|
NEAR Mission Launch and Early Procedures The Near Earth Asteroid Rendezvous (NEAR) spacecrafts was designed with specific hopes of accomplishing close up studies of asteroids located near Earth’s orbit. It was designed, built and funded by John Hopkins University Applied Physics Laboratory (APL), who also managed the mission for NASA, in Laurel, Maryland. At this time, APL was striving to create planetary missions that would cost a maximum of 150 million dollars for construction, launch and a 3-year mission. NEAR was the first launch in APL’s new cost effective program; therefore time was a major factor in both designing and constructing the spacecraft. Near was built in only 26 months, with each piece first being assembled and tested in 1994 to early 1995, then the whole spacecrafts being organized and checked for tribulations in late 1995. The NEAR spacecraft arrived at the Kennedy Space Center one month ahead of schedule, in February of 1996. NEAR is roughly the size of a car, at 1775 pounds (at launch time) and 9’2” long, including the antenna. Since NEAR was built with simplicity in mind, engineers placed its antenna, solar panels and 6 instruments right on the spacecraft’s body. This ensured a quicker construction time, yet made it harder to operate the machine. The antenna is 5 foot in diameter and is located right on top of the spacecraft. The 4 solar panels are each 18 squared feet and powered at 1800 W @ 1 AU. The six instruments placed on NEAR are the most important parts of its structure, as far as the goals of the mission are concerned. They are as follows: ~Magnetometer (MAG)- used to look for and map out any magnetic fields on the asteroids. It has an interior calibration coil that can be implemented on command from Earth (NASA). ~Multi-spectral Image (MSI)- (an electrical camera) used to provide infrared and visible images of the asteroids shape and surface features, including any mineral distributions. It gives a 10 x 16 m resolution at 100 km. ~NEAR Laser Rangefinder (NLR)- used to scan the precise shape of the asteroid, giving a topographical outline and global replica of the asteroid. During testing, the resolution was better than 0.5 m. ~NEAR Infrared Spectrometer (NIS)- used to determine the mineral composition and abundance of minerals on the surface of the asteroid. ~Radio Science- an X-band transponder used to measure the asteroids mass and gravitational field, and let us know NEAR’s location and velocity in space. ~X-Ray/ Gamma Ray Spectrometer (XGRS)- actually two different instruments. The X-Ray is used to measure, of course, x-rays on the asteroids created by solar flare x-rays using gas-filled counters. The Gamma Ray is a scintillator and shield used to detect gamma rays coming off of the asteroids surface between 0.3 to 10 MeV. Overall, it measures for chemicals such as Silicon, Magnesium and Iron.
|
9 views of Eros
|
Eros