The recently decommissioned Landsat 7 satellite has provided a stunning final glimpse of Las Vegas, Nevada, showcasing the city's rapid expansion over its 25-year operational lifespan. The last image, taken on May 28, 2024, captures the vibrant growth of Las Vegas, juxtaposed against one of the satellite's first photographs from July 4, 1999. This comparison highlights the remarkable transformation of the area, once a modest desert town, now sprawling across the Mojave Desert.
Landsat 7 is an Earth-observing satellite, co-owned by NASA and the U.S. Geological Survey (USGS), that has been pivotal in monitoring Earth's landscapes. Launched on April 15, 1999, the satellite has orbited the planet approximately every 99 minutes, capturing more than 3.3 million images of the Earth’s surface. It has played an essential role in various applications, including environmental monitoring, land-use planning, and disaster response.
On June 4, Landsat 7 transmitted its final signals, officially marking the end of its mission after a year-long decommissioning process. This process ensured the satellite was safely maneuvered out of the way of operational satellites before it depleted its fuel. According to USGS, Landsat 7 is expected to drift in space for around 55 years before it ultimately reenters the atmosphere and burns up.
The final image of the Las Vegas metropolitan area illustrates the city's growth, including prominent neighborhoods like Henderson, Paradise, and Spring Valley. Comparing the last photo with one taken in 1999 reveals that Las Vegas has nearly doubled in size. Between 2000 and 2023, the population in this region surged from 1.38 million to 2.33 million, marking an impressive 69% growth. Projections indicate that by 2025, approximately 2.4 million people will reside in the area.
Both satellite images prominently feature Lake Mead, an artificial reservoir formed by the Hoover Dam. However, the latest image reveals a concerning trend: the lake appears significantly smaller than in previous years. This change may be attributed to increased water consumption in the region or the effects of human-induced climate change. Nevertheless, fluctuations in the lake's size are common, influenced by seasonal and annual variations, making it challenging to ascertain the precise impact of anthropogenic factors, as noted by NASA's Earth Observatory.
Landsat 7 is the seventh satellite in the esteemed Landsat program, which has been capturing images of Earth's surface since 1972. It was designed as a significant upgrade over its predecessors, particularly excelling in capturing urban landscapes, which has been crucial for mapping services like Google Maps. The satellite has documented significant historical events, including the 9/11 terror attacks, Hurricane Katrina, and the Deepwater Horizon oil spill.
Despite being designed for a mere five-year mission, Landsat 7 exceeded expectations, although it did face an instrument failure in 2003, which was later repaired. While NASA considered a pioneering refueling operation to extend its lifespan, this maneuver was ultimately never executed. Currently, only two operational Landsat satellites remain in orbit: Landsat 8, active for over 12 years, and Landsat 9, which was launched in September 2021.
The legacy of Landsat 7 will continue to inform scientists and researchers as they monitor environmental changes and urban development worldwide, marking a significant chapter in Earth's observational history.
