Space situational awareness (SSA) is the foundational element of space security, and it entails keeping track of all natural and artificial space objects, energy and particle fluxes and understanding how the space picture is changing over time. SSA is a system of systems dealing with space surveillance, space weather and NEOs.
Comprehensive SSA requires a networked system of radars and electro-optical sensors. Low altitude debris is usually observed by radar ground stations while high altitude debris is observed by optical ground stations. Recently the trend is to use space-based sensors to provide timely detection, collection, identification and tracking of man-made space objects from deep space to LEO orbits.
Operationally Responsive Space-5 (ORS-5) satellite was launched aboard the Orbital ATK Minotaur IV space launch vehicle (SLV) from Cape Canaveral Air Force Station in August 2017. The ORS-5 spacecraft is placed in low inclination orbit approximately 599km above the earth and is used to track other satellites and space debris in geosynchronous orbit (GSO).
The ORS-5 is a single satellite constellation with a primary mission to provide space situational awareness of the geosynchronous orbit belt for Combatant Commanders’ urgent needs, according to Brig. Gen. Wayne Monteith. ORS-5 is like a telescope wrapped in a satellite that will aim up to seek threats from LEO to GEO using cameras and spectrometer sensors.
Also known as SensorSat, ORS-5 is designed to scan for other satellites and debris to aid the U.S. military’s tracking of objects in geosynchronous orbit for a minimum of three years and possibly longer if its on board sensor and spacecraft systems continue functioning in a useful and productive manner.
The Minotaur IV is a five stage rocket comprised of three stages of a decommissioned Cold War-era Peacekeeper Intercontinental Ballistic Missile (ICBM) that has been modified to add two additional Orbital ATK Orion 38 solid rocket motors for the upper stages.
Space Based Sensors
(SBS) consist of a space segment, primarily consisting of constellation of radar satellites and a ground segment including networked ground stations to control the satellites. SBS having the ability to track space objects from space, offer advantages over ground based systems since they are not affected by weather or atmosphere. This leads to improved sensor sensitivity and allows for the detection of faint objects including microsatellites and space debris. This in turn increases the probability of detection of collision event by improving the timeliness of detection for maneuver. Thus Space based sensors provide timely detection, collection, identification and tracking of man-made space objects from deep space to low-earth orbits.
Operationally Responsive Space-5
The ORS-5 (Operationally Responsive Space-5) is a new space surveillance satellite that has been developed by the Operationally Responsive Space (ORS) Office for the US Air Force (USAF).
It is intended to provide more cost-efficient geosynchronous space situational awareness (SSA) compared to bigger and more complex satellites.
The overall objectives of the ORS-5 program are, in priority order:
- Demonstrate technologies that could prove “good enough” for geosynchronous SSA
- Create risk reduction opportunities to a future program of record
- Develop and demonstrate ORS enablers and principles
ORS-5 development details
The ORS-5 programme is envisioned to demonstrate the cost-efficient launch capability of small satellite and autonomous operations using the Multi-Mission Space Operations Centre’s (MMSOC) current ground system infrastructure. The Massachusetts Institute of Technology’s (MIT) Lincoln Laboratory is the prime contractor for the ORS-5 satellite programme, which required an investment of roughly $87.5m.
Design and payload of ORS-5
The satellite’s highly integrated platform incorporates vehicle components and actuators around the stray light baffle, lens assembly and camera system. The spacecraft has a length of 1.5m and a weight of approximately 113kg.
ORS-5’s satellite system has a designed lifespan of three years and combines time delay integration techniques with optimised flight geometry to ensure a continuous imaging of the GSO.
The structural panels of the satellite bus, sensor optics, stray light baffle, charge coupled device (CCD) mount / camera assembly and camera radiator assembly were designed by the MIT Lincoln Laboratory. The spacecraft’s onboard imaging system comprises a CCD imager, camera electronics, a lens compartment and a lightweight baffle.
ORS-5’s onboard systems are powered by a combination of batteries and solar arrays.
Ground control station
The ORS-5 satellite is operated by the Air Force Space Command’s 50th Space Wing at Schriever Air Force Base (AFB) in Colorado Springs, Colorado.
The satellite will transmit the space surveillance data to the United States Strategic Command via the Joint Space Operations Center (JSpOC).
ORS-5’s command and control is handled through the Air Force Satellite Control Network (AFSCN), while the centres at Guam and Diego Garcia serve as the primary and back-up ground stations.