Tag Archives: ion engines

Dawn’s chief engineer reviews the mission

In a long and very detailed post, the chief engineer and mission director of Dawn gives us a very detailed update on the successful state of the spacecraft’s mission.

Not only does he describe what has been gathered at Ceres since the spacecraft arrived a year ago, he gives us this crucial information about the state of this paradigm-shattering ion engine spacecraft, the first to travel to two different objects in the solar system:

Dawn has faced many challenges in its unique voyage in the forbidding depths of space, but it has surmounted all of them. It has even overcome the dire threat posed by the loss of two reaction wheels (the second failure occurring in orbit around Vesta 3.5 years and 1.3 billion miles, or 2.0 billion kilometers, ago). With only two operable reaction wheels (and those no longer trustworthy), the ship’s remaining lifetime is very limited.

A year ago, the team couldn’t count on Dawn even having enough hydrazine to last beyond next month. But the creative methods of conserving that precious resource have proved to be quite efficacious, and the reliable explorer still has enough hydrazine to continue to return bonus data for a while longer. Now it seems highly likely that the spacecraft will keep functioning through the scheduled end of its primary mission on June 30, 2016.

NASA may choose to continue the mission even after that. Such decisions are difficult, as there is literally an entire universe full of interesting subjects to study, but resources are more limited. In any case, even if NASA extended the mission, and even if the two wheels operated without faltering, and even if the intensive campaign of investigating Ceres executed flawlessly, losing not an ounce (or even a gram) of hydrazine to the kinds of glitches that can occur in such a complex undertaking, the hydrazine would be exhausted early in 2017. Clearly an earlier termination remains quite possible.

Dawn has proven the value of ion engines. I would expect to see them used many more times in the future, especially missions heading to low gravity environments.

NASA contracting development of new ion/nuclear engines

The competition heats up: NASA has awarded three different companies contracts to develop advanced ion and nuclear propulsion systems for future interplanetary missions, both manned and unmanned.

These are development contacts, all below $10 million. However, they all appeared structured like NASA’s cargo and crew contracts for ISS, where the contractor does all of the development and design, with NASA only supplying some support and periodic payments when the contractor achieves agreed-upon milestones. Because of this, the contractors will own the engines their develop, and will be able to sell them to other customers after development, thereby increasing the competition and innovation in the field.

NASA considering ion engines for next Mars orbiter

Rather than using conventional chemical thrusters for a Mars orbiter planned for the 2020s, NASA managers are considering using ion engines instead.

Worried its fleet of Mars orbiter is aging, NASA intends to dispatch the spacecraft to the red planet in September 2022 to link ground controllers with rovers and extend mapping capabilities expected to be lost when the Mars Reconnaissance Orbiter stops functioning.

Engineers also want to add ion engines to the orbiter and fly the efficient electrically-powered thruster system to Mars for the first time, testing out a solar-electric propulsion package that officials say will be needed when astronauts visit the red planet. Ion engines produce just a whisper of thrust, using electric power to ionize atoms of a neutral gas and spit out the particles at high speed. While the drive given by the thrusters is barely noticeable in one instant, they can operate for months or years, burning scant fuel compared to traditional chemical rockets.

That this decision requires long-winded and extended high level negotiations at NASA illustrates the slow and lumbering nature of government. Private enterprise is embracing ion engines now, and NASA itself is seeing its own spectacular ion engine success with Dawn. The decision should be a no-brainer, especially because the benefits of ion engines (low weight, more power, greater flexibility) are so obvious.