CCT-REQ-1130_Rev_F.docx

National Aeronautics and Space Administration

ISS Crew Transportation and Services Requirements Document

Original signed by

September 6, 2017

Kathryn L. Lueders

Date

Manager, Commercial Crew Program

Record of Revision/Changes

CR 0164 -Limited set of changes to capture selected standards updates, clarifications identified through iCap and CPC contracts and JPRCB direction to implement the full pressurized Cargo IRD.

3/23/2015

Table of Contents

1.0 Introduction

Under the guidance of processes provided by Crew Transportation Plan (CCT-PLN-1100), this document with its sister documents, Crew Transportation Technical Management Processes (CCT-PLN-1120), Crew Transportation Technical Standards and Design Evaluation Criteria (CCT-STD-1140), and Crew Transportation Operations Standards (CCT-STD-1150), and International Space Station (ISS) to Commercial Orbital Transportation Services Interface Requirements Document (SSP 50808), provides the basis for a National Aeronautics and Space Administration (NASA) certification for services to the ISS for the Commercial Provider. When NASA Crew Transportation System (CTS) certification is achieved for ISS transportation, the Commercial Provider will be eligible to provide services to and from the ISS during the services phase of the NASA Commercial Crew Program (CCP).

The CTS has two top-level objectives in support of the NASA mission of providing services to the ISS. The primary objectives are to provide for crew rotation capability for four NASA or NASA-sponsored crewmembers, henceforth called NASA crew, and to provide for an emergency crew return capability for these crewmembers at any time while the commercial spacecraft is docked to the ISS. Secondary objectives include transporting a limited amount of ISS Program-specified pressurized cargo to the ISS, returning pressurized cargo from the ISS, and providing for a crew safe haven capability when the spacecraft is docked to the ISS. The Design Reference Mission (DRM) for ISS can also be found in CCT-DRM-1110.

The spacecraft will be capable of transporting NASA crew to the ISS and docking 24 hours after launch. Mission launch opportunities must be accomplished within NASA-specified timeframes to accommodate ongoing ISS science operations and to minimize ISS traffic model impacts associated with other visiting vehicles. Prior to launch, the CTS supports a NASA-provided pre-launch health stabilization program for NASA crew. The CTS also assures comparable health stabilization for any other crewmembers. Within a few hours of launch, NASA completes their crew medical assessments and baseline data collection process in NASA-provided facilities and hands the crew over to the CTS provider for transportation to the launch site. The NASA flight surgeons will serve as the physicians for the NASA crew during all phases of flight.

Lift-off occurs when the launch site passes through the ISS’s orbital plane. Daily launch opportunities then depend on the resulting phasing; an everyday launch opportunity is desirable, but not required. Launch and ascent into the 51.6 degree inclination must meet Range Safety constraints associated with the launch site. Following ascent, an orbital insertion maneuver is executed and becomes the first of several orbital rendezvous maneuvers to be performed. These maneuvers bring the spacecraft closer towards the ISS. ISS standard communications are used when the spacecraft closes to within tens of kilometers to the ISS and ship-to-ship voice communications are established. Relative navigation is performed by the spacecraft using available cooperative and non-cooperative assets on the ISS. Communication and telemetry monitoring will be shared between the Commercial Vehicle Control Center (CVCC) and the ISS mission control facilities, Mission Control Center - Houston (MCC-H). MCC-H Mission Authority will be established to ensure ISS, spacecraft, and crew safety. When in close proximity to the ISS, after receiving approval from both the spacecraft and MCC-H, the spacecraft begins a final approach to a NASA-specified docking port on the ISS. After docking, the vestibule between the ISS and the spacecraft is pressurized and verified not to be leaking. The spacecraft hatches are opened and the crew transfers into the ISS, placing the newly arrived spacecraft in a quiescent state.

If the nominal docking attempt is not successful, or if an anomaly occurs near docking which would prevent docking at the nominal opportunity, the spacecraft backs out to a short safe distance and performs necessary reconfigurations, followed by a second approach and docking attempt. If that docking is also unsuccessful, the spacecraft will separate from the ISS vicinity on a collision-free safe trajectory and the spacecraft will prepare for a final re-rendezvous and docking attempt on the following crew day. If this final docking attempt is unsuccessful, the mission will be terminated, and the crew will return to Earth.

Because of the short time duration from launch to docking, internal maintenance of the spacecraft should not be necessary, nor should the crew require certain complex habitability items for food and waste management that can be found on longer duration vehicles, like the Space Shuttle or the ISS.

Extravehicular Activity (EVA) will not occur because the complexity of preparing for and executing an EVA is precluded due to the short time in the spacecraft early in the mission. Similarly, EVA will not be performed during the short free-flight duration from undocking to landing.

The spacecraft will be designed to be attached to the ISS for 210 days, although nominal crew rotations will occur at approximately 180-day intervals. The spacecraft remains quiescent and requires minimal maintenance during docked operations. The CVCC will provide routine, periodic support for these docked operations, in association with MCC-H. The ISS will provide power and environmental resources to the spacecraft in order to maintain the vehicle in a return-to-Earth ready state.

Due to limitations in the number of docking ports on the ISS, the spacecraft may need to be relocated from one docking port to another during ISS increment operations to provide operational flexibility. To accomplish this relocation, the spacecraft’s full crew complement will ingress the spacecraft, close the hatch, and the spacecraft will be relocated from one port to the other port. The crew needs to be in the spacecraft to protect from the potential failure to re-mate with a docking port and preserve assured return for the crew.

When docked to the ISS, the spacecraft also provides a contingency “safe haven” capability allowing the crew to retreat to the spacecraft, close the hatch, and remain in a safe environment for up to 24 hours. If necessary, the spacecraft atmosphere will be purged during this activity. The ISS will provide attitude control during this 24-hour period. After the ISS returns to a habitable environment state, the crew will open the hatch and re-enter the ISS. If the ISS cannot achieve a habitable state during this period, the crew will return to Earth.

While docked to the ISS, the spacecraft will also serve as an emergency return vehicle for contingencies requiring the return of the crew brought to the ISS. Emergencies could result from ISS system failures, an uninhabitable crew environment, or a medical event requiring the return of the crewmembers. The crew will return to Earth within 24 hours of a declaration of an intention to return early. The crew will be fully trained to execute these contingency return-to-Earth operations, landing at a location where rescue is likely to be most expedient.

Due to the limited size and power available, the spacecraft is expected to have basic first aid and life support capability to respond to immediate medical conditions in the free-flight mode.

The launch of the next rotation mission may occur prior to the departure of the current increment crew working on the ISS, resulting in a handover period where two commercial spacecraft would be docked to the ISS for approximately 7 to 10 days. If the Commercial Provider has received NASA approval to fly non-NASA crew to the ISS, the spacecraft will need to provide food, water, clothing, Environmental Control and Life Support System (ECLSS) consumables, and other logistics for these crewmembers for the docked timeframe, since NASA does not generally pre-position these supplies on the ISS.

After handover is complete, the current increment crew will return in the spacecraft. They will enter the spacecraft, perform a vehicle health check, close hatches, depress the vestibule, perform a hatch leak check to verify seal integrity, and depart from the ISS. When available consumables permit, the spacecraft will potentially circumnavigate the ISS while in proximity to assess the external configuration of the ISS prior to final departure. During this circumnavigation, the crew will capture imagery to allow post-flight analysis of the ISS configuration.

The timeframe from undocking through landing is envisioned to be a short 4 to 8 hour free-flight duration. Landing will occur on the continental United States (U.S.) land mass or waters directly extending from the coast for nominal landing. This reduces risk by minimizing rescue force assets, increasing proximity to U.S. medical facilities, increasing security, and ensuring a prepared landing site free of hazards. If the nominal deorbit maneuver is waived-off after separation from the ISS, a subsequent landing at an alternate landing site, with nearby recovery forces, will be possible. The spacecraft may also perform orbital maneuvers in low Earth orbit (LEO) to better accommodate alternate landing sites. Returning crew will be deconditioned and potentially have impaired musculoskeletal, cardiopulmonary, and neurovestibular capabilities as a result of long duration exposure to the micro-gravity and space environment, resulting in degraded crewmember performance in the post-landing timeframe. Because of the deconditioned state of the crew, special considerations need to be provided for crew recovery, medical care, and other post-landing care activities.

Upon arrival at the landing location, the NASA crew will be met with a recovery crew that will assist the astronauts in egress operations and removal of time-critical cargo. NASA personnel will begin post-flight medical and science evaluations soon after egress is complete in a temporary facility at the landing location. Subsequently, the NASA flight crew, NASA support personnel, and time-critical cargo will be transported by a CTS element to a staging location where handover will be completed and the NASA crew and cargo will be flown back to Houston using NASA assets.

After recovery operations are complete, the spacecraft will be safed and transported to a location for subsequent post-flight evaluation.

1.1 Purpose

The purpose of this document, hereafter referred to as CCT-REQ-1130, is to provide the requirements for development (design, manufacturing, testing, qualification, production, and operation) of commercial services to deliver NASA crew and limited cargo to and from the ISS. The intent of this document is that all CTS requirements are to be fulfilled by the Commercial Provider; however, it may be more practical for NASA to provide the consumables or hardware associated with a particular function. This document clearly states when a function or hardware is the responsibility of NASA.

1.2 Scope

These services and design requirements were developed by the CCP and the ISS Program for the crew transportation system. This document is clearly divided into ISS destination services requirements in Section 3.1 and transportation certification requirements in Sections 3.2 through 3.11.

The CTS refers to all assets and services required to meet the requirements of CCT-REQ-1130, including pre-flight planning, trajectory and abort analysis, ground processing and manufacturing, ground operations, mission control, training, launch control, post-landing recovery operations, safety and mission assurance, and all other functions required for safe and successful human space flight missions. Other key definitions include integrated space vehicle, which will be used when discussing the launch vehicle and spacecraft. The spacecraft is also known as the “crewed element” and serves as the crew rescue or crew transfer vehicle, while the “launch vehicle” is the element that provides the propulsion systems necessary to transport the spacecraft to the desired insertion orbit. Another term that is utilized throughout this document is NASA crew, which consists of all crewmembers sponsored by NASA, including both International Partners (IP) and NASA astronauts.

1.3 Precedence

In the event of a conflict between the text of this document and references cited herein (listed in Section 2.0), the text of this document takes precedence. The exception to this statement is for SSP 50808, which takes precedence during ISS integrated operations. Nothing in this document supersedes applicable laws and regulations unless a specific exemption has been obtained.

In the event of conflict between this document and any spreadsheet exports of the NASA requirements database, the contents of this document take precedence.

1.4 Delegation of Authority

This document was jointly prepared by and will be jointly managed by the CCP and the ISS Program. The Joint Program Requirements Control Board (JPRCB) is the authority for baselining and approving changes to this document. CCT-REQ-1130 will be maintained in accordance with standards for the CCP documentation. The CCP is responsible for assuring the definition, control, implementation, and verification of the requirements identified in this document. Coordination with the ISS Program for verification and eventual certification of the requirements identified as ISS driven requirements will be performed through the CCP.

1.5 Verb Application and Document Detail

When used within the context of a requirement under a contract, statements in this document containing shall are used for binding requirements that must be verified and have an accompanying method of verification; will is used as a statement of fact, declaration of purpose, or expected occurrence; and should denotes an attribute or best practice which must be addressed by the system design. When used within the context of a reference document under an agreement, the verbs shall, will, and should are only intended as informational and are not binding.

In some cases, the values of quantities included in this document have not been confirmed and are designated as: “To Be Confirmed” (TBC) - still under evaluation, and “To Be Determined” (TBD) or “To Be Supplied” (TBS) - known, but not yet available. A "To Be Resolved" (TBR) is used when there is a disagreement on the requirement between technical teams. When a change in a noted characteristic is deemed appropriate, notification of the change shall be sent to the appropriate review and change control authority.

Each requirement in CCT-REQ-1130 is annotated by its section number. At the end of each requirement text is a requirement ID of the format R.CTS. This corresponds to the absolute ID in NASA’s requirements database. It can be used to cross reference requirements in this document to spreadsheet exports of the database. See Section 1.3 in the event of conflict between this document and spreadsheet exports.

2.0 Documents

The following design, manufacturing, testing, and quality control standards apply to all space flight hardware and software, including the launch vehicle, all portions of the spacecraft, and any launch abort system. There are also specific standards for ground support equipment (GSE), along with software standards for ground software that are needed to perform a primary mission objective, have direct interaction with human space flight systems, or have a direct impact on the health and safety of the crew.

NASA has identified three basic types of standards:

1. One type of standard must be followed completely with no deviation or alternative proposal. They are identified by the words “meet” within the corresponding sections of this document. Within the Applicable Documents list below these standards will be shown as fully applicable. Verification language for these technical standards that must be met can be found in Section 4.0 of this document. Any Applicable Document listed within these “meet” documents are considered to be “meet the intent of” documents and alternative standards can be proposed.

2. The majority of the standards identified are standards which use the language “meet the intent of.” These contain requirements that can be met explicitly by following the standard or by proposing alternate standards that meet or are consistent with the requirement levied in the NASA Standard. It should be understood that the applicable documents called out by “meet the intent of” standards from CCT-REQ-1130 are also considered “meet the intent of” standards. Within the Applicable Documents list below these standards will be shown as “Alternative Allowed.” Because these standards are unique, CCT-STD-1140 was developed to define some specific criteria utilized by NASA to evaluate and approve alternative standards. The process and product defined in the respective sections of CCT-STD-1140 define the details of how any proposed alternative standards will be evaluated along with the key aspects of items proposed as part of the verification. The Requirements Applicability Matrix in Section 2.1 of CCT-STD-1140 provides a mapping of the sections that discuss the details of each standard where an alternative is allowed. The specific verification language for each of these alternative standards will be partnered with NASA after an agreement is reached on the alternative standard. Verification language for these technical standards that must be met or complied with can be found in Section 4.0 of this document. Similar to Engineering Standards, Human System Integration Design Requirements are listed in Appendix Q and are invoked by the “meet the intent” requirement 3.10.1. Alternatives to the children requirements in Appendix Q can be proposed.

3. There are many other standards that may be utilized in the design and manufacturing process and for standard operations. These are the third type of NASA standard and many of these documents can be found in the reference documents in Section 2.2. These technical standards are reference and will have no verification language attached. CCT-STD-1150 was developed to define specific criteria for operations spanning the interval from integrated vehicle assembly, test, and integration at the launch site through recovery of NASA crew and cargo at the landing site(s). The products and processes defined in the respective sections of CCT-STD-1150 discuss in detail how operational standards will be evaluated.

2.1 Applicable Documents

Q.6.3, Q.6.3V

(5/25/01) with change 2, 3, and 4 12/2002

(6/1/06)

(6/1/06)

2.0

(8/1/09)

2222: A 2223: B

2224: BL

2225: BL

2226: BL

6012: C 6013: B

6015: BL

6016: BL

6017: BL

6018: A

(1/1/04)

IPC J-STD-001E

IPC J-STD-001ES

Amendment 1

ISO 2631-1: 1997

(11/08)

Allowed for Appendix Q

(10/97)

(11/08)

3.1.5.4, 4.3.1.5.4

(7/1/10)

MSFC-DWG-20M02540

(5/11/90)

(2/5/13)

(6/3/07)

(1/16/15)

5.6.3,

4.10.2 and 5.10.2 are not applicable Allowed

(1/7/08)

(3/12/12)

4.7, 4.8 Allowed

National Council on Radiation Protection and Measurements (NCRP) Report Number 132

Rev. 3 (7/12)

(3/1/11)

(6/3/94)

Q.2.1, Q.2.1V, Q.3.6V

4.3.4.1.1, Appendix P

(2/15)

4.3.1.3.1, 3.1.3.2, 4.3.1.3.2, 3.1.3.3, 4.3.1.3.3, 3.1.3.4, 4.3.1.3.4, 3.1.3.5, 4.3.1.3.5, 3.1.3.6, 4.3.1.3.6, 3.1.3.7, 4.3.1.3.7, 3.1.3.8, 4.3.1.3.8, 3.5.3.7, 4.3.5.3.7

2.2 Reference Documents

This section will provide a list of documents and technical and manufacturing standards that can be used as a reference during the launch vehicle, spacecraft, and ground system design activities. Additional reference documents for a variety of technical disciplines can be found in CCT-STD-1140.

10 CFR 20.1003

Title 10 – Energy; Chapter I -- Nuclear Regulatory Commission; Part 20 -- Standards for Protection Against Radiation; Subpart A -- General Provisions

ACGIH TLVs and BEI (2007)

American Conference of Governmental Industrial Hygienists (ACGIH) standard, Threshold Limit Values® and Biological Exposure Indices®

AFSPCMAN 91-710

Air Force Space Command Range Safety User Requirements

AGARD-CP-472

Development of Acceleration Exposure Limits for Advanced Escape Systems (Brinkley, J.W.; Specker, L.J.; Armstrong, H.G.; Mosher, S.E. (February 1990). AGARD-CP-472. Implications of Advanced Technologies for Air and Spacecraft Escape.)

AIAA-S-114

Space Systems – Moving Mechanical Assemblies for Space and Launch Vehicles, January 1, 2005 (provided as reference)

ASTM Manual 36

Safe Use of Oxygen and Oxygen Systems: Guidelines for Oxygen System Design, Materials Selection, Operations, Storage, and Transportation

CXP 70023

Constellation Program Design Specifications for Natural Environments (DSNE)

CXP 70044

Constellation Program Natural Environment Definition for Design (NEDD);

EARD

Exploration Architecture Requirements Document

FAA HFDS

Human Factors Design Standard

GIDEP S0300-BT-PRO-010

Government-Industry Data Exchange (GIDEP) Operations Manual

GIDEP S0300-BU-GYD-010

Government-Industry Data Exchange (GIDEP) Requirements Guide

GSFC-STD-1000

Goddard Space Flight Center Rules for the Design, Development, Verification, and Operation of Flight Systems

HRP-47072

Risk of Orthostatic Intolerance During Re-exposure to Gravity

IEEE 730-2002

Institute of Electrical and Electronic Engineers (IEEE) Standard for Software Quality Assurance Plans

IEEE C95.1

Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz – Description

ISO 13407

Human-Centered Design Processes for Interactive Systems

ISO 6954-2000

Mechanical Vibration-Guidelines for the Measurement, Reporting, and Evaluation of Vibration with regard to Habitability on Passenger and Merchant Ships

JPR 8080.5

JSC Design and Procedural Standards

JSC 63828

Bio-Safety Review Board Operations and Requirements Document

JSC 65993

Commercial Human Systems Integration Requirements

JSC 65994

Commercial Medical Operations Requirements Document

JSC 65995

Commercial Human System Integration Processes

KSC-DE-512

Facility, System, and Equipment General Design Requirements

KSC-NE-9439

KSC Design Engineering Handbook for Design and Development of Ground Systems

NASA-STD-3000 Volume I – II

Man-Systems Integration Standards

NASA-STD-3001 Volume 1

NASA Space Flight Human System Standard Volume 1: Crew Health

NASA-STD-3001 Volume 2

NASA Space Flight Human System Standard Volume 2: Human Factors, Habitability, and Environmental Health

NASA STD 2202-93

Software Formal Inspections Standard

NASA-STD-5002

Load Analyses of Spacecraft and Payloads

NASA-STD-5005

Standard for the Design and Fabrication of Ground Support Equipment (GSE)

NASA/SP-2007-6105

NASA Systems Engineering Handbook

NASA/SP-2008-565

Columbia Crew Survival Investigation Report

NASA/TM-2008-215633

Terrestrial Environment (Climatic) Criteria Guidelines for Use in Aerospace Vehicle Development

NASA TM-2013-217380

Application of the Brinkley Dynamic Response Model to Spacecraft Transient Events

Non-Government Document

Lockheed Engineering and Science, Computer Program Documentation 41-node Transient Metabolic Man Program, Lockheed Engineering and Sciences Company, Inc., 1989.

Non-Government Document

Jakob Nielsen, Usability Engineering, Morgan Kaufmann, Boston, 1993, ISBN 978-0125184069.

Non-Government Document

Stone, R.W., & Letko, W. (1965) “Some observations on the stimulation of the vestibular system of man in a rotating environment,” in NASA SP-77 "The Role of the Vestibular Organs in the Exploration of Space," pp. 263-278.

Procedures for Exchanging Parts, Materials, and Safety Problem Data Utilizing the Government-Industry Data Exchange Program (GIDEP) and NASA Advisories

NWC TP 6575

Parachute Recovery System Design Manual

SAE ARP 5416

Aircraft Lightning Test Methods

SSP 30575

Space Station Interior and Exterior Operational Location Coding System

SSP 41000

System Specifications for the ISS

SSP 50200

Station Program Implementation Plan Volume 9

SSP 50260

ISS Medical Operations Requirement Document

SSP 50505

Basic Provisions on Crew Actions in Case of Fire on the ISS

SSP 50506

Basic Guidelines for Crew Activities During ISS Depressurization

SSP 50653-1

Basic Provisions on Crew Actions in the Event of a Toxic Release on ISS

SSP 57000

Pressurized Payload Interface Requirements Document

The CTS shall be capable of at least two crewed launches to the ISS per year. [R.CTS.001] [I] Rationale: A normal ISS increment is 180 days, requiring a new replacement crew to be launched approximately two times per year.

3.1.1.2 Simultaneous Operation of Spacecraft

The CTS shall simultaneously operate two spacecraft, to allow an ISS NASA crew handover. [R.CTS.002] [I] Rationale: The launch of the next rotation mission may occur prior to the departure of the current increment crew working on the ISS, resulting in a direct crew handover period where two commercial spacecraft would be docked to the ISS for approximately 7 to 10 days. The communication infrastructure in the spacecraft, CVCC, network, and other required assets must be sized to accommodate two operational spacecraft (one docked and one in free-flight mode or both docked).

3.1.1.3 ISS Operations Impacts

The CTS shall not impact ISS operations due to real-time commanding, or active monitoring, during ISS docked operations, except for periodic vehicle maintenance as defined in requirement 3.8.3.1. [R.CTS.003] [I] Rationale: ISS crew time is reserved for science and other operations. The spacecraft design should not require commanding, active monitoring, and maintenance during quiescent docked operations to avoid impacts to the ISS crew science productivity. Additionally, this will reduce the overall burden on the ground infrastructure required to support this spacecraft while docked to the ISS. Periodic vehicle maintenance with a maximum crew impact is defined in requirement 3.8.3.1.

3.1.1.4 EVA Operations

The CTS shall complete the mission without requiring an EVA for nominal operations, contingency operations, or to perform maintenance activity. [R.CTS.004] Rationale: EVA will not occur because of the short time in the spacecraft early in the mission when the complexity of preparing for and executing an EVA precludes that activity. EVAs during the docked timeframe impact ISS crew time, consumables, and on-going science activities. Finally, the timeframe at the end of the flight is envisioned to be a short free-flight duration from undocking to landing, which precludes EVA.

3.1.1.5 Provide Supplies

The CTS shall provide all equipment, supplies, and consumables to support all crewmembers during any portion of the mission when the crew will occupy the spacecraft in a hatch-closed configuration. [R.CTS.005] [I] Rationale: Unless specifically noted in requirement 3.1.1.6 or SSP 50808, the CTS must provide all the supplies necessary for space flight to meet the functions described in CCT-REQ-1130.

3.1.1.6 Transport NASA-Provided Supplies

The spacecraft shall accommodate and utilize the NASA-provided supplies for NASA crew to include the following items: Environmental Health Kit, Food and Utensils, Contamination Cleanup Kit, Passive Radiation Area Monitors, Crew Personal Dosimeters, Medical Kit, ISS Medical Accessory Kit (IMAK), Crew Worn-On Items, and ISS Crew Provisions.

a. The spacecraft shall accommodate a total of 85 kg (187 lbs) of NASA-provided supplies.

b. The spacecraft shall provide a total of 0.323 cubic meters (11.4 cubic feet) of NASA-provided supplies stowage volume. [R.CTS.336] [I] Rationale: NASA has determined that certain items, such as food, clothing, personal dosimeters, a medical kit, and an environmental kit, will be provided to the NASA crew since many of these items will be the same product that they will use on their 180 day stay on the ISS. A notional list of NASA-provided supplies for NASA crew with mass and volumes can be found in Appendix J for reference. Some items in the NASA-provided supplies are driven by the operational timelines and contingency days. The base value for food was chosen in accordance with the notional timeline in Appendix P. For mission durations greater than this, additional food would be required. It is easier for the crew to have the same individual item and familiarity and training with the common items (e.g., Medical Kit) during both the free-flight and docked portions of the mission. For these items, the spacecraft must provide the appropriate stowage and interfaces to properly store the equipment prior to use. These items are not cargo or payload and are in addition to the 100 kg of cargo called out in requirement 3.1.3.1.

3.1.1.7 Supplies for Non-NASA Crew

The CTS shall provide habitable consumables, such as food, water, clothing, oxygen, nitrogen, CO2 removal, personal hygiene, and other required consumables, for non-NASA crew during the docked portion of the mission when the non-NASA crewmembers are on the ISS. [R.CTS.006] [I] Rationale: For any mission model that requires additional crew beyond the 4 NASA crew required for the ISS increment, the CTS will be responsible for carrying the required logistics in the spacecraft to support the additional crewmembers during docked timeframe. NASA will not have the ability to pre-position supplies on ISS via another cargo launch vehicle due to the required ISS logistics support via Cargo Resupply Contract (CRS), Progress, and Automated Transfer Vehicle (ATV)/H-II Transfer Vehicle (HTV) vehicles. Thus, the CTS will be responsible for providing food, water, clothing, and other logistics for non-NASA crew. The nitrogen only needs to be provided if any equipment or operation to support the non-NASA crew is venting air overboard as part of its nominal operation.

3.1.1.8 NASA Crew

The CTS shall accommodate 1, 2, 3, and 4 NASA crewmembers during a single mission. [R.CTS.389] [I] Rationale: Four NASA crew are required to be transported and returned to the ISS during a single mission to meet the United States Operations Segment (USOS) demand for crew time based on full utilization of the ISS to perform science and support the ISS National Laboratory Program. All docking and undocking operations are a significant impact to the completion of ISS science, resulting in the determination by the ISS Program that the most efficient crew rotations strategy is to launch and return 4 crewmembers on a single vehicle. Additionally, the CTS must be able to perform the mission with crew complements of 1, 2, 3, or 4 crewmembers in a single launch or landing to provide flexibility in the ISS crew rotation plan.

The CTS shall transport NASA crew to the ISS. [R.CTS.010] [I] Rationale: NASA crew are required to be transported to the ISS to meet the United States Operations Segment (USOS) demand for crew time based on full utilization of the ISS to perform science and support the ISS National Laboratory Program.

3.1.2.2 Return Crew

The CTS shall return NASA crew from the ISS. [R.CTS.011] [I] Rationale: NASA crew are required to be returned from the ISS to meet the United States Operations Segment (USOS) demand for crew time based on full utilization of the ISS to perform science and support the ISS National Laboratory Program.

3.1.2.3 Docked Duration

The spacecraft shall be capable of being docked to the ISS for 210 days to provide an assured crew return capability for 4 NASA crew. [R.CTS.012] [I] Rationale: The ISS requires continuous presence of the spacecraft to support sustained operations. The 210 days provides 30 days of contingency on the nominal 180 day turnaround.

3.1.2.4 Rotation Intervals

The CTS shall be capable of exchanging up to 4 NASA ISS crewmembers every 150 to 210 days. [R.CTS.013] [I] Rationale: The nominal crew rotation will occur at approximately 180 days based on the ISS human research program medical data collection needs. It is possible for this rotation to be altered by one month (earlier or later) in order to accommodate other overall ISS Program requirements or anomaly resolution/response.

3.1.2.5 Launch Sites

The CTS shall launch from a U.S. (or U. S. State Department approved) launch site(s). [R.CTS.014] Rationale: Launching from a designated U.S. (or U.S. State Department approved) launch sites reduces risk by minimizing necessary abort recovery force assets, increasing proximity to U.S. medical facilities, increasing security, and ensuring a prepared launch and emergency landing site, which minimizes unknown hazards and potential security issues.

3.1.2.6 Landing Sites

The CTS shall return the NASA ISS crew to a designated primary landing site for nominal landings. [R.CTS.015] Rationale: Returning to a designated continental U.S. landing site or waters directly extending from the coast reduces risk by minimizing necessary recovery force assets, increasing proximity to U.S. medical facilities, increasing security, and ensuring a prepared landing site free of hazards. Deconditioned crewmembers have impaired musculoskeletal, cardiopulmonary, and neurovestibular capabilities as a result of long duration exposure to the micro-gravity and space environment, resulting in degraded crewmember performance in the post-landing timeframe. Because of the deconditioned state of the crew, special considerations need to be provided for medical and other post-landing care.

3.1.3 Cargo Transportation

This cargo includes any NASA items (ISS maintenance hardware, powered payloads, etc.), but does not include any required items for spacecraft maintenance, food, water, clothing, hygiene or other crew provisions, medical or environmental kits, documentation or other equipment required to operate the spacecraft, etc. These items required for crew sustenance and operations of the spacecraft will be provided by the CTS and will be allocated mass and volume in addition to cargo goals defined below.

3.1.3.1 Accommodate Soft Stowage Cargo

The spacecraft shall accommodate 100 kg (220.5 lbm) of soft stowage cargo in the pressurized volume during a single mission.

a. The spacecraft shall provide a total of 0.227 cubic meters (8 cubic feet) of pressurized volume to accommodate standard soft stowage cargo.

b. The spacecraft shall provide a contiguous volume with the dimensions 0.468 m x 0.556 m x 0.6245 m (18.4 in x 21.9 in x 24.6 in) within the 0.227 cubic meters (8 cubic feet) volume to accommodate time critical cargo.

c. The spacecraft shall provide soft stowage cargo accommodations per requirements in SSP 50833, ISS Cargo Transport Requirements Document, Section 3.1.2, except for Triple CTB's in section 3.1.2.1 and all M-Bags in section 3.1.2.2. [R.CTS.016] [I] Rationale: The 100 kg, 0.227 cubic meter cargo requirement is sized to transport a small amount of ISS Program-specified cargo inside the spacecraft to be transferred to the ISS upon arrival. The cargo will be contained in either a standard set of ISS soft stowage cargo to easily accommodate transfer by the crew onorbit.