SpaceX to attempt Falcon 9 first stage landing again with SpX-6 flight
CAPE CANAVERAL, Fla — Space Exploration Technologies (SpaceX ) has prepared both the cargo version of the firm’s Dragon spacecraft and the Falcon 9 v1.1 launch vehicle that it will carry aloft, and are being readied for a planned April 13 liftoff. If everything goes according to plan, the booster will thunder off of the launch pad at Cape Canaveral Air Force Station’s Space Launch Complex 40 at 4:33 p.m. EDT (20:33 GMT). On board the cargo vessel will be some 4,300 lbs (1,950 kg) worth of cargo, experiments, and crew supplies bound for the International Space Station. When the rocket’s first stage has completed its job, it will be directed to carry out the second landing attempt on a vessel out in the Atlantic Ocean off the Coast of Jacksonville, Florida.
As with every launch for one of the Falcon 9 boosters, the last milestone on the path to orbit was the static fire test that the aerospace company conducted on April 11, 2015, at around 5:00 p.m. EDT (21:00 GMT). With this last essential test completed, the company was freed up to carry out tomorrow’s launch – and landing attempt of the Falcon 9’s first stage.
“Dragon will stay up there for 35 days, the longest that we’ve ever been on station,” Hans Koenigsmann, SpaceX’s Vice President of Mission Assurance. “In terms of tomorrow’s landing attempt, conditions are much improved compared to last time. There would be an epic landing party! (laughs)”
Once this mission is complete, with the Dragon spacecraft bobbing in the Pacific Ocean off the Coast of California, SpaceX will have six more flights to complete under the $1.6 billion contract that SpaceX has with NASA. Under this agreement, the Hawthorne, California-based firm is contractually obligated to fly 12 missions, with some 20,000 kg worth of cargo to the space station.
For tomorrow’s mission, SpaceX will have what is called an “instantaneous” launch window. In short, launch controllers have just one second to get the rocket and its precious cargo off of the launch pad and into the sky. After the booster takes to the skies, the aerospace company will be relying on the technology that it has incorporated into the Falcon 9 which has seen the rocket launch 16 times in six years. Outside of a single “engine out” anomaly in October 2012, all of the Falcon 9 flights have been 100 percent successful – and even that engine anomaly gave a first (unscheduled) demonstration of the Falcon 9’s “engine out” capability in flight.
SpaceX entered into an agreement with NASA to fly to the ISS with the Commercial Orbital Transportation Services (COTS ) contract in 2006 along with the now-defunct Rocketplane Kistler (RpK ). With the successful completion of the COTS 2 mission, which was flown in May of 2012, this mission, in essence, saw the COTS 2 and COTS 3 demonstration missions merged into a single flight – Dragon C2+, which SpaceX carried out almost flawlessly.
“The issues we encountered with the Falcon 9’s helium bottles, could best be described as us showing an over-abundance of caution,” Koeniggsman said. “In terms of this launch, there was no significant impact.”
Tomorrow’s flight – the CRS-6 mission – actually got its start months ago with the delivery of both of the Falcon 9’s stages being delivered to the Rocket Development Facility at the company’s McGregor, Texas, test facility. Once these components were tested, the two stages were then transported individually via truck to SLC-40.
The booster’s two stages were then integrated with the Dragon spacecraft that will be used for this flight. Dragon is sent directly from Hawthorne to Cape Canaveral. Once at the Cape, Dragon is loaded with the cargo for this flight.
“The late cargo is on hand and we are preparing to hand that over to SpaceX within the next hour (as of 5 p.m. EDT),” said Dan Hartman, NASA’s deputy program manager for the ISS. “The one year ‘crew’ Scott and Mikhail are in full swing and they, along with the rest of the crew, are looking forward to SpX-6’s arrival.”
This cargo is carefully selected by NASA, along with SpaceX, so as to best suit the requirements of the crew on the station and to meet the capabilities provided by the Dragon.
These preparations culminate some two weeks prior to liftoff with a Formal Stage Operations Readiness Review, which involves key members involved with the Space Station Program. These include NASA, the Russian Federal Space Agency (Roscosmos ), the European Space Agency (ESA ), the Japan Aerospace Exploration Agency (JAXA ), and the Canadian Space Agency (CSA ), among others.
As was noted, the turbulent Florida weather remains the chief concern of conditions prohibiting a launch, with a 40 percent chance of unfavorable conditions.
“Typically in Florida, in April, the weather conditions are rather dry. However, what we have seen and expect to see in the coming days – is unusual,” said the 45th Space Wing’s Dave Kraft. “The blowoff from the anvils (clouds) are currently looking like that will occur around T-0.”
Twenty-six hours prior to flight, the Dragon spacecraft will be powered up so that NASA’s powered cargo can be loaded onto the transport vessel.
Two hours later, the Falcon 9 booster itself will be hoisted into the vertical position in preparation for the flight. Ground personnel will then leave the pad so that the Falcon 9 can be fueled in preparation for flight.
Just four hours before the countdown clock strikes zero, fueling of the RP-1 (a highly-refined version of kerosene) propellant will be loaded into the booster.
A plume of white vapor should be visible coming off of the Falcon 9 after the propellant has been loaded with fuel. This is excess gaseous oxygen being vented from the rocket’s tanks. This process requires oxygen to be added continuously prior to the countdown procedure.
Terminal count for tomorrow’s flight will begin 10 minutes before the rocket takes flight. At this point, all of the systems are controlled via computer autonomously. Outside of the public’s imagination, there is no “big red button” with the word “launch” on it. The actual launch is a carefully coordinated effort.
Mission Control, located in Hawthorne, will be polled as well as the launch team in Cape Canaveral (located just outside of Gate 1, near the U.S. Air Force Space & Missile Museum) to provide the final clearance for launch at just two and a half minutes before launch. Thirty seconds later, the U.S. Air Force Range Control Officer provides the final go ahead for launch with confirmation that the Eastern Range is clear for liftoff.
Just before the Falcon 9 and Dragon take to the skies – Niagara is unleashed. No, not the three waterfalls that mark the border between Canada and the United States – the sound suppression, deluge system that prevents the tremendous sound of liftoff from destroying the rocket.
Just a few seconds prior to launch, the nine Merlin 1D engines, arranged in the Octaweb configuration, in the rocket’s first stage will ignite. The booster is held firmly in place until the flight computers confirm that everything is functioning as advertised. If everything checks out, when the clock strikes T-0, the Falcon, utilizing 1.3 million pounds-force (5.78 MN) of thrust, thunders off of the launch pad and on its way into the black.
Upon reaching orbit, Dragon will make its way to the ISS, utilizing UHF communication through the spacecraft’s COTS Ultra-high-frequency Communication Unit or “CUCU”.
Dragon will be guided by controllers on the ground to within approximately 820 feet (250 meters) of the station using close-range guidance systems that are composed of Lidar and thermal imagers.
Although stated otherwise elsewhere – Dragon does not dock with the space station. Rather, members of the Expedition 43 crew will capture the spacecraft using the station’s Canadarm2 Robotic Manipulator System and then berth it to the Earth-facing side of the station’s Harmony module.
Once there, the crew will ensure that the seal between the station and Dragon cargo vessel is secure – before they open the hatch and begin offloading supplies. Once they have removed all of the supplies and experiments, they will begin uploading finished experiments and trash. After about four weeks on the station, the crew will then detach Dragon and allow the craft to conduct re-entry.
Currently, the SpX-6 Dragon is slated to remain on the station for a little more than a month, with its missions scheduled to draw to a close with the capsule’s departure on May 20.
Unlike all other vehicles that currently journey to the International Space Station (excluding the crewed version of Soyuz), Dragon is the only vehicle that can carry out re-entry – with a significant amount of experiments from the orbiting lab.
Weather is the primary concern with tomorrow’s launch, a fact that Hartman noted in his initial comments at a press conference held at NASA’s Kennedy Space Center in Florida on April 10.
“If for some reason, likely weather, we can’t launch tomorrow, we have a backup date of the 14. If the launch slips past that, we’ll have to take a second look at what is going on at the range as well as with the science teams (in terms of Dragon’s cargo),” Hartman said.
Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology, Space.com, The Mars Society and Universe Today.