Stardust (spacecraft)
Overview
The Stardust spacecraft was a NASA mission designed to collect samples from the comet Wild 2 and return them to Earth for analysis. Launched on February 7, 1999, Stardust was part of NASA's Discovery Program, which aims to conduct low-cost, highly focused planetary science investigations. The mission's primary objectives included the collection of cometary dust particles and interstellar dust, as well as the detailed imaging of the comet's nucleus.
Mission Objectives
Stardust's primary mission objectives were to:
- Collect samples of dust from the coma of comet Wild 2.
- Capture interstellar dust particles.
- Return the collected samples to Earth for detailed laboratory analysis.
- Image the nucleus of comet Wild 2 and study its structure and composition.
Spacecraft Design
The Stardust spacecraft was designed with several specialized instruments and features to achieve its mission objectives. Key components included:
- **Sample Return Capsule (SRC)**: The SRC was designed to safely return the collected samples to Earth. It was equipped with a heat shield to protect the samples during re-entry into Earth's atmosphere.
- **Aerogel Collector**: Stardust used a unique material called aerogel to capture dust particles. Aerogel is an extremely low-density solid that can slow down and trap particles without damaging them.
- **Navigation Camera**: The spacecraft was equipped with a navigation camera to help guide it to its target and capture images of the comet's nucleus.
- **Dust Flux Monitor**: This instrument measured the flux of dust particles encountered by the spacecraft.
Mission Timeline
Launch and Cruise Phase
Stardust was launched on February 7, 1999, aboard a Delta II rocket from Cape Canaveral Air Force Station. The spacecraft then entered a heliocentric orbit, where it would spend the next several years cruising towards its encounter with comet Wild 2.
Comet Encounter
On January 2, 2004, Stardust made its closest approach to comet Wild 2, passing within 240 kilometers of the nucleus. During this flyby, the spacecraft deployed its aerogel collector to capture dust particles from the comet's coma. The navigation camera captured detailed images of the comet's nucleus, revealing a complex and active surface.
Sample Return
After collecting the cometary dust samples, Stardust began its journey back to Earth. On January 15, 2006, the SRC separated from the main spacecraft and re-entered Earth's atmosphere. The capsule successfully landed in the Utah Test and Training Range, where it was recovered and transported to NASA's Johnson Space Center for analysis.
Scientific Findings
The analysis of the samples returned by Stardust provided valuable insights into the composition and structure of cometary and interstellar dust. Key findings included:
- **Organic Compounds**: The presence of complex organic compounds, including amino acids, was detected in the cometary dust samples. This finding supports the theory that comets may have played a role in delivering the building blocks of life to Earth.
- **Mineral Composition**: The samples contained a variety of minerals, including silicates and sulfides, which are thought to have formed in the early solar system.
- **Interstellar Dust**: The analysis of interstellar dust particles collected by Stardust provided new information about the composition and origins of these particles, which are thought to originate from outside our solar system.
Legacy and Impact
Stardust was the first mission to return samples from a comet to Earth, marking a significant milestone in planetary science. The mission's success demonstrated the feasibility of sample return missions and provided a wealth of scientific data that continues to be studied by researchers. The techniques and technologies developed for Stardust have also informed the design of subsequent missions, such as the OSIRIS-REx mission to asteroid Bennu.