Tag Archives: reusable

X Marks the Spot

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X Marks the Spot:  Falcon 9 Attempts Ocean Platform Landing

During our next flight, SpaceX will attempt the precision landing of a Falcon 9 first stage for the first time, on a custom-built ocean platform known as the autonomous spaceport drone ship. While SpaceX has already demonstrated two successful soft water landings, executing a precision landing on an unanchored ocean platform is significantly more challenging.

The odds of success are not great—perhaps 50% at best. However this test represents the first in a series of similar tests that will ultimately deliver a fully reusable Falcon 9 first stage.

Video of previous first stage reentry test with soft water landing

 

Returning anything from space is a challenge, but returning a Falcon 9 first stage for a precision landing presents a number of additional hurdles. At 14 stories tall and traveling upwards of 1300 m/s (nearly 1 mi/s), stabilizing the Falcon 9 first stage for reentry is like trying to balance a rubber broomstick on your hand in the middle of a wind storm.

To help stabilize the stage and to reduce its speed, SpaceX relights the engines for a series of three burns. The first burn—the boostback burn—adjusts the impact point of the vehicle and is followed by the supersonic retro propulsion burn that, along with the drag of the atmosphere, slows the vehicle’s speed from 1300 m/s to about 250 m/s. The final burn is the landing burn, during which the legs deploy and the vehicle’s speed is further reduced to around 2 m/s.

Landing legs deployed just before soft water landing in the Atlantic Ocean

To complicate matters further, the landing site is limited in size and not entirely stationary. The autonomous spaceport drone ship is 300 by 100 feet, with wings that extend its width to 170 feet. While that may sound huge at first, to a Falcon 9 first stage coming from space, it seems very small. The legspan of the Falcon 9 first stage is about 70 feet and while the ship is equipped with powerful thrusters to help it stay in place, it is not actually anchored, so finding the bullseye becomes particularly tricky. During previous attempts, we could only expect a landing accuracy of within 10km. For this attempt, we’re targeting a landing accuracy of within 10 meters.

A key upgrade to enable precision targeting of the Falcon 9 all the way to touchdown is the addition of four hypersonic grid fins placed in an X-wing configuration around the vehicle, stowed on ascent and deployed on reentry to control the stage’s lift vector. Each fin moves independently for roll, pitch and yaw, and combined with the engine gimbaling, will allow for precision landing – first on the autonomous spaceport drone ship, and eventually on land.

Similar steerable fins can also be seen in this test video:

The attempt to recover the first stage will begin after stage separation, once the Dragon spacecraft is safely on its way to orbit. The concept of landing a rocket on an ocean platform has been around for decades but it has never been attempted. Though the probability of success on this test is low, we expect to gather critical data to support future landing testing.

A fully and rapidly reusable rocket—which has never been done before—is the pivotal breakthrough needed to substantially reduce the cost of space access. While most rockets are designed to burn up on reentry, SpaceX is building rockets that not only withstand reentry, but also land safely on Earth to be refueled and fly again. Over the next year, SpaceX has at least a dozen launches planned with a number of additional testing opportunities. Given what we know today, we believe it is quite likely that with one of those flights we will not only be able to land a Falcon 9 first stage, but also re-fly.

http://www.spacex.com

SpaceX Soft Lands Falcon 9

SpaceX Soft Lands Falcon 9 Rocket First Stage

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Following last week’s successful launch of six ORBCOMM satellites, the Falcon 9 rocket’s first stage reentered Earth’s atmosphere and soft landed in the Atlantic Ocean. This test confirms that the Falcon 9 booster is able to consistently reenter from space at hypersonic velocity, restart main engines twice, deploy landing legs and touch down at near zero velocity.

 

After landing, the vehicle tipped sideways as planned to its final water safing state in a nearly horizontal position. The water impact caused loss of hull integrity, but we received all the necessary data to achieve a successful landing on a future flight. Going forward, we are taking steps to minimize the build up of ice and spots on the camera housing in order to gather improved video on future launches.

At this point, we are highly confident of being able to land successfully on a floating launch pad or back at the launch site and refly the rocket with no required refurbishment. However, our next couple launches are for very high velocity geostationary satellite missions, which don’t allow enough residual propellant for landing. In the longer term, missions like that will fly on Falcon Heavy, but until then Falcon 9 will need to fly in expendable mode.

We will attempt our next water landing on flight 13 of Falcon 9, but with a low probability of success. Flights 14 and 15 will attempt to land on a solid surface with an improved probability of success.

 

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SpaceX F9R Fin Test

F9R 1000m Fin Flight | Onboard Cam and Wide Shot

From the YouTube details section:

Jun 19, 2014
Video of Falcon 9 Reusable (F9R) during a 1000m test flight at our rocket development facility in McGregor, TX. This flight was our first test of a set of steerable fins that provide control of the rocket during the fly back portion of return. The fins deploy approximately a minute and 15 seconds into the flight, and return to their original position just prior to landing. The F9R testing program is the next step towards reusability following completion of the Grasshopper program last year. Early flights of F9R will take off with legs fixed in the down position, however we will soon transition to liftoff with legs stowed against the side of the rocket with leg extension just before landing. Future test flights of F9R at our New Mexico facility will include higher altitudes, allow us to prove unpowered guidance and to prove out landing cases that are more flight-like.

 

See also

SpaceX Falcon9

F9R First Flight Test

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SpaceX RTLS