SMART-1
SMART -1 (Small Missions for Advanced Research in Technology, English for Small Missions for Advanced Technology Studies ) was the first spacecraft of ESA, which has explored the Earth's moon.
- 3.1 Structure
- 3.2 drive
- 3.3 navigation
- 3.4 Communication
- 3.5 experiments
- 3.6 Development
Mission Objectives
A main objective of the mission was to test a novel solar -powered electric ion propulsion and new navigation and communication techniques. SMART -1 was the third probe used this drive (the first was the American probe Deep Space 1, the second which was launched in May 2003 Japanese Hayabusa ).
After she swung into orbit around the moon, examined SMART -1 from mid-November 2004, the chemical composition of the lunar surface, looking for water in the form of ice. In addition, scientists hope to gain insights of clarifying the origin of the moon approximately 4.5 billion years ago.
History of the flight
Start
SMART -1 was launched on 28 September 2003 at 01:14 CEST clock from the Kourou spaceport in South America French Guiana on board an Ariane 5 rocket from the type first. Into orbit at about 4800 km altitude This lasted about 42 minutes. In addition to SMART -1 were also two communications satellites, the Indian INSAT -3E and the e -Bird of Eutelsat company, as the main payload aboard the rocket. Originally SMART -1 should " screw " until March 2005 in a spiral path to the moon. However, since the ion drive worked better than expected by ESA scientists probe ever could swivel on the night of November 15, 2004 at a distance 5000-6000 km in an orbit around the moon.
Mission History
On 26 January 2005, the orbiter had started taking pictures of the lunar surface from a shallow orbit. Four weeks later, SMART-1 reached its highly elliptical orbit at a distance of 300 km from the South Pole and 3,000 km from the North Pole, and kept at this for 5 months. Due to the solid curve was announced in February 2005 by the ESA, the mission will be extended by one year. The end of the mission was set at the September 3, 2006 at 7:41 clock CEST. The unexpectedly large residual of the remaining fuel was used to orbit around a few kilometers to raise, so that the impact of the probe held on the near side of the moon, and as observed from the Earth and the spun-out material can be analyzed. In fact, the probe struck at exactly 07:42 clock and 22 seconds. The point of impact was in accordance with the lunar coordinate system exactly at 46.2 degrees West and 34.4 degrees south in the formation Lacus Excellentiae ( " Lake of Excellence ").
Technology
Construction
With the extended solar panel they had a wingspan of 14 meters, all other systems including drive and instruments were housed in a cube with side length of one meter. In developing the probe was very on the space-saving design of the individual systems. For example, was the X-ray telescope D- CIXS only 15 inches wide and weighed 5 kg. The probe had a launch mass of 367 kg ( including fuel ). 19 kg of which was attributable to the payload.
Drive
The energy for the novel ion thruster was generated with the help of solar cells. As fuel ( here called mass support ), the "Hall effect" drive uses an ionized noble gas (xenon ). While the engine is generated so that only a relatively small batch of 70 millinewtons, which is approximately the weight of a sheet of paper. For the xenon left the drive at tremendous speed, so that a high specific impulse arises. The fuel could be exploited as extremely efficient. Since an ion engine can accelerate as opposed to chemical engines, not only for minutes, but for months or even years, the achievable top speed is very high. Overall, this effective technique requires so much less support mass than a conventional chemical engine must be carried on fuel. This more scientific equipment could be integrated into SMART -1. On board were about 84 kg xenon ( in a 60 -liter pressure vessel ) and 19 kg of scientific instruments. SMART -1 used almost exclusively the ion thruster throughout the mission, launched in 1998, while the NASA probe Deep Space 1 is still used a conventional chemical engine to escape the gravitational field of the earth.
Navigation
The probe began a new navigation system called OBAN (OnBoard Autonomous Navigation ). This work completely autonomously, that it follows automatically a pre-programmed flight path. This is possible by placing the probe at a distance of two minutes each makes pictures of the Earth, the moon and the stars and compares them with each other. Thus, the probe could calculate their position in the room and automatically make course corrections. Through this system, a ground team that constantly takes over the navigation of the probe was not necessary. Thanks OBAN the ground station took only twice a week for eight hours each with the probe contact, this led to enormous cost savings in the ground teams.
Communication
Like the American Mars probe Mars Reconnaissance Orbiter (MRO ) continued SMART -1 trial basis, the new Ka-band for data transmission a. This uses frequencies in the range between 32 GHz and 34 GHz. Addition, however, the traditional X-band (7-8 GHz ) was operated. Since 2002, the ESA experimented with communication via laser in orbit. SMART - 1 resulted in a receiver for the laser link technology called with. Here, a 28 W strong laser pulse is emitted from a ground station on Tenerife of which was received by the probe. This conclusions were hoping to absorption and scattering of the signal at the Earth's atmosphere.
SMART -1 was the first spacecraft to turbo codes, a novel highly efficient error correction method, used for communication.
Experiments
The probe was different cameras for visible and invisible radiation. The experiment AMIE was an ultra-compact optical camera that recorded images of the moon. An infrared spectrometer ( SIR) has created a mineralogical map of the moon and the X-ray telescope D- CIXS was looking on the surface after the signature of water. Further experiments were concerned with the influence of the moon on the solar wind and with the X-ray activity of the sun.
Development
The probe was within - developed four years - in space rather short. The main contractor was the state company Swedish Space Corporation ( SSC ). The mission of SMART -1 cost 110 million euros, which is only about 20 percent of a typical European space mission. Modified copies of some instruments of SMART -1 started with the Indian lunar probe Chandrayaan -1.