Operating a vehicle that is orbiting the Earth 438 miles overhead at 17,000 miles per hour is not your average day job. Managing the Landsat satellites that are daily imaging the Earth’s surface is part of the USGS program’s responsibilities. Each mission is designed to endure the extremes of the space environment through robust design including some system redundancies. Landsat 5’s distinguished 29-year mission demonstrated not only the benefits of redundant design features but also the value of a skilled and creative flight operations team. Landsat 7 and Landsat 8 are the current missions to continue this challenge of maximizing mission life.
While Landsat 5 was designed for a 3-year mission life, both Landsat 7 and Landsat 8 were designed for a minimum 5-year mission life. Landsat 7 has collected over 2 million scenes after 17 years in orbit. By chance Landsat 5 and by design Landsat 8 were each launched with additional fuel that is required for the spacecraft to maintain a precise orbit for Earth imaging. Landsat 7 is now drawing down its fuel reserve late in the mission. The flight operations team has investigated a number of options to optimize fuel use with the goal of maximizing Landsat 7’s operational life. Landsat 7 successfully performed its 19th inclination maneuver that positions the satellite to potentially continue its mission into 2020—more than 21 years following its launch. The Landsat 8 spacecraft was designed for a 5-year design life; however, due to time constraints, its thermal imaging instrument, known as the Thermal Infrared Sensor (TIRS), was designed for a 3-year life.
The USGS Landsat team, along with NASA and the spacecraft vendors, continued to meet the challenges of space operations in 2016 and will continue to build on that record in the future. Additional time added to a mission’s operation provides more imagery for operational and science applications, a benefit to users and the American taxpayer.