ESTCube-1

ESTCube-1 is the first Estonian satellite and first satellite in the world to attempt to use an electric solar wind sail (E-sail). It was launched on 7 May 2013 aboard Vega VV02 carrier rocket[3][4] and successfully deployed into orbit.[5] The CubeSat standard for nanosatellites was followed during the engineering of ESTCube-1, resulting in a 10x10x11.35 cm cube, with a volume of 1 liter and a mass of 1.048 kg.[6][7]

The mission ended in 17 February 2015 and it was said that during this time it resulted 29 bachelor's and 19 master's dissertations, 5 doctoral theses and 4 start-ups.[8] The deployment of the E-sail was unsuccessful, and no measurements were taken of the E-sail or of the plasma braking deployment system.[9]

ESTCube-1
ESTCube-1 illustration
ESTCube-1 illustration
Mission typeTechnology
OperatorUniversity of Tartu
COSPAR ID2013-021C
SATCAT no.39161
Websitehttp://www.estcube.eu/en/home
Mission duration12 months
Spacecraft properties
Launch mass1.048 kilograms (2.31 lb)
Dry mass1.048 kilograms (2.31 lb)
Power3.6W [1]
Start of mission
Launch date7 May 2013, 02:06:31 UTC
RocketVega flight VV02
Launch siteKourou ELA-1
ContractorESA
End of mission
Deactivated17 Feb 2015, 10:27:00 UTC[2]
Last contact19 May 2015[1]
Decay date2038*estimated
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Perigee665 km
Apogee665 km
Inclination98.129 degrees
Period98.03 minutes
 

Scientific purpose

The first image of the Earth, taken by ESTCube-1 nanosatellite.
The first image of Earth taken by ESTCube-1 on May 15, 2013.[5]
ESTCube-1 E-sail experiment
ESTCube-1 E-sail experiment
The structure of cubesat ESTCube-1 eng
The structure illustration of cubesat ESTCube-1
ESTCube-1 struktuur koos plaatidega
ESTCube-1 structure

Developed as part of the Estonian Student Satellite Program, ESTCube-1 was an educational project in which university and high school students participated.[10][11]

While emphasis was placed on educating students during creation of ESTCube-1, it did have a scientific purpose. The satellite carried an electric solar wind sail (E-sail) which was invented by Finnish scientist Pekka Janhunen. During the ESTCube-1 flight, 10 meters of 20–50 micrometer thick E-sail wire, sometimes referred to as "Heytether," were to be deployed from the satellite. The deployment of the Heytether was to be detected by a decrease of the satellite's rotation speed or an onboard camera.[12]

To control the E-sail element's interaction with both the plasma surrounding the Earth and the effect it had on the spacecraft's spinning speed, two nanotechnology electron emitters/guns were on board. The electron emitters were connected to the E-sail element which was to be charged positively to 500 volts by shooting out electrons. The positive ions in the plasma were intended to push the E-sail element and influence the satellite's rotation speed. The effect of the plasma on the E-sail was to be measured by the change in said rotation speed. The tether had also been intended to de-orbit the satellite by use as a plasma-brake to demonstrate a possibility for returning small satellites from orbit. A color CMOS camera was also on board that was capable of making RAW-format pictures with VGA-resolution. This camera was used to acquire images of Earth and had been intended to monitor deployment of the Heytether.

Orbit

To complete the scientific experiment and communicate with the satellite on several occasions the orbit chosen was a sun–synchronous circular orbit at an altitude of 670 kilometers. ESTCube-1 was launched into orbit by Arianespace, using Vega VV02 rocket which lifted off from ELA-1 at Kourou at 02:06:31 UTC on 7 May 2013. The satellite was placed into orbit and communication successfully established,[13] with the first photo of the Earth taken on May 15 and transmitted to the ground on the amateur radio band.[5]

Lifespan of the satellite

The plan, beginning with the 7 May 2013 launch, included the following steps:

  • Half an hour after the satellite's deployment from the start capsule, the satellite's antennas were deployed and radio transmitter and important subsystems were switched on.
  • During first 48 hours after the deployment, the satellite sent only safe-mode CW beacon signals
  • The first weeks were used to test the satellite and set it to work at full capacity.
  • Orientation of the satellite so the on-board camera was facing Earth to acquire images of Estonia.
  • Rotation of the satellite on its longitudinal axis with a speed of 1 revolution per second.
  • E-Sail element deployment from the satellite by centrifugal force was attempted, however, the deployment failed, possibly due to a stuck reel.[1] No confirmation of the deployment was received via the on-board camera, and further E-sail experiments were not conducted.

End of mission

The mission ended due to degradation of the photovoltaic power system[1] and subsequently the batteries became exhausted. The last morse code transmission was transmitted on 17 February 2015. The plan to test a solar sail the satellite carried failed since the sail cable unwinding mechanics did not survive the rocket takeoff vibration.[9]

Design

Measurements and weight

During the development of the Estonian satellite mission it was decided to make a 1U CubeSat. By standard 1 unit (1U) CubeSat base side length must be 100.0±0.1 millimeters and satellite height must be 113.5±0.1 mm. Mass is also set in CubeSat standard, the highest possible mass for 1U CubeSat is 1300 grams.

Communications

Communication from the satellite is made at two International Amateur Radio Unions registered frequencies

  • 437.250 MHz
  • 437.505 MHz[14]

Periodic but very slow communication was made by using 18 WPM telegraphy signal on a frequency of 437.250 MHz. At that frequency, the most important satellite parameters are returned every 3 to 10 minutes. For fast connections FSK-modulation radio signals on a frequency of 437.505 MHz with a 9600 baud connection speed and AX.25 packet standard is used. The relatively slow connection speeds result from the use of amateur radio frequencies which limits the bandwidth to 25 kilohertz. The fast connection is used only when the satellite has been given a specific order. Both telegraphy and packet telemetry protocols of ESTCube-1 are published on project webpage.[15][16]

Commands sent to the satellite used the 145 MHz (2 meter) amateur band.

Software

ESTCube-1 microcontrollers use the following operating systems:

  • FreeRTOS on the satellite's Command and Data Handling System and camera module.
  • TinyOS on the satellite's communication module. (Typically used with devices running on low power)

Mission Control System is currently being developed by the students of Tartu University under the supervision of the company CGI Group.

Financing and costs

ESTCube-1 esitlus
ESTCube-1 presentation in January 2013.

ESTCube-1 was launched as a secondary payload onboard Vega flight VV02,[4] the least expensive satellite launch offered by the European Space Agency. Because Estonia is an associated member of ESA, most of the launch expenses (about 70,000 euros) were covered by the Estonian member fee for educational expenses. With the launch, total expenses for the project were approximately 100,000 euros.

Results

The satellite successfully demonstrated the operation of the systems in space, with a two-year operational life. The deployment of the E-sail was unsuccessful, and no measurements were taken of the E-sail or of the plasma braking deployment system.[9]

See also

References

  1. ^ a b c d Vladislav-Veniamin Pustõnski, ESTCube-1 ceased working after 2 years in orbit, Estonian Space Office (accessed 8 June 2016)
  2. ^ "ESTCube-1's 651-day career: 53 dissertations and a marriage proposal". 17 Feb 2015.
  3. ^ esa. "Launch schedule".
  4. ^ a b Amsat-UK, ESTCube-1. Retrieved 13 April 2017.
  5. ^ a b c Southgate Radio Amateur News, First picture from ESTCube-1 ham radio CubeSat, May 22, 2013 (accessed Aug. 16 2013)
  6. ^ "Estonia's student cubesat satellite is ready for the next Vega launch". Arianespace. Archived from the original on March 28, 2013. Retrieved March 25, 2013.
  7. ^ "ESTCube-1 mentioned in Nature's regional report". 17 Nov 2010.
  8. ^ "ESTCube-1's 651-day career: 53 dissertations and a marriage proposal" ERR, 17 February 2015
  9. ^ a b c "ESTCube-1 sends its last words: "Long live Estonia!"". 17 Feb 2015.
  10. ^ "The two primary payloads for Vega's second launch are readied at the Spaceport". Arianespace. March 14, 2013. Archived from the original on March 19, 2013. Retrieved March 25, 2013.
  11. ^ "Arianespace Awaits... Vega Tops Off While Sats Prep For Vegies (Launch)". satnews. March 14, 2013. Retrieved March 25, 2013.
  12. ^ "Proba-V's fellow passenger" (PDF). European Space Agency. February 2013. p. 17. Retrieved March 25, 2013.
  13. ^ Matteo Emanuelli, Estonian Cubesat on a Collision Course with Iridium-Cosmos Debris, August 1, 2013, Space Safety News (accessed Aug. 16 2013)
  14. ^ "ESTCube-1". International Amateur Radio Union. 15 Mar 2013. Retrieved March 25, 2013.
  15. ^ "Telemetry packet description". Retrieved August 5, 2014.
  16. ^ "Beacon decoding". Retrieved August 5, 2014.

External links

Videos
2013 in spaceflight

In 2013, the maiden spaceflight of the Orbital Sciences' Antares launch vehicle, designated A-ONE, took place on 13 April. Orbital Science also launched its first spacecraft, Cygnus, that docked with the International Space Station in late September 2013.

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Amateur radio satellite

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Many amateur-satellites receive an OSCAR designation, which is an acronym for Orbiting Satellite Carrying Amateur Radio. The designation is assigned by AMSAT, an organization which promotes the development and launch of amateur radio satellites. Because of the prevalence of this designation, amateur radio satellites are often referred to as OSCARs.

These satellites can be used for free by licensed amateur radio operators for voice (FM, SSB) and data communications (AX.25, packet radio, APRS). Currently, over 18 fully operational amateur-satellites in orbit act as repeaters, linear transponders or store and forward digital relays.

Throughout the years, amateur-satellites have helped make breakthroughs in the science of satellite communications. A few advancements include the launch of the first satellite voice transponder (OSCAR 3) and the development of highly advanced digital "store-and-forward" messaging transponder techniques.

The information presented regarding functional satellites is outdated quickly as the Amateur Radio Satellite community has become very active in building and being provided educational secondary cargo launch opportunities. For current information please visit AMSAT for North America https://www.amsat.org/ and AMSAT-UK for Europe https://amsat-uk.org/

ELA-1

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ESTCube-2 is an Estonian satellite slated for launch in 2019. It is a prototype for ESTCube-3, an Estonian moon orbiting mission planned for the early 2020s. ESTCube-2's primary objectives are to test a "plasma brake" for deorbiting satellites and to test electric sail propulsion technology. It will reduce its orbit using a 300m tether which interacts with the ionospheric plasma. The orbit will go from a 700 km altitude orbit to a 500 km altitude one in a half year.

Electric sail

An electric sail (also known as an electric solar wind sail or an E-sail) is a proposed form of spacecraft propulsion using the dynamic pressure of the solar wind as a source of thrust. It creates a "virtual" sail by using small wires to form an electric field that deflects solar wind protons and extracts their momentum. The idea was first conceptualised by Pekka Janhunen in 2006 at the Finnish Meteorological Institute.

Estonian Space Office

The Estonian Space Office (ESO; Estonian: Eesti Kosmosebüroo) is the unit established within Enterprise Estonia by the Government of Estonia to facilitate membership in the European Space Agency and related commercial and research ties. In addition ESO serves as a contact point with the IAF, EURISY and EUMETSAT in procurement-related matters.ESO is not a space agency. State space policy as it exists is managed through the Space Affairs Council at the Ministry of Economic Affairs and Communications. ESO functions as a centre for technology and business competence alongside Tartu Observatory which has responsibility for space science, space exploration and remote sensing. Various activities within the Framework Programmes for Research and Technological Development of the European Union for education, science and innovation, including funding for space programs, are coordinated by the Archimedes Foundation.Since 2010, the Riigikogu has had a 'Space Studies Support Group' (Kosmose valdkonna toetusrühm) currently chaired by Anne Sulling.

Finnish Meteorological Institute

The Finnish Meteorological Institute (Finnish: Ilmatieteen laitos, Swedish: Meteorologiska institutet, or simply FMI) is the government agency responsible for gathering and reporting weather data and forecasts in Finland. It is a part of the Ministry of Transport and Communications but it operates semi-autonomously.

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Pekka Janhunen

Pekka Janhunen, Ph.D., is a researcher in Finnish Meteorological Institute. He is best known for his Electric Solar Wind Sail invention.

Rendering (computer graphics)

Rendering or image synthesis is the automatic process of generating a photorealistic or non-photorealistic image from a 2D or 3D model (or models in what collectively could be called a scene file) by means of computer programs. Also, the results of displaying such a model can be called a render. A scene file contains objects in a strictly defined language or data structure; it would contain geometry, viewpoint, texture, lighting, and shading information as a description of the virtual scene. The data contained in the scene file is then passed to a rendering program to be processed and output to a digital image or raster graphics image file. The term "rendering" may be by analogy with an "artist's rendering" of a scene.

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Rendering is one of the major sub-topics of 3D computer graphics, and in practice is always connected to the others. In the graphics pipeline, it is the last major step, giving the final appearance to the models and animation. With the increasing sophistication of computer graphics since the 1970s, it has become a more distinct subject.

Rendering has uses in architecture, video games, simulators, movie or TV visual effects, and design visualization, each employing a different balance of features and techniques. As a product, a wide variety of renderers are available. Some are integrated into larger modeling and animation packages, some are stand-alone, some are free open-source projects. On the inside, a renderer is a carefully engineered program, based on a selective mixture of disciplines related to: light physics, visual perception, mathematics, and software development.

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Satellite

In the context of spaceflight, a satellite is an artificial object which has been intentionally placed into orbit. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as Earth's Moon.

On 4 October 1957 the Soviet Union launched the world's first artificial satellite, Sputnik 1. Since then, about 8,100 satellites from more than 40 countries have been launched. According to a 2018 estimate, some 4,900 remain in orbit, of those about 1,900 were operational; while the rest have lived out their useful lives and become space debris. Approximately 500 operational satellites are in low-Earth orbit, 50 are in medium-Earth orbit (at 20,000 km), and the rest are in geostationary orbit (at 36,000 km). A few large satellites have been launched in parts and assembled in orbit. Over a dozen space probes have been placed into orbit around other bodies and become artificial satellites to the Moon, Mercury, Venus, Mars, Jupiter, Saturn, a few asteroids, a comet and the Sun.

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A launch vehicle is a rocket that places a satellite into orbit. Usually, it lifts off from a launch pad on land. Some are launched at sea from a submarine or a mobile maritime platform, or aboard a plane (see air launch to orbit).

Satellites are usually semi-independent computer-controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control and orbit control.

Small satellite

Small satellites, miniaturized satellites, or smallsats, are satellites of low mass and size, usually under 500 kg (1,100 lb). While all such satellites can be referred to as "small", different classifications are used to categorize them based on mass. Satellites can be built small to reduce the large economic cost of launch vehicles and the costs associated with construction. Miniature satellites, especially in large numbers, may be more useful than fewer, larger ones for some purposes – for example, gathering of scientific data and radio relay. Technical challenges in the construction of small satellites may include the lack of sufficient power storage or of room for a propulsion system.

Space science in Estonia

The cornerstone of the Estonian cosmological research is the Tartu Observatory which was founded in 1812. The observatory itself has a long tradition of studying galaxies and theoretically modeling the structure of the universe and its formation. Till today this facility is Estonia’s main research centre for astronomy and atmospheric physics, with fundamental research focusing on physics of galaxies, stellar physics and remote sensing of the Earth’s atmosphere and ground surface. The observatory has also played a vital role in catapulting the career of Jaan Einasto, one of the most famous and eminent Estonian astrophysicists and one of the discoverers of "Dark Matter" and of the cellular structure of the Universe.

Space tether missions

A number of space tethers have been deployed in space missions. Tether satellites can be used for various purposes including research into tether propulsion, tidal stabilisation and orbital plasma dynamics.

The missions have met with varying degrees of success; a few have been highly successful.

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TinyOS

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TinyOS has been used in space, being implemented in ESTCube-1.

University of Tartu

The University of Tartu (UT; Estonian: Tartu Ülikool, Latin: Universitas Tartuensis) is a classical university in the city of Tartu, Estonia. It is the national university of Estonia. The University of Tartu is the only classical university in the country and also the biggest and most prestigious university in Estonia. It was established by King Gustavus Adolphus of Sweden in 1632.

There are nearly 14,000 students at the university, of which over 1,300 are foreign students. The language of instruction in most curricula is Estonian, but there are some more notable exceptions that are taught in English, such as Semiotics, Applied Measurement Science, Computer Science, Information Technology Law and European Union – Russia Studies.The historical buildings of the university are included in the European Heritage Label list as "embodiment of the ideas of a university in the Age of Enlightenment".The University of Tartu is a member of the Coimbra Group and the Utrecht Network.

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Vega flight VV02

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