Tunguska

A hundred years ago today, something crashed into the forest of Siberia. Or not-- at least one scientist argues a huge natural gas explosion did the deed. Uncertainty has always surrounded the Tunguska Event, which leveled a huge expanse of forest and brightened the night sky as far away as London. The fact that the incident site was off-limits to Western science for decades during the Soviet period clearly fueled the mystery.

The consensus today is that a small asteroid exploded deep into Earth's atmosphere that day. Latest estimates are that the explosiom may not have been quite as powerful as first thought, and that the body was smaller, perhaps only 56 feet in diameter. Some scientists argue it was a comet, not an asteroid. (Other scientists would say there's likely no difference between asteroids and comets stripped of their volatiles.)

Whatever caused the destruction at Tunguska, it's likely a reminder that Earth has been struck by objects from space in the past, and, barring intervention, will be again. A Tunguska level event could destroy a major city.. A bigger body could reach the ground and be even more catastrophic. There are a few small prohects around the world looking for potentially dangerous objjects in space, but, so far, finding them and creating ways to deflect them away from Earth has not been a priority. That's gambling with the future of humanity. It's a bet we may well win, but we should understand that's what inattention in this area is doing.

The Shuttle Era

The Discovery Channel's When We Left Earth covered the space shuttle era last night. For all the public and media indifference to shuttle flights over the years, the documentary reminds us what a remarkable flying machine the shuttle is. Thirty years out, there's still no other spacecraft in the world that comes close to the shuttle's capabilities.

Perhaps the dramatic high point of the shuttle program was the repair mission to the Hubble Space Telescope. NASA had launched Hubble-- a huge, expensive science project-- only to discover the lens system was faulty. The agency that had accomplished the legendary feat of putting men on the Moon was in danger of becoming just another federa; bureaucracy that couldn't get anything right. More than the future of astronomy was riding on the dangerous and demanding repair mission. Extraordinary film clips helped tell the story of the repair mission that saved Hubble and gave NASA back its can-do spirit and image.

Ironically, the next shuttle mission will be the last servicing mission to Hubble. After the Columbia tragedy, NASA at first decided not to fly another mission to Hubble, saying it was too dangerous, but the outcry from the public and the science community led to a reversal of that decision.

Another Phoenix Discovery

NASA announced yesterday that the first chemical analysis of Martian dirt done in the lab of the Phoenix Mars Lander produced some interesting results. The dirt contained several soluble minerals, including potassium, magnesium, and chloride-- all of which are found in living systems as well as in nonbiological settings.

Coupled with Phoenix' earlier discovery of water ice just under the surface, the dirt analysis brings the possibility of life on Mars one step closer. The surface of Mars is pounded by lethal radiation from the Sun, but subsurface life seems a real option. Phoenix, however, may or may not be able to find any life or evidence of life. Still, after all these years, it's possible the only thing separating humanity from absolute proof that life exists elsewhere in the universe is a column of Martian dirt a few meters deep directly under Phoenix.

Chesapeake Blast

An asteroid struck Earth 35 million years ago, creating the depression that was eventually filled with water and became Chesapeake Bay. The impact and subsequent firestorm killed off most life in the area. Most, but not all.

Researchers have recently found that some microbes survived the disaster. They were living deep undergound-- deep enough not to feel the full force of the heat generated by the impact. Researchers also believe other microbes recolonzed the area relatively quickly after the event.

Such findings emphasize how difficult it seems to be to eradicate life after it has established itself. Periodic extinctions have threatened life on Earth, but nothing has yet delivered the knockout blow. Indeed, life has been incredibly resilient, bouncing off each extinction and creating arrays of magnificent and complex forms.

Resilience augurs well for finding life on other worlds. If life established itself on a more hospitable early Mars, for example, odds might be good that it endured long enough to leave evidence we can find. It may even still exist.

Mars Slammed?

Astronomers have long known that the northern hemisphere of Mars was low and fairly flat, while the southern was higher, rougher, and heavily cratered. Explaining how that came to be, however, has been a problem.

New studies suggest an extremely violent cause. A rock one half to two thirds the size of Earth's Moon slammed into Mars about 3.9 billion years ago, creating what the proponents of this theory say is the largest impact basin in the Solar System, covering about 40 percent of the surface. It is so large, they say, that no one recognized it for what it is until recently. Computer models of both the theoretical impact and the internal structure of Mars seem to support the impact hypothesis.

If this new theory is correct, Mars was slammed at roughly the same time a Mars-sized object probably collided with Earth. The ejecta from that collision eventually formed the Moon.

Yummy Mars Dirt

Now that the Phoenix Mars Lander has established water ice exists near the Martian surface, it is about to taste the dirt.

Over the next few days, the robot arm will scoop up some dirt and deliver it to the automated lab. There, the dirt will be mixed with water brought from Earth, heated, and chemically analyzed to give scientists a clear picture of what actually makes up the soil of the Martian arctic.

Of course, during such testing, biological markers could also be discovered.

Tomatoes, Salmonella, and Spacehab

The recent problem with salmonella-carrying tomatoes could turn out to be an early boost for the industrialization of space.

Spacehab, Inc., is a small company that flies scientific experiments on shutle flights and ISS-- when it can. Other companies would like to fly experiments, but acquiring the space onboard is difficult. Spacehab was able to get a salmonella experiment onboard the most recent shuttle flight, just as the story about salmonella in commercially grown tomatoes was breaking. Early results from that study will soon be on the way to FDA researchers.

If pharmaceutical research breaks out as a space industry-- usinng the environments of space and microgravity to give us insights that we couldn't get on Earth-- it could be the catalyst for private industry and investment to move into space in a big way. If it turns out certain drugs can only or best be produced in microgravity, humanity will be finally and firmly on the road to creating a spacefaring civilization.

When We Left Earth

The Discovery Channel has been offering the documentary series about NASA's manned spaceflight program, When We Left Earth, over the past week. Last night's two-hour program covered Apollo and Skylab.

Some stories need a writer to shape and present them in a dramatic fashion; others just need a writer who won't mess them up. The story of the early days of space exploration definitely fits in the latter category. Last night's episode was a good example. The story of Apollo was told largely by the astronauts who flew the missions and the flight directors who led the effort at Mission Control. It featured remarkable footage shot during the missions. One interesting tidbit told by Gene Cernan concerned Apollo 10, which was a dress rehearsal for Apollo 11. At the time, there was some speculation that Apollo 10 might actually attempt a landing, but Cernan said that would've been impossible because the fuel in the lunal module's ascent stage was shorted. Had they landed, they would not have had the fuel to lift off. Perhaps NASA hadn't wanted to tempt Cernan and mission commander Tom Stafford.

As Jim Lovell and flight director Gene Krantz say, the push to meet President Kennedy's challenge to put a man on the Moon and return him safely to the Earth before the decade of the 1960s was out shows what humans can accomplish if we put our minds to it. That example is relevant to endeavors other than exploring space.

Ice Found By Phoenix

"It must be ice." That's the conclusion of Peter Smith, principal investigator of the Mars Phoenix Lander. He based that conclusion on a Martian disappearing act. The Phoenix robotic arm dug a trench in the soil a few days ago and uncovered clumps of whitish material. Scientists couldn't decide whether the stuff was salt or water ice. Imaging the trench again a few days later, after the clumps had been exposed to the sun's heating-- the clumps were gone. Water ice vaporizes on Mars when exposed to heat. Salt does not.

So, Phoenix has already made a major discovery. Water, in the form of ice, seems to exist over much of subsurface Mars. Earlier, NASA's rovers had found evidence of water nearer the equator. Easily accessible water bodes well for future human exploration and colonization of the planet.

Of course, fairly abundant water also leaves open the possibility of life. Discovering evidence of past or current life on Mars may be the only bigger discovery Phoenix could make.

Stern To Odyssey Moon

Alan Stern, former chief of NASA's Science Mission Directorate and a power behind the New Horizon mission currently on its way to Pluto, is joining the executive team of Odyssey Moon.

Odyssey Moon fielded the first team to take up the Google Lunar X-Prize challenge, but OM has plans that go far beyond winning the race to put a privately funded and operated rover on the Moon. It plans, in fact, to be a participant in the next phase of lunar exploration, and to turn a profit in the doing.

Stern will be an exclusive part-time employee, and will consult on OM's lunar science package.

Planet X... Again

Studying perturbations in the orbit of Uranus led to the discovery of Neptune in 1846-- a spectacular confirmation of Newtons's Laws of Gravity. A similar search for another "Planet X" even farther out led to the discovery of Pluto in 1930. Pluto, it turned out, wasn't big enough to gravitationally affect much of anything, and the oddities in Neptune's orbit were eventually explained in other ways. The universe can be subtle.

Now, a team of Japanese researchers are calling for another search for Planet X. They say the peculiar orbits of some Kuiper Belt objects-- bodies that orbit the Sun beyond Pluto-- can best be explained by a large body in an orbit 100-200 times the Earth-Sun distance. They calculate the body would be between 30-70 percent of Earth's mass, which would make it Mars' size or larger, but smaller than Venus.

Such a world, if it exists, would likely be made mostly of rock-hard water ice. That kimd of huge water resource, conveniently in one place, could well eventually be humanity's last base in the Solar System before we head to the stars.

Phoenix Lander Update

The first sample of Martian soil heated and analyzed by the science suite on Phoenix showed no sign of water. Not a trace. Mission scientists believe, however, that the lack of water is due to the fact that the sample laid atop the Lander for several days, exposed to the sun's heating, while scientists tried to get some of it to fall into their oven. They plan to heat the sample to higher temperatures, still hoping to find water's signature. The scientists are also confident of finding water in subsequent samples.

There's every reason to think they will succeed. NASA's rovers, Spirit and Opportunity, have found evidence of water near the surface, and subsurface radar has revealed a huge area of water or water ice under Mars' north polar region. Phoenix sits atop that area.

The biggest discovery of the Phoenix mission so far is a layer of white material just under the surface. NASA is unsure as yet whether the material is ice or salt.

IAU Revisits Pluto

Last week, the International Astronomical Union, the governing organization of the world's astronomers, decided to call Pluto a "plutoid." In 2006, the IAU stripped Pluto of its status as a planet. An element in that decision charged the IAU with the task of coming up with another name for Pluto and similar objects-- hence plutoid. Most planetary astronomers think Pluto is simply the first discovered of hundreds of similar bodies.

Many astronomers, however, argue that's no reason to say Pluto isn't a planet. They see nothing wrong with a Solar System having hundreds of planets. Indeed, the controversy concerns what should be the correct definition of "planet," and that battle shows no sign of resolution. Humans, even intelligent ones, will argue about the strangest things.

One other strange aspect to this debate is that the 2006 decision demoting Pluto limited itself to this Solar System; whatever orbited other stars was not addressed. Astronomers and physicists have spent literally centuries doing the hard work of theorizing and amassing evidence that allows humans to make the rather remarkable assertion that the physical laws that operate on Earth are the same laws that operate everywhere in the universe. The IAU decision to treat our Solar System as somehow special seems to fly in the face of astronomy's greatest and most profound discovery. But that's the subject of another debate.

Discovery Home Safely

Ending a near-perfect mission with a textbook landing yesterday, space shuttle Discovery returned safely to Cape Kennedy.

There are now only ten more planned shuttle missions. The next one will be the final Hubble repair mission, slated for October. After the Columbia tragedy, NASA had cancelled that mission as being too dangerous, but pressure from the science community and the general public led NASA to reinstate the flight. The remaining flights will focus on supplying and finishing construction of ISS before the shuttle is retired in 2010. That will require a fairly aggressive flight schedule. There is a possibility that Congress could extend the program for a year or so, but the budgetary implications of such an extension for NASA's other programs could easily be negative.

At some point, the U. S. will have to move beyond the shuttle. It's probably best not to drag that move out any longer.

STS-124 Coming Home

Space shuttle Discovery has undocked from ISS and is scheduled to land back in Florida tomorrow.

There was a slight stir earlier this morning when NASA reported something following the shuttle. Alas, it wasn't an alien ship-- that would've been much more exciting. Rather, it was a metal clip that has come off the orbiter's tail. NASA says the clip poses no risk to the shuttle or its crew.

Phoenix Starts Work

After a few days of fiddling, a soil sample was delivered to the oven of the Phoenix Mars Lander. Over the next several days, the oven will be heated and chemical analysis of the soil will be carried out.

The robot arm of the Lander delivered the sample to the the screen above the oven a few days ago, but the soil proved to be clumpier than scientists imagined, and none of the sample fell through the screen. Several sessions of vibrating the screen seem to have finally loosened up the sample enough so that some of it fell through the screen and into the oven.

Phoenix is ultimately searching for evidence of life on Mars. If it finds such evidence and plops it down smack in the middle of the U. S. presidential campaign, it'll be interesting to see the effect that has on U. S. space policy.

Big Day For SA

Space Adventures has made not one but two major announcements today. One is the formation of the Orbital Mission Explorers Club, which will allow members to reserve a place on a future spaceflight for a $5 million down payment. That's good for a busy person who nonetheless wants to fly into space someday, and, of course, its good for SA's financial position. Sergei Brin, co-founder of Google, has become the founding member of the club. An interesting twist is that people who reserve a position are then free to sell that reservation. Perhaps the beginnings of a market?

The second major announcement involves ISS. In 2011, SA will fly two private travelers on the same Soyuz-- a special Soyuz is being built for the flifght-- to ISS in the first private spaceflight to the space station. SA, therefore, continues to broaden its offerings and strengthen its balance sheet, which should allow it to pursue even more ambitious projects.

With Space Adventures, already the leader in space tourism, making such a double splash, perhaps marking a turning point in private industry's involvement in space commerce and development, watching the evening news broadcasts to see what kind of coverage-- if any at all-- they give to SA's announcements should be interesting.

Detecting Extrasolar Moons

Finding planets orbiting other stars is still quite a challenge-- though 300 have been discovered so far. Still, some scientists are already looking at the next step: How might we find extrasolar moons?

The question has a bearing on the search for life. Virtually all exoplanets discovered to date, for example, are huge worlds that could easily have moons of substantial size. They are also mostly "hot Jupiters," orbiting their suns tightly. A giant planet only a bit farther out could have a moon-- a Titan, or even a Mars or an Earth-- that could support life.

Finding exomoons now could be done by building up an infrared picture of an exoplanet. Slowly, a body the size of Earth's Moon might make itself known as its own infrared signature was built up. A better option will come next decade, when NASA puts its space-based planet finders into operation. They will be able to image nearby Earth-sized planets directly, and, therefore, might also be able to directly detect very large moons. They may also be able to observe transits of moons-- that is, moons moving across the disk of their parent planet.

STS-124 Halfway Report

Everything is going well on STS-124. There seems to be no problem with damage of the orbiter's heat shield tiles, the new toilet has been successfully installed on ISS, and things are going smoothly with the installation of a much larger and more sophisticated piece of hardware, Japan's Kibo laboratory.

Kibo has its own robotic arm, which will allow astronauts to tend to experiments exposed to space on Kibo without doing a spacewalk. The arm was tested for the first time yesterday, and all went well.

The Kibo arm gives ISS two robotic arms. The Canadarm, however, is much larger and can be moved along the outside of the station, whereas Kibo's arm is fixed in its location on the Japanese module.

McCain On Space

Senator John McCain of Arizona, one of two fellows with the best chance to be the next president of the United States, has built a record in Congress supportive of NASA in general and of manned spaceflight in particular. During his presidential campaign, McCain has also expressed support for the Moon/Mars program intended to lead humanity into the Solar System to stay.

Recently, however, as a way of dealing with the federal budget deficit, the McCain campaign has embraced the idea of freezing discretionary spending in the budget for one year. That would presumably include NASA. If exceptions start being made in such an approach, the risk is that the entire policy would unravel as every program argued it should be exempted.

Freezing NASA's budget, though, would seem to delay development of the new hardware necessary to replace the space shuttle and carry out the Moon/Mars program. It would likely increase the time astronauts would be dependent upon the Russian Soyuz for access to space-- a situation McCain has decried. How President McCain would thread the space needle, therefore, is unclear.

Smallest Exoplanet Yet

A team led by David Bennett of the University of Notre Dame has found the smallest planet outside of our Solar System yet. It's 3,000 light-years away, and it orbits what is likely a brown dwarf-- a star that doesn't have quite enough mass to achieve sustained nuclear fusion.

With roughly three times the mass of Earth, the world is a "super-Earth." Scientists believe it has a thick atmosphere, and may be covered by an ocean of water. It orbits the brown dwarf at about the same distance that Venus orbits the Sun. Even though the brown dwarf gives off minimal heat, scientists believe radiating internal heat could make surface temperatures on the planet fairly mild.

Brown dwarfs have not been thought to be good bets to harbor planets. The fact that at least some do is one more reason to believe planets are common throughout the cosmos.

Phoenix Update

NASA has been carefully checking out the Phoenix lander since it successfully touched down on Mars. Now, the good stuff is about to begin.

Perhaps today, the robot arm on the lander will dig into the soil-- assuming everything works as planned-- scoop up a sample, and deposit it in the automated lab, where the sample will be chemically analyzed. That procedure will hopefully take place several times during the planned 90 day mission of Phienix. NASA also hopes the arm can get down to the subsurface ice in the polar regions.

Of course, learning about a planet from one site has its limitations. An alien probe that landed in Kansas could not extrapolate the Amazon rain forest, or the ocean depths-- possibly not even the Rockies. Phoenix, however, is one approach among several going on simultaneously to understand Mars. Therein lies its value.

Useful Lunar Dust

As recently reported in this blog, NASA is grappling with ways to control dust around a future lunar base. The stuff tends to get in everything in the low lunar gravity-- including, for example, astronauts' lungs, which could pose a long-term health risk. It turns out, however, that the dust may also have its uses.

NASA Goddard is working on a way to use lunar dust as a major component in concrete manufactured on the Moon. Using lunar dust would mean that component of the mix wouldn't have to be brought from Earth. Such concrete could be used to build habitats, or possibly huge optical telescopes. Coating a concrete form in a parabolic shape with aluminum would create a highly reflective surface for a telescope not only several times larger than its Earthly counterparts, but one with a solid, stable base under constantly dark skies unbothered by atmospheric antics.

Such building projects wouldn't take up all the dust, of course, but it would turn a menace into a combination menace and resource.

Another Alien Video?

According to AOL News, a man in Denver says he has video of an alien looking into a window of his home. A still shows a whitish image. The image seemed to a be a large rounded head with large eyes. In another context it could be called ghostly. The approximateky three minute long video will be the centerpiece of a television documentary to air later this year.

Of course, this wouldn't be the first time a documentary based on a video purported to show aliens made a big splash. In the 1990s, film supposedly showing the 1947 autopsy of an alien recovered from the Roswell crash was the basis of a hugely successful documentary for FOX. That film has since been shown to be a hoax.

Will the Denver video create a similar stir? Will it, too, turn out to be a hoax? Stay tuned.

STS-124 Going Well

Space shuttle Discovery has arrived at ISS to begin the meat of the STS-124 mission, the installation of the second of three modules of Japan's Kibo lab.

Meanwhile, preliminary inspection of Discovery showed no obvious problems with the heat shield tiles. The external tank used in the launch was designed to limit the amount of foam that would break off, and the new design seems to have worked. NASA is still carrying out more detailed analysis of both the tank and the orbiter, however.

STS-124 On Orbit

A beautiful launch late Saturday afternoon began the mission of STS-124. The main objective of the mission is to deliver the second of three modules that comprise Japan's Kibo laboratory to the ISS. This module will add substantially to the living space aboard ISS, which will be important when the size of the ISS crew doubles from three to six.