On Feb. 14, NASA's Lucy spacecraft, which is in the first few months of its journey to the Trojan asteroids, obtained a series of calibration images with its four visible-light cameras.

The Hubble space telescope has a primary mirror of 2.4 meters. The Nancy Grace Roman telescope also has a mirror measuring 2.4 meters, and the James Webb Space Telescope has a whopping 6.5 meter primary mirror. They get the job done that they were designed to do, but what if… we could have even bigger mirrors?

The larger the mirror, the more light is collected. This means that we can see farther back in time with bigger mirrors to observe star and galaxy formation, image exoplanets directly, and work out just what dark matter is.

But the process for creating a mirror is involved and takes time. There is casting the mirror blank to get the basic shape. Then you have to toughen the glass by heating and slow cooling. Grinding the glass down and polishing it into its perfect shape comes next followed by testing and coating the lens.

This artificial bone sample is an early step towards making 3D bioprinting a practical tool for emergency medicine in space. An ESA R&D effort aims to develop bioprinting techniques capable of giving astronauts on an extended mission ready access to the "spare parts" needed for bone or skin grafts, and even complete internal organs.

3D bioprinting may soon be practical on Earth, and could help meet the challenging conditions of spaceflight. Astronauts in zero or low gravity lose bone density, for example, so fractures may be more likely in orbit or on Mars.

Or, treating a burn often involves a graft of skin taken from a patient's body—manageable on Earth with full hospital care but more risky in space, as the secondary damage may not heal easily.

Skin or bone can be bioprinted using a nutrient-rich "bio-ink" of human blood plasma, available from the astronauts themselves. By working upside down—in "minus 1g" gravity—the team has shown they can probably do it in space.

This bone sample is part of the first selection of items on the 99 Objects of ESA ESTEC website, a set of intriguing, often surprising artifacts helping tell the story of more than half a century of activity at ESA's technical heart.

The Axiom-1 mission to send four private astronauts to the International Space Station is the first of many missions planned by NASA to expand the ISS for commercial use as part of what's being called the low-Earth orbit economy.

The commander of the Axiom-1 mission has emphatically stated that this is not an example of space tourism, as the crew have undergone training and the mission includes plans to conduct biomedical research.

Crew members—all men aged 52 to 71—reportedly paid a whopping US$55 million (£42.3 million) per ticket, an amount that would no doubt fund a formidable biomedical research program here on Earth. But beyond the ludicrous ticket price, I'm concerned about the potential environmental impacts of such space jaunts.