USSTRATCOM Space Control and Space Surveillance
USSTRATCOM's space control mission includes: surveillance of space, protection of US and friendly space systems, prevention of an adversary's ability to use space systems and services for purposes hostile to US national security interests, and direct support to battle management, command, control, communications, and intelligence. The space control mission is conducted by USSTRATCOM's Joint Functional Component Command for Space (JFCC SPACE).
JFCC SPACE, through its Joint Space Operations Center (JSpOC), detects, tracks, and identifies all artificial objects in Earth orbit. The JSpOC is a synergistic command and control weapon system focused on planning and executing USSTRATCOM's JFCC SPACE mission. Its purpose is to provide a focal point for the operational employment of worldwide joint space forces, and enable the Commander, JFCC SPACE (CDR JFCC SPACE) to integrate space power into global military operations.
The JSpOC is composed of six core divisions: Strategy Division (SRD), Combat Plans Division (CPD), Combat Operations Divison (COD), United Space Vault (USV), Intelligence, Surveillance and Reconnaissance Division (ISRD), and Operations Support Division (OSD).
- SRD develops comprehensive space strategy that directly supports CDR JFCC SPACE and Combatant Commanders by integrating space effects, timing and tempo into the commander's campaign objectives.
- CPD produces the products that are used to plan, direct, and execute JFCC SPACE forces to produce optimal effects in support of the Commanders' intent, priorities, and objectives.
- COD conducts command and control over the execution phase of operations and provides information on tasking responses to CDR JFCC SPACE, the other JSpOC divisions, upper command echelons, and theater space personnel for their space situational awareness.
- USV conducts various classified and unclassified Defensive Space Control, Offensive Space Control, and Space Situational Awareness (SSA) missions.
- ISRD is integrated into all phases of the operational cycle, providing pertinent space intelligence information to the other divisions in support of the strategy, planning and operations monitoring efforts.
- OSD provides training, standardization, evaluation and system integration support.
The JSpOC maintains the catalog of all artificial Earth-orbiting objects, charts preset positions for orbital flight safety, and predicts objects reentering the Earth's atmosphere. Since the launch of Sputnik in 1957, over 39,000 man-made objects have been catalogued, many of which have since re-entered the atmosphere. Currently, the JSpOC tracks more than 16,000 objects orbiting Earth. About 5 percent of those being tracked are functioning payloads or satellites, 8 percent are rocket bodies, and about 87 percent are debris and/or inactive satellites.
JSpOC tasks the Space Surveillance Network (SSN), a worldwide network of 30 space surveillance sensors (radar and optical telescopes, both military and civilian) to observe the objects. The crews match sensor observations to the orbiting objects, catalog, and update the position and velocity of each one. These updates form the Satellite Catalog, a comprehensive listing of the numbers, types, and orbits of all trackable objects in space.
The JSpOC uses the SSN to take between 380,000 to 420,000 observations each day. The SSN sensors are categorized as dedicated (those with the primary mission of performing space surveillance), contributing, or collateral sensors (those with a primary mission other than space surveillance). SSN Sensorsuse a "predictive" technique to monitor space objects, i.e. , it spot checks them rather than tracking them continually. This technique is used because of the limits of the SSN (number of sensors, geographic distribution, capability, and availability). Below is a brief description of each type of sensor:
- Phased-array radars can maintain tracks on multiple satellites simultaneously and scan large areas of space in a fraction of a second. These radars have no moving mechanical parts. Because the radar energy is steered electronically, there is no limit the speed of the radar scan. A transmit antenna transmits radar energy into space in the shape of a large fan. When a satellite intersects the fan, energy is reflected back to the detection antenna, where the location of the satellite is computed. Two examples of these radars include Cavalier AFS in North Dakota and Eglin AFB in Florida.
- Conventional radars use moveable tracking antennas or fixed detection and tracking antennas. A tracking antenna steers a narrow beam of energy toward a satellite and uses the returned energy to compute the location of the satellite and to follow the satellite's motion to collect more data. These radars include the Altair complex at the Reagan Test Site in the Kwajalein Atoll and the Haystack Millstone facility at the Massachusetts Institute of Technology Lincoln Laboratory.
- Electro-Optical Sensors consist of telescopes linked to video cameras and computers. The video cameras feed their space pictures into a nearby computer that drives a display scope. The image is transposed into electrical impulses and recorded on magnetic tape. This is the same process used by video cameras. Thus, the image can be recorded and analyzed in real-time. Ground-Based Electro-Optical Deep Space Surveillance (GEODSS) sites assigned to Air Force Space Command (AFSPC) play a vital role in tracking deep space objects. Between 4,200 and 4,400 objects, including geostationary communications satellites, are in deep space orbits more than 22,500 miles from Earth.
- Space Based Sensors have the ability to detect debris, spacecraft, or other distant space objects without interference from weather, atmosphere, or time of day. Space based sensors use optical or infrared sensors which either scan, or quickly focus between targets without having to expend time and fuel to reposition the entire spacecraft.
On a routine basis, the JSpOC conducts conjunction analysis for all active spacecraft. During human space flight launches, the center computes possible close approaches of other orbiting objects with the flight path of the Soyuz and the International Space Station (ISS). The JSpOC constructs a theoretical box around a high interest object, (e.g. the ISS) and projects the flight path several days in advance of the launch. If any of the catalogued objects intersect this theoretical box, the JSpOC forwards the analysis to NASA. NASA makes the determination whether or not to change the flight path of the ISS. NASA offers to the general public, on its website, the opportunity to track various satellites.
The 614th Air and Space Operations Center, Detachment 1 (614 AOC/Det 1) provides the site and personnel to provide a geographically separate backup to JSpOC's SSA Operations. The 614 AOC/Det 1 will take over SSA operations in the event the space control mission at the JSpOC could not function. This capability is routinely exercised.
Re-entry Assessment describes the operational procedures by which USSTRATCOM predicts the time and location of atmospheric reentry of decaying space objects. Current capabilities allow the ability to predict within a 30-minute, 6,000-mile window when and where a particular object will re-enter the Earth's upper atmosphere.
Objects are tracked throughout their orbital life, with the results posted in the Satellite Catalog. When an object appears to be re-entering within seven days, orbital analysts in the JSpOC will increase sensor tasking (monitoring) and begin to project a refined re-entry time and location. Messages indicating the calculated re-entry time and location are transmitted to forward users and customers at the 4, 3, 2, and 1-day points. Starting at the 24-hour point, the object is continuously refined, with processing at the 12, 6 and 2-hour points. Again, ground traces and messages are transmitted to SSN sensors and posted on public websites. The object is monitored throughout re-entry.
It is virtually impossible to precisely predict where and when space debris will impact due to limitations in the tracking system as well as perturbation factors that can influence reentering objects. Most of USSTRATCOM's space-tracking radars are located in the Northern Hemisphere, making continuous orbit coverage impossible. Consequently, a returning satellite could be outside sensor coverage for several hours.
Also, perturbation factors acting on an object's orbit could include variations in the gravitational field of the landmass and ocean areas, solar radiation pressure, and atmospheric drag. Objects re-entering may skip off the Earth's atmosphere, much as a stone skipped across a pond, causing it to impact much further away than originally forecast.
USSTRATCOM will verify that an object has re-entered by using a process of "No Show" sensor reports verifying the object is no longer in orbit. Once it is determined not to be in orbit, sensor tasking ends and the object is deleted from the "Active" tracking mission of the surveillance network.
The chances of someone being struck by a re-entering object are slight. The great majority of objects that re-enter disintegrate due to the intense heat created by interaction with the Earth's atmosphere. Only a small percentage of objects ever re-enter over land since water comprises 75 percent of the Earth's surface. Additionally, only about 25 percent of the Earth's landmass is actually inhabited. If the object is forecast to make landfall in North America or Hawaii, the JSpOC will notify the Federal Emergency Management Agency and/or Public Safety Canada.
USSTRATCOM maintains historical orbital data on objects even after they have re-entered the Earth's atmosphere. Unless an object is actually found and returned to NASA or any other agency, USSTRATCOM would have no knowledge of objects that have survived re-entry.
Current as of Dec 2012