NEAR Voyage 4: Cruising in Space

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Cruising in Space: February 1996 - June 1997

NEAR's first months in space were devoted to verifying the health and function of the onboard systems. Engineers turned on the instruments and returned data to Earth. Less than three days after launch, the multispectral imager was turned on to take pictures of the Moon some 2.9 million kilometers (1.8 million miles) away!

Earth's Moon, imaged from NEAR at a range of 2.9 million
kilometers (1.8 million miles), on February 21, 1996.

In order to get to Eros using a launch vehicle as small as a Delta, NEAR has followed a long, roundabout trajectory. Nearly two years after launch, the spacecraft was flown close by Earth to get a boost in velocity from the Earth's gravity, similar to a slingshot. The extra velocity gained by this Earth "Swingby" avoided the need for a much larger, much more expensive rocket (launch vehicle).

NEAR's trajectory to Eros

A direct shot from Earth to Eros would take about one year, but his roundabout trajectory took nearly three years. That extra time was a bonus to mission engineers, planners, and scientists, because it provided opportunities to practice using the spacecraft and instruments and to fully characterize their performance in preparation for operations at Eros.

For example, just five weeks after launch, NEAR performed its first complicated series of turns to acquire images of Comet Hyukatake, some tens of millions of miles distant. And in the following months, the imager took pictures of a variety of stars and star clusters to characterize its response and performance in the harsh conditions of space.

The following images were taken to characterize the photometric response of the camera, its focus parameters and the exact size of it’s field of view. We also practiced receiving the data on the ground, transferring it to APL and the NEAR Science Data Center while scientists tested their data processing software.

The inner coma of Comet Hyakutake, imaged from NEAR
on March 24, 1996. Stars in the background are named.

The Beehive Cluster (Praesepe), imaged from NEAR on May 2, 1996.

The Pleiades star cluster imaged from NEAR on January 15, 1997

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