【推荐1】Bacteria are an annoying problem for astronauts. The microorganisms (微生物) from our bodies grow uncontrollably on surfaces of the International Space Station, so astronauts spend hours cleaning them up each week. How is NASA overcoming this very tiny big problem? It’s turning to a bunch of high school kids. But not just any kids. It is depending on NASA HUNCH high school classrooms, like the one science teachers Gene Gordon and Donna Himmelberg lead at Fairport High School in Fairport, New York.

HUNCH is designed to connect high school classrooms with NASA engineers. For the past two years, Gordon’s students have been studying ways to kill bacteria in zero gravity, and they think they’re close to a solution (解决方案). “We don’t give the students any breaks. They have to do it just like NASA engineers,” says Florence Gold, a project manager.

“There are no tests,” Gordon says. “There is no graded homework. There almost are no grades, other than ‘Are you working towards your goal?’ Basically, it’s ‘I’ve got to produce this product and then, at the end of year, present it to NASA.’ Engineers come and really do an in-person review, and...it’s not a very nice thing at times. It’s a hard business review of your product.”

Gordon says the HUNCH program has an impact (影响) on college admissions and practical life skills. “These kids are so absorbed in their studies that I just sit back. I don’t teach.” And that annoying bacteria? Gordon says his students are emailing daily with NASA engineers about the problem, readying a workable solution to test in space.

【推荐3】Space is becoming more crowded. Quite a few low-Earth-orbit (LEO) satellites have been launched into the sky, which are designed to move around the Earth only a few hundred kilometres above its surface. SpaceX and OneWeb plan to launch LEO satellites in their thousands, not hundreds, to double the total number of satellites in orbit by 2027.

That promises to change things on Earth. LEO satellites can bring Internet connectivity to places where it is still unavailable. This will also be a source of new demand for the space economy. Morgan Stanley, a bank, projects that the space industry will grow from $350 billion in 2016 to more than $1.1 trillion by 2040. New Internet satellites will account for half this increase.

For that to happen, however, three worries must be overcome. Debris (碎片) is the most familiar concern. As long ago as 1978, Donald Kessler, a scientist at NASA, proposed a scenario (设想) in which, when enough satellites were packed into low-Earth orbits, any collision could cause a chain reaction which would eventually destroy all spacecraft in its orbital plane. Solutions exist. One solution is to grab the satellites with problems and pull them down into the Earth’s atmosphere. Another is to monitor space more closely for debris. But technology is only part of the answer. Rules are needed to deal with old satellites safely from low-Earth orbits.

Cyber-security is a second, long-standing worry. Hackers could take control of a satellite and steal intellectual property, redirect data flows or cause a collision. The satellite industry has been slow to respond to such concerns. But as more of the world’s population comes to rely on space for access to the Internet, the need for action intensifies. Measures will surely be taken to protect network security.

The third issue follows from the first two. If a simple mistake or a cyber-attack can cause a chain reaction which wipes out hundreds of billions of dollars of investment, who is responsible for that? Now the plans of firms, wishing to operate large numbers of satellites are being studied. But there is a long way to go before the risks are well understood, let alone priced.

As space becomes more commercialized, mind-bending prospects open up: packages moved across the planet in minutes by rocket rather than by plane, equipment sent to other small planets, passengers launched into orbit and beyond. All that and more may come one day. But such activities would raise the same questions as LEO satellites do. They must be answered before the space economy can truly develop.