USA-273, also known as SBIRS GEO-3, is a

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

military satellite A military satellite is an artificial satellite used for a military purpose. The most common missions are intelligence gathering, navigation and military communications. The first military satellites were photographic reconnaissance missions. So ...

and part of the

Space-Based Infrared System The Space-Based Infrared System (SBIRS) is a United States Space Force system intended to meet the United States' Department of Defense infrared space surveillance needs through the first two to three decades of the 21st century. The SBIRS prog ...

(SBIRS).

Overview of SBIRS

The SBIRS satellites are a replacement for the

Defense Support Program The Defense Support Program (DSP) is a program of the United States Space Force that operated the reconnaissance satellites which form the principal component of the ''Satellite Early Warning System'' used by the United States. DSP satellite ...

(DSP) early warning system. They are intended to detect

ballistic missile A ballistic missile is a type of missile that uses projectile motion to deliver warheads on a target. These weapons are guided only during relatively brief periods—most of the flight is unpowered. Short-range ballistic missiles stay within the ...

launches, as well as various other events in the

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

spectrum, including

nuclear explosion A nuclear explosion is an explosion that occurs as a result of the rapid release of energy from a high-speed nuclear reaction. The driving reaction may be nuclear fission or nuclear fusion or a multi-stage cascading combination of the two, tho ...

aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engine ...

flights, space object entries and reentries,

wildfire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identi ...

s and spacecraft launches. The mission of SBIRS states that "The SBIRS program was designed to provide a seamless operational transition from DSP to SBIRS and meet jointly-defined requirements of the defense and intelligence communities in support of the missile early warning, missile defense, battlespace awareness and technical intelligence mission areas."

Satellite description

SBIRS-GEO 3 was manufactured by

Lockheed Martin Space Lockheed Martin Space is one of the four major business divisions of Lockheed Martin. It has its headquarters in Littleton, Colorado, with additional sites in Valley Forge, Pennsylvania; Sunnyvale, California; Santa Cruz, California; Huntsvill ...

and was built upon the A2100M, a militarised, radiation hardened

satellite bus A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are opposed to specially produced satellites. Bus- ...

that provides power, attitude control, command and control and a communications subsystem with five separate mission data downlinks to meet mission requirements, including system survivability and endurability requirements.

SBIRS sensors

The SBIRS

sensors A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon. In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ...

are designed to provide greater flexibility and sensitivity than the DSP

sensor, in addition to detecting short-wave and mid-wave infrared signals, allowing SBIRS to perform a broader set of missions. These enhanced capabilities result in improved prediction accuracy for global strategic and tactical warfighters. Improvements to the ground system processing software are on-going, resulting in increased event message accuracy and reduced manpower requirements for support and operations of the DSP and SBIRS. The infrared payload consists of two sensors; a scanner and a step-starer. The scanning sensor continuously scans the Earth to provide 24-7 global strategic missile warning capability. Data from the scanner also contributes to theater and intelligence missions. The step-staring sensor provides coverage for theater missions and intelligence areas of interest. On-board signal processing allows detected events to be transmitted to the ground, but the raw, unprocessed data gathered by the infrared sensors are down-linked as well, so the same

radiometric Radiometry is a set of techniques for measuring electromagnetic radiation, including visible light. Radiometric techniques in optics characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which ch ...

scene observed in space will be available for ground-based processing.

Launch

It was launched on 21 January 2017 from Cape Canaveral (CCAFS), atop an

Atlas V Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Mart ...

launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload ( spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and ...

References

External links

SBIRS GEO-1, -2, -3, -4 at Gunter's Space Page
{{Orbital launches in 2017 Spacecraft launched in 2017 Reconnaissance satellites of the United States USA satellites Early warning satellites 2017 in the United States