(Source: SpaceX)
Automated safeguards detected an issue in the craft's actuators and reportedly shut it down safely, averting potential trouble

SpaceX had to scrub its first launch of 2015 at roughly 5:09 am this morning, which would have used the company's Falcon 9 booster to send its reusable Dragon resupply vessel to the International Space Station (ISS) with a shipment of supplies.  It now is hoping for a Friday do-over for the critical launch, which was set for the most ambitious test yet of SpaceX's cost-saving booster reuse plan.

The mission is a pivotal one for SpaceX as it marks the company's first attempt at the delicate maneuver of landing a core piece of the Falcon 9 (v1.1) booster rocket on a barge in the ocean near the launch site after detaching.  The Dragon capsule has always been reusable (recovered via ocean splashdowns), but the res  of the craft was traditionally lost during missions, including the pricey first stage booster section.

The plan is to use a bit more fuel in order to save the main first-stage engines, and the nine attached Merlin 1D booster rockets -- both of which have been destroyed and have sunk into the ocean in past launches.  This clever recycling -- if successful -- would tremendously cut costs and would give SpaceX the potential for much quicker turnarounds.  While it would not be possible for flights that are already pushing the fuel envelope (like commercial and military satellite launches to higher orbits), it would allow for reuse in many missions, including the ISS resupply missions.

SpaceX first attempted the daft maneuver in Sept. 2013 from a launch site in California, but was stymied when a high roll rate led to too much fuel being used.  SpaceX subsequently added a series of fins to stabilize the stage during its hypersonic descent, a design it nicknames the "X Wing".  

Space X hypersonic wings
SpaceX's paddle-looking hypersonic wings deploy during the descent to prevent roll and fuel waste.

Using the new design it has already scored soft landings of the first stage booster section of the Falcon 9 v1.1 rocket twice in 2014 -- once in April and once in July.  In the July landing, the rocket approached the ocean surface upright and braked, before losing its balance and belly flopping into the sea disintigrating.

Tuesday's launch was set to be the first platform soft-landing attempt.  The plan was to attempt to plant on a barge 200 miles northeast of the launch site, floating in the Atlantic.

SpaceX preps Falcon 9
The Falcon 9 and automated Dragon capsule are prepped for the mission on Monday.

The maneuver is a tricky one, admittedly, according to SpaceX.  The company wrote in a  press release about its plan:

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 (2,900 mph), 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 (2,900 mph) to about 250 m/s (559 mph). 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 (4.5 mph).

The craft has added four legs built of high-strength, lightweight honeycomb aluminum alloy pipes and carbon fiber panels.  The legs span roughly 70 feet and will be deployed just moments before touchdown.

SpaceX Falcon 9's legs
The SpaceX Falcon 9 v1.1 has special honeycomb aluminum alloy legs, reinforced with carbon fiber, which will deploy during the landing to stabilize the craft on the landing platform.

The landing site is a massive barge -- in this case a vessel called "the Marmac 300" prepped and launched from Jacksonville, Flor.  The craft is roughly the size of a football field at 100 feet wide and 300 feet long.

SpaceX barge landing

SpaceX barge landing
The hope is to land the first stage of the craft safely on the Marmac 300 barge.

At a forum at the Massachusetts Institute of Technology (MIT), company CEO, financier, and founder Elon Musk stated:

It’s probably not more than a 50 percent chance or less of landing it on the platform for the first time.  There are at least a dozen launches that will occur over the next 12 months, and I think it’s quite likely — probably 80 to 90 percent likely — that one of those flights we’ll be able to land and refly.

The plan is to burn the multi-engine upper stage for three minutes (as normal) then enter a hypersonic descent into the atmosphere firing a subset of the 9 Merlin 1D boosters on the first stage a total of three times, to brake.  The craft will then attempt to touchdown in a hard landing on a barge 200 miles northeast of the launch site, floating in the Atlantic.

The craft was on the launch pad at NASA's Cape Canaveral, Flor. launch facility when an automated abort sequence was triggered initiating the scrub process just a minute before launch.  SpaceX's 14 person launch team believed that "actuator drift" in the Falcon 9 rocket's thrust vector control steering system triggered the abort, potentially saving the rocket from a messy failure

SpaceX Falcon 9
The Falcon 9 launch was scrubbed just a minute before it would have launched, early Tuesday morning.

That left the 208 foot craft, which measures roughly 12 feet in diameter, dead on the ground, draining its some 1.05 million pounds of kerosene and liquid oxygen (LOX) fuel.  Engineers are trying to fix the issue with the second stage's flight control systems and prep the Falcon 9 for a second try at its launch on Friday.

If Friday's launch proceeds as hoped, SpaceX will have accomplished something no other spacefaring company or government space agency has achieved.  SpaceX is already among the few to test boost reuse on short terrestrial flights.  Thus far only NASA, though, had landed a booster that travelled to space.  And SpaceX's scheme of rocket braking would be a first as NASA's booster reuse -- applied to the now defunct Space Shuttle's booster engines -- was accomplished via massive parachutes.

Even if SpaceX can pull off the ambitious scheme, it still faces one lingering concern -- intellectual property., Inc. (AMZN) cofounder Jeff Bezos has a rival space company called Blue Origin, which last year filed a patent on sea-based landing platform technology -- U.S. Patent No. 8,678,321.  The filing opens the door to potentially suing SpaceX and collecting royalties.

Blue Origin patent
Blue Origin has patented oceanic soft landings.  SpaceX is unhappy, citing prior art, and has filed suit.

SpaceX has filed a lawsuit over the filing claiming prior art from past plans.  If the patent sticks, though, SpaceX could be forced to pay big bucks for soft landings -- or scrap the plan altogether.  

Blue Origin itself may be banking on that, as its own rocket are much cruder that SpaceX's at present and it's far from actually testing the scheme it's patenting in the real world.  In other words, Blue Origin's idea is just a brainstorm backed up by some simple ground tests, but it could stifle SpaceX's actual attempt to achieve the feat in the real world -- but that's the U.S. patent system for you.

Source: SpaceX [webcast]

"And boy have we patented it!" -- Steve Jobs, Macworld 2007

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