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posted by martyb on Thursday December 07 2017, @08:49AM   Printer-friendly
from the hurricane-blew-schedule-out-of-the-water dept.

The Government Accountability Office (GAO) is warning of possible further delays to the launch of the James Webb Space Telescope (JWST):

A government watchdog is warning that the launch of the James Webb Space Telescope (JWST), the long-awaited successor to the Hubble that's been beset by schedule snafus and cost overruns, might face further delays. NASA announced in September it had pushed back the launch date of the JWST from late 2018 to some time in the spring of 2019 due to testing delays partly blamed on Hurricane Harvey's impact on Texas' Gulf Coast in August.

On Wednesday, lawmakers on the House Science, Space and Technology Committee were told it could take even longer to launch the world's most powerful telescope. "More delays are possible given the risks associated with the work ahead and the level of schedule reserves that are now (below) what's recommended," said Cristina Chaplain, director of Acquisition and Sourcing Management for the Government Accountability Office.

[...] Thomas Zurbuchen, NASA's associate administrator for science missions, told lawmakers he expects the space agency will be able to meet the spring 2019 schedule. "I believe it's achievable," he said.

Previously: James Webb Space Telescope Vibration Testing Completed
Launch of James Webb Space Telescope Delayed to Spring 2019

Related: Maiden Flight of the Space Launch System Delayed to 2019
NASA Unlikely to Have Enough Plutonium-238 for Missions by the Mid-2020s
WFIRST Space Observatory Could be Scaled Back Due to Costs


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  • (Score: 5, Interesting) by takyon on Thursday December 07 2017, @11:28AM (4 children)

    by takyon (881) Subscriber Badge <{takyon} {at} {soylentnews.org}> on Thursday December 07 2017, @11:28AM (#606764) Journal

    It has been argued that space telescopes gobble up funding [nature.com] that could be used by productive ground-based astronomy. But the capabilities you can get in return are just too overwhelming.

    https://jwst-docs.stsci.edu/display/JSP/JWST+GTO+Observation+Specifications#JWSTGTOObservationSpecifications-ObservationsofSolarSystemObjects [stsci.edu]

    Many of the most interesting astronomical targets (exoplanets, protoplanetary/debris disks, brown dwarfs, KBOs) require infrared observations which will never be as good from the ground, even with the help of adaptive optics. In fact, its location at L2 forgoes even more observation-interfering heat than would be possible at LEO (like Hubble).

    JWST is past the point of cancellation. Now it has to get up there and work properly. If the launch vehicle explodes or the telescope fails to work, it will be the biggest blow to astronomy in a long time. This thing has a credible chance of finding evidence of life on exoplanets, will provide the best ever views of many objects in and out of the solar system, etc. We will be lucky to get ATLAST [wikipedia.org]/HDST [wikipedia.org]/LUVOIR [wikipedia.org] in the 2030s, especially if JWST fails. Apparently, future flagships would have to be serviceable due to a law Congress passed in 2010. Hopefully, someone will come up with a relatively cheap way to refuel JWST once it becomes unable to do any more station-keeping.

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  • (Score: 2) by Grishnakh on Thursday December 07 2017, @03:53PM (3 children)

    by Grishnakh (2831) on Thursday December 07 2017, @03:53PM (#606837)

    If we had a permanent human presence on the Moon, this might not be such an issue: we could build ground telescopes on the Moon cheaper than space telescopes, and they'd be a lot easier to service. The main disadvantage is you wouldn't have as much flexibility in which direction you point them. Of course, this would only work with a significant human presence there already: manufacturing facilities, people on hand to build them, qualified people who can take a rover out and service a telescope if there's a problem, etc. With a space telescope, if it doesn't work perfectly right away, you have to spend tons of money on a manned mission to send someone up there to fix it.

    • (Score: 2) by takyon on Thursday December 07 2017, @04:09PM (2 children)

      by takyon (881) Subscriber Badge <{takyon} {at} {soylentnews.org}> on Thursday December 07 2017, @04:09PM (#606842) Journal

      With a space telescope, if it doesn't work perfectly right away, you have to spend tons of money on a manned mission to send someone up there to fix it.

      I don't see any reason why it can't be done with robots. The not-designed-to-be-serviced JWST faces a very simple challenge to its maximum lifespan: it will run out of propellant for station-keeping. If it can't be refueled or maintained by an external thruster, then that would be very. UNFORTUNATE.

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      • (Score: 0) by Anonymous Coward on Thursday December 07 2017, @08:29PM (1 child)

        by Anonymous Coward on Thursday December 07 2017, @08:29PM (#606978)

        It's orbit would degrade, from a LaGrange point? And then it would plummet back to earth? Your point is taken, takyon, but not for station-keeping, for aiming the darn thing, and keeping its solar shield pointed, you know, toward the sun.

        • (Score: 2) by takyon on Thursday December 07 2017, @09:05PM

          by takyon (881) Subscriber Badge <{takyon} {at} {soylentnews.org}> on Thursday December 07 2017, @09:05PM (#606988) Journal

          https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Orbit [wikipedia.org]

          The JWST will be located near the second Lagrange point (L2) of the Earth-Sun system, which is 1,500,000 kilometers (930,000 mi) from Earth, directly opposite to the Sun. Normally an object circling the Sun farther out than Earth would take longer than one year to complete its orbit, but near the L2 point the combined gravitational pull of the Earth and the Sun allow a spacecraft to orbit the Sun in the same time it takes the Earth. The telescope will circle about the L2 point in a halo orbit, which will be inclined with respect to the ecliptic, have a radius of approximately 800,000 kilometers (500,000 mi), and take about half a year to complete. Since L2 is just an equilibrium point with no gravitational pull, a halo orbit is not an orbit in the usual sense: the spacecraft is actually in orbit around the Sun, and the halo orbit can be thought of as controlled drifting to remain in the vicinity of the L2 point. This requires some station-keeping: around 2–4 m/s per year from the total budget of 150 m/s. Two sets of thrusters constitute the observatory's propulsion system.

          L2 is "metastable", not stable like L4 and L5.

          https://jwst.nasa.gov/realworld_parrish.html [nasa.gov]

          JWST, which orbits around Lagrange Point Two, will carry enough fuel for orbit maintenance. If it should fall out of orbit it could end up being pulled into the orbit of the Sun, or even less likely return to Earth.

          NASA has a disposal requirement at the end of JWST's useful life that ensures the telescope won't be a hazard to human life, or other spacecraft. At the end of its mission we will point it in a direction in which it won't be able to return to Earth and we'll use the remaining fuel to send it that way.

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