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Space Robotics

Environment References

The documents below are the environment definitions planetary and orbital hardware is designed against. Each is a controlling model or specification rather than a result for any one vehicle.

Design specifications

Section titled “Design specifications”

Cross-Program Design Specification for Natural Environments (DSNE), SLS-SPEC-159. The controlling requirements document for US deep space hardware. It converts environment models into design values: thermal extremes, radiation dose, regolith properties, atmospheric density profiles, and dust loading. If a NASA vehicle is designed against a number for a natural environment, this is usually where the number comes from. Revision G is the current public release; the 2017 revision is retained because much existing hardware was designed against it [1].

Lunar

Section titled “Lunar”

Lunar Sourcebook: A User’s Guide to the Moon is the standard reference on lunar regolith, geology and surface conditions, compiled from Apollo results [2]. Chapter 7 on the physical and mechanical properties of regolith and Chapter 9 on the lunar environment remain the starting point for any surface mobility or mechanism design. It predates the polar volatiles work, so it does not address ice.

Supporting material covers regolith particle geometry from Apollo samples, which underlies abrasion behavior, and dust deposition test methodology for evaluating seal and mechanism wear.

Atmospheric models

Section titled “Atmospheric models”

The Global Reference Atmospheric Model series provides engineering-level atmospheric density, temperature, and wind profiles, including dispersions. These are the models entry, descent, and landing analyses actually run against.

  • Mars-GRAM governs EDL design and Ingenuity’s flight envelope.
  • Venus-GRAM covers the surface conditions constraining lander survival time.
  • Titan-GRAM is the basis for Dragonfly rotorcraft analysis. Titan’s high atmospheric density and low gravity make flight far less power-limited than on Mars.
  • Outer Planet GRAM supports probe entry analysis at the giant planets.

Radiation and debris

Section titled “Radiation and debris”

Badhwar-O’Neill galactic cosmic ray model. The GCR flux model behind shielding mass and radiation-tolerant avionics decisions. Relevant to the tradeoff visible in Ingenuity, which used commercial processors and accepted higher single-event upset rates in exchange for processing capability.

Bumper. The standard micrometeoroid and orbital debris risk analysis tool, used for shielding design on orbital hardware including the ISS manipulators.

References

  1. Roberts, B. C. (2017). SLS-SPEC-159 Cross-Program Design Specification for Natural Environments (DSNE) Revision E . NASA Marshall Space Flight Center. Source
    BibTeX
    @techreport{nasa2017sls,
  title = {SLS-SPEC-159 Cross-Program Design Specification for Natural Environments (DSNE) Revision E},
  author = {Roberts, Barry C.},
  institution = {NASA Marshall Space Flight Center},
  year = {2017},
  url = {https://ntrs.nasa.gov/citations/20170008140},
  abstract = {The DSNE completes environment-related specifications for architecture, system-level, and lower-tier documents by specifying the ranges of environmental conditions that must be accounted for by NASA ESD Programs. To assure clarity and consistency, and to prevent requirements documents from becoming cluttered with extensive amounts of technical material, natural environment specifications have been compiled into this document. The intent is to keep a unified specification for natural environments that each Program calls out for appropriate application. This document defines the natural environments parameter limits (maximum and minimum values, energy spectra, or precise model inputs, assumptions, model options, etc.), for all ESD Programs. These environments are developed by the NASA Marshall Space Flight Center (MSFC) Natural Environments Branch (MSFC organization code: EV44). Many of the parameter limits are based on experience with previous programs, such as the Space Shuttle Program. The parameter limits contain no margin and are meant to be evaluated individually to ensure they are reasonable (i.e., do not apply unrealistic extreme-on-extreme conditions). The natural environments specifications in this document should be accounted for by robust design of the flight vehicle and support systems. However, it is understood that in some cases the Programs will find it more effective to account for portions of the environment ranges by operational mitigation or acceptance of risk in accordance with an appropriate program risk management plan and/or hazard analysis process. The DSNE is not intended as a definition of operational models or operational constraints, nor is it adequate, alone, for ground facilities which may have additional requirements (for example, building codes and local environmental constraints). "Natural environments," as the term is used here, refers to the environments that are not the result of intended human activity or intervention. It consists of a variety of external environmental factors (most of natural origin and a few of human origin) which impose restrictions or otherwise impact the development or operation of flight vehicles and destination surface systems.}
}
  2. Heiken, G. H., Vaniman, D. T. and French, B. M. (1991). Lunar Sourcebook: A User's Guide to the Moon . Endeavour. Source
    BibTeX
    @book{heiken1991lunar,
  title = {Lunar Sourcebook: A User's Guide to the Moon},
  author = {Heiken, Grant H. and Vaniman, David T. and French, Bevan M.},
  journal = {Endeavour},
  volume = {16},
  pages = {96},
  publisher = {Cambridge University Press},
  year = {1991},
  doi = {10.1016/0160-9327(92)90014-g}
}