Scientists have discovered the first evidence of water vapor on Ganymede, Jupiter's largest moon. They used new and archival datasets from the Hubble Space Telescope to find the vapor, which forms when ice on the surface sublimates and turns from solid to gas.
A team led by Lorenz Roth of the KTH Royal Institute of Technology in Stockholm, Sweden examined data captured by Hubble's Cosmic Origins Spectrograph in 2018 and images the Space Telescope Imaging Spectrograph obtained between 1998 and 2010. Ultraviolet images captured by the STIS in 1998 showed “colorful ribbons of electrified gas called auroral bands,” according to NASA (which launched Hubble as a joint project with the European Space Agency).
Researchers previously believed that atomic oxygen may have caused discrepancies between UV images that were captured over time. However, using data from the Cosmic Origins Spectrograph, Roth's team found that there was barely any atomic oxygen in the moon's atmosphere. As such, there had to be another reason for the discrepancies.
The temperature at Ganymede's equator may become warm enough for surface ice to release some water molecules. When they re-examined the relative distribution of the aurora in the UV images, Roth's team found that differences between them match up with where water would be expected in the moon's atmosphere.
Previous research indicated that Ganymede may hold more water than in all of our oceans. The moon's ocean is believed to be around 100 miles below the surface, so the vapor isn't from there. Water on the surface is frozen due to the moon’s temperatures.
The finding arrived ahead of the ESA's wonderfully named upcoming mission, JUICE, or JUpiter ICy moons Explorer. The mission should launch in 2022 and arrive at Jupiter in 2029. It will then spend at least three years examining the planet and three of its largest moons. JUICE will pay special attention to Ganymede, both as a planetary body and possible habitat.
"Our results can provide the JUICE instrument teams with valuable information that may be used to refine their observation plans to optimize the use of the spacecraft," Roth said in a statement.
NASA's Juno mission has also been studying Ganymede and Jupiter's environment (aka the Jovian system) since 2016. The agency says examining the Jovian system and understanding its history "will provide us with a better understanding of how gas giant planets and their satellites form and evolve. In addition, new insights will hopefully be found on the habitability of Jupiter-like exoplanetary systems."
A SpaceX Falcon Heavy rocket will be launching NASA's long-awaited mission to Europa, Jupiter's icy moon that may have the conditions to support life. The agency has been planning to send a probe to the Jovian moon for years and finalized its plans in 2019. In its announcement, NASA said the Europa Clipper spacecraft is scheduled to launch in October 2024 on top of a Falcon Heavy rocket from Kennedy Space Center's Launch Complex 39A. It has also revealed that the contract will cost the agency approximately $178 million — a bargain, compared to what it would've cost to launch the mission on top of NASA's Space Launch System rocket.
As Ars Technica notes, Congress originally urged NASA to use the SLS to launch the Europa Clipper. At the time, though, the White House estimated a single SLS launch to cost a whopping $2 billion. Far from ideal, especially since the SLS would need gravity assist from Venus and travel farther to be able to reach its goal, whereas the Falcon Heavy wouldn't. In addition, NASA told Ars that the SLS would need $1 billion worth of additional modifications to be able to complete the mission.
If Europa Clipper launches in October 2024 as planned, it will reach Jupiter's orbit in April 2030. The probe will then investigate whether the icy moon truly has conditions suitable for life. It'll capture "high-resolution images of Europa's surface, determine its composition, look for signs of recent or ongoing geological activity, measure the thickness of the moon's icy shell, search for subsurface lakes, and determine the depth and salinity of Europa's ocean."
While scientists have found plenty of exoplanets over the years, they've yet to spot to moons orbiting those worlds outside our solar system. Now, a group of astronomers has discovered (PDF) what's believed to be a region with exomoons-in-the-making for the first time. Myriam Benisty and team from the University of Grenoble found the disk of dust — the moon-forming region — around a young exoplanet in a star system dubbed PDS 70 located 370 light years from Earth.
The team found the first protoplanet (PDS 70b) in the system back in 2018 using European Southern Observatory's Very Large Telescope in Chile. A year later, they found another young gas giant (PDS 70c) using the same equipment. The astronomers believe based on the data they have that the star system is only 10 million years old and that both gas giants are several times bigger than Jupiter. To know more about the system, they focused all other possible instruments on it, including the Atacama Large Millimeter/submillimeter Array. ALMA is made up of 66 short-wavelength radio dishes, and its observations made it possible to spot the dust around PDS 70c.
The disk of dust spans a distance slightly wider than that between Earth and the Sun, and there's enough mass in there for three moons the same size as ours. Benisty says the moons may have already formed, but there's no conclusive proof yet because they can't be seen with ALMA. According to Science, the Extremely Large Telescope, which will be the world's largest optical telescope when it's built, may have the power to see if the moons have already formed around the protoplanet. The telescope is still under construction, though, and scientific operations won't start until 2027 at the earliest.
NASA's InSight lander arrived on Mars in 2018 to learn about its interior by monitoring "marsquakes," and now the project is starting to really pay off. NASA has announced that researchers have mapped the red planet's interior and discovered some big surprises and major differences with Earth.
The map is the first ever of the interior of another planet. Compared to Earth, Mars has a thicker crust, thinner mantle layer and a bigger, less dense and more liquid core than expected. That in turn suggests that Mars may have formed millions of years before our planet, when the sun itself was still not fully formed.
"It gives us our first sample of the inside of another rocky planet like Earth, built out of the same materials but very, very different," University of Cambridge seismologist Sanne Cottaar (who wasn't involved in the project) told the Wall Street Journal. “It is impressive.”
Constructing a map from the limited data provided by InSight was no easy feat. The probe only recorded quakes from one location and has just a single seismometer, for one thing. And Mars — while seismically active — didn't have any quakes larger than around 4 on the Richter scale.
Science
Still, taking that data, along with planet's magnetism and orbital wobbles, scientists were able to create a detailed map. The planet's innermost core was found to have a diameter of around 2,275 miles, larger than previously thought. Given the mass of the planet as a whole, that implies that the iron/nickel core likely contains lighter elements like sulfur, oxygen and carbon.
The crust, meanwhile, was found to be very old. It was also thicker in Mars' southern highlands and thinner in the northern lowlands, which may have hosted oceans long ago. On average, it's between 15 and 45 miles thick and split into several layers of volcanic rock.
The mantle between the crust and core extends roughly 970 miles below the surface. It's thinner than Earth's and has a different composition which suggests the two planets arose from different materials when they formed. This “might be the simple explanation why we don’t see plate tectonics on Mars,” ETH Zurich geophysicist and study co-author Amir Khan told the New York Times.
The results has given scientists new insight into not just the inside of Mars, but how rocky planets form in general. That will help them develop new theories about planet formation that could become particularly valuable in the near future, when new instruments like the James Webb Space Telescope will allow astronomers to scan exoplanets around the galaxy. NASA will reveal more about its findings in a live event later today.
NASA's Curiosity rover might be sitting near a wealth of information that might hint at signs of life on Mars. New Scientist and Space.com note that Caltech researchers have identified six locations for methane "burps" (that is, emissions blips) on the planet, including one just a few dozen miles west southwest from Curiosity. Ideally, the rover could investigate the emissions and determine their true nature.
Curiosity has detected the methane spurts six times since landing on Mars in 2012, but scientists haven't had success locating their sources until now. Europe's Trace Gas Orbiter has also failed to spot methane at atmospheric levels. The Caltech team narrowed down the on-the-ground sources by modelling methane particles as packets and tracing their routes based on historical wind velocity.
The research hasn't yet been peer-reviewed, so we'd take it with a grain of caution. It's also entirely possible that the gas has non-organic origins. Even if that's the case, though, the burps could be tied to geological activity linked to liquid water. Early Mars reportedly held massive amounts of water — even if there's no active water at these sources, a close-up study could help illustrate Mars' history.
On May 5, 1961, Commander Alan Shepard piloted his Mercury Freedom 7 spacecraft to a soaring height of 116 miles above the planet's surface to become the first American to reach Earth's orbit. This past Sunday, Sir Richard Branson was escorted to an altitude of 50 miles aboard Virgin Galactic's SpaceShipTwo Unity. Somehow, these men are now both considered astronauts.
The discrepancy here lies in the fact that since the Space Era began, the world's exo-planetary powers have never really gotten around to formalizing where the Earth's atmosphere ends and where "space" — loosely defined as it is — begins. Even within the US federal bureaucracy, different agencies use different standards. What NASA mission control considers the edge of space is actually 26 miles farther out than where the NOAA and US Air Force demark the atmospheric boundary. So the next time you find yourself hurtling through the Mesosphere, keep a close eye on your altimeter if you want to earn the coveted Astronaut Badge.
After tragedy, multiple delays and plenty of rivalry, Virgin Galactic has completed its first fully crewed spaceflight. The Unity 22 mission saw founder Richard Branson join Beth Moses, Colin Bennett and Sirisha Bandla aboard SpaceShipTwo as they tested the spacecraft and conducted experiments. Branson , as you might guess, was there both for the prestige and to gauge the "private astronaut experience."
The flight has included some share of controversy. Blue Origin, whose first crewed spaceflight is just days away, has trash-talked Virgin by arguing that SpaceShipTwo wouldn't really enter space — the craft reached an altitude of 'just' 53.4 miles during Unity 22 where the Kármán line (the formal demarcation for space) is 62 miles. If you're focused on technicalities, Jeff Bezos will be the first corporate magnate to cross that symbolic barrier.
Whether or not you agree, the flight is an important achievement for Virgin. It's the first full test of SpaceShipTwo, and paves the way for commercial spaceflights if and when they start in 2022. Branson's outfit has been generating money with test flights, but it won't fulfill its business ambitions until tourists can finally use their tickets and get a taste of space.
The concept of space travel was so new to us that when President Kennedy issued his famous moonshot speech, not even NASA's top scientists were completely sure we could actually land on the lunar surface. Some thought any craft that set down there would simply sink into the moon's regolith like it was a massive, airless pit of quicksand! In his latest book, Across the Airless Wilds: The Lunar Rover and the Triumph of the Final Moon Landings, journalist and former Fulbright fellow, Earl Swift, examines the oft ignored Apollo 15, 16, and 17 missions, our last trips to the Moon's surface (at least until the Artemis project takes place). In the excerpt below, Swift takes the reader on a tour of the JPL's hyper-rigorous, tread-shredding lunar test course and the battle for rover supremacy waged there between GM and Bendix.
All through 1962 and into 1963, both GM and Bendix kept an eye on the Surveyor program. Sure enough, come summer, the Jet Propulsion Laboratory laid out its requirements for a hundred-pound, remote-controlled rover that it wanted to stash aboard the landers. The vehicle would explore the lurrain up to a mile from the Surveyors, while its drivers back on Earth steered it with television eyes. The laboratory alerted companies planning to bid on the phase 1 design study—the normal first stage of any new hardware program—that they’d be expected to supply engineering models of their concepts. Proposals were due in seven weeks.
The short deadline weeded out the dilettantes. In October the two companies left standing—GM and Bendix—started work under contract. GM was ready with its six-wheeled design. Its Surveyor lunar roving vehicle was six feet long on eighteen-inch wheels and weighed ninety pounds—half the size and half again as heavy as its test bed, with a sure-footedness that was no less jaw-dropping. On Pavlics’s “lunarium” of rocks, craters, and slopes outside the Santa Barbara lab, it climbed forty-five-degree inclines, leapt twenty-inch crevasses, and bent its way up and over thirty-inch steps.
Bekker and Pavlics had been working on the idea for more than three years by then. Their main advancement this time: the wheels. Again, they were made of wire, but it was knotted into a wide mesh that resembled chain-link, and shaped into fat doughnuts. Like the team’s earlier wire tires, they deflected when they hit an obstacle and absorbed some of the bumps of cross-country travel. They worked with or without a fabric covering.
“We had a big program to try to come up with the wire material that would survive the vacuum environment on the moon,” John Calandro recalled. “Frank had devised a testing device that created the vacuum environment we needed.”
When fully geared up for a mission, the rover would be an electronic wonder, with subsystems supplied by RCA Astro-Electronics and by AC Electronics, a GM division in Milwaukee: it would have a stereo TV imaging rig, sophisticated navigation and control, and silver-zinc batteries recharged by solar panel. But Santa Barbara’s part of the job, the vehicle itself, was a study in doing more with less. The hardware was constantly “assessed to see if something simpler might be able to do the same job,” designer Norman J. James would remember. “‘The part that’s left off never breaks’ was an often-repeated phrase.”
Bendix took a radically different approach. Its SLRV was a squarish, two-part, articulated robot, with curving, shock-absorbing legs at its corners that ended in small caterpillar track assemblies. The tracks pitched independently to follow uneven ground. Its handlers steered it with commands to slow, speed up, or reverse the tracks on one side or the other, and the pivot linking the two halves did the rest. On the moon, it would be powered by a radioisotope thermal generator—a small nuclear device—hanging off the back, and bristle with scientific instruments and antennas. It weighed one hundred pounds.
Side by side with the GM model, the Bendix machine looked bulky and awkward, and those tiny tracks didn’t seem much of a match for Pavlics’s nearly spherical wire wheels. But Bendix was bullish on its design right up to the day in May 1964 when a panel from the U.S. Geological Survey, Caltech, and NASA took the two models to a volcanic field north of Flagstaff, Arizona, and turned them loose on the rugged Bonito Lava Flow. “We had one little section where they could really get into some pretty rough stuff,” the Geological Survey’s Jack McCauley recalled years later. “The GM vehicle was perfect. It got from point A to point B without any mishaps or turning over.
“The poor Bendix vehicle had tanklike treads that were made of some kind of rubber-type thing,” McCauley said. “The vehicle just started shredding the treads. In fact, when they finished halfway down the course, it had no treads left. So, the GM thing obviously got our blessing.”
General Motors had scored a decisive victory. Unfortunately, it didn’t add up to a rover on the moon. The “Rover Boys,” as that panel of testers came to be known, were mightily impressed with the six-wheeler, but its capabilities didn’t square with the Jet Propulsion Laboratory’s requirements: namely, to “go around and take pictures every ten meters, and also to use a penetrometer to see what the strength of the lunar soil was—and to do it in a preordained manner,” McCauley said. “Basically, just do a grid survey.” Bendix had produced too little rover for the mission; GM had produced too much. The Rover Boys reluctantly reported that neither rover matched the Surveyor program’s stated needs, and that was among the reasons that NASA scrubbed the rover component not long after.
By that time, JPL’s Ranger program had finally given NASA its first close looks at the moon. By design, they were fleeting glimpses: Ranger probes crashed into the lunar surface while taking high-resolution photos right up to the moment of impact. Conceived in 1959, the program had, at times, seemed another exercise in frustration. After Rangers 1 and 2 made two development test voyages in 1961, along came Rangers 3 through 6, all of which were busts. It wasn’t until July 1964, and Ranger 7, that the program literally hit pay dirt. As the spacecraft fell toward the moon, its cameras kicked on, and, for some seventeen minutes, it took and transmitted photographs of the approaching surface—4,316 images in all, some of them at a resolution hundreds of times greater than the best taken from Earth. The photos didn’t put to rest the fears inspired by Thomas Gold’s writings and lectures, but they did establish that the maria were smooth enough for a landing.
On July 11th, Virgin Galactic founder Richard Branson, could fly to space aboard the SpaceShipTwo to assess the company's private astronaut experience. If you ask rival company Blue Origin, though, Branson won't really be reaching space when he does. In a couple of tweets, the Jeff Bezos-owned space corporation compared what its own New Shepard suborbital vehicle can do with SpaceShipTwo's capabilities. First in the list? The company says New Shepard was designed to fly above the Kármán line, whereas its competitor's vehicle was not.
The Kármán line is the boundary between the Earth's atmosphere and outer space as set by the Fédération Aéronautique Internationale. It's defined as 100 kilometers or 62 miles above sea level, and according to Blue Origin, it's what "96 percent of the world's population" recognizes as the beginning of outer space. Blue Origin plans to offer customers 10 minutes of flight with an altitude that reaches the Kármán line. Meanwhile, Virgin Galactic's website says its flights will soar at "nearly" 300,000 feet (57 miles) in altitude. That doesn't quite reach the Kármán line, though that's still higher than what NASA and the US government defines as the beginning of space (50 miles above sea level).
Only 4% of the world recognizes a lower limit of 80 km or 50 miles as the beginning of space. New Shepard flies above both boundaries. One of the many benefits of flying with Blue Origin. pic.twitter.com/4EAzMfCmYT
Aside from comparing their vehicles' maximum altitudes, Blue Origin also made it a point to mention that the New Shepard has the largest windows in space. Also, the New Shepard is a rocket, but SpaceShipTwo, according to Blue Origin, is just a high-altitude plane. The company published the comparison after Virgin Galactic scheduled Branson's trip to space before Jeff Bezos' — the multi-billionaire and his brother will join Blue Origin's first suborbital tourist flight that's scheduled for a July 20th launch.
CRISPR gene editing is no longer confined to Earth. Astronaut Christina Koch and scientists have successfully demonstrated CRISPR-Cas9 in space for the first time, using it as part of a new technique to damage DNA and study how it repairs in microgravity. "Technical and safety concerns" had prevented earlier studies like this, according to the researchers.
The experiment produced a particularly damaging double-strand DNA break in a yeast cell culture aboard the International Space Station. Koch completed the test well before this (most of the supplies reached the ISS in May 2019), but the findings weren't available until this past week.
The new approach clears the way for other research around DNA repair in space. With enough work, the scientists hope they can replicate the genetic damage from ionizing radiation, not to mention other effects from long-term spaceflight. That, in turn, could help NASA and other agencies develop technology that shields astronauts and makes deep space exploration practical. There's a chance CRISPR might play an important role in getting humans to Mars and beyond.
