back to article NASA installs a new and improved algorithm to better track near-Earth asteroids

NASA has upgraded its near-Earth asteroid monitoring algorithm to model hazardous space rocks more accurately after nearly two decades, it announced on Tuesday. The new system, dubbed Sentry-II, is more powerful than its predecessor, Sentry. Astronomers working at the space agency's Center for Near Earth Object Studies can now …

  1. Neil Barnes Silver badge

    "With Sentry-II, we don’t have to do that anymore"

    That sounds like an excellent addition to the software... but I hope there will be a long period of observation to check that what is now automatically calculated instead of tedious manual calculation does actually predict the results observed. One wonders about second and third order effects, possibly currently unknown...

    "Is that chunk of rock going to hit us?"

    "Computer says no."

    "Ah, she'll be fine!"

    1. Pascal Monett Silver badge

      Re: "With Sentry-II, we don’t have to do that anymore"

      Technically I agree with you, however this is NASA we're talking about, not Borkzilla.

      I'm sure that, if they put the software in production, they did the checking beforehand and are confident that it works as intended.

    2. Version 1.0 Silver badge

      Re: "With Sentry-II, we don’t have to do that anymore"

      NASA wrote the original program and it's worked well, now they are updating it and documenting the update so I trust them 100% - the description is a good example of how science works and NASA engineers do a very good job.

      But think what we'd be looking at if Microsoft and other modern app creators had written the original prediction "app" - it would have been "updated" with new features added but no description of the methods ... and we'd all be getting a new update soon that would require buying a new CPU to "remain safe."

      1. Anonymous Coward
        Anonymous Coward

        Re: "With Sentry-II, we don’t have to do that anymore"

        I'm not so sure I trust NASA as inherently... Even the astronauts wanted things double checked.

        John Glenn in 1962 wanted the numbers checked when sent to orbit the Earth three times as it was the first time that the orbit numbers were crunched by "new" computers. So he specifically wanted Katherine Johnson to do it.

        As someone else has commented, how does one test/verify such a system...

    3. fredblogggs Bronze badge

      Re: "With Sentry-II, we don’t have to do that anymore"

      What does it matter, though? Knowledge of an impending impact is not actionable given current technology, nor any technology that is in development. The entire project puts the cart before the horse: develop and test a reliable means of deflecting or rearranging an impactor first, then figure out when and where it will be needed. If you're really worried, you can do them in parallel, but the technical problems of avoiding or mitigating an impact are several orders of magnitude more challenging than doing math, so there'd be little use for this until such a system was completed and in final testing. In other words, if you need to solve multiple problems to get something useful to happen, start solving the hardest problems first.

      An optimising compiler would elide this entire body of software as the results it produces are never consumed.

  2. Anonymous Coward
    Anonymous Coward

    software used to protect humanity

    does it?

    1. John Robson Silver badge

      Re: software used to protect humanity

      More importantly - how will we debug it :p

      1. Doctor Syntax Silver badge

        Re: software used to protect humanity

        If it's wrong debugging is the least of your problems.

    2. m4r35n357

      Re: software used to protect humanity

      s/protect humanity/detect impending doom/g

    3. fredblogggs Bronze badge

      Re: software used to protect humanity

      It protects us from being able to spend our money on things that are potentially useful to us. Does that count? I suppose it also protects a handful of people from having to do useful work to earn a living; perhaps that's what was meant.

      There is no science being done here, and no useful application of existing knowledge. Lacking any means to deflect or rearrange an impactor, all that will happen if an impact is predicted is a handful of government elites will be told about it. Their response will be an orgiastic spending frenzy -- you can't take it with you -- and perhaps hiding themselves in some protected location if the impact is to be minor. For the rest of us, pffffft!

  3. tiggity Silver badge

    low level

    "low-level code in Fortran and Python"

    Did the definition of "low level" code change recently? Never thought Fortran low level (& I have coded in it)

  4. Nigel Sedgwick

    Relevance to Solar Wind

    Does anyone know any useful level of detail in the relevance of solar wind to predicting asteroid orbits? Also the ranking of these different sorts of modest effect?

    Solar wind is not mentioned in the technical paper, though obviously the reported approach is designed to deal with a multiplicity of detailed orbital effects.

    The concern I have with solar wind is that I suspect (I'm not an astrophysicist) it is more variable and perhaps more significant. Also prediction of variations (eg from observing solar flares) is subject to a lack of information of those on the far side of the sun.

    Ultimately, I would have thought that there is an intrinsic lack of detailed knowledge that would make orbital predictions (especially of medium-sized asteroids, big enough to be dangerous to Earth and also small enough to have larger orbital variations) markedly unreliable beyond a modest timeframe.

    Keep safe and best regards

    1. Cuddles Silver badge

      Re: Relevance to Solar Wind

      "The concern I have with solar wind is that I suspect (I'm not an astrophysicist) it is more variable and perhaps more significant."

      It is more variably, but pretty much entirely insignificant. At 1 AU, which is the relevant distance from the Sun for things that might hit Earth, pressure from solar wind is around 1 nPa. So for a body with a Sun-facing area of 1 km^2, that's a 1e-3 N force, and a consequent acceleration of ~ 1e-14 m/s^2. In comparison, the Yarkovsky effect on the same body will cause a force of 0.25 N and acceleration around 1e-12 m/s^2. Far from being more significant, solar wind is on the order of a thousand times less significant. Yes, it's more variable, but any spikes are very short-term events. A CME might increase the solar wind by an order of magnitude or two, but that still only means it might be about the same strength as the Yarkovsky effect for a day or two, compared to being that strong all day, every day, for millions of years.

      As for lacking information, we're really not. Things like CMEs happen on long enough timescales, and across large enough volumes of space, that we don't have any problem knowing they've happened even when the bulk of an event's activity occurs on the far side of the Sun from us.

      "Ultimately, I would have thought that there is an intrinsic lack of detailed knowledge that would make orbital predictions (especially of medium-sized asteroids, big enough to be dangerous to Earth and also small enough to have larger orbital variations) markedly unreliable beyond a modest timeframe."

      Absolutely. Orbital mechanics is a tricky business. The question comes down to what you consider to be a modest timeframe. Taking one of the examples from the article, asteroid 1950 DA has issues with the Yarkovsky effect because it creates some uncertainty in exactly where it will be 800 years from now. It would be utterly irrelevant to an object predicted to hit us within any living person's lifetime, but astronomers tend to consider things happening on a scale of centuries or millennia to be disturbingly fast. These kinds of tiny effects aren't at all relevant to the average person, it's just that scientists generally like to know things as accurately as possible even if it's something that will only affect distant descendents.

  5. Fruit and Nutcase Silver badge
    Thumb Up

    No mention of

    AI/ML. Phew

  6. Craig 2

    Sentry-II: more powerful than its predecessor, Sentry.

    Say what you want about NASA wasting money but at least they didn't* hire a huge panel of consultants to determine a new, trendy public-friendly name** for the software. Sentry II: Job done.

    *Please God, tell me they didn't hire consultants and this was what they came up with...

    **Suggestions on a postcard to the usual address...

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