ISSN 0010-9525, Cosmic Research, 2010, Vol. 48, No. 5 pp. 443–450. © Pleiades Publishing, Ltd., 2010. Original Russian Text © A.A. Sukhanov, H.F. de C. Velho, E.E. Macau, O.C. Winter, 2010, published in Kosmicheskie Issledovaniya, 2010, Vol.48, No. 5, pp. 455–462. 443 1. PROJECT DESCRIPTION Recently, natural satellites were discovered for many asteroids. There are such asteroids with one or two satellites also among the near-Earth asteroids, i.e., asteroids, whose orbits are close to the Earth’s orbit. The investigation of binary or triple asteroid from close distance with the help of a spacecraft can be of considerable scientific interest. At present in Brazil, the development of the project for a flight to binary or triple near-Earth asteroid is started to perform investi- gations from an orbit around the asteroid. The project focuses on low-cost realization with the final space- craft mass near the asteroid not exceeding 100 kg; search for the object among near-Earth asteroids is also dictated by the need to reduce the costs of the project. This paper is devoted to the analysis of trajectories of flight to near-Earth asteroids within the framework of the Aster project. This project is at the very early stage of development, therefore, different (though not all) possible variants for its realization were consid- ered. An analysis of flights to the triple asteroid of the Main Belt (45) Eugenia has been made. This large asteroid is of greater scientific interest than small near- Earth asteroids. However, of course, the flight to the Main Belt asteroid would have required larger expen- diture of both fuel (propellant), and flight time. Larger distance of the Eugenia asteroid from the Sun and the Earth than in the case of near-Earth asteroid would require more powerful power supply and telecommu- nication that would also increase the costs of the project. 2. CANDIDATES AMONG ASTEROIDS Primarily, several binary and triple near-Earth asteroids were selected for the preliminary analysis of transfer trajectories. The characteristics of these aster- oids (candidates) are presented in Table 1, where the following designations are used: P is the orbital period, q, Q are the distances at perihelion and aphelion, respectively, i is the orbit inclination to the ecliptic, and D is diameter. The characteristics of the 45 Euge- nia asteroid are also shown. Note that the diameters of most near-Earth asteroids are determined very approximately. As seen from Table 1, large eccentricity and high inclination of the orbit of the (66391) 1999 KW4 aster- oid would inevitably lead to unacceptably large value of the characteristic velocity required for the flight to the asteroid. Therefore, the 1999 KW4 asteroid was excluded from further analysis. 3. FLIGHTS WITH IMPULSIVE THRUST As a parameter characterizing the admissibility of an asteroid from the point of view of the cost of the characteristic velocity for the flight to it, the sum of ΔV impulses of the launch from the low circular Earth’s orbit and braking near the asteroid was accepted. 1 Val- 1 Generally speaking, this formal summation is not quite correct, since the launch and braking are produced by different engines with different characteristics. However, if the additional acceler- ation with the help of the spacecraft engine is used near the Earth, this summation is possible; if the additional acceleration is not realized, this parameter can be considered as an approxi- mate characteristic of flights. The Aster Project: Flight to a Near-Earth Asteroid A. A. Sukhanov 1 , H. F. de C. Velho 2 , E. E. Macau 2 , and O. C. Winter 3 1 Space Research Institute, Russian Academy of Sciences, Profsoyuznaya ul. 84/32, Moscow, 117997 Russia 2 National Institute for Space Research, Av. dos Astronautas, 1.758 Jd. Granja - CEP: 12227-010 Sao Jose dos Campos, SP Brasil 3 Sao Paulo State University, Av. Dr. Ariberto Pereira da Cunha, 333, 12.516-410 – Guaratingueta, SP Brasil Received March 4, 2010 Abstract—The information on the project being developed in Brazil for a flight to binary or triple near-Earth asteroid is presented. The project plans to launch a spacecraft into an orbit around the asteroid and to study the asteroid and its satellite within six months. Main attention is concentrated on the analysis of trajectories of flight to asteroids with both impulsive and low thrust in the period 2013–2020. For comparison, the char- acteristics of flights to the (45) Eugenia triple asteroid of the Main Belt are also given. DOI: 10.1134/S0010952510050114