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

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.

Comments

Scott Manley video on small rockets

[Michael Woodhams]

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

Since then, Electron and now SS-520 have orbited satellites, so it is a little out of date.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.

Re:Why not to use a jet for this?

[Geoffrey.landis]

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. 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.

Re:Why not to use a jet for this?

[hey!]

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.