Space and astronomy news
Welcome to the 558th Carnival of Space! The Carnival is a community of space science and astronomy writers and bloggers, who submit their best work each week for your benefit. We have a fantastic roundup today, so now, on to this week’s stories!
Continue reading “Carnival of Space #558”
In September of 2016, Elon Musk announced the latest addition to the SpaceX rocket family. Known then as the Interplanetary Transport System (ITS) – now know as the Big Falcon Rocket (BFR) – this massive launch vehicle is central to Musk’s vision of sending astronauts and colonists to Mars someday. Since that time, the space community has eagerly waited for any news on how the preparations for this rocket are going.
Musk further inflamed people’s anticipation by recently announcing that the BFR would be ready to conduct orbital flights by as early as 2020. While admittedly an optimistic deadline, Musk indicated that his company was building the presently building the ship. And according to a recent post on Musk’s Instagram account, a key component (the main body tool) for making the BFR interplanetary spaceship has just been completed.
It is important to note, however, that what is being shown here is not actually a part of the rocket. As Ryan Whitwam of Extreme Tech noted, what we are seeing in the post is a tool “that SpaceX will use to fabricate the rocket from carbon fiber composite materials that are lighter than traditional materials. Flexible resin sheets of carbon fiber will be layered on the tool and then heated to cure them. After heating, you’re left with a solid section of rocket fuselage. It’s essentially a carbon fiber jig.”
https://www.instagram.com/p/BhVk3y3A0yB/?hl=en
Nevertheless, from the size of the tool itself, one gets a pretty clear idea of how large the final rocket will be. SpaceX chose to illustrate the scale of the tool by placing a Tesla next to it for scale. For some additional perspective, consider the cherry Tesla Roadster (driven by Starman) SpaceX launched with the Falcon Heavy‘s maiden flight.
Whereas the payload capsule was barely large enough to house it, this car looks like it could fit inside any rocket turned out by this tool easily, and with plenty of room to spare. And while cars are not exactly the BFR’s intended payload, it is good to know that it will be no slouch in that department!
When completed, the BFR will be the largest and most powerful rocket in the SpaceX rocket family. According to the company’s own specifications, it will measure 106 meters (348 ft) in height and 9 meters (30 ft) in diameter and will be able to deliver a payload of 150,000 kg (330,000 lb) to Low-Earth Orbit (LEO) – almost two and a half times the payload of the Falcon Heavy (63,800 kg; 140,660 lb).
And as Musk indicated during an interview with Jonathon Nolan at the 2018 South by Southwest Conference (SXSW) in Austin, Texas, it will even outpace the rockets that won the Space Race for the US:
“This a very big booster and ship. The liftoff thrust of this would be about twice that of a Saturn V (the rockets that sent the Apollo astronauts to the Moon). So it’s capable of doing 150 metric tons to orbit and be fully reusable. So the expendable payload is about double that number.”
Once completed, Musk hopes to see the BFR performing service missions to Low-Earth Orbit (LEO), the International Space Station, to the Moon, and – of course – to Mars. In addition to sending colonists there as early as the next decade, Musk has also expressed interest in using the BFR to conduct space tourism – flying passengers in luxury accommodations to the Red Planet and back.
In the end, it is clear that Musk and the company he founded for the purpose of reigniting space exploration are determined to make all of this happen. In the coming years, it will be interesting to see how far and how fast they progress.
Further Reading: Instagram, SpaceX, Extreme Tech
Since it landed on Mars in 2012, the Curiosity rover has made some rather startling scientific discoveries. These include the discovery of methane and organic molecules, evidence of how it lost its ancient atmosphere, and confirming that Mars once had flowing water and lakes on its surface. In addition, the rover has passed a number of impressive milestones along the way.
In fact, back in January of 2018, the rover had spent a total of 2,000 Earth days on Mars. And as of March 22nd, 2018, NASA’s Mars Curiosity rover had reached its two-thousandth Martian day (Sol) on the Red Planet! To mark the occasion, NASA released a mosaic photo that previews what the rover will be investigating next (hint: it could shed further light on whether or not Mars was habitable in the past).
The image (shown at top and below) was assembled from dozens of images taken by Curiosity‘s Mast Camera (Mastcam) on Sol 1931 (back in January). To the right, looming in the background, is Mount Sharp, the central peak in the Gale Crater (where Curiosity landed back in 2012). Since September of 2014, the rover has been climbing this feature and collecting drill samples to get a better understanding of Mars’ geological history.
In the center of the image is the rover’s next destination and scientific target. This area, which scientists have been studying from orbit, is rich in clay minerals, which indicates that water once existed there. In the past, the Curiosity rover found evidence of clay minerals on the floor of the Gale Crater. This confirmed that the crater was a lake bed between 3.3 and 3.8 billion years ago.
Mount Sharp, meanwhile, is believed to have formed from sedimentary material that was deposited over a period of about 2 billion years. By examining patches of clay minerals that extend up the mountain’s side, scientists hope to gain insight into the history of Mars since then. These include how long water may have persisted on its surface and how the planet made the transition to the cold and desiccated place it is today.
The Curiosity science team is eager to analyze rock samples pulled from the clay-bearing rocks seen in the center of the image, and not just because of the results they could provide. Recently, the science team developed a new drilling technique to compensate for the failure of a faulty motor (which allows the drill to extend and retract). When the rover begins to drill again, it will be the first time since December 2016.
All told, the rover has spent a total of about 2055 Earth days (5 years and 230 days), which means Curiosity now ranks third behind the Opportunity (5170 days; 5031 sols) and the Spirit rovers (2269 days; 2208 sols) in terms of total time spent on Mars. Since it arrived on Mars in 2012, Curiosity has also traveled a total distance of 18.7 km (11.6 mi) and studied more than 180 meters (600 feet) vertical feet of rock.
But above all, Curiosity‘s greatest achievement has been the discovery that Mars once had all the necessary conditions and chemical ingredients to support microbial life. Based on their findings, Curiosity‘s international science team has concluded that habitable conditions must have lasted for at least millions of years before Mars’ atmosphere was stripped away.
Finding the evidence of this, and how the transition occurred, will not only advance our understanding of the history of Mars, but of the Solar System itself. It also might provide clues as to how Mars could be made into a warmer, wetter environment again someday!
Further Reading: NASA
For some time, scientists have known that the Moon and Mars have some fascinating similarities to Earth. In addition to being similar in composition, there is ample evidence that both bodies had active geological pasts. This includes stable lava tubes which are very similar to those that exist here on Earth. And in the future, these tubes could be an ideal location for outposts and colonies.
However, before we can begin choosing where to settle, these locations need to be mapped out to determining which would be suitable for human habitation. Luckily, a team of speleologists (cave specialists), geologists and ESA astronauts recently created the largest 3D image of a lava tube ever created. As part of the ESA’s PANGAEA program, this technology could one day help scientists map out cave systems on the Moon and Mars.
The lava tube in question was the La Cueva de Los Verdes, a famous tourist destination in Lanzarote, Spain. In addition to ESA astronaut Matthias Mauer, the team consisted of Tommaso Santagata (a speleologist from the University of Padova and the co-founder of the Virtual Geographic Agency), Umberto Del Vecchio and Marta Lazzaroni – a geologists and a masters student from the University of Padova, respectively.
Last year, the team mapped the path of this cave system as part of the ESA’s 2017 Pangaea-X campaign. As one of many ESA Spaceflight Analog field campaigns, the purpose of Pangaea-X is to conduct experiments designed to improve the future of the ESA’s Planetary ANalogue Geological and Astrobiological Exercise for Astronauts (PANGAEA) training course.
For five days in November 2017, this campaign mobilized 50 people, four space agencies and 18 organizations in five different locations. The La Cueva de los Verdes lava tube was of particular importance since it is one of the world’s largest volcanic cave complexes, measuring roughly 8 km in length. Some of these caves are even large enough to accommodate residential streets and houses.
During the campaign, Mauer, Santagata, Vecchio and Lazzaroni relied on two instruments to map the lava tube in detail. These included the Pegasus Backpack, a wearable mapping solution that collects geometric data without a satellite ad synchronizes images collected by five cameras and two 3D imaging laser profilers, and the Leica BLK360 – the smallest and lightest imaging scanner on the market.
Join us on a trip through a volcanic wormhole! This 3D scan of the 8-km 'La Cueva de los Verdes' lava tube in Lanzarote, #Spain, was acquired during the @ESA_CAVES #Pangaea campaign.
Details: https://t.co/5csZlbzv4p pic.twitter.com/bVeZFCeyIP— European Space Agency (@esa) March 13, 2018
In less than three hours, the team managed to map all the contours of the lava tube. And while the results of the campaign continue to be analyzed, the team chose to use the data they obtained to produce a 3D visual of all the twists and turns of the lava tube. The scan that resulted covers a 1.3 km section of the cave system with an unprecedented resolution of a few centimeters.
Santagata and the Virtual Geography Agency also turned their 3D visual into a lovely video titled “Lave tube fly-through”, which beautifully illustrates the winding and organic nature of the lava tube system. This video was posted to the ESA’s twitter feed on Tuesday, March 13th (shown above). This video, like the scans that preceded it, represent a breakthrough in geological mapping and astronaut training.
While lava tubes have been mapped since the 1970s, a clear view of this subterranean passage has remained elusive until now. Beyond being the first, the scans the team conducted could also help scientists to study the origins of the cave system, its peculiar formations, and assist local institutions in protecting the subterranean environment. As intended, the scans could also assist future space exploration and colonization efforts.
For instance, the 8 km lava tube has both dry and water-filled sections. In the six-kilometer dry section, the lava tube has natural openings (jameos), that are aligned along the top of the cave pathway. These formations are very similar to “skylights” that have been observed on the Moon and Mars, which are holes in the surface that open into stable lava tubes.
Such structures are considered to be a good place for building outposts and colonies since they are naturally shielded from radiation and micrometeorites. Lava tubes also have a constant temperature, therefore offering protection against environmental extremes, and could provide access to underground sources of water ice. Some sections could also be sealed off and pressurized to create a colony.
As such, exploring such environments here on Earth is a good way to train astronauts to explore them on other bodies. As all astronauts know, mapping an environment is the first step in exploration, especially when you are looking for a place to establish a base camp. And in time, this information can be used to establish more permanent settlements, giving rise to eventual colonization.
If something called “Project METERON” sounds to you like a sinister project involving astronauts, robots, the International Space Station, and artificial intelligence, I don’t blame you. Because that’s what it is (except for the sinister part.) In fact, the Meteron Project (Multi-Purpose End-to-End Robotic Operation Network) is not sinister at all, but a friendly collaboration between the European Space Agency (ESA) and the German Aerospace Center (DLR.)
The idea behind the project is to place an artificially intelligent robot here on Earth under the direct control of an astronaut 400 km above the Earth, and to get the two to work together.
“Artificial intelligence allows the robot to perform many tasks independently, making us less susceptible to communication delays that would make continuous control more difficult at such a great distance.” – Neil Lii, DLR Project Manager.
On March 2nd, engineers at the DLR Institute of Robotics and Mechatronics set up the robot called Justin in a simulated Martian environment. Justin was given a simulated task to carry out, with as few instructions as necessary. The maintenance of solar panels was the chosen task, since they’re common on landers and rovers, and since Mars can get kind of dusty.
The first test of the METERON Project was done in August. But this latest test was more demanding for both the robot and the astronaut issuing the commands. The pair had worked together before, but since then, Justin was programmed with more abstract commands that the operator could choose from.
American astronaut Scott Tingle issued commands to Justin from a tablet aboard the ISS, and the same tablet also displayed what Justin was seeing. The human-robot team had practiced together before, but this test was designed to push the pair into more challenging tasks. Tingle had no advance knowledge of the tasks in the test, and he also had no advance knowledge of Justin’s new capabilities. On-board the ISS, Tingle quickly realized that the panels in the simulation down here were dusty. They were also not pointed in the optimal direction.
This was a new situation for Tingle and for Justin, and Tingle had to choose from a range of commands on the tablet. The team on the ground monitored his choices. The level of complexity meant that Justin couldn’t just perform the task and report it completed, it meant that Tingle and the robot also had to estimate how clean the panels were after being cleaned.
“Our team closely observed how the astronaut accomplished these tasks, without being aware of these problems in advance and without any knowledge of the robot’s new capabilities,” says DLR engineer Daniel Leidner.
The next test will take place in Summer 2018 and will push the system even further. Justin will have an even more complex task before him, in this case selecting a component on behalf of the astronaut and installing it on the solar panels. The German ESA astronaut Alexander Gerst will be the operator.
If the whole point of this is not immediately clear to you, think Mars exploration. We have rovers and landers working on the surface of Mars to study the planet in increasing detail. And one day, humans will visit the planet. But right now, we’re restricted to surface craft being controlled from Earth.
What METERON and other endeavours like it are doing, is developing robots that can do our work for us. But they’ll be smart robots that don’t need to be told every little thing. They are just given a task and they go about doing it. And the humans issuing the commands could be in orbit around Mars, rather than being exposed to all the risks on the surface.
“Artificial intelligence allows the robot to perform many tasks independently, making us less susceptible to communication delays that would make continuous control more difficult at such a great distance,” explained Neil Lii, DLR Project Manager. “And we also reduce the workload of the astronaut, who can transfer tasks to the robot.” To do this, however, astronauts and robots must cooperate seamlessly and also complement one another.
That’s why these tests are important. Getting the astronaut and the robot to perform well together is critical.
“This is a significant step closer to a manned planetary mission with robotic support,” says Alin Albu-Schäffer, head of the DLR Institute of Robotics and Mechatronics. It’s expensive and risky to maintain a human presence on the surface of Mars. Why risk human life to perform tasks like cleaning solar panels?
“The astronaut would therefore not be exposed to the risk of landing, and we could use more robotic assistants to build and maintain infrastructure, for example, with limited human resources.” In this scenario, the robot would no longer simply be the extended arm of the astronaut: “It would be more like a partner on the ground.”
The ESA’s Mars Express probe has been studying Mars and its Moons for many years. While there are several missions currently in orbit around Mars, Mars Express‘s near-polar elliptical orbit gives it some advantages over the others. For one, its orbital path takes it closer to Phobos than any other spacecraft, which allows it to periodically observe the moon from distances of around 150 km (93 mi).
Because of this, the probe is in an ideal position to study Mars’ moons and capture images of them. On occasion, this allows for some interesting photo opportunities. For example, in November of 2017, while taking pictures of Phobos and Deimos, the probe spotted Saturn in the background. This fortuitous event led to the creation of some beautiful images, which were put together to produce a video.
Since 2003, Mars Express has been studying Phobos and Deimos in the hopes of learning more about these mysterious objects. While it has learned much about their size, appearance and position, much remains unknown about their composition, how and where they formed, and what their surface conditions are like. To answer these questions, the probe has been conducting regular flybys of these moons and taking pictures of them.
The video that was recently released by the ESA combines 30 such images which show Phobos passing through the frame. In the background, Saturn is visible as a small ringed dot, despite being roughly 1 billion km away. The images that were used to create this video were taken by the probes High Resolution Stereo Camera on November 26th, 2016, while the probe was traveling at a speed of about 3 km/s.
This photobomb was not unexpected, since the Mars Express repeatedly uses background reference stars and other bodies in the Solar System to confirm positions of the moons in the sky. In so doing, the probe is able to calculate the position of Phobos and Deimos with an accuracy of up to a few kilometers. The probes ideal position for capturing detailed images has also helped scientists to learn more about the surface features and structure of the two moons.
For instance, the pictures taken during the probe’s close flybys of Phobos showed its bumpy, irregular and dimpled surface in detail.The moon’s largest impact crater – the Stickney Crater – is also visible in one of the frames. Measuring 9 km ( mi) in diameter, this crater accounts for a third of the moon’s diameter, making it one the largest impact craters relative to body size in the Solar System.
In another image, taken on January 15th, 2018, Deimos is visible as an irregular and partially shadowed body in the foreground, while the delicate rings of Saturn are just visible encircling the small dot in the background (see below). In addition, Mars Express also obtained images of Phobos set against a reference star on January 8th, 2018 (see above) and close-up images of Phobos’ pockmarked surface on September 12th, 2017.
In the future, the Mars Express probe is expected to reveal a great deal more about Mars’ system of moons. In addition to the enduring questions of their origins, formation and composition, there are also questions about where future missions could land in order to study the surface directly. In particular, Phobos has been considered for a possible landing and sample-return mission.
Because of its nearness to Mars and the fact that one side is always facing towards the planet, the moon could make for an ideal location for a permanent observation post. This post would allow for the long-term study of the Martian surface and atmosphere, could act as a communications relay for other spacecraft, and could even serve as a base for future missions to the surface.
If and when such a mission to Phobos becomes a reality, it is the Mars Express probe that will determine where the ideal landing site would be. In essence, by studying the Martian moons to learning more about them, Mars Express is helping to prepare future missions to the Red Planet.
Be sure to check out the time-lapse video of Phobos and Saturn, courtesy of the ESA:
Further Reading: ESA
It’s been a time of milestones for Mars rovers lately! Last month (on January 26th, 2018), NASA announced that the Curiosity rover had spent a total of 2,000 days on Mars, which works out to 5 years, 5 months and 21 days. This was especially impressive considering that the rover was only intended to function on the Martian surface for 687 days (a little under two years).
But when it comes to longevity, nothing has the Opportunity rover beat! Unlike Curiosity, which relied on a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) for power, the solar-powered Opportunity recently witnessed its five-thousandth sunrise on Mars. This means that the rover has remained in continuous operation for 5000 sols, which works out to 5137.46 Earth days.
This five-thousandth sunrise began on Friday, Feb. 16th, 2018 – roughly 14 Earth years (and 7.48 Martian years) after the rover first landed. From its position on the western rim of the Endeavour Crater, the sunrise appeared over the basin’s eastern rim, about 22 km (14 mi) away. This location, one-third of the way down “Perseverance Valley”, is more than 45 km (28 mi) from Opportunity’s original landing site.
This is especially impressive when you consider that the original science mission was only meant to last 90 sols (92.47 Earth days) and NASA did not expect the rover to survive its first Martian winter. And yet, the rover has not only survived all this time, it continues to send back scientific discoveries from the Red Planet. As John Callas, the Opportunity Project Manager at NASA’s Jet Propulsion Laboratory, explained in a NASA press release:
“Five thousand sols after the start of our 90-sol mission, this amazing rover is still showing us surprises on Mars… We’ve reached lots of milestones, and this is one more, but more important than the numbers are the exploration and the scientific discoveries.”
For instance, the rover has provided us with 225,000 images since its arrival, and revealed that ancient Mars was once home to extensive groundwater and surface water. Beginning in 2008, it began working its way across the Endeavour Crater in order to get a glimpse deeper into Mars’ past. By 2011, it had reached the crater’s edge and confirmed that mineral-rich water once flowed through the area.
At present, researchers are using Opportunity to investigate the processes that shaped Perseverance Valley, an area that descends down the slope of the western rim of Endeavour Crater. Here too, Opportunity has learned some fascinating things about the Red Planet. For instance, the rover has conducted observations of possible “rock stripes” in the valley, which could be indicative of its valley’s origin.
These stripes are of interest to scientists because of the way they resemble rock stripes that appear on mountain slopes here on Earth, which are the result of repeated cycles of freezing and thawing on wet soil. On Mauna Kea, for example, soil freezes every night, but is often dry due to the extreme elevation. This causes soils that have high concentrations of silt, sand and gravel to expand, pushing the larger particles up.
These particles then form stripes as they fall downhill, or are moved by wind or rainwater, and cause the ground to expand less in this space. This process repeats itself over and over, creating a pattern that leads to distinct stripes. As Opportunity observed, there are slopes within the Perseverance Valley where soil and gravel particles appear to have formed into rows that run parallel to the slope, alternating between rows that have more and less gravel.
In the case of the Perseverance Valley’s stripes, scientists are not sure how they formed, but think they could be the result of water, wind, downhill transport, other processes, or a combination thereof. Another theory posits that features like these could be the result of changes in Mars tilt (obliquity) which happen over the course of hundreds of thousands of years.
During these periods, Mars’ axial tilt increases to the point where water frozen at the poles will vaporize and become deposited as snow or frost nearer to the equator. As Ray Arvidson, the Opportunity Deputy Principal Investigator at Washington University, explahttps://www.nasa.gov/feature/jpl/long-lived-mars-rover-opportunity-keeps-finding-surprisesined:
“One possible explanation of these stripes is that they are relics from a time of greater obliquity when snow packs on the rim seasonally melted enough to moisten the soil, and then freeze-thaw cycles organized the small rocks into stripes. Gravitational downhill movement may be diffusing them so they don’t look as crisp as when they were fresh.”
Having the chance to investigate these features is therefore quite the treat for the Opportunity science team. “Perseverance Valley is a special place, like having a new mission again after all these years.” said Arvidson. “We already knew it was unlike any place any Mars rover has seen before, even if we don’t yet know how it formed, and now we’re seeing surfaces that look like stone stripes. It’s mysterious. It’s exciting. I think the set of observations we’ll get will enable us to understand it.”
Given the state of the Martian surface, it is a safe bet that wind is largely responsible for the rock stripes observed in Perseverance Valley. In this respect, they would be caused by sand blown uphill from the crater floor that sorts larger particles into rows parallel to the slope. As Robert Sullivan, an Opportunity science-team member of Cornell University, explained:
“Debris from relatively fresh impact craters is scattered over the surface of the area, complicating assessment of effects of wind. I don’t know what these stripes are, and I don’t think anyone else knows for sure what they are, so we’re entertaining multiple hypotheses and gathering more data to figure it out.”
Despite being in service for a little over 14 years, and suffering its share of setbacks, Opportunity is once again in a position to reveal things about Mars’ past and how it evolved to become what it is today. Never let it be said that an old rover can’t reveal new secrets! If there’s one thing Opportunity has proven during its long history of service on Mars, it is that the underdog can make some of the greatest contributions.
On February 6th, 2018, SpaceX successfully launched its Falcon Heavy rocket into orbit. This was a momentous occasion for the private aerospace company and represented a major breakthrough for spaceflight. Not only is the Falcon Heavy the most powerful rocket currently in service, it is also the first heavy launch vehicle that relies on reusable boosters (two of which were successfully retrieved after the launch).
Equally interesting was the rocket’s cargo, which consisted of Musk’s cherry-red Tesla Roadster with a spacesuit in the driver’s seat. According to Musk, this vehicle and its “pilot” (Starman), will eventually achieve a Hohmann Transfer Orbit with Mars and remain there for up to a billion years. However, according to a new study, there’s a small chance that the Roadster will collide with Venus or Earth instead in a few eons.
The study which raises this possibility recently appeared online under the title “The random walk of cars and their collision probabilities with planets.” The study was conducted by Hanno Rein, an assistant professor at the University of Toronto; Daniel Tamayo, a postdoctoral fellow with the Center for Planetary Sciences (CPS) and the Canadian Institute for Theoretical Astrophysics (CITA); and David Vokrouhlick of the Institute of Astronomy at Charles University in Prague.
As we indicated in a previous post, Musk’s original flight plan has the potential to place the Roadster into a stable orbit around Mars… after a fashion. According to Max Fagin, an aerospace engineer from Colorado and a space camp alumni, the Roadster will get close enough to Mars to establish an orbit by October of 2018. However, this orbit would not rule out close encounters with Earth over the course of the next few million years.
For the sake of their study, Rein and his colleagues considered how such close encounters might alter the Roadster’s orbit in that time. Using data from NASA’s HORIZONS interface to determine the initial positions of all Solar planets and the Roadster, the team calculated the likelihood of future close encounters between the vehicle and the terrestrial planets, and how likely a resulting collision would be.
As they indicated, the Roadster bears some similarities to Near-Earth Asteroids (NEAs) and ejecta from the Earth-Moon system. In short, NEAs permeate the inner Solar System, regularly crossing the orbits of terrestrial planets and experiencing close encounters with them (resulting in the occasional collision). In addition, ejecta from the Earth and Moon also experience close encounters with the terrestrial planets and collide with them.
However, the Tesla Roadster is unique in two key respects: For one, it originated from Earth rather than being pulled from the Asteroid Belt into the inner Solar System by strong resonances. Second, it had a higher ejection velocity when it left Earth, which tends to result in fewer impacts. “Given the peculiar initial conditions and even stranger object, it therefore remains an interesting question to probe its dynamics and eventual fate,” they claim.
Another challenge was how the probability of an impact will change drastically over time. While the chance of a collision can be ruled out in the short run (i.e. the next few years), the Roadster’s chaotic orbit is difficult to predict over the course of subsequent close encounters. As such, the team performed a statistical calculation to see how the orbit and velocity of the Roadster would change over time. As they state in their study:
“Given that the Tesla was launched from Earth, the two objects have intersecting orbits and repeatedly undergo close encounters. The bodies reach the same orbital longitude on their synodic timescale of ~2.8 yrs.”
They began by considering how the Roadster’s orbit would evolve over the course of its next 48 orbits, which would encompass the next 1000 years. They then expanded the analysis to consider long-term evolution, which encompassed 240 orbits over the course of the next 3.5 million years. What they found was that on a million-year timescale, the orbit of the Roadster remains in a region dominated by close encounters with Earth.
However, over time, their simulations show that the Roadster will experience changes in eccentricity due to resonant and secular effects. This will result in interactions more frequent interactions between the Roadster and Venus over time, and close encounters with Mars becoming possible. Over long enough timescales, the team even anticipates that interactions with Mercury’s orbit will be possible (though unlikely).
In the end, their simulations revealed that over the course of a million years and beyond, the probability of a collision with a terrestrial planet is unlikely, but not impossible. And while the odds are slim, they favor an eventual collision with Earth. Or as they put it:
“Although there were several close encounters with Mars in our simulations, none of them resulted in a physical collision. We find that there is a ~6% chance that the Tesla will collide with Earth and a ~2.5% chance that it will collide with Venus within the next 1 Myr. The collision rate goes down slightly with time. After 3 Myr the probability of a collision with Earth is ~11%. We observed only one collision with the Sun within 3 Myr.”
Given the Musk hoped that his Roadster would remain in orbit of Mars for one billion years, and that aliens might eventually find it, the prospect of it colliding with Earth or Venus is a bit of a letdown. Why bother sending such a unique payload into space if it’s just going to come back? Still, the odds that it will be drifting through space for millions of years remains a distinct possibility.
And if there are any worries that the Roadster will pose a threat to future missions or Earth itself, consider the message Starman was looking at during his ascent into space – Don’t Panic! Assuming humanity is even alive eons from now, the far greater danger will be that such an antique will burn up in our atmosphere. After millions of years, Starman is sure to be a big celebrity!
Further Reading: arXiv
In July of 2020, the Mars 2020 rover – the latest from NASA’s Mars Exploration Program – will begin its long journey to the Red Planet. Hot on the heels of the Opportunity and Curiosity rovers, the Mars 2020 rover will attempt to answer some of the most pressing questions we have about Mars. Foremost among these is whether or not the planet had habitable conditions in the past, and whether or not microbial life existed there.
To this end, the Mars 2020 rover will obtain drill samples of Martian rock and set them aside in a cache. Future crewed missions may retrieve these samples and bring them back to Earth for analysis. However, in a recent announcement, NASA indicated that a piece of a Martian meteor will accompany the Mars 2020 rover back to Mars, which will be used to calibrate the rover’s high-precious laser scanner.
This laser scanner is known as the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument. The laser’s resolution is capable of illuminating even the finest features in rock samples, which could include fossilized microorganisms. But in order to achieve this, the laser requires a calibration target so that the science team can fine-tune its settings.
Ordinarily, these calibration targets involve pieces of rock, metal or glass, samples that are the result of a complex geological history. However, when addressing the SHERLOC’s calibration needs, JPL scientists came up with a rather innovative idea. For billions of years, Mars has experienced impacts that have sent pieces of its surface into orbit. In some cases, those pieces came to Earth in the form of meteorites, some of which have been identified.
While these meteorites are rare and not identical to the geologically diverse samples the Mars 2020 rover will collect, they are well-suited for target practice. As Luther Beegle of JPL, the principle investigator for SHERLOC, said in a recent NASA press statement:
“We’re studying things on such a fine scale that slight misalignments, caused by changes in temperature or even the rover settling into sand, can require us to correct our aim. By studying how the instrument sees a fixed target, we can understand how it will see a piece of the Martian surface.”
In this respect, the Mars 2020 rover is in good company. For example, Curiosity’s used its Chemistry and Camera (ChemCham) instrument – which relies on laser-induced breakdown spectroscopy (LIBS) – to determine the elemental compositions of rock and soil samples it has obtained. Similarly, the Opportunity rover’s Miniature Thermal Emission Spectrometer (Mini-TES) allowed this rover to detect the composition of rocks from a distance.
However, SHERLOC is unique in that it will be the first instrument deployed to Mars that uses Raman and fluorescence spectroscopy. Raman spectroscopy consists of subjecting materials to light in the visible, near infrared, or near ultraviolet range and measuring how the photons respond. Based on how their energy levels shift up or down, scientists are able to determine the presence of certain elements.
Fluorescence spectroscopy relies on ultraviolet lasers to excite the electrons in carbon-based compounds, which causes chemicals that are known to form in the presence of life (i.e. biosignatures) to glow. SHERLOC will also photograph the rocks it studies, which will allow the science team to map the chemical signatures it finds across the surface of Mars.
For their purposes, the SHERLOC team needed a sample that would be solid enough to withstand the intense vibrations caused by launch and landing. They also needed one that contained the right chemicals to test SHERLOC’s sensitivity to biosignatures. With the help of the Johnson Space Center and the Natural History Museum in London, they ultimately decided on a sample from the Sayh al Uhaymir 008 meteorite (aka. SaU008).
This meteorite, which was found in Oman in 1999, was more rugged that other samples and could be sliced without the rest of the meteorite flaking. As a result, SaU008 will be the first Martian meteorite sample that helps scientists look for past signs of life on Mars. It will also be the first Martian meteorite to have a piece of itself returned to the surface of Mars – though technically not the first to be sent back.
That honor goes to Zagami, a meteorite retrieved in Nigeria in 1962, which had a piece of itself sent back to Mars aboard the Mars Global Surveyor (MGS) in 1999. That mission ended in 2007, so this chunk has been floating around in orbit of Mars ever since. In addition, the team behind Mars 2020‘s SuperCam instrument will also be adding a Martian meteorite for their own calibration tests.
Along with bits of SaU008, the Mars 2020 payload will include samples of advanced materials. Aside from also being used to calibrate SHERLOC, these materials will be tested to see how they hold up to Martian weather and radiation. If they prove to be tough enough to survive on the Martian surface, these materials could be used in the manufacture of space suits, gloves and helmets for future astronauts.
As Marc Fries, a SHERLOC co-investigator and curator of extraterrestrial materials at Johnson Space Center, put it:
“The SHERLOC instrument is a valuable opportunity to prepare for human spaceflight as well as to perform fundamental scientific investigations of the Martian surface. It gives us a convenient way to test material that will keep future astronauts safe when they get to Mars.”
With every robotic mission sent to Mars, NASA and other space agencies are working towards the day when astronauts’ boots will finally touch down on the Red Planet. When the first crewed mission to Mars are conducted (currenty scheduled for the 2030s), they will be following in the tracks of some truly intrepid robotic explorers!
Further Reading: NASA
After multiple delays, SpaceX recently announced that the inaugural flight of their Falcon Heavy rocket would take place this Tuesday, February 6th, 2018. This rocket, which is the heaviest launch vehicle in the SpaceX fleet (and the most powerful operational rocket in the world right now), is not only central to the company’s vision of reusable rockets, but also to Musk’s long-term vision of sending humans to Mars.
As a result, people all over the world have been tuning in to watch the coverage of the event, and eagerly waiting to see the rocket take off before its launch window closes at 04:00 pm (PST) this afternoon. In keeping with Musk’s habit of sending interesting payloads into space, the rocket will be carrying his cherry-red Tesla Roadster, with the goal of depositing it into a stable orbit around Mars.
According to previous statements made by Musk, the plan calls for the Falcon Heavy to launch the Roadster on a Hohmann Transfer trajectory, an orbital maneuver where a satellite or spacecraft is transferred from one circular orbit to another. After being placed in an elliptical orbit between Earth and Mars, the Roadster would be picked up by Mars’ gravity and remain in orbit around it for (according to Musk) up to a billion years!
To add to the peculiarity of the mission payload, Musk has also been clear that he wants the car to be playing “Space Oddity” – the famous song written and performed by the late and great David Bowie – as its launched into space. This classic song recently got a shot in the arm thanks to Canadian astronaut Chris Hadfield, who performed a rendition of the song while still serving as the commander of Expedition 35 aboard the International Space Station.
But unlike Hadfield’s more positive rendition of the song (which you can watch above), in which the astronaut (Major Tom) does NOT die, Musk’s Roadster will be belting out this tune in its original form. One can only assume that he’s not a particularly superstitious man, or just has a very quirky sense of humor. Considering that a previous payload consisted of a wheel of cheese, I think we know the answer!
Musk confirmed that the launch would take place at 0:130 pm EST (10:30 am PST) in a tweet he posted yesterday, where he stated:
All systems remain green for launch at 1:30pm EST tomorrow
— Elon Musk (@elonmusk) February 5, 2018
This was followed by an additional tweet posted at 07:59 am PST, which indicated that the launch was still on. However, Musk announced that there would be a minor delay at 09:02 am PST, which was apparently weather-related:
“About 2.5 hours to T-0 for Falcon Heavy. Watch sim for highlight reel of what we hope happens. Car actually takes 6 months to cover 200M+ miles to Mars”
“Upper atmosphere winds currently 20% above max allowable load. Holding for an hour to allow winds to diminish.
#FalconHeavy“
In addition, changes were seen in the countdown clocks run by the US Air Force’s Eastern Range operations. This pushed the launch from its original time of 01:30 pm to 03:19 pm EST (12:19 am PST), and then led to the count being placed on hold. By 10:52 am PST this morning, the launch clock resumed and Musk indicated that the takeoff would commence at 3:45 pm EST (12:45 PST).
This was followed by the SpaceX ground crew commencing procedures to fuel the rocket at about 11:22 am PST.
Launch auto-sequence initiated (aka the holy mouse-click) for 3:45 liftoff #FalconHeavy
— Elon Musk (@elonmusk) February 6, 2018
Naturally, there has been plenty of speculation about the possible outcome of the mission. Max Fagin, an aerospace engineer from Colorado and a space camp alumni, is one such person. In a video he uploaded to his Youtube channel yesterday (Feb. 5th, 2018), he clarified what the proposed launch entails and offered his thoughts on what will likely happen to the Roadster once its sent into space.
Addressing Musk’s stated goal of a Hohmann Transfer that would put the roadster into Mars’ orbit, he indicated that Musk must have been oversimplifying because there’s no reason to launch a spacecraft on such a trajectory right now. This is due to the fact that this maneuver only makes sense when Earth and Mars are at the closest points in their orbits to each other – aka. when Mars is at opposition.
This is not the case at present, and won’t be again until April-May of this year. At that point, Earth and Mars will be the closest they have been to each other since the year 2000, and will not be in such a perfect opposition again until 2033. As a result, says Fagin, a “true Hohmann Transfer launched from Earth to Mars right now would take the Roadster no closer than 90 million km from Mars – 0.6 times the distance from Earth to the Sun.”
Having said all that, here is what Fagin thinks is actually going to happen:
“Given how light the Roadster is, and given how powerful the Falcon Heavy is, I suspect Falcon heavy is going to impart a little extra delta-v to the Roadster, beyond what would be required for a minimum-energy Hohmann Transfer. This would allow the Roadster to get as close to Mars as SpaceX wanted sometime in October of 2018.”
According to Fagin’s analysis, the Roadster would still not be able to remain in the same orbit of Mars for a billion years, which was Musk’s stated goal. But it would achieve a more stable orbit than a basic Hohmann Transfer would accomplish. In that scenario, the orbit would be perturbed by close encounters with Earth, and the Roadster might eventually come back to Earth.
In other words, the plan may be more complicated than originally stated, but could be largely successful all the same. Come what may, there is no shortage of people who want to see this rocket successfully take off! After all, it’s not only SpaceX’s future that is riding on the outcome of this launch, but perhaps even the future of space exploration itself. Cheaper costs and restored launch capability, that’s what it’s all about!
Barring any further delays, which will push the launch back until tomorrow, the launch will be taking place in T-minus 20 minutes (as of the penning of this article)! In the meantime, be sure to check out SpaceX’s live coverage of the event, which begins today (Tuesday, Feb. 6th) at 12:45 pm (GMT-8):
Further Reading: SpaceX webcast, SpaceX, Twitter (Elon Musk), Orlando Sentinel