Illustration
of a SpaceX Falcon-9 booster with its landing legs and hypersonic grid
fins deployed for a landing attempt. Image Credit: SpaceX
However, the opening minutes of Monday’s flight will be monitored with particular closeness, because SpaceX has another goal in mind as well: landing the first stage of their Falcon-9 v1.1 rocket on a floating platform in the Atlantic Ocean. The landing barge for the CRS-6 booster, named “Just Read The Instructions,” departed Jacksonville, Fla., at around 3:30 a.m. EDT this morning (April 11), headed for the rocket’s expected landing location 200-300 miles offshore.
“X” marks the spot? The Autonomous Spaceport Drone Ship (ASDS) in port. Photo Credit: SpaceX
SpaceX made their first landing attempt on the barge last January with the CRS-5 launch, and although the booster did not “soft-land” on the ASDS (or Autonomous Spaceport Drone Ship) it did hit the ASDS. That feat in and of itself was worthy of respect, especially considering that stabilizing the 150-foot-tall rocket stage in flight—traveling at a velocity of 2,900 mph at separation—has been likened to someone balancing a rubber broomstick on their hand in the middle of a fierce wind storm.
For CRS-5 SpaceX stressed a low-expectation of actually landing the booster successfully and in one piece; however, for CRS-6 Elon Musk said previously there is a “high probability of good droneship landing in non-stormy weather.”
That comment came after the company launched NASA’s DSCOVR mission last February, another launch which also had the added intention of another first-stage booster landing attempt on the ASDS. However, a rough storm at the landing location forced the company to call it off, instead trying to land the booster vertically in the water. The booster landed within 10 meters of the target, and vertical. In light of the storm, Musk said via his Twitter account that SpaceX was “planning a significant upgrade of the droneship for future missions to handle literally anything.”
Earlier this week the ASDS was brought offshore to test the upgrades made since the DSCOVR launch. We reached out to SpaceX for details about the upgrades but the company declined to comment.
The expectation is that once the Falcon-9 is truly reusable it will drive down the costs of access to space dramatically, while also reducing the turnaround time between flights.
ASDS landing profile for the SpaceX Falcon-9 booster. Image Credit: SpaceX
Azimuth thrusters can be rotated through a full 360 degrees to any horizontal angle (or “azimuth”), thereby rendering a rudder unnecessary and offering increased maneuverability over a fixed propeller and rudder system. Originally the thrusters aboard the ASDS were capable of producing 300 horsepower; however, several sources have noted that one of the upgrades made to the ASDS since the DSCOVR launch was replacement of those thrusters with 1000 horsepower versions. They form part of the Portable Dynamic Positioning System (PDPS), provided by Houston-based Thrustmaster of Texas, Inc., one of the world’s leading manufacturers of marine thruster systems.
Yet the return of a rocket first stage from the edge of space, and ensuring it remains stable atop an oceanic platform until its return to dry land, is entirely new territory. For the booster landing attempt the ASDS will be stationed between 186-250 miles (300-400 km) to the northeast of the Florida launch site.
SpaceX
CRS-5 booster hitting the ASDS in the first ever attempt to land a
rocket on a barge in January 2015. Photo: SpaceX / @ElonMusk via Twitter
In the meantime, SpaceX is already beginning to build the actual landing site for their rockets, at the old Launch Complex-13 on Cape Canaveral Air Force Station, under a recently signed five-year lease agreement with the U.S. Air Force. Although instead of being called “Launch Complex-13,” it is now designated as “Landing Complex-1.” A primary concrete landing pad will be developed, surrounded by four smaller contingency landing pads for use in case a landing rocket is not quite on the bull’s eye.
The company is also planning similar operations at their west coast launch site at Vandenberg AFB, Calif. Another ASDS named “Of Course I Still Love You” will serve as the company’s Vandenberg barge while SpaceX continues on the reusability development path to landing their rockets back on solid ground.