By Andrea Shalal

WASHINGTON, Sept 16 (Reuters) - The U.S. Air Force plans to request initial funding for three surveillance satellites to track objects in space as part of its fiscal 2016 budget request, a top Air Force general said Tuesday.

General John Hyten, head of Air Force Space Command, told the annual Air Force Association conference the satellites would be a relatively inexpensive follow-on to the Space-Based Space Surveillance (SBSS) satellite built by Boeing Co.

Hyten declined to give details on the amount of funding required for the new program in the 2016 budget, but said it would clearly be less than the earlier program.

He said the new satellites would build on capabilities to be demonstrated by the Operationally Responsive Space 5 satellite, which is due to be launched in 2017.

The three new satellites would be launched into a low-earth orbit act as "vacuum cleaners" and give the Air Force some additional surveillance capability early next decade, he said.

He said the Air Force could still face lengthy gaps in its ability to track objects in space, however, since the current SBSS satellite is due to reach the end of its service life in the next few years.

Hyten underscored the importance of monitoring objects in space given the increasing drive by other countries to develop the ability to target and disrupt U.S. satellites.

He said the U.S. Air Force stood ready to defend U.S. satellites if they were attacked, and also to deny other countries access to their space assets, if needed.

But he suggested more work was needed in that area, given efforts by other countries to expand their own anti-satellite capabilities.

"I think we're in a very good place in 2014, but whether we're in that same place in 2024 is what I'm talking about," he told reporters after his speech.

One key concern, Hyten said, was the possibility that other countries could create massive amounts of debris in space if they targeted a satellite. Such debris could make it impossible for any country to safely operate satellites, he said.

Hyten said he was horrified by China's decision to destroy a defunct satellite in 2007 because it had created thousands of pieces of long-lasting debris.

"That kind of action in space has the ability to ruin space for the entire planet, so we can't go there," he added.

(Reporting by Andrea Shalal. Editing by Andre Grenon)