This will be an important year for pioneers developing electric vertical take-off and landing (eVTOL) aircraft (垂直起降飞机), popularly known as flying taxis. Several firms are hoping their craft can obtain the necessary certification in 2023 to start commercial production, getting ready for the first passenger services.

Air taxis generally carry fewer than half a dozen passengers. They land and take off vertically using multiple small rotors (旋翼). With clever software controlling the rotors, they are easier to fly and readily capable of autonomous flight. The plentiful number of rotors also helps with safety, as the aircraft can continue to fly if one or more fail.

Some designs use an extra rotor or two at the back to push the aircraft along during flight. Others, like that produced by Joby Aviation, have rotors like a set of small wings providing lift, making more efficient use of the aircraft's battery and increasing range.

After thinking hard about how to certify(授予专业合格证) these flying machines, regulators(监管者) have been working with developers on safety standards. This is a multi-stage process. Besides obtaining “type” approval, which shows the airworthiness of a new type of aircraft, factories must be certified before production can begin in volume. And an airline-style licence is required if paying passengers are to be carried. Companies are working hard to get these approvals. Piloted operations are expected to be approved before autonomous flights.

In Germany, Volocopter will be flight-testing a family of eVTOLs. The firm is hoping its smallest, the two-seater VoloCity, can be certified in time for the 2024 Olympics in Paris, where the plan is to operate trips between airports and the athletes' village. Other air-taxi firms also hope to provide services in Paris, or at the World Expo, which takes place in Japan in 2025.

A long-term dream for 3D bioprinting is that people on active waiting lists for organ donations might one day have the option of getting a bio-printed organ. Although the ability to produce a functional heart or kidney this way likely lies years in the future, realistic near-term goals include bioprinting simpler structures. Living tissues printed outside the body, however, would still require implantation operation, which often involves large incisions （切 口）that increase the risk of infection and lengthen recovery time.

Scientists in Tsinghua University are working on a way to print cells directly inside the body. The idea would be to use existing minimally invasive （微创）operation techniques to insert 3D printing tools into patients and then lay down new tissues.

Much of the previous research has focused on treatments of skin and other tissues in the outer part of the body, because the necessary equipment is normally too large to access :he digestive tract (消化道）and other centrally located organs. Scientists in China wanted to develop a mini bioprinting robot that could enter the human body with relative case, so that they can use the technology for conditions like stomach ulcer （胃溃疡）.

The resulting micro robot is just 30 millimeters wide—less than half the width of a credit card — and can fold to a length of 43 millimeters. Once inside a patient's body, it unfolds to become 59 millimeters long and can start bioprinting. The team has constructed clever mechanisms that make the system compact when entering the body yet extend to provide a large working area once past the tight entry. In their experiments， the researchers in China fitted the micro robot onto a long tube that can be inserted through bodily openings and successfully snaked it through a curved pipe into a transparent plastic model of a stomach.

A ship has used autonomous (自主的) sailing technology to complete a trip across world oceans for the first time. The Mayflower Autonomous Ship is a completely autonomous ocean research ship powered by artificial intelligence (AI) technology.

The Mayflower recently completed a five- week trip across the Atlantic Ocean without any humans on board. It set off from the British port of Plymouth on April 27 and arrived in the eastern Canadian city of Halifax on June 5. The 15-meter Mayflower is named after a ship that carried a group of European settlers from Plymouth to North America more than 400 years ago. That famous trip, in 1620, prepared the way for Britain’s colonization (殖民) of what Europeans called the New World.

The Mayflower experienced breakdowns on its latest trip, as well as an earlier attempt to cross the Atlantic. The first attempt, in June 2021, was called off after a breakdown forced the ship to return to Plymouth. Later ,during the latest trip, a problem with the ship’s power system led project organizers to send the ship to Portugal’s Azores in the mid-Atlantic. A team member was flown to the area to perform repairs.

More troubles came in late May when the Mayflower developed another power issue. That trouble was also repaired. But the team decided to send the ship on a new path to Halifax Experts say AI is getting much better at helping self- sailing ships understand their surroundings and pilot themselves. But most autonomous systems cannot repair themselves when the engine fails. The Mayflower is equipped with instruments designed to measure the health of ocean water. Such ships could be used to probe into parts of oceans that are too difficult for people to reach.