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National Space Agency of Ukraine (NSAU)
 

Space is open to exploration by the whole of mankind and thus all space players have a duty to protect the space environment. As a result of rapid space technology development and activities of leading space countries, the amount of space debris is continuously growing which poses a potential threat to the space environment and human activities in space.

Prevention of space debris formation and its reduction when launching vehicles.

The National Space Agency of Ukraine pays special attention to minimization of the space contamination. Following this concept, Ukraine operates, upgrades and develops launch vehicles and spacecraft according to IADC Space Debris Mitigation Guidelines. Improvement of the launch vehicle design in order to prevent the man-caused space contamination is one of the priorities of the National Space Program of Ukraine.

After the 22nd IADC session, Ukraine has conducted a series of research aimed at reduction of the man-caused near-Earth space contamination. A cycle of three consequential launches of Italian spacecraft UniSat-1 (26/09/2000), UniSat-2 (20/12/2002) and Unisat-3 (29/06/2004) were launched into orbit by the Dnepr launch vehicle. These spacecraft operate the equipment capable of registering collisions with nano-particles with the diameter of close to 1 nanometer. Processing of the obtained data by Professor Grazianis team (University of Rome) will help supplement information on the insufficiently explored fine-dyspersated space debris component.

Prediscovery of the concept of using electromagnetic forces for unwanted spacecraft drag in the terrestrial magnetic field was performed. This concept employs the electromagnetic drag effect identical to the effect found in the works of U.S. scientists Robert Hoyt and Robert Forward developing the Terminator Tether electromagnetic drag unit. The suggested drag device version is supposed to be used for spacecraft of a size smaller than those that might be fitted with Terminator Tether. Research in this area envisages a possibility to combine functions of the devices of separation of small spacecraft from the orbital platform with the terrestrial electromagnetic field drag function. Ground tests of the electromagnetic drag devices are planned for 2006. The obtained research results will be detailed in a report at IADC WG 4.

Ground experiments on impacts of high-speed fine particles at the targets manufactured of materials used in spacecraft electronic equipment were conducted. The obtained results demonstrated abnormal ultra-deep penetration of fine particles into the obstacle. At the same time, movement of these particles is accompanied by impulse electromagnetic effects capable of distorting the internal structure of electronic onboard equipment materials with no visible mechanical damage.

Space debris research with Ukrainian radio aids

Ukraine possesses a series of highly effective radioastronomic antenna systems. Lately, these systems are actively used for radar research of natural and man-made objects in the near-Earth space, including monitoring and research of space debris characteristics. This research area is one of the priorities of the National Space Program of Ukraine.

The RT-70 antenna located in Yevpatoria is one of the biggest antenna systems in the world and the only receiving antenna in Europe equipped with a powerful transmitter (up to 200 kW) operating at the 6 cm wavelength. This offers a unique opportunity to radar space objects at the geostationary and high elliptic orbits. Besides, the narrow-band signal reflected from large orbital objects is much more suitable for elaborating the ULB (ultra long base) radio-interferometry location method. This is why trial experiments on satellites and space debris objects were started recently. In 2004, reflected signals from 50 object sized 50 cm to 10 m at GEO, GTO and high elliptic orbits were recorded onto Mk-2 and NRTV terminals. This gave an opportunity to thoroughly elaborate all correlation processing types and obtain interesting results that will be reported at WG 1.

As you know, optical and radar observations and outer space experiments proved the existence of hundreds of thousands of small fragments at all orbit types which pose a major threat for manned spaceships and spacecraft since collisions with small particles happen most frequently. These fragments cannot be tracked from the Earth and their collisions with spacecraft cannot be predicted. The main source of statistic data about tiny space debris fractions are the so-called beam-park experiments when both transmitting and receiving antennas are focused on a certain area for a long period of time. All space debris particles exceeding a certain size defined by the receiving antenna sensitivity and caught in the target area are recorded. Since results of the first experiments were negative, the approach to small fragments observation at GEO was revised. A new beam-track method was used, when directional diagrams of transmitting and receiving antennas are synchronously tracked along the researched orbit and all objects caught in the area are investigated. The beam-track trial experiments were organized in 2004 and 3-hour sessions were held in June, July and September. Bear Lakes (Medvezhyi Ozera) and Noto antennas were used for reception.

In 2004, a series of experiments on space debris radar were conducted. The idea was to emit a continuous signal of approx. 100 kW at the frequency of approx. 5 GHz directed at catalogued spacecraft debris with effective dispersion diameter of approx. 1 m preferably at geostationary orbits. Reference satellites at high elliptic orbits (apogee up to 19,000 km) were also used for testing. Reception was performed by antennas in Russia (Svetloye, Kaliazin, Medvezhyi Ozera), United Kingdom (MERLIN), Italy (Mediccina), Poland (Torun) and China (Shanghai). Reflected signals were received from 19 objects (15 at GEO and 4 at high elliptic orbits). During the session intervals, the above-mentioned antennas also received radio-wave radiation from quasars with coordinates close to space debris objects. This enabled controlling the antenna pointing precision and efficiency of the receiving equipment, and also implementing a new ULB radio-interferometry location method for substantial improvement of position determination by method of differential radioastronomy. Practically all reflected signals from all researched objects were confidently received on all antennas. These investigations will be reported in more detail at WG 1.

In the near space, along with small man-made objects (space debris) one can also observe natural objects such as meteors and meteoric substances. Till 70s of the XX century, the latter type significantly prevailed. Distribution analysis for objects of both types is necessary for research of both current and prospective space contaminations. Ukraine has collected a big amount of radar research data in metric waves of meteor trails in the upper atmosphere. There are telling reasons to believe that many meteor trails are actually space debris products.

An issue of the day is the radar research of star shower basic bodies in the centimetric band. Further development of the ULB radio-interferometry location method is also prospective since it provides high precision in determination of positions of space bodies and consequently their trajectories. Combination of radar and optical methods, ULB technology application, frequency extension towards shorter waves, investigation of natural space objects these are the main areas of further research to be done in Ukraine under the National Space Program.

Restriction of man-caused near-Earth space contamination during space equipment operation.

The National Space Agency of Ukraine continues development of the branch standard - a normative document posing general requirements to space equipment for prevention of space debris formation. The document guidelines are: on-orbit demolition prevention, evacuation of unwanted spacecraft and orbital stages from the densely populated valuable orbital slots and debris release restriction during normal operations. The document is being developed taking into account the current national and international space debris mitigation standards, as well as IADC Space Debris Mitigation Guidelines. The standard will be binding for all space equipment developers and manufacturers in Ukraine. At present, the draft has been sent for evaluation to the national space companies. Upon receipt of comments and amendments, the final edition will be released. The standard is to enter into force by the end of 2006.