Space Probes: The Inner Planets | Free Documentary Space

[00:00:04]Are you a sensation seeking planetary traveler?

[00:00:08]Well, here are some challenging nearby spots you can't pass up. There is a runy pockm marked Mercury, sunblasted, continually bombarded, and atmosphere freom with a thousand degree difference between night and day.

[00:00:26]Then there's our evil twin, Venus. Here, you can be instantly cooked and crushed at the same time.

[00:00:35]Both are devilishly hard to study.

[00:00:40]Or perhaps the mysterious red planet is your cup of tea. Thanks to our roving friends, we're learning that [music] Mars is more Earthlike than we ever predicted.

[00:00:50]And it may only be a matter of time before they're joined by human explorers beyond Mars. These fearless spacecrafts are showing us that even the seemingly cold, [music] lifeless asteroid belt is more dynamic than scientists could imagine.

[00:01:07]These are the stories of a lonely blue marble sending its intrepid little machines to places no human can yet go to the far ends of the solar system and beyond.

[00:01:27]There are two rocks closer to the sun than Earth, and they've been doing their best to [music] confound scientists since we first pointed telescopes at the sky.

[00:01:38]Little Mercury especially [music] orbits so close to the sun. Just pointing a telescope at it is a very bad idea.

[00:01:48]And only two craft, both unsung heroes really, have ever made it there.

[00:01:56]Waiting for launch on November 2nd, 1973.

[00:02:00]Sitting at top a powerful Atlas Centaur rocket, Little Mariner 10 presented a real nailbiter.

[00:02:08]Among a host of firsts, it would be the first craft to use gravity assist.

[00:02:14]Gravity assist is what happens when a spacecraft flies by a planet and the planet grabs the spacecraft and tosses it on because the planet itself has motion around the sun. So on a [music] mission to get to Mercury, it will use Venus to toss it in toward the sun.

[00:02:33]Things went haywire almost from the start. The heaters that would warm the craft's television cameras didn't work and wouldn't reboot.

[00:02:45]The spacecraft went through so many glitches that one scientist would come up with a very unscientific description.

[00:02:52]It seemed neurotic.

[00:02:56]>> All the systems we send have personalities and sense they have quirks and you have to learn how to help them deal with their quirks.

[00:03:02]>> Engineering knowledge is such a moving target for their era. It was extraordinarily complicated.

[00:03:10]The control team managed to outenineer the bulky probe and on March 29th, 1974, it reached the innermost planet coming within a breathtaking 450 m from its surface.

[00:03:27]For the first time, humanity got brilliant images of this mysterious [music] planet.

[00:03:34]At first glance, it looked an awful lot like our pockmarked [music] moon, but there were features not seen on any other planet.

[00:03:45]Written on its pitted face was the violent history of how our solar system formed, including our Earth.

[00:03:58]As the inner planets grew, they were bombarded with and absorbed more and more space lumps and clumps.

[00:04:11]The record of the bombardments have long eroded away on Earth, but little Mercury being so close to the gravitational pole of the sun is still a shooting gallery.

[00:04:25]By 1975, the probe was running out of gas. But the Earthlings controlling it managed [music] to ek out not one but two more flybys of the planet, providing beautiful pictures of the South Pole.

[00:04:40]>> And it mapped about 40% of the surface and uh eventually we ran out of fuel and for Mercury that was a real feat.

[00:04:54]Scientists bid a bittersweet farewell to the probe, turning off its transmitters, and all was silence.

[00:05:08]To this day, unless it's been hit by some space trash and fallen into the sun, it continues to orbit our star, slowly baking away in the terrible radiation.

[00:05:25]It would be 36 years before we went back to Mercury.

[00:05:29]Now the mission would be trickier to actually orbit the planet for the first time.

[00:05:37]So close to the sun, the tug of gravity is so great that Mercury has to zoom through space at over 100,000 mph, faster than any other planet. So getting into orbit would be quite a feat and require a very strange route to get there.

[00:06:00]The craft was dubbed Messenger.

[00:06:03]A very ambitious [music] science loaded space probe unlike anything seen before.

[00:06:10]>> Main engine start two one and zero and liftoff of Messenger on NASA's mission to Mercury. After launch in 2004, it set off on a dizzying seven-year journey.

[00:06:26]7 years. It takes just 7 [music] months to get to Mars.

[00:06:32]As you're moving in towards the sun, you're accelerating the whole way. So, you have to carry a really enormous amount of fuel to to slow down to get there.

[00:06:42]>> So, we use the gravity of Venus to slow down the spacecraft.

[00:06:48]And you can't do all of that in one shot. You got to go around and around.

[00:06:52]We went by Venus twice and Mercury three times. And then finally on the fourth time, our fuel was just enough to slow the spacecraft down enough so that we could indeed get into orbit to stay at Mercury.

[00:07:15]It was [music] March 18th, 2011 when Messenger slipped into orbit.

[00:07:24][snorts] >> It has been an amazing spacecraft. The technology challenge was great especially in building the sun shade that was operating at something like 300 plus° centigrade.

[00:07:43]The scrappy probe set about on its one-year mission, but wasn't about to [music] settle for that, though. Within 2 years, the Messenger mapped the full surface of [music] Mercury, half of which had never been seen before [music] and knocked the socks off the scientists at home.

[00:08:02]the fact that there was indeed water ice in the holes on the North Pole where the sun never reaches.

[00:08:13]>> And it's not a small amount, perhaps up to a trillion tons.

[00:08:18]How did it get there? [music] The leading theory suggests it arrived from icy comets raining down, which may actually [music] be how Earth got its oceans.

[00:08:28]And it just says that at the time of formation of the solar system, water was everywhere. And in the case of Mercury, because there are craters from the great bombardment, some of the water became ice. So once ice, it will stay ice as long as the sun doesn't look at it.

[00:08:53]In 2012, Messenger determined that Mercury is basically a bowl of iron wrapped in a cocoon of rock. The iron core is about 85% of its [music] radius, a massive fraction compared to our Earth's core, which is 50% of the planet's [music] radius.

[00:09:13]And Mercury's center is molten and moving, giving the little planet an oversized magnetic field.

[00:09:24]Finally, [music] by the spring of 2016, the can do messenger probe finally ran out of gas and NASA bid the craft [music] a fond farewell.

[00:09:35]>> We are calling it end of mission for messenger. [applause] Well, of course, when you spend this many years in designing and [music] then testing and you know, it's part of your everyday existence and all of a sudden it's no more.

[00:09:58]>> On April 16th, the probe dove into the surface of the planet at almost 9,000 mph.

[00:10:06]It took these last photos on the way down. Of course, there was a sense of sadness, but also pride and satisfaction that it enabled us to do much more science than we had any right to expect.

[00:10:34]>> So, planetary adventurer, perhaps Mercury isn't your cup of tea.

[00:10:39]Maybe you'd prefer a trip to our sister planet, Venus. Almost exactly the same size as Earth, the closest planet [music] to us. Surely, it's the one that would be most welcomingly Earthlike.

[00:10:54]Well, before the space age, we thought so. You can't see anything of Venus from Earth except atmosphere.

[00:11:02]So people envisioned a place thick with air, vast oceans, and lush greenery.

[00:11:13]It was only when we got there that we realized it was our evil twin, the opposite of our comfy home base and perhaps even a glimpse into our nightmarish future.

[00:11:28]With a runaway greenhouse effect from its thick atmosphere, the surface of Venus is hot enough to melt lead.

[00:11:38]Full of volcanoes belching toxic gases and would crush a human instantly.

[00:11:47]Much of what we know of the hell planet comes from [music] the Soviet Union.

[00:11:52]They just kept blasting probes at it through the 60s,7s, [music] and 80s, watching them fail or be instantly destroyed by Venus's insane conditions until they finally got a lander to the surface, which functioned for just minutes before failing.

[00:12:11]The Cold War race between the US and the Soviet Union extended into planetary missions. Um, most certainly there were parallel efforts by the Soviets to send [music] spacecraft to Venus and Mars.

[00:12:24]The Soviets turned out to be pretty good [music] at Venus and not so good at Mars. But they had a pretty decent success with the fourth [music] uh Venus probe Vanera 4 which descended quite a long way before into the the Venuian atmosphere before being [music] crushed and sent back data on the atmospheric density and pressure helped resolve a longstanding [music] controversy over the composition of the Venus atmosphere.

[00:12:52]Finally, on December 15th, 1970, Vanera [music] 7 became the first spacecraft to land on another planet. It confirmed the worst.

[00:13:04]At the planet's surface, the temperature was 932° F, and the atmospheric pressure was 75 [music] times that of Earth.

[00:13:16]It's so hot we'd find out later that it snows metal at the tops of Venucian mountains.

[00:13:25]And these are respectable mountains.

[00:13:28]Maxwell Montes, the tallest peak on Venus, is almost 2 m higher than [music] Mount Everest.

[00:13:36]Vanera 7, crafted of metal alloys that could withstand the pressures of deep sea diving, lasted some 50 minutes.

[00:13:45]The surface of the planet turns out to be about [music] the surface of molten lead. The pressures are worse in a sense than trying to dive into the bottom of the Earth's oceans. So what happened to the early spacecraft is they were simultaneously overheated and crushed.

[00:14:02]Undaunted, the Soviets continued to bombard the planet with probes. And in 1975, Vanera 9 took the first close-up photograph of the planet's surface.

[00:14:15]In the end, the Russians managed to send 13 craft [music] that returned information about our closest neighbor, eight of which landed and four of which returned images. Considering their descent into hell, it's almost an unbelievable accomplishment.

[00:14:35]And then there were the Soviets Vega missions with very lofty and slightly whimsical goals to deploy balloons into Venus's insane atmosphere.

[00:14:47]In 1985, twin Vega probes dropped pairs of landers and balloons at Venus.

[00:14:54]No other mission has ever deployed balloons on another planet.

[00:14:59]Unbelievably, both the 11t diameter balloons managed to drift for nearly 2 days in the Venian atmosphere, covering almost 7,500 miles, nearly the diameter of the planet.

[00:15:16]They were able [music] to survive so long because they were about 35 m above the surface.

[00:15:22]Here, the weather is comparatively balmy. Plenty of sunshine, pressures and [music] temperatures not much different than Earth's.

[00:15:30]Just great if you ignore the fact that the [music] clouds are sulfuric acid and whirl around at 200 mph.

[00:15:42]It's been some three decades since anyone landed on Venus or ballooned in its atmosphere. It's just that hard.

[00:15:50]Several orbiters have managed to map almost the entire surface of the planet like the US Mellan spacecraft, the European Space Ay's Venus Express, and most [music] recently Japan's Akatsuki Venus Climate Orbiter.

[00:16:15]But the dream of humans visiting Venus is not dead. Looking good, Havoc.

[00:16:22]>> Still, those dreams may take a backseat to our other, more inviting Earthlike neighbor.

[00:16:32]In the movie The Martian, a scientist struggles to stay alive after being abandoned on the desolation of the red planet. Of course, that's fiction. But did you know we've already sent three scientists? Two geologists [music] and a biologist to Mars. Their names are spirit, opportunity, and curiosity. And there are intrepid [music] roving investigators.

[00:17:01]This is surely the cutest family tree in the history of space travel.

[00:17:06]It's all of NASA's Mars rovers, generations of robot gumption, stretching back to 1997 when little Sojourer made her debut on the surface of the red planet.

[00:17:20]Her larger descendants, the twins, Spirit and Opportunity, blew the minds of their controllers, and Opportunity [music] is still at it.

[00:17:33]And the youngest, biggest beast is Curiosity, now starting its fifth year of groundbreaking research and exploration.

[00:17:47]Sojourer hitched a ride with the Mars Pathfinder mission.

[00:17:51][applause and cheering] After landing, Pathfinder opened its pedals and Beagle-sized Sojourer started out on a planned 7-day jaunt, exploring the Martian terrain.

[00:18:08]She spent 83 days wheeling around, snapping pictures, and chemically tasting the terrain and the atmosphere.

[00:18:16]Pathfinder really showed us how important it [music] was to have mobility on the surface of a planet so that you can see the most interesting thing. to go over and sample it. Uh if you're fixed in place, you're limited as to what you can reach. [music] So mobility is key.

[00:18:34]What Sojourer found was that Mars had volcanic rock very much like the Earth's, [music] suggesting what scientists suspected, that the red planet had gone through an evolution very much like our own planets long in the past.

[00:18:51]>> [music] >> In 2003, the same year Sojourer was inducted into the robot hall of fame, the next generation of rovers, twins, Spirit and Opportunity, blasted off [music] from the Kennedy Space Center, about a month apart, each powered by a Delta I rocket.

[00:19:22]After a seven-month trip, the first of the twins, Spirit, was hurtling toward Mars at 16,000 mph, about 10 times the speed of a bullet.

[00:19:34]The heat shield in the front of the rover vehicle got about as hot as the surface of the sun.

[00:19:43]A supersonic parachute deployed.

[00:19:45]Atmospheric entry entry.

[00:19:48]>> It was time for the Earthling controllers to strap themselves in. It was going to be a bumpy ride for an altitude of 8,000 ft.

[00:20:00]The heat shield jettisoned.

[00:20:06]The airbags blew up in less than a thousandth of a second.

[00:20:16]And then she bounced and bounced >> 28 times.

[00:20:24][music] You know, kind of unusual when you think that [music] there's this $400 million rover inside and it's bouncing around on the surface and eventually comes to a rest. But it worked very well.

[00:20:41]Finally, the airbags [music] deflated and the solar arrays opened up, charging the power- hungry little rover.

[00:20:56]And she lifted her head, the panoramic camera, and sent her first beautiful we are here postcard.

[00:21:08][applause] Then Spirit looked homeward, snapping the first ever picture of Earth taken from the surface of another planet.

[00:21:22]Her Earthlings went crazy with joy.

[00:21:28]But then disappointment.

[00:21:31]They had landed Spirit in a crater that they had hoped was once a lake. But what they found there was not a lick of evidence of water.

[00:21:41]>> And when we landed, we found nothing but volcanic material, basaltic rocks. And so Mars had [music] thrown us a curveball.

[00:21:52]>> 3 weeks later, Twin Opportunity made its own bouncing baby rover arrival on the opposite side of Mars.

[00:22:00]>> At this point in time, you should be on ground.

[00:22:04]Standby.

[00:22:08]The Mars Exploration Rovers team were hardly the only ones to get [music] attached to their robotic critters.

[00:22:14]These charismatic machines elicited enormous affection among the public, >> partly because they were outright cute.

[00:22:22]They could have been designed by Pixar.

[00:22:26][cheering] >> Well, the rovers are adorable. I mean, they're cute. They're courageous.

[00:22:31]They're exploring on our behalf. And so it's it's hard not to become enamored with them and and affectionate with them and regard them as adorable. [music] Golf cart- sized spirit and opportunity were designed [music] to be wandering geologists.

[00:22:54]Instead of picks and hammers though, they have little particle blasters that they can use to take samples and spectrometers and microscopes to examine them. Their holy grail, evidence of liquid water.

[00:23:10]Spirit was the one that was most challenged. Nothing went right for her.

[00:23:16]She landed first. She landed in these volcanic material. We were hoping to find lake red sediments.

[00:23:23]But Spirit made up in uh Spirit what she lacked in luck.

[00:23:30]In [music] December of 2007, one of her wheels broke. Her controllers resigned themselves [music] to the extra drag.

[00:23:38]We drove it mostly backwards, dragging that right front wheel, but it was like an, you know, a ball and chain. [music] But that actually turned out to be one of the biggest scientific boons of either [music] rover because it would scrape the surface material and reveal what's just underneath stuff that we normally would just drive over because it was obscured [music] to us. And that's where Spirit made its biggest discovery.

[00:24:04]>> What Spirit had found was a kind of rock called opylene silica. This can only [music] form in the presence of both water and heat.

[00:24:16]Spirit's twin didn't need a ball and chain to make fantastic discoveries.

[00:24:20][music] >> Opportunity lands right from the get-go.

[00:24:23]Discovery of water formed rocks. Right, you know, it came easy.

[00:24:29]>> Opportunity landed on a flat plane known as Meridiani [music] Plenum.

[00:24:34]Here she found little so-called blueberries that contained hematite and iron ore which is almost always [music] associated with water.

[00:24:45]It looked as though Opportunity's landing site was once the shoreline of a salty sea, but one that was too salty [music] and acidic for life as we know it.

[00:24:58]After thoroughly investigating its landing site, Eagle Crater, Opportunity traveled to Endurance Crater and again [music] found evidence of ancient water.

[00:25:11]But it too seemed too salty.

[00:25:16]Finally, at Victoria Crater, almost 4 miles from the landing site, she found her holy grail.

[00:25:26]>> Where opportunity [music] is today is we see evidence of neutral pH water, water you could drink. I mean, ancient water.

[00:25:33]We're talking 3 and 1 half to four billion years ago. So, this is very exciting because these [music] are the conditions we think are most hospitable to the origin of life, at least as we understand it.

[00:25:45]We've certainly established [music] that the habitable conditions, the physical conditions, the liquid water, the right temperatures, sources of energy, and now neutral pH water [music] all existed at that time at a time when life started on Earth.

[00:26:02]>> Both Spirit and Opportunity did more [music] than find evidence of ancient water. They photographed Earthlike clouds in the Martian sky, found the first meteorite ever [music] discovered on another planet, and proved what scientists long suspected.

[00:26:22]The place was riddled with dust devils.

[00:26:27]Dust devils that, instead of choking our roving ladies, kept [music] them going long past their sellby dates.

[00:26:37]In 2009, after five mission extensions, Little Spirit would get stuck in soft sand, but continued sending data.

[00:26:50]She stopped communicating with Earth in 2010.

[00:26:54]and was declared dead a year later.

[00:27:00]She had explored [music] and phoned home her results for more than 5 years, traveling almost 5 miles.

[00:27:09]We had [music] worked with Spirit from the beginning and now Spirit is missing.

[00:27:14]We can't help her. She's on her own and then we never hear from her again.

[00:27:19]And we tried to look [music] for over a year. We listened with the deep space network uh every day. We sent over [music] 1,400 commands to elicit a response and [music] we heard nothing.

[00:27:32]We tried and so we don't know what the last moments were like. It's very much like a loved one missing in action because you don't know whether they're dead or alive and you don't have that sense of closure.

[00:27:49]People forget or perhaps just can't believe that Opportunity, the Lucky Sister is still going strong.

[00:28:02]After more than 12 years, 27 m and 10 mission extensions.

[00:28:08]Considering she was expected to go 600 m, that's quite a scientific bonus and set the rover bar awfully high.

[00:28:18]They both outlasted [music] uh their planned lifetimes by years and one's still running. So uh his engineering um accomplishments, they're they're pretty stunning. Curiosity has to live a long time in order to to beat Opportunity.

[00:28:34]>> Curiosity, of course, is NASA's next generation rover, lovingly crafted over many years.

[00:28:43]>> All right, stand by for test.

[00:28:46]5 4 3 2 1 fire.

[00:29:01]On August 5th, 2015, Curiosity's vehicle burst into the atmosphere at 14,500 mph and like her predecessor, deployed a supersonic parachute and jettisoned the heat shield.

[00:29:21]But instead of bouncing this baby to its landing point, they cut the cables, fired up some engines, hovered, and used a sky crane maneuver to ever so gently drop the rover to the ground and cut the umbilical. Cord.

[00:30:06][cheering] [cheering] Curiosity was born ready to roll rather than being dispatched from a lander.

[00:30:27]>> Opportunity is the field geologist for Mars. [music] Curiosity is the analytic chemist for Mars.

[00:30:37]Curiosity has a more sci-fi approach to her mission than her predecessors.

[00:30:42]Instead of touching and chemically sniffing rocks, she fires her laser [music] and X-rays at them.

[00:30:51]Chem Cam on Curiosity shoots a laser at a rock that's [music] about 7 meters away and there's material that's burned off of the surface and there's light that's given off. There's a spark and [music] then Super Cam has a detector that looks at the wavelengths of that light [music] to figure out what are the elements that are present. And this is called laser induced breakdown [music] spectroscopy, but it's basically zapping rocks with a laser beam. So we have two instruments inside Curiosity [music] that do geocchemistry measurements on powdered rocks that the rover [music] collects and it's looking at the minerals that are in the powdered rocks.

[00:31:42]The rover got her bearings where she landed in Gail Crater, where it had looked from space as though there had been water once, and got down to business.

[00:31:57]Curiosity set off for a threemile high mound called Mount Sharp in the middle of the Gale Crater at her top clip of 5 cm/s, a little over a tenth of a mile per hour.

[00:32:16]Her long journey over a plateau brought her to an intimidating active dunefield.

[00:32:26]Discretion being the better part of her honor, she took a hard right to skirt the dunes before heading up Mount Sharp.

[00:32:36]Along the way, she found formations that seemed almost certainly to have been the result of groundwater.

[00:32:45]As Curiosity continues her climb of Mount Sharp, she'll encounter younger and younger layers of soil, unfolding the history of the planet [music] the way paleontologists and geologists do here on Earth.

[00:33:04]In her four years, Curiosity has returned more than 125,000 images, fired her laser [music] almost 400,000 times and driven 8 1/2 miles.

[00:33:20]She's done everything her earthlings asked of her and far more.

[00:33:26]Curiosity [music] has been exploring Gail Crater and Mount Sharp in Gail Crater to look for all of these [music] pieces that are part of the story of habitability. And Curiosity's found all of them. So now we know that there [music] are places on Mars that at one time were habitable. So we're poised to ask the next question, which is [music] really to go look for signs of ancient life on Mars. And that's what we're doing with the Mars 2020 rover.

[00:33:55]The Mars 2020 rover, the as [music] yet unnamed great granddaughter of Sojourer, will be based on the design of Curiosity, but will be much more scientifically [music] sophisticated.

[00:34:10]Hopefully, these [music] will answer the next big questions. Is there still water on Mars today? and perhaps even life.

[00:34:23]For a [music] mere $2 billion, the Mars 2020 rover will be our pioneer in realizing the ancient dream of Earthlings to live and work on the red planet, our first stepping stone to new worlds and new possibilities.

[00:34:42]One thing is clear, Mars 2020 will have some big shoes.

[00:34:46]uh wheels to fill. It will be quite the challenge to replace Sojourer, spirit, opportunity, and curiosity in the hearts of the rover teams and their adoring public.

[00:35:02]>> You know, they're very much like our human proxies on the surface of Mars and they exhibit humanlike qualities. I mean, they're beautiful, they're intrepid, they're funny, and so we ascribe to them personalities and behaviors, and that only enders them more to us. So, they're loved ones.

[00:35:21]For our fearless explorers of the inner planets, there's one final destination to traverse before reaching the gas giants of the outer solar system, the asteroid belt.

[00:35:36]Hollywood would have you believe that this stretch of space between Mars and Jupiter is a minefield of rocky bodies, an almost impenetrable zone for any spacecraft.

[00:35:48]That picture couldn't be further from the truth.

[00:35:52]While this massive donut-shaped ring is home to millions of asteroids ranging in size [music] from pebbles to protolanets, they're separated by an average distance of 600,000 m.

[00:36:07]In 2014, after a 10-year [music] voyage, issa spacecraft Rosetta located comet 67P, [music] an object just a few kilome long hurtling through the depths of the solar system.

[00:36:21]However, the rough terrain [music] challenged the most spectacular phase of the Rosetta mission, the first attempted landing on a comet [music] with a lander equipped with a laboratory.

[00:36:33]Felt was dropped at a height [music] of 22 km or twice the cruising altitude of an airliner. It fell for 7 hours with no controls, but according to a trajectory that depended on its ejection velocity and the gravity of the comet.

[00:36:50]Each command transmitted to Rosetta is received almost [music] half an hour later. Precision, however, is vital.

[00:37:02]At 5:03 p.m. at the exact time calculated, telemetry signaled that felt had touched on the surface of the comet.

[00:37:12][applause] However, a major problem disrupts the program.

[00:37:18]After the 7-hour fall, felt touched the surface of the comet, but felt's anchor harpoons failed to fire and [music] it rebounded away.

[00:37:28]The lander with a weight equivalent to an object of about 1 gram on Earth bounced twice [music] and ascended to an altitude of over a kilometer.

[00:37:41]Before knowing if Fel has come to rest or [music] catapulted into deep space, Rosetta passed to the other side of the comet. It could no longer establish [music] contact with the lander. There would be no news until the morning when Rosetta would rise above the comet's horizon.

[00:38:02]>> In the control room, after 10 years on mission, nobody knew if a world first had been achieved or if the adventure was over.

[00:38:12]In the morning, Rosetta signaled the lander was on the surface of the comet.

[00:38:17]It had survived.

[00:38:20]This I think the emotion I felt there was so deep into my heart that you can't imagine how it was.

[00:38:27]>> Trapped in the shade of a cliff, felt was unable to recharge its batteries as planned. Before [music] they would die in about 60 hours, a maximum of instruments were activated.

[00:38:39]75% of the planned scientific data were transmitted to Earth, including [music] proof that comets can carry heavy water.

[00:38:51]With 12 scientific instruments on board, Rosetta's mission has not ended.

[00:38:58]During the 2 years, ISO researchers have been gathering [music] data, comet dust, and images. And surprisingly, the comet seemed to be changing right before their very eyes.

[00:39:11]And he said, "There's a crater that disappeared." And then we were looking at it, looking at it, looking at it. And then Hoger said, "Wait, there's another crater that just appeared." So, um it was live like like live um when we were um seeing the image, somebody detected a change. [music] And you really have to have to flip between images and you really have to look very careful because some of them are very very subtle.

[00:39:32]>> Not all of the changes were subtle.

[00:39:34]Outbursts [music] of dust and gas caused the movement of enormous boulders across the surface. In this case, by around 15 m.

[00:39:44]And a recent scientific paper revealed a dramatic cliff collapse exposing a shiny white material of most likely ice.

[00:39:55]Then while analyzing the data from the camera's final descent on board the Rosetta spacecraft was an unexpected surprise.

[00:40:04]So Midas is like a time machine for me because we can look [music] how the smallest particles in the very beginning of our solar system um have elomerated so to start to build larger particles.

[00:40:20]>> Comets can be seen as a window into our past a time capsule from the origins the beginning of our solar system. So by studying comets we get this view of what the conditions at that time were like.

[00:40:34]>> We will be able to to get very close to the nucleus and make measurement that was not uh that were not possible before.

[00:40:44]>> But the scientific instruments on board Rosetta have captured some primitive dust for scientists to examine.

[00:40:52]>> Among other things [music] they identify some glycine.

[00:40:56]We discovered that this uh carbon was actually a very complex material, very complex carbon. Because the comet is kept in a very cold environment, we [music] don't expect it to have very high temperature phases. So it can be that this material was formed closer to the sun and was then brought to the comet later. And this for us was a surprise because we knew it for the minerals but not so much for the organics. So it seems that the organics also can be transported over over large distances in the solar system.

[00:41:30]>> Then in early [music] September, the team spots Fel.

[00:41:34]The lander is on its side in the shadow of an overhanging rock. One leg sticking out, visible in the sunlight.

[00:41:44]The discovery comes one month before Rosetta is scheduled to land on the comet and then shut down.

[00:41:54]During this final descent, scientists will perform last measures and extremely [music] detailed pictures will be taken.

[00:42:11]The last image uh transmitted we are at 80 m above surface. It's really get going down in warp speed now. And we get image by image higher in resolution. And then uh that's the last complete image that we shared at the day of landing because this is what we what popped up on the screen. [music] It this is the last image of Rosetta.

[00:42:34]The asteroid belt is much more than just comets and asteroids.

[00:42:40]NASA launched its dawn mission to explore the asteroid belt objects Vesta and seriesir in 2007.

[00:42:49]The Dawn mission is to explore these two [music] protolanets. They started forming as planets and stopped billions of years ago. So, it's kind of a snapshot of when the solar system formed.

[00:43:02]>> Nearly a decade later, Dawn is not only furthering our understanding of how icy and rocky planets are formed, but may also have delivered potential clues as to the [music] origins of life itself.

[00:43:16]Using cuttingedge ion propulsion technology, Dawn is the first spacecraft to orbit two extraterrestrial bodies in our solar system.

[00:43:27]Once the science at Vesta was completed, the futuristic craft would [music] travel almost 3 years to reach series.

[00:43:36]The ion propulsion system gave the probe unprecedented mobility.

[00:43:44]Out here in the vast asteroid belt, a lone dwarf planet looms large.

[00:43:50]Series, a body 590 m across, roughly the width of Texas, is changing our understanding of the asteroid belt. As new evidence suggests, it may hold the key to deciphering the early life of our solar system.

[00:44:09]While seriesir was expected to be a cold, hard rock besieged with craters, scientists have now been left scratching their heads.

[00:44:18]In February of 2017, they discovered something that could change everything they thought they knew of the asteroid belt.

[00:44:25]Organic molecules.

[00:44:30]This body has appeared just as a a faint smudge of light amidst the stars for more than two centuries. And now we're turning it into a richly detailed, fascinating portrait of a complex, fascinating alien world.

[00:44:46]>> Orbiting at an altitude of only 240 m above the rocky terrain, closer to series than the International Space Station is to Earth.

[00:44:58]Dawn's impressive [music] array of instruments are a testament to NASA's continued development of cutting edge technologies.

[00:45:06]>> The Dawn mission has a camera which takes visible light images of the surface which helps us understand what the body looks like. Helps us map [music] out the topography over the surface.

[00:45:19]Another instrument is the visible in infrared [music] spectrometer that provides the highresolution spectrum of the surface using the reflected light and that helps us understand the mineral makeup of the surface. The last [music] instrument on the spacecraft is the grand instrument, a gammaraya neutron detector which helps us [music] understand the mineral makeup all the way down to about a meter below the surface. uh because it looks at neutrons that come off of the surface when a [music] cosmic ray or something like that hits an atom on the surface. It bounces a [music] neutron up and the grand instrument can detect those and understand the mineral makeup.

[00:46:01]My colleague found a [music] spectral signature in her data that is consistent with or the same signature of of alifhatic [music] hydrocarbons. Now, that's a big long phrase, but what it means, it's chains of carbon and hydrogen atoms [music] together that are found in organic compounds in a number of different organic compounds. Methane um and ethane are two [music] alifhatic hydrocarbons.

[00:46:29]They're products of organic processes.

[00:46:33]So, here we're [music] finding maybe the building blocks of of biological material seen here in red. The organic [music] materials were found in an area covering roughly 400 square miles of what is known as theet crater and are thought to have originated in the dwarf planet itself.

[00:46:55]Had they been brought during an asteroid's impact on Siri's surface, the distribution would have been widespread instead of in the highly concentrated pockets observed by dawn.

[00:47:07]And while the actual composition of the molecules has yet to be confirmed, the spacecraft's instruments point to either kerite or asphaltite tarlike minerals found here on Earth.

[00:47:21]And it's not found in very many places [music] throughout the solar system. We only see these signatures on two other asteroids and on three of the moons of of Saturn. This is only the seventh place in the solar system where we see these compounds that [music] are are related to organic material. It doesn't mean that we found life there, but but if there is life there, it's it's the first clue.

[00:47:48]For life to form, an energy source would also have to be present. And Dawn may have found that evidence nearly 600 miles away at what has been dubbed the AAR crater.

[00:48:02]When dawn arrived at seriesir, we noticed this [music] very bright patch of reflected light off of the surface.

[00:48:09]And as we got closer and closer, the bright patch turned into a couple of patches.

[00:48:15]We got lower closer to the body, got higher resolution image data, and [music] finally were able to confirm that reflected light is coming from the mineral left behind from water melting or ice melting into vapor.

[00:48:31]The Auror Crater is a 57m wide zone with the highest concentration of carbonate minerals found outside of Earth.

[00:48:41]While not considered to be organic compounds, the discovery of these salt flats is just as important.

[00:48:48]Surprisingly, the bright area is estimated to be 30 million years younger than the crater itself and appears to have originated from series, pointing to geological activity.

[00:49:03]Evidence possibly supporting this theory can be found a short distance [music] away at a 2 and 1/2 mile high dome-shaped mountain known as a huna.

[00:49:14]Scientists now believe [music] that the feature could perhaps be a cryo volcano responsible for the release of sodium carbonates and salts.

[00:49:26]We hadn't seen [music] anything like it before in the solar system. It was very tall and had steep slopes. So if the hunamons [music] is a cryo volcano, which we have demonstrated that it is, that tells us that there has to be something beneath the [music] surface of series that heated the material to the melting point and made it push through the cracks [music] on the surface. Um, we're not sure what that material is.

[00:49:52]The temperatures [music] are so cold that the same type of of magma on Earth and Mars just doesn't can't exist on series. So the material that's flowing on series had to be composed of mostly very salty water that would flow at the low temperatures and when pushed out onto the surface they would freeze and form this steepsided dome called a hunamonds.

[00:50:21]But what surprises us is that this happened so recently. We expected series to be a cold rock. Um, but sure enough, here's the evidence that it is not. It's an active protolanet [music] and it's recently active and that's really surprising.

[00:50:39]The universal [music] constant in the search for life is always water. So, um, now we're looking at bodies like [music] series as places where, um, there may have been life in the past because they have the essential ingredients. [music] They had liquid water or do at the present. um they had essential chemical ingredients and they had [music] energy sources.

[00:51:03]>> Now that we've completed those objectives, we're going to raise [music] the orbit from our our lowest altitude where we are now to allow us to [music] conserve fuel to stay longer at series.

[00:51:13]That right now our plans take us through August of 2017 where we'll be at a higher orbit continuing [music] to observe series and and looking to improve our data set.

[00:51:25]series has gone above and beyond the expectations of NASA scientists. And with a few months of scientific exploration left to go, all the evidence suggests they only just scratched the surface.