GB/T 29084-2026Grounding requirements for spacecraft (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part

1.Structure and Drafting Rules of Standardization Documents". Drafting. This document replaces GB/T 29084-2012 "Spacecraft Grounding Requirements". Compared with GB/T 29084-2012, except for structural adjustments and rewriting... Aside from the logical changes, the main technical changes are as follows:

a) The scope has been changed (see Chapter 1, Chapter 1 of the.2012 edition);

b) The terms and definitions for "protective ground," "signal ground," "shell ground," and "structural ground" have been added (see 3.1-3.4);

c) Added requirements for the installation grounding of equipment requiring secondary insulation and for the grounding piles of spacecraft modules or structures (see 4.1);

d) The requirement for the number of overlap points in multilayer insulation components has been changed [see 4.2.1b), 2.2.1b) of the.2012 edition];

e) Added requirements for the insulation installation of equipment requiring high-resistance grounding (see 5.1);

f) Changed the grounding requirements for the primary power bus return line and the primary power supply requirements for all equipment directly connected to the spacecraft's primary power bus. The requirement for isolation between the bus return line and the equipment housing [see 5.2a), 5.2b, and 3.2a) and 3.2b of the.2012 edition];

g) Added grounding design requirements for high-voltage equipment (including electric propulsion power processing units) [see 5.2e)];

h) Modified the input and output isolation of the DC-DC converter and the isolation between the DC-DC converter output loop and the equipment housing. Requirements (see 5.3,

3.3 in the.2012 edition);

i) The grounding requirements for high-frequency equipment, low-frequency equipment, and cable shielding have been changed (see 5.5~5.7, 3.5~ in the.2012 edition). 3.7), the technical requirements have been removed (see

4.1 in the.2012 edition);

j) Increased grounding requirements for multi-module spacecraft and multi-spacecraft assemblies (see Chapter 6);

2 Normative references

This document has no normative references.

4 Spacecraft Equipotential Grounding

4.1 Structural equipotential grounding The structural equipotential grounding requirements are as follows:

a) Spacecraft metal structural components should be interlocked, and the interlocking resistance of all metal parts installed on the metal structural components should preferably be less than 5mOmega;

b) Electrically conductive composite materials (such as carbon fiber) in structural components should overlap with the structural ground, and the overlap resistance should be less than 1kOmega;

c) The carbon fiber plates used for mounting the instrument should overlap each other, and the overlap resistance should not exceed 10mOmega;

d) The outer casing of equipment requiring secondary insulation (such as high-resistance grounding equipment like solar panel substrates, battery packs, and solar panel drive mechanisms) should be... Connect an electrostatic discharge resistor, typically 50kOmega~150kOmega;

e) External equipment should be connected to the spacecraft via a bonding connection, with a bonding resistance not exceeding 10 mOmega;

f) The overlap resistance of the docking surfaces of multi-module spacecraft modules should not exceed 5mOmega;

g) Grounding stakes shall be installed on all spacecraft modules or structures, and each grounding stake shall be a single-point grounding point for each module;

h) Grounding should be achieved through a dedicated grounding wire (multi-strand copper wire or copper wire braided tape), with a total cross-sectional area of not less than

5 Spacecraft equipment grounding

5.1 Grounding of spacecraft structure to spacecraft equipment The equipment casing should be grounded by connecting it to the spacecraft structure via a grounding wire, structural component, or copper foil. The bridging resistance between components should not exceed 10mOmega. This applies to equipment requiring high-resistance grounding (such as solar panel substrates, battery banks, and solar panel drives). High-resistance grounding equipment (such as moving mechanisms) should be installed in an insulated manner, and an electrostatic discharge resistor should be connected to the outer casing.

5.2 Primary power supply grounding The primary power supply grounding requirements for spacecraft are as follows:

a) For all equipment directly connected to the spacecraft's primary power bus, the primary power bus return line should be isolated from the equipment casing. The resistance should be no less than 5MOmega~10MOmega;

b) Grounding of the primary power bus return line (including spacecraft using multiple primary power buses) is generally achieved through a power distribution unit or power control unit. The device is structurally connected to the spacecraft at one end;

c) The cross-sectional area of the grounding wire should not be less than

0.5 mm^2, and the lap resistance between the grounding wire and the grounding stake should not be greater than 10 mOmega;

d) The structure of a spacecraft should not be used as the primary power return line for electrical equipment;

e) The grounding method for the output return line of the electric propulsion power processing unit should be designed in accordance with the characteristics of the thruster. The output return line can be connected via a clamping network. Grounding;

f) High-voltage secondary power supplies should preferably use high-resistance grounding to avoid the secondary ground sharing a common ground within floating ground equipment, and the secondary ground being further grounded through other... The problem of secondary connection between the equipment and the casing.

5.3 Grounding of DC-DC converter The grounding requirements for DC-DC converters directly powered from the primary power bus are as follows:

a) Input and output isolation of the DC-DC converter; the isolation resistance should be no less than 10MOmega.

b) For low-frequency equipment using DC-DC converters, the DC-DC converter output return line should be isolated from the equipment housing, with an isolation resistance value of [value missing]. It should be no less than 10MOmega;

c) For high-frequency equipment using DC-DC converters, the DC-DC converter output return line should be connected to the equipment housing.

5.4 Grounding of pyrotechnic devices The grounding requirements for pyrotechnic devices are as follows:

6 Grounding of multi-module spacecraft and multi-spacecraft combinations

6.1 Primary power supply grounding The primary power supply grounding requirements are as follows:

a) For multi-module spacecraft or multi-spacecraft assemblies, where non-isolated power supply is used between modules (or spacecraft), this should be addressed through design (e.g., by adopting...). A grounding switching circuit is used to ensure that the primary power return line of the spacecraft is grounded at a single point in both combined and stand-alone states. (Grounding diagram shown) As shown in Figure 1;

b) Switches J1 and J2 in Figure 1 should be closed after the compartment (or spacecraft) separates to ensure the primary power return line in single-compartment (or single-spacecraft) mode. Single-point grounding;

c) The current-limiting resistors (R11, R12, R21, R22) in Figure 1 can be selected according to the actual grounding requirements, and the resistance value should not be less than 2MOmega. Figure

1.Schematic diagram of the primary power return line grounding of the multi-spacecraft assembly.

6.2 Visiting aircraft grounding The grounding requirements for visiting aircraft are as follows:

a) After the visiting spacecraft docks with the orbiting spacecraft, the contact resistance between the visiting spacecraft structure and the orbiting spacecraft structure should be small. The current resistance is 1Omega, but if necessary, the requirement can be increased to greater than 0.5Omega.

b) After the visiting spacecraft docks with the on-orbit spacecraft, the power supply lines between the visiting spacecraft and the on-orbit spacecraft should be electrically isolated. The isolation resistance should be no less than 1MOmega or meet the requirements of the specific technical documents;

c) When two spacecraft need to rendezvous and dock in orbit, it should be analyzed whether there is a sudden large current at the moment of docking and its impact on the two spacecraft. The impact of this was mitigated, and a discharge channel was set up between the two spacecraft to suppress the instantaneous high current during docking, as required by the model document.

7.Extravehicular activities and on-orbit maintenance grounding in manned spacecraft

7.1 Spacesuit Grounding The grounding requirements for spacesuits are as follows:

a) When astronauts are in the electric umbilical cord working mode outside the cabin, the spacesuit should be connected to the cabin via an electric umbilical cord;

b) When astronauts are in autonomous power supply mode outside the cabin, the spacesuit should be insulated from the cabin.

7.2 Grounding of mobile electrical equipment for spacecraft Since the command bus is already grounded inside the command equipment, the requirements for electrical equipment moving on track are as follows:

8 Spacecraft grounding to ground test system

8.1 Grounding of the test site The grounding requirements for the test site are as follows:

a) The ground facilities of the spacecraft system shall have a grounding system, a lightning protection system, an equipment fault protection system (protective ground) and a signal ground.

b) The site's signal grounding system should be equipped with multiple safe and reliable signal grounding stakes to meet the grounding needs of multiple spacecraft.

c) The site's equipment fault protection system should be equipped with corresponding grounding piles for grounding ground testing equipment.

d) The main grounding stake of the spacecraft should be connected to the signal grounding stake of the site via a dedicated grounding wire in the final assembly and testing facility; in the same test... If multiple spacecraft are being tested at the site, they should be grounded separately, and each signal grounding stake should be connected to only one spacecraft.

e) The launch site technical area should connect the spacecraft's main grounding stake to the test site's signal grounding stake via a dedicated grounding wire, and establish a grounding connection. The resistance should be less than 1Omega.

8.2 Grounding of Test Equipment The grounding requirements for the test equipment are as follows:

a) The grounding point of the power supply equipment for the spacecraft ground test system should be connected to the protective ground of the test site;

b) The grounding of the test equipment should be isolated from the signal interface of the spacecraft;

c) Electronic systems such as ground power supply, excitation source, measuring instruments, and control equipment should be insulated from the casing. For floating equipment, the casing should be connected to a power source for insulation. Protect the land;

d) The spacecraft ground power supply casing should be insulated from the input and output circuits, and the input and output circuits should be isolated. The output circuit should be isolated from the ground power supply. The control circuit should be isolated, and the isolation resistance should be greater than 1MOmega;

e) The casing of the terrestrial high-frequency equipment is connected to the internal power ground. If wired testing is to be performed, the protective ground and the information ground should be isolated.

9.Spacecraft assembly, testing and storage, transportation, transfer, refueling, hoisting and grounding

9.1 Assembly grounding During spacecraft assembly, the spacecraft's main grounding stake should be connected to the signal grounding stake in the assembly plant via a dedicated grounding wire to establish electrical connection. The resistance should be less than 1Omega.