If Elon Musk ultimately fulfills his dream of making mankind a multi-planetary species, historians will look back on the evening of December 21, 2015 as a significant milestone.  SpaceX successfully returned its Falcon 9 launch vehicle back into operations with the successful launch of 11 ORBCOMM satellites into low Earth orbit and returned the first stage back to a successful landing at Cape Canaveral, Florida.  It is the first time a rocket stage has been flown and recovered in commercial operations and opens to door for drastically lowering the cost of putting satellites and people into space.

Billed as a "secondary test objective" and an "experimental landing" by SpaceX, the Hawthorne, California company clearly felt confident enough in recovery to stream the landing live on YouTube with a backdrop of hundreds of employees watching launch and landing operations in real time.

The two stage Falcon 9 rocket lifted off from Space Launch Complex 40 around 8:29 pm ET at Cape Canaveral, Florida, one of three pieces of real estate SpaceX leases in the area.  The launch marked SpaceX's return-to-flight after the loss of the CRS-7 supply flight to the International Space Station on June 28, 2015 and featured an upgraded version of Falcon 9.

At about 2 minutes and 24 seconds into launch, the first and second stages of the Falcon 9 separated, with the single-engine second stage lighting a handful of seconds later and moving into low Earth orbit, starting to deploy the first of the eleven ORBCOMM satellites 15 minutes into flight with the last satellite deployed at about 20 minutes into flight.  

All eleven ORBCOMM OG2 satellites, part of a constellation of 17 machine to machine (M2M) communication satellites, successfully "checked in" on orbit after deployment, marking the end of a long saga for ORBCOMM to get them into orbit.

While the second stage continued on its way into orbit, three of the nine engines in the first stage conducted a boostback -- turn around -- burn at 4 minutes into flight, with a re-entry burn at 8 minutes into flight, followed by the first stage landing at "Landing Zone 1" at the Cape a mere 10 minutes after launch.  Residents of Florida's Space Coast heard a sonic boom as the first stage came for landing while the successful touchdown was cheered by SpaceX employees as lustily as a Times Square New Year's ball drop.

SpaceX twice previously tried to land the Falcon 9 first stage on a floating barge, with the second attempt coming tantalizing close to success before the stage tipped over and crashed on the deck.  This third attempt, the first on land and requiring Federal Aviation Administration (FAA) permission, may have been spurred by Blue Origin's suborbital flight with first stage landing last month.

Today's successful landing is only the first step in reusability.  SpaceX engineers will go over the first stage in fine detail along with all of the flight data.  It is not clear how fast or how soon SpaceX will refly the first stage or others.  The company has a stacked up launch manifest, with the SES-9 communications satellite scheduled for launch in mid-January from Florida, a NASA/NOAA ocean monitoring satellite out of Vandenberg Air Force Base in California mid-January, and resumption of supply missions to the space station with a flight in February.  SpaceX will presumably try to fly back one or more first stages back from those missions, gaining additional experience and reusable hardware.

The "Holy Grail" for lowering launch costs is to reuse the first stage in the same manner as an airplane, rather than discarding the expensive hardware on each flight. Established "Old Space" companies have long been skeptical and resistant to the idea of reusability, doubting the economics and feasibility.   SpaceX's next tasks will be to demonstrate the ability to successfully refly a first stage and to do so at a price significantly lower than the list price of a new launch vehicle. The company plans to land first stages both for the Falcon 9 medium launch vehicle and the Falcon Heavy, the latter designed to put large communications and defense satellites into orbit.