Activities around the first U.S.-flagged commercial cargo supply missions to the International Space Station (ISS) are on the rise. On April 16, SpaceX (News - Alert) will undergo its final NASA flight review for the April 30 launch of its COTS 2/3 demonstration mission. 

Meanwhile, Orbital is releasing the first stage of its new Antares rocket on a brand new pad out of Wallops Island, VA as a part of what the company calls "pathfinder" operations.

The April 16 Flight Readiness Review (FRR), conducted in Houston at the Johnson Space Center, will include senior NASA managers, representatives of the space station partners (Russians, Europeans, and Japanese) and SpaceX officials. At this point, unless there's some last minute surprise – highly unlikely at this point – the review should wrap up in the early afternoon.

A briefing will immediately follow the review, for the media and participants including NASA associate administrator for William Gerstenmaier, Human Exploration and Operations; Michael Suffredini, ISS program manager; and Elon Musk, SpaceX CEO/lead designer.

SpaceX is scheduled to hit an "instantaneous" launch window time on April 30. In the event of a technical hiccup or a weather delay, the company will recycle the launch in three days time, and thereafter until they can hit a window.  Upon launch from Cape Canaveral Air Force Base in Florida, the Falcon 9 rocket will put a cargo-carrying Dragon space capsule and service module into orbit for a nice, conservative checkout of all systems. 

If all goes well, Dragon will do a fly-under of the station at 2.5 kilometers to validate the operation of sensors and flight systems needed for a safe rendezvous, and demonstrate the capability to abort the rendezvous. 

From there, assuming no issues, Dragon will come closely enough to the space station to allow the crew to grapple the vehicle with the station's robotic arm. It will then be berthed – pulled in and connected to a docking port using the station's arm, connections made and the capsule will open. At the end of the mission, the crew will reverse the process, detaching Dragon so the capsule can return to earth for a Pacific Ocean splashdown.

Orbital, the other, less-heralded vendor of NASA's COTS/CRS cargo flight program, is in the process of walking through the rollout and erection of its Antares rocket at MARS launch Pad 0A at Wallops Island. The company has released pictures of the Antares first stage being moved from the Horizontal Integration Facility (HIF) to the launch pad onboard its Transporter/Erector/Launcher (TEL). 

A first-stage static test first of Antares is scheduled for May, followed by a full-up test flight of Antares in June, but those dates are dependent upon encountering no bugs at the brand new launch pad or with the rocket. The new pad was necessarily built from scratch at Wallops Island to support liquid fueling, a process that took considerably longer than originally estimated.

Orbital expects to conduct its NASA COTS demonstration mission in the third quarter of this year, assuming Murphy's Law is on holiday for the next few months.