SpaceX’s DragonFly test vehicle has arrived at its test facility in McGregor, Texas. DragonFly will be attached to a large crane, ahead of a series of test firings of its SuperDraco thrusters to set the stage towards the eventual goal of propulsive landings. The first test is set to take place in the next few weeks to kick start around two years of incremental testing.
How To Train Your Dragon 2:
SpaceX’s aspiration towards fully reusable rocket systems is an ongoing process currently focused on the recovery and reuse of the first stage of its Falcon 9.
Although plans to reuse the second stage are currently on the back burner, several attempts to land the core stage on a floating platform in the Atlantic Ocean have resulted in incremental refinements and improvements – although SpaceX is yet to nail a landing.
Testing towards that goal began with the Grasshopper program, based at the McGregor test center. Now DragonFly will attempt to follow in its footsteps, as the spacecraft sets up for a series of tests aimed at the ultimate goal of landing under its own propulsive power.
Arriving at its new home at the McGregor base – on the back of a flatbed truck – this month, the DragonFly enjoyed a brief meeting with the Grasshopper test vehicle for a photo opportunity.
Initially, DragonFly won’t be reaching the heights of the Grasshopper or the since-deceased F-9R Dev-1 test rocket.
That is in part due to the initial test sequence that will be incremental in its approach, but mainly due to the guidance provided in the current Federal Aviation Administration (FAA) permit.
“SpaceX may operate the Dragonfly vehicle to an altitude that does not exceed 80 feet AGL, in accordance with its application.”
Although the permit also calls for numerous additional constraints, such as a 3,000-foot safety clear zone, the test will be monitored close up by numerous engineering cameras, likely – per SpaceX’s tradition – to result in a specular video of the testing to be released to the public.
What such a video will show will be the DragonFly “dancing” under the power of her SuperDraco thrusters while tethered to a large crane.
That crane has also been spotted at McGregor by locals, separate from the cranes associated with the regular testing of stages at the test site.
Such a technique of tethering a rocket-powered vehicle to a crane has been seen many times before, not least the initial testing of NASA’s Morpheus lander that was utilized to test green propellant propulsion systems and autonomous landing and hazard detection technology.
The Morpheus project ran from its conception in the summer of 2010, through to its final test flight in December of 2014.
It was first tested at the Johnson Space Center (JSC) via a number of powered tests while attached via tethers to a crane.
Its successor followed a similar path before successfully completing the test objectives at the SLF.
The DragonFly will follow a similar path to Morpheus. Sporting four steel landing legs and weighing in at 14000 lbs unfueled, the initial tests will shake out the SuperDraco thrusters and prepare the vehicle for an ambitious test regime.
DragonFly testing will be housed at a 40-foot square pad near the SuperDraco facility.
Pending permit requirements, four kinds of test flights are envisioned after the crane-based testing has been completed.
These include the “Propulsive assist landing” test – which will see DragonFly dropped from helicopter (an Erickson E‐model or equivalent) aided by three parachutes. This will be followed by the “Fully propulsive landing” test, concluding with a five-second firing of the SuperDracos for a smooth landing.
Next would be the “Propulsive assist hop” test. This would call for the DragonFly to be self-launched via a 12.5 second firing of the SuperDracos, removing the helicopter from testing. It would include parachute deployment assist, but with only two chutes, prior to a propulsive landing.
Finally, the test series calls for a “Fully propulsive hop” test, not unlike the Grasshopper tests. During this test, the DragonFly will rise to approximately 7,000 ft AGL, firing its engines for approximately 12.5 seconds to achieve this height.
The engines would then throttle down in order to descend, with the engines firing for an additional approximate 12. 5 seconds, allowing the DragonFly to make a powered landing on the launch pad.
The SuperDracos – burning a combination of monomethylhydrazine (MMH) and nitrogen tetroxide (NTO) – that will be at the heart of the testing have already enjoyed a successful test as a group, firing together during the successful Pad Abort test at SpaceX’s SLC-40 Pad at Cape Canaveral. That Pad Abort vehicle has now been revamped into the DragonFly.
The liquid SuperDraco engines, built into the side walls of the Dragon spacecraft, have a major role during an abort, producing up to 120,000 pounds of axial thrust to drive the Dragon and crew safely away from a failing launch vehicle.
They can reach full thrust within approximately 100 milliseconds of the ignition command.
The utilization of the same engines for a propulsive landing capability ensures they will always find a role during Dragon 2’s future role.
Dragon 2 – which is set to launch to the ISS under NASA’s Commercial Crew contract – will initially land under parachutes, prior to progressing towards propulsive landing attempts. Parachutes will remain installed on the spacecraft, in order to provide redundancy.
The initial DragonFly testing is expected to take place in a matter of weeks, following on from the full-duration static fire test for the first upgraded “Full Thrust” Falcon 9 first stage.
The stage, which is set to provide the initial push uphill for the ORBCOMM-2 mission – is back on the test stand at McGregor and is currently undergoing engine re-installation in preparation for its final test ahead of shipping to Cape Canaveral for SpaceX’s Return To Flight mission that is likely to take place in early December – although officially the target remains in late November.
(Images: Via SpaceX and L2 – including photos from the L2 McGregor Section and renders from L2 artist Nathan Koga – The full hi-res gallery of Nathan’s (SpaceX Dragon to MCT, SLS, Commercial Crew and more) L2 images can be *found here*)
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