Chapter 41 Next-generation for Earth Monitoring and Observation – High Definition Imaging and Video of Earth Jakob Lifshits, Jakob LifshitsSearch for more papers by this authorLuke Stras, Luke StrasSearch for more papers by this authorSimon C. O. Grocott, Simon C. O. GrocottSearch for more papers by this authorFreddy M. Pranajaya, Freddy M. PranajayaSearch for more papers by this authorRobert E. Zee, Robert E. ZeeSearch for more papers by this author Jakob Lifshits, Jakob LifshitsSearch for more papers by this authorLuke Stras, Luke StrasSearch for more papers by this authorSimon C. O. Grocott, Simon C. O. GrocottSearch for more papers by this authorFreddy M. Pranajaya, Freddy M. PranajayaSearch for more papers by this authorRobert E. Zee, Robert E. ZeeSearch for more papers by this author Book Editor(s):Shen-En Qian, Shen-En Qian Canadian Space Agency, CanadaSearch for more papers by this author First published: 20 November 2015 https://doi.org/10.1002/9781118945179.ch41 AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onFacebookTwitterLinked InRedditWechat Summary NEMO-HD (Nanosatellite for Earth Observation and Monitoring - High Definition) is a small spacecraft designed and built by the Space Flight Laboratory (SFL) for the Slovenian Centre of Excellence for Space Sciences and Technologies (SPACE-SI). This spacecraft performs a multitude of roles, from acting as an experimental test bed for the development of novel control and image processing algorithms, to providing a commercial service offering rapid response for monitoring crops and the effects of environmental disasters. Data from NEMO-HD is also used to augment terrestrial mapping services. Weighing in at 65 kg, this light-weight spacecraft builds on the experience acquired during the design and construction of SFL's other optical remote sensing missions to deliver a new level of performance in a very small package. NEMO-HD is designed to provide moderate-to high-resolution Earth imagery in a number of bands, including pan, blue, green, red and near infrared channels. In addition, NEMO-HD carries two high-definition video channels, each providing real-time video at 25 frames per second. The video channels are co-boresighted with the still imagery channels. This allows for a unique real-time imaging mode, in which an operator views the real-time video feed and commands the spacecraft to image a target of interest. Optical Payloads for Space Missions RelatedInformation

The Nanosatellite for Earth Monitoring and Observation Aerosol Monitor (NEMO-AM) is a high performance spacecraft in the final stages of development at the Space Flight Laboratory (SFL). The mission is funded by the Indian Space Research Organization (ISRO) with the purpose of detecting atmospheric aerosols in multiple bands over particular geographical areas with sub-degree accuracy. The satellite design leverages the lessons learned on previous SFL missions and, in part, is developed around the Generic Nanosatellite Bus concept, where a multipurpose and adaptable satellite bus is designed to work with a wide range of payloads with little or no modification. Consequently, many of the hardware components on NEMO-AM are inherited from the Generic Nanosatellite Bus and likewise boast flight heritage. The satellite also employs new technologies facilitated by commercial off-the-shelf hardware. This enabled shorter design cycles, but allowed those periods to be focused more on mission specific goals. The satellite bus envelopes a volume of 20 cm x 20 cm x 40 cm (main body) and has a mass of 16.1 kg with a power throughput capability of 80W. NEMO-AM will fly a standard suite of Attitude and Orbit Control Subsystem components found on the Generic Nanosatellite Bus, a GPS receiver, communication antennas (S-band for uplink and downlink), onboard computers for task management, a power distribution network including batteries and solar cells, and a multi-spectral imager to capture aerosol concentration measurements.

Defence Research and Development Canada (DRDC) and the Canadian Space Agency (CSA) are jointly working to place a microsatellite, equipped with a small optical telescope, on orbit to detect and track both "deep-space" earth orbiting objects (orbital altitudes > 5000 km), and inner-earth orbit (IEO) asteroids. The satellite will be named the Near Earth Orbit Surveillance Satellite (NEOSSat), is baselined for launch in 4(th) Q 2008, and will be equipped with a 15cm diameter telescope capable of detecting 19.5(th) magnitude stars over a 100s integration. Other important design requirements of this telescope include the ability to observe to within 45 degrees of the sun (to better detect IEO asteroids) and the ability to observe to within 20 degrees of the anti-sun direction and remain power-positive. The mission is expected to cost $11 M CDN (launch costs included, but operating and ground-station costs excluded).The scientific aims of the NEOSSat mission will be described and the results of the NEOSSat Phase-A will be presented. Test observations have been conducted using the MOST ("Microvariability and Oscillations of STars") microsatellite, the inspiration for NEOSSat, and the results of these observations will be shown here; these tests validate both the general concept of using a microsatellite for these types of observations, as well as the expected performance.

The MOST (Microvariability and Oscillations of STars) astronomy mission under the Canadian Space Agency’s Small Payloads Program is Canada’s first space science microsatellite and is scheduled to launch in June 2003. The MOST science team will use the satellite to conduct long-duration stellar photometry observations in space. The primary science objectives include: measuring light intensity oscillations in solar type stars; determining the age of nearby “metal-poor sub-dwarf” stars, which will in turn allow a lower limit to be set on the age of the Universe; and detecting the first reflected light from orbiting exoplanets and using it to determine the composition of their atmospheres. To make these measurements, MOST incorporates into a microsatellite design a small (15 cm aperture), high-photometric-precision optical telescope and a high performance attitude control system that is revolutionary in its pointing accuracy for a microsatellite. A key hurdle that the MOST mission had to overcome was that of access to space. MOST as initially conceived was designed to launch as a secondary payload aboard a Delta II rocket carrying Canada’s Radarsat-2 mission. However, subsequent delays in the Radarsat-2 program have pushed its launch to the end of 2004 or beyond. Access to space was extremely important to the MOST mission because of the revolutionary science that is being done. Consequently, the Canadian Space Agency contracted with Eurockot to provide launch services using a “Rockot” launch vehicle launching from Plesetsk, Russia. As we prepare for the launch in June 2003, the paper will present a summary of the science goals of the mission, will highlight the progress of the integration team in preparing the satellite for launch, and will reflect on the impact that changing launch vehicles has had on the satellite in our quest for access to space.

The MOST (Microvariability and Oscillations of STars) astronomy mission under the Canadian Space Agency's Small Payloads Program is Canada's first space science microsatellite and is scheduled to launch in June 2003. The MOST science team will use the satellite to conduct long-duration stellar photometry observations in space. The primary science objectives include: measuring light intensity oscillations in solar type stars; determining the age of nearby "metal-poor sub-dwarf" stars, which will in turn allow a lower limit to be set on the age of the Universe; and detecting the first reflected light from orbiting exoplanets and using it to determine the composition of their atmospheres. To make these measurements, MOST incorporates into a microsatellite design a small (15 cm aperture), high-photometric-precision optical telescope and a high performance attitude control system that is revolutionary in its pointing accuracy for a microsatellite. A key hurdle that the MOST mission had to overcome was that of access to space. MOST as initially conceived was designed to launch as a secondary payload aboard a Delta II rocket carrying Canada's Radarsat-2 mission. However, subsequent delays in the Radarsat-2 program have pushed its launch to the end of 2004 or beyond. Access to space was extremely important to the MOST mission because of the revolutionary science that is being done. Consequently, the Canadian Space Agency contracted with Eurockot to provide launch services using a "Rockot" launch vehicle launching from Plesetsk, Russia. As we prepare for the launch in June 2003, the paper will present a summary of the science goals of the mission, will highlight the progress of the integration team in preparing the satellite for launch, and will reflect on the impact that changing launch vehicles has had on the satellite in our quest for access to space.

The Microvariablity and Oscillations of Stars ( MOST) mission is a low-cost microsatellite designed to detect low-degree acoustic oscillations ( periods of minutes) with micromagnitude precision in solar-type stars and metal-poor subdwarfs. There are also plans to detect light reflected from giant, short-period, extrasolar planets and the oscillations of roAp stars and the turbulent variability in the dense winds of Wolf-Rayet stars. This paper describes the experiment and how we met the challenge of ultraprecise photometry despite severe constraints on the mass, volume, and power available for the instrument. A side-viewing, 150 mm aperture Rumak-Maksutov telescope feeds two frame-transfer CCDs, one for tracking and the other for science. There is a single 300 nm wide filter centered at 525 nm. Microlenses project Fabry images of the brighter (V less than or equal to 10) target stars onto the science CCD. Fainter target stars will be focused directly elsewhere on the CCD. MOST was launched on 2003 June 30 into a low-Earth, Sun-synchronous, polar orbit allowing stars between -19degrees and +36degrees declination to be viewed continuously for up to 60 days. Attitude is controlled by reaction wheels and magnetotorquers. A solar safety shutter over the telescope diagonal is the only other moving part. Accumulated photometry will be used to calibrate response across the target field stop, and data will be compressed and downloaded to three dedicated ground stations.

Conclusion This Note proposes a method of path planning for space manipulators that reduces disturbances to the spacecraft attitude. The proposed method uses the EDM for planning the manipulator path in the joint space. The method sequentially determines the direction of small steps of joint movements that compromises the biobjectives of minimizing the disturbance to the spacecraft attitude and realizing the terminal end effector position. Numerical simulations have been made for a space robot with a two-link manipulator. The results of the simulations show the feasibility of the present path planning algorithm.

The middeck active control experiment (MACE) was designed as a Space Shuttle flight experiment to demonstrate high authority active structural control in zero-gravity (0-g) conditions based on analysis, ground testing, and on-orbit control redesign. MACE is a multidisciplinary project that is at the forefront of flexible structural control. MACE was first flown on STS-67 in March 1995, and a summary of the program objectives and mission experimental results is provided.

The Multiple Mirror Telescope (MMT) under development at the University of Arizona takes a new approach in adaptive optics placing a large (0.65 m) force-actuated, thin facesheet deformable mirror at the secondary of an astronomical telescope, thus reducing the effects of emissivity which are important in IR astronomy. However, The large size of the mirror and low stiffness actuators used drive the natural frequencies of the mirror down into the bandwidth of the atmospheric distortion. Conventional adaptive optics takes a quasi-static approach to controlling the, deformable mirror. However, flexibility within the control bandwidth calls for a new approach to adaptive optics. Dynamic influence functions are used to characterize the influence of each actuator on the surface of the deformable mirror. A linearized model of atmospheric distortion is combined with dynamic influence functions to produce a dynamic reconstructor. This dynamic reconstructor is recognized as an optimal control problem. Solving the optimal control problem for a system with hundreds of actuators and sensors is formidable. Exploiting the circularly symmetric geometry of the mirror, and a suitable model of atmospheric distortion, the control problem is divided into a number of smaller decoupled control problems using circulant matrix theory. A hierarchic control scheme which seeks to emulate the quasi-static control approach that is generally used in adaptive optics is compared to the proposed dynamic reconstruction technique. Although dynamic reconstruction requires somewhat more computational power to implement, it achieves better performance with less power usage, and is less sensitive than the hierarchic technique.

The middeck active control experiment (MACE) is a space shuttle flight experiment intended to demonstrate high authority active structural control in zero gravity (0-g) conditions based on analysis and ground testing. Finite element structural models are very important for the MACE program because they can be used to predict the on-orbit dynamics of the test article. However, finite element models tend to be inaccurate, requiring the use of parametric robust control techniques to achieve good performance. Several such control techniques and an overall design methodology are discussed in this paper. Experimental results from several tests are used to illustrate the feasibility of achieving good H/sub 2/ performance on the test article with robust controllers based on the finite element model. This demonstration improves confidence in the eventual on-orbit performance of this experiment and other future spacecraft.

Analysis of a control system design prior to implementation is critical for determining expected stability and performance of the true system. For the Middeck Active Control Experiment (MACE), a Shuttle Middeck experiment which flew on STS-67 in March 1995, two distinct analysis procedures are followed. One utilizes open loop data which is only available during the flight. The other involves development and use of an uncertainty model and a mixed-μ analysis to test for stability over the full range of uncertainty. Using the extensive on-orbit data accumulated during the 14-day Shuttle mission, the effectiveness of both procedures is assessed

This paper presents closed loop results and insight from the on-orbit experiments of the Middeck Active Control Experiment (MACE). MACE was flown in the shuttle middeck on STS-67 in March 1995 to investigate issues associated with a change in operational environment from ground to space based operations of a payload pointing spacecraft that cannot be tested in a realistic ground simulation. These results show that equivalent performance can be obtained using finite element based and measurement based control, the benefits available from testing a structure on the ground, even in a different configuration to that used on-orbit, and the limitations associated with various control topologies. These MACE results provide much insight into how future on-orbit closed loop experiments can be improved.

of this paper is to compare control techprovide robustness for parametric uncertainty in structural systems. Sensitivity Weighted LQG, Maximum Entropy, Multiple Model, 'Hm and psynthesis were selected from amongst the available techniques, and are compared herein. The techniques are evaluated on: 1) computational requirements; 2) the degree to which performance is sacrificed in order to achieve robustness and 3) the maximum performance experimentally achieved on the Middeck Active Control Experiment test article. These criteria determine which techniques are suitable for the design of robust compensators for large order structural systems with parametric

This paper presents a coherent methodology for robust controller synthesis for the Middeck Active Control Experiment (MACE): a Shuttle program scheduled for flight on STS-67 in February 1995. The experiment has been designed to investigate the extent to which the on-orbit behavior of a precision-controlled spacecraft can be predicted and controlled using analysis and ground testing prior to launch. A goal of the flight experiment is to demonstrate good payload pointing performance using active controllers designed based on the predicted structural dynamics. For systems with complicated control topologies and large model uncertainties, this requires a systematic control design methodology. The results from preliminary ground-based control experiments are used in this paper to present such st design technique and to illustrate how it can be applied to future flight experiments. This control design methodology is then used to develop controllers that obtain a 22 dB improvement in the performance metric on the current MACE hardware.