For the second time in history, a human-made object has reached the space between the stars. NASA’s Voyager 2 probe now has exited the heliosphere – the protective bubble of particles and magnetic fields created by the Sun.
Members of NASA’s Voyager team will discuss the findings at a news conference at 11 a.m. EST (8 a.m. PST) today at the meeting of the American Geophysical Union (AGU) in Washington. The news conference will stream live on the agency’s website.
Comparing data from different instruments aboard the trailblazing spacecraft, mission scientists determined the probe crossed the outer edge of the heliosphere on Nov. 5. This boundary, called the heliopause, is where the tenuous, hot solar wind meets the cold, dense interstellar medium. Its twin, Voyager 1, crossed this boundary in 2012, but Voyager 2 carries a working instrument that will provide first-of-its-kind observations of the nature of this gateway into interstellar space.
Voyager 2 now is slightly more than 11 billion miles (18 billion kilometers) from Earth. Mission operators still can communicate with Voyager 2 as it enters this new phase of its journey, but information – moving at the speed of light – takes about 16.5 hours to travel from the spacecraft to Earth. By comparison, light traveling from the Sun takes about eight minutes to reach Earth.
The most compelling evidence of Voyager 2’s exit from the heliosphere came from its onboard Plasma Science Experiment (PLS), an instrument that stopped working on Voyager 1 in 1980, long before that probe crossed the heliopause. Until recently, the space surrounding Voyager 2 was filled predominantly with plasma flowing out from our Sun. This outflow, called the solar wind, creates a bubble – the heliosphere – that envelopes the planets in our solar system. The PLS uses the electrical current of the plasma to detect the speed, density, temperature, pressure and flux of the solar wind. The PLS aboard Voyager 2 observed a steep decline in the speed of the solar wind particles on Nov. 5. Since that date, the plasma instrument has observed no solar wind flow in the environment around Voyager 2, which makes mission scientists confident the probe has left the heliosphere.
In addition to the plasma data, Voyager’s science team members have seen evidence from three other onboard instruments – the cosmic ray subsystem, the low energy charged particle instrument and the magnetometer – that is consistent with the conclusion that Voyager 2 has crossed the heliopause. Voyager’s team members are eager to continue to study the data from these other onboard instruments to get a clearer picture of the environment through which Voyager 2 is traveling.
“There is still a lot to learn about the region of interstellar space immediately beyond the heliopause,” said Ed Stone, Voyager project scientist based at Caltech in Pasadena, California.
Together, the two Voyagers provide a detailed glimpse of how our heliosphere interacts with the constant interstellar wind flowing from beyond. Their observations complement data from NASA’s Interstellar Boundary Explorer (IBEX), a mission that is remotely sensing that boundary. NASA also is preparing an additional mission – the upcoming Interstellar Mapping and Acceleration Probe (IMAP), due to launch in 2024 – to capitalize on the Voyagers’ observations.
“Voyager has a very special place for us in our heliophysics fleet,” said Nicola Fox, director of the Heliophysics Division at NASA Headquarters. “Our studies start at the Sun and extend out to everything the solar wind touches. To have the Voyagers sending back information about the edge of the Sun’s influence gives us an unprecedented glimpse of truly uncharted territory.”
While the probes have left the heliosphere, Voyager 1 and Voyager 2 have not yet left the solar system, and won’t be leaving anytime soon. The boundary of the solar system is considered to be beyond the outer edge of the Oort Cloud, a collection of small objects that are still under the influence of the Sun’s gravity. The width of the Oort Cloud is not known precisely, but it is estimated to begin at about 1,000 astronomical units (AU) from the Sun and to extend to about 100,000 AU. One AU is the distance from the Sun to Earth. It will take about 300 years for Voyager 2 to reach the inner edge of the Oort Cloud and possibly 30,000 years to fly beyond it.
The Voyager probes are powered using heat from the decay of radioactive material, contained in a device called a radioisotope thermal generator (RTG). The power output of the RTGs diminishes by about four watts per year, which means that various parts of the Voyagers, including the cameras on both spacecraft, have been turned off over time to manage power.
“I think we’re all happy and relieved that the Voyager probes have both operated long enough to make it past this milestone,” said Suzanne Dodd, Voyager project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “This is what we’ve all been waiting for. Now we’re looking forward to what we’ll be able to learn from having both probes outside the heliopause.”
Voyager 2 launched in 1977, 16 days before Voyager 1, and both have traveled well beyond their original destinations. The spacecraft were built to last five years and conduct close-up studies of Jupiter and Saturn. However, as the mission continued, additional flybys of the two outermost giant planets, Uranus and Neptune, proved possible. As the spacecraft flew across the solar system, remote-control reprogramming was used to endow the Voyagers with greater capabilities than they possessed when they left Earth. Their two-planet mission became a four-planet mission. Their five-year lifespans have stretched to 41 years, making Voyager 2 NASA’s longest running mission.
The Voyager story has impacted not only generations of current and future scientists and engineers, but also Earth’s culture, including film, art and music. Each spacecraft carries a Golden Record of Earth sounds, pictures and messages. Since the spacecraft could last billions of years, these circular time capsules could one day be the only traces of human civilization.
Voyager’s mission controllers communicate with the probes using NASA’s Deep Space Network (DSN), a global system for communicating with interplanetary spacecraft. The DSN consists of three clusters of antennas in Goldstone, California; Madrid, Spain; and Canberra, Australia.
The Voyager Interstellar Mission is a part of NASA’s Heliophysics System Observatory, sponsored by the Heliophysics Division of NASA’s Science Mission Directorate in Washington. JPL built and operates the twin Voyager spacecraft. NASA’s DSN, managed by JPL, is an international network of antennas that supports interplanetary spacecraft missions and radio and radar astronomy observations for the exploration of the solar system and the universe. The network also supports selected Earth-orbiting missions. The Commonwealth Scientific and Industrial Research Organisation, Australia’s national science agency, operates both the Canberra Deep Space Communication Complex, part of the DSN, and the Parkes Observatory, which NASA has been using to downlink data from Voyager 2 since Nov. 8.
The voyager probes, launched in 1977, have already travelled nearly 17.7 billon kilometers (or 11 billion miles) into our solar system. NASA project scientists believe that it’s about to become the second man made object to leave the heliosphere and reach interstellar space. Voyager 1, it’s counterpart, was the first object to reach interstellar space.
“We’re seeing a change in the environment around Voyager 2, there’s no doubt about that. We’re going to learn a lot in the coming months, but we still don’t know when we’ll reach the heliopause. We’re not there yet – that’s one thing I can say with confidence.” says Ed Stone, Voyager project scientist.
Voyager 2 currently sits at the edge of the Heliosphere. The heliosphere is the bubble-like region of space dominated by the Sun, which extends far beyond the orbit of Pluto.
What the team is seeing with Voyager 2, resembles patterns seen in Voyager 1’s journey. In May 2012, Voyager 1 experienced an increase in the rate of cosmic rays similar to what Voyager 2 is now detecting. That was about three months before Voyager 1 crossed the heliopause and entered interstellar space.
However, Voyager team members note that the increase in cosmic rays is not a definitive sign that the probe is about to cross the heliopause. Voyager 2 is in a different location in the heliosheath — the outer region of the heliosphere — than Voyager 1 had been, and possible differences in these locations means Voyager 2 may experience a different exit timeline than Voyager 1.
The fact that Voyager 2 may be approaching the heliopause six years after Voyager 1 is also relevant, because the heliopause moves inward and outward during the Sun’s 11-year activity cycle. Solar activity refers to emissions from the Sun, including solar flares and eruptions of material called coronal mass ejections. During the 11-year solar cycle, the Sun reaches both a maximum and a minimum level of activity.
The Voyager spacecraft were built by NASA’s Jet Propulsion Laboratory in Pasadena, California, which continues to operate both. JPL is a division of Caltech. The Voyager missions are a part of the NASA Heliophysics System Observatory, managed by the Heliophysics Division of the Science Mission Directorate in Washington.
You can track Voyager’s progress right here.
A thrilling epoch in the exploration of our solar system came to a close today, as NASA’s Cassini spacecraft made a fateful plunge into the atmosphere of Saturn, ending its 13-year tour of the ringed planet.
“This is the final chapter of an amazing mission, but it’s also a new beginning,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate at NASA Headquarters in Washington. “Cassini’s discovery of ocean worlds at Titan and Enceladus changed everything, shaking our views to the core about surprising places to search for potential life beyond Earth.”
Telemetry received during the plunge indicates that, as expected, Cassini entered Saturn’s atmosphere with its thrusters firing to maintain stability, as it sent back a unique final set of science observations. Loss of contact with the Cassini spacecraft occurred at 7:55 a.m. EDT (4:55 a.m. PDT), with the signal received by NASA’s Deep Space Network antenna complex in Canberra, Australia.
“It’s a bittersweet, but fond, farewell to a mission that leaves behind an incredible wealth of discoveries that have changed our view of Saturn and our solar system, and will continue to shape future missions and research,” said Michael Watkins, director of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, which manages the Cassini mission for the agency. JPL also designed, developed and assembled the spacecraft.
Cassini’s plunge brings to a close a series of 22 weekly “Grand Finale” dives between Saturn and its rings, a feat never before attempted by any spacecraft.
“The Cassini operations team did an absolutely stellar job guiding the spacecraft to its noble end,” said Earl Maize, Cassini project manager at JPL. “From designing the trajectory seven years ago, to navigating through the 22 nail-biting plunges between Saturn and its rings, this is a crack shot group of scientists and engineers that scripted a fitting end to a great mission. What a way to go. Truly a blaze of glory.”
As planned, data from eight of Cassini’s science instruments was beamed back to Earth. Mission scientists will examine the spacecraft’s final observations in the coming weeks for new insights about Saturn, including hints about the planet’s formation and evolution, and processes occurring in its atmosphere.
“Things never will be quite the same for those of us on the Cassini team now that the spacecraft is no longer flying,” said Linda Spilker, Cassini project scientist at JPL. “But, we take comfort knowing that every time we look up at Saturn in the night sky, part of Cassini will be there, too.”
Cassini launched in 1997 from Cape Canaveral Air Force Station in Florida and arrived at Saturn in 2004. NASA extended its mission twice – first for two years, and then for seven more. The second mission extension provided dozens of flybys of the planet’s icy moons, using the spacecraft’s remaining rocket propellant along the way. Cassini finished its tour of the Saturn system with its Grand Finale, capped by Friday’s intentional plunge into the planet to ensure Saturn’s moons – particularly Enceladus, with its subsurface ocean and signs of hydrothermal activity – remain pristine for future exploration.
While the Cassini spacecraft is gone, its enormous collection of data about Saturn – the giant planet, its magnetosphere, rings and moons – will continue to yield new discoveries for decades to come.
“Cassini may be gone, but its scientific bounty will keep us occupied for many years,” Spilker said. “We’ve only scratched the surface of what we can learn from the mountain of data it has sent back over its lifetime.”
A space probe is a type of unmanned, unpiloted device that is sent to space to gather scientific information and explore. These probes have been sent to asteroids, all of the solar system’s planets, the moon and to comets.
The Different Types of Space Probes
There are three types of space probes, including orbiters, interplanetary and landers. In 2013, there were five probes on Mars alone, seeking to gather data about the planet.
How a Space Probe Travels
Space probes have been used to learn about outer space since the 1950s. Some will operate on the land of a planet while others go far out into the solar system. Some will go out to space and not return, while others will come back and deliver data and samples to scientists on Earth. In most cases, radio technology is used to transmit the data back to earth.
Space Probe History
On October 4, 1957, the first probe was sent into space and it was called Sputnik 1. The former Soviet Union launched it. It was in 1958 when the United States sent Explorer 1, another probe, into space. These two probes focused on learning more about Earth from the perspective of space. They also provided information about what being in space was like. In 1962, a probe called Mariner 2 became the first to examine another planet and its focus was on Venus. It was able to tell scientists that this planet was indeed very hot in terms of temperature.
The space probe is another tool that scientists have to help solve the mysteries of space. It also makes it possible for people to keep an eye on the events of the solar system, and to determine when massive changes happen or new discoveries are made.
The 20-year mission is coming to an end later this month when the probe makes its final destructive plunge into Saturn.
As part of its grand finale, Cassini has flown closer to the rings than ever before, first grazing the outermost edges of the rings before taking the risky leap of diving through the gap between the rings and Saturn.
Saturn’s big empty
One of the surprises was that it’s quite empty in this gap. This is very different to when Cassini was bombarded by hundreds of dust particles per second as it moved past the outer rings late last year.
But it meant good news for the mission as this final stage had a better chance for success if there was less material in the way.
During a recent ring dive in August, instead of orientating Cassini so that it flew antenna-first through the gap (offering it more protection), the spacecraft was turned around allowing it to capture a fantastic view of the rings as it dived past.
Know your ring ABCs
Over the centuries, as Saturn’s rings have been observed in finer detail, they have been broken into discrete sections. They are named alphabetically in order of discovery, which means from innermost to outermost the order is D, C, B, A, F, G and E.
Saturn’s innermost ring D is much less dense and therefore fainter than its neighbouring ring C.
By comparing new Cassini images of the D ring with its original discovery image from Voyager in 1980, it’s possible to see changes in the ring over a relatively short period of time.
In the Voyager image, three relatively bright arcs can be seen in the D ring (the bright arc in the lower left of frame is the C ring). Most dramatically, the central and brightest arc has faded markedly and moved 200km closer to Saturn (the arc no longer lines up with the Voyager image).
Origin of the rings
We know that the rings are mostly made of water ice, but it’s not clear how they formed or even how old they are.
The fact that they are still bright, rather than coated in dust, suggests a young age – perhaps just 100 million years old, placing their formation in the time of the dinosaurs.
This is consistent with Cassini data, but this theory also presents a problem: it means that a previous collection of moons had a fairly recent and mighty smash-up, creating the rings and five of Saturn’s current-day moons.
Alternatively, Cassini has also shown that there is a lot less dust entering the Saturn system than was originally expected. This makes it possible for the rings to be both ancient and bright, having formed early in the life of the Solar System. Furthermore, interactions within the rings might dust them off and keep them looking young.
Finger on the source
For Saturn’s outermost E ring the source is pretty clear. The moon Enceladus orbits within this ring and Cassini observations have directly traced features in the ring back to geysers erupting from Enceladus’s surface.
Prometheus interacts with the ring once every orbit, when it reaches the point that takes it furthest away from Saturn and closest to the F ring. As Prometheus orbits faster than the ring material, a new streamer is created that is ahead of the old one with every orbit.
Several of Saturn’s smaller moons reside within and carve out gaps in the rings, and Cassini has shown them to have bulges around their middles.
The moon Pan was responsible for clearing the A ring’s large Encke Gap. As it collects the ring material, Pan’s gravity is not strong enough to spread the accumulated matter across its surface, and instead a striking ridge develops.
The tiny moon Daphnis is one of seven moons newly discovered by Cassini. It is just 8km across and as it orbits inside the A ring’s small Keeler Gap, it pulls on the ring particles leaving waves in its wake.
Turning rings into moons
The newly formed object is probably less than a kilometre across but being able to see such a process in action was a complete surprise for Cassini scientists.
It supports the theory that long ago, Saturn’s rings could have been much more massive and capable of producing some of the moons that exist today.
It also potentially provides insight into how the planets of the solar system formed, emerging out of the accretion disk that once orbited the young Sun.
Cassini has certainly achieved its mission objectives to explore Saturn, its atmosphere, magnetosphere and rings and to study Saturn’s moons, particularly Titan. So much has been learned, including the ability to gaze with wonder and awe at the amazing Solar System we are part of.
The Cassini space probe mission is coming to an end this month when the probe makes its final destructive plunge in to Saturn. It’s spent the past thirteen years studying the planet, its rings and moons in unprecedented detail.
Cassini wasn’t the first NASA probe to study Saturn close-up. Pioneer 11 (1979), Voyager 1 (1980) and Voyager 2 (1981) had flown by Saturn earlier, not stopping but giving us the opportunity to see the planet as the amazing world that it is.
But to really understand a planet, you need to spend time with it and that’s what Cassini has done.
Launched in 1997, it took almost seven years to reach Saturn, entering orbit on July 1, 2004. On Christmas Day that year, the Huygens probe was released towards Titan, the first probe ever to land on an object in the outer Solar System.
Cassini was on a four year mission to explore Saturn, its atmosphere, magnetosphere, rings and to study Saturn’s moons, especially Titan the only moon in the Solar System to have a substantial atmosphere.
Time goes by and seasons change
But four years has quickly grown into 13 impressive years, allowing Cassini to watch the slow progression of Saturn’s changing seasons.
When the spacecraft arrived, Saturn’s northern hemisphere was in the dark of winter.
The northern part of Saturn was a mesmerising blue. Less sunlight, particularly the Sun’s harsh ultraviolet rays, could reach the north leaving the atmosphere clear of smog and giving rise to the beautiful blue scattered light.
In August 2009, Cassini had the opportunity to view Saturn at equinox, a special time when the Sun sits directly in line with the planet’s rings. The only light hitting the rings is reflected light from Saturn itself.
During this time shadows were seen dancing across the rings. On average, the rings are very thin, just ten metres or so in thickness, and each of the rings and gaps in the rings have a special name.
At the edge of Saturn’s B ring, the equinox shadows revealed structures that towered as high as 2.5 kilometres. Quite possibly, small moonlets are splashing the ring particles about and forcing them upwards as the moonlets pass by.
As Cassini’s mission comes to an end, summer has arrived at Saturn’s north. The colours are changing and right at the top of Saturn’s north pole, it’s possible to see the distinctive hexagon – a six-sided weather pattern that is now bathed in sunlight.
Embedded in the heart of the hexagon is a roaring hurricane, 50 times larger than any hurricane experienced on Earth. Simulations suggest that it is produced by a jet stream curving around Saturn’s north pole and being jostled about as it interacts with other air currents.
Whatever established the hexagon, it’s certainly long-lived. The pattern was first recorded by the Voyager spacecraft in 1980, although it was not discovered in the data until eight years later.
Pink dancing lights
The Hubble Space Telescope has captured strong aurora on Saturn at ultraviolet wavelengths. But for the first time, Cassini has shown us Saturn’s northern and southern lights shimmering above the planet in visible light.
Unlike Earth’s aurora which are predominantly green and blue due to the oxygen and nitrogen in our atmosphere, Saturn’s aurora vary from pink to purple as charged particles collide and excite the hydrogen-rich atmosphere.
Scientists pay tribute to Cassini
It has involved 17 countries, 260 scientists plus thousands more who worked to design, build and launch the spacecraft.
Team members who have spent their careers working on the Cassini mission reflect on the epic journey. So farewell Cassini, what an amazing time it’s been.
Coming soon I’ll take a closer look at Cassini’s observations of many of the known moon’s of Saturn as well as the space probe’s new discoveries.
A false-color view of Saturn’s rings as the Cassini spacecraft stares towards the horizon. You can see Saturn’s stratosphere in this image as a thin haze that vanishes towards the left side of the frame.
This image composite was created using red, green, and ultraviolet spectral filters. They were obtained by the Cassini spacecraft narrow-angle camera on July 16, 2017, at a distance of about 777,000 miles (1.25 million kilometers) from Saturn. The scale of the image you are seeing is 4 miles (7 kilometers) per pixel on Saturn.
On Sept. 15, 2017 Cassini will pass through the upper atmosphere of saturn in the final five orbits of its mission – before making a final descent into the planet on the 15th. Cassini will fly through the stratosphere (directly above the haze seen in the image) and is expected to lost contact before it completes the journey through said haze.
Cassini, is operated in part by NASA, ESA (the European Space Agency) and the Italian Space Agency. It is managed by The Jet Propulsion Laboratory, a division of Caltech in Pasadena.
NASA’s Juno spacecraft recently completed a fly-by of Jupiter‘s great red spot, on July 10th. It was our closest orbit of the giant storm to date.
Raw images from the fly-by have since been posted on the JunoCam site and have begun to be processed by citizen scientists and amateur photoshop artists around the world. Our image above comes to you from citizen scientist Jason Major, a graphic designer from Warwick, Rhode Island.
“For hundreds of years scientists have been observing, wondering and theorizing about Jupiter’s Great Red Spot,”
The great red spot has always been a spot of intrigue for researchers. It’s a storm that has raged for over 350 years with no apparent end in site. It 10,159 miles (16,350 kilometers) wide, and has been monitored since 1830. “For hundreds of years scientists have been observing, wondering and theorizing about Jupiter’s Great Red Spot,” says Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. “Now we have the best pictures ever of this iconic storm. It will take us some time to analyze all the data from not only JunoCam, but Juno’s eight science instruments, to shed some new light on the past, present and future of the Great Red Spot.”
Perijove is the point at which an orbit come’s closest to Jupiter’s center. Juno reached Perijove on July 10th, at from 2,200 miles (3,500 kilometers) above the planet’s cloud surface. Once it had reached this point, it traversed 24,713 miles (39,771 kilometers) in eleven minutes to rest 5,600 miles (9,000 kilometers) above the great red spot.
The Juno mission began with a launch on August 5th 2011. Since it’s launch from Cape Canaveral we’ve studied Jupiter’s cloud tops, it’s auroras, planetary origins, structure, atmosphere and more. Today we see Jupiter as a complex world with significant weather patterns and a mysterious interior structure. Thanks to Juno, we know more about the planet than we ever have, and will continue to glean new interesting facts from the largest planet in our solar system.
“These highly-anticipated images of Jupiter’s Great Red Spot are the ‘perfect storm’ of art and science. With data from Voyager, Galileo, New Horizons, Hubble and now Juno, we have a better understanding of the composition and evolution of this iconic feature,” said Jim Green, NASA’s director of planetary science. “We are pleased to share the beauty and excitement of space science with everyone.”
NASA’s JunoCam recently released this striking image of Jupiter with storm formations resembling a face.
The shot is being dubbed ‘The Face of Jupiter” or “Jupiter’s Face” or “Jovey McJupiterface” It’s already giving the man on the moon a run for his money.
The original image was acquired by JunoCam on NASA’s Juno spacecraft on May 19, 2017 at 11:20 a.m. PT (2: 20 p.m. ET) from an altitude of 12,075 miles (19,433 kilometers). It was processed by citizen scientist Jason Major.
NASA’s orbiter Cassini will make a series of decreasing orbits that will end in a fiery death dive into Saturn’s atmosphere in September. This deliberate termination of a still serviceable spacecraft is to comply with “planetary protection” protocols, designed to minimise the risk of depositing stowaway Earth microbes into an environment where they might be able to reproduce.
The particular fear in this case is that if Cassini were allowed to become derelict in orbit it might eventually crash into Enceladus – a moon of Saturn now realised to have a watery interior that is eminently habitable for microbes. By similar reasoning, NASA’s first Jupiter orbiter Galileo was made to burn up in the planet’s atmosphere in 2003 rather than risk a future crash into its microbially habitable moon Europa. The same fate awaits Juno in February 2018.
This makes sense. When we eventually send landers capable of detecting life, it would be frustrating and potentially misleading if all they found was the descendants of microbes that we’d accidentally sent there ourselves. Apart from the science, there is the ethical question of whether we ought to “contaminate” alien ecosystems with bugs from Earth.
Cleanliness is next to impossible
You might think this risk could be eliminated by ensuring that the relevant spacecraft are scrupulously clean to begin with. However, despite using plasma (matter composed of electrically charged particles), intense radiation and heat to sterilise the components, and using special “clean rooms” to assemble them, it has proved impossible to construct a microbe-free spacecraft. The heat, cold, vacuum and harsh radiation encountered during spaceflight will kill most of them, but some will probably remain alive long enough to reach the destination. Experiments on the International Space Station have proved that spore-forming bacteria can remain viable in space for at least as long as it takes to get to Mars.
The international regulatory body COSPAR (Committee on Space Research) recognises the problem, and has protocols governing missions travelling from the surface of one planetary body to another. These accept that the risk of accidental contamination cannot be entirely eliminated, and specify a maximum risk that can be tolerated in each circumstance. NASA adheres to these rules and other space-faring nations, including China, are signatories too.
The rules say that no Mars lander may carry more than 300,000 spores on its surface. A lander sent to a “special region”, where organisms might be able to feed and reproduce, has a much smaller permissible maximum of just 30. The logic is that 30 spores adhering to a spacecraft’s surface would be too few to cause contamination.
For missions to Europa, which is thought to be the most habitable place in the solar system, the requirements are framed differently. They stipulate that the chances of inadvertent contamination of its internal ocean must be less than one in 10,000 per mission.
None of these rules have any force in law, and there are fears that they are liable to be be bent or broken on cost-saving grounds. Rather than leave them in place to be broken accidentally or deliberately breached by a “rogue” space agency, it would be better to have less stringent but more practicable protocols.
Certainly, as soon as you start sending humans to the surface of Mars, even the 300,000 spores rule goes (almost literally) out of the window. There are billions of microbes living on your skin, and also on the skin of even the best-scrubbed Mars astronaut. As soon as an airlock is flushed, or a spacesuit that has been handled by a human touches the martian soil, some of these bugs will be out there, released into the atmosphere. Don’t forget also that these humans will be going to the toilet. Although they will be recycling their urine, their solid wastes will almost certainly be left on the planet to lighten the load for take-off back to space.
The COSPAR policy recognises these issues, in a hand-wringy sort of way. It requires humans to avoid “special regions” of Mars (including where liquid water is suspected at or near the surface), until a “comprehensive planetary protection protocol for human missions” has been developed. However, any human mission to Mars – whether it goes to plan or miscarries as in the recent book and film The Martian – would almost certainly have to break the rules.
What’s more, it is possible that much of the caution, at least where Mars is concerned, is unnecessary. There may already be Mars microbes on Earth, and also microbes from Earth on Mars. Though landers are unlikely to have caused this, these two planets orbit sufficiently close to each other that debris thrown up by asteroid impacts can make the journey from one to the other and then rain down as meteorites, carrying potentially viable microbes.
If we do eventually find life on Mars, we will want to be able to distinguish between the alternative possibilities of a common origin versus two independent origins. This means we must try to avoid accidental contamination that might confuse the evidence.
But we have to ask ourselves whether the current rules are too strict. Eventual contamination is inevitable, unless we give up completely.
CAPE CANAVERAL, Fla. (Reuters) – A U.S. spacecraft set to launch next year will make a series of unprecedented dives in the sun’s scorching atmosphere to see how the star works and what can be done to better predict space weather events on Earth, scientists said on Wednesday.
The Parker Solar Probe will have to survive temperatures as high as 2,500 Fahrenheit (1,371 Celsius), impacts by supersonic particles and powerful radiation as it circles as close as 4 million miles (7 million km) to the sun.
Data sent back to Earth some 89 million miles (1.4 billion km) away will help scientists figure out why the sun’s atmosphere, or corona, is hotter than its surface.
“We’re going to be seven times closer (to the sun) than any other mission has ever been,” project scientist Nicola Fox, with Johns Hopkins University Applied Physics Laboratory in Maryland, said during a broadcast on NASA TV.
The mission, formerly known as the Solar Probe Plus, was approved in 2014. On Wednesday, the spacecraft was renamed to honor University of Chicago physicist Eugene Parker, who in 1958 correctly predicted the existence of the solar wind, a continuous stream of charged particles that come off the sun and permeate the solar system.
“It was a fundamental insight that forever changed the way in which we understood the sun, the heliosphere and in general interplanetary space,” said Eric Isaacs, executive vice president for research, innovation and national laboratories at the University of Chicago.
The spacecraft, designed and built by the Johns Hopkins University laboratory, is scheduled to launch in July 2018 and fly around Venus seven times to get itself into orbit around the sun in December 2024. NASA is paying about $1.5 billion to build and launch the spacecraft.
The probe is expected to orbit the sun 24 times, edging closer on each pass. The size of a small car, it will be outfitted with five science instruments to measure and sample the sun’s corona.
In addition to expanding knowledge of stellar physics, the information is expected to help engineers design better instruments and techniques for predicting solar storms and other events that can cripple satellites, disrupt power grids and affect aircraft travel on Earth.
“We want to measure the environment there and find what the heating processes really are that make the corona hot and accelerate the solar wind,” said NASA chief scientist Thomas Zurbuchen.
(Reporting by Irene Klotz; Editing by Colleen Jenkins and Lisa Shumaker)
Earth lives in its own little bubble so to speak, cut off from the vast majority of the universe due to the Sun’s solar wind. This forms the heliosphere, a spherical bubble. This bubble was previously thought to have a long tail, but is now thought to be smaller and rounder.
The sun’s magnetic field is controlled by high-speed particles, or wind. This wind creates pressure, producing a bubble known as the heliosphere. The sphere holds the interstellar medium. Part of the reason the Voyager 1 was such a significant journey was that it passed beyond the heliosphere and into interstellar space. This breakthrough helped scientists measure the heliosphere’s boundaries in two directions.
Rethinking the Size and Shape of the Heliosphere
A recent article in Nature Astronomy spoke about the redefining of the heliosphere’s shape. Instead of having a comet-like tail, the heliosphere is a strong bubble with a powerful magnetic field. While this makes the heliosphere stronger, it also makes it much smaller than previously thought.
Most of the evidence comes directly from the Cassini spacecraft. The data the unmanned spaceship is collecting on its travels is nowhere near the edge of our heliosphere. While the spaceship is mostly designed to collect data, it is also being used to analyze partials trapped within Saturn’s magnetosphere.
The sun has an 11-year cycle, with a 2 to 3 year delay. The strength of the solar wind depends on where the sun is in the cycle and how the neutral atoms are bouncing back and forth, Astronomers previously believed that the delay formed a trailing heliosphere, rather than a circle.
Studies in the past have tried to challenge heliosphere theories. While a 2009 study suggested the spherical shape, these reports lacked any concrete evidence until the Cassini’s data had been pulled. This is a huge way to end its orbit around Saturn before returning to Earth.
CAPE CANAVERAL, Fla. (Reuters) – NASA’s Cassini spacecraft sent the closest-ever images of Saturn on Thursday after surviving its first plunge inside the planet’s rings, the U.S. space agency said.
A stream of pictures showing Saturn’s swirling clouds, massive hurricane and odd six-sided vortex weather system were transmitted back to Earth by Cassini, which has been exploring Saturn for 13 years.
Now in its final laps around Saturn, Cassini dove through the narrow gap between the planet and its innermost ring on Wednesday, where no spacecraft has ever gone before. It was the first of 22 planned close encounters to bring the robotic probe into unexplored territory between Saturn’s cloud tops and its rings.
“Cassini spacecraft has once again blazed a trail, showing us new wonders and demonstrating where our curiosity can take us if we dare,” National Aeronautics and Space Administration planetary sciences chief Jim Green said in a statement.
Cassini is expected to photograph several small inner moons and study the planet’s winds, clouds, auroras and gravity. The information could help scientists find the source of Saturn’s magnetic field, determine how fast the gas giant rotates and figure out what lies beneath its layers of clouds.
NASA officials are not certain Cassini will survive all its ring dives. The gap between Saturn and the rings is about 1,500 miles (2,400 km) wide and likely littered with ice particles.
Cassini is traveling through the gap at a relative speed of about some 77,000 mph (124,000 kph) so even small particles striking the spacecraft can be deadly.
To protect itself, Cassini’s dish-shaped communications antenna was temporarily repositioned to serve as a shield. The spacecraft will make similar maneuvers during its subsequent dives, the next of which is scheduled for Tuesday.
On its final dive on Sept. 15, Cassini is slated to destroy itself by flying directly into Saturn’s crushing atmosphere.
During its first pass inside the rings, Cassini came within about 1,900 miles (3,000 km) from the top of Saturn’s clouds and within 200 miles (300 km) of its innermost ring.
Cassini has been probing Saturn, the sixth planet from the sun, and its entourage of 62 known moons since July 2004, but is running low on fuel.
NASA plans to crash the spacecraft into Saturn to avoid any chance Cassini could someday collide with any ocean-bearing moons that have the potential to support indigenous microbial life.
(Reporting by Irene Klotz; Editing by Letitia Stein and Jonathan Oatis)
CAPE CANAVERAL, Fla. (Reuters) – NASA’s Cassini spacecraft soared past Saturn’s biggest moon for the last time on Saturday, tapping its gravity to slingshot into a series of exploratory dives inside the planet’s rings, followed by a final fatal plunge into the gas giant.
After nearly 20 years of traveling in space, Cassini used the gravitational tug of Titan, a moon resembling primordial Earth, to hurl itself into a new orbit that will pass through an unexplored region between Saturn’s cloud tops and its rings.
The spacecraft is expected to make the first of 22 dives between the planet and its rings on Wednesday. During the last dive on Sept. 15, Cassini is slated to destroy itself by flying directly into Saturn’s crushing atmosphere.
Cassini’s final run was set into motion early on Saturday by its 127th and final pass by Titan, the U.S. National Aeronautics and Space Administration said.
At its closest approach, NASA projections had Cassini flying 608 miles (979 km) above Titan, zipping by at a relative speed of 13,000 miles per hour (21,000 km per hour).
“Titan’s gravity will bend Cassini’s orbit around Saturn, shrinking it slightly, so that instead of passing just outside the rings, the spacecraft will begin its finale dives which pass just inside the rings,” NASA said in a statement on Wednesday.
During the dives, Cassini will measure how much ice and other materials are in the rings and determine their chemical composition. That information will help scientists learn how the rings formed.
Cassini also will study Saturn’s atmosphere and take measurements to determine the size of the planet’s rocky core.
Cassini has been probing Saturn, the sixth planet from the sun, and its entourage of 62 known moons since July 2004, but is running low on fuel.
NASA plans to crash the spacecraft into Saturn to avoid any chance Cassini could someday collide with Titan, the ocean-bearing moon Enceladus or any other moon that has the potential to support indigenous microbial life.
By destroying the spacecraft, NASA will ensure that any hitchhiking Earth microbes still alive on Cassini will not contaminate the moons for future study.
(Reporting by Irene Klotz; Editing by Letitia Stein and Jonathan Oatis)
These raw, unprocessed images of Saturn’s tiny moon, Pan, were taken on March 7, 2017, by NASA’s Cassini spacecraft. The flyby had a close-approach distance of 24,572 kilometers (15,268 miles).
These images are the closest images ever taken of Pan and will help to characterize its shape and geology.
(Reuters) – A U.S. science satellite slated to launch to Mars in March has been grounded due to a leak in a key research instrument, NASA said on Tuesday, creating uncertainty about the future of a widely anticipated effort to study the interior of the planet.
The spacecraft, known as InSight, was designed to help scientists learn more about the formation of rocky planets, including Earth.
The cancellation raises questions about the future of the research effort, as it will be another 26 months before Earth and Mars are favorably aligned for a launch.
Over the next couple of months, NASA will assess options for repairing the faulty instrument, a sensitive seismometer that was provided by the French space agency, CNES.
Budgetary limits may factor into a pending decision on whether NASA will proceed with the program.
After landing on Mars, InSight was designed to detect quakes and other seismic activities, as well as measure how much heat is being released from the planet’s subsurface and monitor Mars’ wobble – or variations in its orbit – as it circles the sun.
The troubled seismometer, which detects minute vibrations, features sensors encased in a nine-inch (23-cm) wide vacuum sphere, which has been plagued by a series of leaks since August.
Engineers believed they had fixed the problems, but another leak surfaced on Monday during testing.
“We just don’t have enough time to find the leak, fix it and still make it to the launch pad in March,” John Grunsfeld, NASA associate administrator for science, said during a phone call with reporters.
InSight arrived last week at Vandenberg Air Force Base in California to begin preparations ahead of a launch targeted for March 18.
The costs for the InSight mission, including launch and data analysis, are capped at $675 million, up from an initial $425 million, NASA Planetary Sciences Division Director Jim Green told reporters.
So far, the U.S. space agency has spent $525 million on the program, including buying an Atlas 5 rocket from United Launch Alliance, a partnership of Lockheed Martin and Boeing.
By Irene Klotz
(Reporting by Irene Klotz in Tel Aviv; Editing by Letitia Stein and Alan Crosby)
Apparently, it’s all about mining asteroids and using the material to construct the Death Star in orbit.
In a video appearing on Wired, Brian Muirhead, the chief engineer at NASA’s Jet Propulsion Laboratory, speaks on the Asteroid Redirect Mission. The asteroid redirect mission will be examining the possibility of asteroid mining in orbit. The eventual result of the mission will be capture a boulder with a specifically designed probe and carry it into lunar orbit where groups of astronauts can visit to mine asteroid materials. Ideally, this mission will take place in 2023.
Muirhead’s research won’t exactly teach us how to build a Death Star in orbit, but it may give us insight as to how we can build a megastructure around our own planet. Watch below as he breaks down the science behind asteroid mining and building such a massive structure:
The Death Star has a radius of 60 kilometers (37 miles), this corresponds to a total volume of 904,000 cubic kilometers (217,000 cubic miles) and has an estimated mass of 190 trillion tonnes (according to Wookiepedia). The cost of sending items into space is roughly $20,000 per kilogram, this means that assembling the Death Star would cost us approximately 40,000 billion billion dollars; a number that dwarfs planet earth’s economy by a factor of a billion.
The asteroid redirect mission will capture a space rock that weighs 450,000 kilograms or 500 tons, and will cost approximately $2.6 billion. At this scale, you can see how costly it would be to build a Death Star that weighs over 190 trillion tonnes.
We may not see a Death Star around our planet any time soon, but thanks to the Asteroid Redirect Mission, we might be fortunate to lay the groundwork for the ability to harness materials in space, the first step to building structures in orbit.
NASA and Johns Hopkins University are working on plans for a probe that will have the ability to touch the surface of the sun.
Known as NASA’s Solar Probe Plus, the probe is currently being built at a cost of $1.5 billion in technology that will carry an array of sensors aimed at the Sun’s corona. The aim, is for the probe to survive temperatures of up to 2,500 degrees Fahrenheit in order to collect data for future scientific use cases.
Ralph McNutt of Johns Hopkins, one of the leaders of the team, says that creating a spacecraft to survive in such harsh conditions requires scientific mastery:
At its very closest approach of only 3.8 million miles from the Sun’s surface, SPP will be subjected to up to 475 times the solar irradiance experienced at Earth. Thus, the science collection phases of the mission during close encounters are designed to be autonomous. That is, without real-time direction from ground-controllers.
Data taken during these collection phases will be saved on solid state recorders for subsequent downlink via a high gain antenna pointed back to Earth.
The probe’s thermal protection system is an 8-foot-diameter, 4.5-inch-thick, carbon-carbon, carbon foam shield that sits atop the spacecraft. Basically, most of the entire spacecraft “hides” behind this shield during the spacecraft’s closest approach to the Sun, says McNutt.
The probe is being built by NASA with full assistance from the Applied Physics Lab at Johns Hopkins University, as well a variety of other participating institutes. Solar Probe Plus is expected to launch in 2018.
See below for an artist conception of Solar Probe Plus
Image Credit: NASA