of backups needed, the number of years it takes to train them” — the typical training program takes two to two and a half years — “and the annual nutrition you expect over the next five years,” Rothenberg told FoxNews.com. “That all goes into a model the committee uses, and then we basically have a sound way of projecting the size of the corps needed to execute the committees.”

NASA currently has 61 astronauts. The report argues that's just not enough. A NASA spokesman told FoxNews.com that the report was "helpful," but he did not address its major critique.

“The National Research Council report offers helpful advice about the appropriate size of our astronaut corps as we enter this exciting new era of space exploration and crew transport operations," said Michael Curie, a spokesman for the space agency. "It also provides guidance on the use of existing NASA facilities and other resources to train for future missions, and supports the role and definition of the astronaut corps in connection with the full utilization of the International Space Station.”

A major concern in the report revolves around the need for contingency plans. Rothenberg references the need for extra astronauts in case of unexpected developments that NASA can’t anticipate, such as the bicycle accident that prohibited astronaut Tim Kopra from flying the final flight of Discovery or the tragic shooting of Representative Gabrielle Giffords that led astronaut Mark Kelly to re-evaluate his ability to fly the shuttle.

“It’s not as easy in the last stages to fly ... with the size of the astronaut corps as it is now,” Rothenberg told FoxNews.com. “If we want to maintain our presence in human space flight and lower earth orbit, then there’s clearly not enough astronauts currently in the plan.”

The report notes that a ground crew of astronauts, such as those who train with the T-38N Talon two-seat training aircrafts, is just as important as those who work in space. By responding to emergencies on Earth, astronauts can develop the response skills needed when working in the high-stress environment of lower Earth orbit or the surface of the moon.

Overall, Rothenberg feels that a strong astronaut corps is a necessity for NASA so as to not waste the accomplishments it has made thus far.

“We have developed what I would call a pretty rigorous training program for astronauts,” Rothenberg told FoxNews.com. “That investment and the training required for it is a valuable national asset. It cost probably in the multiple billions of dollars over the past fifty years for the want of four or five extra astronauts. People don’t want us to spend money, but they are also the same ones that don’t want us to become a third world power in terms of space flight.”

“If we throw [the astronaut corps] away now, the cost would be so prohibitive, we’d stay on the ground forever.”

Tuesday, September 6, 2011

SpaceX, Blue Origin, And The Race To Control The Commercial Space Industry

From Fast Company.com: SpaceX, Blue Origin, And The Race To Control The Commercial Space Industry
A Soyuz rocket recently failed--surprising news, as it's generally considered a rather reliable rocket. In the process it pitched tons of vital food, engineering, fuel and air supplies for the International Space Station into the wastelands of Siberia. And at high speed--the ISS may have to be unmanned for a short interval as a result, despite billions of dollars and decades of effort. In the post-Shuttle era, this event is critical: It puts extra emphasis on the emerging commercial space industry.

SpaceX
SpaceX is the most high profile of the new pretenders to the space launcher crown, having had numerous successful trial launches of its Falcon line of medium-lift rockets. It's a fairly high-profile company, and some of this is helped by the fact its CEO is none other than Elon Musk, the man behind Tesla cars. The public success of SpaceX is only likely to grow in the coming weeks: NASA has recently given the company the green light to merge two of its future planned trial flights of its Dragon cargo capsule into one single flight. That's amazingly significant, since it means as well as flying up to and approaching the ISS under its own control, the SpaceX Dragon is now permitted to actually mate with one of the ISS's docking rings. That will be an important, historical moment.

SpaceX is busy prepping the Dragon capsule for this flight, and just a few weeks ago carried out an important propellant-loading test for the Falcon 9 rocket that'll propel the capsule into orbit in November. The company has recently revealed it's working on eight separate Dragon capsules in its development facility, and has plans to eventually shrink the production schedule from three months to six to eight weeks--depending on requirements. It also has highly-developed plans to build a crew-carrying version of the capsule, which could easily become the first commercial space lift to put astronauts aboard the ISS.

Late in August, Florida authorities approved an extra $7 million in funding to help SpaceX develop its launch facilites in the state, in an attempt to boost the potential launch rate of Falcon vehicles and bring perhaps hundreds of jobs with the effort. Given local high-tech job losses caused by the wind-up of NASA's Space Shuttle operations, this will be seen as a measure of how the commercial space industry can replace some of NASA's future missions.

Blue Origin
Blue Origin is much more secretive than SpaceX, despite the fact that it, too, has a charismatic billionnaire at the helm: Amazon's Jeff Bezos. The company has revealed very little about its plans thus far, apart from vague information about its vehicles--dubbed Blue Shephard, they're designed to launch and land vertically on retractable legs like the very best props from 1950s sci-fi TV shows.

Last week however, Bezos made an uncharacteristic public statement about a serious test failure of a Blue Shepard that had occured a week before. The pod--shaped like a headache pill, rather than a traditional rocket--had been taking part in a highly successful launch test. It had passed the speed of sound, and reached Mach 1.2 at 45,000 feet in altitude before the vehicle detected it was veering off trajectory, and thus terminated itself to prevent endangering lives on the ground below.

The company is already working on the next prototype, which at least explains what's going on in its 280,000 square foot facility in Kent. In April NASA awarded $22 million to the company to help it develop its rocketry systems, which may include a crewed capsule for future manned spaceflight in orbital operations, and a push-rocket launch abort system.

Orbital Sciences
Orbital Sciences ranks close behind SpaceX in readiness for serious-scale commercial spaceflight operations to suply the ISS. Last week the FAA awarded the firm a license to launch its rocket system--a Taurus II rocket carrying the firm's Cygnus capsule--from NASA's Wallops Island facility for a rendezvous with the ISS. The mission, scheduled for February, will mark similar Commercial Orbital Transportation Services contracts with NASA as SpaceX is carrying out. The firm also applied for a license to test its Taurus/Cygnus stack later this year with a dummy Cygnus--that's still pending.

NASA is helping the firm revamp its Wallops facility for the launches, and a first test flight at the location is currently scheduled for December.

Meanwhile Orbital, which has been building sattelites under contract for years, just won a $135 million contract to build the Ice, Cloud and Land Evaluation Satellite-2 (ICESat-2) for NASA. The vehicle is a climate change observation tool, but the contract and cash award will definitely aid Orbital's greater spaceflight plans, which include a manned variation of its capsule.

Virgin Galactic
Though it's a strictly suborbital operation, destined mainly for space tourism, Richard Branson's Virgin Galactic is the poster-child of the new commercial space business. Its hardware team, the famous Scaled Composites, were behind the first non-governmental man in space (winning the X-Prize with its SpaceShipOne vehicle) and a variation of this vehicle is going to be the mainstay of Virgin Galactic's operations.

The company also recently won a contract from NASA to carry out space science launches--leveraging the super-quick turnaround time offered by a Galactic flight to optimize the design of experiments that may later go on to become full-scale ISS-based ones.

As of today phase one of its spaceport in New Mexico, the world's first such commercial venture, is 90% complete, and will be finished within a few months. The second phase is already under construction and will also be finished ahead of first commercial launches in 2013. Much speculation has surrounded the company about its greater orbital ambitions, which may see it operating in the same market as SpaceX and Orbital--funded by its space tourism business. The company certainly has the financial and business backing to make the plans work.

Friday, September 2, 2011

Seattle scored just behind space shuttle winners

From Seattle PI: Seattle scored just behind space shuttle winners
Seattle finished fourth or fifth in the scoring to determine who would get three available space shuttle orbiters, according to a new report from NASA’s inspector general.

NASA offered up the retiring orbiters Enterprise and Atlantis, and the atmospheric test shuttle Enterprise. The Smithsonian Air and Space Museum now has Enterprise but was already slated to get Discovery.

The space agency got expressions of interest from 29 institutions and deemed 13 eligible. It evaluated them using a system that awarded points for:

* Commitment to funding for moving and displaying the shuttle;
* Risk to having the funding ready;
* Availability of a facility for the shuttle;
* Ability to move a shuttle from a local airport to the site;
* Ability to meet NASA’s delivery schedule;
* Annual attendance;
* Regional population;
* International access (based on tourism);
* Museum certification or accreditation.

Here are the 13 institutions, with their point totals:

* California Science Center, in Los Angeles, 90;
* Intrepid Sea, Air, and Space Museum, in New York, 85;
* Kennedy Space Center, in Cape Canaveral, Fla., 85;
* The Museum of Flight, 80;
* National Museum of the U.S. Air Force, in Dayton, Ohio, 80;
* Adler Planetarium, in Chicago, 75;
* San Diego Air and Space Museum, 75;
* March Field Air Museum, in Riverside, Calif., 75;
* Evergreen Aviation and Space Museum, in McMinnville, Ore., 70;
* Space Center Houston, 60;
* Tulsa Air and Space Museum & Planetarium, inTulsa, Okla., 60;
* U.S. Space and Rocket Center, in Huntsville, Ala., 60;
* Brazos Valley Museum of Natural History/Bush Library and Texas A&M, in College Station, Texas, 40

NASA awarded Endeavour to the California Science Center, Enterprise to Intrepid and Atlantis to Kennedy Space Center.

The Museum of Flight got top marks for everything but international access (where it got the lowest of three possible marks, attendance (second-lowest of four possible scores) and regional population (middle of three marks).

But the inspector general’s office found that NASA erroneously gave the Air Force Museum five points instead of 10 for transportation risk, meaning it should have tied with Intrepid and Kennedy Space Center, and finished ahead of the Museum of Flight.

Informed of the mistake, NASA Administrator Charles Bolden told inspectors he would have made the same choices if he knew the Dayton museum tied with Intrepid and Kennedy, “because the Air Force Museum was unable to commit to raising the $28.8 million required to reimburse NASA for an Orbiter and because the Intrepid and the Kennedy Visitor Complex had larger regional populations and better access for international visitors.”

The inspectors said they found no evidence that the NASA review team’s recommendation or Boldin’s decision “were tainted by political influence or any other improper consideration.”

They said NASA should

* Expeditiously review recipients’ financial, logistical, and curatorial display plans to ensure they are feasible and consistent with the Agency’s educational goals and processing and delivery schedules;
* Ensure that recipient payments are closely coordinated with processing schedules, do not impede NASA’s ability to efficiently prepare the Orbiters for museum display, and provide sufficient funds in advance of the work to be performed;
* Work closely with the recipient organizations to minimize the possibility of delays in the delivery schedule that could increase the Agency’s costs or impact other NASA missions and priorities.

Thursday, September 1, 2011

David Bowie’s ‘Space Oddity’ Becomes a Children’s Book

From Ultimate Classic ROck: David Bowie’s ‘Space Oddity’ Becomes a Children’s Book
The lyrics of David Bowie‘s 1969 classic ‘Space Oddity’ have been used as the basis of a colorful, if somewhat scary, illustrated children’s novel by artist Andrew Kolb.

A .pdf of the entire book can be downloaded for free at Kolb’s website. (Which as of today, Aug. 29, seemed to be a little difficult to load due to excessive traffic.) In just under 40 pages, the book tells the story of brave astronaut Major Tom, who launches himself into space and wins the adoration of the press reporters down on earth.

Then, he explores even further with a space walk, only to watch his craft suffer critical damage from a meteor storm, leaving him trapped in space with time to send just one final message of love down to his wife.

Of course, as Badass Digest points out, that’s just one possible interpretation of Bowie’s lyrics. Many people believe it’s not an accident, but choice that sends Tom out alone into the great beyond. The thinking goes that after seeing the beauty of space, he decides to leave Earth and all its problems behind once and for all.

Regardless of how it is meant to be taken, ‘Space Oddity,’ which was a hit immediately in England but didn’t take over the airwaves in America until a 1972 re-issue, has gone on to become of of Bowie’s signature songs. U2 used the song on their last tour as the soundtrack for their “360″ stage coming to life at the start of each concert.

Speaking of brave explorers disappearing into the outer regions, the author of the recent David Bowie biography ‘Starman’ has gone on record as saying he doubts we’ll ever hear new music from the “Thin White Duke” ever again.

Wednesday, August 31, 2011

Extraterrestrial Hurricanes: The Most Monstrous Storms Happen in Space

From Fox News: Extraterrestrial Hurricanes: The Most Monstrous Storms Happen in Space
By Earth standards, Hurricane Irene is a monster storm. But it's just a baby compared to the massive cyclones of Jupiter and Saturn.

Our planet is not the only one in the solar system that boasts huge, hurricane-like storms. The gas giants Jupiter and Saturn, for example, churn out spinning squalls that can be bigger than the entire Earth. While these storms aren't fed by warm ocean water the way terrestrial hurricanes are, they're similar in a lot of ways, scientists say.

"There certainly are storms that have thunder and lightning and rain that are bigger than terrestrial hurricanes," said atmospheric scientist Andrew Ingersoll of the California Institute of Technology, a researcher with NASA's Cassini mission to Saturn. "And more violent — the winds on those planets are stronger, too." [Photos: Most Powerful Storms of the Solar System]

Giant planets, giant storms

Hurricane Irene measured about 600 miles (966 kilometers) across as it bore down on the U.S. East Coast today (Aug. 26).

That's big and scary, but it pales next to storms on our solar system's gas giants. Jupiter's Great Red Spot — which has been raging continuously for at least 180 years — could fit two entire Earths within it, Ingersoll said.

And in December, a thunderstorm about 6,200 miles (10,000 km) wide erupted on Saturn. This one, known as the Great White Spot, is still going strong, and some of its clouds have wrapped all the way around the ringed planet. [Top 10 Extreme Planet Facts]

The Great White Spot also generates lots of lightning, just like thunderstorms here on Earth.

"We can see the lightning flashes on the night side, and we can hear the radio static from the lightning," Ingersoll told SPACE.com. "The energy in the lightning flashes is a lot stronger than terrestrial lightning."

Further, last year, astronomers spotted a cyclone at Neptune's south pole that was thousands of miles wide. The Neptune squall was similar to a spinning storm discovered a few years earlier at Saturn's south pole, which even had a well-developed eye, just like an Earth hurricane.

But the Saturn polar vortex was much bigger than any hurricane found on Earth. Its eye alone measured about 2,500 miles (4,000 km) in diameter; the eye of a typical terrestrial hurricane may be just 2 or 3 miles across.

Energy and moisture

Here on Earth, hurricanes gain their power from warm ocean water.

Warm, moist air over tropical or subtropical seas rises, causing a zone of lower air pressure beneath it. Higher-pressure air zips in to fill the void. But that air soon warms, becomes moist and rises, too. As this pattern repeats, a huge, swirling storm is born.

Jupiter and Saturn don't have oceans, so their spinning storms aren't "hurricanes" in the strict, terrestrial sense. But similar processes spawn them, according to Ingersoll. [Photos: Jupiter, Largest Planet in the Solar System]

"Heat makes buoyancy; hot air rises," Ingersoll said. "Heat also causes evaporation of moisture, and when the moisture condenses and forms rain, that releases the energy. So, energy and moisture."

Most of the energy driving Earth's hurricanes ultimately comes from the sun. But that may not be the case on Jupiter and Saturn, which orbit our star from much farther away than Earth does.

"They're so giant that they still have retained some of their heat of formation," Ingersoll said. "So they have their own internal heat that can generate these giant storms."

The moisture requirement explains why gigantic, hurricane-like storms don't seem to occur on Venus or Mars, he added.

"The giant planets have moisture down below the clouds," Ingersoll said. "But Venus doesn't. Venus is dry as a bone, hot and dry. It's not comparable. And Mars is cold and dry."

Saturn storm mysteries

Saturn's Great White Spot tends to erupt every few decades, shattering long periods of calm and quiescence. Scientists still aren't sure why some storms on the giant planets should be so big, and so infrequent.

"For some reason, they store up that energy for a long time, then let it loose in a violent, huge storm," Ingersoll said. "It didn't have to work out that way; they could let off a little popcorn now and then. But they don't do that."

He's hoping that Cassini will help resolve this question — just one of many that scientists are grappling with as they try to understand the weather systems on other planets.

"We're working right now on this giant Saturn storm, with that exact question in mind," Ingersoll said.