What is/was the smallest orbital launch system, by total mass?

What is (or was, if it's no longer in use) the system with lowest launch mass, capable of putting (any) payload in (or reaching) LEO? "How small" did we get with orbital flights?

(and yes, I realize economically that's a rather poor idea; still I'd like to know what was attempted.)

Juno 1 had a payload of 11 kg to LEO from a start mass of 29 t.

Diamant-A had a start weight of 18.4 t, payload 100 kg to LEO.

Black Arrow had a start weight of 18.1 t, payload 100 kg to LEO.

Vanguard, start weight of 10 t, payload 9 kg to LEO.

Lambda 4S had a start weight of 9.4 t, payload 26 kg to LEO.

Caleb was an air-launched missile theoretically capable of attaining orbit. Start weight of 1350 kg, payload 7 kg to LEO.

Project Pilot was an air-launched missile theoretically capable of attaining orbit. Start weight of 900 kg, payload 1 kg to LEO.

• I arrived at my answer through several iterations, starting with Juno and Diamant. I left them in to give an idea of the playing field. Commented Jul 11, 2016 at 12:43
• Thanks :) I wonder about thoughts of the pilot of the plane from which Calebs were launched, They had an uncanny tendency to explode on ignition, which would in this case probably mean "adjacent to the airplane".
– SF.
Commented Jul 11, 2016 at 13:02
• It doesn't seem fair to neglect the mass of the plane for the air-launched rockets. That's like neglecting the mass of stage 1 for a multi-stage rocket. Commented Jul 11, 2016 at 18:19
• Are they sorted by cost? Which was cheapest of the alternatives listed? Commented Jan 24, 2019 at 2:33
• They are in the order in which I found them. Theyr'e also mostly really old projects (from the 1950s-1960s). No idea about the cost. Commented Jan 24, 2019 at 7:04

The smallest launch system (by total mass) that has actually put something in orbit is the SS-520 (first successful orbital launch 3 February 2018).

• Start mass: 2,600 kg
• Payload to LEO: 9 kg

Current design and future designs:

• @uhoh: Yes, JAXA did. Commented Jan 21, 2019 at 4:30
– uhoh
Commented Jan 21, 2019 at 4:34
• I added a picture- hopefully it helps not hurts! The first thing I did when I saw this answer is look for some visuals! Looks like they plan to get even smaller too!!! Commented Jan 24, 2019 at 2:39
• Seems they have plans for a four stage nano- if that isn't cool I don't know what is. Commented Jan 24, 2019 at 2:52