The future is here for spacecraft propulsion and the trouble-free engine
performance that every vehicle operator would like to see, achieved by an
ion engine running for a record 30,352 hours at NASA’s Jet Propulsion
Laboratory, Pasadena, Calif.

The engine is a spare of the Deep Space 1 ion engine used during a
successful technology demonstration mission that featured a bonus visit to
comet Borrelly. It had a design life of 8,000 hours, but researchers kept it
running for almost 5 years — from Oct. 5, 1998, to June 26, 2003 — in a
rare opportunity to fully observe its performance and wear at different
power levels throughout the test. This information is vital to future
missions that will use ion propulsion, as well as to current research
efforts to develop improved ion thrusters.

“Finding new means to explore our solar system — rapidly, safely and with
the highest possible return on investment — is a key NASA mission,” said
Colleen Hartman, head of Solar System Exploration at NASA Headquarters,
Washington, D.C. “Robust in-space flight technologies such as ion propulsion
are critical to this effort and will pioneer a new generation of discovery
among our neighboring worlds.”

While the engine had not yet reached the end of its life, the decision was
made to terminate the test because near-term NASA missions using ion
propulsion needed analysis data that required inspection of the different
engine components. In particular, the inspection of the thruster’s discharge
chamber, where xenon gas is ionized, is critical for mission designers of
the upcoming Dawn mission. Dawn, part of NASA’s Discovery Program, will be
launched in 2006 to orbit Vesta and Ceres, two of the largest asteroids in
the solar system.

“The chamber was in good condition,” said John Brophy, JPL’s project element
manager for the Dawn ion propulsion system. “Most of the components showed
wear, but nothing that would have caused near-term failure.”

Marc Rayman, former Deep Space 1 project manager, said, “There are many
exciting missions into the solar system that would be unaffordable or truly
impossible without ion propulsion. This remarkable test shows that the
thrusters have the staying power for long duration missions.”

Ion engines use xenon, the same gas used in photo flash tubes, plasma
televisions and some automobile headlights. Deep Space 1 featured the first
use of an ion engine as the primary method of propulsion on a NASA
spacecraft. That engine was operated for 16,265 hours, the record for
operating any propulsion system in space. Ion propulsion systems can be very
lightweight, because they can run on just a few grams of xenon gas a day.
While the thrust exerted by the engine is quite gentle, its fuel efficiency
can reduce trip times and lower launch vehicle costs. This makes it an
attractive propulsion system choice for future deep space missions.

“The engine remained under vacuum for the entire test, setting a new record
in ion engine endurance testing, a true testament to the tremendous effort
and skill of the entire team,” said Anita Sengupta, staff engineer in JPL’s
Advanced Propulsion Technology Group. “This unique scientific opportunity
benefits current and potential programs.”

“The dedicated work of NASA’s Solar Electric Technology Application
Readiness test team, led by JPL, continues to exemplify a commitment to
engineering excellence,” said Les Johnson, who leads the In-Space Propulsion
Program at NASA’s Marshall Space Flight Center, Huntsville, Ala. “This work,
along with significant contributions from NASA’s Glenn Research Center in
Cleveland, will take NASA’s space exploration to the next level.”

NASA’s next-generation ion propulsion efforts are led by the In-Space
Propulsion Program, managed by the Office of Space Science at NASA
Headquarters and implemented by the Marshall Center. The program seeks to
develop advanced propulsion technologies that will help near and mid-term
NASA science missions by significantly reducing cost, mass or travel times.

The Jet Propulsion Laboratory is managed for NASA by the California
Institute of Technology, Pasadena, Calif.