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and supplies are the second-largest expense for overall research capability will probably in Poughkeepsie, New York, who studies his research, after paying wages. Lapen says decline under the tariffs. science and technology development in China, that his costs are likely to increase because the But other researchers aren’t worried. says that the tariffs would not have a significant US tariff list includes equipment or parts his Roberto Refinetti, a biopsychologist who effect on research projects and experiments in team needs, such as electrical motors that drive studies biological clocks at Boise State Uni- China. She says that is because some univer- centrifuges. versity in Idaho, uses some small Chinese- sities have large enough budgets to absorb Priscilla Cushman, a dark-matter physicist manufactured equipment for his work, such increased costs. Researchers could also share at the University of Minnesota in Minneapo- as infrared motion detectors for monitoring more equipment than they do now, or use lis, says that research deans at US universities rodents. He doesn’t think that the tariffs on goods made domestically and from countries should be scrutinizing the list to see whether Chinese goods will significantly increase the other than the United States. the taxes will affect their facilities. cost of his research, because he purchases that Brian Xu, a toxicologist for the scientific type of equipment infrequently. consulting firm ACTA in Washington DC, SCIENCE SQUEEZE The White House and the Office of the which works with businesses in China, agrees The tariffs could also cause havoc for large- United States Trade Representative did not that China’s proposal to place tariffs on US scale experiments, such as the ADMX respond to Nature’s request for comment on chemicals and scientific equipment is unlikely dark-matter detector at the University of Wash- researchers’ concerns. to have a major effect on Chinese research. ington in Seattle, which is under construction. In China, the tariff dispute could increase the He notes that scientists there import only a The project’s lead scientist, physicist Leslie cost of standard reagents used in laboratory and small amount of US-made chemicals, and Rosenberg, is worried that the equipment his medical devices that scientists import from the that infrequently replaced scientific equip- team needs to build experiments — such as United States. Ruibang Luo, a bioinformatician ment from other countries, such as Japan and tools for power generation and distribution, at the University of Hong Kong who collabo- Germany, is of comparable quality and cost. and machinery that has Chinese electrical com- rates with researchers on the mainland, says But the latest round of tariffs might not ponents — could be subject to the latest tariffs. that if the Chinese government interprets some be the last. On 18 June, Trump threatened to “Anyone can see the tariff list, but an official tariff items literally, the taxes could apply to a impose additional tariffs on Chinese goods must determine whether any particular pro- broad range of US-made reagents and research if the country does not rescind its tariffs and curement falls under the tariff,” he says. devices, including some DNA sequencers. create a more balanced trade relationship with Rosenberg thinks that the United States’ But Yu Zhou, a researcher at Vassar College the United States. ■

SPACE Japanese mission reaches unexplored asteroid Ryugu Hayabusa-2 will release four landing probes before touching down to collect samples.

BY DAVIDE CASTELVECCHI “From a distance, Ryugu initially appeared a fly-by of a C-type asteroid from a distance round, then gradually turned into a square of more than 1,000 kilometres. Hayabusa-2 is fter travelling for three and a half years, before becoming a beautiful shape simi- the only spacecraft to have come this close to a the Japanese spacecraft Hayabusa-2 lar to fluorite, known as the ‘firefly stone’ in C-type asteroid, says Lucy McFadden, a plan- this week makes its final approach Japanese,” project manager Yuichi Tsuda said etary scientist at NASA’s Goddard Space Flight Ato the asteroid Ryugu. The probe will release in a 25 June statement. Center in Greenbelt, Maryland. landers on the space rock’s surface later this Launched in December 2014, the probe is a “We don’t know much about C-type aster- year and bring a precious sample back to ter- follow-up to — and near-clone of — Hayabusa, oids,” says McFadden. But they are expected to restrial labs in 2020. It is already giving plan- which explored the asteroid Itokawa starting have a composition similar to that of the early etary scientists their closest-ever view of a in 2005. Hayabusa Solar System. In particular, Hayabusa-2 will mysterious kind of asteroid. was the first mission “Ryugu initially determine whether the darkness of Ryugu’s The Japan Aerospace Exploration Agency to return an aster- appeared round, surface is due to it being rich in carbon — as is (JAXA) last week released grainy pictures oid sample to Earth. before becoming often assumed — or to small, metallic particles from a distance of around 300 kilometres away, Ryugu is about 1 a beautiful such as magnetite. revealing that Ryugu — an asteroid of a com- kilometre across — shape similar to Chemical and isotopic analyses of the rock mon but little-studied type — looks similar to around 3 times wider fluorite.” — to be done in space by Hayabusa-2’s landers a spinning top. than Itokawa but and then in terrestrial labs — could help to This week, a much more detailed picture, one-quarter the size of the comet 67P/Churyu- explain the origins of Earth and, particularly, from 40 kilometres away, showed a surface mov–Gerasimenko, which the European Space its water. Many researchers think that Earth’s strewn with large boulders. Hayabusa-2 will Agency’s Rosetta probe visited between 2014 oceans formed from a bombardment of water- continue to inch towards the asteroid until it is and 2016. rich asteroids or comets. about 10 kilometres away, which JAXA expects Ryugu is a ‘C-type’ asteroid, which has a Among the first measurements Hayabusa-2 will happen around 27 June. Ryugu’s orbit cuts darker surface than does Itokawa. In 1997, a made was one of Ryugu’s rotational period, or between those of Earth and Mars. NASA mission called NEAR Shoemaker made time it takes to make one turn on its own

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the asteroid, and the three other small probes carried by the mothership. JAXA “We will use the information we get from the mother spacecraft to do landing-site selection,” says MASCOT payload manager Stephan Ulamec of the German Aerospace Center in Cologne. Ulamec was also project manager for Philae, a probe that Rosetta released onto the surface of 67P/Churyumov–Gerasimenko. That approach took several hours because Rosetta was orbiting the comet and Philae had to spiral down to its surface. Hayabusa-2 will simply hover over Ryugu — using its own gentle ion engines to counteract the asteroid’s gravitational attraction — and release MASCOT straight down. Some time in October, the lander will make a soft touch- down. After MASCOT settles on the surface, an internal mechanism will straighten the lander up so it can use its on-board instruments and communicate with Hayabusa-2. MASCOT carries no solar panels and its batteries are expected to last only a few hours. The team will meet in Toulouse, France, in An artist’s impression of Hayabusa-2. mid-August to make the final selection for the landing site of MASCOT and its companions. axis, which is about 7.5 hours. This is good is to pinpoint its own position using laser rang- Meanwhile, Hayabusa-2 will make its own, news, because a much faster rotation could have ing so that it can manoeuvre accordingly. “We brief soft landings to collect samples of the made it harder to approach the surface, says want to know the exact distance of the space- asteroid’s surface. Then, in late 2019, it will mission manager Makoto Yoshikawa of JAXA’s craft to the asteroid,” Yoshikawa says. Also head back to Earth, a journey expected to last Institute of Space and Astronautical Science in crucial is to map the asteroid surface using its a year. Compared to the more daring manoeu- Sagamihara. But its shape was surprising, he on-board camera and infrared spectrometer. vres to reach the asteroid’s surface, the current says, because it has a bulge around the equator, Temperature variations will hint at the com- part of the mission is relatively low risk, says something that is usually associated with much position of the surface. All of these data will Yoshikawa. But as the craft approaches Ryugu, faster-spinning objects, Yoshikawa adds. be crucial for deciding where to release MAS- his team has already kicked into high gear, he Hayabusa-2’s most important task right now COT, the shoebox-sized lander that will probe adds: “I do not have much time for sleep.” ■

CLIMATE CHANGE Methane leaks from US gas fields dwarf official estimates Latest study suggests that emissions could be coming from faulty equipment.

BY GIORGIA GUGLIELMI estimates. That research prompted the chemist at the Environmental Defense Fund, government to develop regulations that would a non-profit group in Austin, Texas. ethane leaks from the US oil and restrict methane emissions from oil and gas Methane warms the planet 80 times as much gas industry are 60% greater than production — rules that US President Donald as carbon dioxide does over the first 20 years official estimates, according to an Trump is now attempting to roll back. after it is released. And atmospheric methane Manalysis of previously reported data and new The latest study shows that the US oil and contributes to about 25% of global warming, airborne measurements. gas supply chain emits about 13 million tonnes Alvarez says. “That’s a significant amount.” Because methane is a potent greenhouse of methane, the main component of natural If left unchecked, he says, methane emissions gas, scientists say that the unaccounted-for gas, every year. That’s much higher than the from the oil and gas industry could erode the emissions could have significant impacts on US Environmental Protection Agency (EPA) potential climate benefits of using natural gas, the climate. estimate of about 8 million tonnes. which releases much less CO2 and other toxic The analysis1, published on 21 June in This discrepancy probably stems from the pollutants than coal does when it is burned. Science, is one of the most comprehensive looks fact that the EPA’s emissions surveys miss The latest study comes one year after the yet at methane output from US oil and gas pro- potential sources of methane leaks, such as EPA announced a delay of the rule that would duction, and reinforces previous studies that faulty equipment at oil and gas facilities, says restrict methane emissions produced by suggested emissions outpaced government study leader Ramón Alvarez, an atmospheric oil and gas drilling operations. The policy,

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