Space News & Blog Articles

How great are wheels, really? Wheels need axles. Suspension. Power of some kind. And roads, or at least swaths of relatively flat and stable terrain. Then you need to maintain all of it. Because of their cost many civilizations across human history, who knew all about wheels and axles, didn’t bother using them for transportation. Another way to look at it – much of human technology mimics nature. Of the simple machines, levers, inclined planes, wedges, and even screws are observed in nature. Why not the wheel?

The main competition to wheels are legs, which to be fair are also a total nightmare. Whether using the wetware of a horse’s brain or the software of an Atlas robot, legs mean greater demand for computing power to maintain balance under different conditions and loads. Plus the “suspension” gets super complex, often requiring a spine or similar structure that is prone to single-point failure.

So how about jumping? It can take fewer moving parts than rolling or walking, saving weight and removing points of failure. While balancing becomes more critical, it also becomes simpler. Low obstacles become nearly as insignificant as level terrain. And most surfaces you can walk on or roll over, you can also bounce on. The biggest issue is the explosive power required, but even this is being addressed with strategies like stutter jumping.

There have been many successful jumping robot technology demonstrators, like Salto, LSJR, and prototypes from of MIT’s Leg Lab and Sandia Lab’s Intelligent Systems and Robotics Center. More common today are robots which can, but do not exclusively, jump, like Sand Flea, RHex, and Festo’s Kangaroo. And in the world of toys, jumping robots can be mailed to your home with just a few clicks.

Do you need legs to jump? Not really. Ever played with a “jumping popper?” Researchers at Harvard’s Wyss Institute have successfully combined this technology with…explosions and 3-D printing. Another strategy is to gradually spin up and abruptly stop internal flywheels, which comically but effectively flings the rover in a desired direction.

Scientists at the Shanghai Academy of Spaceflight Technology (SAST) have devised an ingenious way to combat the growing problem of space debris. The team fitted a drag sail to a Long March 2 rocket and successfully launched it in July this year. Rocket launches often leave discarded booster stages in low-earth orbit, adding to the pollution of near-earth space. The pilot testing for the sail came as a surprise to many space agencies when, a day after the rocket’s launch, the 25 square meters deorbiting sail was unfolded.

To understand how the sail works, it helps to have an idea of the type of collateral debris that is generated every time a rocket is sent into space. It takes a lot of fuel to shoot heavy objects high enough out of the atmosphere to reach orbital space. These fuel tanks are heavy and must be discarded as soon as they are empty, so that the rocket can reach it’s intended altitude. These empty stages, and other discarded parts like payload adaptors, are left behind and orbit the earth until they eventually de-orbit and break up as they re-enter. However, this process can take many years, and so the volume of space debris is growing rapidly.

The growing debris orbiting earth threatens very real risk to operational space craft in LEO

The way the drag sail works is to create friction against the thin upper atmosphere, which slows the payload adaptor down in the course of its orbital journey. As we know from high-school physics, objects that contend with more atmospheric resistance, will slow down faster and come back to ground sooner. The sail is made of a fine, durable membrane that unfurls to create drag, and increase the speed at which the object will de-orbit.   

Although it has long been theorised, the successful deployment of this sail represents a breakthrough as this new technology may help to solve the mounting “space-junk” problem in Earth’s low orbit. The less time debris spends in orbit, the lower the chance it has of hitting an active satellite and creating a chain reaction. It also presents companies and organisations with an affordable option to “clean up behind themselves” in future.

A NASA scientist is finding newly formed lakes in Alaska that are belching greenhouse gases at a high rate. The main one is methane, a gas many people use in their natural gas-fueled grills. She’s tracking these emissions in one of Earth’s most remote regions—the Arctic. It has millions of lakes, many of them hundreds or thousands of years old. But, only the youngest of them are releasing high amounts of methane. And that is due to the effects of climate change on these delicate environments.

Katey Walter Anthony is an ecologist at the University of Alaska-Fairbanks working with NASA to study this region. She points out that the appearance of younger, methane-belching lakes is a harbinger of things to come. “So that’s a concern for the future, when we think about permafrost carbon feedback, are areas that are newly thawed,” she said.

One of Walter Anthony’s jobs is to sample the gas content at the lakes in the region using methane collection devices that bob on the surface of the water. The bottles will be taken to the lab and the gas analyzed. But, in the field there’s a quick way to tell how much methane is in the lake: simply light a match at the end of the bottle’s valve. A flame flares out in the presence of methane, almost like lighting a camp stove.

Turning the valve on a bubble trap in Big Trail lake releases methane gas, which is flammable. Holding a match near the valve ignites the gas in a burst of flame. Credit: NASA / Sofie Bates

Climate change and Permafrost Thaw = More Methane

Walter Anthony has been studying Big Trail Lake in Alaska. It’s a good example of a methane-rich thermokarst lake that formed less than 50 years ago, she said. Big Trail is one of several at the focus of NASA’s Arctic Boreal Vulnerability Experiment (ABoVE) project which looks at how quickly climate change is affecting the Arctic regions. The “symptoms” of this change are reduced Arctic sea ice, thawing of permafrost soils, decomposition of long-frozen organic matter, widespread changes to lakes, rivers, coastlines, and alterations of ecosystem structure and function. The ABoVE project has been conducting an airborne campaign since 2017 as part of NASA’s Terrestrial Ecology program. It studies parts of Alaska and Western Canada.