The Japanese Aerospace Exploration Agency has set a record for the smallest-ever rocket to launch a satellite into orbit, using a SS-520 sounding rocket modified to include a third stage carrying a 36cm TRICOM-1R cubesat as its payload.
Per Engadget, JAXA's original SS-520 launch with the same objective ended in failure in January 2017 when a technical malfunction prevented its second stage from activating. Investigators later found vibrations caused a short circuit and took the rocket's transmitters offline.
According to a machine-translated version of JAXA's press release, the launch was successful and the TRICOM-1R is functioning as expected:
Unit 5 of the SS-520 flew as planned, succeeded in separating the TRICOM-1R (Trichom One Ear) micro satellite in orbit for about 7 minutes 30 seconds after the experiment. The TRICOM-1R's status is normal.
The Japan Times reported that the rocket was "about the size of a utility pole, measuring 10 meters [33 feet] in length and 50 centimeters [20 inches] in diameter," and that it was built using "components found in home electronics and smartphones." However, it's not exactly tiny, per Spaceflight Now:
According to JAXA documents, the SS-520-5 weighed nearly 2.9 tons (2.6 metric tons) at launch, with nearly 2.2 tons (2 metric tons) of that weight made up of pre-packed solid propellants. The SS-520-5's first stage, fitted with spin-stabilizing fins, was loaded with nearly 3,500 pounds (1,587 kilograms) of HTPB solid fuel.
A gaseous nitrogen thruster package was designed to keep the SS-520-5 rocket pointed correctly during a one-and-a-half minute coast phase between the launcher's first and second stage burns.
The second and third stages consumed 716 pounds (325 kilograms) and 172 pounds (78 kilograms) of propellant, respectively.
Its payload, the TRICOM-1R, weighs 140kg and carries radios and Earth-imaging gear.
As the Verge noted, JAXA's launch is part of an overall trend in spaceflight towards smaller vehicles which are able to deliver miniaturized payloads.
New Zealand's Rocket Lab launched an Electron rocket in January, deploying four small satellites including a disco ball visible from the Earth's surface that astronomers are pretty angry about. Smaller rockets are cheaper to build and could ultimately reduce barriers to entry for small spaceflight companies.