Attachment 002 - LSIRD TROPICS Pathfinder.pdf

Time-Resolved Observations of Precipitation structure and storm Intensity with a

Constellation of Smallsats – Pathfinder Mission

(TROPICS Pathfinder)

Launch Service Interface Requirements Document (LSIRD)

[Rev 1.0, May 1, 2020]

RFQ 80KSC020Q0011 Attachment 002 LSIRD TROPICS Pathfinder

TABLE OF CONTENTS

1 INTRODUCTION & SCOPE 4

1.1 DOCUMENT PURPOSE 6

1.2 DOCUMENT OBJECTIVES 6

2 DOCUMENTS 6

2.1 APPLICABLE DOCUMENTS 6

2.2 REFERENCE DOCUMENTS 6

3 INTERFACE REQUIREMENTS 7

3.1 MECHANICAL INTERFACES 7

3.1.1 Structural Interfaces 7

3.1.2 Structural Loads 11

3.1.3 Mass Properties 11

3.2 ELECTRICAL INTERFACES 12

3.2.1 Airborne Interfaces 12

3.2.2 Lightning Suppression 15

3.2.3 GSE Interfaces 15

3.3 ENVIRONMENTAL INTERFACES 15

3.3.1 Thermal Interfaces 15

3.3.2 Purge 16

3.3.3 Payload Fairing Internal Pressure 16

3.3.4 Dynamic Environments 16

3.3.5 Electromagnetic Compatibility 18

3.4 MISSION DESIGN 19

3.4.1 Orbit Insertion Requirements 19

3.4.2 Thermal Roll 19

3.4.3 Sun Angle Constraints 19

3.4.4 LV Ascent Duration Requirement 19

3.4.5 Launch Period/Windows 19

3.4.6 S/C Events from T-0 through several minutes after separation 19

3.4.7 Separation Requirements 20

3.4.8 Post Separation Requirements 20

3.4.9 Acquisition Assistance 20

3.5 GROUND PROCESSING REQUIREMENTS 20

3.5.1 SV Ground Handling 20

3.5.2 Spacecraft Hazards 20

1 INTRODUCTION & SCOPE

This Launch Services Interface Requirements Document (LSIRD) defines the electrical, data, and mechanical interfaces between the launch dispenser in which the “Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats” (TROPICS) Pathfinder Space Vehicle (SV) is loaded into and the Launch Vehicle (LV).

National Aeronautics and Space Administration (NASA) has contracted MIT Lincoln Laboratory (MIT LL) to build and operate the TROPICS mission, which will provide rapid-revisit passive microwave measurements over low-latitude tropical regions. These measurements will be used to observe the thermodynamics of the troposphere and precipitation structure for storm systems at the mesoscale and synoptic scale over the entire storm life cycle.

The TROPICS six-cubesat constellation mission was selected by the NASA Earth Venture Instrument-3 program as a Class D mission adhering to tailored 7120.5E requirements. Prior to the fabrication of the six 3U flight units, an engineering qualification unit (“qual unit”) was fabricated and tested extensively (TVAC, thermal cycling, and three-axis random vibration) to validate all design elements. The qual unit was tested to GEVS qualification levels (inside a Planetary Systems Corporation CubeSat Dispenser mounted to Moog Shockwave isolators). The six flight units were then tested to GEVS acceptance levels. Upon successful completion of the testing of these seven units, the design was validated to a very high level of confidence.

The TROPICS Project has chosen to fly the qualification unit (henceforth referred to as the “Pathfinder Unit” or “Pathfinder CubeSat” or simply “Pathfinder”) in advance of the TROPICS constellation mission to permit the checkout and optimization of all mission elements prior to the primary mission. All aspects of the primary mission will be duplicated for the Pathfinder mission, including the same KSAT Lite ground stations, identical BCT missions operations support, and data processing. This approach is expected to result in substantial risk reduction in tbe ground, flight, data, and science segments of the mission. This preparatory “TROPICS Pathfinder Mission” is now in formulation. A relatively wide range of orbital parameters (450-600 km;

inclinations greater than 30 degrees) would satisfy the objectives of the Pathfinder Mission, making it well suited to a rideshare launch. The TROPICS Pathfinder CubeSat will consist of a single radiometer payload hosted on a spacecraft bus containing an Attitude Determination & Control System (ADCS), flight avionics, power, and communications subsystems, as shown in Figure 1. The stowed configuration of the CubeSat is shown in Figure 2.

1.1 DOCUMENT PURPOSE

This document defines the TROPICS Pathfinder to LV interface/integration requirements and constraints necessary to assure technical compatibility and to contribute to mission success.

1.2 DOCUMENT OBJECTIVES

1. To provide a definition of the TROPICS Pathfinder to LV integration and interface requirements as necessary to permit their design and implementation.

2. To identify facility and mission operations support requirements.

2 DOCUMENTS

2.1 APPLICABLE DOCUMENTS

MIL-STD-461F Requirements for the control of Electromagnetic Interference Characteristics of Subsystem and Equipment, 1999-8-20

IEST-STD-CC1246 Product Cleanliness Levels and Contamination Control Program

2.2 REFERENCE DOCUMENTS

ISO 14644-1 Classification for Air Cleanliness

PSC 2002337E Canisterized Satellite Dispenser (CSD) Data Sheet

PSC 3000257B

Canisterized Satellite Dispenser (CSD) Operating and Integration Procedure

SW-150-1000-190-7575 Shockwave Isolator Assembly ICD

3 INTERFACE REQUIREMENTS

This section establishes the launch services (LS) interface design requirements for TROPICS Pathfinder. The TROPICS Pathfinder design is finalized and this section reflects requirements levied on the space vehicle design and identifies launch vehicle and processing interface requirements known to date.

3.1 MECHANICAL INTERFACES

3.1.1 Structural Interfaces

a) The contractor shall deploy a single TROPICS Pathfinder 3U CubeSat from a TROPICS project provided Planetary Systems Corporation 3U CubeSat Dispenser (part number 4000744A) mounted on Moog Shockwave isolators (part number SW-150-1000-190- 75H1) to the –Y face of the PSC CSD, as depicted in Figure 3 and 4.

Figure 3: Launch Dispenser and Isolation System for the TROPICS Pathfinder

Figure 4: TROPICS Pathfinder CubeSat Stowed in the CSD

LV Interface Figure 5 details the isolator bolt locations for mounting to the LV. All dimensions are in mm.

a) The contractor shall provide an interface compatible with the CSD/isolator bolt pattern as shown in Figure 5 for mounting to the LV using #10/32 tapped holes or inserts. A maximum true position tolerance on the LV adapter plate tapped holes is 0.010” (0.25 mm).

b) The contractor shall install the 6 Moog Shockwave isolators onto the interface plate.

c) The contractor shall install the CSD onto the isolators with TROPICS project provided 10/32 x ¾” fasteners. (NAS1351N3-12)

Figure 5: CSD, Isolator, and LV Interface Bolt Pattern

CSD Coordinate System The CSD coordinate system is a right hand Cartesian coordinate system with the origin located as indicated in Figure 6. The +Y-axis is at the intersection between the dispenser backplane and the bottom plane; the +Z-axis points in the direction of the deployment velocity vector of the SV;

and the +X-axis points in the direction given by the right hand coordinate system.

Figure 6: CSD Coordinate System

SV Figures The physical dimensions of the TROPICS Pathfinder CubeSat, loaded into its CSD and mated to its isolation system, are shown in Figure 7. All dimensions in mm. Isolators are mounted on the –Y face of the CSD.

Figure 7: Physical Dimensions of Pathfinder, Loaded into Dispenser, on Isolators

The CSD door is fully open at 91.5 degrees as shown in Figure 8.

Figure 8: Physical Dimensions of Pathfinder, Loaded into Dispenser, on Isolators

SV Access Requirements The TROPICS Pathfinder CubeSat does not require access after integration to the launch vehicle.

3.1.2 Structural Loads

Stiffness (SV Frequency) The TROPICS Pathfinder CubeSat, dispenser, and isolation system will have a first natural frequency greater than 30 Hz.

The primary modes of the SV in the dispenser will be over 100 Hz, and thus not excited by low frequency sinusoidal vibration.

3.1.3 Mass Properties

Mass Table 1 presents the mass properties of the TROPICS Pathfinder, loaded into its CSD and mated to its isolation system. Center of mass values are given in the CSD Coordinate System. Moment of inertia values are given about the center of mass and aligned with the CSD Coordinate System.

Table 1: Mass Properties of Integrated TROPICS SV, CSD, and Isolation System

Symbol Parameter Conditions Units Min Max

V Voltage Provided from Launch Vehicle to Open Door

Power to pins 1 & 2, return from pins 3 &

Vdc 22 34

RDI

Winding Resistance of Door Initiator (3)

-45 to +90 degree C, includes internal CSD wiring ohm 7.4 13

LDI

Inductance of Door Initiator

At terminals mH .452

IP

Peak Current Draw from Door Initiator (4)

<0.005 sec A 1.7 4.9

IC

Continuous Current Draw from Door Initiator (5)

A .10 1.5

T Time to Initiate (Open Door) (5)

-45 to +90 degree C, <10e-5 torr s .010 .050

RS

Switch Terminal Resistance

Door and occupancy switches, closed circuit, includes internal CSD wiring, - 45 to +90 degree C ohm .046 .107

ISR

Current Capacity of Switch, Resistive

28 Vdc, <10e-5 torr, door and occupancy switches

A - 2.5

ISI

Current Capacity of Switch, Inductive

28 Vdc, <10e-5 torr, door and occupancy switches

A - 1.5

PT

Payload Travel Required for Occupancy Switch Change State

+Z travel from launch position in [mm] 13.2 [335]

DP

Door Position for Door Switch Change of State

Angle (0 deg is closed) deg .3 2.0

Figure 9: CSD Electrical Schematic

Figure 10: Launch Vehicle Electrical Interface

Figure 11: Representative Initiation Electrical Profile

3.2.2 Lightning Suppression

TROPICS Precursor does not require lightning suppression.

3.2.3 GSE Interfaces

Electrical Connectors at the EGSE Room/Umbilical Interface N/A

3.3 ENVIRONMENTAL INTERFACES

3.3.1 Thermal Interfaces

Ground Operations Temperature, Humidity, and Contamination Control

a) The contractor shall maintain the temperature, humidity, and air cleanliness values given in Table 4.

b) The contractor shall provide contamination control to meet TROPICS requests per Table 4.

Table 4: Spacecraft Gas/Thermal Conditioning Requirements

The TROPICS Pathfinder will not transmit less than 30 minutes after deployment.

3.4.7 Separation Requirements

The LV upper stage body rates just prior to separation command shall be ±3.0 degrees/sec or less in each axis.

3.4.8 Post Separation Requirements

The LV shall perform a CCAM maneuver to ensure no recontact with the SVs.

3.4.9 Acquisition Assistance

The contractor shall provide NASA LSP and the TROPICS project with an Orbital Parameter Message (OPM) for the LV orbit state at separation event, within 30 minutes of that event.

3.5 GROUND PROCESSING REQUIREMENTS

3.5.1 SV Ground Handling

Facility Requirements (PAD / Launch Site) N/A

Spacecraft Handling during Ground Processing The contractor shall provide the TROPICS project with a maximum of four hours of non-hazardous standalone processing in their cleanroom work area at the launch site integration facility. At the end of this time, the TROPICS Pathfinder integrated dispenser assembly will be ready for integration onto the LV.

3.5.2 Spacecraft Hazards

N/A

Common Acronyms and Abbreviations

ADCS Attitude Determination & Control System C Celsius CCAM Collision and Contamination Avoidance Maneuver CG Center of Gravity CSD Canisterized Satellite Dispenser deg Degree ECS Environmental Control System EGSE Electrical Ground Support Equipment F Fahrenheit ft Foot GEVS General Environmental Verification Standard GN2 Gaseous Nitrogen GSE Ground Support Equipment HEPA High-Efficiency Particulate Air hr Hour Hz Hertz ICD Interface Control Document I/F Interface IFD In-Flight Disconnect in Inch IRD Interface Requirements Document ISO International Standards Organization kbps Kilobits per Second km Kilometer KSC John F. Kennedy Space Center l Liter lb Pound LRD Launch Readiness Date LS Launch Services LSIRD Launch Services Interface Requirements Document LSP Launch Services Program LSTO Launch Services Task Order LV Launch Vehicle LVC NASA Launch Vehicle Contractor m Meter MGSE Mechanical Ground Support Equipment MIT Mission Integration Team MIT LL MIT Lincoln Laboratory MLT Mean Local Time mm millimeter MPE Maximum Predicted Environment NASA National Aeronautics and Space Administration NLS NASA Launch Services NLT No Later Than NRZ-L Non-Return to Zero – Phase L

NTE Not to Exceed NVR Non-Volatile Residue OPM Orbital Parameters Message PAC Percent Area Coverage PAF Payload Attach Fitting PLA Payload Adapter PLF Payload Fairing PSC Planetary Systems Corporation Psia Pounds Per Square Inch Absolute Psig Pounds Per Square Inch Gauge PPF Payload Processing Facility PTC Passive Thermal Control RAAN Right ascension of the ascending node RF Radio Frequency RLSP Request for Launch Services Proposal SV Space Vehicle or Spacecraft SVC Space Vehicle Contractor SCFH Standard Cubic Foot Per Hour SCFM Standard Cubic Foot Per Minute SI Systeme International d'Unites SOW Statement of Work SRS Shock Response Spectrum SSF Spacecraft Structural Frame TML Total Mass Loss TOD True of Date

TROPICS

Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats

VDC Volts – Direct Current