Exploring the Planets

Exploration of Asteroids

NEAR Shoemaker (Near Earth Asteroid Rendezvous)

NEAR Shoemaker is the first spacecraft mission specifically designed to study an asteroid. It was launched on February 17, 1996 on a four-year journey to the Near-Earth asteroid 433 Eros. Originally only named NEAR, the spacecraft was renamed after arriving at the asteroid, in honor of the late Eugene Shoemaker, a renowned planetary scientist.

The objective of the mission was to encounter and orbit Eros for one year to collect imagery and gather data on the asteroid's properties such as surface features, composition, and rotation. During its orbit of Eros, NEAR Shoemaker imaged the asteroid from altitudes ranging from 320 kilometers (200 miles) to as low as 5 kilometers (3 miles). The mission was successfully completed in February 2001 when a previously unplanned landing was executed. This was the first time a spacecraft ever landed on an asteroid.

On its way to Eros, NEAR encountered asteroid 253 Mathilde on June 27, 1997. The image at right is a mosaic of four images returned by the NEAR spacecraft when it was 2,400 kilometers (1,500 miles) from Mathilde.

For more information, see the NEAR Mission Home Page (APL).

Images of 433 Eros from NEAR Shoemaker

Two days after NEAR Shoemaker began its orbit of Eros, the spacecraft captured this rotation movie as it moved closer to the asteroid. The movie shows a full rotation on February 16, 2000, as viewed from a range of about 340 kilometers (211 miles).

433 Eros

Four images have been mosaicked together to produce this view of 433 Eros. A boulder the size of a house can be seen on the floor of the large 6-kilometer (4-mile) crater.

Composite Eros Image from NEAR Mission

These views of 433 Eros from different angles illustrate how its surface has been bombarded by numerous meteoroid impacts.

433 Eros

The last image of 433 Eros sent back from NEAR Shoemaker before it landed. The image was taken from an altitude of only 120 meters (390 feet). The boulder at the top is about 4 meters (12 feet) across.

For more information, see the NEAR Mission Home Page (APL).

 

NEAR-Shoemaker

NEAR Shoemaker Spacecraft
(NASA artist rendition)

Asteroid Mathilde

The image shows Mathilde has had a history of violent impacts. A large crater estimated to be nearly 10 kilometers (6 miles) deep is hidden in shadow at center. The jagged edge at the upper left limb of the asteroid is the rim of another large crater viewed edge on. The portion of Mathilde visible in this image measures roughly 59 by 47 kilometers (36 by 29 miles).

Hayabusa

In 2005, the Haybusa spacecraft from the Japanese Space Agency (JAXA) arrived at the asteroid Itokawa. After a failed first attempt, Hayabusa landed on the asteroid, collected a small sample and took off again. It was the first spacecraft to perform such a maneuver. Studies of the samples are increasing our knowledge about the composition and weathering of the stony class of asteroids.

 

 

Artist's Concept of the Hyabusa (Muses-C) Spacecraft

Hayabusa.

 

Itokawa

Itokawa. Credit: JAXA/A. Ikeshita/MEF.

Dawn

The Dawn spacecraft used ion propulsion to travel to Vesta, the second most massive object in the asteroid belt. Having arrived in July 2011, its mission was to explore Vesta for a year and then travel to Ceres, the largest asteroid in the belt. Dawn arrived at Ceres in March 2015.

Vesta's south pole is characterized by a tall mound inside a large depression. NASA/JPL-Caltech/ UCLA/MPS/DLR/IDA

Large grooves at Vesta's equator may be related to south pole impacts. NASA/JPL-Caltech/ UCLA/MPS/DLR/IDA

 

Dawn spacecraft

Dawn.

Mountain on Ceres

Mountain on Ceres

 

South Pole of the Asteroid Vesta

Vesta's south pole.

Vesta

Vesta's equator.

Future Mission

OSIRIS-REx (the Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer!) is a NASA New Frontiers mission that will study and sample the Near-Earth Asteroid 1999 RQ36. Launch is planned for 2016, with a three-year cruise to the asteroid. The spacecraft will spend about a year studying RQ36 and will use a robot arm to collect a sample to be returned to Earth in 2023. OSIRIS-REx hopes to answer questions about the early formation of our solar system and to improve our ability to predict the paths of asteroids that travel near to Earth.

 

OSIRIS-REx

Simulated image of asteroid 1999 RQ36 compiled from topographic and radar data. RQ36, 580 meters (1900 feet) in diameter, is a primitive body likely formed in the earliest days of our solar system. Image courtesy of NASA/GSFC/UA.

Asteroid 1999 RQ36