Data Description

This page summarizes information about the selected resource and its origin based on SPASE metadata.

Table of Contents

  1. Product
  2. Repository
  3. Instrument
  4. Observatory
  5. Persons

SPASE version 2.0.0

Numerical Data Product: Voyager-2 CRS Cruise Mode 6-hour averages

Resource ID
spase://VEPO/NumericalData/Voyager2/CRS/FLUX/PT6H Get XML
Name
Voyager-2 CRS Cruise Mode 6-hour averages
Description

6-hour averages of selected fluxes

Additional information
http://voyager.gsfc.nasa.gov
http://nssdcftp.gsfc.nasa.gov/spacecraft_data/voyager/voyager2/particle/crs/six_hour/vy2crs_6h_fmt.txt
Acknowledgement

Please acknowledge the Voyager CRS team

Contact
Role Person
1. CoInvestigator Dr. Nand Lal Get XML
Release date
2008-12-05 21:52:14
Repository
Name
NSSDC Get XML
Availability
Online
Access rights
Open
URL
http://nssdcftp.gsfc.nasa.gov/spacecraft_data/voyager/voyager2/particle/crs/six_hour
Format
Text
Instrument
Cosmic Ray System (CRS) Get XML
Measurement type
Energetic particles
Temporal description
Start date
1977-08-22 00:00:00
Stop date
2007-01-01 00:00:00
Cadence
6 hours
Observed regions
Heliosphere.Inner
Heliosphere.NearEarth
Heliosphere.Outer
↑

Parameters

Parameter #1

Name
Time
Description

ISO 8601 formatted UT of start of 6 hour interval

Valid minimum
1977-08-22T00:00:00
Valid maximum
2007-01-01T00:00:00
Fill value
-1.0E31
Parameter type
Temporal

Parameter #2

Name
4.2 - 6 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX1
Description

Helium4 flux derived from A-stopping 2 dimensional analysis, high gain data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
4.2
High energy
6.0
Units
MeV/nucleon

Parameter #3

Name
6 - 42 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX2
Description

Helium4 flux derived from A-stopping 3 dimensional analysis, high gain data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
6.0
High energy
42.0
Units
MeV/nucleon

Parameter #4

Name
17 - 27 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX3
Description

Helium4 flux derived from B-stopping 2 dimensional analysis, low gain data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
17.0
High energy
27.0
Units
MeV/nucleon

Parameter #5

Name
30 - 69 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX4
Description

Helium4 flux derived from B-stopping 3 dimensional analysis, low gain data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
30.0
High energy
69.0
Units
MeV/nucleon

Parameter #6

Name
17 - 27 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX5
Description

Helium4 flux derived from B-stopping 2 dimensional analysis, high gain data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
17.0
High energy
27.0
Units
MeV/nucleon

Parameter #7

Name
30 - 69 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX6
Description

Helium4 flux derived from B-stopping 3 dimensional analysis, high gain data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
30.0
High energy
69.0
Units
MeV/nucleon

Parameter #8

Name
193 - 480 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX7
Description

Helium4 flux derived from low gain penetrating mode data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
193
High energy
480
Units
MeV/nucleon

Parameter #9

Name
191 - 475 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX8
Description

Helium4 flux derived from high gain penetrating mode data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
191
High energy
475
Units
MeV/nucleon

Parameter #10

Name
4.2 - 6 MeV Proton Flux
Parameter key
PROTONFLUX1
Description

Proton flux derived from A-stopping 2 dimensional analysis, high gain data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
4.2
High energy
6.0
Units
MeV

Parameter #11

Name
6 - 42 MeV Proton Flux
Parameter key
PROTONFLUX2
Description

Proton flux derived from A-stopping 3 dimensional analysis, high gain data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
6.0
High energy
42.0
Units
MeV

Parameter #12

Name
17 - 27 MeV Proton Flux
Parameter key
PROTONFLUX3
Description

Proton flux derived from B-stopping 2 dimensional analysis, high gain data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
17.0
High energy
27.0
Units
MeV

Parameter #13

Name
30 - 69 MeV Proton Flux
Parameter key
PROTONFLUX4
Description

Proton flux derived from B-stopping 3 dimensional analysis, high gain data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
30.0
High energy
69.0
Units
MeV

Parameter #14

Name
133 - 242 MeV Proton Flux
Parameter key
PROTONFLUX5
Description

Proton flux derived from high gain penetrating mode data from HET-I

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
132.8
High energy
242
Units
MeV

Parameter #15

Name
4.2 - 6 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX9
Description

Helium4 flux derived from A-stopping 2 dimensional analysis, high gain data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
4.2
High energy
6.0
Units
MeV/nucleon

Parameter #16

Name
6 - 42 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX10
Description

Helium4 flux derived from A-stopping 3 dimensional analysis, high gain data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
6.0
High energy
42.0
Units
MeV/nucleon

Parameter #17

Name
17 - 27 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX11
Description

Helium4 flux derived from B-stopping 2 dimensional analysis, low gain data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
17.0
High energy
27.0
Units
MeV/nucleon

Parameter #18

Name
30 - 69 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX12
Description

Helium4 flux derived from B-stopping 3 dimensional analysis, low gain data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
30.0
High energy
69.0
Units
MeV/nucleon

Parameter #19

Name
17 - 27 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX13
Description

Helium4 flux derived from B-stopping 2 dimensional analysis, high gain data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
17.0
High energy
27.0
Units
MeV/nucleon

Parameter #20

Name
30 - 69 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX14
Description

Helium4 flux derived from B-stopping 3 dimensional analysis, high gain data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
30.0
High energy
69.0
Units
MeV/nucleon

Parameter #21

Name
193 - 480 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX15
Description

Helium4 flux derived from low gain penetrating mode data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
193
High energy
480
Units
MeV/nucleon

Parameter #22

Name
191 - 475 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX16
Description

Helium4 flux derived from high gain penetrating mode data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
191
High energy
475
Units
MeV/nucleon

Parameter #23

Name
4.2 - 6 MeV Proton Flux
Parameter key
PROTONFLUX6
Description

Proton flux derived from A-stopping 2 dimensional analysis, high gain data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
4.2
High energy
6.0
Units
MeV

Parameter #24

Name
6 - 42 MeV Proton Flux
Parameter key
PROTONFLUX7
Description

Proton flux derived from A-stopping 3 dimensional analysis, high gain data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
6.0
High energy
42.0
Units
MeV

Parameter #25

Name
17 - 27 MeV Proton Flux
Parameter key
PROTONFLUX8
Description

Proton flux derived from B-stopping 2 dimensional analysis, high gain data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
17.0
High energy
27.0
Units
MeV

Parameter #26

Name
30 - 69 MeV Proton Flux
Parameter key
PROTONFLUX9
Description

Proton flux derived from B-stopping 3 dimensional analysis, high gain data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
30.0
High energy
69.0
Units
MeV

Parameter #27

Name
133 - 242 MeV Proton Flux
Parameter key
PROTONFLUX10
Description

Proton flux derived from high gain penetrating mode data from HET-II

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
132.8
High energy
242
Units
MeV

Parameter #28

Name
1.8 - 3.3 MeV Proton Flux
Parameter key
PROTONFLUX11
Description

Proton flux derived from 2 dimensional LET-A data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
1.8
High energy
3.3
Units
MeV

Parameter #29

Name
1.8 - 3.3 MeV Proton Flux
Parameter key
PROTONFLUX12
Description

Proton flux derived from 2 dimensional LET-B data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
1.8
High energy
3.3
Units
MeV

Parameter #30

Name
1.8 - 3.3 MeV Proton Flux
Parameter key
PROTONFLUX13
Description

Proton flux derived from 2 dimensional LET-C data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
1.8
High energy
3.3
Units
MeV

Parameter #31

Name
1.8 - 3.3 MeV Proton Flux
Parameter key
PROTONFLUX14
Description

Proton flux derived from 2 dimensional LET-D data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
1.8
High energy
3.3
Units
MeV

Parameter #32

Name
3.3 - 8.1 MeV Proton Flux
Parameter key
PROTONFLUX15
Description

Proton flux derived from 3 dimensional LET-A data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
3.3
High energy
8.1
Units
MeV

Parameter #33

Name
3.3 - 8.1 MeV Proton Flux
Parameter key
PROTONFLUX16
Description

Proton flux derived from 3 dimensional LET-B data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
3.3
High energy
8.1
Units
MeV

Parameter #34

Name
3.3 - 8.1 MeV Proton Flux
Parameter key
PROTONFLUX17
Description

Proton flux derived from 3 dimensional LET-C data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
3.3
High energy
8.1
Units
MeV

Parameter #35

Name
3.3 - 8.1 MeV Proton Flux
Parameter key
PROTONFLUX18
Description

Proton flux derived from 3 dimensional LET-D data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
Proton
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
3.3
High energy
8.1
Units
MeV

Parameter #36

Name
1.8 - 2.8 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX17
Description

Helium4 flux derived from 2 dimensional LET-D data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
1.8
High energy
2.8
Units
MeV/nucleon

Parameter #37

Name
1.8 - 2.8 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX18
Description

Helium4 flux derived from 2 dimensional LET-D data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
1.8
High energy
2.8
Units
MeV/nucleon

Parameter #38

Name
1.8 - 2.8 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX19
Description

Helium4 flux derived from 2 dimensional LET-D data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
1.8
High energy
2.8
Units
MeV/nucleon

Parameter #39

Name
1.8 - 2.8 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX20
Description

Helium4 flux derived from 2 dimensional LET-D data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
1.8
High energy
2.8
Units
MeV/nucleon

Parameter #40

Name
2.8 - 8.0 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX21
Description

Helium4 flux derived from 3 dimensional LET-A data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
2.8
High energy
8.0
Units
MeV/nucleon

Parameter #41

Name
2.8 - 8.0 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX22
Description

Helium4 flux derived from 3 dimensional LET-B data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
2.8
High energy
8.0
Units
MeV/nucleon

Parameter #42

Name
2.8 - 8.0 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX23
Description

Helium4 flux derived from 3 dimensional LET-C data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
2.8
High energy
8.0
Units
MeV/nucleon

Parameter #43

Name
2.8 - 8.0 MeV/nucleon Helium Flux
Parameter key
HELIUMFLUX24
Description

Helium4 flux derived from 3 dimensional LET-D data

Units
1/(cm^2 s sr MeV)
Structure
Size
2
Elements
Index Name Valid min
0 value 0
1 statistical uncertainty in value 0
Particle type
AlphaParticle
Quantity
Number flux
Qualifier
Differential
Energy range
Low energy
2.8
High energy
8.0
Units
MeV/nucleon
↑

SPASE version 2.0.0

Instrument: Cosmic Ray System (CRS)

Instrument ID
spase://SMWG/Instrument/Voyager2/CRS Get XML
Name
Cosmic Ray System (CRS)
Alternate name
CRS
Description

This investigation studied the origin and acceleration process, life history, and dynamic contribution of interstellar cosmic rays, the nucleosynthesis of elements in cosmic-ray sources, the behavior of cosmic rays in the interplanetary medium, and the trapped planetary energetic particle environment. The instrumentation included a High-Energy Telescope System (HETS) and a Low-Energy Telescope System (LETS). The HETS covered an energy range between 6 and 500 MeV/nucleon for nuclei ranging in atomic numbers from 1 through 30. In addition, electrons in the energy range between 3 and 100 MeV were measured by this telescope and an electron telescope. The LETS measured the energy and determined the identity of nuclei for energies between .15 and 30 MeV/nucleon and atomic numbers from 1 to 30. The instruments also measured the anisotropies of electrons and nuclei. In addition, electrons in the energy range between 3 and 100 MeV were measured by the electron telescope.

Additional information
NSSDC's Master Catalog

Information about the Cosmic Ray System (CRS) experiment on the Voyager 2 mission.

Contact
Role Person
1. Principal investigator Prof. Edward C. Stone, Jr. Get XML
Release date
2009-05-20 21:10:14
Instrument type
Energetic Particle Instrument
Investigation name
Cosmic Ray System (CRS) on Voyager 2
Observatory
Voyager 2 Get XML
↑

SPASE version 2.0.0

Observatory: Voyager 2

Observatory ID
spase://SMWG/Observatory/Voyager2 Get XML
Name
Voyager 2
Alternate name
1977-076A
Mariner Jupiter/Saturn B
Description

Voyager 2 was one of a pair of spacecraft launched to explore the planets of the outer solar system and the interplanetary environment. Each Voyager had as its major objectives at each planet to: (1) investigate the circulation, dynamics, structure, and composition of the planet's atmosphere; (2) characterize the morphology, geology, and physical state of the satellites of the planet; (3) provide improved values for the mass, size, and shape of the planet, its satellites, and any rings; and, (4) determine the magnetic field structure and characterize the composition and distribution of energetic trapped particles and plasma therein.

Spacecraft and Subsystems

Each Voyager consisted of a decahedral bus, 47 cm in height and 1.78 m across from flat to flat. A 3.66 m diameter parabolic high-gain antenna was mounted on top of the bus. The major portion of the science instruments were mounted on a science boom extending out some 2.5 m from the spacecraft. At the end of the science boom was a steerable scan platform on which were mounted the imaging and spectroscopic remote sensing instruments. Also mounted at various distances along the science boom were the plasma and charged particle detectors. The magnetometers were located along a separate boom extending 13 m on the side opposite the science boom. A third boom, extending down and away from the science instruments, held the spacecraft's radioisotope thermoelectric generators (RTGs). Two 10 m whip antennas (used for the plasma wave and planetary radio astronomy investigations) also extended from the spacecraft, each perpendicular to the other. The spacecraft was three-axis spin stabilized to enable long integration times and selective viewing for the instruments mounted on the scan platform.

Power was provided to the spacecraft systems and instruments through the use of three radioisotope thermoelectric generators. The RTGs were assembled in tandem on a deployable boom hinged on an outrigger arrangement of struts attached to the basic structure. Each RTG unit, contained in a beryllium outer case, was 40.6 cm in diameter, 50.8 cm in length, and weighed 39 kg. The RTGs used a radioactive source (Plutonium-238 in the form of plutonium oxide, or PuO2, in this case) which, as it decayed, gave off heat. A bi-metallic thermoelectric device was used to convert the heat to electric power for the spacecraft. The total output of RTGs slowly decreases with time as the radioactive material is expended. Therefore, although the initial output of the RTGs on Voyager was approximately 470 W of 30 V DC power at launch, it had fallen off to approximately 335 W by the beginning of 1997 (about 19.5 years post-launch). As power continues to decrease, power loads on the spacecraft must also decrease. Current estimates (1998) are that increasingly limited instrument operations can be carried out at least until 2020.

Communications were provided through the high-gain antenna with a low-gain antenna for backup. The high-gain antenna supported both X-band and S-band downlink telemetry. Voyager was the first spacecraft to utilize X-band as the primary telemetry link frequency. Data could be stored for later transmission to Earth through the use of an on-board digital tape recorder.

Voyager, because of its distance from Earth and the resulting time-lag for commanding, was designed to operate in a highly-autonomous manner. In order to do this and carry out the complex sequences of spacecraft motions and instrument operations, three interconnected on-board computers were utilized. The Computer Command Subsystem (CCS) was responsible for storing commanding for the other two computers and issuing the commands at set times. The Attitude and Articulation Control Subsystem (AACS) was responsible for controlling spacecraft attitude and motions of the scan platform. The Flight Data Subsystem (FDS) controlled the instruments, including changes in configuration (state) or telemetry rates. All three computers had redundant components to ensure continued operations. The AACS included redundant star trackers and Sun sensors as well.

Message in a Bottle

Each Voyager has mounted to one of the sides of the bus a 12-inch gold-plated copper disk. The disk has recorded on it sounds and images of Earth designed to portray the diversity of life and culture on the planet. Each disk is encased in a protective aluminum jacket along with a cartridge and a needle. Instructions explaining from where the spacecraft originated and how to play the disk are engraved onto the jacket. Electroplated onto a 2 cm area on the cover is also an ultra-pure source of uranium-238 (with a radioactivity of about 0.26 nanocuries and a half-life of 4.51 billion years), allowing the determination of the elapsed time since launch by measuring the amount of daughter elements to remaining U238. The 115 images on the disk were encoded in analog form. The sound selections (including greetings in 55 languages, 35 sounds, natural and man-made, and portions of 27 musical pieces) are designed for playback at 1000 rpm. The Voyagers were not the first spacecraft designed with such messages to the future. Pioneers 10 and 11, LAGEOS, and the Apollo landers also included plaques with a similar intent, though not quite so ambitious.

Mission Profile

Originally planned as a Grand Tour of the outer planets, including dual launches to Jupiter, Saturn, and Pluto in 1976-77 and dual launches to Jupiter, Uranus, and Neptune in 1979, budgetary constraints caused a dramatic rescoping of the project to two spacecraft, each of which would go to only Jupiter and Saturn. The new mission was called Mariner Jupiter/Saturn, or MJS. It was subsequently renamed Voyager about six months prior to launch. The rescoped mission was estimated to cost $250 million (through the end of Saturn operations), only a third of what the Grand Tour design would have cost.

Voyager 2 was the first of the two spacecraft to be launched, with liftoff occurring 20 Aug. 1977. What was at first an auspicious launch, however, proved to be the beginning of a number of problems. The primary cause of the initial problems were attributed to commanding by the AACS, including difficulty in determining the full deployment of the science boom. These problems resulted in a delay of four days in the launch of Voyager 1 to ensure they wouldn't occur for it.

Although launched sixteen days after Voyager 2, Voyager 1's trajectory was the quicker one to Jupiter. On 15 Dec. 1977, while both spacecraft were in the asteroid belt, Voyager 1 surpassed Voyager 2's distance from the Sun.

Several months after launch, in April 1978, Voyager 2's primary radio receiver failed, automatically kicking in the backup receiver which proved to be faulty. Attempts to recover the use of the primary receiver failed and the backup receiver was used for the remainder of the mission. Although use of the backup receiver made communication with the spacecraft more difficult, engineers were able to find workarounds.

Voyager 2 proceeded with its primary mission and flew by Jupiter (closest approach on 09 July 1979) and Saturn (05 Aug. 1981). During these flybys, Voyager 2 obtained images roughly equal in number to Voyager 1 (18,000 at Jupiter, 16,000 at Saturn).

Voyager 2's launch date had preserved one part of the original Grand Tour design, i.e. the possibility of an extended mission to Uranus and Neptune. Despite the difficulties encountered, scientists and engineers had been able to make Voyager enormously successful. As a result, approval was granted to extend the mission, first to Uranus, then to Neptune and later to continue observations well past Neptune. Voyager 2 made successful flybys of Uranus (24 Jan. 1986) and Neptune (25 Aug. 1989). Because of the additional distance of these two planets, adaptations had to made to accomodate the lower light levels and decreased communications. Voyager 2 was successfully able to obtain about 8,000 images of Uranus and its satellites. Additional improvements in the on-board software and use of image compression techniques allowed about 10,000 images of Neptune and its satellites to be taken.

All of the experiments on Voyager 2 have produced useful data.

Onward and Outward

Rechristened the Voyager Interstellar Mission (VIM) by NASA in 1989 after its encounter with Neptune, Voyager 2 continues operations, taking measurements of the interplanetary magnetic field, plasma, and charged particle environment while searching for the heliopause (the distance at which the solar wind becomes subsumed by the more general interstellar wind). Through the end of the Neptune phase of the Voyager project, a total of $875 million had been expended for the construction, launch, and operations of both Voyager spacecraft. An additional $30 million was allocated for the first two years of VIM.

Voyager 2 is speeding away from the Sun at a velocity of about 3.13 AU/year toward a point in the sky of RA=338 degrees, Dec=-62 degrees (-47.46 degrees ecliptic latitude, 310.89 degrees ecliptic longitude).

Additional information
NSSDC's Master Catalog

Information about the Voyager 2 mission

Contact
Role Person
1. Project scientist Prof. Edward C. Stone, Jr. Get XML
Release date
2009-05-20 20:00:12
Observatory group
VOYAGER
Location
Region
Heliosphere.NearEarth
Heliosphere.Outer
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SPASE version 2.0.0

Person: Dr. Nand Lal

Name
Dr. Nand Lal
Organization
GSFC-Code 612.4
Person ID
spase://SMWG/Person/Nand.Lal Get XML
↑

SPASE version 2.0.0

Person: Dr. Edwin J. Grayzeck, Jr.

Name
Dr. Edwin J. Grayzeck, Jr.
Organization
GSFC-Code 690.1
Person ID
spase://SMWG/Person/Edwin.J.Grayzeck.Jr Get XML
↑

SPASE version 2.0.0

Person: Dr. Edwin V. Bell, II

Name
Dr. Edwin V. Bell, II
Organization
GSFC-Code 690.1
Person ID
spase://SMWG/Person/Edwin.V.Bell.II Get XML
↑

SPASE version 2.0.0

Person: Prof. Edward C. Stone, Jr.

Name
Prof. Edward C. Stone, Jr.
Organization
California Institute of Technology
Email
ecs@srl.caltech.edu
Phone
+1-626-395-8321
Person ID
spase://SMWG/Person/Edward.C.Stone.Jr Get XML
Release date
2001-04-02 00:00:00
↑

SPASE version 1.2.0

Repository: NSSDC

Repository ID
spase://SMWG/Repository/NASA/NSSDC Get XML
Name
NSSDC
Description

National Space Science Data Center

Contact
Role Person
1. General contact Dr. Edwin J. Grayzeck, Jr. Get XML
2. General contact Dr. Edwin V. Bell, II Get XML
Release date
2008-08-26 21:02:30
Prior ID
spase://SMWG/Repository/NSSDC
↑