Ariane 5 launch
An Ariane 5 lifts off Jan. 25 from Kourou, French Guiana. The launch would suffer an anomaly that resulted in placing its two satellites into the wrong orbits. Credit: Arianespace

WASHINGTON — NASA, whose James Webb Space Telescope is scheduled to launch on an Ariane 5 next year, will be included in the European investigation into an anomaly suffered by the rocket on its most recent launch.

Arianespace announced Jan. 26 the formation of an “independent enquiry commission,” to be chaired by the European Space Agency’s inspector general, that will study the anomaly during the Jan. 25 launch that placed two communications satellites into the wrong orbits. Both satellites will be able to achieve their desired geostationary orbits, but later than planned and with some potential reduction in spacecraft lifetime.

Neither Arianespace nor ESA have released details about the investigation since that announcement. Reports in French media claim a programming error in the vehicle’s computers may have caused the “trajectory deviation” announced by Arianespace.

The anomaly came after a streak of 82 successful launches in a row for the Ariane 5, whose last launch failure was more than 15 years ago. It also created nervousness for scientists and engineers involved with JWST, as the Ariane 5 is scheduled to launch the $8 billion space telescope in a launch window between March and June 2019.

In a Jan. 31 interview at the National Academies here during an event marking the 60th anniversary of the launch of the first U.S. satellite, Thomas Zurbuchen, NASA associate administrator for science, said that the agency would participate in the Ariane 5 inquiry. He added that ESA has been very open so far about the investigation.

NASA and ESA agreed more than a decade ago to launch JWST on an Ariane 5, with ESA providing a launch as part of its contribution to the mission in exchange for a share of observing time on the telescope. While that launch issue seemed settled long ago, some members of Congress sought to revisit the decision even before the anomaly.

At a Dec. 6 hearing of the House space subcommittee on NASA space telescope projects, Rep. Brian Babin (R-Texas), chairman of the subcommittee, raised the issue. “Why was the decision made to launch the $8 billion JWST on the European Ariane 5 rocket, instead of a reliable U.S. launch vehicle?” he asked.

Zurbuchen, who noted the decision to use the Ariane 5 was made long before he joined the agency in 2016, said cost and international collaboration were factors in the decision to use the rocket for JWST. “We don’t believe there’s a conflict of leadership for the United States” by using the Ariane 5 to launch JWST, he told Babin.

A spokesperson for the House Science Committee said Jan. 29 that the committee didn’t have any additional comment on the use of the Ariane 5 in light of the recent anomaly.

Neither Arianespace nor ESA have given a timetable for the investigation, although Arianespace said in its Jan. 26 statement that upcoming launch campaigns would proceed as scheduled. The next Ariane 5 launch, of two communications satellites, is currently scheduled for mid-March.

Jan Woerner, director general of ESA, said in a Jan. 26 tweet that he believed the rocket would return to service and carry out its remaining missions successfully. The rocket has fewer than two dozen launches left through the early 2020s before it is replaced by the Ariane 6. “Confident this will reinforce our industrial teams for a successful continuation of Ariane 5 and its remaining missions,” Woerner said.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...