Launching Aspects of the Mission

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A quick time video animation of the solar panels deploying can be seen here.(low resolution (532 K) high resolution (1 M))

A quick time video animation of the launch can be seen here. (low resolution (852 K) high resolution (2 M))

The NEAR spacecraft launched on February 17, 1996 at the Cape Canaveral Air Force Station in Florida. A Delta II rocket propelled the spacecraft into orbit. Delta is a family of two- to three-stage liquid propelled launch vehicles. The Delta II is capable of placing a spacecraft and its payload of up to 2200 kg in a low equatorial orbit. The Delta II is a relatively small and inexpensive rocket used for launching.

The NEAR spacecraft will follow a Delta VEGA trajectory. The trajectory is the part of the orbit that gets the spacecraft to its destination. "Delta V" stands for a change in velocity, which occurs many times throughout the mission, and "EGA" means Earth Gravity Assist. The diagram above shows NEAR's trajectory profile and lists dates of key mission events. Today's trajectory is shown on the official JHU-APL NEAR web site.

In June of 1997 NEAR will fly by of the C-type asteroid 253 Mathilde (discovered in 1885). These will be the first close-up images of this type of asteroid. It should also be noted that observational data from Earth-based radar and telescopes revealed that Mathilde is 61 km in diameter, which is significantly larger than either of the Galileo-observed S-type asteroids, 951 Gaspra (16 km) and 243 Ida (33 km). A few days after the flyby of Mathilde, a deep space maneuver will be performed which will, in a sense, bring the craft back around to swing by Earth for its gravity assist. The assist will bend the craft's trajectory so that it is put into the orbital plane of 433 Eros. This planned gravity assist allowed use of a smaller, less expensive rocket.

In January, 1999 several more rendezvous maneuvers will take place to slow the spacecraft down to a velocity nearly identical to Eros. This will then enable the spacecraft to insert itself into orbit around Eros. From that point on, NEAR's instrumentation payload goes into action, and the one year study of Eros begins.

This mission will accomplish a number of "firsts" in space exploration including:

• First spacecraft to orbit a small body.
• First detailed exploration of a near-Earth asteroid.
• First close-up images of a C-type asteroid.
• First planetary mission for the Delta launch vehicle.
• First time that a spacecraft powered by solar cells has operated beyond Mars' orbit.
• First spacecraft visit to an asteroid the size of Mathilde.

Lesson Plan on Aspects of Launching a Spacecraft

Lesson Plan on Vector Addition

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Contact Steve Bowser (slbowser@umd5.umd.edu) or Joy Maloney (jmaloney@umd5.umd.edu) for further information.