BY:SpaceEyeNews.
The BELA laser has awakened aboard BepiColombo, bringing Mercury’s future 3D survey a crucial step closer. On September 14, 2026, engineers successfully fired the instrument roughly 200 million kilometers from Earth. Its laser had remained silent since 2017. Now, the team has confirmed that it can operate after almost eight years in space. The next challenge is turning those pulses into precise measurements of Mercury’s landscape.
BELA Laser Passes Its First Space Test
A Careful Restart After Years of Waiting
BELA’s first firing in space began with a deliberately short test. Engineers commanded a burst lasting ten seconds, sending infrared pulses into open space. The instrument monitored those pulses to assess the laser’s condition.
Crucially, the light came from BepiColombo itself. Scientists did not send a beam from Earth across the entire distance. Nor did the test pulses reach Mercury’s surface.
After receiving reassuring data, controllers repeated the short sequence. They then extended operation to ten minutes before allowing the laser to run for more than an hour.
Reliable Performance Through Longer Tests
Each stage gave engineers another opportunity to check the system before proceeding. Temperature behavior mattered alongside the laser’s ability to fire.
The results matched expectations. BELA operated reliably, while its thermal response stayed within predicted limits.
For the team, that steady performance represented a major achievement. Hardware that last fired before launch had successfully resumed operation after its long journey. The University of Bern’s announcement confirms the successful sequence.
How the BELA Laser Will Map Mercury
Turning Travel Time Into Elevation
Once science operations begin, BELA will direct infrared pulses toward Mercury. It will measure how long reflected light takes to return.
Those timings reveal the distance between the spacecraft and the terrain below. Combined with the spacecraft’s position, repeated measurements will help establish surface elevations.
The result will be a detailed framework for describing Mercury’s shape. Instead of relying only on how features appear in images, researchers can compare their measured heights and profiles.
That distinction matters when examining uneven terrain. A crater’s outline tells only part of its story. Its depth, slopes, and surrounding elevations add another dimension.
Combining Measurements With Images
BELA will work alongside other instruments aboard ESA’s Mercury Planetary Orbiter, or MPO. Stereo imaging and radio science will complement its elevation measurements.
Together, these datasets can connect local features with the planet’s wider structure. The instrument team identifies this combined approach as central to BELA’s scientific value in its official science overview.
What Mercury’s Landscape Could Reveal
Reading the Shape of the Surface
BELA’s goals extend beyond producing an attractive map. Researchers want to measure surface roughness, local slopes, and variations in reflected light.
These properties provide different ways to characterize terrain. They can help scientists compare geological features and investigate how Mercury’s landscape developed.
The instrument’s objectives also include observations of permanently shaded craters near the poles. Such measurements would add useful information about terrain where sunlight never directly reaches the ground.
However, a measured shape does not automatically identify its origin. Scientists must interpret topography alongside imagery and other evidence. That combination helps them test explanations rather than infer geological history from appearance alone.
Connecting Surface Changes With the Interior
Another objective concerns tidal deformation: subtle changes in Mercury’s shape under gravitational forces.
Tracking that response can contribute to studies of the planet’s internal structure. BELA will support this effort through measurements that researchers combine with other geophysical observations.
These remain scientific goals. The September activation did not detect tidal changes or reveal a new interior model.
Still, the connection makes the instrument especially interesting. Measurements of the surface may eventually help researchers investigate conditions far beneath it. BELA’s science objectives explicitly include tidal deformation and contributions to interior studies.
The Final Steps Before Mercury Mapping
From Cruise to Separate Orbiters
BepiColombo launched on October 20, 2018, carrying two scientific orbiters toward Mercury. ESA provided MPO, while JAXA supplied the Mercury Magnetospheric Orbiter, known as Mio.
The Mercury Transfer Module supported their journey. It separated from the orbiters on September 3, 2026, marking another important transition.
BELA’s successful activation followed eleven days later. Together, these milestones move the mission closer to its planned observing phase.
When Science Operations Should Begin
The University of Bern’s September announcement places Mio’s deployment into its operational orbit on December 9, 2026. Further maneuvers should bring MPO into its science orbit in March 2027.
The same announcement schedules the formal science phase for April 6, 2027. These dates describe the current plan, rather than completed milestones.
Before routine mapping can begin, the spacecraft must complete those preparations. BELA must then collect returning signals from Mercury under actual observing conditions. The detailed schedule appears in the official mission update from Bern.
The team also brings a long development history to this moment. BELA left Bern for spacecraft integration in September 2016. Its builders include the University of Bern and the German Aerospace Center, alongside partners in Germany and Spain. Their shared effort now approaches the stage when engineering performance becomes scientific opportunity.
What the Successful Test Actually Proves
The activation confirms that BELA’s laser can operate after years without firing. It also shows that the system behaved as expected during progressively longer tests.
It does not yet establish the quality of a finished Mercury map. That requires surface measurements, accurate positioning, and careful processing.
Similarly, projected improvements in mapping remain expectations until researchers evaluate operational data. This distinction preserves the significance of the news: an essential instrument has passed an important readiness check.
BELA Laser Opens the Next Chapter
The BELA laser has moved from years of waiting to successful operation in space. Its next assignment will demand sustained measurements above Mercury’s varied terrain. Those observations could strengthen studies of surface geology, planetary shape, and internal structure. For now, the achievement is clear: the laser works, and the team can advance toward the science that motivated its long journey.
Main Sources:
- University of Bern — BELA ready to explore Mercury’s surface
Official announcement confirming the laser activation, test results, and planned science timeline. - University of Bern — BELA Science Objectives
Scientific goals covering surface mapping, tidal deformation, and Mercury’s interior. - University of Bern — BepiColombo Laser Altimeter: Instrument Overview
Background on BELA, its development partners, and its role aboard BepiColombo.