Category: News

Week in images: 04-08 August 2025

Discover our week through the lens

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Last July, a team of robots explored a simulated martian landscape in Germany, guided by an astronaut aboard the International Space Station. This was the final session of the Surface Avatar experiment, a joint initiative between ESA and the German Aerospace Center (DLR) to investigate how astronauts can remotely control robotic teams.

This latest session took place at the DLR site in Oberpfaffenhofen and introduced new levels of autonomy, decision-making and realism, bringing Europe one step closer to seamless human-robot collaboration in space exploration.

Astronomers using the NASA/ESA/CSA James Webb Space Telescope have found strong evidence of a giant planet orbiting a star in the stellar system closest to our own Sun. At just 4 light-years away from Earth, the Alpha Centauri triple star system has long been a compelling target in the search for worlds beyond our solar system.

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A team of astronomers has taken the sharpest-ever picture of the unexpected interstellar comet 3I/ATLAS, using the crisp vision of the NASA/ESA Hubble Space Telescope.

ESA’s Planetary Defence Office responded promptly to the discovery of the comet, and has been tracking it since the beginning of July.

Now, Hubble’s observations from space are allowing astronomers to more accurately estimate the size of the comet’s solid icy nucleus. The upper limit on the diameter of the nucleus is 5.6 km, but it could be as small as 320 m across, researchers report.

Though the Hubble images put tighter constraints on the nucleus size compared to previous ground-based estimates, the solid heart of the comet presently cannot be directly seen, even by Hubble. Further observations, including by the NASA/ESA/CSA James Webb Space Telescope, will help refine our knowledge about the comet, including its chemical makeup.

Hubble also captured a dust plume ejected from the Sun-warmed side of the comet, and the hint of a dust tail streaming away from the nucleus. Hubble’s data show that the comet is losing dust in a similar manner to that from previously seen Sun-bound comets originating within our Solar System.

The big difference is that this interstellar visitor originated in some other stellar systems, elsewhere in our Milky Way galaxy.

3I/ATLAS is traveling through our Solar System at roughly 210 000 km per hour, the highest speed ever recorded for a Solar System visitor. This breathtaking sprint is evidence that the comet has been drifting through interstellar space for many billions of years. The gravitational slingshot effect from innumerable stars and nebulae the comet passed added momentum, ratcheting up its speed. The longer 3I/ATLAS was out in space, the higher its speed grew.

This comet was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) on 1 July 2025 at a distance of 675 million km from the Sun. 3I/ATLAS should remain visible to ground-based telescopes until September, after which it will pass too close to the Sun to observe. It is expected to reappear on the other side of the Sun by early December.

Icy wanderers such as 3I/ATLAS offer a rare, tangible connection to the broader galaxy. To actually visit one would connect humankind with the Universe on a far greater scale. To this end, ESA is preparing the Comet Interceptor mission. The spacecraft will be launched in 2029 into a parking orbit, lying in wait for a suitable target – a pristine comet from the distant Oort Cloud that surrounds our Solar System, or, unlikely but highly appealing, an interstellar object.

While it is improbable that we will discover an interstellar object that is reachable for Comet Interceptor, as a first demonstration of a rapid response mission that waits in space for its target, it will be a pathfinder for possible future missions to intercept these mysterious visitors.

The research paper based on Hubble observations will be published in The Astrophysical Journal Letters.

[Image description: At the center of the image is a comet that appears as a teardrop-shaped bluish cocoon of dust coming off the comet’s solid, icy nucleus and seen against a black background. The comet appears to be heading to the bottom left corner of the image. About a dozen short, light blue diagonal streaks are seen scattered across the image, which are from background stars that appeared to move during the exposure because the telescope was tracking the moving comet.]

Europe’s first MetOp Second Generation, MetOp-SG-A1, weather satellite – which hosts Copernicus Sentinel-5 as part of its instrument package – is set for liftoff on an Ariane 6 rocket from Europe’s Spaceport in Kourou, French Guiana, on 13 August 2025 at 02:37 CEST (12 August 21:37 Kourou time).

Watch live on ESA Web TV One.

ESA’s Hera mission has captured images of asteroids (1126) Otero and (18805) Kellyday. Though distant and faint, the early observations serve as both a successful instrument test and a demonstration of agile spacecraft operations that could prove useful for planetary defence.

Hera is currently travelling through space on its way to a binary asteroid system. In 2022, NASA’s DART spacecraft impacted the asteroid Dimorphos, changing its orbit around the larger asteroid Didymos. Now, Hera is returning to the system to help turn asteroid deflection into a reliable technique for planetary defence.

In its latest postcard from Mars, the European Space Agency’s Mars Express returns to Acheron Fossae: a dramatic network of chasms carved into the surface of the Red Planet.

As preparations to launch Europe’s first MetOp Second Generation, MetOp-SG-A1, satellite continue on track, the team at Europe’s Spaceport in Kourou, French Guiana, has bid a heartfelt farewell to this precious satellite as it was sealed from view within the Ariane 6 rocket’s fairing.

This all-new weather satellite, which hosts the first Copernicus Sentinel-5 instrument, is set to take to the skies on 13 August at 02:37 CEST (12 August 21:37 Kourou time).

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This summer, a team of robots explored a simulated martian landscape in Germany, remotely guided by an astronaut aboard the International Space Station. This marked the fourth and final session of the Surface Avatar experiment, a collaboration between ESA and the German Aerospace Center (DLR) to develop how astronauts can control robotic teams to perform complex tasks on the Moon and Mars.

The session introduced new levels of autonomy and complexity. NASA astronaut Jonny Kim operated two robots – ESA’s four-legged Spot and DLR’s humanoid Rollin’ Justin – to retrieve scattered sample containers and deliver them to a lander. Spot navigated the terrain autonomously, while Justin was guided through a mix of direct control and pre-set commands. This setup allowed Jonny to delegate tasks and focus on higher-level decisions, building on other sessions where robots required full teleoperation.

In a second scenario, ESA’s Interact rover transported DLR’s robot dog Bert to a cave entrance. After removing a boulder, Jonny deployed Bert, which then simulated a malfunction in one of its legs. Jonny had to retrain Bert’s walking algorithm in real time before it continued into the cave and detected signs of martian ice. This tested how operators respond to unexpected challenges and adapt robotic systems on the fly.

The robots are controlled from the International Space Station using a custom-built interface developed by ESA and DLR, combining a joystick and a haptic-feedback device. The interface allows switching between first-person view for immersive teleoperation and a top-down map for broader mission oversight. This flexibility lets the astronaut manage multiple robots efficiently, balancing direct control with strategic delegation.

Over four sessions, the Surface Avatar team has refined its approach to human-robot interaction, improving both teleoperation and task delegation to autonomous systems. The experiment has also helped to identify which tasks astronauts prefer to control directly and which can be safely handed over to robotic systems, offering valuable insight for future mission planning.

Read our blog to find out more.

Week in images: 28 July – 1 August 2025

Discover our week through the lens

Data from ESA’s Soil Moisture and Ocean Salinity (SMOS) mission can be used to estimate how much carbon is stored in forests – and a study has improved our understanding of how reliable this proxy is and how long-term datasets from SMOS can help us to monitor this valuable resource.

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Webb takes a fresh look at a classic deep field