Here’s a quick guide to NASA’s payload classification: what is a payload, how NASA classifies them, and what are payload project categorizations.

What is a Payload?

A payload is the spacecraft bus and related instruments found in the payload fairing of a launch vehicle. In other words, a payload is what a launch vehicle carries into space.

Payloads include (but not limited to): space telescopes, satellites, Space Station Modules, landers, rovers, etc. For example, the first test launch of SpaceX’s Falcon Heavy was carrying a Tesla car as payload.

Space Shuttle Discovery (STS-31) carrying the Hubble Space Telescope as payload
April 24, 1990: Space Shuttle Discovery (STS-31) carrying the Hubble Space Telescope as payload. This is a cropped image. You can see the full-size image at ESA/Hubble (SpaceTelescope.org)

Special Case Payload

A NASA special case payload is a payload flying on a vehicle procured outside of the Launch Services Program (LSP) or any payload ride-sharing with another payload.

NASA’s Launch Service Program, or LSP, is responsible for launching uncrewed rockets delivering spacecraft that observe the Earth, visit other planets, and explore the universe, ranging from weather satellites and space telescopes to Mars Rovers.

Examples include:

  • Foreign launch vehicle
  • USAF-procured launch vehicle (United States Air Force)
  • Commercial procured launch vehicle
  • Secondary, auxiliary, or hosted payloads

Payload Classifications

NPR 8705.4, Risk Classification for NASA Payloads

Class A

  • Priority (Criticality to Agency Strategic Plan): High
  • National Significance: Very high
  • Complexity: Very high to high
  • Mission Lifetime (Primary Baseline Mission): Long, more than 5 years
  • Cost: High
  • Launch Constraints: Critical
  • In-Flight Maintenance: N/A
  • Alternative Research Opportunities or Reflight Opportunities: No alternate re-flight opportunities
  • Examples: Cassini, James Webb Space Telescope (JWST, see notes 1)

Class B

  • Priority (Criticality to Agency Strategic Plan): High
  • National Significance: High
  • Complexity: High to medium
  • Mission Lifetime (Primary Baseline Mission): Medium, 2 – 5 years
  • Cost: High to medium
  • Launch Constraints: Medium
  • In-Flight Maintenance: Not feasible or difficult
  • Alternative Research Opportunities or Reflight Opportunities: Few or no alternative re-flight opportunities
  • Examples: Mars Reconnaissance Orbiter (MRO, see notes 2), Mars Science Laboratory (MSL, or commonly known as the Curiosity Rover)

Class C

  • Priority (Criticality to Agency Strategic Plan): Medium
  • National Significance: Medium
  • Complexity: Medium to low
  • Mission Lifetime (Primary Baseline Mission): Short, less than 2 years
  • Cost: Medium to low
  • Launch Constraints: Few
  • In-Flight Maintenance: Maybe feasible
  • Alternative Research Opportunities or Reflight Opportunities: Some or few alternative or re-flight opportunities
  • Examples: Glory (a satellite which is a part of NASA’s Earth Observing System)

Class D

  • Priority (Criticality to Agency Strategic Plan): Low
  • National Significance: Medium to low
  • Complexity: Medium to low
  • Mission Lifetime (Primary Baseline Mission): Short, less than 2 years
  • Cost: Low
  • Launch Constraints: Few to none
  • In-Flight Maintenance: Maybe feasible and planned
  • Alternative Research Opportunities or Reflight Opportunities: Significant alternative or re-flight opportunities
  • Examples: Cyclone Global Navigation Satellite System (CYGNSS) – a space-based system developed by the University of Michigan and Southwest Research Institute with the aim of improving hurricane forecasting by better understanding the interactions between the sea and the air near the core of a storm.
NASA payload classifications
NASA payload classifications

Payload Project Categorization (NPR 7120.5)

High priority

  • LCC (Life Cycle Cost) < $250M: Category 2
  • $250M < LCC < $1B: Category 2
  • LCC > $1B (significant radioactive material or human spaceflight): Category 1

Medium priority

  • LCC (Life Cycle Cost) < $250M: Category 3
  • $250M < LCC < $1B: Category 2
  • LCC > $1B (significant radioactive material or human spaceflight): Category 1

Low priority

  • LCC (Life Cycle Cost) < $250M: Category 3
  • $250M < LCC < $1B: Category 2
  • LCC > $1B , ignificant radioactive material, or human spaceflight: Category 1
NASA payload project categorization
NASA payload project categorization

Notes

1. James Webb Space Telescope (JWST)

Launch payloads: James Webb Space Telescope under construction
James Webb Space Telescope (JSWT) under construction. Image: NASA

The James Webb Space Telescope (JWST) is planned to succeed the Hubble Space Telescope as NASA’s flagship astrophysics mission. It will provide improved infrared resolution and sensitivity over the Hubble Space Telescope and will enable a broad range of investigations across the fields of astronomy and cosmology, including observing some of the most distant events and objects in the universe, such as the formation of the first galaxies.

The primary mirror of the JWST, the Optical Telescope Element, is composed of eighteen 1.32 meters (4 ft 4 in) hexagonal mirror segments made of gold-plated beryllium which combine to create a 6.5 meters (21 ft) diameter mirror – considerably larger than Hubble’s 2.4 meters (7 ft 10 in) mirror.

JSWT is named after James E. Webb (October 7, 1906 – March 27, 1992), the American government official who served as the second appointed administrator of NASA from February 14, 1961, to October 7, 1968.

Webb oversaw all the critical first crewed launches in the Mercury through Gemini programs, until just before the first crewed Apollo flight.

He also dealt with the Apollo 1 fire which occurred during a launch rehearsal test at Cape Kennedy Air Force Station Launch Complex 34 on January 27, 1967. The fire killed all three crew members, Command Pilot Virgil I. “Gus” Grissom, Senior Pilot Ed White, and Pilot Roger B. Chaffee, and destroyed the command module (CM). The name Apollo 1, chosen by the crew, was made official by NASA in their honor after the fire.

2. Mars Reconnaissance Orbiter

Launched on August 12, 2005, aboard an Atlas V rocket, and reached Mars on March 10, 2006, the Mars Reconnaissance Orbiter (MRO) designed to study the geology and climate of Mars from orbit. It also provides reconnaissance of future landing sites, and relay data from surface missions back to Earth.

Equipped with a powerful camera called HiRISE that has aided in a number of discoveries, the Mars Reconnaissance Orbiter has sent back thousands of stunning images of the Martian surface that are helping scientists learn more about Mars, including the history of the water flows on or near the planet’s surface.

Scientific Instrument(s)

  • High-Resolution Imaging Science Experiment (HiRISE)
  • Compact Reconnaissance Imaging Spectrometer for Mars (CRISM)
  • Mars Color Imager (MARCI)
  • Context Imager (CTX)
  • Shallow Radar (SHARAD)
  • Mars Climate Sounder (MCS)
  • Accelerometers

MRO orbits Mars in a near-polar orbit. Its orbital altitude ranges from 255 kilometers (158 miles) to 320 kilometers (199 miles) – highly elliptical.

Mars Reconnaissance Orbiter
Artist’s concept of the Mars Reconnaissance Orbiter in orbit around Mars. Image: NASA

Sources

M. Özgür Nevres
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