TacSat-3 卫星 (Tactical Satellite-3) 最完整的介绍.doc

TacSat-3 (Tactical Satellite-3)TacSat-3 is a follow-up US minisatellite technology demonstration mission within the ORS (Operational Responsive Space) program of DoD, representing a partnership between three military service branches. The partners include NRL (Naval Research Laboratory), AFRL (Air Force Research Laboratory), DARPA (Defense Advanced Research Projects Agency), the Army Space and Missile Defense Center, and the USAF Space and Missile Systems Center. AFRL is leading the TacSat-3 team- serving as the project integrator. The TacSat-3 mission was selected for specific capabilities to meet user needs, and to demonstrate those capabilities within cost and schedule constraints.The overall objectives are to demonstrate a responsive system, namely the operation of three payloads in space: the ARTEMIS hyperspectral imager (HSI), the Ocean Data Telemetry Microsatellite Link (ODTML), the SPA (Spacecraft Plug-n-play Avionics) package - and to provide the observation data in a timely manner. 1) 2) 3) 4) 5) 6) 7) 8)ORS (Operational Responsive Space) - some background: ORS is a DoD-sponsored program and joint initiative managed by OFT (Office of Force Transformation) which started in 2002. All four services are involved in developing the concept and participating in the experimentation. The US. Air Force is leading the effort. OFT is seeking to develop new revolutionary operational concepts and technologies for the conduct of military operations. The overall objective is to develop spacecraft and payloads that can be manufactured and put into space faster then conventional systems, making them available to operational commanders who can task them based on specific needs. ORS principles are based on affordable concepts in flexible and integrated architectures - implying a networking capability to an existing infrastructure in the ground segment. 9) 10) 11)This vision led to an initial approach involving a series of smallsats named TacSat (Tactical Satellite). The TacSat-1 definition started in May of 2003 with the goal to select key elements needed for a deployable ORS experimentation.At the core of the TacSat experiments is the guiding principle of operational experimentation that forces the S&T/R&D (Science & Technology / Research & Development) and the operational communities together to effectively and rapidly channel promising new technologies into new capabilities and ConOps (Concept of Operations).The need for a standardized spacecraft bus has been identified as necessary for an ORS system. Hence, the OFT and AFRL have undertaken a four phase initiative to develop and test bus standards and then transition them for acquisition. The standardization effort involves a fairly broad base, multiple government laboratories, academia and industry MIT/LL, AFRL, NRL, JHU/APL, SMC (Space and Missile systems Command), and many industry as well as university participants as illustrated in Figure 1.Figure 1: Overview of standard bus phases 1 through 4 on the ORS scheme (image credit: JHU/APL) Spacecraft: TacSat-3 is a minisatellite using a standardized modular bus designed and built by Swales Aerospace of Beltsville, MD (contract award in early June 2006). The bus is referred to as ORSMB (Operationally Responsive Space Modular Bus). A major objective is to provide an implementation of bus standards with priority on demonstrating avionics standards - to fit into a network of space assets. The goal is to move toward an adaptable modular bus development process that leverages plug-and-play standards and interfaces and incorporates the latest bus component technologies, supporting multiple payloads and orbital mission profiles. The modular bus development process must address the entire production chain: rapid design, fabrication, integration and test that mix and match off-the-shelf, low-cost proven bus components to meet a variety of payload and orbital mission requirements. A requirement calls for a demonstration of the common plug-and-play electrical and software interfaces between bus components and between the bus and payload.The spacecraft is 3-axis stabilized. The spacecraft mass is 400 kg. The spacecraft design life is one year, the goal is to obtain 3 years of operations.Note: In the spring of 2007, Swales Aerospace of Beltsville, MD (an employee-owned company) was purchased by Alliant Techsystems Inc. (ATK) with corporate headquarters in Edina, Minnesota. Hence, former Swales Aerospace is now known as ATK Spacecraft Systems and Services of Beltsville, MD.Figure 2: Photo of the TacSat-3 bus during integration (image credit: AFRL)Figure 3: Artists rendition of the TacSat-3 spacecraft (image credit: AFRL)Figure 4: Overview of modular bus development scheme (image credit: AFRL)System overview: The TacSat-3 system configuration is illustrated in Figure 5. It consists of the ARTEMIS sensor (instrument), an ARTEMIS Sensor Processor, a CDL (Common Data Link) communications package, a SCP (Satellite Communications Package) experiment, the SAE (Satellite Avionics Experiment), and a spacecraft bus. The overall system includes a CDL ground station, a fielded warfighter, a TGS (Tactical Ground Station), and the AFSCN (Air Force Satellite Control Network).CDL is the DoD standard wideband communications waveform for ISR (Intelligence Surveillance & Reconnaissance) in airborne platforms (the CDL manufacturer is L-3 Communications, Salt Lake City, UT). A CDL system in space brings tactical ISR data directly into existing theater ground stations, allowing for responsive tasking and collection. Utilizing CDL in space provides the benefit of using the existing in-theater CDL ground infrastructure for tactical communications. CDL is a full-duplex, jam resistant spread spectrum, point-to-point digital link. The uplink operates at 200 kbit/s - and possibly up to 45 Mbit/s. The downlink can operate at 10.71 -45 Mbit/s, 137 Mbit/s, or 274 Mbit/s. The CDL program establishes data link standards and specifications identifying compatibility and interoperability requirements between collection platforms and surface terminals across user organizations. 12)Figure 5: System diagram of TacSat-3 (image credit: AFRL)The prime functions of the ARTEMIS Sensor Processor (SP), a stand-alone version from the ARTEMIS sensor, is to provide the control functions of the sensor, power switching, collecting state of health data from ARTEMIS, and storing ARTEMIS source data. Additionally, a fundamental capability of the SP is to autonomously process data cubes from ARTEMIS and produce tactically relevant data for dissemination directly to the fielded warfighter. These products primarily are in the form of text products along with some imagery dependent upon the dissemination method.Figure 6: Illustration of the deployed TacSat-3 spacecraft (image credit: AFRL)Concept of Operations (ConOps): TacSat-3 operations provides two modes of mission support: routine and tactical.- The routine mode is used for collecting HSI (Hyperspectral Imaging) data outside of the assigned theater of operation.- The tactical mode is reserved for anytime the spacecraft can collect over an assigned theater of operation.The tactical mode is driven by one requirement: to demonstrate responsive delivery of decision-quality information to operational and tactical commanders by enabling tactical tasking and data delivery. The delivery latency of the decision-quality information must be less than 30 minutes at a maximum with a goal of less than 10 minutes.RF communications: The second generation CDL (Common Data Link) provides data rates of up to 274 Mbit/s (downlink and uplink in X-band) - in addition to lower data rates for potential ROVER (Remote Operated Video Enhanced Receiver) connectivity. The spacecraft is monitored and controlled by a mission operations center located at Kirtland AFB, NM. The TT&C function is provided in S-band.SCP (Satellite Communications Payload) is an additional transmission link provided by ONR (Office of Naval Research). The objective of SCP is to provide a UHF link for the ODTML (Ocean Data Telemetry MicroSat Link) services and to function as an internal S&F (Store & Forward) subsystem. The downlink of tactical data products via UHF services is considered as more user-friendly since a far greater number of fielded UHF receivers are available in the ground segment than CDL ground stations. 13)Launch: The TacSat-3 spacecraft was launched on May 19, 2009 on a Minotaur-1 vehicle of OSC (Orbital Sciences Corporation) from the commercial MARS (Mid-Atlantic Regional Spaceport) facility at Wallops Island, VA, USA. 14)Secondary payloads on this flight were the CubeSats: PharmaSat-1 (5 kg) a nanosat of NASA/ARC, AeroCube-3 of the Aerospace Corporation of El Segundo, CA, HawkSat-1 of the Hawk Institute for Space Sciences, Pocomoke City, MD, and CP-6 (CalPoly-6) of California Polytechnic State University, San Luis Obispo.Orbit: Near-circular LEO, altitude of about 425 km, inclination of about 40, period = 93.6 minutes.Mission status: On April 30, 2012, TacSat-3 reentered Earths atmosphere, nearly three years after its May 2009 launch. TacSat-3 was designed for six months of operation, with a goal of one year. Not only did it outlive its design life, it also surpassed its original mission requirements and goals as an experimental spacecraft, and was successfully transitioned to operational status in 2010. 15)The spacecraft is a pioneer of the emerging Operationally Responsive Space program, which was designed to meet the growing need of U.S. forces for flexible, affordable and responsive satellite systems.Figure 7: Reentry trajectory of TacSat-3 (image credit: The Aerospace Corporation) 16) The SAE (Spacecraft Avionics Experiment) was developed and flown as a secondary experiment on the AFRL TacSat-3 spacecraft as the first on-orbit demonstration of the SPA (Space Plug-and-Play Architecture ) capability. On numerous occasions during SAE development and test, the modular, reconfigurable SPA interface provided significant cost and schedule savings. SAE consisted of a SPA-USB (SPA-U) network with multiple plug-and-play components with the objective of demonstrating as much core avionics and spacecraft operation as possible in a small secondary payload package. To this end, most elements of a GN&C (Guidance, Navigation, and Control) system were incorporated, to include a sun sensor, rate sensor, temperature sensors, and an AC coupled interconnect experiment. SAE also provided operational backups for TacSat-3 to include a Surrey SGR-05 GPS receiver and a backup high speed SPA-S (SPA-SpaceWire) link between the hyperspectral image processor and the C&DH for payload data transfer. SAE used built-in self test functions to verify on-orbit performance autonomously. Both the SPA-U and SPA-S interfaces operated as designed. One of the SPA-U experiments had a SEU (Single Event Upset) detector on board and no SEUs were observed during experiment operations. SPA-S demonstrated data transfers at 75 Mbps rate with no bit errors observed on orbit. SAE was developed for AFRL by the Space Systems Group at Sierra Nevada Corporation. 17) In late February 2012, satellite control authority of TacSat-3 was transferred to the SMC (Space and Missile Systems Center). The SMC has started end-of-life testing prior to disposing of the vehicle. The reason: TacSat-3 has continued to lose altitude. The satellite will eventually fall from orbit and burn up in Earths atmosphere. 18)- The satellite demonstrated a high level of flexibility by supporting both combat operations and humanitarian missions worldwide, and its extended life span was attributed to the outstanding abilities of its manufacturer as well as the operators who kept it flying. The satellite assisted also in recovery operations following the devastating Japanese earthquake and subsequent nuclear meltdown of 2011. - Aside from the operational success, the TacSat-3 spacecraft was used to prepare Team 8-Ball for the arrival of ORS (Operationally Responsive Space-1), a USAF minisatellite of TacSat-3 heritage (launched on June 30, 2011) which began to provide operating services in 2011 (Ref. 18). The TacSat-3 mission is operating nominally in 2011 - marking its two-year anniversary on-orbit in May 2011. The spacecraft has far exceeded expectations in both its superior imaging performance and in its operational service life. The ARTEMIS imager continues to provide valuable information to combatant commanders. 19) 20)- Operations of the satellite have progressed to the point where the payload is generating about 100 hypercube data products each month. The time needed to compare the hypercubes to a catalog of known materials and provide useful information for troops on the ground has been reduced dramatically since the beginning of the program. A data product that used to take a full day to exploit can now be processed in a few hours. Today, all of the processing and analysis of the ARTEMIS raw data is done in the United States and then the information is relayed to the troops elsewhere in the world. Raytheon engineers are working on a software upgrade for the spacecraft that will allow it to do a limited amount of automated exploitation and send the virtual “data chip” directly to the users in the field. 21) The TacSat-3 mission is operating nominally in the early fall of 2010. After the handover of the experimental TacSat-3 mission from AFRL/SMC to the Air Force Space Command at Peterson AFB (June 2010), the AFRL development team reflected on the various aspects of the TacSat-3 mission in the summer of 2010. Key insights into hyperspectral imaging capabilities were obtained in the mission so far. 22) 23) 24)Lessons learned from the development, I&T (Integration & Test phase), and experimental operations of TacSat-3 and ARTEMIS will be carried forth to future AFRL flight experiments. As technology advances, it demonstrates the utility of small spacecraft to make meaningful impacts in support of national defense.Figure 8: Sample of an ARTEMIS image of the Kilauea volcano, Hawaii, modified for public release using three of 400+ spectral bands to create a rendering from detailed spectral data (image credit: AFRL) In May 2010, TacSat-3 completed its one-year experimental mission. On June 12, 2010, TacSat-3 transitioned from an experimental demonstration to an operational asset when spacecraft control authority officially was transferred from AFRL/SMC to the Air Force Space Command at Peterson AFB, CO, USA. The mission achieved a number of milestones such as proving the capability of transmitting processed data to a ground station within 10 minutes of call up; also, use of PnP technology in the avionics experiment, downloading information obtained from ocean-based buoys to a ground station with the ONR-sponsored Satellite Communications Package (ODTML). The small satellite has been able to assist with the earthquake relief efforts in Haiti and Chile and now the team looks forward to its new role in the operational arena. 25) 26) 27) 28) 29) As of March 2010, TacSat-3 so far has collected some 1,600 hyperspectral images and has been working its way through 90 different experiments. Data from the satellite have been used in operational missions. In April 2010, the Pentagon will decide whether to hand the spacecraft over to the combatant commands to use full-time in May or June 2010. The performance of the system has been verified. All systems are go from an engineering perspective. 30) During the first month after launch, the program has accomplished early on-orbit checkout and anticipates completing calibration procedures by the end of June 2009. The following items represent some accomplishments during the first month in orbit: 31)- Within two hours after launch, the spacecrafts solar arrays initiated power to operate key components, and controllers operated the satellite- About 48 hours following liftoff, program officials verified the functionality of the primary payload, the ARTEMIS (Advanced Responsive Tactically-Effective Military Imaging Spectrometer), and sensor processing.- During the first 2.5 days of the mission, the ARTEMIS sensor produced a high-resolution image, the satellite successfully communicated to a ground station via a high-bandwidth data link and operators discovered TacSat-3 had 50% more power than originally planned for due to the solar panels efficiency.- Following cool down in the initial week, the ARTEMIS also conducted a hyperspectral image collect.- In week two after launch, controllers initiated ARTEMIS focus operations and validated the spacecrafts autonomous software.- Between week 2 and 3 after liftoff, the satellite proved its tactical mode by collecting and processing hyperspectral imagery, downloaded a tactical product within a single, 10-minute pass, and validated that the secondary payloads, the Office of Naval Research Space Communications Package and the AFRL Space Avionics Experiment, were performing as required.Sensor complement: (ARTEMIS, ODTML, SAE)Building on the experiences with TacSat-1 and -2, TacSat-3 is the first spacecraft of the series to have gone through a formal payload selection process with AFSPC (Air Force Space Command) and Coordinating Commands (COCOMs) and Services.ARTEMIS (Advanced Responsive Tactically Effective Military Imaging Spectrometer):ARTEMIS is a hyperspectral imager (HSI), funded by AFRL with additional funding by the US Army, designed and developed at Raytheon Space and Airborne Systems of El Segundo, CA, using COTS components extensively (ARTEMIS contract award in 2005). There is also a collaboration on the imaging spectrometer from NASA/JPL. The main objectives are: To demonstrate tactically significant hyperspectral imagery coll