• NASA satellite's 'shocking' space junk near-miss was even closer than t

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    from https://www.space.com/nasa-timed-satellite-russian-space-junk-near-miss-february-2024

    NASA satellite's 'shocking' space junk near-miss was even closer than
    thought
    News
    By Mike Wall published 5 hours ago
    "It was very shocking personally, and also for all of us at NASA."

    Comments (0)
    illustration of a spacecraft orbiting earth
    Artist’s impression of NASA's TIMED spacecraft in orbit, scanning Earth. (Image credit: Johns Hopkins APL/Steve Gribben)
    Humanity dodged an orbital bullet recently by an even slimmer margin
    than we thought.

    In the wee hours of Feb. 28, the dead Russian spy satellite Cosmos 2221
    and NASA's TIMED craft, which has been studying Earth's atmosphere since
    2001, made an uncomfortably close pass in orbit, zooming within a mere
    65 feet (20 meters) of each other.

    That was the initial estimate, anyway. Further study has shown that the
    shave was actually even closer, according to NASA Deputy Administrator
    Pam Melroy.

    "We recently learned through analysis that the pass ended up being less
    than 10 meters [33 feet] apart — within the hard-body parameters of both satellites," Melroy said April 9 during a presentation at the 39th Space Symposium in Colorado Springs.

    "It was very shocking personally, and also for all of us at NASA," she
    said, adding that the encounter "really scared us all."

    Related: 7 wild ideas to clean up space junk

    She explained the concern: "Had the two satellites collided, we would
    have seen significant debris generation — tiny shards traveling tens of thousands of miles an hour, waiting to puncture a hole in another
    spacecraft, potentially putting human lives at risk."

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    This is not merely a theoretical issue. In August 2021, for example, the Chinese military satellite Yunhai 1-02 got whacked by a piece of space
    junk — apparently a bit of debris from the Zenit-2 rocket that launched Russia's Tselina-2 spy satellite in 1996.

    While such hits remain rare, near misses such as the one TIMED survived
    are becoming more and more common, for Earth orbit is getting more and
    more crowded.

    There are currently about 11,500 satellites circling our planet at the
    moment, 9,000 of which are operational, according to the European Space
    Agency (ESA). More than half of these functional craft, by the way, are
    part of SpaceX's Starlink broadband network; the ever-growing
    megaconstellation currently consists of nearly 5,800 satellites.

    But that's just part of the picture. There are about 36,500 pieces of
    space junk at least 4 inches (10 centimeters) wide in Earth orbit, ESA estimates, and more than 130 million shards at least 1 millimeter across.

    As Melroy noted, even such tiny slivers of debris can do damage to
    satellites and the International Space Station (ISS), given the
    velocities involved. At the ISS' orbit, about 250 miles (400 kilometers)
    up, objects move at around 17,500 mph (28,160 kph) — far faster than any bullet.

    RELATED STORIES:
    — 6 objects that could cause space debris apocalypse

    — The Kessler Syndrome and the space junk problem

    — Space collision: Chinese satellite got whacked by hunk of Russian
    rocket in March

    NASA has worked over the years to help mitigate the space-junk problem,
    Melroy added. As an example, she cited the agency's work two decades ago
    to help implement "common-sense practices," such as the passivation of
    rocket upper stages in orbit — a process that involves, among other
    actions, venting their remaining fuel to reduce their explosive potential.

    But the agency wants to do more, Melroy said. And that increased push
    includes an integrated "space sustainability strategy," the first part
    of which NASA released the day of Melroy's talk.

    "Developed under the leadership of a crossagency advisory board, the
    space sustainability strategy focuses on advancements NASA can make
    toward measuring and assessing space sustainability in Earth orbit,
    identifying cost-effective ways to meet sustainability targets,
    incentivizing the adoption of sustainable practices through technology
    and policy development, and increasing efforts to share and receive
    information with the rest of the global space community," agency
    officials said in an April 9 statement.

    NASA's sustainability strategy will eventually encompass four domains:
    Earth, Earth orbit, cislunar space (the region near and around the moon)
    and deep space. The 35-page first volume focuses on sustainability in
    Earth orbit, agency officials said.

    You can learn more about the sustainability strategy, and read the first volume, via NASA here.

    Join our Space Forums to keep talking space on the latest missions,
    night sky and more! And if you have a news tip, correction or comment,
    let us know at: community@space.com.

    Mike Wall
    Mike Wall
    Senior Space Writer
    Michael Wall is a Senior Space Writer with Space.com and joined the team
    in 2010. He primarily covers exoplanets, spaceflight and military space,
    but has been known to dabble in the space art beat. His book about the
    search for alien life, "Out There," was published on Nov. 13, 2018.
    Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the
    University of Sydney, Australia, a bachelor's degree from the University
    of Arizona, and a graduate certificate in science writing from the
    University of California, Santa Cruz. To find out what his latest
    project is, you can follow Michael on Twitter.

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