On scientific-educational
program of university
pico-satellites development V.M.Matrosov,
V.G.Veretennikov Scientific-educational
Center of MAI and Institutes of RAS Volokolamskoe shosse, 4, Moscow,
A-80, GSP-3, 125993, Russia In this paper we review the development of small Earth
satellites of various purposes and missions in universities of Russia, Japan,
USA, Norway, especiallyš the satellites
with mass of 1 kg and volume of 1 dm3 which are called
"pico-satellites". Using two or more Lyapunov functions, we can study the
problems of asymptotical stability on a whole and stabilization of such small
Earth satellites. Considering gravitational, aerodynamic and other disturbances
in geomagnetic field, we can get quantitative estimation of deviation and prove
the stability at constant disturbances of the chosen class. We set a task to
form the educational and scientific program to develop pico-satellites of the
second generation. This development is to be done by students and postgraduates
of Russian universities (Mozhaisky Moscow Aviation Institute, Kazan State
Technical University, St.-Petersburg State Aviation University) in partnership
with foreign technical universities and in future (phase of pico-satellites
design and launch) in partnership with scientific research institutes and
design bureaus of Russian Space Agency. Concept of CubeSat and
its significance "CubeSat" was proposed by Professor R. Twiggs
at University Space Systems Symposium 1999. It is 10cm cubic nano-satellite
with 1 kg weight. The standard size facilitates the technology exchanges as
well as co-launch of multi-satellite with same separation systems. It is
emphasized that it is very important for students to experience the whole cycle
of space project, including mission conceptualization, satellite design,
fabrication, ground test and feedbacks of the results, launch and operation.
The most important thing is that the space engineering education should include
the phase of experiments in the real environment, because the feedbacks from
the real world teach students what is important and what is not. Besides, the
hands-on-training provides students with a good opportunity for training
project management and team working. Students can learn how to manage the time,
cost, human resource and risk, how to organize meetings and how to write and
use documents. Development of nano-scale satellite has another
important effect. Nano-satellites which can be developed within 1 to 1,5 year
with extremely low cost have a possibility of opening new space missions and
business, enabling quick and low-cost demonstration of novel space
technologies. Considering these effects, more than 30 universities and research
institutes as well as venture business are currently pursuing their own CubeSat
projects. Some projects of CubeSat
realization in different countries
USA Program KUTESat Kansas
Universities technology evaluation satellite Program. The KUTESat Program tests miniature
technologies using pico-class (1 kg) satellites. The program consists of three
phases involving two satellite missions in low Earth orbit and an engineering
prototype using an aircraft. The first phase's objective is to develop and
operate a simple pico-satellite, with launch on a Dnepr rocket. The final phase
has three autonomous satellites fly simultaneously. One is an inspector,
another senses space environment, and the third is a target and relay
satellite. The CubeSat standard was set by Stanford
University so that the satellites will be similar enough that information and
solutions can be easily shared. The result has been a free flow of information
between the various CubeSat teams, thus providing many solutions that can be
studied to solve various problems of satellite building and operation. These
satellites use mostly off-the-shelf parts that are inexpensive and easily
obtainable. More than 30 universities around the world have started the design
of a CubeSat. The first launch of 6 CubeSats was in June, 2003. Even though a
couple experienced problems, they successfully proved the concept. In the past three years, many papers about this
system have been presented in the most prestigious conferences, demonstrating
that students are learning and contributing to research. The majority of
universities that have started a CubeSat program consider it primarily as a
means to instruct students about spacecraft and space science. As a
consequence, they start and develop projects that are very interesting from a
scientific point of view, but are not part of a global plan. The University of Kansas team has recognized
the potential of this class of satellites to become a primary answer to many of
the challenges that the space business is facing. The Kansas Universities'
Technology Evaluation Satellite (KUTESat) program goal is to develop the
capabilities to design, build and test satellites that will meet those
challenges, and only a systematic development of the program and of the
facilities available will allow success. The technical objective of the KUTESat program
is the development and operation of small pico-satellites that can demonstrate
and test technologies and techniques necessary to accomplish various commercial
and NASA missions. The core KUTESat program consists of 2 basic
tracks, starting with a Balloonsat precursor and the first satellite,
KUTESat-1, called Pathfinder. Inspection Sensor Satellite (ISS). This KUTESat will be the prototype
pf pico-probes that will do imaging inspection of space vehicles (e.g.,
inspecting satellites in orbit or even for inspecting the International Space
Station for NASA). Some possible missions for such an inspection probe include: -
Investigation
of anomalies -
Monitor
performance of mother ship systems -
Inspect
foreign objects -
Verify
safety -
Aid
deployment and calibration Technical Solutions This satellite will have full translation and
rotational maneuvering capability, provided by the miniature maneuvering
control system (MMCS), to enable it to autonomously fly around the target
satellite and point the imaging camera based on uploaded commands. It will be
basically autonomous with guidance capability in the vicinity of the target.
This will be provided by a radio or similar beacon on the target to provide
direction to the target, or by autonomous image analysis (e.g., using colors or
shapes). Space Environment Satellite (SES). The second autonomous satellite will
be similar to the ISS except that instead of an imager, it will contain space
environment sensors, such as dosimeters and micrometeoroid detectors. It will be required to have translation
maneuvering capability and the ability to hold attitude for the translation
maneuvers. Target & Relay Satellite (TRS). This satellite
provides 2 purposes - as a target for ISS, and as a relay satellite for both
the ISS and the SES to communicate with the ground. Germany UWE-1
(University Würzburg's Experimental). The primary research task
of the Würzburg CubeSat is to provide a space-based platform to
investigate using internet-based node methodology to provide communications
with small research spacecraft. A complementary objective is to provide an
educational learning experience for students in the design, fabrication,
testing and operations of small satellite systems. The Würzburg spacecraft is designed
primarily as a spacecraft for communication purposes. Its antenna pattern has
been nominally designed as omni-directional, so that the spacecraft need not be
pointed in any specific direction for proper operation. The first attitude
control requirement is that the spacecraft have a small rotational rate. The
spacecraft should not rotate outside of its hemisphere within the time of one
ground contact. To accomplish that, rates with respect to the orbital
coordinates must be kept under 0.01 rad/sec. Technical
Properties. The implementation of a fully magnetic attitude determination system is
unique and can be considered as an experiment. Therefore attitude determination
and control accuracy values are assumed to be goals, rather than requirements.
These goals include an attitude determination uncertainty of less than 3œ and a control accuracy of 7,5œ. Technical
Solutions. A goal of this
project was to develop a simple attitude determination and control system which
can operate under the constraints of the CubeSat program. Based on size, power,
and cost constraints, the only feasible option was to use a completely magnetic
attitude determination and control system. This approach has several well known
difficulties. A single magnetic fields measurement does not provide sufficient
information for attitude determination, making the system unobservable. Also a
magnetic torque cannot be applied in the direction of the magnetic field,
making the system uncontrollable. Simulation results indicate that the
Würzburg CubeSat can be stabilized using a simple PD control algorithm
coupled with projecting the resulting torque command onto a plane perpendicular
to the magnetic field vector. The controller provides a nadir pointing accuracy
of approximately 4œ. Japan Nano-satellite
The missions of University of Tokyo's
CubeSat-XI are as follows: -
Space
engineering education -
On-orbit
demonstration of nano-scaled satellite bus technologies -
RF
communication experiment using amateur frequency -
Attitude
estimation using solar cell output information on six surfaces -
Earth
image capture and downlink Technical Solutions. CubeSat-XI uses amateur radio
frequency and so has to apply to AMSAT for frequency coordination and apply to
Japanese government for license for space and ground RF stations. The data
format has been made open to the public so that any radio amateurs can access
the down linked RF signal, as dictated in AMSAT regulations. Usage of COTS
parts is the important part of the project, because by so doing, the satellite
development can be made very low cost and not time consuming because the lead
time before obtaining parts can be drastically reduced. In order to verify the
performance of the COTS based subsystems, space environment tests have been performed
including vibration tests, radiation tests, thermal tests, vacuum tests, and
thermal vacuum tests. Tokyo tech
pico-satellite "CUTE-1" (Cubical Tokyo Tech Engineering Satellite-1). Tokyo Institute of Technology,
Laboratory for Space Systems had developed a 1 kg pico-satellite CubeSat,
CUTE-I, and it was successfully launched on June 30, 2003 by a Eurockot rocket.
CUTE-I is one of the first launched CubeSats and also the smallest civilian
satellites in the world. CUTE-I has communication, sensing, and deployment
missions. CUTE-I has 4 small piezoelectric vibrating gyroscopes, 4 small
accelerometers, thermistors and a CMOS sun sensors. After CUTE-I is separated
from the launcher, a power switch of CUTE-I is turned on. Then CUTE-I stores
sensor data in its on-board memory. The initial data will be very useful to
analyze CUTE-I state at separation. After a few minutes from separation, CUTE-I
starts deploying three monopole antennas and the solar paddle. Then CUTE-I
starts transmitting CW telemetry. Norway nCube Satellite. The satellite, named nCube, is based
on the CubeSat concept. This means that its size is restricted to a cube
measuring 10 cm on all sides and that its total mass is restricted to 1 kg.
Meeting these restrictions represents the main technical challenge of the work.
The complete cube includes the payload, ADCS with actuators and sensors,
deployable antennas, commu-nication systems, on board data handling (OBDH) and
power system. Miniaturization is a key approach in order to meet the tight mass
budget. The Determination part of the ADCS is solved by integrating
measurements from a three-axis magnetometer with current measurements from the
solar panels in a Kalman filter. The solar panes are used as crude sun sensors.
The Control part is solved by using a combination of magnetic coils and gravity
boom. The control system operates in one of two modes: 1) Detumbling and 2)
Stabilization. The control laws are derived using Lyapunov theory, and
stringent stability proofs are given. On mission from The Norwegian Space
Center and Andeya Rocket Range, four Norwegian universities and educational
institutes have since 2001 participated in a program to develop a
pico-satellite known as nCube. The project was split into the subtasks:
Mechanical Struc-ture, Power System, Altitude Determination and Control System
(ADCS), Payload, Space Communication System (COM), and Ground Segment (GSEG).
The ADCS was developed by the Department of Engineering Cyber-netics at NTNU.
The main mission of the satellite is to demonstrate ship traffic surveillance
from a LEO satellite using the maritime Automatic Identification System (AIS)
recently introduced by the International Maritime Organization (IMO). The AIS
system is based on VHP transponders located on board ships. These transponders
broadcast the position, speed, heading and other relevant information from the
ships at regular time intervals. The main objec-tive of the satellite is to
receive, store and retransmit at least one AlS-message from a ship. In ad-dition,
the satellite should maintain communications and digipeater operations using
amateur frequencies. As the system architecture must allow the partners in the
project to design and test their systems independently, the basic system
architecture does not contain a centralized CPU. Instead, we use a pipelined
structure where each subsystem contains their own on board data handlers
(OBDH). By using this architecture, it is possible to test and verify each
subsystem independently during the implementation phase. The satellite will be
placed in a low earth sun synchro-nous orbit with a perigee of approximately
700 km, and as circular as possible. The inclination will be close to 98œ. The
launch is scheduled to the second half of 2004 from Dnepr, Ukraine. Sweden-Russia Several years ago it was decided to start the
development of nano-satellite, named "Munin". "Munin" mission is
to collect data about the effects in lower layers of Earth atmosphere and
ionosphere and to transmit the data about magnetosphere state via Internet
online. The satellite is a cube of 21cm side and of 6
kg mass. It has a passive magnetic attitude determination system developed by
Russian scientists M. Yu. Ovchinnikov and V. I. Penkov (M. V. Keldysh Institute
of Applied Mathematics). According to present classification, it's a satellite
of nano class. "Munin" was launched successfully on November 21, 2000. Russia Russian
multi-functional education-research student's satellite "Mozhaetz". In 2000 A.F.Mozhaisky Military Space
Academy launched micro-satellite "Mozhaetz" and successfully carried out
experiments with the use of it in the frameworks of the "Program of new
technologies development using properties and possibilities of
micro-satellites." Experiments aimed to study the effects of space environment
on the on-board electronics and to study the possibilities of orbit parameters
determination using radio navigation system of the satellite. The goal of the
experiments was also to develop modern advanced methodology of spacecraft
control technology in the Academy. "Mozhaetz" was made on the base of
conversion vehicles by "Prikladnaya Mechanika", M. F. Reshetnev Scientific
Industrial Union (Krasnoyarsk) that carried out the technical task of the
Academy. "Mozhaetz" was launched on November 28, 2002 from Plesetsk spaceport.
During "Mozhaetz" flight, students processed the information received in more
than 300 connection sessions with the satellite. They obtained a lot of
important information to analyze the current condition of on-board systems and
flight conditions in the short- and long-range time intervals. Important Missions -
Development
of educational methodology using modern and advanced technologies of spacecraft
control. -
Studies
of space environment effect on the on-board electronics. -
Estimation
of possibilities and accuracy properties of orbit parameters determination
using satellite radio navigation systems GLONASS and GPS. -
Students
hands-on studying of spacecraft motion laws based on the methods of control
theory, telemetry and trajectory data analysis. -
Estimation
of trajectory accuracy properties. The satellite is equipped with: -
GLONASS-GPS
navigation system. -
"Prisma"
dosimeter developed by St.-Petersburg works "Electrostandart" and A.F.Mozhaisky
Military Space Academy engineers. -
Electric
field sensor DEP-AD developed by Novosibirsk State University -
System
of gravity attitude determination, including rod, magnetic accelerator and
electromagnetic device. The satellite weight is 67 kg. It
has a spherical shape with the diameter of approximately 800mm. The main
on-board equipment is located in the pressure container. In 1996 the Academy
opened the Educational Ground Control Complex for research work with "Mozhaetz"
spacecraft. The educational ground station solves the
following tasks: -
Interaction
with the "Mozhaetz" General Flight Control Center in Krasnoznamensk. -
Development
of programs for the spacecraft on-board control. -
Scheduling
the use of Educational Ground Control Complex communication facilities and
operation-technological control of subsystems during control sessions. -
Analysis
of on-board systems working conditions and recommendations on flight program
realization. The Academy Educational Telemetry
Center processes the telemetry data. Students solve the following tasks: -
Receiving
the telemetry data and converting it into the format acceptable for experts in
spacecraft control and analysis and for professional and scientific
publication. -
Development
of recommendations on the further use of the satellite at normal and extreme
flight conditions and transmitting these recommendations to the experts in the
Flight Control Center. Development and further
outlooks of Universities Pico-satellites in Russia It's feasible to start and to extend a
scientific-educational program of Russian aerospace universities initiated by
Moscow Aviation Institute and to continue the pre-discovery at its Applied
Mathematics Faculty. Then it would be efficient to set collaboration with
aerospace and other faculties of the scientific research institute under MAI
and with other Russian aerospace universities which would like to joint the
program and with devoting of this small satellites launches to the important
data: as example, - to the 175th Anniversary of N. E. Baumann Moscow
State Technical University; - to the 250th Anniversary of M. V.
Lomonosov Moscow State University: For 2007 (the 50th date of the first
satellite launch) the European Student Community under European Space Agency is
planning to launch 50 pico-satellites developed in different countries
(including Russia) during the regular Congress of IAF (International
Astronautic Federation) in India References
Vladimir Mefodjevich Matrosov, Academician of RAS, Head of Research
Center of stability and nonlinear dynamics (IMASH RAS), specialist in area of
stability theory and control. Domain of scientific interests: problems of
complex systems analysis and aerospace systems. Victor Grigorievich Veretennikov, Corresponding Member of RAS,
Vice-President of MAI (STU); specialist in area of theoretical mechanics and
nonlinear oscillations. Domain of scientific interests: stability theory of
motion, the theory of oscillations, analytic mechanics. |
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