FAA moves closer to SpaceX permit for DragonFly testing

by Chris Gebhardt

The U.S. Federal Aviation Administration (FAA) has issued a draft environmental impact report on SpaceX’s request for an experimental license to use the McGregor Rocket Test Facility in Texas to test DragonFly – a prototype, low-altitude rocket-powered test vehicle designed to allow potential propulsive-landings of SpaceX’s Dragon spacecraft.

DragonFly testing and license application to the FAA:

In the realm of spaceflight, the recovery and reusability of flight rocket/spacecraft technologies has been a staple of American spaceflight since the Mercury Program of the 1960s, even though it only rose to prominence in the public mindset with the commencement of the Space Shuttle Program in the 1970s.

Since that time, the recovery and reusability of key components of flight rocket technologies has provided engineers with concrete, viewable, and tangible access to space-flown equipment – access to which has greatly improved reliability and safety within America’s various space vehicles.

Following in this tradition of safety and continuous improvement, SpaceX is currently developing new technologies to allow for the recovery (and reusability) of their own spacecraft systems – including the Falcon 9 rocket’s first stage and the Dragon capsules – under their Reusable Rocket Technology Development Program for cargo- and passenger-carrying Dragon missions.

Z9With site testing at McGregor forming the backbone of SpaceX’s initial testing of new rocket recovering technologies, the company is looking to add to its already successful testing of the F9R and Grasshopper technologies with DragonFly. 

Simply, DragonFly is a propulsive system designed to allow the SpaceX Dragon capsule to perform propulsive landings (both with and without parachute assistance). 

Overall, DragonFly will use eight SuperDraco hypergolic engines capable of producing up to 16,400 lbf of thrust each. 

For DragonFly testing, these engines will operate at a 15,325 lbf of thrust each for vehicle stability considerations and will burn a combination of monomethylhydrazine (MMH) and nitrogen tetroxide (NTO). 

The engines will be arranged in a “redundant pattern to support fault-tolerance in the propulsion system design,” meaning DragonFly will have redundancy in its propulsive landing system.

In all, SpaceX has proposed, and submitted to the FAA for commercial experimental license, a total of 30 DragonFly tests at its McGregor test facility

Z5Four of the test flights involve DragonFly being dropped from a helicopter at an altitude of 10,000 ft with two propulsive assist landings (parachutes and engines) and two propulsive landings (engines only).

The remaining 26 of the proposed test flights will launch from a specially-built pad that will take between 1-2 weeks to construct (according to the FAA draft environmental report). 

These 26 flights will consist of eight parachute-assist landings and 18 full propulsive hops (rocket engines only).

The need for and results of the draft report:

To gain permission for this test flight series, SpaceX had to apply for an experimental flight permit with the FAA.

In accordance with U.S. federal rules and regulations, the FAA has performed a series of examinations to determine the acceptability of DragonFly testing. Among these investigations was an environmental assessment of DragonFly testing impacts to the local and global environment. 

Z7The extensive, 76-page draft environmental report of the FAA, released this month, details 10 overall environmental factors that came into consideration. 

Specifically, those factors included air quality; noise and compatible land use; Department of Transportation Act Section 4 governing public parks, recreation areas, refuges, and significant historical sites; historical, architectural, archeological, and cultural resources; fish, wildlife, and plants; water quality; natural resource and energy supply; light emissions and visual impacts; and socioeconomic, environmental justice, children’s environmental health risks, and safety risks.

Of these 10 major areas, only two (2) were noteworthy enough for inclusion in the report’s “Cumulative Impacts” summary. 

These two concerns were air quality and noise.

Z8For the air quality concerns, the draft FAA report states, “DragonFly RLV (Reusable Launch Vehicle) testing operations would result in a very small increase in criteria pollutant emissions in the vicinity of the McGregor test site.”

Specifically, the FAA’s draft report notes the use of hypergols as part of the engine testing operations. 

“As part of their ongoing engine testing operations, SpaceX has begun an engine test program where they fire hypergolic propellants in open air for a maximum total of four minutes per year, and may have no open air testing at all in some years.”

Overall, the two hypergols, MMH and NTO, produce the byproducts of nitrogen gas and water.

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According to the FAA draft report, the combustion of these two hypergols “would have no effect on air quality.”

Z9Furthermore, the draft report notes that “No other existing or planned emissions sources were identified in the vicinity of the McGregor test site that would produce notable cumulative air quality impacts.”

Moreover, none of the proposed DragonFly tests currently fall under the National Environmental Policy Act’s (NEPA’s) greenhouse gases (GHG) thresholds for “significance,” and the calculated GHG emissions from DragonFly testing is close to zero percent of the U.S. annual total: 9.67 metric tons of carbon dioxide per year (DragonFly) compared to 6.708 billion tons per year (U.S. 2011).

Z11However, while the DragonFly GHG emissions themselves would not cause any appreciable global warming effects, they would increase the overall concentration of GHGs in Earth’s atmosphere and “in combination with past and future emissions from all other sources, contribute incrementally to the global warming that produces the adverse effects of climate change.”

Nonetheless, there is no way to currently estimate the specific impacts that these incremental changes, produced by DragonFly, would have on the local and/or global climate.

Thus, there is no environmental impact to air quality as defined and reported by the FAA for the DragonFly experimental license. 

Likewise, the noise considerations examined by the FAA also land on the positive side for SpaceX and DragonFly. 

Grasshopper testAccording to the FAA draft report, “The noise generated from DragonFly launch operations … would be similar to the types of noise routinely generated at the McGregor test site.

“When the Proposed Action is combined in conjunction with past, present, and reasonably foreseeable future actions at the McGregor test site and the surrounding area, no significant impacts would be expected.”

With this positive environmental impact report, SpaceX is one step closer to obtaining its experimental license for DragonFly. 

A final environmental report is still pending; however, issuance of a license by the FAA is expected in the near future – with DragonFly testing to begin in late-2014 and run through 2015.

(Images via SpaceX and the FAA).

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