Document ID: FAA-2012-0045-0010
Agency: faa
Document Type: Proposed Rule
Title: Exclusion of Tethered Launches from Licensing Requirements
Posted Date: 2014-07-22T04:00Z

[Federal Register Volume 79, Number 140 (Tuesday, July 22, 2014)]
[Proposed Rules]
[Pages 42475-42483]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-16954]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 400 and 401

[Docket No.: FAA-2012-0045; Notice No. 12-05A]
RIN 2120-AJ90

Exclusion of Tethered Launches From Licensing Requirements

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (SNPRM).

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SUMMARY: On August 23, 2012, the FAA published a notice of proposed 
rulemaking (NPRM) to exclude certain tethered launches from the FAA's 
licensing and permitting requirements. The FAA is issuing this SNPRM 
because a commenter raised an issue regarding toxic propellants that 
was not discussed in the NPRM, but should be addressed. Therefore, the 
FAA is issuing this action, which proposes to amend the NPRM so that 
tethered launches using propellants that cause serious injury to the 
public would not be eligible for exclusion. This SNPRM also includes 
clarifications based on recommendations commenters made to the NPRM. 
These proposed changes are intended to enhance the safety of tethered 
launches and improve regulatory effectiveness.

DATES: Send comments on or before September 22, 2014.

ADDRESSES: Send comments identified by docket number FAA-2012-0045 
using any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the online instructions for sending your 
comments electronically.
     Mail: Send comments to Docket Operations, M-30; U.S. 
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room 
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery or Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building

[[Page 42476]]

Ground Floor at 1200 New Jersey Avenue SE., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: The FAA will post all comments it receives, without 
change, to http://www.regulations.gov, including any personal 
information the commenter provides. Using the search function of the 
docket Web site, anyone can find and read the electronic form of all 
comments received into any FAA docket, including the name of the 
individual sending the comment (or signing the comment for an 
association, business, labor union, etc.). DOT's complete Privacy Act 
Statement can be found in the Federal Register published on April 11, 
2000 (65 FR 19477-19478), as well as at http://DocketsInfo.dot.gov.
    Docket: Background documents or comments received may be read at 
http://www.regulations.gov at any time. Follow the online instructions 
for accessing the docket or go to the Docket Operations in Room W12-140 
of the West Building Ground Floor at 1200 New Jersey Avenue SE., 
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this proposed rule, contact Stewart Jackson, AST-300, Office of 
Commercial Space Transportation, Federal Aviation Administration, 800 
Independence Avenue SW., Washington, DC 20591; telephone (202) 267-
7903; email Stewart.Jackson@faa.gov. For legal questions concerning 
this proposed rule, contact Sabrina Jawed, AGC-250, Office of the Chief 
Counsel, Federal Aviation Administration, 800 Independence Avenue SW., 
Washington, DC 20591; telephone (202) 267-8839; email 
Sabrina.Jawed@faa.gov.

SUPPLEMENTARY INFORMATION:

Authority for This Rulemaking

    The Commercial Space Launch Act of 1984, as amended and re-codified 
at 51 U.S.C. 50901-50923 (the Act), authorizes the Department of 
Transportation and thus the FAA, through delegations, to oversee, 
license, and regulate commercial launch and reentry activities, and the 
operation of launch and reentry sites as carried out by U.S. citizens 
or within the United States. 51 U.S.C. 50904, 50905. The Act directs 
the FAA to exercise this responsibility consistent with public health 
and safety, safety of property, and the national security and foreign 
policy interests of the United States. 51 U.S.C. 50905. Section 
50901(a)(7) directs the FAA to regulate only to the extent necessary, 
in relevant part, to protect the public health and safety and safety of 
property. The FAA is also responsible for encouraging, facilitating, 
and promoting commercial space launches by the private sector. 51 
U.S.C. 50903.

I. Overview of SNPRM

    In its August 23, 2012 NPRM (77 FR 50956), the FAA proposed to 
exclude certain tethered launches from chapter III requirements if the 
tethered launches met specified safety criteria. The proposed criteria 
did not address the use of toxic propellants onboard a launch vehicle. 
During the NPRM comment period, the FAA received a comment stating the 
agency should revise the proposed rule to protect the public from the 
potential harm exposure to a toxic propellant could cause. The FAA 
agrees that it should address toxic propellants. Therefore, this SNPRM 
proposes that if an operator chooses to use any of the toxic 
propellants identified in Tables I417-2 and I417-3 in Appendix I of 
part 417, that launch must meet chapter III requirements.
    Also, this SNPRM includes two clarifications to the NPRM. First, 
the agency would remove the term ``established strength properties'' 
from proposed Sec.  400.2(c)(2)(i) to better clarify the proposed 
requirement and preserve the original intent, which is to ensure that 
the tether system can withstand the maximum dynamic load placed on it. 
Second, the FAA would revise proposed Sec.  400.2(c)(2)(iii) to clarify 
that the maximum flight limit of 75 feet for a tethered launch vehicle 
would be measured from the ground to a fully-extended tether's 
attachment point to a vertically-oriented vehicle.

II. Background

A. Summary of NPRM

    In August 2012, the FAA issued an NPRM proposing to exclude 
tethered launches that met specified requirements for a safe launch 
from chapter III licensing, permitting, and waiver requirements. The 
NPRM proposed defining a tether system as a device that contains launch 
vehicle hazards by physically constraining a launch vehicle in flight 
to a specified range from its launch point. It would include all 
components, from the point where the tether attaches to the vehicle to 
a solid base, that experience load during a tethered launch. The NPRM 
proposed that the tether system had to:
     Have established strength properties that would not yield 
or fail under the maximum dynamic load on the system or two times the 
maximum potential engine thrust;
     have a minimum safety factor of 3.0 for yield stress and 
5.0 for ultimate stress;
     constrain the launch vehicle within 75 feet above ground 
level;
     display no damage prior to the launch; and
     be insulated or located such that it would not experience 
thermal damage from the launch vehicle exhaust.
    The NPRM additionally proposed separation distances for the 
tethered operation based on the amount of propellant onboard a launch 
vehicle. Those distances are listed in proposed Table A of the NPRM. 
Lastly, the NPRM proposed requiring that the launch vehicle be 
unmanned, have a liquid or hybrid motor, and carry no more than 5,000 
pounds of propellant.

B. Summary of Comments

    The comment period for the NPRM closed on October 22, 2012. The FAA 
received comments from three commercial space companies: Masten Space 
Systems, Inc. (Masten); Unreasonable Rocket; and, SpeedUp, LLC. In 
addition, the agency received comments from four individuals, making a 
total of seven commenters. Two of the seven commenters, SpeedUp, LLC 
and Mr. W. Andrew Shrader, supported the proposal. The other commenters 
raised issues that are summarized and discussed below.
Toxic Propellants
    The FAA did not address toxic propellants in the NPRM. One 
commenter, Mr. Chad W. Thrasher, suggested that the FAA consider the 
harmful characteristics of some liquid propellants. He pointed out that 
many liquid rocket propulsion systems use liquids that are animal 
carcinogens, corrosive, and potentially explosive when mixed in 
specific ratios. He also pointed out that exposure to certain 
propellants may result in damage to the lungs, liver, kidneys, the 
central nervous system, and may also result in coma or death by 
asphyxiation. Mr. Thrasher suggested that the FAA revise proposed Sec.  
400.2(c)(3) to ensure that operators and the public are upwind of the 
test location or at least twice the distance defined in proposed Table 
A if downwind.
    Mr. Thrasher proposed protecting the operators themselves. The 
Commercial Space Launch Act of 1984, as amended and re-codified at 51 
U.S.C. 50901-50923, authorizes the agency through delegation to 
regulate launch and reentry activities to ensure the public

[[Page 42477]]

health and safety, safety of property, and the national security and 
foreign policy interests of the United States. Public safety as defined 
in Sec.  401.5 refers to the safety of people and property that are not 
involved in supporting the launch. Therefore, the proposal is not 
intended to protect the launch operator or the launch operator's 
personnel who are involved in carrying out the launch.
    As this proposal pertains to the public, the FAA agrees with Mr. 
Thrasher that the NPRM should have addressed the harmful 
characteristics of certain propellants. However, the agency believes 
the best solution to keeping the public safe and retaining the burden-
relieving components of the proposal would be to exclude from chapter 
III requirements only those eligible tethered launches that do not use 
propellants that cause serious injury. Mr. Thrasher suggested changing 
the proposed rule by stating that Table A would apply only if one is 
upwind of the test location. He suggested that if one is downwind of 
the test location, one should be at least one and a half times the 
separation distances stated in Table A. Basing the separation distances 
on wind direction, and increasing the separation distances for anyone 
standing downwind of the test location would add a level of complexity 
to the proposal that the FAA does not intend. Thus, the agency would 
amend proposed Sec.  400.2(c)(1)(iii) \1\ to clarify that chapter III 
continues to apply to a tethered launch using toxic propellants listed 
in Table I417-2 and Table I417-3 in Appendix I of part 417. If launch 
operators wish to use a toxic propellant, they would still be required 
to conduct their launch under chapter III.
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    \1\ In the NPRM, Sec.  400.2(c)(1)(iii) proposed to limit the 
amount of fuel the launch vehicle could carry to 5,000 pounds. For 
the SNPRM, this proposed requirement would be moved to new paragraph 
(c)(1)(iv) of Sec.  400.2.
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Established Strength Properties
    The FAA would withdraw the proposed requirement that a tether 
system eligible for exclusion from chapter III requirements possess 
``established strength properties.'' Section 400.2(c)(2)(i) of the NPRM 
proposed that an eligible tether system have established strength 
properties that would not yield or fail under the conditions listed in 
Sec. Sec.  400.2(c)(2)(i)(A) and 400.2 (c)(2)(i)(B). One commenter, Mr. 
Alexander Salvato, suggested that the phrase ``established strength 
properties'' was too vague, and it was not clear how the strength 
properties of the tether system would be established, or by whom. He 
suggested clarifying the phrase with substitute language or integrating 
the alternate test for tether strength provided in the NPRM.
    The FAA agrees that the phrase ``established strength properties'' 
is too vague for the reasons Mr. Salvato provided, and no longer 
proposes it because the remainder of the provision would address the 
FAA's concerns with sufficient specificity. New proposed Sec.  400.2 
(c)(2)(i) would require that an eligible tether system not yield or 
fail under (1) the maximum dynamic load exerted on the system, or (2) a 
load equivalent to two times the maximum potential engine thrust.
Factors of Safety
    For the tether system, the FAA proposes a minimum factor of safety 
of 3.0 for yield stress and 5.0 for ultimate stress. Three commenters, 
Masten, Mr. Thrasher, and Mr. Salvato, expressed concern about the 
FAA's proposed factors of safety.
    Masten commented that while the proposed factors of safety may be 
appropriate for military development applications, they place 
unnecessary financial and schedule burdens on commercial reusable 
launch vehicle (RLV) developers without materially increasing public 
safety. Masten also stated the performance characteristics of 
commercial RLVs are driven by market rather than military requirements. 
As a result, the robust attachment hardware that may be required for a 
tether system with a yield stress safety factor of 3.0 and an ultimate 
stress safety factor of 5.0 may prove heavier than can reasonably be 
flown by a commercial RLV under tether test conditions. Masten 
suggested the proposed factors of safety may be appropriate for 
military development purposes, where ordnance or weapons systems 
requirements may drive a need for reliance on high yield and ultimate 
stress safety factors; however, commercially competitive RLV developers 
do not face the same military-based performance, maintainability, and 
interoperability requirements that U.S. Air Force developers address. 
Commercial RLV developers do face financing and price competition 
challenges that are not present in military system development. Masten 
suggested that based on its extensive experience designing and 
operating RLVs and tether systems, a safety factor of 2.0 for yield 
stress and 4.0 for ultimate stress would be consistent with commercial 
RLV operator practices and would ensure the tether system design was 
sufficiently safe but not so robust as to inhibit meaningful tether 
test activity.
    The FAA acknowledges that its proposed factors of safety are also 
used for military applications. However, the FAA does not agree that 
the proposed factors of safety should be revised because they are too 
stringent for commercial operations. In addition to the U.S. Air Force, 
academia, and NASA have also recommended or used the proposed factors 
of safety. In 1948, Joseph P. Vidosic established guidelines that 
recommended when to apply a factor of safety ranging from 1.25 to 4.0 
based on yield strength.\2\ Since then, various industries have 
accepted these guidelines as basic guidance that can be used when 
experience and empirical data are otherwise not available. For brittle 
material, these guidelines recommend doubling the factor of safety for 
yield strength. With better known materials that are to be used in 
uncertain environments or subjected to uncertain stresses, the 
guidelines recommend using a factor of safety of 3 to 4. NASA used a 
factor of safety of 3 for yield and 5 for ultimate stress for its 
lifting slings.\3\ Similarly, the U.S. Air Force uses a minimum factor 
of safety of 3 for yield stress and 5 for ultimate stress for design of 
ground-based systems, including tether systems.\4\ Furthermore, several 
engineering textbooks contain the same factor of safety guidelines.\5\
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    \2\ Joseph P. Vidosic, ``Design Stress Factors,'' Proceedings of 
the American Society for Engineering Education, Vol. 55, 1947-48, pp 
653-658.
    \3\ NASA STD 8719.9, ``Standard for Lifting Devices and 
Equipment,'' May 2, 2002.
    \4\ Air Force Space Command Manual 91-710, Air Force Space 
Command, Range Safety User Requirement Manual, Vol. 3 (July 1, 
2004).
    \5\ C.S. Sharma and Kamlesh Purohit, Design of Machine Elements 
(2005); Rajendra Karwa, A Testbook of Machine Design (2005); Richard 
M. Phelan, Fundamentals of Mechanical Design (1957).
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    As noted previously, the goal of this rulemaking is to maintain 
public safety while relieving the industry and the FAA from chapter III 
licensing, permitting, and waiver requirements for tethered launches. 
Because the FAA would not be overseeing the tethered launches covered 
under the proposed rule, and because of the inherent uncertainties of 
the test environment, the agency believes it is reasonable to impose 
conservative design requirements to ensure the public is protected from 
a potential accident or incident. The factors of safety the FAA 
proposed (3.0 for yield stress, which is the elastic limit; and, 5.0 
for ultimate stress, which is where breakage occurs) are based on 
guidance from academia, from successful usage by NASA, and proven 
results as documented by the U.S. Air Force's application to its 
operations at the Eastern and Western Ranges involving tethered and 
ground-

[[Page 42478]]

based systems. Thus, the proposed factors of safety would render FAA 
oversight unnecessary.
    The FAA does not agree with Masten that it will be too costly for 
commercial companies to comply with these factors of safety. To the 
contrary, selecting conservative factors allows an operator to avoid 
the cost of analysis associated with FAA oversight. The selection of an 
appropriate factor of safety is based on the level of uncertainties 
regarding loading conditions, material properties, and environmental 
factors. The criteria used to select the factor of safety is based on 
accumulated knowledge associated with the design of the system, 
historical empirical knowledge, engineering judgment, judgment based on 
experience, and best practices that ensure safety. The factors of 
safety applied in industries such as aviation and aerospace reflect 
years of experience and the accumulation of empirical test data that 
provide an in-depth understanding of how loading conditions affect the 
system. Since 1948, engineers in various industries, including the 
aircraft and spacecraft industries, have achieved a better 
understanding of how to obtain factors of safety values for various 
loading conditions by implementing expensive, high fidelity validation 
and verification testing.
    Typically, aircraft and spacecraft industries perform high fidelity 
verification and validation testing of vehicle structures to ascertain 
how these structures will perform under actual load conditions and to 
address how to reduce uncertainties. These test results provide an 
understanding of the actual loading characteristics associated with the 
system. With a significant reduction in uncertainties, an operator 
could reduce the factors of safety values. To achieve these lower 
factors of safety values, an operator would have to conduct a thorough 
structure analysis and high cost test programs. For example, if a 
vehicle attached to a tether started flying erratically and became 
uncontrollable, an operator would need to conduct costly testing to 
determine the worst loading condition. However, an operator could use 
closed-loop analyses and the proposed factors of safety to address 
uncertainties at lower cost without compromising public safety. With 
higher factors of safety, it is possible to reduce the need for high 
fidelity testing and analysis with a resulting reduction in costs. The 
FAA is not proposing a high fidelity analysis, and is instead focused 
on factors that protect public safety while making FAA oversight 
unnecessary.
    Mr. Thrasher commented that the NPRM incorrectly interprets the 
intended minimum safety factor of the tether system by selecting the 
case requiring the highest, most conservative safety factors. He 
pointed out that the Martino report \6\ the FAA cited in the NPRM 
references three case studies. The first case addresses the expected or 
nominal loads based on the expected thrust levels in the desired 
direction with the proper dispersions. For this case, Mr. Thrasher 
suggested that the safety factors of 3.0 for yield stress and 5.0 for 
ultimate stress should be used for the expected nominal loads. He 
stated that in most cases this would be 100 percent of the thrust level 
of the system. The second case addresses structures designed to 
restrain a system during testing. He stated the second case provides 
safety factors if the structure is actually tested to designated loads, 
and another set of safety factors if it is just analyzed but not 
tested. He stated the second set of safety factors is more conservative 
to allow for minor errors in the structural analysis. He suggested that 
the third case, using safety factors of 2.0 for yield stress and 3.0 
for ultimate stress, should be used in off-nominal cases. The proposed 
method to calculate the maximum dynamic load by multiplying the maximum 
potential engine thrust by a factor of two is consistent with an off-
nominal event such as an explosion. Mr. Thrasher stated the tether 
system must satisfy all three load cases--nominal, ground structures, 
and off-nominal--and, systems must be designed to meet the case with 
the highest design loads. Mr. Thrasher further commented that to 
determine the highest design loads of a system, one must calculate each 
case, and then use the highest loads for both yield and ultimate 
stress. Based on his calculations, he stated that the proposed rule 
would require the tether system to withstand a 33 percent greater yield 
load and a 40 percent greater ultimate stress load to those recommended 
in the Martino report. He recommended that the FAA revise proposed 
Sec.  400.2(c)(2) as follows:
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    \6\ Nicholas E. Martino, Design and Analysis Guidelines for 
Launch Vehicle Tether Systems, Aerospace Report No. ATR-2008 (5377)-
1, The Aerospace Corporation (Sept. 30, 2007). This report is 
available in the docket for this rulemaking (Docket No. FAA-2012-
0045).
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    (2) Tether system. The tether system must--
    (i) Have established strength properties that will not yield or 
fail under--
    (A) The maximum dynamic load of the system; and
    (B) The nominal maximum dynamic load on the system with a safety 
factor of 3.0 for yield stress and 5.0 for ultimate stress; and
    (C) The off-nominal dynamic load cases, calculated as the 
equivalent to two times the maximum potential engine thrust, shall have 
a minimum safety factor of 2.0 for yield stress and 3.0 for ultimate 
stress.
    In the NPRM, the FAA used the Martino Report to show that a factor 
of safety of 3 for yield stress and 5 for ultimate stress are accepted 
industry standards for the design of ground-based systems, including a 
tether and its attachments to launch facilities or ground equipment. 
The FAA did not intend to adopt all the load cases discussed in the 
Martino Report. Instead, the FAA strives to achieve simplicity and 
clarity in its proposed rule without compromising safety. Because the 
FAA would not provide oversight for eligible tethered launches, the FAA 
selected robust and industry-acceptable factors of safety that would 
not necessitate FAA scrutiny.
    Mr. Salvato stated the term ``safety factor'' is too vague. He said 
although the FAA discusses in the NPRM what the terms ``yield stress'' 
and ``ultimate stress'' mean, the agency only references factor of 
safety in its supplementary materials. He recommended including an 
abbreviated definition in the regulation of safety factor based on the 
more lengthy definition contained in the supplemental material, or 
referencing the attached supplemental material in the preamble to the 
rule.
    The FAA does not believe it is necessary to define the term 
``safety factor'' in the rule because it is a widely recognized 
industry term. However, the agency offers the following brief 
explanation to clarify the term as it is used in the preamble 
discussion: The factor of safety (FoS), also called safety factor (SF), 
is the ratio of the maximum load that a system is expected to withstand 
against the allowable design load applied or the ratio of absolute 
strength (structural capacity) to actual applied design load.
Yield Stress
    In the preamble to the NPRM, the FAA stated that yield stress is 
the point of the elastic limit. Unreasonable Rocket generally supported 
the rule, but was unclear as to why the FAA described the tether yield 
point as the point of elastic limit instead of the point of plastic 
limit for a system that is meant to be stretchy. It stated that all of 
Unreasonable Rocket's testing used climbing rope designed to yield 
(i.e., to arrest a climber's fall without snapping

[[Page 42479]]

him in half). It then recommended the FAA define yield stress in the 
rule as the point of plastic yield.
    The FAA does not agree. Elastic limit is the maximum stress that 
may be developed such that there is no permanent or residual 
deformation (the elements subjected to the loading; for example, the 
tether dynamic rope) when the load is entirely removed. The FAA 
proposed yield stress for the tether system as the elastic limit rather 
than the plastic limit because once the plastic limit is reached, the 
elastic capability of the material ends and permanent deformation 
occurs. If the applied load continues to increase, the element will 
weaken and ultimately breakage will occur.\7\
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    \7\ Stephen W. Attaway, Rope System Analysis (1996); William 
Storage and John Ganter, Physics for Cavers: Loads, and Energy (1990 
& 1998); Tendon, Dynamic and Static Ropes Manual.
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Flight Altitude Limit
    In the NPRM, the FAA proposed to confine an eligible launch to one 
constrained within 75 feet above ground level (AGL). Two commenters 
asked the FAA to increase the proposed flight limit, but the FAA does 
not agree. As the agency discussed in the NPRM, to determine a safe 
flight limit, the FAA calculated the average length of a tether (32 
feet) and the average height of a crane/forklift (43 feet) and added 
the two figures together. These averages are based on historical data 
from past tethered launches. The FAA also used a random sampling of the 
height of cranes/forklifts from various manufacturers to help determine 
the average crane/forklift height.
    Two commenters, Masten and Mr. Thrasher, stated that the proposed 
flight limit is too restrictive and should be increased. Masten 
recommended increasing the flight limit by 275 feet to 350 feet AGL to 
accommodate existing and contemplated commercial tether launch 
activities, which would include larger, higher-performance RLVs. Mr. 
Thrasher suggested increasing the maximum allowable tether length to 40 
feet to avoid ground effects from the propulsion system, and increasing 
the flight limit by 15 feet to 90 feet AGL to account for longer tether 
lengths and slightly larger than average cranes.
    Masten pointed out that to comply with the proposed flight limit, 
the combined length of the launch vehicle, the vehicle connection, the 
tether and the fixed connection could not exceed a 37.5-foot radius 
from the fixed connection to the end of the launch vehicle, and that 
this threshold would severely limit the availability of the proposed 
exclusion to larger and higher-performance RLVs.
    The FAA does not agree with this reasoning. First, the length of 
the launch vehicle would not be included in the flight limit 
calculation, as described in greater detail below. Second, regarding 
Masten's concern that the proposed flight limit would not account for 
larger, higher-performance RLVs, the FAA's intent is to provide design 
and operational criteria for the safe tethered launch of small, liquid 
or hybrid propulsion launch vehicles similar to those for which the 
agency has issued past waivers. It is not the agency's intent to 
exclude from FAA oversight the larger, higher-performance launch 
vehicles Masten describes in its comment, specifically Morpheus, 
Minuteman, and XEUS.
    In response to Mr. Thrasher's comment suggesting the FAA increase 
the maximum allowable tether length, the FAA notes that the NPRM 
explicitly states that launch operators are not required to use the 
same measurements for tether length and crane/forklift height in their 
tether system design that the agency used to calculate the proposed 
flight limit. Even so, they would still be required to comply with the 
maximum flight limit threshold in order to be excluded from chapter III 
requirements. For example, an operator could use a 10-foot crane and a 
30-foot tether, or a 50-foot crane and a 25-foot tether. In both 
scenarios, the maximum flight limit would not exceed 75 feet AGL. If an 
operator needed to adjust its tether length to avoid ground effects 
from the propulsion system, as Mr. Thrasher suggested, it would be free 
to do so as long as the vehicle did not exceed the flight limit for 
exclusion from chapter III.
    Mr. Thrasher also suggested increasing the maximum flight limit 15 
feet to account for longer tether lengths and slightly larger than 
average cranes. The FAA does not agree that increasing the flight limit 
15 feet is a necessary or beneficial change from the proposed rule. The 
proposed 75-foot flight limit is adequate for vehicles that are 
equivalent in height to the average size of those vehicles for which 
the FAA granted a launch waiver to conduct tethered launches in the 
past. Also, Mr. Thrasher did not provide any rationale that addresses 
the FAA's safety concerns in support of his proposal. The FAA also 
reiterates that its intention is not to exclude larger than the average 
size of those vehicles that the FAA granted a launch waiver from 
chapter III requirements.
    Additionally, the agency wishes to clarify the proposed threshold 
for flight limit. In the NPRM, proposed Sec.  400.2(c)(2)(iii) stated 
the tether system would ``constrain the launch vehicle within 75 feet 
above ground level.'' The FAA now proposes to clarify that the 
restriction would measure from the ground to the point where the tether 
attaches to the vehicle. To calculate whether a launch vehicle exceeded 
the proposed threshold, the operator would measure from the ground to 
the tether's attachment point to a vertically oriented vehicle. In 
other words, if the attachment point was to the launch vehicle's base, 
the nose of the launch vehicle could be at an altitude greater than 75 
feet. The maximum flight limit would not include the height of the 
vehicle itself.
Slack Tether
    The FAA proposed that a tether system be able to withstand the 
maximum dynamic load on the system or a load equivalent to two times 
the maximum potential engine thrust. One commenter, Mr. Andrew Swallow, 
suggested that ``rules are needed to permit slack tethers, such as 
defining their breaking strength, as well as tethers under static 
load.'' He also stated that a tethered vehicle starts and stops on the 
ground so will need a few inches of slack. The FAA would permit a 
tethered launch vehicle to be eligible to be excluded from chapter III. 
A slack tether may, in some circumstances, allow loading in excess of 
the proposed criteria. A slack tether, particularly a static rope, 
could increase the magnitude of the applied load placed on the tether 
system because the velocity of the vehicle would quickly eliminate the 
slack, and the tether could rapidly decelerate the vehicle. This rapid 
deceleration would cause the vehicle and the tether system to be 
subjected to high dynamic loading called shock loading. Shock is 
produced when an object (e.g., a launch vehicle) in motion suddenly 
halts.\8\ Shock loading can produce as much as twice the load impact 
compared to static loading.\9\ The force produced by the sudden 
stoppage of motion could in some cases cause not just damage to the 
tether or vehicle, but tether separation, because it would exceed the 
maximum produced loads.
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    \8\ Stephen W. Attaway, Rope System Analysis (1996); William 
Storage and John Ganter, Physics for Cavers: Loads, and Energy (1990 
& 1998); Tendon, Dynamic and Static Ropes Manual.
    \9\ A. E. H. Love, Mathematical Theory of Elasticity, 2nd ed., 
Cambridge University Press (1906), pgs. 179-180.
---------------------------------------------------------------------------

    If the tether system could not withstand the dynamic load exerted 
on it and was damaged, and if tether separation occurred and the launch

[[Page 42480]]

vehicle exceeded the flight limit, the operator would have failed to 
comply with two key proposed requirements: (1) Ensuring the tether 
system could withstand the specified dynamic load placed on it; and (2) 
constraining the launch vehicle to the maximum flight limit. 
Additionally, the FAA does not agree that a vehicle starts and stops a 
tethered launch on the ground. An operator could elect to suspend the 
vehicle in the air. The FAA does not believe it is necessary to add 
requirements for the use of slack tethers to the proposed rule because 
the rule requires the tether design to sustain dynamic (or shock) 
loading conditions.
Inspection of Tether System
    Proposed Sec.  400.2(c)(2)(B)(iv) \10\ would require that a tether 
system not display damage prior to the launch. In the NPRM's preamble, 
the FAA provided guidance on conducting a visual inspection of the 
tether system to identify damage such as component fatigue, fracture, 
and wear.
---------------------------------------------------------------------------

    \10\ In the NPRM (77 FR 50959), in section heading (C)(4), the 
FAA inadvertently cited the proposed rule paragraph as Sec.  
400.2(c)(3). The correct proposed paragraph is Sec.  400.2(c)(2).
---------------------------------------------------------------------------

    One commenter, Mr. Thrasher, suggested that the FAA require a 
launch operator to inspect tether hardware because the FAA is relying 
on visual inspections to ensure there is no component damage. Mr. 
Thrasher also recommended that effective inspections of metal 
components for pre-existing damage, fracture, corrosion, and wear 
require all surfaces to be bare metal or have clear protective 
coatings. Further, he noted that any paint or improperly bonded 
covering used to prevent thermal damage could prevent detection of 
damage. He proposed that any thermal protective coverings be installed 
after inspection and any components that require thermal protection be 
bonded, be visually inspected, and used only one time. He recommended 
revising proposed Sec.  400.2(c)(2)(B)(iv) to add the following: 
``Metal components must be inspected unpainted and free of any 
coverings or coatings that would interfere with visual inspection. Any 
metal using bonded protective thermal coatings shall be visually 
inspected and used only one time.''
    Mr. Thrasher's comment implies the FAA intended the visual 
inspection to be a primary means of ensuring the structural integrity 
of the tether system. The FAA's intent for the visual inspection is to 
provide an added measure of safety to reinforce the safety criteria the 
agency is proposing. Primary among these safety requirements are the 
proposed conservative factors of safety. The FAA does not intend for 
the visual inspection to be a primary means of determining if the 
tether system is safe. The expectation is the operator will conduct a 
visual inspection on the eve of the launch, after full compliance with 
all other required design and operational criteria. However, this does 
not preclude launch operators from conducting a more substantive 
inspection if they believe it is necessary to ensure compliance and a 
safe tethered launch.

IV. Regulatory Notices and Analyses

A. Regulatory Evaluation

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 and Executive Order 13563 direct 
that each Federal agency shall propose or adopt a regulation only upon 
a reasoned determination that the benefits of the intended regulation 
justify its costs. Second, the Regulatory Flexibility Act of 1980 (Pub. 
L. 96-354) requires agencies to analyze the economic impact of 
regulatory changes on small entities. Third, the Trade Agreements Act 
(Pub. L. 96-39) prohibits agencies from setting standards that create 
unnecessary obstacles to the foreign commerce of the United States. In 
developing U.S. standards, the Trade Act requires agencies to consider 
international standards and, where appropriate, that they be the basis 
of U.S. standards. Fourth, the Unfunded Mandates Reform Act of 1995 
(Pub. L. 104-4) requires agencies to prepare a written assessment of 
the costs, benefits, and other effects of proposed or final rules that 
include a Federal mandate likely to result in the expenditure by State, 
local, or tribal governments, in the aggregate, or by the private 
sector, of $100 million or more annually (adjusted for inflation with 
base year of 1995). This portion of the preamble summarizes the FAA's 
analysis of the economic impacts of this proposed rule.
    Department of Transportation Order DOT 2100.5 prescribes policies 
and procedures for simplification, analysis, and review of regulations. 
If the expected cost impact is so minimal that a proposed rule does not 
warrant a full evaluation, this order permits a statement to that 
effect and the basis for it to be included in the preamble if a full 
regulatory evaluation of the cost and benefits is not prepared. Such a 
determination has been made for this proposed rule. The reasoning for 
this determination is discussed below.
    The FAA has licensing authority over tethered launches, which are 
considered launches under chapter III unless they meet the definition 
of an amateur rocket launch.\11\ To conduct such tethered non-amateur 
rocket launches, operators must obtain a launch license, experimental 
permit, or apply for a waiver from chapter III. Applying for waivers, 
licenses, and permits impose a financial burden on vehicle operators 
and the FAA because of time and resources required to create and 
analyze these applications.
---------------------------------------------------------------------------

    \11\ Launches of amateur rockets are excluded from the 
requirements of chapter III. See 14 CFR 400.2 (2011).
---------------------------------------------------------------------------

    The proposed rule would establish clear and simple criteria for an 
effective tether system. In addition, it proposes vehicle and 
operational criteria as added measures to protect the public in the 
event of a tether system failure. Operators would not have to apply for 
a launch license, permit, or waiver from chapter III to conduct 
tethered launches of non-amateur rockets \12\ that met the proposed 
criteria for an effective tether system and the vehicle and operational 
criteria. Operators that met the proposed criteria would not have to 
incur the costs of applying for a launch license, permit, or waiver and 
would not have to sustain the costs associated with delay in the 
processing of these applications. The FAA would not have to conduct 
case-by-case analyses of tethered launches that met the proposed 
criteria to verify public safety from a launch vehicle explosion or 
confirm that the tether system would not fail. Furthermore, launch 
operators that conducted tethered launches would not be compelled to 
follow the criteria in this proposal as they would still have the 
option of applying for a launch license, permit, or waiver under 
chapter III. Therefore, the proposed rule would impose no additional 
requirements on operators, but would provide an alternative to 
conducting a tethered launch under chapter III. If the operator deemed 
it more cost effective to apply for a license, permit, or waiver than 
to follow the criteria proposed here, the operator would have that 
option.
---------------------------------------------------------------------------

    \12\ Operators launching amateur rockets on a tether would still 
be subject to part 101 of chapter I and would continue to be 
excluded from chapter III.
---------------------------------------------------------------------------

    For the reasons discussed, the rule would be cost relieving to both 
operators and the FAA. The FAA requested but received no comments on 
its conclusion in the NPRM that the rule would be cost relieving to 
operators and the FAA.
    This SNPRM revises the FAA's original proposal by not excluding 
from

[[Page 42481]]

chapter III tethered launches that use specified toxic propellants from 
chapter III requirements. Even with the change, the rule is still cost 
relieving relative to the current regulations, even though tethered 
launches using toxic fuel must comply with chapter III requirements as 
they currently do. There would be no additional costs or cost savings 
due to the change to the NPRM. Operators launching vehicles that are 
eligible for the chapter III exclusion would still benefit from cost 
savings relative to the current chapter III requirements. The FAA has 
determined that this proposed rule is not a ``significant regulatory 
action'' as defined in section 3(f) of Executive Order 12866, and is 
not ``significant'' as defined in DOT's Regulatory Policies and 
Procedures.

B. Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA) 
establishes as a principle of regulatory issuance that agencies shall 
endeavor, consistent with the objectives of the rule and of applicable 
statutes, to fit regulatory and informational requirements to the scale 
of the businesses, organizations, and governmental jurisdictions 
subject to regulation. To achieve this principle, agencies are required 
to solicit and consider flexible regulatory proposals and to explain 
the rationale for their actions to assure that such proposals are given 
serious consideration. The RFA covers a wide-range of small entities, 
including small businesses, not-for profit organizations, and small 
governmental jurisdictions. Agencies must perform a review to determine 
whether a rule will have a significant economic impact on a substantial 
number of small entities. If the agency determines that it will, the 
agency must prepare a regulatory flexibility analysis as described in 
the RFA.
    However, if an agency determines that a rule is not expected to 
have a significant economic impact on a substantial number of small 
entities, section 605(b) of the RFA provides that the head of the 
agency may so certify and a regulatory flexibility analysis is not 
required. The certification must include a statement providing the 
factual basis for this determination, and the reasoning should be 
clear.
    This proposed rule is expected to provide an alternative to 
conducting tethered launches under chapter III and therefore could 
alleviate the financial burden of applying for a launch license, 
permit, or waiver to chapter III if an operator met the proposed 
criteria. The expected outcome would therefore have either a cost 
saving impact or no impact on small entities affected by the proposed 
rule. Under this SNPRM, launches that use toxic propellants would have 
to comply with chapter III, which they have to do currently. Although 
the changes introduced with the SNPRM might reduce the number of launch 
vehicles that would be exempt from chapter III, the rule would still 
have either a cost saving impact or no impact on small entities. The 
FAA did not receive comments when it reached the same conclusion in the 
NPRM.
    Therefore, as provided in section 605(b), the head of the FAA 
certifies this rulemaking will not result in a significant economic 
impact on a substantial number of small entities.

C. International Trade Impact Assessment

    The Trade Agreements Act of 1979 (Pub. L. 96-39), as amended by the 
Uruguay Round Agreements Act (Pub. L. 103-465), prohibits Federal 
agencies from establishing standards or engaging in related activities 
that create unnecessary obstacles to the foreign commerce of the United 
States. Pursuant to these Acts, establishing standards is not 
considered an unnecessary obstacle to the foreign commerce of the 
United States, so long as the standard has a legitimate domestic 
objective, such as the protection of safety, and does not operate in a 
manner that excludes imports that meet this objective. The statute also 
requires consideration of international standards and, where 
appropriate, that they be the basis for U.S. standards. If a foreign 
launch operator were to conduct a tethered launch in the United States 
that meets the requirements of this proposed rule, it would be eligible 
for the proposed exclusion from chapter III. The FAA has assessed the 
potential effect of this proposed rule and determined that it would 
have the same impact on domestic and international entities and thus 
have a neutral trade impact.

D. Unfunded Mandates Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare a written statement 
assessing the effects of any Federal mandate in a proposed or final 
agency rule that may result in an expenditure of $100 million or more 
(in 1995 dollars) in any one year by State, local, and tribal 
governments, in the aggregate, or by the private sector; such a mandate 
is deemed to be a ``significant regulatory action.'' The FAA currently 
uses an inflation-adjusted value of $151.0 million in lieu of $100 
million. This proposed rule does not contain such a mandate; therefore, 
the requirements of Title II of the Act do not apply.

E. Paperwork Reduction Act

    The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires 
that the FAA consider the impact of paperwork and other information 
collection burdens imposed on the public. The FAA has determined that 
there would be no new requirement for information collection associated 
with this proposed rule.
    Public comments: The FAA did not receive comments to the NPRM on 
its determination that the proposed rule would not impose new paperwork 
requirements.

F. International Compatibility

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA policy to conform to 
International Civil Aviation Organization (ICAO) Standards and 
Recommended Practices to the maximum extent practicable. No ICAO 
Standards and Recommended Practices correspond to these proposed 
regulations.

G. Environmental Analysis

    FAA Order 1050.1E identifies FAA actions that are categorically 
excluded from preparation of an environmental assessment or 
environmental impact statement under the National Environmental Policy 
Act in the absence of extraordinary circumstances. This rulemaking 
action qualifies for the categorical exclusion identified in paragraph 
312f and involves no extraordinary circumstances.

V. Executive Order Determinations

A. Executive Order 12866

    See the ``Regulatory Evaluation'' discussion in the ``Regulatory 
Notices and Analyses'' section elsewhere in this preamble.

B. Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule under the principles and 
criteria of Executive Order 13132, Federalism. The agency has 
determined that this action would not have a substantial direct effect 
on the States, or the relationship between the Federal Government and 
the States, or on the distribution of power and responsibilities among 
the various levels of government, and, therefore, would not have 
Federalism implications.

[[Page 42482]]

C. Executive Order 13211, Regulations That Significantly Affect Energy 
Supply, Distribution, or Use

    The FAA analyzed this proposed rule under Executive Order 13211, 
Actions Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use (May 18, 2001). The agency has determined that it 
would not be a ``significant energy action'' under the executive order 
and would not be likely to have a significant adverse effect on the 
supply, distribution, or use of energy.

VI. Additional Information

A. Comments Invited

    The FAA invites interested persons to participate in this 
rulemaking by submitting written comments, data, or views. The agency 
also invites comments relating to the economic, environmental, energy, 
or federalism impacts that might result from adopting the proposals in 
this document. The most helpful comments reference a specific portion 
of the proposal, explain the reason for any recommended change, and 
include supporting data. To ensure the docket does not contain 
duplicate comments, commenters should send only one copy of written 
comments, or if comments are filed electronically, commenters should 
submit only one time.
    The FAA will file in the docket all comments it receives, as well 
as a report summarizing each substantive public contact with FAA 
personnel concerning this proposed rulemaking. Before acting on this 
proposal, the FAA will consider all comments it receives on or before 
the closing date for comments. The FAA will consider comments filed 
after the comment period has closed if it is possible to do so without 
incurring expense or delay. The agency may change this proposal in 
light of the comments it receives.
    Proprietary or Confidential Business Information: Do not file 
proprietary or confidential business information in the docket. Such 
information must be sent or delivered directly to the person identified 
in the FOR FURTHER INFORMATION CONTACT section of this document, and 
marked as proprietary or confidential. If submitting information on a 
disk or CD ROM, mark the outside of the disk or CD ROM, and identify 
electronically within the disk or CD ROM the specific information that 
is proprietary or confidential.
    Under 14 CFR 11.35(b), if the FAA is aware of proprietary 
information filed with a comment, the agency does not place it in the 
docket. Proprietary information is held in a separate file to which the 
public does not have access, and the FAA places a note in the docket 
that it has received it. If the FAA receives a request to examine or 
copy this information, it treats it as any other request under the 
Freedom of Information Act (5 U.S.C. 552). The FAA processes such a 
request under Department of Transportation procedures found in 49 CFR 
part 7.

B. Availability of Rulemaking Documents

    An electronic copy of rulemaking documents may be obtained from the 
Internet by--
    1. Searching the Federal eRulemaking Portal (http://www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies Web page at http://www.faa.gov/regulations_policies or
    3. Accessing the Government Printing Office's Web page at http://www.gpo.gov/fdsys/.
    Copies may also be obtained by sending a request to the Federal 
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence 
Avenue SW., Washington, DC 20591, or by calling (202) 267-9680. 
Commenters must identify the docket or notice number of this 
rulemaking.
    All documents the FAA considered in developing this proposed rule, 
including economic analyses and technical reports, may be accessed from 
the Internet through the Federal eRulemaking Portal referenced in item 
(1) above.

List of Subjects

14 CFR Part 400

    Space transportation and exploration, Licensing, Safety.

14 CFR Part 401

    Space transportation and exploration.

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration proposes to amend chapter III of title 14, Code of 
Federal Regulations as follows:

PART 400--BASIS AND SCOPE

0
1. The authority citation for part 400 continues to read as follows:

    Authority: 51 U.S.C. 50901-50923.

0
2. Revise Sec.  400.2 to read as follows:

Sec.  400.2  Scope.

    These regulations set forth the procedures and requirements 
applicable to the authorization and supervision under 51 U.S.C. 
subtitle V, chapter 509, of commercial space transportation activities 
conducted in the United States or by a U.S. citizen. The regulations in 
this chapter do not apply to--
    (a) Space activities carried out by the United States Government on 
behalf of the United States government;
    (b) The launch of an amateur rocket as defined in Sec.  1.1 of this 
title; or
    (c) A launch of a tethered launch vehicle that meets the following 
criteria:
    (1) Launch vehicle. The launch vehicle must--
    (i) Be unmanned;
    (ii) Be powered by a liquid or hybrid rocket motor;
    (iii) Not use any of the toxic propellants of Table I417-2 and 
Table I417-3 in Appendix I of part 417 of this chapter; and
    (iv) Carry no more than 5,000 pounds of propellant.
    (2) Tether system. The tether system must--
    (i) Not yield or fail under--
    (A) The maximum dynamic load on the system; or
    (B) A load equivalent to two times the maximum potential engine 
thrust.
    (ii) Have a minimum safety factor of 3.0 for yield stress and 5.0 
for ultimate stress.
    (iii) Constrain the launch vehicle within 75 feet above ground 
level as measured from the ground to the attachment point of the 
vehicle to the tether.
    (iv) Display no damage prior to the launch.
    (v) Be insulated or located such that it will not experience 
thermal damage due to the launch vehicle's exhaust.
    (3) Separation distances. The launch operator must separate its 
launch from the public and the property of the public by a distance no 
less than that provided for each quantity of propellant listed in Table 
A of this section.

           Table A--Separation Distances for Tethered Launches
------------------------------------------------------------------------
                                                         Distance (ft.)
              Propellant carried (lbs.)                 from the launch
                                                             point
------------------------------------------------------------------------
1-500................................................                900
501-1,000............................................              1,200
1001-1,500...........................................              1,350
1,501-2,000..........................................              1,450
2,001-2,500..........................................              1,550
2,501-3,000..........................................              1,600
3,001-3,500..........................................              1,650
3,501-4,000..........................................              1,700
4,001-4,500..........................................              1,750
4,501-5,000..........................................              1,800
------------------------------------------------------------------------

PART 401--ORGANIZATION AND DEFINITIONS

0
3. The authority citation for part 401continues to read as follows:

    Authority: 51 U.S.C. 50101-50923.

[[Page 42483]]

0
4. Amend Sec.  401.5 by adding the definition of Tether system in 
alphabetical order to read as follows:

Sec.  401.5  Definitions.

* * * * *
    Tether system means a device that contains launch vehicle hazards 
by physically constraining a launch vehicle in flight to a specified 
range from its launch point. A tether system includes all components, 
from the tether's point of attachment to the vehicle to a solid base, 
that experience load during a tethered launch.
* * * * *

    Issued in Washington, DC, on July 9, 2014.
George C. Nield,
Associate Administrator, Commercial Space Transportation.
[FR Doc. 2014-16954 Filed 7-21-14; 8:45 am]
BILLING CODE 4910-13-P