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High-thrust electric propulsion reaching lofty milestones

Contact:
Pratt & Whitney Public Relations
UTC Chalet A420
Tel: 01-41-62-02-90

PARIS AIR SHOW---Le Bourget, France (June 17, 2003)— To meet the performance and financial needs of satellite manufacturers and better support emerging deep-space missions, Pratt & Whitney (P&W) Space Propulsion is aggressively developing its latest electric propulsion (EP) offering, the large, high-thrust Hall Effect Thruster (HET), known as the T-220HT.

This efficient and flexible propulsion system is intended to permit orbit transfer maneuvers in short amounts of time. It is an ideal size for orbit insertion and orbit transfer of large satellite systems. P&W has performed extensive testing at Edwards Air Force Base, University of Michigan, NASA Glenn Research Center (GRC) and Aerospace Corporation during the past two years and, to date, has demonstrated the following first-time HET test results:

* A narrow exhaust plume compared to other thrusters
* Successful 1,000 hour endurance tests of T-220 at 10 kilowatts (kW)
* Successful HET operation in the power range of 2–22 kW
* Thrust levels exceeding 1 Newton (N)
* Operation exceeding the orbit-raising requirement of 0.6 N/kW and thrust-per-unit power of 0.65–0.70 N/kW Specific impulse greater than 2,500 seconds
* Electromagnetic noise radiation (EMI) measurements 10–20 decibels (dB) under the MIL-STD 461C maximum noise curve in the frequency range of 200 MHz to 16 GHz (exception being ~5 dB over the curve at 1.2 GHz)
* No EMI emissions in the frequency range of 16–60 GHz.

Measurements during operation in vacuum chambers have demonstrated that the T-220HT has a narrow, well-collimated exhaust plume and exhibits among the best performance in electromagnetic interference testing ever measured. Low EMI is a key performance consideration for satellite designers.

"We have been able to achieve many great testing milestones with the T-220HT because of the outstanding heritage of the unit," P&W Space Propulsion and Russian Operations President Larry Knauer said. "The reproducible performance of the T-220HT, and its predecessor T-220, has shown that this thruster works well in producing the required thrust and specific impulse to support satellite operations."

The T-220HT is a derivative of the base T-220, which was built and delivered to NASA GRC in 2000. NASA GRC carried out an endurance test of the T-220 for 1,000 hours at a power level of 10 kW. There was no performance degradation of the thruster during the 1,000-hour run, and the very low observed erosion rate suggests a long operational lifetime is likely.

"Although EP-driven spacecraft have very low thrust rates, they can achieve a large total impulse by thrusting for long periods (months or even years) with propellant consumption rates that are five to 10 times better than those of chemical rockets," Knauer added. "This can translate into significant mass savings that can enable larger useful payloads and/or lower launch costs."

In the summer of 2000, P&W took a giant step toward harvesting the technology behind EP when it acquired Space Power, Inc. (SPI), a U.S. company that designed and patented EP systems.

P&W Space Propulsion currently offers three HET engines developed by SPI: the T-40, T-140 and T-220. Their nominal power levels are 200 watts, 3.5 kilowatts and 10 kilowatts respectively. The T-40 is suitable for small satellite applications, the T-140 for low earth orbit systems and station keeping, and the T-220 for large spacecraft and deep space missions. P&W Space Propulsion also designs and builds the power processing units (PPUs) that convert electric energy from satellite solar panels into electric power to drive and control the HETs.

P&W Space Propulsion, a leader in liquid, solid, electric and hypersonic propulsion, has sites located at West Palm Beach, Fla. and San Jose, Calif., United States. P&W's web site address is www.pw.utc.com P&W, a United Technologies company (NYSE: UTX), is a world leader in the design, manufacture and service of aircraft engines, space propulsion systems and industrial gas turbines.

NOTE TO EDITORS: A complete description of the recent T-220HT testing will be given in a paper, "CHARACTERISTICS OF THE T-220HT HALL EFFECT THRUSTER" at the 39th Joint Propulsion Conference in Huntsville, Ala., U.S.A., 20-23 July.

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