NASA delays launch of James Webb Space Telescope to 2020
The highly anticipated launch of NASA’s James Webb Space Telescope (JWST) has been delayed to May 2020 due to the need for extensive testing and integration of its parts, which the agency says it now recognizes will take longer than previously anticipated.
This is not the first launch postponement for the observatory planned to be the Hubble Space Telescope’s successor. JWST has been plagued with cost overruns and delays for years.
In 2002 NASA, in partnership with the European Space Agency and Canadian Space Agency, signed an $824.8 million contract with the aerospace company TRW for construction of an infrared space telescope, with launch planned for 2010. TRW was subsequently acquired by Northrop Grumman.
By 2005, the estimated cost of the project had risen to approximately $4.5 billion. Its technology passed the mission critical design review in 2010, with launch now scheduled for some time between 2015 and 2018.
Citing poor management and JWST being billions of dollars over budget, the U.S. House of Representative’s Appropriations Committee on Commerce, Justice, and Science in 2011 threatened to cancel the project but reversed its position on condition the cost be capped at $8 billion.
Last year, 2017, problems with the telescope’s assembly delayed its launch from 2018 to 2019.
Acting NASA Administrator Robert Lightfoot, Associate Administrator of NASA’s Science Mission Directorate Thomas Zurbuchen, and Directorate Deputy Associate Administrator Dennis Andrucyk announced the latest delay at a press conference on Tuesday, March 27, 2018.
“Following data from an independent assessment, NASA has determined that the Webb launch date milestone will be delayed from its baseline by more than six months, and its development cost estimate might exceed the $8 billion development limit,” Lightfoot said. “If we breach the $8 billion cost that was laid out in the Congressional appropriations, the project will need to be reauthorized by Congress.”
JWST’s Standing Review Board recently determined that although the hardware on both the telescope and spacecraft meet the project’s requirements, more time is needed to successfully integrate their components. A separate Independent Review Board established by NASA will review the project’s technical and management issues and present a report of its findings and recommendations to Congress this summer.
The spacecraft includes a sun shield that will protect JWST‘s science instruments and a spacecraft bus that will carry its flight avionics, solar panels, and power system.
Within the next year, the spacecraft will be combined with the 21.3-foot (6.5-meter) telescope and science payload, both of which have successfully undergone testing at NASA’s Johnson Space Center in Houston, Texas, last year.
For launch, the sun shield will be folded origami-style into the fairing of an Ariane 5 rocket that will carry the observatory to space.
Testing of the sun shield has taken longer than initially initially expected. While mission scientists planned to test deploy it for two weeks, then fold and stow it for a month, the actual deployment took a month, and the folding and stowing took two months.
Because the cables that hold the sun shield had too much slack, the shield’s membranes developed seven small tears during the test period, two of which were four inches wide.
JWST will be placed in the Earth-Sun lagrangian point one million miles from Earth, meaning there will be no way to repair any part of it should a problem develop after launch. Any tears in the sun shield would render the telescope useless, as its instruments must be kept cold to protect them from the Sun, Earth, and Moon’s heat, light, and infrared radiation.
Also behind schedule is JWST‘s propulsion system.
“An incorrect solvent was run through the propulsion system; as a result, we wound up having to replace valves in that system, and a catalyst bed heater was accidentally over-stressed and needed to be replaced,” Andrucyk said at the press conference. “Those [issues] are avoidable errors, but in developing very complex systems, those things do happen.”
Environmental testing of the spacecraft, which involves subjecting it to the conditions it will face during launch and in orbit, will be conducted over the next few months. These will be followed by integration of the entire observatory and tests to assure all components function properly together.
The infrared telescope’s primary mirror is composed of 18 hexagonal segments and was assembled between November 2015 and February 2016. It will have seven times the light-gathering power of Hubble.
Once launched, JWST will observe the universe’s earliest stars and galaxies in infrared light. Scientists also plan to use it to study the atmospheres of exoplanets as they transit in front of their parent stars. The telescope is expected to operate for a period of five to ten years.
“Webb is the highest priority for the agency’s Science Mission Directorate, and the largest international space science project in U.S. history,” Lightfoot said. “All the observatory’s flight hardware is now complete; however, the issues brought to light with the spacecraft element are prompting us to take the necessary steps to refocus our efforts on the completion of this ambitious and complex observatory.”
“Considering the investment NASA and our international partners have made, we want to proceed systematically through these last tests, with the additional time necessary, to be ready for a May 2020 launch,” Zurbuchen said.
Video courtesy of Northrop Grumman
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.