The significant astronomical aspect that was chosen for discussion in this essay is the NEAR Shoemaker landing on Asteroid Eros. NEAR is the acronym for The Near Earth Asteroid Rendezvous and was named in the honor of Gene Shoemaker, one of the most renowned planetary scientist. This project was actually planned for studying the 422 Eros, the near earth Asteroid. 422 Eros is one of the largest asteroids of near Earth.
This astronomical operation was the first mission to orbit an asteroid and also the first to land on an asteroid’s surface. The fundamental scientific goals of this mission were to gather and track data related to the majority properties, configuration, mineralogy, morphology, and the internal distribution of mass as well as the magnetic field of Eros. In addition, that other supplementary goals of this project were to explore the regolith properties, connections with the solar airstream, likely activities of the current because of dust and/or gas, and lastly the spin state of the asteroid.
The NEAR spaceship was armed with an “X-ray/gamma ray spectrometer, a near infrared imaging spectrometer, a multi-spectral camera fitted with a CCD imaging detector, a laser rangefinder, and a magnetometer.” In addition to all the above, there was also a radio science experiment that was carried out with the help of the tracking system instilled in the NEAR for estimating the magnitude and enormity of the asteroid while also ascertain the asteroid’s mass and thickness.
This asteroid was launched in the year 1996, precisely on the 17th of February. As already mentioned above, this mission was the first to be launched and was also part of the low-cost science missions carried out by NASA. This asteroid had apparently believed to have deviated away from the main asteroid belt that actually orbits Sun and lies between the planets Mars and Jupiter.
After its launch in the year 1996, the NEAR asteroid travelled to the Mathilde asteroid for a flyby, before finally landing on Asteroid 433 Eros on the 12 of February, 2001. In this process, the spaceship transmitted roughly about 69 close-up images of Eros 433’s surface during the course of its final landing. This first ever mission of NASA was actually created specifically for studying an asteroid.
The rotation axis of 433 Eros is known to be in alignment with the Sun-Eros line. The south pole of the asteroid was in the direct of the Sun and this further translates to the fact that the northern hemisphere of it is actually shadowed. In the case of NEAR Earth spaceship’s orbit, the last two months of the orbit’s phase, the orbit of the spaceship was rearward and roughly equatorial. Prior to this, the rotation axis of the asteroid was approximately vertical to the Sun-Eros line, and the spaceship orbit was roughly polar. This was the geometry that was successfully prevalent between the months of May and August of the year 2000.
The entire mission of the NEAR Shoemaker spanned for a period of half a decade and this started with its launch from the Earth’s surface and its final descent on the surface of 433 Eros. At the time of its encounter with Eros, the spaceship was roughly 160 million miles away from Earth. In scientific terms, the same can be stated as being 1.7 astronomical units (AU), wherein one astronomical unit is equal to 93 million miles of average distance between the Sun and the Earth.
When NEAR space craft finally descended on 433 Eros, it was believed to have traversed a distance of approximately 2.3 billion miles round the Sun, which also comprises of the 417 million miles journeyed during the year-long orbit of the spaceship around Eros. By this time, Eros 433 was about 197 million miles away from the Earth’s surface, which is marginally more than 2.11 AU to be precise. Actually, the NEAR spaceship was very close to the Sun, which was actually 133 million miles or scientifically 1.43 AU far from the asteroid.
Between the 14th of February, 2000, to the 12th of February, 2001, the spacecraft surrounding the Eros for roughly 230 times at different expanses. The spacecraft expended more than 100 of days of the total orbit of 31 miles from the epicenter of Eros. Often, this orbit also extended to approximately 200 miles. “A low-altitude pass on Oct. 26, 2000, brought it to within 3 miles of the surface. After that, the probe headed back out to 125 miles for global observations.” Finally, in the month of December 2000, the spacecraft landed on Eros to 22 miles and functioned at almost the same distance for the remaining period of the mission. The NEAR spaceship clicked about 160,000 pictures while orbiting the Eros Asteroid. The fundamental motive to study Asteroid Eros was because it is quite big and possibly also the closest asteroid to Earth, with a mass that is several thousand times greater than that of any other asteroids that are akin to it.
Works Cited
Cheng, Andrew F. "Near Earth Asteroid Rendezvous: Mission Summary." Asteroids III (2005): 351-366. Web. 27 March 2016. <http://thelivingmoon.com/20UMLR/05pdf/Near_Earth_Asteroid_Rendezvous_Mission_Summary_Cheng.pdf>.
NASA (National Aeronautics and Space Administration). NEAR -Shoemaker. 1996. Web. 27 March 2016. <http://science.nasa.gov/missions/near/>.
Space Today Online. NEAR-Shoemaker Lands on Asteroid Eros. 2002. Web. 24 March 2016. <http://www.spacetoday.org/SolSys/Asteroids/NEAR.html>.
