NASA Pathfinder

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NASA's Pathfinder and Helios were a series of solar- and fuel cell system-powered unmanned aircraft. AeroVironment, Inc. developed the vehicle under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program.

Contents 1 Design 2 Pathfinder operations 3 Significance and goals 4 References 5 External links 6 Media 7 See also

[edit] Design

Sunnyvale, California-based Sunpower Corporation supplied solar cells for Helios. The cells featured a rear-contact cell design that placed wires on the underside of the cells, so as not to obstruct the cells' exposure to solar radiation.

The fuel cell systems designed for the Helios Prototype included both regenerative and non-regenerative designs.

[edit] Pathfinder operations

On 13 August, 2001, it set an unofficial world record for sustained altitude by a winged aircraft. It sustained flight at above 96,000 feet (29,250 m) for forty minutes, and at one time it flew as high as 96,863 feet (29,524 m). Later, in June 2003, the prototype broke up and fell into the Pacific Ocean about ten miles (16 km) west of the Hawaiian Island Kauai.

[edit] Significance and goals

NASA claimed that if the concept the prototype embodied proved itself, then multi-month flight would become feasible. Accordingly, Helios was a forerunner of what some call artificial "atmospheric satellites". NASA claimed such atmospheric satellites might someday replace conventional artificial satellites.^{[citation needed]}

NASA established two major goals for the Pathfinder:

• Reach an altitude at or near 100,000 feet (30 km) with a small payload on a single-day flight. NASA could apply the knowledge gained therein firstly to carry scientific instruments to high altitudes, and secondly when designing aircraft for, or completing missions on, Mars. NASA claimed that a vehicle so capable could also carry larger payloads to lower altitudes. This versatility would enhance the Prototype's worth.
• Achieve extreme duration. Initially, plans called for the aircraft to maintain, by the year 2003, flight for ninety-six uninterrupted hours, most of which would have occurred at an altitude greater than 50,000 feet (15,000 meters). Later, NASA delayed those plans by three years. Meanwhile, it sought to maintain, by September 2003, flight for forty hours, with at least fourteen of those hours above 50,000 feet (15,000 m).

[edit] References

• Current Projects - Helios Prototype
• NASA Dryden Fact Sheets - Helios Prototype
• "Photovoltaic Finesse: Better Solar Cells—with Wires Where the Sun Don't Shine", an article by Daniel Cho on page thirty-three of the September, 2003 issue of Scientific American

[edit] External links

• NASA's Helios Project
• Helios for kids.

[edit] Media

[edit] See also

• Electric vehicle