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Japan Successfully Launches Solid Fuel Rocket (oann.com)
randomErr writes: Japan successfully launched a solid fuel rocket named Epsilon-2. The 26-meter-long rocket launched from the Uchinoura Space Center at about 8 p.m. local time. Japan Aerospace Exploration Agency (JAXA) said this is the latest in Tokyo's effort to stay competitive in an industry that has robust growth potential and strong security implications. Also, this is to curb costs for rocket launches. The Epsilon-2 three-stage rocket [is part of a new generation of solid propellant rockets that aim] to put communication and weather satellites in space.
https://www.nasaspaceflight.co...
This is news for nerds. Any "nerd" who doesn't think rocketry is awesome should probably turn in their badge on the way out.
Usually you have to fill liquid fuelled ones up just before you launch them. This means if anyone is observing you, they know in advance that you're going to launch.
This can be a disadvantage for certain applic@.m,mk
no carrier
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Why would Japan want such a thing after having avowed a no nuclear policy after being subjected to the only nuclear attack in history?
As far as I can tell, japan has considered to not be a nuclear power almost in name only for quite a while. They have an active space programme, a strong nuclear industry with reprocessing, first world tech and science, active heavy industry, leading supercomputing capability and so on.
Yes, they are avowedly anti nuclear on paper, but when push comes to shove, it's entirely obvious they could have a nuke up in the air with pretty short notice.
Now, while they had a good space program, what they lacked was an excellent delivery vehicle. Liquid fueled rockets are superior in many regards, but as a delivery mechanism for nukes they are not. Solid fuelled rockets are stable, robust, transportable and fuelled and ready to go with no notice 24/7 for years at a time.
Now, there's not been much hurry, but North Korea has been acting more threatening recently, and China is beginning to get a bit miliraristic round that area about ownership of some islands.
I don't think there's a huge desire to become a nuclear power but this sends a message that they could and very quickly if they desired. At this point if Japan felt it had to start it's own manhattan program, well, it would probably be scant months before they reach the stage where they could drop a warhead on more or less anywhere in the world at short notice and from hard to predict locations.
SJW n. One who posts facts.
US ICBMs are solid fuel rockets. This is so they can be launched quickly before an attack by an adversary can take them out.
That said the primary design goal for this particular rocket is low cost. One of these particular rockets costs only $38 million. Many launch systems aimed at putting about 1000 kg into orbit are solid fuel because it's relatively cheap to build and operate a solid-propellant rocket and you don't need to squeeze every last bit of specific impulse out of the rocket to launch a modest payload.
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Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
Solid rocket motors have tradeoffs. In some circumstances, they make sense.
They are long-term storage-stable. Build it, stick it in a silo somewhere, and leave it be for a few years, it will still launch just fine. Hypergolic liquid-fueled rockets can't be kept ready-to-launch for more than a few days*, and cryogenic liquid-fueled rockets can't be kept ready-to-launch for more than a few hours. This makes them particularly preferable for military uses, everything from little anti-tank rockets to ICBMs. This also reduces the number of ground crew needed - you don't need to worry about fueling, just electricals and signals.
They have extremely high levels of thrust, due to the extremely high energy density. The Shuttle's SRBs were each twice as powerful as the largest liquid-fueled rockets. This makes them very popular as boosters.
They have a lot of impulse per unit volume. What most rockets care about is impulse per unit mass (aka specific impulse), but some cases care about volume. If you're launching from an aircraft, like Stratolaunch or Pegasus, this matters. If you have constrained volume because you're in a fixed-size fairing, this matters. If you're launching from a submarine, this matters.
It's also often a matter of economies of scale. Countries with military missile programs (which have many reasons to go solid-fueled) often use them for other things as well, either to subsidize their military-industrial complex or to take advantage of existing scale to make civilian rocketry cheaper, depending on how cynical you are. The US, masters of solid-fueled ICBMs, used a pair of massive SRBs on the Space Shuttle, and will use them again on SLS, if that ever flies. The ESA's Ariane 5 uses SRBs based on a French SLBM. Japan may not field ICBMs, but they too have a reason - the first stage of this rocket is almost identical to the booster of their H-II rocket.
The higher stages are solid-fueled presumably to maintain that low-ground-crew capability, and the minor reduction in drag can't hurt either.