WASHINGTON — A decommissioned NASA satellite, launched nearly four decades ago, is predicted to re-enter late Jan. 8 with very little risk to people on the ground.
NASA said on January 6 that the Earth Radiation Budget Satellite (ERBS), which was launched in 1984 and retired in 2005, will re-enter on January 8. At the time, NASA estimated a reentry at 6:40 p.m. Eastern, plus or minus 17 hours, based on US Space Force data.
The Space Force’s Space Track service updated this prediction late on January 6, with a new reentry time of 11:25 PM Eastern plus or minus 10 hours. The Aerospace Corporation’s Center for Orbital and Reentry Debris Studies estimated a reentry at 10:49 PM Eastern plus or minus 13 hours, based on data from early January 6.
Most of the 2,450-kilogram satellite will burn up on reentry, NASA said in its statement, but some components will likely survive and reach the surface. The chance that debris will injure someone on the ground is 1 in 9,400, the agency estimated.
ERBS was launched on the space shuttle Challenger in October 1984 to study the balance between energy absorbed by the Earth from the sun and energy radiated away, as well as to monitor ozone in the stratosphere. ERBS was intended to operate for two years, and was finally retired in 2005.
NASA launched ERBS before the agency’s first Orbital Debris Reduction Guidelines in the 1990s. Current U.S. government Orbital Debris Mitigation Standard Practice, last updated in 2019, requires that low-Earth orbit satellites be dismantled no more than 25 years after the end of the mission, which ERBS will meet. However, ERBS does not meet another aspect of the guidelines, limiting the risk of injury from falling debris to no more than 1 in 10,000.
There has been a long-standing discussion of reducing the post-mission lifetime limit from 25 years to as little as 5 years to minimize the risk of collisions that could create debris. A National Orbital Debris Implementation Plan, published by the White House Office of Science and Technology Policy in July 2022, directed NASA and several other agencies to reevaluate existing mitigation policies, “specifically the potential benefits and costs of reducing deorbit timelines.”
In September 2022, the Federal Communications Commission approved an order requiring commercial satellites applying for FCC licenses or seeking US market access after September 2024 to decommission their satellites no more than five years after the end of their missions. That rule applies to satellites that end their lives at altitudes of 2,000 kilometers or less.