The shortfall comes despite a ten-fold increase in Nasa’s annual budget over the past five years – from $4m (£2.5m) in 2009 to $40m (£25m) in 2014 – to track and assess potentially dangerous asteroids and comets. So-called “near-earth objects”, or NEOs, fly within about 28m miles (45m km) of Earth.
The agency’s efforts are poorly coordinated, ill-managed and under-staffed, according to a 32-page report called NASA’s Efforts to Identify Near-Earth Objects and Mitigate Hazards by Nasa inspector general Paul Martin.
“Nasa estimates that it has identified only about 10% of all asteroids 140 metres and larger,” Martin wrote. “Given its current pace and resources, (Nasa) has stated that it will not meet the goal of identifying 90% of such objects by 2020.”
A one-person office manages a “loosely structured conglomerate of research activities that are not well integrated and (which) lack overarching program oversight, objectives and established milestones to track progress,” the report said.
Nasa has found about 95% of the largest and potentially most destructive asteroids, those measuring about 0.62 miles (1 km) or larger in diameter.
About 66 million years ago, a 6.2 mile (10 km) -wide object hit what is now Mexico’s Yucatan peninsula, triggering global climate changes that are believed to have led to the demise of the dinosaurs and most other species alive at that time.
More recently, a fragment of an asteroid estimated to be only 59 feet (18 metres) in diameter exploded over Chelyabinsk, Russia on 15 February 2013. The force of the explosion matched the energy released in 30 atomic bombs, blowing out windows and destroying buildings. More than 1,000 people were injured by flying debris.
“Recent research suggests that Chelyabinsk-type events occur every 30 to 40 years,” the Office of Inspector General report said, adding that most impacts would occur in the ocean rather than in populated areas.
Since 1998, Nasa has spent about $100m on programs to find, assess and mitigate potentially threatening space neighbours.
As of July 2014, the agency has discovered about 11,230 NEOs, including 862 of the largest asteroids. That figure includes only about 10% of smaller nearby asteroids that are about 460 feet (140 metres) wide, far short of the agency’s goal to find 90% by 2020, the report said.
The report made five recommendations for beefing up Nasa’s asteroid detection efforts, including adding at least four to six employees to help manage the program and coordinating projects with other US and international agencies and with privately funded initiatives.
Nasa’s associate administrator for science, John Grunsfeld, said in a letter to Martin he expects a new NEO program to be in place by 1 September 2015.