SpaceX: All four landing legs now mounted on Falcon 9 rocket

All four landing legs now mounted on SpaceX Falcon 9 rocket being processed inside hanger at Cape Canaveral, FL for Mar 16 launch. 

Credit: SpaceX/Elon Musk 

The historic blast off of the first SpaceX Falcon 9 rocket equipped with 'landing legs' and also carrying the Dragon cargo vessel is bound for the Space Station.

The launch is now slated for March 16, following a short and "successful" hot fire check test of the first stage engines on Saturday, March 8.

The brief two second ignition of all nine upgraded Merlin 1D engines powering the first stage of SpaceX's next generation, commercial Falcon 9 rocket at the end of a simulated countdown, is a key test.

The rocket engine milestone test is required to clear the way for next Sunday's planned night time lift off at 4:41 a.m. EDT from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.

SpaceX owner and entrepreneur, Ellon Musk, is shown here next to a model of the Dragon spacecraft.

 "Falcon 9 and Dragon conducted a successful static fire test in advance of next week's CRS-3 launch to station!" SpaceX announced today.

The primary goal of the unmanned SpaceX CRS-3 mission is to deliver over 5000 pounds of science experiments, gear and supplies loaded inside Dragon to the six person crew living and working aboard the International Space Station (ISS) flying in low Earth orbit under NASA's Commercial Resupply Services (CRS) contract.

"In this final major preflight test, Falcon 9's 9 first-stage engines were ignited for 2 seconds while the vehicle was held down to the pad," said SpaceX.

The static hot firing is a full up assessment of the rocket, engines, propellant loading and countdown procedures leading to a launch. The engines typically fire for a barely a few seconds.

SpaceX engineers will evaluate the engine firing to ensure all systems are ready for launch.

SpaceX's New Merlin 1D Rocket Engine Cleared for Private Launches

Two of SpaceX's Merlin 1D engines sit on a test stand at the company's rocket-development facility in McGregor, Texas.

Credit: SpaceX

SpaceX's next-generation rocket engine is ready to fly and will likely power a commercial space launch for the first time this summer, company officials announced Wednesday (March 20).

The Merlin 1D engine was judged flight-ready after firing for a total of nearly 33 minutes over the course of 28 different tests at SpaceX's rocket-development facility in McGregor, Texas. The new engine will soon be incorporated into the company's Falcon 9 rocket, officials said.

"The Merlin 1D successfully performed every test throughout this extremely rigorous qualification program," SpaceX CEO and chief designer Elon Musk said in a statement. "With flight qualification now complete, we look forward to flying the first Merlin 1D engines on Falcon 9’s Flight 6 this year."

The Falcon 9 has flown five times to date, most recently on March 1, when it blasted the robotic Dragon capsule toward the International Space Station on California-based SpaceX's second contracted supply run for NASA. According to the company's launch manifest, flight number six will launch a Canadian communications satellite, likely in mid-June.

Company officials say the Merlin 1D will provide a big boost for the Falcon 9, which until now has been powered by Merlin 1C engines in its first stage (nine of them, hence the name).

"The Merlin 1D has a vacuum thrust-to-weight ratio exceeding 150, the best of any liquid rocket engine in history," SpaceX officials wrote in a press release Wednesday.

"This enhanced design makes the Merlin 1D the most efficient booster engine ever built, while still maintaining the structural and thermal safety margins needed to carry astronauts."

SpaceX indeed plans to launch astronauts using the Merlin 1D. The company is working on a manned version of its Falcon 9/Dragon transportation system, in the hopes of scoring a NASA contract to ferry astronauts to and from the space station.