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Space Japan

Japan Launches the World's Smallest Satellite-Carrying Rocket (nasaspaceflight.com) 64

Japan has launched the world's smallest satellite-carrying rocket. Long-time Slashdot reader hey! writes: Last week Japan Aerospace Exploration Agency (JAXA) successfully placed a three-kilogram cubesat into an 180 x 1,500 kilometer orbit at 31 degrees inclination to the equator. The payload was launched on a modified sounding rocket, called the SS-520-5. The assembled rocket weighed a mere 2600 kilograms [2.87 tons] on the launchpad, making the SS-520-5 the smallest vehicle ever to put an object into orbit.

Note that the difference in the SS-520's modest orbital capacity of four kilograms and its ability to launch 140 kilograms to 1000 kilometers on a suborbital flight. That shows how much more difficult it is to put an object into orbit than it is to merely send it into space.

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Japan Launches the World's Smallest Satellite-Carrying Rocket

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  • Kim Jong Un would like to buy some

    • by hey! ( 33014 )

      If NK has 4 kg nuclear warhead, we've got bigger problems than their getting their hands on a Japanese sounding rocket.

      • Yeah, buy 140 kg is a suborbital lob, and that's not nearly as insanely small. The Davy Crockett has a mass of around 40 kg https://en.wikipedia.org/wiki/Davy_Crockett_(nuclear_device) [wikipedia.org]. That involved pretty heavy miniaturization, but a warhead with slightly higher yield and slightly less miniaturization and a size of around 140 kg isn't implausible. Detonating a nuke the size of Davy Crockett on New York still does some pretty serious damage http://nuclearsecrecy.com/nukemap/?&kt=0.04&lat=40.72422 [nuclearsecrecy.com]
        • by hey! ( 33014 )

          Kind of moot given that the Hwasong 15 can deliver 1000 kg to most of the continental US.

        • Considering that a 300 kt warhead weighs about the same number of kilograms today, I'd say that 140 kg is more than enough.
      • You don't need to put a warhead in to orbit.

        I imagine you could land a payload anywhere on earth if you send it up 1000km, like this rocket can do with 140kg payload.

        • by Kjella ( 173770 )

          I imagine you could land a payload anywhere on earth if you send it up 1000km, like this rocket can do with 140kg payload.

          No, not even close as rockets have no air to glide in or wings to glide with. When NK sent their Hwasong-15 missile about 4500km straight up the experts said it could hit a target about 13000km away on a ballistic trajectory. So for a 140kg payload I'd estimate a 3000km range. And this is a considerably more powerful rocket than what NK got, it couldn't put anything in orbit and their test launch probably had essentially no payload. North Korea could almost certainly nuke Japan if they wanted, that's only 1

      • by gl4ss ( 559668 )

        140 kilos of tnt anywhere in the world in a 2.8 ton rocket. ..he sure as fuck would like some of those. would be more useful than nukes, harder to detect launch/re-entry and so forth.

    • Kim Jong Un would like to buy some

      Well, he can't buy some. They use the Über gig model.

      If he wants to ride in a rocket, he will have to use the app, just like everyone else.

      He doesn't have any problems with the rocket taxi unions. He shot the union leaders out of circus canons spiked with C-4, or killed them in other cruel, unusual or bizarre methods.

  • by CaptainDork ( 3678879 ) on Sunday February 04, 2018 @06:41PM (#56067799)

    ... miniaturization.

  • The Japanese satellite contained a 27-room luxury capsule hotel [wikipedia.org] -- with a spectacular view of Japan, every 92 minutes.

  • by Michael Woodhams ( 112247 ) on Sunday February 04, 2018 @06:56PM (#56067887) Journal

    Scott Manley is a great youtube commentator on space stuff. Last year he made a video on the smallest orbital rockets. [youtube.com]

    Since then, Electron and now SS-520 have orbited satellites, so it is a little out of date. He starts with the Electron and talks about the previous SS-520 launch is covered at 4m40s. Numerous other rockets get a mention.

  • Why not to design the satellite as some sort of long cilindre and to use a militar converted jet to carry it "near" the atmosphere limit and just to send it the remaining distance as a missile? You can take a lot of decisions, even to return home if the conditions are not optimal, and the sending device is 100% reusable without almost no effort.
    • by amiga3D ( 567632 ) on Sunday February 04, 2018 @07:13PM (#56067969)

      They've used that for anti-satellite missile tests that were successful before. I'm sure that one or other of the "black ops" outfits has some such capability to quickly put spy sats in orbit.

    • by Geoffrey.landis ( 926948 ) on Sunday February 04, 2018 @07:15PM (#56067981) Homepage

      Why not to design the satellite as some sort of long cilindre and to use a militar converted jet to carry it "near" the atmosphere limit

      You've just re-invented the Pegasus [wikipedia.org]. Not to mention Virgin Orbital. And Stratolaunch.

      You do need something that carries a heavier payload than a fighter, though--

      and just to send it the remaining distance as a missile?

      It's not the distance-- it's the velocity. Orbital velocity is about Mach 25; you only get a tiny fraction of that from a jet. But, it does help, some, mostly because getting above much of the atmosphere does help.

      • In addition, if you can mount wings on the first stage (even fairly short ones), you might get away with initial T/W of less than one and with a higher expansion nozzle for optimized vacuum operation.
    • by hey! ( 33014 ) on Sunday February 04, 2018 @07:28PM (#56068025) Homepage Journal

      Probably because it wouldn't make that much difference. Getting to space is the easy part; the lion's share of the energy needed for low earth orbit is accelerating your payload to 7km/s or 15,000 mph.

      Using a mothership makes a lot of sense if you're going for a suborbital jaunt, as with SpaceShipOne, which at 3600 kg is comparable in size to this rocket. But the energy savings you'd get is such a tiny fraction of what's needed for orbit it's not worth the engineering and logistical complications.

      • For small missiles a carrier plane does make a significant difference, small rockets suffer from atmospheric drag losses much more than big ones. That is why you can't scale an orbital rocket down to estes model rocket size to launch post stamps to orbit.
    • From here: [nasaspaceflight.com]

      Japan has not announced plans for any further orbital launches with the SS-520 – and last year’s launch was originally intended to have been a one-off, but project is an experiment which JAXA and the Japanese space industry hope will lead to an operational nanosatellite launch system in the future.

      So the future "operational nanosatellite launch system" might use an air launch, but for a one-off test it was not worth developing this capability.

      Air launch is something that is done by Pegasus and is being developed by a few other operators. It makes more sense at the small payload end of the market than the big end, so it might be a good approach.

    • Because 140kg is a nice size for a small nuclear weapon. And 1000km is a nice range for hitting Korea and....
      • You are right, there must be a different motivator in the sub-orbital range.

      • by hey! ( 33014 ) on Sunday February 04, 2018 @09:42PM (#56068473) Homepage Journal

        JAXA has vehicles capable of putting over sixteen metric tons in orbit.

        But if they wanted to nuke North Korea, the easiest way would be to adapt a missile fired from one of their attack submarines or guided missile destroyers.

        Really, JAXA has done something cool here, and the only context people can think of it in is nukes?

        • Really, JAXA has done something cool here, and the only context people can think of it in is nukes?

          Nukes are the elephant in the room when it comes to orbital class and ballistic missiles. The reason people freaked out about Sputnik wasn't because people were saying "wow, look at the new options for communications!" No, it was because a missile that can launch a comsat can also carry a warhead and put it anywhere on the globe under an hour. It's dual use technology so we HAVE to consider the military applications whether we want to or not. If Japan can build one of these then (theoretically) so can N

    • That's a mediocre improvement over launching it from the ground. Getting it high enough is not the issue, getting it fast enough is the problem, and starting at 400 mph hardly makes a difference.

            The advantage to launching off an airplane is that you can fly the airplane to the spot you need any day of the year, which is the value of Pegasus and the other similar schemes. It hardly helps the mass ratio/launch throw weight at all.

  • I hear they have a lot of little rockets over there, so I would expect them to hold the record...

  • While I can understand some approximation error, the math should still stand unharmed!

    • by Muros ( 1167213 )

      While I can understand some approximation error, the math should still stand unharmed!

      True. But it is also 2.559 tons, and 2.866 tons, and 2.388 tons, and probably some other values as well. Welcome to the joys of the imperial measurement system.

      • While I can understand some approximation error, the math should still stand unharmed!

        True. But it is also 2.559 tons, and 2.866 tons, and 2.388 tons, and probably some other values as well. Welcome to the joys of the imperial measurement system.

        Also true.
        What I expect as a dumb person, is precision. We (I'm European) have just 1 ton(ne) = 1,000 Kg.
        On the other side there are short tons and long tons and specifying which one is intended is perceived as a measure of precision.

        This is the same craze that lead to that poor space probe known as "Mars Climate Orbiter [wikipedia.org]" to get lost.

  • Suborbital just means 2000 km/h or so. Orbital means 27,000 km/h - that is more than 10 times as fast. When Bezoz launches suborbital he goes vertical, a missile is launched mostly upwards, and when an orbital rocket/spaceshuttle goes up it tips almost horizontal within a minute of launch - most of the velocity is going eastward (or southward from polar orbits), not upwards. Watch the speed and height numbers in any SpaceX launch.
  • "The assembled rocket weighed a mere 2600 kilograms [2.87 tons]" You meant 2600kg = 2.6 ton, clearly?
    • by sl3xd ( 111641 )

      Don't confuse a ton and a tonne.

      2600 kg is:
      * 2.87 short/US tons.
      * 2.56 long/imperial tons
      * 2.6 tonnes

  • Although to be honest, the Vanguard rocket was heavier, and the satellite smaller.

God made the integers; all else is the work of Man. -- Kronecker

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