A distant, partly shadowed Earth, as viewed from a 6,000-km-altitude orbit. This unusual image was acquired using an extremely miniaturized camera about the size of the edge of a 20 cent coin—a miniscule technology experiment aboard ESA's shoebox-sized TRISAT-R CubeSat.

TRISAT-R project manager Iztok Kramberger of the University of Maribor explains: "This tiny camera measuring less than two cubic millimeters in size took a picture of an object measuring approximately one trillion cubic kilometers—our beautiful planet Earth—from thousands of kilometers away."

A CubeSat made from three standardized 10-cm boxes, TRISAT-R is Slovenia's second space mission, which flew on Europe's inaugural Vega-C launch last year to the relatively inhospitable environment of medium-Earth orbit, at 6000 km up. The mission's orbital path takes it right through the heart of the ionosphere—an electrically active layer of Earth's atmosphere—as well as the inner Van Allen radiation belt.

This allows TRISAT-R to test a suite of radiation-detection payloads. In addition, the TRISAT-R team embarked a pair of tiny cameras, with lenses made from clear borosilicate glass to provide limited radiation resistance, mounted directly onto 320x320 pixel image sensors.

In September 2021, Rwanda announced that it was planning to launch over 300,000 satellites. Three months later, a Canadian company, having previously launched two dozen CubeSats, said it would launch an additional 100,000. Then, a French company did likewise. And SpaceX, which has already launched around 5,000 satellites, now has plans for over 60,000 more.

There are currently only about 8,000 active satellites in orbit. What's going on?

Before a satellite is launched, a nation state must file its proposed satellite system with the International Telecommunication Union (ITU) to coordinate radiofrequency spectrum on behalf of the satellite operator, which could be a company, university or government agency.

These filings are made years ahead of the satellite launch, so the ITU can oversee coordination between different satellite operators and ensure that new satellite signals don't drown existing ones out.

Commercial companies are increasingly becoming involved in transporting astronauts to the International Space Station (ISS), as well as other activities in orbit. Some, such as Houston-based Axiom Space, eventually want to build their own space stations in orbit, where commercial astronauts could make extended stays.

This could also provide more money and opportunities for science to be carried out in low Earth orbit. But it also raises a host of safety concerns, because it will add to the already troublesome issue of space junk. There are also implications for the environment, because rockets produce greenhouse gas emissions that contribute to climate change.

Axiom, which was founded in 2016, was the first company to conduct privately funded missions to the ISS. Under Axiom's Space Access Program, it has been offering different countries the opportunity to design customized missions to orbit aboard SpaceX's Crew Dragon spacecraft. As such, it recently signed an agreement with the UK Space Agency for an all-UK astronaut mission to the ISS.

Landing safely on an asteroid is no mean feat. Despite several recent successes, there have also been notable failures—most famously, the Philae lander to 67P/Churyumov-Gerasimenko. Admittedly, that was an attempt to land on a comet rather than an asteroid, but those two bodies share many of the same landing hazards.

One of the most prevalent problems is "inhomogenous" gravity. Offering a solution, researchers from the Harbin Institute of Technology in China recently published a paper in Aerospace Science and Technology detailing a framework for performing "soft landings" on asteroids, which might help make exploring these rocky worlds much more accessible.

First, it would be helpful to understand the difference between a "hard" landing on an asteroid and a "soft" landing. A hard landing consists of the spacecraft, either in a controlled or uncontrolled descent, landing with some force on the asteroid's surface.