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ISS NASA Space Science

Cygnus ISS Launch Delayed Due To Sun's Coronal Mass Ejection 30

Posted by Soulskill
from the sol-is-begging-for-attention-again dept.
ClockEndGooner writes "A giant coronal mass ejection from the Sun yesterday has resulted in a higher than normal level of radioactivity, and in turn, forced Orbital Sciences to postpone their first mission launch of the Cygnus space truck to the International Space Station. Citing concerns of the effect increased levels of space radiation may have on the Antares launcher and Cygnus avionics, the NASA and Orbital launch team is now evaluating if conditions will improve for a launch on Thursday, which would have Cygnus arriving at the ISS on Sunday morning." In other ISS news, the Orlando Sentinel is reporting that NASA has gotten approval from the White House to extend the ISS's mission for another four years, pushing the end date back to 2024. An official announcement is expected later this week.
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Cygnus ISS Launch Delayed Due To Sun's Coronal Mass Ejection

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  • Re:CME frequency (Score:2, Informative)

    by Anonymous Coward on Wednesday January 08, 2014 @03:29PM (#45900509)

    If you're living under a significant magnetosphere, only the regions near the magnetic poles tend to notice anything from flares. Canada has an established expectation that they will get power fluctuations with every aurora. Even in those vulnerable regions, consumer grade electronics are safe from the direct effects, and if you have a surge protector, safe from the indirect effects.
    Modern consumer grade electronics are built to much tighter specifications and energy tolerances than most historic scientific and military equipment (modern military electronics are EM hardened versions of two year old consumer gear).

    However, for those without as much magnetosphere and without the miles of (relatively) dense gasses, every stray blast of solar matter is a cause for concern. Usually concern for the electronics and sensors, sometimes concern for the lives of those aboard.

  • Radioactivity? (Score:5, Informative)

    by dtmos (447842) * on Wednesday January 08, 2014 @04:27PM (#45901035)

    Um, no. "Radiation" was the word for which you were looking. "Radioactivity" refers to the particles which are emitted from nuclei as a result of nuclear instability.

    There was a significant solar flare at 1832z (1:32 p.m. EST) on 7 January, that bathed the Earth with electromagnetic radiation (X-rays, UV, radio, etc.). This was an X1.2-class flare [spaceweather.com], meaning that its flux would have peaked at 1.2E(-4) watts/square meter at the Earth's surface, had our atmosphere not protected those of us on the ground from the worst of its effects. The effects of the flare itself (largely attenuation of HF radio signals over the Western Hemisphere during and shortly after the event) are over and done with.

    Since this flare was caused by a particular sun spot group that remains active and unstable, Orbital Sciences was concerned about a repeat performance when the Antares' avionics were in the upper atmosphere, and therefore not protected from a second, possibly even more intense, flare that the sun spot may produce.

    Concurrent with this flare was a coronal mass ejection (CME), which consists largely of protons blasted out of the sun's atmosphere (the corona). Since these particles are protons, not massless photons, they travel slower than the speed of light, and it takes them a while to get here; they are expected to arrive sometime early on 9 January UTC. However, predictions of CME particle velocity are difficult and prone to error; CMEs can arrive early.

    Since the CME could be arriving while the Antares was in operation (the flight was scheduled for liftoff at 1832z on 8 January), and the performance of the rocket's avionics could not be guaranteed in that environment, when this risk was combined with the risk of another X-class flare I think they just decided that a scrub was the wiser choice.

  • by Cochonou (576531) on Wednesday January 08, 2014 @04:44PM (#45901203) Homepage
    Although TFS states that:
    Citing concerns of the effect increased levels of space radiation may have on the Antares launcher and Cygnus avionics
    It is actually written in TFA that:
    The Cygnus spacecraft would not be affected by the solar event.

    Having been involved in the design of some of the avionics onboard Cygnus, I can attest that a S2/S3 class solar event [noaa.gov] such as this one is well within the specifications of the spacecraft..

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