Attachment_B_-_DRFP_PPE_Reqmts_.pdf

Next Space Technologies for Exploration Partnerships -2

(NextSTEP-2)

Omnibus Broad Agency Announcement(BAA)

Appendix C: Power and Propulsion Element (PPE) Studies

NNH16ZCQ001K-PPE

Attachment B

Power and Propulsion Element (PPE)

Level 3 and 4 Requirements

Distribution:

[ ] NASA (U.S. Gov. Only) [ ] Project Only [ X ] Government and Contractors

Availability:

[ X ] Public (No Restriction) [ ] Export Controlled [ ] Confidential/ Commercial [ ] Internal Use Only

1.1 TOP REQUIREMENTS

The following sections contain the mission requirements for the Power and Propulsion Element.

L3-PPE-01 Power and Propulsion Element Lifetime

The Power and Propulsion Element shall have a minimum operational lifetime of 15 years in cis-lunar space.

Rationale: The Power and Propulsion Element lifetime of 15 years initiates when the element is launched. The Power and Propulsion Element lifetime terminates when DSG Disposal orbit insertion is complete.

Children:

L4-PPE-104 Maximum Solar Distance

The PPE shall operate at a maximum solar distance of 1.03 AU (TBR-011).

Rationale: This solar distance does not include LLO. Assumes operation between translunar injection and cislunar orbits.

L4-PPE-101 Disposal

The PPE shall perform disposal of exploration elements at end of operational life per NPR-8715.6B NASA Procedural Requirement for Limiting Orbital Debris and Evaluating Meteoroid and Orbital Debris Environments.

L4-PPE-102 Operational Lifetime

The PPE shall have a minimum operational lifetime of 15 years in cis-lunar space.

L4-PPE-103 Minimum Solar Distance

The PPE shall operate at a minimum solar distance of 0.97 AU (TBR-017).

Rationale: This solar distance does not include LLO. Assumes operation between translunar injection and cislunar orbits.

L3 New: The PPE shall be capable of surviving an eclipse for up to 1.5 hours

(TBR-019).

L3-PPE-02 Power and Propulsion Element Power

The Power and Propulsion Element shall transfer up to 27 kW (TBR) of electrical power to the external hardware throughout its lifetime.

Rationale: The 27 kW electrical power value represents the maximum amount of power transferred to the external hardware other than the Power and Propulsion Element. This limits the available power for SEP thrusting.

L4-PPE-106 Power Transfer During Eclipse

The PPE shall be capable of providing at least 8 kW (TBR-018) of electrical power to Exploration Elements during an eclipse for up to 1.5 hours (TBR-019) duration through end of life.

L4-PPE-105 Power Transfer During Non-Eclipse

The PPE shall be capable of providing at least 27 kW (TBR) of electrical power to Exploration Elements in the absence of eclipse through end of life.

L3-PPE-03 Power and Propulsion Element Propulsion Capability

The Power and Propulsion Element shall provide orbit transfer for all un-crewed configurations of the Exploration Elements with maximum masses and center of masses for the configurations shown in Table 1 (TBD), with the center of masses relative to the coordinate system in Figure 1 (TBD).

Rationale: The capability of the Power and Propulsion Element provides in-space transportation for the external hardware. Reference configuration examples.

L4-PPE-107 Orbit Transfer

The PPE shall provide orbit transfer for all un-crewed configurations of the Exploration Elements with maximum masses and center of masses per Table 1 (TBD), with the center of masses relative to the coordinate system in Figure 1

(TBD).

L3-PPE-04 Power and Propulsion Element Xenon Capacity

The Power and Propulsion Element shall have 2,000 kg-class tank Xenon capacity.

Rationale: The capability of the Power and Propulsion Element to provide in-space transportation to the external hardware is expressed in terms of Xenon load. The 2000 kg class tank capacity is derived from commercial spacecraft.

The PPE tank capacity of 2000kg is imposed to protect the capability for late addition of extra Xenon if SLS Co-manifested payload performance exceeds the 8t limit imposed on the PPE. It is anticipated that a partial load would be nominally launched, but if additional SLS performance is available, additional Xenon could be added in the tank capacity.

L4-PPE-109 Xenon Tank Capacity

The PPE shall have a 2,000 kg-class Xenon capacity.

L3-PPE-05 Power and Propulsion Element Launch Vehicle

The Power and Propulsion Element shall be compatible with the SLS vehicle co-manifested launch on EM2.

Rationale: The Power and Propulsion Element will be subject to the SLS environments documented in the SLS Mission Planners Guide (document reference) and additional constraints associated with launch on EM-2.

As EM-2 is planned to be launched on the first crewed Block 1B SLS launch. Co-manifesting Power and Propulsion Element with Orion on EM-2 will limit its mass more than if it was on later Exploration Missions. Currently this would constrain the Power and Propulsion Element to 7,500 kg total launch mass including the Payload Adapter and any partner provided hardware or systems. As such, the Power and Propulsion Element will be subject to the SLS launch mass constraints associated with an Orion co-manifest launch. The PPE will also be capable of accommodating SLS Block 1B induced environments.

L4-PPE-112 Co-Manifest Payload

The PPE shall launch as a co-manifested payload with Orion.

Rationale: The Power and Propulsion Element will be subject to the SLS environments documented in the SLS Mission Planners Guide (document reference) and additional constraints associated with launch on EM-2.

L4-PPE-111 Launch Volume

The PPE shall launch in the Space Launch System, Upper Stage Adapter (USA).

Rationale: The Power and Propulsion Element will be subject to the SLS environments documented in the SLS Mission Planners Guide (document reference) and additional constraints associated with launch on EM-2.

L3-PPE-06 Power and Propulsion Element Attitude Control

The Power and Propulsion Element shall provide attitude control for all crewed and un-crewed configurations of Exploration Elements with maximum masses and center of masses for the configurations shown in Table 2 (TBD), with the center of masses relative to the coordinate system in Figure 1 (TBD) with the exception of rendezvous and docking when the Power and Propulsion Element is the passive element and will enter a state of free drift.

Rationale: The Power and Propulsion Element will provide attitude control using RCS, momentum wheels, SEP thrust vectoring (TBD-021) for the entire stack. The control authority requirements for attitude control will change over time as exploration elements are added.

L4-PPE-113 Non-propulsive Attitude Control

The PPE shall be capable of providing non-propulsive attitude control for all configurations of Exploration Elements in Table 2 (TBD) up to (TBD-005) rates in each axis.

L4-PPE-114 Propulsive Attitude Control

The PPE shall be capable of providing propulsive attitude control for all configurations of Exploration Elements in Table 2 (TBD) up to (TBD-009) rates in each axis.

L4-PPE-115 Mass and Center of Mass

The PPE shall be capable of providing attitude control for all configurations of Exploration Elements up to stack mass per Table 2 (TBD) and stack center of mass, with the center of mass relative to the coordinate system in Figure 1 (TBD).

L4-PPE-NEW Rendezvous and Docking The PPE shall be capable of entering into a stable free-drift state as the passive element during rendezvous and docking.

L3-PPE-07 Power and Propulsion Element Interfaces The Power and Propulsion Element shall provide two International Docking System Standard compliant interfaces both forward and aft and additional DSG-specified interfaces.

Rationale: The Power and Propulsion Element will be equipped with two International Docking System Standard (IDSS) compliant systems one forward and one aft. The IDSS specification will include interfaces for power, C&DH and fluids as standard interfaces.

L3 New: The Power and Propulsion Element shall provide one storage port interface.

L3 New: The PPE shall provide a single (TBR) passive base interface plate (PBIP) for robot arm operations.

L4 New: The PPE provide a single (TBR) passive base interface plate (PBIP) with power, data, and video interfaces to support robot arm operations.

L3 New: The PPE shall provide a single (TBR) wedge mounting interface (WMI).

L4 New: The PPE shall provide a single (TBR) wedge mounting interface (WMI) with power, data and command interfaces.

L3 New: PPE shall utilize data interfaces of IDSS to connect to software systems on other elements.

Rationale: At minimum, the PPE must interface with a common flight software approach to integrate with the stack.

L4-PPE-116 IDSS Interface

The Power and Propulsion Element shall provide passive docking capability forward and aft through IDSS compliant systems.

L3-PPE-08 Power and Propulsion Element Communication

The Power and Propulsion Element shall provide X-Band, Ka-Band, S-Band and UHF communications.

Rationale: The Power and Propulsion Element will provide communications X-band uplink and downlink and Ka-band downlink with the Ground, and S-band with the external hardware. PPE will support UHF communications with EVA.

L4-PPE-118 X-Band Communication

The PPE shall communicate with the Earth using X-band for uplink and downlink.

L4-PPE-119 Ka-Band Communication

The PPE shall communicate with the Earth using Ka-band for downlink.

L4-PPE-117 S-Band Communication

The PPE shall communicate with visiting vehicles using S-Band.

L4-PPE-120 UHF Communication

The PPE shall provide RF, data, power and mounting interfaces to support communications during EVAs.

L4 New: Nominal un-crewed operations of PPE shall utilize 8 hours of communication coverage per week.

Rationale: Uncrewed phases are intended to minimize ground control for nominal operations. DSN schedule constraints prevent extensive communications coverage during unmanned periods.

L4 New: The PPE shall support contingency operations with up to 3 (TBR) weeks without communication with ground controllers.

L3-PPE-09 Power and Propulsion Element Human Rating

The Power and Propulsion Element shall be an element of the human rated Deep Space Gateway system.

Rationale: Compliance with Certification Requirements for NASA Deep Space Missions HEOMD-XX–1000X (TBR-002). The specific requirements drive aspects of crew safety. This drives hazard controls and interoperability requirements.

The Power and Propulsion Element will be capable of supporting EVA but will not be EVA/EVR maintainable.

L4 New: The PPE shall comply with the DSG allocation of HEOMD-003 Deep Space Exploration Systems Certification Requirements and Standards (TBD).

L3-PPE-010 Power and Propulsion Element Refuelablility

The Power and Propulsion Element shall be on-orbit refuelable both forward and aft.

Rationale: The Power and Propulsion Element will have refuel capability incorporated with/near the forward and aft IDSS compliant interfaces for both xenon and hydrazine.

L4-PPE-128 Hydrazine Refueling

The PPE shall be capable of being refueled up to (TBD-007) kg of hydrazine propellant with an IDSS-compliant Interface

L4-PPE-127 Xenon Refueling

The PPE shall be capable of being refueled up to 2000 kg (TBR-012) of xenon propellant with an IDSS-compliant Interface.

L3-PPE-011 Power and Propulsion Element Extensibility

The Power and Propulsion Element shall demonstrate an advanced integrated 50-kW-class Solar Electric Propulsion system that is extensible to future human Mars-class missions.

Rationale: The advanced solar electric propulsion system employs elements that have solar arrays with a high power-to-mass ratio, stowed volume efficiency, deployed strength and radiation tolerance. , It has high-power electric propulsion with the specific impulse and total impulse needed for future Mars missions.

Addresses Human Exploration and Operations Exploration Objective P1-06 to demonstrate operation of long-duration high power solar arrays and solar electric propulsion (SEP) transportation of in-space propulsion elements.

L4-PPE-129 Xenon Processing Capacity

The PPE shall be capable of processing 5000 kg (TBR-014) of xenon propellant.

Rationale: This is a lifetime requirement for extensibility. This demonstrates lifetime of the EP string.

L4-PPE-131 Solar Array Technology Demonstration

The PPE shall demonstrate solar array technology with the power-to-mass ratio, stowed volume efficiency, deployed strength and radiation tolerance that is extensible for future human missions to Mars at a 300 kW class power level.

L4-PPE-130 High-Power Solar Electric Propulsion (SEP) System

The PPE shall demonstrate inflight performance of an integrated 50 kW-class Solar Electric Propulsion (SEP) System.

L3-PPE-012 Power and Propulsion Element Lunar Orbit

The Power and Propulsion Element shall be capable of inserting into a crew-accessible Near Rectilinear Halo Orbit (NRHO) in no longer than 100 days (TBR-003) after launch.

Rationale: Identification of the NRHO orbit is needed to scope the mission.

L4-PPE-132 Missed Thrust Outage

The PPE shall recover from missed thrust outages.

L4-PPE-135 Transport to NRHO

The PPE shall be capable of inserting from Translunar injection into a Near Rectilinear Halo Orbit (NRHO).

L4-PPE-134 Orbit Insertion Timeframe

The PPE shall be capable of inserting into a Near Rectilinear Halo Orbit (NRHO) within 100 days (TBR-003) after launch vehicle separation.

L3 New: The PPE shall operate in cislunar space after translunar injection.

Rationale: PPE will operate from EUS separation post TLI, through translation to a NRHO and operations in various cislunar orbits. The PPE is not intended for interplanetary transfers or operation in LLO. Applies after insertion phase.

L3-PPE-013 Power and Propulsion Element Capability 2

The Power and Propulsion Element shall provide orbit maintenance for all crewed and un-crewed configurations of the Exploration Elements with maximum masses and center of masses for the configurations shown in Table 2 (TBD), with the center of mass relative to the coordinate system in Figure 1 (TBD).

Rationale: The capability of the Power and Propulsion Element provides in-space transportation for the external hardware.

L4-PPE-108 Orbit Maintenance

The PPE shall provide orbit maintenance for all configurations of the Exploration Elements with maximum masses and center of masses for the configurations shown in Table 2 (TBD), with the center of mass relative to the coordinate system in Figure 1 (TBD).

L3-PPE-014 Power and Propulsion Element Mass

The Power and Propulsion Element shall not exceed a mass of 7500 kg including the payload adapter.

Rationale: 7500 kg includes Payload Adaptor (which includes Payload Interface Adaptor and Payload fitting) but does not include 500kg being held at the management level above the Power and Propulsion Element. Currently this would constrain the Power and Propulsion Element to 7,500 kg total launch mass (wet) including the Payload Adapter and any partner provided hardware or systems.

L4-PPE-110 Launch Mass

The PPE shall have a launch mass of less than or equal to 7500 kg including the Payload Adapter.

Rationale: 7500 kg includes Payload Adaptor (which includes Payload Interface Adaptor and Payload Fitting) but does not include 500kg being held at the management level above the Power and Propulsion Element. Currently this would constrain the Power and Propulsion Element to 7,500 kg total launch mass (wet) including the Payload Adapter and any partner provided hardware or systems.

L3-PPE-015 Power and Propulsion Element Communication 2

The Power and Propulsion Element shall accommodate optical communication demonstration.

Rationale: The Power and Propulsion Element will accommodate an optical communication demonstration by providing attachment to a Passive Base Interface Plate.

L4-PPE-121 Optical Communication

The Power and Propulsion Element shall provide a Passive Base Interface Plate attachment point for accommodation of an optical communication demonstration.

L3-PPE-016 Power and Propulsion Element Translation Path

The Power and Propulsion Element shall provide a translation path for EVA.

Rationale: The translation path refers to a quantifiable translation path for EVA.

PPE to assess if significant driver. DSG to determine EVA needs relating to PPE.

L4-PPE-124 EVA Compatibility

The PPE shall provide a translation corridor for EVAs.

L3-PPE-017 Power and Propulsion Element Xenon Loading

The Power and Propulsion Element shall launch with a minimum of 1200kg (TBR-020) of Xenon.

Rationale: Specifying the tank loading allocates mass for translation capability without refueling.

L4-PPE-136 Xenon Tank Loading

The PPE shall launch with a minimum of 1200kg (TBR-020) of Xenon.