By Steve Brady
21st Space Wing Public Affairs
PETERSON AIR FORCE BASE, Colo. — The Air Force relies on Airmen around the globe to monitor space, and maintain the Air Force presence in space.
“Space superiority isn’t a birthright. It must be secured and preserved,” Lt. Gen. David Buck, former 14th Air Force commander, said at the Air Force Research Laboratory space situational awareness conference Sept. 18, 2017. “This requires constant vigilance, strong partnerships and active participation,” he said. “To keep pace in this contested, degraded and operationally-limited environment, real-time orbit determination, change detection and custody are foundational.”
Part of keeping pace in that environment includes tracking the approximately 1,800 active satellites and myriad other man-made objects orbiting the Earth — a substantial task the Airmen at the 18th Space Control Squadron do not take lightly.
The 18th SPCS is one of the 21st Space Wing’s many geographically separated units, carrying out part of the Wing’s space surveillance mission.
“We deliver foundational Space Situational Awareness to assure global freedom of action in space,” said Lt. Col. Mia Walsh, 18th SPCS commander. Foundational SSA includes maintaining the space catalog by tracking more than 23,000 man-made objects in orbit and detecting activities in space.
The 18th Space Control Squadron maintains the space catalog. This data allows the 18th SPCS to provide a wide range of spaceflight safety services to the Department of Defense, launch agencies, satellite operators, and interagency and Allied partners. The services include launch collision avoidance, launch support, on-orbit conjunction assessment and collision avoidance, end-of-life disposal, de-orbit support, and re-entry assessment.
One of the many objects they have been tracking is Tiangong-1, a Chinese space station launched in 2011. The space station is now in a decaying orbit, and is estimated to return to Earth in April.
“We are tracking the Tiangong-1, as well as 23,000 other objects in space, to ensure the safe and responsible use of space,” Walsh said.
The thought of such a large object – approximately 18,000 pounds – re-entering Earth’s atmosphere, has caused concern in some circles.
“Depending on the size of the object, it may completely burn up in the atmosphere or break up into smaller pieces that do not survive re-entry. Infrequently, pieces re-enter the atmosphere intact, but 18th SPCS does not track re-entries through earth impact,” Walsh said.
Predicting re-entry can fluctuate based on the speed of the object and atmospheric drag.
“We provide a series of predictions of when an object will re-enter the earth’s atmosphere, approximately 10 kilometers above the earth’s surface. Predictions begin as soon as 60 days prior to re-entry, and are provided more frequently within four days of re-entry,” she said. “As the re-entry date approaches, the predictions become more accurate, however, they can fluctuate dramatically as the speed of the object and atmospheric drag increase and affect the object’s re-entry path.”
Even after re-entry, objects remain in the space catalog. The 18th SPCS does not remove objects from the space catalog, but will record its decay date – the date that it re-entered the atmosphere – in the catalog.
Tracking objects in the space domain is vital to every-day life, as well as military operations.
“Space is foundational to military operations and the American way of life,” she said. “Space capabilities and the technologies they support are woven into the fabric of everyday life through information and conveniences that we consider routine; weather reports, ATMs, maps on your phone, cable television – all of this is enabled by satellites in space, which rely on a safe domain to provide uninterrupted services. The space domain is also vital to national security; space capabilities allow military commanders to see the battlespace with clarity, strike with precision, navigate with accuracy, communicate with certainty, and operate with assurance over global distances.”
While keeping track of all the objects in orbit is a large task, it is vital to the safe and responsible use of space.
“All nations benefit from a safe, stable, sustainable, and secure space domain,” she said, “so it is imperative that all space actors operate responsibly to preserve the space environment to ensure free access for peaceful purposes.”