Even as Google plans to test its fleet(车队) of self-driving cars on public roads this summer, its business model remains a bit of a mystery. By 2025, as many as 250,000 self-driving vehicles could be sold each year globally, according to a study by an industry research firm.

"Vehicles that can take anyone from A to B at the push of a button could transform mobility for millions of people," said Chris Urmson, director of Google's self-driving car project. For now, Google has no plans to sell any of its self-driving cars. They are strictly for research. But they will hit public roads this summer near Google's headquarters in Mountain View, California. Previous testing has taken place only on closed courses.

The cars are built to operate without a steering wheel, accelerator(油门) or brake pedal. "Our software and sensors do all the work," Urmson said. "The vehicles will be very basic—we want to learn from them and adapt them as quickly as possible—but they will take you where you want to go at the push of a button." The prototypes(雏形) are the first of a 100-car fleet the tech giant is building.

In the long run, Urmson sees a future of safer roads — the majority of auto accidents are caused by human error — and fewer traffic jams. Robotic cars could also shuttle people who can't drive because of age or illness.

Google has said that self-driving cars could launch new business models in which people buy the use of vehicles they don't own. The company has already tested other types of self-driving cars on public streets, including modified Lexus sport-utility vehicles, under a special permit program by the California Department of Motor Vehicles that requires a human driver at the controls.

The state has issued six other companies permits to operate such cars, including Delphi, Mercedes-Benz, Volkswagen, Tesla, Bosch and Nissan. The vehicles that will be tested on open roads this summer will have removable steering wheels, accelerator and brake pedals to allow "safety drivers" to take control if needed.

Google says the cars are safe. The vehicles have sensors that "can detect objects out to a distance of more than two football fields in all directions, which is especially helpful on busy streets with lots of intersections," Urmson said. "We're looking forward to learning how the community understands and interacts with the vehicles, and to uncovering challenges that are unique to a fully self-driving vehicle," Urmson said.

Astronauts on the International Space Station (ISS) will soon test a new oven for making chocolate chip cookies. A spaceship carrying the cooking equipment and other supplies was launched on Saturday from the Wallops Flight Facility in the United States. The shipment, weighing 3,700 kilograms, reached the space station on Monday. The goal is to explore the possibility of making freshly baked cookies for space travelers.

American company Nanoracks designed and built the oven and helped with organizing the flight to the space station. Hilton Double Tree hotels supplied the cookie dough (生面团) the astronauts will use.

In the past, space station crews have created their own pizzas using a thin, fiat piece of bread known as flatbread. Astronauts have tried other creative ways to make food, such as creating salads from vegetables grown in the space station. Results have been mixed.

The cookie baking will be a slow process. The oven can heat just one cookie at a time. The test could take weeks before the astronauts have chance to try out freshly baked cookies.

Five unbaked cookies have been in a space station freezer for several weeks. Each is in its own individual clear bag made out of silicone. The oven can heat foods to temperatures as high as 177°C. That is twice the temperature of the U.S. and Russian food warmers on the space station. The oven uses electric heating elements.

Mary Murphy is with Nanoracks. Murphy says she expects a baking time of 15 to 20 minutes for each cookie when the oven is heated to about 163°C. She adds that the smell of baking cookies should fill the space station each time a cookie comes out of the oven.

The oven’s first use will be the real test. Without the force of gravity, the astronauts do not know exactly how the cookie will look. Three of the space-baked cookies are to be returned to Earth for testing.

Researchers have been looking into silicon carbide(碳化硅), a promising alternative material for the semiconductor (半导体) industry, for several years now. Size, weight and efficiency are three important factors for power electronic to fit in e-cars. Silion carbide meets all three factors. It is more efficient but leaves a smaller footprint than conventional semiconductors such as silicon.

Even so, silicon carbide isn’t to be found in any e-cars on the road today. This semiconductor material is still limited to research labs. To shift it from the lab to the factory, the Si on Carbide Module (模块) project has taken into consideration all the conditions of industrial production. The module's design is a good case: researchers at the Fraunhofer IZM are basing it on the structure of the classic printed circuit board that the industry has long favored. This should speed up its first display.

The module is also benefiting from the latest scientific advances. Instead of wire-bonding the semiconductor to the package, the researchers decided to put it directly in the circuit. The team also brought the potential customers on board for this development effort. In the project’s first year, they drew up a specification (规格) sheet illustrating the requirements for the module and semiconductor. The researchers worked closely with users, catering to their wishes when they determined the product specification.

Automakers, component suppliers and OEMS were directly involved in the effort to map out the power-electronic module’s size, layout and electrical circuits. The group sought to make the most of the space available in the vehicle’s power train. Lars Bottcher, group leader at the Fraunhofer IZM and head of the SiC sub-project, says, “The major goal is to advance the new semiconductor material silicon carbide to mass production.”