NASA

Among the spaceship projects receiving NASA support are Boeing Co.'s CST-100 capsule (left), Sierra Nevada Corp.'s Dream Chaser space plane (middle) and SpaceX's Dragon capsule (right).

NASA has committed $1.1 billion over the next 21 months to support spaceship development efforts by the Boeing Co., SpaceX and Sierra Nevada Corp., with the aim of having American astronauts flying once more on American spacecraft within five years. 

The lineup of companies matches what sources told NBC News on Thursday, but today NASA laid out the details, including the outlays for each of the teams involved. The space agency is setting aside $460 million for Boeing, $440 million for SpaceX and $212.5 million for Sierra Nevada.

The next phase of NASA's commercial spaceflight effort — known as Commercial Crew Integrated Capability, or CCiCap — calls for these three companies to take their design and testing program through a series of milestones by May 2014. Optional milestones could lead to crewed demonstration flights in later years.

NASA wants to have at least one commercial space taxi carrying astronauts to and from the International Space Station by 2017. The three companies say they can meet or beat that schedule, provided that they continue to receive NASA support.

NASA Administrator Charles Bolden told reporters that the space taxi program "is a top priority of the Obama administration." In the wake of last year's retirement of the shuttle fleet, the space agency has had to depend on the Russians to fly American astronauts at a cost of roughly $60 milllion a seat. Bolden said the move to U.S. commercial transport would guarantee "that we never find ourselves in the situation where we find ourselves today," at the mercy of a sole provider.

Flying crew by 2015, 2016, 2017?
This is actually the third phase of NASA's Commercial Crew Program. All three companies have received NASA support adding up to hundreds of millions of dollars during earlier phases. Boeing is working on a capsule called the CST-100, SpaceX is upgrading its Dragon capsule to be capable of flying astronauts safely, and Sierra Nevada is testing its Dream Chaser space plane, which looks like a miniaturized version of the space shuttle.

The CST-100 and Dream Chaser would be sent into orbit on United Launch Alliance's Atlas 5 rocket, while SpaceX would launch the crew-capable Dragon on its own Falcon 9 rocket. The Dragon and Falcon 9 are already being used for robotic cargo resupply missions to the space station. 

The three companies say their spacecraft will be capable of flying seven astronauts to the space station, at a per-seat cost that's less than what NASA is paying the Russians.

NASA and congressional leaders made a deal that called for two commercial partners to receive full funding, with one additional backup partner receiving half funding. That would imply that Sierra Nevada Corp. is the halfway partner, but Mark Sirangelo, chairman of SNC Space Systems, said he didn't see it that way.

"We're very happy with the award," Sirangelo told me. "Obviously more money would have been great." He said NASA's funding, plus Sierra Nevada's own resources, would keep the program on track for the start of operations in 2016 or 2017. Sierra Nevada's milestones stop just short of a critical design review, while SpaceX and Boeing could be funded through that phase.

In a statement, Elon Musk, SpaceX's billionaire founder, CEO and chief designer, hailed the CCiCap award as "a decisive milestone in human spaceflight" that would set "an exciting course for the next phase of American space exploration."

"SpaceX, along with our partners at NASA, will continue to push the boundaries of space technology to develop the safest, most advanced crew vehicle ever flown," Musk said.

Boeing also welcomed today's announcement. "Today’s award demonstrates NASA's confidence in Boeing's approach to provide commercial crew transportation services for the ISS," John Elbon, Boeing vice president and general manager of space exploration, said in a statement. "It is essential for the ISS and the nation that we have adequate funding to move at a rapid pace toward operations so the United States does not continue its dependence on a single system for human access to the ISS."

SpaceX projects being able to launch a crewed demonstration flight in 2015, and Boeing anticipates achieving that feat by late 2016, said Phil McAlister, director of NASA's commercial spaceflight development program. However, he said those timetables come with a "big asterisk": optimal funding from NASA, which McAlister said almost never happens.

Musk told me that the 2015 demonstration flight would go into orbit, but not to the space station. He estimated that the first space station flight could take place a year later. Getting to that point would require NASA funding to the tune of $1 billion, he said — which implies that SpaceX would be roughly halfway there with the CCiCap funding.

A PDF file from NASA summarizes the details for the CCiCap agreements.

Who didn't win?
Four other companies submitted proposals for CCiCap funding, said Bill Gerstenmaier, NASA's associate administrator for human exploration and operations. Three of the also-rans — Space Operations, American Aerospace and Space Design — didn't meet the requirements for consideration, he said.

The fourth company was ATK, which has been working with Lockheed Martin and Astrium on the Liberty launch system. ATK has said that it will continue work on Liberty, which would use adapted versions of the space shuttle's solid rocket booster and a second stage from Astrium's Ariane 5 rocket. But without NASA support, the pace of development would be slower.

Gerstenmaier said ATK's development plan didn't come up to the level of the three companies that were selected, but held off on providing details about the decision process. "The stronger proposals were really the three that we talked about," he said.

Additional companies could negotiate unfunded agreements for NASA's advice, McAlister said. ATK and two other companies, United Launch Alliance and Excalibur Almaz, had such agreements during earlier phases of the commercial crew program. Another company, Blue Origin, has been received NASA funding for the development of its orbital space vehicle but did not apply for continued CCiCap support.

Looking ahead
NASA says the reliance on commercial transport to low Earth orbit would free up the space agency to concentrate on exploration beyond Earth orbit.

"For 50 years American industry has helped NASA push boundaries, enabling us to live, work and learn in the unique environment of microgravity and low Earth orbit," Gerstenmaier said in a statement. "The benefits to humanity from these endeavors are incalculable. We're counting on the creativity of industry to provide the next generation of transportation to low Earth orbit and expand human presence, making space accessible and open for business."

NASA is spending billions of dollars to develop the Orion multipurpose crew vehicle for deep-space exploration, as well as a heavy-lift rocket known as the Space Launch System. Those spacecraft are being designed to send astronauts to a near-Earth asteroid by 2025, and to Mars and its moons in the 2030s.

More about the space race:

• NASA backs Boeing, SpaceX, Sierra Nevada in space race
• Follow the money in the commercial space race
• Why SpaceX is setting the pace in the space race
• Cosmic Log archive on commercial space

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.

Even before its landing, NASA's Mars Science Laboratory has sent back its first scientific results — shedding light on the radiation exposure that astronauts would face during a future mission to the Red Planet.

The good news is that the spacecraft's protective shell, which is similar to the shielding being developed for NASA's Orion deep-space capsule, reduces the exposure inside the spacecraft to about a hundredth of what it was outside the spacecraft. That's according to Don Hassler, the principal investigator for the Radiation Assessment Detector that's installed on the MSL Curiosity rover.

The bad news is that the internal exposure levels measured during MSL's 8-month-plus cruise to Mars would still constitute "a significant contribution to an astronaut's career limit," Hassler said.

Hassler discussed the findings in general terms today during a pre-landing briefing conducted at NASA's Jet Propulsion Laboratory in Pasadena, Calif. The Mars Science Laboratory is due to plunge through Mars' atmosphere and lower Curiosity to the surface at 10:31 p.m. PT Sunday (1:31 a.m. ET Monday).

Mission managers said the probe was almost precisely on target for the landing in Gale Crater, within sight of a mountain that towers 3 miles (5 kilometers) above the crater floor. "I just can't wait," said Michael Meyer, the lead scientist at NASA Headquarters for the Mars exploration program.

Scientists say the layers that make up the mountain, known as Aeolis Mons or Mount Sharp, record billions of years of geological history — including the era when Mars was warmer, wetter and more conducive to life. The Curiosity rover's main task is to seek out the chemical evidence that could tell scientists whether Mars was ever potentially habitable. "What you've got here is really kind of a geologist's paradise," said Caltech geologist John Grotzinger, project scientist for Curiosity.

Preparing the way for humans
Although the habitability question is the $2.5 billion mission's top issue, Mars Science Laboratory will also gather data to help NASA prepare for eventual human missions to Mars. The early readings from the Radiation Assessment Detector, known as RAD, are part of that investigation.

NASA

An artist's conception shows the Mars Science Laboratory during its cruise phase, heading from Earth toward Mars. The spacecraft's protective shell is similar to the hull of a crewed spaceship.

RAD's readings are still being analyzed in advance of submission to a scientific journal, Hassler told me, but the exposure equaled "a few tens of percent" of NASA's career limit. And that's just for a one-way trip. Astronauts would face additional exposure during their work on Mars and on the return trip.

NASA's career limit for radiation exposure is in the range of 1 to 4 sieverts, depending on the age and gender of the astronaut. The space agency associates that level with a 3 percent excess risk of cancer. 

Space radiation has long been recognized as one of the biggest space hazards humans would face on long-duration trips beyond Earth's protective magnetic field, but the RAD results are expected to represent the best effort to quantify that hazard for Mars trips. RAD will continue to monitor radiation exposure on the Martian surface throughout Curiosity's two-year primary mission.

A manned mission to Mars and back would take two to three years, based on the scenarios currently studied by NASA. The space agency's exploration roadmap calls for astronauts to journey to Mars and its moons starting in the 2030s.

"Our observations are already being used in planning for human missions," Hassler, a researcher from the Southwest Research Institute in Boulder, Colo., told journalists.

Solar storms recorded
Most of the exposure recorded by RAD came in the form of five spikes in solar radiation levels during the cruise phase, including a monster spike in March. To determine how much protection the MSL spacecraft's outer shell provided, Hassler and his colleagues compared the internal readings from RAD with levels in the space environment that were recorded by a satellite known as the Advanced Composition Explorer. The researchers found that the highest peaks of solar activity were reduced by two orders of magnitude, or roughly a factor of 100.

"The lesson here is that these events happen very quickly, and they can be very intense, but with proper shielding we can help prepare for future human missions to Mars," Hassler said.

Experts are looking into potential ways to beef up the radiation shielding for deep-space journeys — for example, by distributing water and other supplies in a particular way around the outside of the capsule, or by creating a more heavily shielded "safe haven" for use during solar storms. In addition to solar storms, galactic cosmic rays contribute to radiation exposure levels in space.

After the landing, RAD will be able to compare the space exposure levels to the exposure levels on Mars itself. The Martian surface is thought to be pummeled by radiation to a far greater degree than Earth, primarily due to the fact that the Red Planet has a much thinner atmosphere and no global magnetic shield to divert electrically charged particles. Hassler said the RAD experiment could lead to much better models to predict the effects of space radiation on future deep-space astronauts.

More about Curiosity and space radiation:

• What will we see from Mars, and when will we see it?
• Even ordinary microbes may survive Martian radiation
• How a long mission to Mars could kill you
• Is there a virtual Mars in our future?

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA

Sources tell NBC News that NASA will provide further support for the development of the Boeing Co.'s CST-100 capsule (left), Sierra Nevada Corp.'s Dream Chaser space plane (middle) and SpaceX's Dragon capsule (right).

Update for 12:55 p.m. ET Aug. 3: Boeing, SpaceX and Sierra Nevada are due to receive up to $1.1 billion to continue work on spaceships that could be carrying astronauts to orbit in the 2015-2017 time frame. Check out today's updated story.

My earlier report from Aug. 2: Teams headed by the Boeing Co., SpaceX and Sierra Nevada Corp. will be receiving hundreds of millions of dollars from NASA over the next 21 months for further development of spaceships capable of transporting astronauts to and from the International Space Station, knowledgeable sources told NBC News today.

NASA is to make the official announcement of the winning commercial teams on Friday morning — but NBC News' Cape Canaveral correspondent, Jay Barbree, received word from two sources who were informed of the decision in advance, on condition of anonymity. The sources did not discuss how much money any of the companies would be receiving.

The coming phase of the spaceship development effort — known as Commercial Crew Integrated Capability, or CCiCap — is aimed at producing the design for an entire launch system, including the "space taxi" capsule and launch vehicle as well as ground and recovery operations. The three companies tapped for future funding already have received hundreds of millions of dollars from NASA during earlier development phases. Boeing has gotten $131 million for work on its proposed CST-100 capsule, Sierra Nevada has been allotted more than $125 million for its Dream Chaser space plane, and SpaceX has won $75 million to upgrade its Dragon space capsule to carry crew.

SpaceX, known more formally as Space Exploration Technologies, has also received almost $400 million from a separate NASA program to support the development of the Dragon and Falcon 9 rocket for cargo deliveries to the space station. The successful flight of a Dragon to the station and back in May opened up the way for SpaceX to start regular cargo deliveries under a $1.6 billion contract with NASA.

Representatives of SpaceX and Sierra Nevada had no comment on the news. NASA said it would not announce the agreements until Friday morning, as scheduled. Efforts to contact Boeing were unsuccessful so far tonight. The Wall Street Journal, meanwhile, quoted industry sources as saying that Boeing and SpaceX were expected to share the bulk of NASA's CCiCap money, and that Sierra Nevada seemed likely to emerge with a smaller award.

NASA invited companies to submit proposals in the range of $300 million to $500 million for development of their spaceship designs through May 2014, with potential optional milestones as well. Under an agreement with congressional leaders, the space agency will provide the full negotiated amount for two companies, plus half of the requested funds for a third company. It's an arrangement I like to call "Two and a Half Spacemen," playing off the title of the popular CBS sitcom.

What about the also-rans?
Other companies sought unsuccessfully to win CCiCap funding — most prominently, a consortium that included ATK, Lockheed Martin and Astrium. The consortium's Liberty launch system would adapt the ATK-manufactured solid rocket booster that was used for the space shuttle and the now-canceled Ares 1 rocket. The second stage would be based on Astrium's Ariane rocket. The composite capsule would be provided by Lockheed Martin, which is the prime contractor for NASA's more capable Orion deep-space capsule.

Other contenders from previous rounds of development included Blue Origin, which was founded by Amazon.com billionaire Jeff Bezos; and Excalibur Almaz, which is adapting Russian technology for its launch system.

NASA officials have said they'd be willing to continue advising the also-rans on an unfunded basis. On the other side of the table, all of the companies involved in the CCiCap competition have said they intended to continue spaceship development efforts even if they didn't win NASA's financial support, but at a reduced pace.

What lies ahead?
Boeing, SpaceX and Sierra Nevada have said their spaceships could be ready for NASA's use in the 2015-2016 time frame if they received adequate funding from the space agency. Last month, Ed Mango, NASA's manager for the Commercial Crew Program, told me that the middle of the decade seemed doable, but suggested that 2015 might be too soon.

"By the end of the base period, you need to have an integrated design that you have talked with the government about," Mango said. Actually launching a demonstration spaceflight with a crew might serve as an optional milestone, he added.

Boeing and Sierra Nevada are partnering with other companies to develop their launch system — and the most notable partner in both cases is United Launch Alliance, which could launch Boeing's CST-100 as well as Sierra Nevada's Dream Chaser on its Atlas 5 rockets. SpaceX, in contrast, is pursuing its effort on a solo basis.

With last year's retirement of the space shuttle fleet, NASA must depend on the Russians to transport U.S. astronauts to and from the space station, at a cost of around $60 million a seat. All of the companies involved in the Commercial Crew Program say they can do the job for less money than the Russians. In comparison, the cost of flying the space shuttle was estimated at $1 billion or more per mission.

Like the shuttle, the new space taxis are being designed to carry up to seven astronauts.

The commercial space taxis are an essential piece of the strategy worked out by the White House and NASA to free up money for the development of the Orion multipurpose crew vehicle as well as a heavy-lifting Space Launch System. The Orion and SLS would be used for exploration beyond Earth orbit, featuring trips to a near-Earth asteroid by 2025 and journeys to Mars and its moons in the 2030s.

Update for 11:15 p.m. ET: I want to emphasize that Jay's sources did not tell him which companies are getting more or less money than other companies. They only named the three companies. The Wall Street Journal's report suggests that Boeing and SpaceX will be getting more money than Sierra Nevada, but we don't have any information about that angle of the story. NASA promises that all will be revealed in the morning, and of course we'll pass that along. 

More about the spaceship competition:

• Follow the money in the commercial space race
• Handicapping the commercial space race
• Why SpaceX is setting the pace in the space race
• Cosmic Log archive on commercial space

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

AP / Mel Evans

In this file photo, Chuck Feld of West Chester, Pa., works on his sand art during a sandcastle contest in New Jersey. New research shows that just a dash of water is all that's needed to hold together the sand grains.

Just in time for the dog days of summer, scientists have revealed the winning formula for sturdy, sky-piercing sandcastles. The secret ingredient is a dash of water.

Daniel Bonn, a physicist at the University of Amsterdam in the Netherlands, and colleagues explain that water is necessary to form capillary forces that help sand grains bridge, or stick together.

While we all know that some water is necessary to turn the dry sand between our toes into suitable building material, the new research shows that just 1 percent water by volume is the perfect amount.

Less surprising, the team also found the wider the base, the higher a sandcastle can reach into the sky before buckling under its own weight.

Using the optimum mixture of water and base, sandcastles reaching 16 feet high are possible, according to the research published Thursday in Scientific Reports. 

Pakpour et al / Scientific Reports

Using commercially available hydrophobic sand, it is possible to build an underwater sandcastle.

What’s more, the team found that even taller sandcastles are possible when using water-repellant sand (yes, there is such a thing) and building the structures underwater. 

“In this case the air and not the water ‘wets’ the grains and we can simply interchange water and air, which does not change the bridge force,” the team reports. 

“This makes it possible to build underwater sandcastles, which are even more spectacular than normal ones."

In case you’re wondering why university scientists are spending their time building sandcastles, they say their research has practical importance to civil engineers dealing with soil mechanics.

John Roach is a contributing writer for NBC News Digital. To learn more about him, check out his website.

NASA

NASA's Curiosity rover has seven cameras mounted on its mast, including the two-camera, full-color Mastcam system; the four-camera, black-and-white Navcam system; and ChemCam, which monitors the effects of the rover's laser blasts. The Mars Hand Lens Imager is one of the instruments on the rover's robotic arm, the Mars Descent Imager is mounted on the robot's belly, and the eight-camera Hazcam system rounds out Curiosity's array of 17 cameras.

The 17 cameras on NASA's Curiosity rover are capable of sending back unprecedented, jaw-dropping, full-color views of Mars — but don't expect to be wowed by the first images. In fact, they just might be literally the size of postage stamps, in black and white.

Millions of people will be watching NASA's coverage of Curiosity's landing at 10:31 p.m. PT Sunday (1:31 a.m. ET Monday), on displays ranging from palm-sized smartphone screens to the giant screen in New York's Times Square. If the landing is successful, the first thing we'll see is bunches of grown men and women acting like giddy teenagers, pointing at blips on their computer monitors. What we definitely won't see are the 2-megapixel, color images that Curiosity's best cameras are capable of capturing.

Instead, we might see 64-by-64-pixel, black-and-white thumbnails from the rover's hazard avoidance cameras, or Hazcams. If NASA's Mars Odyssey orbiter has time to relay more data from Curiosity, they might be 256 pixels square. Or there might be no pictures at all, just because Odyssey wasn't able to acquire enough of a signal fast enough.

In that case, we'll have to wait for Odyssey's second orbital pass, at around 12:45 a.m. PT Sunday (3:45 a.m. ET Monday). The fisheye-view Hazcam images sent during that opportunity could be 512 pixels square or maybe even 1,024 pixels square.

Why we'll have to wait
There's a simple reason why we won't be seeing the big, beautiful pictures from the cameras built into Curiosity's mast: That mast, which rises 6.5 feet (2 meters) above the Martian surface when fully extended, won't be deployed until later in the week. First, the rover's eight Hazcams (four looking forward, four looking backward) will have to do a quick check of the surroundings.

A couple of gems could become available later Monday. For instance, there might be a picture from NASA's Mars Reconnaissance Orbiter, showing Curiosity and the rest of the $2.5 billion Mars Science Laboratory payload descending through the Red Planet's atmosphere. MRO was able to snap a picture of the Phoenix Mars Lander's descent in 2008, and if the orbiter captures a similar view this time around, that could be released around 9 a.m. PT (noon ET) Monday.

The first thumbnails from Curiosity's Mars Descent Imager could be released around 4 p.m. PT (7 p.m. ET) Monday. That camera, also known as MARDI, should have recorded a sequence of color frames looking down from the rover during its descent, and once they're all relayed back to Earth and put together, they'll make for a great movie.

By Wednesday, the rover could be sticking out its robotic arm to let the Mars Hand Lens Imager, or MAHLI, take a full-color picture of the ground surrounding Curiosity. The mast should be raised around this time as well. First, the navigation camera system, or Navcam, is due to send back some nice, quick black-and-white views. By Thursday, the full-color Mastcam system is expected to be sending back wide-angle and fixed-zoom images.

Star of the show
Mastcam promises to be the star of the show once the mission hits full stride: The system's right-eye camera has a telephoto lens, capable of reading the "ONE CENT" lettering on a penny on the ground beside the rover, or distinguishing between a basketball and a football at a distance of seven football fields (roughly 700 yards or meters). It's called "Mastcam 100" because of the camera lens' 100mm focal length.

The left-eye camera (Mastcam 34) has a wide-angle, 34mm lens that captures a scene three times wider. It can snap 15 images in about 25 minutes to create a full-color, 360-degree panorama. Both cameras can record high-definition video at 5 frames per second, and the pictures can be combined for 3-D views.

Damian Dovarganes / AP

The seven cameras on Curiosity's mast include ChemCam, visible as a large lens at top right; the wide-angle and telephoto Mastcam cameras, visible as two rectangular eyes below ChemCam; and the four-camera Navcam system, visible as smaller round lenses to the left and right of the Mastcam pair.

NASA / JPL-Caltech / MSSS

These pictures show what the wide-angle and telephoto cameras of the Mastcam system could see at a distance of 10 meters (33 feet). The top image (Mastcam 34 equivalent) covers an area about 14 feet (4.3 meters) across and has a resolution of one-third of an inch (0.84 centimeter). The bottom image (Mastcam 100 equivalent) covers an area 61 inches (1.55 meters) across and has a resolution of one-eleventh of an inch (less than a quarter of a centimeter).

The panoramic cameras on NASA's Spirit and Opportunity rovers had to take multiple images using different filters to create color pictures, but the imaging chip used in each of Curiosity's Mastcam cameras is built to produce full-color views with one snap. "It's identical to what most consumer cameras have," said Justin Maki of NASA's Jet Propulsion Laboratory, who's a co-investigator on the Mastcam team and the lead engineer for the Hazcam and Navcam systems.

The Navcam system has four cameras, which are set up to produce left-eye and right-eye views in black and white. (Each "eye" is doubled up for redundancy's sake.) The Curiosity team will rely on the Navcam views to plot the rover's course during the two-year mission. It takes just 10 minutes for Navcam to produce a 360-degree panorama.

"Rover missions are highly dependent on the images," Maki explained. "The entire mission is occurring within the images we receive. ... When we land, we actually start with that first panorama. We bootstrap ourselves starting with that first images, and then we drive into those images and do it again."

Rover can take self-portraits
The MAHLI ("Molly") camera serves as the equivalent of the hand lens typically used by geologists to take a close look at rocks. It's similar to but more capable than the Microscopic Imager used on Spirit and Opportunity. At closest range (about 0.8 inch, or 21 millimeters), MAHLI can achieve a resolution of 14 microns (less than a thousandth of an inch). Its images will be in full color, which is a step above the Microscopic Imager's black-and-white views. MAHLI can use LED lighting to illuminate its target. And it can be focused at different ranges to produce microscopic detail in depth.

Because MAHLI is mounted on Curiosity's robotic arm, which can be extended to a distance of 6.2 feet (1.9 meters) from the front of the rover's body, that camera can be raised to see over an obstacle that blocks Mastcam's view. It can also be turned around to take a nifty self-portrait of the rover.

The black-and-white ChemCam camera, situated at the top of Curiosity's mast, can be used to study soil and rocks from a distance, but it also serves a specialized purpose: to observe the sparks given off by the rover's rock-zapping laser. The light from those zaps will also be analyzed by three spectrometers inside the rover to determine a rock's chemical composition.

Curiosity may be more loaded up with imaging technology than the geekiest camera-toting tourist, but it's good to keep a sense of perspective here. This mission is not just about the technology. The point is get the best view available of terrain that rises more than 3 miles (5 kilometers) above the floor of Gale Crater, potentially recording billions of years of geological change. That's something that will make Curiosity's vistas unlike any seen before.

"The biggest difference is that we're landing next to a mountain, so the images are going to be spectacular even if they're in black and white," Maki told me. "The most exciting thing is where we're going."

More about Mars:

• Curiosity aims to unlock Martian mysteries
• Mars team takes '7 Minutes of Terror' in stride
• 'Star Trek' icons marvel over Mars
• Is there a virtual Mars in our future?

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

NASA / GSFC

An artist's concept shows how a crew aboard an orbiting station could control robotic operations on Mars, ranging from real-time rover trips to rocket launches bringing shipments to the station.

Imagine a day when virtual reality gets so good that you could take a computer-generated walk on the Martian surface, right here on Earth. Or imagine having a space station in Martian orbit that can control robots down on the Red Planet in real time, just as today's drone pilots control winged robots that are flying half a world away.

Science fiction? Today, yes. But someday, it could be science fact. At least that's the way Caltech astronomer George Djorgovski and other virtual-world researchers see it.

"I certainly think that virtual presence will play a significant role in space missions in the future, just because it’s so much easier to send a robot than to keep people alive" in the space environment, he told me. "That is something we can speculate about."

Djorgovski and I will be speculating about this and other prospects for immersive virtual reality tonight on "Virtually Speaking Science," a talk show that takes place in the Second Life virtual world as well as on the Web via BlogTalkRadio. The hourlong show gets started at 9 p.m. ET (6 p.m. PT / SLT). If you miss hearing it live, never fear: The podcast will be archived on BlogTalkRadio's website as well as on iTunes.

Virtual-reality exploration
NASA's one-ton Curiosity rover, which is due to be lowered down to Mars' Gale Crater late Sunday night (Pacific time), could bring the vision of virtual-reality exploration one step closer, said Rich Terrile, director of the Center for Evolutionary Computation and Automated Design at NASA's Jet Propulsion Laboratory. 

"We can actually create immersive data sets with the Mars exploration rovers," he told me. "We're certainly going to try to do that with a limited number of data sets from Curiosity as well. ... People are on board to take what Curiosity does, and try to create the best we can in terms of immersive data sets, to demonstrate their value and power. And maybe as the mission goes on, we'll have opportunities to create richer and richer data sets."

Ultimately, those data sets could give scientists — and even the general public — the opportunity to put on VR helmets or 3-D goggles in a specially laid-out room, and walk through what appears to be a realistic Mars landscape. Scientists could conceivably interact with the environment and take measurements as if they were geologists on Mars.

"It turns out that you gain a tremendous amount with just a very few frames if you’re just interested in the science of understanding Mars," Terrile said. "On the opposite end of that, If you are someone in the public and you want to look at a landscape, then the value of that really increases slowly until you almost have a complete data set. ... Somewhere in the middle, we have to weigh the value."

Terrile said increasingly sophisticated computer modeling can fill in the gaps in data sets, turning millions of observations from different vantage points into a smooth virtual experience. You still need lots and lots of data. "That’s what we struggle with, particularly in a Mars mission, where our time is limited and the amount of data we can send back to Earth is limited," he said. "But I think we're clearly getting to the point where we can create a lot more of these immersive data sets."

Telepresence in Martian orbit
The way Terrile sees it, it's only a matter of time before the power of computing and communications brings a virtual Mars within reach — and brings us closer to the real Mars as well. During a NASA-sponsored meeting on future Mars concepts, held last month, Terrile argued that immersive telepresence could offer a "new paradigm" for Mars exploration. Instead of using data from robots on Mars to create a virtual environment, future explorers could set up VR-ready space stations in Martian orbit to control those robots in real time. That's not possible now, due to the delays involved in sending signals between Earth and Mars.

"When we run a rover from Earth, if we want it to stop or turn around, it’s 14 minutes from the time we push the brake to the time when the thing actually brakes on Mars," Terrile said. "Now, take the human, and instead of operating the vehicle from Earth, you could be operating the vehicle from Mars orbit. It’d be a lot safer environment for the human [than the Martian surface], and a lot less expensive than having to deliver a human to the surface with all the resources that a human would take, and then getting that human off the surface again."

Eventually, humans would probably want to have their own feet on Martian ground, but robots could clear the way with less risk. "Wouldn't it be nice to land and have your shelter built and your  power station built and all your resources built?" Terrile asked. "You can do all that with machines from Mars orbit."

NASA

A human wearing a virtual-reality helmet and other control devices operates a NASA Robonaut mounted on a wheeled rover chassis during a test at Johnson Space Center. Learn more about Robonaut telepresence.

Will all this technology be available by the 2030s, when NASA expects to be ready to send astronauts toward Mars and its moons? Terrile doesn't lay out a timeline, but he thinks it could happen surprisingly quickly. 

"I work a lot outside JPL, in the areas of virtual reality and augmented reality, and the field is just exploding," Terrile said. "In terms of what technologies are available, we gain a factor of two about every 13 months, in terms of Moore's Law and computational resources, and we get that for free. Somebody else is creating that technology for us, and that benefits the human race. I'm hoping to get NASA interested in utilizing thse technologies, because people are going to start seeing them in entertainment. We're going to start seeing them in games. We're going to see them in tourism and museums. So I'm hoping to look for those first opportunities to use them within NASA. I think they’re going to be incredibly powerful."

Immersive data in the lab
Long before that VR lab enters Martian orbit, immersive virtual reality could become routine in earthly labs. That's the vision that Djorgovski has been trying to turn into reality through the Meta Institute for Computational Astrophysics, or MICA. We'll be doing tonight's "Virtually Speaking Science" talk in front of a live virtual audience at MICA's small auditorium in Second Life.

"A lot of our action in Second Life and OpenSim so far has been trying to understand how to effectively visualize the highly complex data sets that scientists generate," Djorgovski said. "And what immersive virtual reality buys us, in addition to what a good graphical program will do on the desktop, is that scientists can interact with themselves, with the data, in virtual space. Their colleagues can 'walk' into their data. And then there is a subjective quality issue that all users of virtual space know: Somehow there is a high-fidelity illusion of reality and presence. That is what we’re trying to harness as a scientific tool."

Courtesy of George Djorgovski

Second Life residents Desdemona Enfield and Curious George work on a virtual-reality visualization that classifies stars, galaxies and quasars according to their colors, brightness, distance and morphology.

Djorgovski specializes in the huge data sets that are associated with all-sky astronomical surveys, looking for clues to the nature of black holes, quasars and other little-understood phenomena. There could be hundreds of parameters to be measured for hundreds of millions of objects. Visualizing that abstract data through immersive virtual reality just might offer the best way for scientists to wrap their heads around huge research challenges.

Progress has come more slowly than Djorgovski expected, due to several factors.

"One is that the technology just wasn't ready," he explained. "The technology's getting much better very quickly — driven by movies and games. There's money to be made, and that's why we're getting better and better 3-D representations. Another thing is, I think, just the inertia of adopting new things. That is what holds back most of the academic community. They consider immersive virtual reality to be like a game, for obvious reasons. There is a stigma associated with it. That’s not something serious. Of course you can use that technology merely for games, or you can try to use it for serious science and scholarship, which is what we’ve been trying to do. Gradually, this will be a normal way in which we can interact with cyberspace behind our computer screens, or whatever replaces those."

Djorgovski is in the process of phasing out MICA now that funding for the experimental program has run out. But he's ramping up a different project known as Virtual Caltech, which could well represent the next small step toward that virtual giant leap. "We're still at the stage of the beginning of the S curve as far as the adoption of technology is concerned. But sooner or later I think this will be a normal thing. Everybody will be interacting with other people or with information through some sort of 3-D interface."

How much sooner or later? "I really couldn't tell," he said. "I thought that by now we would all be using avatars, and so on, but it's probably going to take a few more years."

The way Djorgovski sees it, the human body is built to interact with a three-dimensional world. For millennia, we've been missing a dimension when it comes to interacting with information.

"Right now we're used to dealing with two-dimensional representations of data, knowledge and information, which is just historical heritage," he said. "Paper or writing surfaces were historically how we started representing information. If we had three-dimensional paper, we would have used it. Now the technology is finally enabling us to represent information in three-dimensional spaces. The exact hardware implementation is going to be who knows what, but it's going to be something that will naturally click with human perception."

Will the vision of immersive virtual reality stand up to a reality check? Join us tonight for "Virtually Speaking Science," and be sure to come with questions for Djorgovski. If you're listening to the show over BlogTalkRadio, you can tweet your questions, using the hashtag #AskVS.

Tune in "Virtually Speaking Science" on BlogTalkRadio or in Second Life. George Djorgovski and I will be at the StellaNova Small Auditorium, courtesy of the Meta Institute for Computational Astrophysics, at 9 p.m. ET (6 p.m. PT/SLT) tonight. If you miss the live event, don't worry: It'll be archived by "Virtually Speaking" on BlogTalkRadio as well as iTunes.

Previous episodes of "Virtually Speaking Science":

• JPL's Dave Beaty previews Curiosity's mission on Mars
• SETI Institute's Seth Shostak about aliens and UFOs
• Paul Doherty on solar eclipses and the transit of Venus
• Veronica Ann Zabala-Aliberto on spaceflight and Yuri's Night
• JPL's Dave Beaty on the search for life on Mars
• Shawn Lawrence Otto on science and politics
• Ig Nobel impresario Marc Abrahams on silly science
• Rocket scientist Robert Zubrin on Mars exploration
• Propulsion expert Marc Millis on interstellar spaceflight
• Sean Carroll on the puzzling frontiers of physics
• Rand Simberg on the private-enterprise vision for spaceflight
• Martin Hoffert on the future of energy policy
• George Djorgovski on science in virtual worlds
• Alan Stern on suborbital research and NASA's mission to Pluto
• Col. 'Coyote' Smith on the outlook for space solar power
• Tim Pickens on rocket ventures and the Google Lunar X Prize

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

When it comes to Trek vs. Trek, it's usually Kirk versus Picard — but a brand-new pair of NASA videos previewing the Mars Curiosity rover's landing offers a different study in constrasts. Kirk versus ... Wesley Crusher?

NASA is following up on the $2.5 billion Mars mission's wildly successful "Seven Minutes of Terror" movie trailer with two versions of a video titled "Grand Entrance": one voiced by William Shatner, who played Captain James T. Kirk with classic swagger on the original "Star Trek" series; and the other by Wil Wheaton, who played kid genius Wesley Crusher on "Star Trek: Next Generation" and went on to become a geek icon (for example, as Sheldon Cooper's nemesis on "The Big Bang Theory").

The script for both four-minute-plus Mars videos is pretty much the same: They both begin with shots of Curiosity's assembly and move quickly through the Mars Science Laboratory mission's launch last November. They both spend a lot of time on the rover's entry, descent and landing, which is set for 10:31 p.m. PT Sunday night (1:31 a.m. ET Monday). They both marvel at the unprecedented sky-crane operation that will lower Curiosity to the surface from a rocket-powered platform.

Both Shatner and Wheaton end up addressing the main aims of the rover's two-year primary mission: How habitable was Mars in ancient times? What chemical clues remain detectable today? "This nuclear-powered, 1-ton rover will take us ever closer to examining deep layers of history, and perhaps closer to an answer to the ancient question: Was there ever life on Mars?" they say.

NASA says there's room for both videos.

"Shatner and Wheaton are mavericks in inspiring film, TV and social media audiences about space," Bert Ulrich, NASA's multimedia liaison for film and TV collaborations, said in a news release. "NASA is thrilled to have them explain a difficult landing sequence in accessible terms that can be understood by many. Thanks to their generous support, Mars exploration will reach Tweeters, Trekkies and beyond!"  

But the dueling videos cry out for a totally unscientific popularity poll: How do you prefer your "Grand Entrance"? A la Kirk, or with a dash of Wesley? Or do you think "Seven Minutes of Terror" beats them both? Feel free to cast your vote in the poll above, and weigh in with your comments below.

More about the Mars mission:

• NASA rover closing in on Mars
• Experts bet on Martian sky crane
• How Curiosity will look for Martian water
• What success or failure on Mars would mean

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.

Sending balloons into the stratosphere for final-frontier views is a feat that's now within reach of thousands of do-it-yourselfers, but the flight conducted on Monday by a team of high-school students and mentors participating in the University of New Hampshire's Project SMART was something completely different.

After the balloon's launch from Brattleboro, Vt., the cameras mounted on the scientific platform recorded pastoral panoramas of the New England countryside. Meanwhile, a miniature Geiger counter monitored radiation levels, and other instruments kept track of temperature and pressure. The scientific aim of the summer-session experiment was to see how the flux of cosmic rays varies with altitude.

By the time the balloon reached the 105,900-foot level, almost two hours after launch, the cameras were catching amazing views of the curving Earth beneath the blackness of outer space. That height is less than a third of the way to the internationally recognized boundary of space, at 100 kilometers or 62 miles, but the sight is nevertheless impressive.

Then the balloon popped. And that's when things got really interesting.

First of all, it's unusual to get such a clear video frame of the balloon actually popping. But more importantly, this mission tested a novel method for the recovery of payloads from that high up. Usually, recovery relies on a parachute landing. This time, the payload's descent was slowed by a 3-foot-wide (meter-wide), aerodynamically shaped disk made out of pink plastic foam and cardboard. No parachute was attached.

Over the course of 30 minutes, the four-pound re-entry package drifted downward to a spot 40 miles southeast of the launch point, in rural Massachusetts. When the students located the payload, it was intact.

"The re-entry vehicle was just sitting there as if someone had gently placed it on the ground,” Andrew Mahn, a senior at Sant Bani School in Sanbornton, N.H., said in a UNH news release.

UNH

A frame from the video captured during Project SMART's balloon flight shows the high-altitude balloon in mid-pop.

The successful landing proved the validity of the vehicle's plastic-and-cardboard disk design, said Louis Broad, a physics teacher at Timberlane Regional High School in Plaistow, N.H. "This represents a paradigm shift for the whole small ballooning community. I've never seen anybody else use anything but parachutes,” Broad said.

Broad and another physics teacher, Scott Goelzer of Coe-Brown Northwood Academy, were the students' guides during the four-week space science module for the Project SMART summer program at UNH. The balloon's rise and fall provided a fitting climax for the summer — and gave the students valuable experience for the future.

"It’s a simulated satellite project, from design through construction, launch, flight and recovery," Goelzer said. Building and launching the experiment cost reportedly less than $1,000. That super-low price tag suggests that the Project SMART made a super-smart investment.

Where in the Cosmos
The picture of the popping balloon served as this week's "Where in the Cosmos" puzzle on the Cosmic Log Facebook page. Three of the Facebook followers — Gabrielle Wolf-Stahl, James Sloan and Kit Watson — took no time at all to identify the picture correctly. To reward their quick wits and fast fingers, I'm sending them pairs of 3-D glasses in the mail. Want to get in on the fun? Click the "like" button for the Facebook page and stay tuned for the next"Where in the Cosmos" challenge on Aug. 11.

More high-altitude high jinks:

• Watch Star Trek action figures take flight 
• Gemini capsule launched on a string
• Teens send toy above the clouds
• Twin-balloon airship hits high frontier
• Students reach high for launch photos
• MIT acceptance letter goes to near-space

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.

Sue Mainka / IUCN

The cheetah can run more than twice as fast as the fastest human for short distances.

The Olympics is a time to celebrate the world's fastest and strongest humans, but you can rely on the International Union for the Conservation of Nature to put the best of human performance in perspective. They've just come out with their list of Olympians for the natural world — champions that range from the fleet cheetah to the humble fungus.

"While celebrating the achievements of talented athletes across the world this summer, we should also take the time to appreciate these incredible species," the IUCN says in today's Olympian roundup. Here are some of the conservation group's medalists for 2012:

Sprint: Cheetahs (Acinonyx jubatus) can bolt at 70 mph or more for short bursts, making them the world's fastest land animals. In comparison, Jamaican sprinter Usain Bolt is credited as the fastest human, with a top running speed of 27.79 mph. Theoretically, humans could reach velocities of 40 mph — still short of the cheetah's personal best. 

High jump: To even things out, cross-species-wise, the IUCN is measuring jumping ability in terms of body length. By that measure, a lowly insect known as the common froghopper (Philaenus spumarius) gets the high-jump crown. It can jump 115 times its body length, while the record for humans is just a little over 8 feet (2.45 meters). That's about 1.25 times the height of the record-holder, Cuba's Javier Sotomayor (6-foot-5 or 195 centimeters).

Joelle Dufour / IUCN

The rhinoceros beetle can lift 30 times its own weight.

Weightlifting: The IUCN's winner here is the rhinoceros beetle (Megasoma elephas), which can lift more than 30 times its body mass. In comparison, the IUCN notes that the heaviest individual weight lifted by a human in an Olympic competition was 580.9 pounds (263.5 kilograms), a record set by Iran's Hossein Rezazadeh. His weight as of 2007 is listed as 340 pounds (152 kilograms), which means the poor guy couldn't even lift a mass twice his own weight.

Archery: The smallscale archerfish (Toxotes microlepis) can shoot down land-based insects (flying insects or insects on branches) and other small animals with water shot from their specialized mouths.

Boxing: The mating season for the European hare (Lepus europaeus) peaks in the spring, during a time called “March Madness.” Females choose their partners according to their strength by "boxing" with them — when females and males stand on their hind legs and hit each other with their paws. As females are slightly larger than males, only the strong males impress the females and get the chance to mate. Survival of the fittest: the true gold medal. 

Gymnastics: In the animal world, it's hard to beat the agile gibbon (Hylobates agilis). 

Shooting: The fruits of the Himalayan balsam (Impatiens glandulifera) open explosively with a popping sound, "shooting" their seeds to distances of 23 feet (7 meters) or so. A prolific seed producer, each plant produces about 2,500 seeds, and its dispersal technique helps the plant colonize new areas. Native to the Himalayas, but naturalized in Europe and elsewhere, it tends to become an invasive species and outcompete other plants.

Shot put: The Lammergeier (Gypaetus barbatus), also known as a bearded vulture, is one of the largest of the Old World vultures. This bird wins the IUCN's medal for shot put because it drops large bones from great heights in order to shatter them and eat the marrow inside.

Opening ceremonies: If there's any guest you'd want to have on hand for the Olympics' opening ceremonies, it'd be Zeus olympius. That's a species of fungus that makes its home on Mount Olympus, the mythical home of the Greek gods (including Zeus, the star of the show). It's found growing on the dead branches of pine trees. The IUCN notes that Zeus olympius has recently been found in one other location on Earth: an area of southwest Bulgaria, near the Greek border.

David Minter

The fungus known as Zeus olympius has been found only on dead branches of pine trees on Greece's Mount Olympus - and recently at a spot in Bulgaria.

More of the natural world's medal winners:

• London penguins show off their Olympic diving form
• Owl competes in 100 cm sprint at London zoo
• Barracudas' tricks adapted for Olympic swimmers
• Who would win the caveman Olympics?

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.

Anyone who's looked at the "Seven Minutes of Terror" trailer for next month's Mars landing might have wondered whether the planners behind NASA's $2.5 billion Mars Science Laboratory mission really knew what they were doing — and although the planners insist they're confident, they also say they're nervous.

"There's not a whole lot we can do about it at this point, except just be nervous," said Dave Beaty, chief scientist for the Mars Exploration Directorate at NASA's Jet Propulsion Laboratory.

You can test the mood for yourself by tuning in our "Virtually Speaking Science" talk show at 9 p.m. ET tonight, via BlogTalkRadio or the Second Life virtual world. Beaty and I will be talking about the buildup to the Aug. 5 landing, and taking your questions through Second Life, Twitter (use the hashtag #askvs) and the phone lines. If you can't make it, don't worry: You'll be able to listen to the hourlong podcast via BlogTalkRadio's archive or iTunes.

Falling into place
All the pieces are falling into place for the Mars Science Laboratory's landing sequence, aimed at putting the subcompact car-sized Curiosity rover down within Gale Crater. On Tuesday, NASA maneuvered its Mars Odyssey orbiter into the correct trajectory to pass over the landing site just in time to pick up telemetry from the probe.

The MSL spacecraft is currently within 2.2 million miles (3.6 million kilometers) of Mars and closing in fast. The big nail-biter is scheduled for just after 10 p.m. PT on Aug. 5 (1 a.m. ET Aug. 6), when the spacecraft is supposed to blaze through Mars' atmosphere, spring a parachute, pop off its heat shield and let loose a rocket-powered sky crane platform that will hover about 66 feet (20 meters) above the Martian surface and lower Curiosity on cables. Then the cables will cut loose and the sky crane will fly itself out of the way, leaving Curiosity to get down to business.

JPL

Dave Beaty is chief scientist for the Mars Exploration Directorate at NASA's Jet Propulsion Laboratory.

What were they thinking???

"I've met with the engineers," Beaty told me. "I've seen their presentations, and they can be very convincing. But you have to hold your breath a little bit and trust that they know what they're doing."

This multibillion-dollar mission depends on everything working right — and there's even more at stake than just the mission. If next month's landing fails, that could spark even more questions about the future of NASA's troubled Mars exploration effort. The failures of Mars Climate Orbiter and Mars Polar Lander in 1999 led to years of rethinking and retrenchment, and the soul-searching would probably go far deeper in this current age of tightened budgets and downscaled ambitions.

On the other hand, a successful landing would set a sunny tone for what's likely to be years of exploration by the most capable interplanetary robot ever created. During tonight's talk show, Beaty will probably be a lot more willing to talk about that type of scenario, just as he was when I interviewed him on Monday. Check out this edited transcript, and bring your follow-up questions to "Virtually Speaking Science" at 9 p.m. ET.

Cosmic Log: So, there's less than two weeks before the big Mars landing — what's going on there at JPL?

Dave Beaty: We're getting very nervous. There's not a whole lot we can do about it at this point, except just be nervous. But this is a significant thing. It's one of these points in history that may change the trajectory of things that happen afterward, whether we end up with a successful landing or an unsuccessful landing.

Q: What do you see as the outcome for failure, and the outcome for failure? What would that mean to the Mars exploration program?

A: Well, just having a successful landing, by itself, is of course huge good news. It enables the scientific return from the mission to happen, which will play out over the next Mars year — that's two Earth years, more or less. Once the rover lands, it has to raise its antenna, do some checkouts, get moving, and then drive over to this mountain that has the stratigraphy we're interested in.

It's sort of like the Grand Canyon way of looking at rock. You get this beautiful exposure of stratigraphy because of the erosion of this mountain. We want to climb up the side of the mountain and check the layering, like John Wesley Powell did just after the Civil War when he went one-arming up and down the Grand Canyon. That was one of the great geological expeditions of all time, as far as I'm concerned.

The site we want to look at is great. It's a little hard to predict exactly what we're going to see inside those rocks if we end up on the success pathway. We know what we're looking for: What are the rocks? What is the nature of the layering? Are there signals that the layers were "habitable" — i.e., had the potential for a life form to have lived there, had a life form been present. If there's a positive outcome on that, then we would definitely want to send another mission — either back to the same place, to check out whether there's any sign of something actually there; or potentially to another place that has the same kind of layering, but some other kind of characteristic.

Here on Earth, one of the big issues we face is that the preservation of the signs of life is very uneven. We know that there's life everywhere on Earth, right? And it's been here in sort of the form that we see it when we look out our windows, back to the time of the Cambrian, which is 600 million years ago. But if you look at the sedimentary rocks, they don't all contain fossils, they don't all contain pollen. You've got to look carefully to understand what has happened to the rock since its formation, and whether it would have included the signs of life, and whether those signs would have survived through all the subsequent things that happened to the rock.

It's not a guarantee that we would go back to exactly the same place, but we would certainly want to go back somewhere if we received this encouragement.

Q: And the implications of failure?

A: If it's a bad landing, the question would be, what is the reason why? In my experience, the public and Congress and all the people surrounding us would be accepting of a failure that was just a bad weather day, or if you land sideways on a rock, or some other sort of bad luck that happens because of what Mars has done to us. They tend to be less forgiving of a mistake made by a human being here on Earth. So, those are two very different kinds of scenarios. Just the fact of a bad day doesn't tell you enough to know what the implication might be. 

Q: A lot of people wonder about how the sky crane is going to work, or whether the heat shield will work properly — the "seven minutes of terror." Is that what you have in mind? Everything that could be done has been done, of course, but if something goes wrong, I suspect people will want to focus on the process for doing something that's never been done before.

A: Almost everything we do at Mars has never been done before. That's what makes this exciting from the point of view of the engineers. They're here to do the impossible. That sky crane landing has some very powerful advantages, if it works. I've met with the engineers, I've seen their presentations, and they can be very convincing. But you have to hold your breath a little bit and trust that they know what they're doing.

Q: If everything works nominally, will we see the sky crane become the main method for getting large payloads down to the surface of Mars?

A: I absolutely think so. For the robotic exploration missions, the bigger question is, do we want the payloads to keep getting bigger? We know for sure that the pathway to eventual human missions has to involve bigger and bigger payloads, because the humans and all their support systems are heavy. This particular landing system will land a payload that's bigger than can be landed with airbags. The airbag would not survive. So it is heading in the direction that we need to follow if we believe in eventual human exploration. Whether the next robotic mission needs to be the same size as MSL — that's an interesting question. We may want to get it smaller, in part to bring the cost down.

Q: What's your role going to be on the night of the landing?

A: I just got my assignment. I will be at Beckman Auditorium at Caltech, with an audience of 1,136 people, which is the auditorium's capacity. I'll be standing in front of them with the NASA feed on the screen behind me, and my instructions are to narrate it like a tennis match. You can interject a little bit of commentary, but you don't want to detract from the main show, which is what's on the screen.

Q: So when will you know if the landing's been successful?

A: The landing itself is at 10:32 p.m. Pacific time, and we've placed both orbiters [Mars Odyssey and Mars Reconnaissance Orbiter] so they will be in position to watch the descent as it comes down. By 10:32 or 10:33, they should have the data to know whether the landing was successful. They may get an ambiguous answer and not know for sure whether it was successful or not successful. That may take a little while longer to sort that out. It's hard to end up with a for-sure crash scenario quickly, because the signals are likely to be less than obvious. But if it's successful, we'll know very quickly.

Tune in "Virtually Speaking Science" on BlogTalkRadio or in Second Life. Dave Beaty and I will be at the StellaNova Small Auditorium, courtesy of the Meta Institute for Computational Astrophysics, at 9 p.m. ET (6 p.m. PT/SLT) tonight. If you miss the live event, don't worry: It'll be archived by "Virtually Speaking" on BlogTalkRadio as well as iTunes.

Previous episodes of "Virtually Speaking Science":

• SETI Institute's Seth Shostak about aliens and UFOs
• Paul Doherty on solar eclipses and the transit of Venus
• Veronica Ann Zabala-Aliberto on spaceflight and Yuri's Night
• JPL's Dave Beaty on the search for life on Mars
• Shawn Lawrence Otto on science and politics
• Ig Nobel impresario Marc Abrahams on silly science
• Rocket scientist Robert Zubrin on Mars exploration
• Propulsion expert Marc Millis on interstellar spaceflight
• Sean Carroll on the puzzling frontiers of physics
• Rand Simberg on the private-enterprise vision for spaceflight
• Martin Hoffert on the future of energy policy
• George Djorgovski on science in virtual worlds
• Alan Stern on suborbital research and NASA's mission to Pluto
• Col. 'Coyote' Smith on the outlook for space solar power
• Tim Pickens on rocket ventures and the Google Lunar X Prize

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

American Library Association

Former astronaut Sally Ride, left, and her partner, Tam O'Shaughnessy, discuss the role of women in science and how the earth's climate is changing during a 2008 American Library Association conference in Anaheim, Calif. Ride and O'Shaughnessy collaborated on several children's books on science.

In life, Sally Ride became famous as America's first woman in space — and in death, she's now added to her fame as the first acknowledged gay astronaut.

The revelation came in a low-key way: Monday's obituary from Sally Ride Science, the educational venture she founded a decade ago, referred to Tam O'Shaughnessy as "her partner of 27 years." A spokeswoman for Sally Ride Science, Terry McEntee, said Ride and O'Shaughnessy, who is the company's chief operating officer and executive vice president, worked out the phrasing of the announcement before Ride's death.

In an email today, Sally Ride's sister, Bear Ride, explained why the former astronaut kept quiet about her sexual orientation.

"In her inherent Norwegian reticence — in this and so many aspects of her personal life (wrestling with pancreatic cancer, for example) — she just didn't talk much (see Norwegian comment, and add to that the typical tight-lipped scientist thing)," Bear wrote. "If you read interviews from years and years back, you'll see that there was always a major frustration that she didn't comment much on 'how it feels to be the first American woman in space' — she just didn't think that way. She wanted to get the job done. Her personal feelings were just that: personal. Not right or wrong — simply Sally. Everyone who knows her well really got that about her."

Bear, a gay Presbyterian minister, takes a different approach.

"I'm a rather out-there advocate for LGBT [lesbian-gay-bisexual-transgender] rights — my partner and I have even been arrested a couple of times in public protest!" she told me. "But that's me, and not Sally."

Here's the essay that Bear Ride has been sending around as a tribute to her sister:

"Sally Ride was the first American woman to go into space and she was my big sister. Sally died peacefully on July 23rd after a courageous 17-month battle with pancreatic cancer.  I was at her side. We grew up in Encino, CA. Our parents, Joyce and Dale Ride, encouraged us to study hard, to do our best and to be anything we wanted to be.  In 1983 Newsweek quoted our father as saying, 'We might have encouraged, but mostly we just let them explore.' Our parents encouraged us to be curious, to keep our minds and hearts open and to respect all persons as children of God. Our parents taught us to explore, and we did. Sally studied science and I went to seminary. She became an astronaut and I was ordained as a Presbyterian minister.

"Sally lived her life to the fullest with boundless energy, curiosity, intelligence, passion, joy, and love. Her integrity was absolute; her spirit was immeasurable; her approach to life was fearless. Sally died the same way she lived: without fear.  Sally's signature statement was 'Reach for the Stars.' Surely she did this, and she blazed a trail for all the rest of us.

"My sister was a very private person. Sally had a very fundamental sense of privacy, it was just her nature, because we're Norwegians, through and through. People did not know she had pancreatic cancer, this is bound to be a huge shock. For 17 months, nobody knew, and everyone does now. Her memorial fund is going to be in support of pancreatic cancer.

"Most people did not know that Sally had a wonderfully loving relationship with Tam O'Shaughnessy for 27 years.  Sally never hid her relationship with Tam. They were partners, business partners in Sally Ride Science, they wrote books together, and Sally's very close friends, of course, knew of their love for each other.  We consider Tam a member of our family.

"I hope the pancreatic cancer community is going to be absolutely thrilled that there's now this advocate that they didn't know about.  And, I hope the GLBT community feels the same. I hope it makes it easier for kids growing up gay that they know that another one of their heroes was like them."

Sex has always been a tricky topic for astronauts: In the old days, they worried that if they didn't conform with the "Right Stuff" stereotype, they wouldn't be picked for spaceflights. Issues such as alcohol abuse or marital problems often were swept under the carpet. Is it any surprise, then, that no active or former astronauts have publicly announced that they're gay? Michael Cassutt, the author of "Who's Who in Space," is quoted on Space.com as saying that such an announcement would be a "career-wrecker."

Men and women have been working together on U.S. spacecraft since Ride's history-making flight in 1983. Why not straights and gays? Maybe Sally Ride's low-key way of coming out will represent one small step toward greater acceptance and acknowledgment of the LGBT contribution to the space effort. (I'm using the term "gay" here as admittedly inadequate shorthand for the LGBT community. The fact that Ride was married to fellow astronaut Steven Hawley from 1982 to 1987 complicates any effort to categorize Ride's perspective, based on the public record. And Buzzfeed's Chris Geidner quotes Bear Ride as saying "Sally didn't use labels.")

Slideshow: Astronaut Sally Ride

- / AFP/Getty Images

See images from the life and career of astronaut Sally Ride, the first American woman to fly in space.

Launch slideshow

Ride's legacy lives on
Ride would no doubt be uncomfortable with a public discussion of her sexuality. She was uncomfortable enough with the celebrity that surrounded her as the first American woman in space. Based on the comments from her family and co-workers, Ride's main concern in the last days of her life was making sure that Sally Ride Science survived her passing.

"I was very fortunate to spend time with her right before she passed away," said Karen Flammer, a research physicist at the University of California at San Diego and one of the founders of Sally Ride Science. "We were able to talk about what she envisioned for our company, and our legacy and her legacy."

Ride's status as a former astronaut wasn't uppermost in her mind, Flammer told me. "Her true passion really was science education, and inspiring more young people, particularly girls, to follow a career path in science and technology," she said.

Since Ride's death, Sally Ride Science's donors have confirmed that they "want to continue funding and supporting our programs," Flammer said. "The transition will be hard, but we want to keep going as a tribute to her."

Those programs include science camps as well as global outreach efforts such as EarthKAM, which lets middle-school students request pictures of Earth to be taken by a digital camera aboard the International Space Station. "We've engaged hundreds of thousands of middle-school students, not only in this country, but around the world," Flammer said.

A similar program, called MoonKAM, lets kids select targets for pictures taken by NASA's GRAIL lunar probes.

Flammer said there will be a new chief executive officer for the company: a woman who has had experience running other educational companies and "who is going to share all of our passions." However, Flammer said it's still too early to announce the CEO's name.

And speaking of names, Flammer and her colleagues are looking into somehow putting Sally Ride's name in space. "Right now, we're in the process of working with NASA on what types of things we can do in her honor. ... Her tribute statement always was 'Reach for the Stars.' That's how she ended the talks she gave to students, or to adults. So we're keeping that in mind with whatever we come up with."

But the most valuable tribute to her memory will be Sally Ride Science.

"She never wanted the celebrity status," Flammer told me. "What she really wanted was for her legacy to continue. This is what she wants to survive her and live on: her name, and her science education company."

In memoriam
Sally Ride Science's Terry McEntee said the memorial service would be private, but if you want to pay tribute to America's first woman astronaut, here's what the company's website suggests:

"In lieu of flowers, you may wish to make a gift in memory of Sally to the Sally Ride Pancreatic Cancer Initiative (Fund 4191). Checks should be made out to: UCSD Foundation. Also, in either the memo line or in an enclosed note, please state that the gift is made in memory of Sally Ride or to the Sally Ride Pancreatic Cancer Initiative (Fund 4191).

"Gift mailing address: Pam Werner, Executive Director of Development, UCSD Health Sciences Dev., 9500 Gilman Dr. #0853, La Jolla, CA 92093-0853."

"If you prefer using a credit card, please call Pam Werner at 858-246-1556. Please note that 94 percent of donations will go toward pancreatic cancer research at UCSD Moore's Cancer Center."

More about Sally Ride:

• First US woman in Space, Sally Ride, dies at 61
• Tributes stream in: 'Ride, Sally, Ride'
• Why pancreatic cancer is so deadly

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.