TacSat-3
Encyclopedia
TacSat-3 is the third in a series of U.S. military reconnaissance satellites. It was assembled in an Air Force Research Laboratory
Space Vehicles Directorate facility at Kirtland Air Force Base
, New Mexico. The TacSat satellites are all designed to demonstrate the ability to provide real-time data collected from space to combatant commanders in the field. TacSat-3 includes three distinct payloads: the Advanced Responsive Tactically Effective Military Imaging Spectrometer (ARTEMIS
) hyperspectral imager, the Ocean Data Telemetry Microsatellite Link and the Space Avionics Experiment.
. The payload consists of a two mirror Ritchey–Chrétien telescope plus correction optics, with a focus
device incorporated in the secondary mirror unit, and with a slit Offner spectrometer. The spectrometer uses the ARTEMIS hyperspectral imaging sensor (HSI), which is a single HgCdTe Focal Plane Array covering the entire V/NIR/SWIR spectrum from 400 nm to 2500 nm at a uniform resolution of 5 nm. ARTEMIS measures first the spectral information at each point on the ground in 400 spectral channels. HSI data cubes obtained by ARTEMIS are then handled by a reprogrammable digital signal processor with 16 GB data storage capability to generate on-board products and for in-theater downlink. TacSat-3's main focus is land-based HSI. According to Peter Wegner from the Operationally Responsive Space Office
, TacSat-3 cost US$90 million
rocket. However, in March 2009 it was announced that the component issues had been resolved and a launch date was set for May 5, 2009. The May 5 launch attempt was scrubbed and a new launch date was set for May 19, with a backup date of May 20. The launch occurred successfully at 23:55 UTC on 19 May, 20 minutes into a launch window running from 23:35 to 03:30 (7:35 PM to 11:30 PM local time) each night.
The first attempt to launch TacSat-3 was made on 6 May, during a window running from 00:00-03:00 UTC (20:00-23:00 local time on 5 May). However, due to thunderstorms and very low ceilings which prevented the surveillance plane from taking off, this launch attempt was scrubbed and the next attempt was scheduled for May 8 during the same window. The May 8th attempt was also scrubbed due to thunderstorms and heavy rain, which once again, prevented the surveillance plane from being able to take off. Another attempt was scheduled for the next day on May 9, again with the same window. Although the weather cooperated better for the May 9th attempt, a launch support equipment problem caused a delay of approximately three hours past the scheduled launch time. This problem was resolved and the countdown resumed. However, with 2 minutes and 16 seconds left on the countdown clock, an unexpected hold was called. Several minutes later, this launch attempt was also scrubbed due to low electrical voltage on the AGC of the Flight Termination System. A new launch date was set for May 19 with May 20 as a backup date.
The spacecraft was successfully launched at 23:55 UTC on May 19, 2009 after a small delay to remove off shore boaters from the exclusion area.
manpack military radio can directly communicate with the satellite in the ultrahigh frequency band. TacSat-3/ARTEMIS observations of the National Mall
and the Kilauea Volcano to support technical validation of the sensor have been released in June 2010. The released images comprise three of the more than 400 spectral bands.
Air Force Research Laboratory
The Air Force Research Laboratory is a scientific research organization operated by the United States Air Force Materiel Command dedicated to leading the discovery, development, and integration of affordable aerospace warfighting technologies; planning and executing the Air Force science and...
Space Vehicles Directorate facility at Kirtland Air Force Base
Kirtland Air Force Base
Kirtland Air Force Base is a United States Air Force base located in the southeast quadrant of the Albuquerque, New Mexico urban area, adjacent to the Albuquerque International Sunport. The base was named for the early Army aviator Col. Roy C. Kirtland...
, New Mexico. The TacSat satellites are all designed to demonstrate the ability to provide real-time data collected from space to combatant commanders in the field. TacSat-3 includes three distinct payloads: the Advanced Responsive Tactically Effective Military Imaging Spectrometer (ARTEMIS
Artemis
Artemis was one of the most widely venerated of the Ancient Greek deities. Her Roman equivalent is Diana. Some scholars believe that the name and indeed the goddess herself was originally pre-Greek. Homer refers to her as Artemis Agrotera, Potnia Theron: "Artemis of the wildland, Mistress of Animals"...
) hyperspectral imager, the Ocean Data Telemetry Microsatellite Link and the Space Avionics Experiment.
Design
TacSat-3 uses a standard satellite bus developed and provided by ATKAlliant Techsystems
Alliant Techsystems Inc., most commonly known by its ticker symbol, ', is one of the largest aerospace and defense companies in the United States with more than 18,000 employees in 22 states, Puerto Rico and internationally, and 2010 revenues in excess of an estimated...
. The payload consists of a two mirror Ritchey–Chrétien telescope plus correction optics, with a focus
Focus (optics)
In geometrical optics, a focus, also called an image point, is the point where light rays originating from a point on the object converge. Although the focus is conceptually a point, physically the focus has a spatial extent, called the blur circle. This non-ideal focusing may be caused by...
device incorporated in the secondary mirror unit, and with a slit Offner spectrometer. The spectrometer uses the ARTEMIS hyperspectral imaging sensor (HSI), which is a single HgCdTe Focal Plane Array covering the entire V/NIR/SWIR spectrum from 400 nm to 2500 nm at a uniform resolution of 5 nm. ARTEMIS measures first the spectral information at each point on the ground in 400 spectral channels. HSI data cubes obtained by ARTEMIS are then handled by a reprogrammable digital signal processor with 16 GB data storage capability to generate on-board products and for in-theater downlink. TacSat-3's main focus is land-based HSI. According to Peter Wegner from the Operationally Responsive Space Office
Operationally Responsive Space Office
The Operationally Responsive Space Office is a joint initiative of several agencies within the United States Department of Defense . The "stand up" of the office took place 2007-05-21 at Kirtland Air Force Base. The first director of the ORS Office is Col. Kevin McLaughlin, who is also commander...
, TacSat-3 cost US$90 million
Launch history
In January 2009 the Air Force announced that a malfunctioning component has postponed the launch date on its MinotaurMinotaur (rocket)
The Minotaur is a family of American solid fuel rockets derived from converted Minuteman and Peacekeeper intercontinental ballistic missiles. They are built by Orbital Sciences Corporation....
rocket. However, in March 2009 it was announced that the component issues had been resolved and a launch date was set for May 5, 2009. The May 5 launch attempt was scrubbed and a new launch date was set for May 19, with a backup date of May 20. The launch occurred successfully at 23:55 UTC on 19 May, 20 minutes into a launch window running from 23:35 to 03:30 (7:35 PM to 11:30 PM local time) each night.
The first attempt to launch TacSat-3 was made on 6 May, during a window running from 00:00-03:00 UTC (20:00-23:00 local time on 5 May). However, due to thunderstorms and very low ceilings which prevented the surveillance plane from taking off, this launch attempt was scrubbed and the next attempt was scheduled for May 8 during the same window. The May 8th attempt was also scrubbed due to thunderstorms and heavy rain, which once again, prevented the surveillance plane from being able to take off. Another attempt was scheduled for the next day on May 9, again with the same window. Although the weather cooperated better for the May 9th attempt, a launch support equipment problem caused a delay of approximately three hours past the scheduled launch time. This problem was resolved and the countdown resumed. However, with 2 minutes and 16 seconds left on the countdown clock, an unexpected hold was called. Several minutes later, this launch attempt was also scrubbed due to low electrical voltage on the AGC of the Flight Termination System. A new launch date was set for May 19 with May 20 as a backup date.
The spacecraft was successfully launched at 23:55 UTC on May 19, 2009 after a small delay to remove off shore boaters from the exclusion area.
Mission
TacSat-3 achieves a HSI ground resolution of 4 meter, which enables it to detect and identify tactical targets. After a successful completion of a one year experimental phase, and the acquisition of more than 2100 images, TacSat-3 was handed over to the Air Force in June 2010 as a full-time operational asset. It is the first hyperspectral satellite with the ability to provide reconnaissance within 10 minutes after passing overhead. Field commanders, using, e.g., a AN/PRC-117FAN/PRC-117F
The AN/PRC-117F Multiband Manpack Radio, or Multiband Multi Mission Radio , is a man-portable, tactical software-defined combat-net radio covering the 30-512 MHz frequency range. The radio is manufactured by Harris Corporation...
manpack military radio can directly communicate with the satellite in the ultrahigh frequency band. TacSat-3/ARTEMIS observations of the National Mall
National Mall
The National Mall is an open-area national park in downtown Washington, D.C., the capital of the United States. The National Mall is a unit of the National Park Service , and is administered by the National Mall and Memorial Parks unit...
and the Kilauea Volcano to support technical validation of the sensor have been released in June 2010. The released images comprise three of the more than 400 spectral bands.
Gallery
External links
- TacSat-3 Information - includes information about ARTEMIS.
- Survey and Analysis of Fore-Optics for Hyperspectral Imaging Systems
- RC Optical Systems 16" f/8.4 Ritchey-Chretien Carbon Fiber Optical Tube: summary of design specifics and close-up of Ritchey-Chretien Secondary Focuser