Early Monday morning, SpaceX achieved a successful launch and landing of its Falcon main stage, which sent a Dragon capsule loaded with supplies to the International Space Station. Unlike most previous attempts, the Falcon was able to return to Florida rather than dropping onto a barge in the Atlantic. The successful landing adds another item to the company's collection of lightly used boosters, some of which are intended to ultimately make return trips to space.

The Dragon capsule is expected to reach the ISS within two days. It contains a typical assortment of supplies and experiments in its pressurized portion. But it also carries a bit of hardware externally: an international docking adaptor, or IDA. The IDA is built to standards that different nations can adopt, allowing their hardware to interact with the system. According to NASA, "the adapter is built so spacecraft systems can automatically perform all the steps of rendezvous and dock with the station without input from the astronauts."

This is the second IDA sent to the Station, the first having exploded in one of SpaceX's rare failed launches.

The company has had a bit more trouble nailing the landings, as would be expected. But last night's went off without a hitch, possibly aided by the fact that the Falcon booster returned to land rather than a gently rocking barge. This is now the fifth booster the company has returned from space. While it intends to preserve the first, the others are slated to be tested and returned to service if they're found to be up for the job. We're still waiting for the first re-use at this point, however.