Krieger (crater)

Krieger is a lunar impact crater of approximately 22 kilometers in diameter, located in the western part of the Oceanus Procellarum. Its rim is irregular and somewhat polygonal in outline, with a small craterlet on the western rim and a notable dark-floored crater on the northern rim. The interior floor is relatively flat but marked by a few small craters, and the walls are low and worn. The crater has a maximum depth of about 2.1 kilometers, which is shallow compared to its diameter, indicating significant infilling by lava flows from the surrounding mare.¹

Krieger lies in the Oceanus Procellarum, a vast lunar mare formed by extensive basaltic volcanism. The crater is situated near the Aristarchus plateau, a region known for its volcanic features and pyroclastic deposits. The dark-floored crater on Krieger's rim, named 'Krieger B', is a small maar-like feature that may be volcanic in origin, possibly a vent for pyroclastic eruptions. The area around Krieger shows evidence of multiple episodes of lava flooding, which has partially buried older craters and shaped the current topography.²

Krieger was first mapped in detail by the German selenographer Johann Nepomuk Krieger, after whom it is named. Krieger was a meticulous observer who produced some of the most accurate lunar drawings of his time, using the 12-inch refractor at the Munich Observatory. His work, published in the early 20th century, contributed significantly to the selenographic mapping of the Moon. The crater was later officially named by the International Astronomical Union in 1935.³

One lesser-known aspect is the presence of a small, dark-haloed crater on Krieger's northern rim, which is a rare feature on the Moon and may indicate explosive volcanic activity. Additionally, Krieger is part of a chain of craters that includes Prinz and Van Biesbroeck, which are thought to share a common origin from a single impact event that fragmented before hitting the surface. The crater's irregular shape has led some researchers to suggest it may be a compound crater formed by multiple impacts. Furthermore, Krieger is a target for remote sensing studies due to its proximity to the Aristarchus plateau, which has been a focus of lunar exploration.⁴

Lunar mare

A large, dark plain on the Moon, formed by ancient volcanic eruptions.

Pyroclastic deposit

Rock fragments and ash ejected during explosive volcanic eruptions.

Selenography

The study of the surface and physical features of the Moon.