Helios (spacecraft)

This article is about the solar orbiting spacecraft. For the NASA experimental aircraft, see Helios Prototype. For French military photo-reconnaissance satellites, see Helios 1B and Helios 2 (satellite).
Helios A / Helios B

Prototype of the Helios spacecraft
Operator DFVLR / NASA
Major contractors MBB
Mission type Orbiters
Launch date Helios-A : 1974-12-10 07:11:01.5 UTC
(41 years, 4 months and 27 days ago)
Helios-B : 1976-01-15 05:34:00 UTC
(40 years, 3 months and 22 days ago)
Launch vehicle Titan IIIE / Centaur
Launch site Space Launch Complex 41
Cape Canaveral Air Force Station
Mission duration Helios-A :
January 16, 1975 to
February 18, 1985
Helios-B :
July 21, 1976 to
December 23, 1979
Satellite of Sun
COSPAR ID Helios-A : 1974-097A
Helios-B : 1976-003A
Homepage Helios-A : NASA Solarsystem Exploration page
Helios-B : NASA Solarsystem Exploration page
Mass 370 kg (820 lb)
Power (solar array)

Helios-A and Helios-B (also known as Helios 1 and Helios 2), are a pair of probes launched into heliocentric orbit for the purpose of studying solar processes. A joint venture of West Germany's space agency DFVLR (70% share) and NASA (30%), the probes were launched from Cape Canaveral, Florida, on Dec. 10, 1974, and Jan. 15, 1976, respectively. Built by Messerschmitt-Bölkow-Blohm as the main contractor they were the first spaceprobes built outside the US or USSR.

The probes are notable for having set a maximum speed record among spacecraft at 252,792 km/h[1] (157,078 mi/h or 43.63 mi/s or 70.22 km/s or 0.000234c). Helios 2 flew three million kilometers closer to the Sun than Helios 1, achieving perihelion on 17 April 1976 at a record distance of 0.29 AU (or 43.432 million kilometers),[2] slightly inside the orbit of Mercury. Helios 2 was sent into orbit 13 months after the launch of Helios 1. The Helios space probes completed their primary missions by the early 1980s, but they continued to send data up to 1985. The probes are no longer functional but still remain in their elliptical orbit around the Sun.

Mission background


Scientific instruments

Instrument Name Description
Plasma Experiment Investigation
 Measures the velocity and distribution of the solar wind plasma.
Flux-gate Magnetometer
 Measures the field strength and direction of low frequency magnetic fields in the Sun’s environment.
Search Coil Magnetometer
 Complements the Flux-Gate Magnetometer by measuring the magnetic fields between 0 and 3 kHz.
Plasma Wave Investigation
 Measures and analyzes waves of free ions and electrons in the solar wind plasma, 10 Hz to 3 MHz region.
Cosmic Radiation Investigation
 Measures protons, electrons and x-rays to determine the distribution of cosmic rays.
Low-Energy Electron and Ion Spectrometer
 Investigates the higher energy portion of the crossover region between the solar wind particles and the cosmic rays.
Zodiacal Light Photometer
 Measures the scattering of sunlight by interplanetary dust particles.
Micrometeoroid Analyser
 Investigates the composition, charge, mass, velocity and direction of interplanetary dust particles.

Mission profile

Helios I sitting atop the Titan IIIE / Centaur launch vehicle
Helios-A sitting atop the Titan IIIE / Centaur launch vehicle.

Launch and trajectory

Trajectory of the Helios space probes.

Timeline of travel

Date Event
1974-12-10
 Launch of Helios-A
1976-01-15
 Launch of Helios-B
1976-04-17
 Closest flyby of the Sun of any spacecraft, performed by Helios II.

Gallery

Launch configuration diagram
Launch configuration diagram. 
A technician stands next to one of the twin Helios spacecraft
A technician stands next to one of the twin Helios spacecraft. 
Inspection of Helios 2
Inspection of Helios-B. 
Helios probe being encapsulated for launch
A Helios probe being encapsulated for launch. 

See also

References

  1. ↑ Wilkinson, John (2012), New Eyes on the Sun: A Guide to Satellite Images and Amateur Observation, Astronomers' Universe Series, Springer, p. 37, ISBN 3-642-22838-0
  2. ↑ Solar System Exploration: Missions: By Target: Our Solar System: Past: Helios 2

External links

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