Explorer 1, the first successful satellite sent to space

EXPLORER 1

THE FIRST SUCCESFUL SATELLITE SENT TO SPACE

Today I will present you the American satellite Explorer I and how it has been developed and put in orbit. So first I will explain the context and the project development and then all the technical characteristics of this satellite.

The beginning and the choice of the launcher: The launch of a satellite is initially scheduled for 1957-1958. But this objective became a national issue when the Soviet Union managed to overtake the US by putting, he first artificial satellite sputnik 1 into orbit on the 4th October 1957.On top of that problems of development delayed the first flight of the American launcher Vanguard designated for this launch in 1955. So, engineers working at the Army ballistic missile agency and the jet propulsion Laboratory took up the challenge by developing both the launcher and the satellite in less than 90 days. The Juno I launcher is tasked with taking on the Soviet challenge by replacing the Vanguard launcher on the Spot whose development was not yet complete. On its first attempt on the 1st February 1958 the launch vehicle I placed the first American satellite Explorer 1 in orbit from the Cape Canaveral launch base in Florida.

The launch and the conduct of the mission: However, it is expected that the press conference will only be convened if the launch is successful. According to the calculations, the radio signal to be emitted by the satellite in case of success must be detected 106 minutes after the launch vehicle takes off. But after the 106th minute no signal is received. The minutes pass and the tension rise when finally, at the 114th minute, the station received a strong signal signifying the success of the launch. The explanation is that the launcher is more efficient than expected and places the satellite in higher orbit.

Explorer 1 transmitted data for 111 days until its batteries were exhausted, which interrupted exchanges on the 23 May 1958. Then the satellite remained in orbit for more than 12 years before it penetrated the atmosphere and consumed.

So now I will focus on the technical characteristics of the satellites. First, the tools used: James Van Allen a scientist of the University of Iowa is responsible for the design of the on-board scientific instrumentation which is consist of:

- A Geiger-muller to detect cosmic rays (cosmic radiation is the flow of atomic nuclei and high energy particles circulating in the interstellar middle)

- 5 temperature sensors (one internal, three external and one in the cap)

- Micrometeorite detectors

Then with these tools they got some result: The Geiger meters detected radiation considered to be in line with predictions made before the flight on part of his orbit but on other parts of the orbit no radiation was detected. No explanation was found, especially on this first satellite there is no recording system and the scientific data is transmitted in real time to earth. They don’t know how to interpret this data. The mystery is solved with the discovery of the doughnut shaped Van Allen belt as part of the Explorer III mission. Van Allen belts are toroidal zone of the earth magnetosphere that surround the magnetic equator. It consists of two distinct zones called “inner belt” and “outer belt”. The first,

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