Collecting Solar Wind

Genesis opened its collector arrays and began accepting particles of solar wind on Dec. 3, 2001. A total of 850 days were logged exposing the special collector arrays to the solar wind. These collector arrays are circular trays composed of palm-sized hexagonal tiles made of various high-purity materials such as silicon, sapphire, gold and diamond-like carbon.

After the sample return capsule opened, the lid of the science canister opened as well, exposing a collector for the bulk solar wind. As long as the science canister's lid was opened, this bulk collector array was exposed to different types of solar wind that whistled past the spacecraft.

Genesis' ion and electron monitors, located on the equipment deck outside the science canister and sample return capsule, monitored changes in the solar wind. The monitors relayed information about these changes to the main spacecraft computer, which in turn commanded the collector arrays to change to expose the appropriate collector.

The monitors distinguished between three types of solar wind — fast, slow and coronal mass ejections — by recognizing the wind's characteristic temperature, velocity, density and composition. There were three collector arrays that folded out, and each was extended when a certain type of solar wind passed by.

Genesis' other dedicated science instrument, the solar wind concentrator, was designed to do exactly as its name implies, concentrate the solar wind onto a set of small collector tiles made of diamond, silicon carbide and diamond-like carbon. The concentrator was exposed to the solar wind throughout the collection period, as long as the lid of the science canister was opened.

That collection of pristine particles of the Sun came to an end on April 1, 2004, when the Genesis team ordered the spacecraft's collectors stowed. The closeout process was completed on April 2, when Genesis closed and sealed the spacecraft's sample return capsule. The capsule will remain sealed until NASA technicians open it in a temporary clean-room facility at Dugway, Utah. The canister will then be removed and transported to NASA's Johnson Space Center, where the materials it contains will be removed in a state-of-the art clean room installed specifically for Genesis.