ULA with their Atlas V seems to be the leading launch service provider for secondary payloads. This FISO presentation is convincing anyway. And good for them since miniaturization of satellites certainly seems to be happening for real. How do other launch providers, commercial and foreign, compare on this market? And how do launch costs per kilogram differ from that of a heavy primary payload?
Arianespace offers secondary payload space on both Ariane 5 and Vega. Their earliest 'microsatellite' launch was using the ASAP structure on an Ariane 40 on January 22, 1990.
- The Ariane 5 can launch 2 large satellites using the SYLDA (SYstème de Lancement Double Ariane) fairing.
- Also for the Ariane 5, the Ariane Structure for Auxiliary Payloads (ASAP) is a ring at the base of the payload stack which contains 4 or 8 positions for small satellites. These can be up to 600 mm x 600 mm x 710 mm and a weight of up to 120 kg each.
This is an ASAP with components of the LDREX-2 experiment.
- For VEGA, the VEga Secondary Payload Adapter (VESPA) can hold 2 payloads of up to 400 kg each/600 kg total underneath the main payload.
- for VEGA, development of an adapter for smaller payloads was underway in 2013.
- VEGA flight VV01 carried a "plate dispenser" for 7 cubesats and a microsatellite.
As for cost, a launch on an Ariane 4 using ASAP is reported to cost around \$1.2 M (1990-2000 timeframe).
So, comparing with ULA:
- Arianespace's 1990 first launch predates the ULA effort (and ULA itself) significantly.
- the range of payloads is similar.
- I haven't found a cost for ULA secondary payloads.