The Peregrine Sounding Rocket Program is a joint basic research program of NASA Ames Research Center, NASA Wallops, Stanford University, and the Space Propulsion Group, Inc. (SPG). The goal is to determine the applicability of this technology to a small launch system. The approach is to design, build, and fly a stable, efficient liquefying fuel hybrid rocket vehicle to an altitude of 100 km. The program was kicked off in October of 2006 and has seen considerable progress in the subsequent 18 months.

Within this period significant progress was made, including:

• Successfully completed Conceptual Design Review (CoDR) and Prelimi nary Design Review (PDR) for flight vehicle capable of 100-km altitude;
• Designed and fabricated flight-weight combustion chamber, main oxidizer valve, throttle system, and thrust structure;
• Successfully completed CoDR, preliminary design review (PDR), Critical Design Review (CDR), and Integrated Test Readiness Review (ITRR) for ground test facility at NASA Ames Research Center;
• Completed subsystem testing for flight weight main oxidizer valve, throttle system, helium pressurization system, ignition system, and thrust structure;
• Completed facility integrated test series including five cold-flow tests, two with live igniters, and three hotfire tests;
• Successfully fired motor ten times, including one full duration burn during 1st phase of ground testing.

While this was a significant progress by any measure, the project suffered a schedule setback due to the July 2007 explosion at the Scaled Composites test site involving nitrous oxide. A thorough review of the system design and nitrous oxide operational procedures was undertaken and several changes have been implemented to increase human safety.

This research group began studying liquifying hybrid rocket fuel technology more than a decade ago. The overall goal of the research was to gain a better understanding of the fundamental physics of the liquid layer entrainment process responsible for the large increase in regression rate observed in these fuels, and to demonstrate the effect of increased regression rate on hybrid rocket motor performance. At the time of this reporting, more than 400 motor tests were conducted with a variety of oxidizers (N2O, GOx, LOx) at ever increasing scales with thrust levels from 5 to over 15,000 pounds (22 N to over 66 kN) in order to move this technology from the laboratory to practical applications.

The Peregrine program is the natural next step in this development. A number of small sounding rockets with diameters of 3, 4, and 6 in. (7.6, 10.2, and 15.2 cm) have been flown, but Peregrine at a diameter of 15 in. (38.1 cm) and 14,000-lb (62.3-kN) thrust is by far the largest system ever attempted and will be one of the largest hybrids ever flown. Successful Peregrine flights will set the stage for a wide range of applications of this technology. The metrics of the program are:

• Demonstrate satisfactory motor performance in ground test.
• Demonstrate motor throttling in ground test.
• Fabricate the sounding rocket system, transport it to the NASA Wallops facility, and launch a payload to 100 km using paraffin and N2O as the propellants.
• Demonstrate operational efficiency at the Wallops launch site.

This work was done by Gregory Zilliac of Ames Research Center.

Inquiries concerning rights for commercial use of this invention should be addressed to the Ames Technology Partnerships Division at (650) 604-5761. ARC-16240-1

NASA Tech Briefs Magazine

This article first appeared in the January, 2012 issue of NASA Tech Briefs Magazine.

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