ASTM F3658-23

• Abstract:

  SIGNIFICANCE AND USE; 5.1 This guide is intended to be used by design teams developing suborbital space vehicles. It contains a consensus of the design topics known through experience of the technical community to be the minimum to which attention must be paid during the design process to ensure a high probability of safe flight and return to Earth of humans.; SCOPE; 1.1 This guide addresses the design of suborbital space vehicles that carry flight crew, spaceflight participants, mission specialists or other humans on suborbital trajectories. ; 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. ; 1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

• Status: Published
• Publication Date: 31-Jul-2023
• Technical Committee: F47 - Commercial Spaceflight
• Drafting Committee: F47.01 - Occupant Safety

• Refers: ASTM F3668/F3668M-23 - Standard Guide for Occupant Survivability in Orbital Vehicles
• Effective Date: 01-Oct-2023

Overview

ASTM F3658-23: Standard Guide for Crewed Suborbital Space Vehicle Design provides consensus-based guidance for organizations and design teams engaged in the development of suborbital space vehicles intended to carry humans, including flight crew, mission specialists, and spaceflight participants. The standard applies to both new and existing suborbital vehicle designs and outlines essential practices recognized through industry experience and regulatory frameworks to increase flight safety and successful return to Earth.

This ASTM standard supports commercial spaceflight by summarizing lessons learned and best practices tailored to human occupancy, focusing on occupant protection, system reliability, and emergency response. The guide was developed in accordance with major international standardization principles as recognized by the WTO TBT Committee.

Key Topics

ASTM F3658-23 addresses a comprehensive range of topics critical to the design and operation of crewed suborbital space vehicles, emphasizing:

• Human Needs and Accommodations

  • Provision of atmospheric conditions suitable for human life and critical operations
  • Management and containment of biological and wet waste
  • Availability of emergency survival equipment and supplies, including first aid and communication devices

• Human Protection

  • Protection from acceleration, vibration, radiation, noise, and mechanical hazards
  • Systems for fire detection, suppression, and emergency response to contaminated atmospheres or loss of cabin pressure
  • Procedures for occupant escape and emergency egress

• Flight Worthiness

  • Fault tolerance in the presence of catastrophic hazards, with specific guidelines for redundant systems and structural integrity
  • Material and process compatibility to minimize risks such as toxic exposure or fire
  • Environmental requirements ensuring functionality across natural and induced conditions

• Human/Vehicle Integration

  • Ergonomic considerations tailored to occupants’ physical interaction with vehicle systems
  • Provision for clear communication between crew, occupants, and ground controllers
  • Support for manual override of automated systems during safety-critical scenarios

• Testing and Demonstration

  • Requirements for qualification and environmental testing exceeding maximum operating conditions
  • Mandate for flight demonstration before operation with human occupants and post-modification testing

Applications

ASTM F3658-23 is an essential resource in various commercial and research contexts involving crewed suborbital spaceflight. It is directly applicable to:

• Commercial Spaceflight Vehicle Manufacturers
  Assists in developing safe, reliable suborbital vehicles capable of carrying passengers, mission specialists, or researchers.

• Aerospace Design Teams and Engineers
  Provides baseline criteria for safety-critical systems, environmental controls, occupant accommodations, and vehicle integration.

• Space Tourism Operators
  Outlines safety and emergency management expectations for flights carrying spaceflight participants.

• Regulatory Compliance and Certification
  Supports alignment with international and federal human spaceflight safety recommendations and aids in regulatory review processes.

• Research Institutions and Space Agencies
  Helps guide the development of suborbital research platforms intended for human occupancy.

Related Standards

For a holistic approach to human safety in crewed space vehicles, reference the following standards and guidelines:

• ASTM F3668/F3668M: Guide for Occupant Survivability in Orbital Vehicles
• FAA Recommended Practices for Human Space Flight Occupant Safety, Version 1.0
• ASTM F3377: Terminology Relating to Commercial Spaceflight

Additional related standards may include those covering flight worthiness, failure tolerance, occupant safety, crew escape, and safety-critical system design in aerospace contexts.

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Keywords: suborbital space vehicle design, crewed spaceflight, occupant safety, flight worthiness, emergency procedures, human protection, ASTM F3658-23, commercial space vehicle standards, human/vehicle integration, aerospace safety guidelines

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F3658 − 23
Standard Guide for
Crewed Suborbital Space Vehicle Design
This standard is issued under the fixed designation F3658; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope F3668/F3668M Guide for Occupant Survivability in Orbital
Vehicles
1.1 This guide addresses the design of suborbital space
3.2 Federal Aviation Association Standards:
vehicles that carry flight crew, spaceflight participants, mission
FAA Recommended Practices for Human Space Flight
specialists or other humans on suborbital trajectories.
Occupant Safety Version 1.0, Dated August 27, 2014.
1.2 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Terminology
priate safety, health, and environmental practices and deter-
4.1 Definitions:
mine the applicability of regulatory limitations prior to use.
4.1.1 abort, v—terminate the launch countdown, especially
1.3 This international standard was developed in accor-
in the automated portion late in the countdown.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4.1.2 egress, n—scenario where the flight crew/spaceflight
Development of International Standards, Guides and Recom-
participants depart the space vehicle on the ground through the
mendations issued by the World Trade Organization Technical
outer hatch and onto the launch tower/pad.
Barriers to Trade (TBT) Committee.
4.1.3 escape, n—separation of the crewed space vehicle
from its launch vehicle/booster in an off-normal scenario to
2. Purpose
avoid a hazardous condition.
2.1 The purpose of this guide is to serve as a consensus
4.1.4 failure tolerance, n—the ability to sustain a certain
among the commercial spaceflight technical community as to
number of failures and still retain capability; a component,
key practices associated with the design of human-occupied
subsystem, or system that cannot sustain at least one failure is
suborbital space vehicles. The guide was created based on
not considered to be failure tolerant.
industry best practices, historical lessons learned, and existing
safety requirements, and is intended to apply to both new and 4.1.5 safety critical function or item, n—one whose func-
existing suborbital space vehicles. Use of this guide does not
tions are essential to safe performance or operation; a safety-
purport to address all safety concerns associated with human critical system subsystem, condition, event, operation, process,
space flight aboard suborbital space vehicles, but instead
or item is one whose proper recognition, control, performance,
provides a set of industry consensus best design practices to or tolerance is essential to system operation such that it does
mitigate known safety risks associated with human flight
not jeopardize crew, occupant, or public safety.
aboard suborbital space vehicles. Companies developing sub-
4.1.6 vehicle, n—that portion of a space flight system that is
orbital space vehicles are expected to tailor the recommenda-
intended to fly to, operate in, or return from space; this includes
tions herein to fit the specific requirements of their systems and
any launch vehicle, carrier aircraft, equipment, and supplies,
mission profiles.
but excludes payloads.
3. Referenced Documents
5. Significance and Use
3.1 ASTM Standards:
5.1 This guide is intended to be used by design teams
F3377 Terminology Relating to Commercial Spaceflight
developing suborbital space vehicles. It contains a consensus
of the design topics known through experience of the technical
This guide is under the jurisdiction of ASTM Committee F47 on Commercial
Spaceflight and is the direct responsibility of Subcommittee F47.01 on Occupant community to be the minimum to which attention must be paid
Safety.
during the design process to ensure a high probability of safe
Current edition approved Aug. 1, 2023. Published November 2023. DOI:
flight and return to Earth of humans.
10.1520/F3658-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from https://www.faa.gov/about/office_org/headquarters_offices/ast/
the ASTM website. media/recommended_practices_for_hsf_occupant_safety-version_1-tc14-0037.pdf.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F3658 − 23
6. Basis of Classification safety-critical operations can be performed successfully. Sys-
tem design should consider both audible and infrasonic and the
6.1 The recommendations below reflect the practices iden-
combined noise level of multiple acoustic sources.
tified in the “FAA Recommended Practices for Human Space
7.2.5 Mechanical Hazards Protection—The system should
Flight Occupant Safety,” Version 1.0, Dated August 27, 2014.
be designed to protect occupants from serious injuries and to
Where appropriate, additional recommendations have been
ensure no interference with the successful performance of
added to cover topics not covered by the FAA document, but
safety-critical operations due to:
which are included in the scope of this document.
7.2.5.1 Moving parts;
7. Recommendations:
7.2.5.2 Entrapment;
7.1 Human Needs and Accommodations: 7.2.5.3 Stored potential energy;
7.1.1 Atmospheric Conditions: 7.2.5.4 Burrs;
7.1.1.1 The vehicle should provide atmospheric conditions
7.2.5.5 Pinch points;
to all occupants adequate to protect them from serious injury
7.2.5.6 Sharp edges;
and allow safety-critical operations to be performed.
7.2.5.7 Sharp items; and
7.1.1.2 The system should provide the capability to monitor
7.2.5.8 Temperature.
and react to Environmental conditions.
7.2.6 Orthostatic Protection—The system should provide
7.1.2 Body Waste, Vomitus, Biological Waste and Wet Trash
orthostatic intolerance countermeasures to the extent necessary
Management—The system should provide a means to contain
to protect occupants from serious injury and perform safety-
body waste, vomitus, biological waste, and wet trash to protect
critical operations.
occupants from illness and prevent interference with opera-
7.2.7 Fire Event Detection and Fire Suppression—A fire can
tions.
quickly put the occupants into extremis. The absence of
7.1.3 Emergency Survival Equipment and Supplies—The
ventilation, the permeation of combustion products in a zero-g
system should include emergency survival equipment and
environment, and the limited source of emergency breathing
supplies that provide a reasonable chance of survival and
air to supplement the environment until the toxic gasses can be
rescue of all occupants for postlanding emergencies. Unless
purged combine to make a zero-g fire uniquely dangerous. To
unnecessary for the design reference mission, the emergency
provide the maximum chance of occupant survival following a
survival equipment and supplies should include items from
fire, spacecraft should, at a minimum, provide the following
each of the following categories:
fire mitigations:
7.1.3.1 First aid;
7.2.7.1 Fire detection system that senses combustion prod-
7.1.3.2 Communications (Refer to 7.3.10, Emergency Oc-
ucts from the primary environmental control system flow path;
cupant Location Post-Landing and 7.3.11, Emergency Com-
7.2.7.2 Means to suppress credible fire types given the
munication with Rescue Personnel.);
known fuel and combustion sources;
7.1.3.3 Flotation (if operating over water beyond glide
7.2.7.3 Automatic or manual ventilation system cutoff to
distance from land);
prevent fire propagation; and
7.1.3.4 Signaling; and
7.1.3.5 Environmental Protection. 7.2.7.4 Personal Breathing Apparatus (PBA) to offset effect
of the combustion products.
7.2 Human Protection:
7.2.8 Emergency Response to Contaminated
7.2.1 Acceleration Protection—The system should be de-
Atmosphere—In order to respond to a contaminated
signed to limit occupant exposure to transient and sustained
atmosphere, the system should provide equipment and provi-
linear and angular acceleration such that occupants are pro-
sions to limit occupant exposure to the contaminated atmo-
tected from loss of consciousness or serious injuries and
sphere such that occupants are protected from serious injuries
safety-critical operations can be performed successfully.
and safetycritical operations can be performed successfully.
7.2.2 Vibration Protection—The system should be designed
Specific mitigations should be dependent on the conditions
to limit occupant exposure to vibration such that occupants are
present such as:
protected from serious injuries and safety-critical operations
7.2.8.1 Provide breathable air and eye protection for each
can be performed successfully.
occupant.
7.2.3 Radiation Protection—The system should be designed
7.2.9 Emergency Response to Loss of Cabin Pressure—In
to limit occupant exposure to radiation by following the
the event cabin pressure integrity is lost, the system should be
ALARA (As Low As Reasonably Achievable) radiation prin-
designed to prevent incapacitation of flight crew and serious
ciple. At minimum, the system should protect occupants from
injury to the occupants. See 7.7 of Guide F3668/F3668M,
serious injuries and allow for safety critical operations to be
Standard Guide for Occupant Safety of Orbital Vehicles for
performed successfully. System design should consider the
specific recommendations.
solar cycle, solar particle events, and all sources of ionizing
radiation both internal and external to the vehicle. 7.2.10 Emergency Response—Escape and Egress. The sys-
7.2.4 Noise Exposure Protection—The system should be tem should provide the capability for the occupants to self-
designed to limit occupant exposure to continuous, egress from the vehicle on the ground. The system should
intermittent, and impulse noise such that occupants are pro- provide continuous ascent escape capability from pre-lift-off
tected from permanent hearing loss or serious injuries and through the end of powered flight.
F3658 − 23
7.3 Flight Wor
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