Genesis was a NASA sample-return probe that collected a sample of solar wind particles and returned them to Earth for analysis. It was the first NASA sample-return mission to return material since the Apollo program, and the first to return material from beyond the orbit of the Moon. Genesis was launched on August 8, 2001, and the sample return capsule crash-landed in Utah on September 8, 2004, after a design flaw prevented the deployment of its drogue parachute. The crash contaminated many of the sample collectors. Although most were damaged, some of the collectors were successfully recovered. The Genesis science team demonstrated that some of the contamination could be removed or avoided, and that the solar wind particles could be analyzed using a variety of approaches, achieving all of the mission's major science objectives.
Objectives The mission's primary science objectives were:
To obtain precise solar isotopic abundances of ions in the solar wind, as essentially no data having a precision sufficient for solving planetary science problems are available; To obtain greatly improved solar elemental abundances by factor of 3–10 in accuracy over what is in the literature; To provide a reservoir of solar matter for 21st century science to be archived similarly as the lunar samples. Accordingly, in order to meet the mission science objectives, the Genesis spacecraft was designed to collect solar wind ions and return them to Earth for analysis. Genesis carried several different solar wind collectors, all of which passively collected solar wind; that is, the collectors sat in space facing the Sun, while the ions in the solar wind crashed into them at speeds over 200 km/s (120 mi/s) and, on impact, buried themselves in the surface of the collectors. This passive collection is a process similar to that used by the semi-conductor industry to make certain types of devices, and a simulation of the process is given by the free-access program SRIM. Most of the Genesis collectors continuously sampled all of the solar wind which the spacecraft encountered (the "bulk solar wind"). However, the spacecraft also carried three arrays of collectors which were deployed when specific "regimes" (fast, slow, coronal mass ejections) of solar wind were encountered, as determined by the electron and ion monitors on board. These deployable collector arrays were designed to provide data to test the hypothesis that the rock-forming elements keep their relative proportions throughout the processes which form the solar wind. There was a third type of collector on Genesis: the concentrator, which collected bulk solar wind, but was discriminating in that it electrostatically repelled hydrogen and had enough voltage to focus the lighter solar wind elements onto a small target, concentrating those ions by a factor of ~20. The objective of the concentrator was to bring back a sample with enhanced amounts of solar wind ions to make it possible for analysts to precisely measure the isotopes of the light elements.
Operation
Mission profile
Genesis was a Discovery-class mission of the NASA Jet Propulsion Laboratory (JPL) at the California Institute of Technology. The spacecraft was designed and built by Lockheed Martin Space Systems at a total mission cost of US$264 million. NASA launched the craft on a Delta II 7326 rocket on August 8, 2001, at 16:13:40 UTC from Cape Canaveral. The development of the trajectory for the mission was led by Martin Lo. Following launch, Genesis cruised to the Earth-Sun L1 then performed a Lissajous orbit insertion maneuver, entering an elliptical orbit about L1 on November 16, 2001. Genesis exposed its collector arrays on December 3, and began collecting solar wind particles. The collection process ended after 850 days, on April 1, 2004, with the spacecraft completing five halo loops around L1. Genesis began its return to Earth on April 22, 2004. The return phase included an orbital detour toward the Earth L2 so that the craft could be recovered during the daytime, as a direct approach would have forced it to be recovered at night. After completing one halo loop about L2, the Genesis sample return capsule separated from the spacecraft bus and returned to Earth for the planned recovery on September 8, 2004.
Recovery phase
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