GAO: NASA Asteroid Impact Mission Faces Technical, Schedule Challenges

DART spacecraft (Credit: JHU APL)

by Douglas Messier
Managing Editor

NASA’s ambitious effort to redirect a small asteroid has run into challenges with its financing, technology and foreign partner that could delay its launch and reduce its scientific return, according to a new assessment by the Government Accountability Office (GAO).

The Double Asteroid Redirection Test (DART) will impact the smaller of the binary near-Earth asteroid Didymos. Scientists will study how the asteroid is deflected to learn how similar systems might be used on potentially hazardous near-Earth objects.

NASA hopes to launch DART between December 2020 and May 2021, but the flight could slip significantly depending upon funding.

“Project officials told us that if they receive less funding than planned, there is another launch opportunity 2 years later and they are currently studying the effects on the mission if it is delayed to this date,” the GAO report stated. “Officials also noted a delayed launch window would likely increase total costs in exchange for lower annual costs.”

A key challenge is the mission’s use of NASA’s Evolutionary Xenon Thruster-Commercial (NEXT-C), a new technology that will be tested in space for the first time.

“However, first-time production of this system—DART’s critical path and top risk—is proving challenging,” the assessment found. “The NEXT-C thruster’s power processing unit, which provides necessary voltages to the thruster, is the technical risk keeping the thruster from maturing.”

The mission was thrown a curve when the European Space Agency failed to fund DART’s sister project, the Asteroid Impact Monitor (AIM) spacecraft. AIM was to have collected data along with Earth-based telescopes as the DART spacecraft impacted the smaller Didymos asteroid.

“While the project believes that it can still meet its objectives of characterizing the results of the DART impact on the Didymos system, the project is performing planning and analysis leading up to preliminary design review to determine how effective the Earth-based observatories will be at determining the results of the impact event,” the report stated. “As a result of the potential loss of science data, NASA is considering possible alternatives that could provide imagery and data related to the impact.”

The GAO’s assessment is below.

NASA: Assessments of Major Projects
Government Accountability Office
May 1, 2018
Full Report

Double Asteroid Redirection Test

The DART project plans to travel to the near-Earth asteroid Didymos, a binary system, and impact the smaller of the two bodies. NASA will assess the deflection result of the impact for potential future use on other potentially hazardous near-Earth objects. The project responds to near-Earth object guidance by the Office of Science and Technology Policy to better understand our impact mitigation posture, and to recommendations by the National Research Council Committee to conduct a test of a kinetic impactor. The DART mission is part of the Asteroid Impact and Deflection Assessment, which is an international collaboration with the European Space Agency.

Project Information

NASA Lead Center: Marshall Space Flight Center
International Partner: European Space Agency
Launch Location: TBD
Launch Vehicle: TBD
Mission Duration: 22 months
Requirement Derived from: NASA Authorization Act of 2008 and implementing guidance
Budget Portfolio: Science, Planetary Science

Project Summary

The DART project is working toward preliminary design review and project confirmation, but funding uncertainty and technology maturity of its propulsion system may change the project’s schedule. This uncertainty could trigger a reevaluation of life-cycle costs and overall schedule heading to preliminary design review and project confirmation. Further, DART’s planned electric propulsion thruster is facing development delays, particularly in its propulsion power systems. The project is looking at possible schedule delays should thruster issues persist.

DART was also intended to be one of two spacecraft to be sent to the Didymos binary asteroid system—along with a spacecraft produced and launched by the European Space Agency. The European spacecraft did not receive necessary funding for 2017 and may be canceled. The DART project is assessing the effect on collected science data of losing proximate observation and is in the early stages of considering various alternatives.

Cost and Schedule Status

Credit: GAO

The DART project entered the preliminary design and technology completion phase in June 2017 with the agency acknowledging that uncertain funding may affect the project’s schedule. This could trigger a re-evaluation of life-cycle costs and overall schedule heading to preliminary design review and project confirmation—which the project has delayed by 2 months and 1 month, respectively.

Credit: GAO

DART’s planned launch readiness date range is December 2020 – May 2021, with impact of the asteroid occurring in 2022. Project officials told us that if they receive less funding than planned, there is another launch opportunity 2 years later and they are currently studying the effects on the mission if it is delayed to this date. Officials also noted a delayed launch window would likely increase total costs in exchange for lower annual costs.

Technology

DART’s propulsion system includes technologies that remain immature and may delay the mission preliminary design review and potentially the project’s launch date. The DART project is working with NASA’s Evolutionary Xenon Thruster-Commercial (NEXT-C)—a project managed at Glenn Research Center under the Discovery Program—to provide in-space electric propulsion for the mission.

The DART mission will be the first time this technology will fly operationally and, if successful, will serve as qualification for future deep space missions. However, first-time production of this system—DART’s critical path and top risk—is proving challenging. The NEXT-C thruster’s power processing unit, which provides necessary voltages to the thruster, is the technical risk keeping the thruster from maturing.

The project has delayed the mission preliminary design review by 2 months in part to allow more time to mature the NEXT-C technology. In addition, the program is carrying a risk to its launch readiness date dependent upon the NEXT-C meeting delivery and design targets.

Developmental Partner

The DART project’s science collection may be less than originally planned due to the European Space Agency not funding DART’s sister project, the Asteroid Impact Monitor (AIM) project. DART was designed to work with AIM as part of the collaborative Asteroid Impact & Deflection Assessment.

Per the mission plan, as the DART spacecraft impacts the smaller of the Didymos binary asteroids, the AIM spacecraft would collect impact data along with Earth-based observatories. However, the AIM project did not receive necessary funding at the European Space Agency’s ministerial meeting in December 2016.

Losing AIM will reduce the amount of science data collected on the impact and the asteroids themselves. While the project believes that it can still meet its objectives of characterizing the results of the DART impact on the Didymos system, the project is performing planning and analysis leading up to preliminary design review to determine how effective the Earth-based observatories will be at determining the results of the impact event. As a result of the potential loss of science data, NASA is considering possible alternatives that could provide imagery and data related to the impact.

Project Office Comments

DART project officials provided technical comments on a draft of this assessment, which were incorporated as appropriate.