Add two more stripes to this ingenious chart showing all the attempts over the past 50 years to send spacecraft to Mars. Let’s hope that the stripe for the Curiosity Mars Science Laboratory, which launched successfully on Saturday, reaches all the way to the surface of the planet.

Sadly, the stripe for Russia’s Phobos-Grunt Mars spacecraft, currently incommunicado in Earth orbit, appears doomed to end at the outside, “fail” ring, which may also spell the end of the country’s planetary program.

The apparent demise of Phobos-Grunt got me reading up on the history of Russian Mars exploration, looking for stories from happier days.  I hadn’t known about PrOP-M, the first rover (or maybe crawler is a better word) launched to Mars. It ended up failing , too, but it would have been fun to watch had it succeeded.

By 1971 the Soviets had already landed one Lunokhod rover on the moon’s surface. The 10-pound PROP-M, included as a payload on the Mars 3 lander launched in May 1971, was much more modest.  After Mars 3 touched down, the rover, attached to a 15-meter umbilical cord, was designed to shuffle away from the lander on two ski-like contraptions. The video below (queued up here at the 3:51 mark) shows how the rover maneuvered itself.  Unfortunately, Mars 3 went silent immediately after it touched down, and PROP-M was never heard from again. NASA didn’t land its own rover on Mars until 1997, when Sojourner rolled off of the Mars Pathfinder.

When Curiosity touches down on Mars next August, it should tip its electronic head in the direction of PROP-M, wherever it lies on the unforgiving plains of Mars.

Apollo 11

Where were you on July 20, 1969, when Apollo 11 astronauts Neil Armstrong and Buzz Aldrin first walked on the moon? What were you doing on October 4, 1957 when the Soviets launched Sputnik? Do you remember April 12, 1981, when the space shuttle Columbia made its first flight?

In 2008, the Smithsonian’s Folklife Festival included the program “NASA: Fifty Years and Beyond,” and as part of that program, visitors were encouraged to document (written on note cards and recorded on tape) their memories of America’s space program.  A few of the festival-goer’s memories appear below.

As the 50^th anniversary year of human spaceflight draws to a close, we ask you to remember your own space milestones. After you read the remembrances here, leave a comment to tell us where you were, what you saw, and how you felt.

I had just learned to drive my husband’s stick shift car. He worked in the simulation lab with astronauts. I was stopped in front of their building to pick up my husband. As he got into the car, he said, “There’s Neil.” I said, “Neil who?” He said, “Armstrong! Who else?” At that point I went limp, the clutch jumped, the car lurched forward, and Neil just missed being hit.

I grew up in Huntsville, Alabama. I remember Werner von Braun was our most famous citizen. Huntsville was very sleepy until Sputnik was launched. All of a sudden, Huntsville became a hotbed of activity, all centered on the space program. Within three years, the U.S. had an active space program. Many of the engines for spacecraft were built in Huntsville. Huntsville calls itself “The Space Capital of the Universe” now. In 1950, it was known as “the Watercress Capital of the U.S.” Things change!

In 1957 Sputnik went up and the talk was that U.S. students had to catch up academically. I was 10 years old—the next day was the first time we ever had homework in school.

I was in second grade when the entire student body of Norfeld Elementary reported to the auditorium to watch a not-very-big portable black-and-white TV for a Mercury capsule splashdown in the Atlantic. We were all worried that it could miss and veer back into space forever. (It went OK.)

When I was in elementary school, a man came to the school and sang songs about Black Holes. Needless to say, I was terrified.

I’ve been fascinated by space exploration for my entire life. My family tells me that my first word was “moon.” Now I work as a NASA contractor, on a mission to the Moon (LRO). I’m grateful to be standing on the shoulders of giants, the men and women before and beside me that helped NASA and all space agencies achieve what they have. And we’re only at the beginning of the adventure.

Phobos as viewed (in false color) by NASA's HiRISE camera in 2008.

Mars has not been a happy place for the Russian space program. The nation’s attempts to explore the Red Planet, going back more than 50 years, have produced a long litany of failures. The most recent misfire came 15 years ago, when the instrument-laden Mars 96 probe, instead of heading out into the solar system, burned up in the atmosphere and scattered pieces over Chile and Bolivia.

That crash effectively put the Russian planetary program out of business — until now.

On Tuesday a Zenit rocket is scheduled to lift off from Kazakhstan to start the Phobos-Grunt spacecraft on its 10-month voyage to Mars. If all goes well, on Valentine’s Day of 2013, after several months of circling the planet, the lander will touch down on the surface of the moon Phobos to start collecting samples of dirt (“grunt” in Russian). Four days later, a return vehicle will lift off in the moon’s low gravity and bring the samples back to Earth.

We’ll have more details on the Phobos-Grunt mission next week. Meanwhile, here’s some background from Anatoly Zak, the author of our 2008 article, and an animation (with Russian subtitles) from the Roscosmos space agency that shows how it’s all supposed to go.

Cue the Lawrence of Arabia theme. Actually, I prefer the soundtrack that the Mars Exploration Rover team used for this time-lapse video showing Opportunity’s 13-mile trek from Victoria crater to Endeavour crater. They took accelerometer data from the rover and converted it to audible sound, which gets louder when the robot is moving over rocky ground, and quieter when it’s crossing sand dunes. The trip to Endeavour took three years, compressed here to three minutes. Here’s a view from Opportunity‘s navigation camera, taken just last Monday.

What draws me to Titan is the mystery. After 50 years of robotic exploration most other objects in the solar system have given up their secrets, at least to a first order. But Saturn’s largest moon is hidden by a perpetual cloud cover, so we have to work harder to see what’s underneath.

Which is why I find maps like this so appealing. A research team led by the University of Nantes in France stitched together six years’ worth of infrared images taken by the Cassini spacecraft over the course of 70 Titan flybys to produce a global mosaic. Because infrared penetrates the clouds, the surface is revealed. In this false-color composite, highlands appear bright and equatorial dune fields appear dark.

The mosaic varies in resolution, depending on how close Cassini was to the surface at the time a particular image was taken. But some of the fuzzy areas will get sharper. Another 48 Titan flybys are planned between now and 2017.

Among the things one expects to find while sifting through former President Bill Clinton’s stuff, a lost moon rock might be low on the list.  The half ounce piece, one of the Goodwill Moon Rocks brought back on Apollo 17, was given to Arkansas three decades ago and reported missing sometime last year. Wednesday morning, reports the AP, an archivist who was looking through the former governor’s papers opened a box and discovered it. No one knows how it got in there, but the archivist, Bobby Roberts, who directs the Central Arkansas Library System, seems content to set ‘em up and knock ‘em down, “I guess it’s one more Arkansas mystery solved.”

Apollo 11 moon rocks. Photo credit: NASA

This recently found moon rock is one of about 200 small fragments presented as gifts to foreign nations, U.S. states and territories. All were sliced from a single Apollo 17 sample, number 70017, and many are unaccounted for today. Various investigations have been pursued over the years to track down these and other missing moon rocks, including Operation Lunar Eclipse, the joint sting operation between NASA, the U.S. Postal Service and U.S. Customs that recovered the Goodwill Moon Rock originally given to Honduras.  Another somewhat famous escapade includes the interns at Johnson Space Center who smuggled out a 600 pound safe containing samples from all the Apollo missions (the F.B.I. caught them).

NASA’s Office of the Inspector General keeps tabs on any information surfacing about moon rocks, both to collect missing pieces and to sweep counterfeit rocks off the market. Updates are published in the office’s semi-annual reports — just last year they recovered a Goodwill Moon Rock intended as a gift to Cyprus (pdf), however, “The plaque had been intended for delivery by a U.S. diplomat to the people of Cyprus as a gift when hostilities broke out in that country. The plaque had remained in the custody of the diplomat until his death and was recovered from his son.”

Wikipedia’s moon rocks page collects more stories, such as the ill-fated gift to Ireland: the Apollo 11 rock ended up in a landfill. (Their Apollo 17 rock is safe in a museum, at least.) Clearly, some of these will never be recovered.  But sometimes, every once in a while, you can just open a box.

Over the years, spacecraft have seen plenty of dried-up riverbeds on Mars, along with rocks that formed in watery environments eons ago. No question about it, the Red Planet used to be wet. NASA can stop sending press announcements about water in the Martian past. We got it.

Now scientists are reporting something much more exciting: the first strong evidence of liquid water currently on Mars.

Pictures taken by the HiRISE camera on the Mars Reconnaissance Orbiter show dark streaks at the foot of steep slopes, which scientists say are probably the traces of salt water that reaches the surface. We’re not taking about rushing streams. In their paper in Science magazine reporting the findings, Alfred McEwen of the University of Arizona and his co-authors write: “We assume [the streaks] are usually dry at the surface, perhaps wet only in the subsurface and perhaps in small surface areas while moving.” So maybe it’s like damp beach sand after a wave has just retreated. The streaks, which range from 2 to 15 feet in width, appear by the hundreds in seven different places (20 more locations are under investigation) during the Martian summertime, when temperatures can reach as high as 80° F. The seasonal flows, if that’s what they are, have been traced in the HiRISE images for as long as three Martian years.

HiRISE pictures of Newton Crater, spanning more than a year, show dark streaks interpreted as being traces of flowing salt water. (Image: NASA/JPL-Caltech/U of Arizona)

As often happens, the scientists can’t be 100 percent sure. McEwen says the best way to nail down the case for liquid water is through laboratory studies on Earth. Part of the problem is that water on Mars doesn’t behave like water on Earth, and is unlikely to last very long on the surface due to the planet’s cold temperatures and the weak atmospheric pressure. That makes it difficult to observe from afar unless you happen to be looking at just the right time.

Best of all would be to visit those locations with a lander. Unfortunately, the Curiosity rover planned for launch to Mars in November—the most sophisticated lander ever sent to the planet—won’t go anywhere near the newly found streaks. And even if it could, NASA wouldn’t send it there. Watery environments may be the best places to look for signs of life, but Mars scientists face an ethical Catch-22: By the rules of “planetary protection,” you can’t send an unsterilized rover to a place where it might contaminate native Martian life. And sterilizing a rover like Curiosity is time-consuming and expensive.

It’s a dilemma.

How do you pack a $2.5 billion Mars rover for shipment? Here’s how.

This time-lapse video, covering a period of five days, shows the Curiosity Mars Science Laboratory being prepared for shipment from NASA’s Jet Propulsion Laboratory to its launch site in Cape Canaveral, Florida. The journey, scheduled for later this month, will be partly by truck, and partly by Air Force aircraft.

Last night NASA made one last attempt to contact the Spirit Mars rover, which got stuck in the sand two years ago and hadn’t been heard from since March 22. Nobody expected a response after 1200 previous unanswered messages, and sure enough, there was no answer from Mars. So, with the chances of success “practically zero,” according to project manager John Callas, Spirit has officially been pronounced dead.

Nobody can say it didn’t have a good run. The rover lasted for more than six years on Mars, when the requirement was just three months. Callas told reporters yesterday that when Mars scientists meet later this summer to review Spirit‘s scientific results, the mood will be more like an Irish wake than a funeral. Besides, its twin rover, Opportunity, is still going strong.

Here’s a recap of Spirit‘s life on Mars from some of the people at NASA’s Jet Propulsion Laboratory who knew the rover best.

Virgil Tracy (foreground) flanked by bro Gordon (orange sash), and engineer "Brains" (who designs the team's equipment).

Who can forget billionaire ex-spaceman Jeff Tracy and his five sons (Scott, Virgil, Alan, Gordon, and John), each named after a Mercury astronaut? Remember how they—through their organization (International Rescue)—um…rescued people…internationally? Ok, so they were puppets. Deal with it, people!

The Royal Air Force Museum (London) invites fans of the 1960s television show Thunderbirds to revisit their inner child (as well as the museum) on May 14 and “play with giant sized versions of classic children’s games whilst listening to music of the 60s and 70s.” The museum will also have on display original models, and will air episodes from Thunderbirds and Captain Scarlet in the museum’s cinema. Sylvia Anderson, the voice of Lady Penelope and the co-creator of the show, will discuss her career, the actors she worked with, and the inspiration behind the puppets. (Anderson and her husband are the creative team also responsible for Space: 1999, starring the wooden Barbara Bain and the over-the-top Martin Landau.)

Screenshot of Thunderbird 2 copyright Carlton International Media Limited.

Our marionette heroes use a variety of air- and spacecraft to carry out their missions. Thunderbird 2 (usually piloted by son Virgil Tracy, he of the intimidating eyebrows, above), is a large green VTOL aircraft used in most of the team’s earth-based rescue missions. The big bird can fly anywhere in the world without refueling, and cruises along at 2,000 mph, but can achieve 5,000 mph when needed. Amazingly, it is not the team’s fastest mode of transport. That honor goes to Thunderbird 1 (typically piloted by Scott Tracy), a hypersonic rocket that can travel 15,000 mph, or Mach 22.6. You’d think that a rocket capable of that speed would have extremely complex controls, but no. Thunderbird 1 is controlled by a mere two control levers. Life is so easy when you’re a puppet!

Screenshot of Thunderbird 1 copyright Carlton International Media Limited.

By Ismael Roman, third place, category 3 (14 to 17 year olds).

Each year, the National Aeronautic Association (NAA) and the National Association of State Aviation Officials (NASAO) organize an art contest meant to encourage young people to become familiar with (and participate in) aeronautics, engineering, and science.

“The quality of the art we see is unbelievable,” says Dik Daso, who has been a judge for the past five years. Daso, a curator of modern military aircraft at the Smithsonian National Air and Space Museum, along with two other judges, selected nine first-, second-, and third-place winners from approximately 170 state finalists.

The theme of this year’s contest was the 50th anniversary of human spaceflight, and more than 6,800 students from 24 states participated in the U.S. competition. (Students first compete at the state level; each state aviation organization then sends its finalists to NASAO.)  The artwork of the U.S. winners (who range in age from 6 to 17 years old) will be entered in the international aviation art contest, held in Lausanne, Switzerland this month.

For those states that do not hold a competition, students and teachers were able—for the first time—to send submissions to Embry-Riddle Aeronautical University’s Prescott, Arizona campus, which then grouped submissions by state. “What’s interesting,” says Kathryn Solee, president of the NASAO Center for Aviation Research and Education, “is that New Jersey sent over 400 pieces of art to Embry-Riddle, and had two national winners.”

By Nolan Riggin, first place, category 1 (6 to 9 year olds).

“100 years ago, your great-great-grandparents read about traveling through space in science fiction books,” reads the contest brochure. “50 years ago, your grandparents listened [to] the radio or watched on television when the first human orbited the earth, and today you can watch a small crew of astronauts from around the world share living and research quarters on the International Space Station on your laptop computer….  Time to grab your favorite paintbrush or markers, buckle up into a secure position in front of your desk, and blast off into your imagination…”

By Brian Sun, second place, category 2 (10 to 13 years old).

Through a process of elimination, each judge argues for his or her favorite pieces. Since the winning artwork will be made into posters, “you look for themes that have public appeal,” says Daso, “in addition to artistic skill.”

Daso’s interest in the competition goes beyond enjoying the artwork, however. “I’m very excited to see young people getting involved, really involved with aviation topics,” says Daso.

By Karen Ahn, first place, category 2 (10 to 13 year olds).

Image from usedblooksblog.com.

“Those who have never seen a living Martian can scarcely imagine the strange horror of its appearance…. Even at this first encounter, this first glimpse, I was overcome with disgust and dread.” —H.G. Wells, War of the Worlds, 1898.

Wells wasn’t alone in thinking Red Planet Dwellers would be a complete fright to behold. Charles Warner wrote in an 1896 edition of Harper’s that, “[Martians] may be in the shape of a single wheel, able to roll easily anywhere, or in that of a sphere, or of a cigar…. The Martian lord of creation may have wings, he may be a gigantic insect, or a noble sort of eagle….. He may, indeed, have four dimensions instead of three, and instead of five senses a dozen, and among them common-sense.” Yeah, baby, Yeah!

For a wonderful online exhibition of "War of the Worlds" book covers, visit drzeus.best.vwh.net/wotw

The American astronomer Garrett Serviss wrote about Martian superiority circa 1905: “The Martian intelligences might look upon us as we look upon monkeys in a menagerie, and their learned doctors might say: ‘See what we were like once!… Give them time, and place them amid our surroundings, and who knows but that they might develop electro-magnetic vision, electro-magnetic hearing and electro-magnetic muscular control? They might even discover the secret of using inter-atomic energy, which has saved us.’ ”

An anonymous article appeared in an 1886 issue of the British magazine Chamber’s, speculating that Martians “would be about fourteen feet high on the average…. We should, therefore, expect to find that the Martialites have executed large engineering works; perhaps also their telescopes are much superior to ours, and we have been objects of interest for their observers.”

The examples above were gathered by K. Maria D. Lane, a geography professor at the University of New Mexico, for her new book Geographies of Mars: Seeing and Knowing the Red Planet (University of Chicago Press, January 2011). Lane argues that at the turn of the 20th century, the moment in which the public became obsessed with the inhabitants of Mars, European imperialism and American expansionism “produced an intellectual and social climate in which the view of Mars as an arid, dying, irrigated world peopled by unfathomably advanced beings was really the only interpretation of Mars observations that could plausibly been accepted by large numbers of Western scientists, writers, and audiences.”

For a Mars timeline stretching from 1700 to 1959, visit The Planetary Society’s page, which includes a blurb about the 1910 Thomas Edison-produced four-minute film, A Trip to Mars: “A famous professor discovers that when he mixes two magical powders, he has the power to reverse gravity. As he tests the concoction, some of the powder falls on him, and he is lifted up and flies through the sky until he finally falls on the surface of Mars. He escapes some gnarly-limbed trees only to fall over a ridge and land on the lip of a giant Martian.”

New planetary candidates range from Earth-size to Neptune-size to Jupiter-size. (Image: NASA/Wendy Stenzel)

When a veteran planet hunter like Debra Fischer calls it the most momentous discovery since 51 Peg, you know it must be big.

In 1995, scientists found the first planet circling a normal star outside our solar system—an unassuming yellow dwarf called 51 Pegasi. In the 16 years since, they’ve identified more than 500 such exoplanets.

Today they tripled the total in one announcement.

Actually, the Kepler spacecraft science team is only claiming 1,253 new candidate planets, based on four months of staring at 155,000 stars in the constellation Cygnus. Most still need verification with ground-based telescopes, and perhaps 20 percent of the claims will wash out, according to Fischer, who was on the panel presenting the Kepler findings to the press today.

Still, the number is impressive. According to Kepler project scientist William Borucki, his telescope is only surveying 1/400th of the sky. So by extrapolation, half a million new planets might be out there, easily detectable with a Kepler-style telescope, which watches for dips in light as a dark planet crosses in front of a bright star.

Kepler’s new batch of 1,253 candidates includes 68 Earth-size- planets,  288 “super-Earths” (twice as big as our own world), 662 the size of Neptune, and 165 the size of Jupiter. The telescope even found one sun-like star called Kepler-11 with six planets, a record.

A whopping 54 of the new candidates orbit in the so-called habitable zone of their star, where temperatures would theoretically be moderate enough for life to exist. And five of those 54 are Earth-size.

Finding a true Earth analog—a planet the size of our own, circling a star similar to the sun at roughly the same distance—requires three years of data. That’s how long it will take to get repeated crossings of the sun’s disk for orbits the size of Earth’s.

So, says Borucki, we’ll need patience to find a close match of our own planet around another star. But that doesn’t mean some of the 54 planets announced today, or even their moons, couldn’t harbor life of some kind.

Meanwhile, you can join in analyzing the Kepler data at the “Planet Hunters” site. So far, says Fischer, some 16,000 people around the world have participated in this nifty example of “citizen science.” They’ve already turned up hundreds of candidates, most of which are likely to overlap the list released today by the professionals.

Artist's conception by L. Calçada/ESO

Having already found more than 500 planets circling distant stars, scientists are getting better at understanding what they’re made of. A group led by Jacob Bean at the Harvard-Smithsonian Center for Astrophysics reports in this week’s Nature that they’ve analyzed the atmosphere of a planet only slightly larger than our own for the first time. And they may have found water —or rather, steam.

The planet, called GJ 1214b, has a radius about 2.6 times larger than Earth’s, and orbits a star located 40 light-years away in the direction of the constellation Ophiuchus. Scientists knew from previous observations that the planet must have an atmosphere, because its density is too low for an all-rocky planet. Theoretical models suggest three possibilities: A) a cloud-free hydrogen atmosphere, B) high clouds or haze obscuring a deeper hydrogen atmosphere, and C) an atmosphere made mostly of water vapor.

Bean and his colleagues used the 3.6-meter Very Large Telescope in Chile to analyze the spectrum of starlight filtering through the planet’s atmosphere. The data led them to rule out option A and favor option C, the steam world (although B is still a possibility). And future infrared observations should be able to distinguish between B and C.

Sadly, though, “the planet would not harbor any liquid water due to the high temperatures present throughout its atmosphere,” say the authors.

Photo: Huang Jingwen / Xinhua

What impresses me most about the new photos of the moon taken by the Chinese Chang’e-2 orbiter is not their beauty (although they are pretty) nor their sharpness (NASA’s Lunar Reconnaissance Orbiter returns higher resolution images). It’s the fact that they were unveiled by Premier Wen Jiabao (left).

I can’t think of an occasion where a U.S. head of state showed that much interest in a purely scientific (unmanned) space mission. The closest thing I could find after a quick search is this 1965 shot of Lyndon Johnson being shown photos from the Mariner 4 Mars probe, two weeks after the flyby.

More Chang’e-2 photos are at this Chinese-language page at the China National Space Administration. Here’s a nice one: