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). For the kick stage by Impulse Space, see Impulse Space § Helios.

Helios A\Helios B
Prototype of the Helios spacecraft
Mission typeSolar observation
Operator
COSPAR IDHelios-A: 1974-097A
Helios-B: 1976-003A
SATCAT no.Helios-A: 7567
Helios-B: 8582
WebsiteHelios-A: [1]
Helios-B: [2]
Mission durationHelios-A: 10 years, 1 month, 2 days
Helios-B: 3 years, 5 months, 2 days
Spacecraft properties
ManufacturerMBB
Launch massHelios-A: 371.2 kg (818 lb)
Helios-B: 374 kg (825 lb)
Power270 watts (solar array)
Start of mission
Launch dateHelios-A: December 10, 1974, 07:11:01 (1974-12-10UTC07:11:01) UTC[1]
Helios-B: January 15, 1976, 05:34:00 (1976-01-15UTC05:34) UTC[2]
RocketTitan IIIE / Centaur
Launch siteCape Canaveral SLC-41
Entered serviceHelios-A: January 16, 1975
Helios-B: July 21, 1976
End of mission
DeactivatedHelios-A: February 18, 1985 (1985-02-19)
Helios-B: December 23, 1979
Last contactHelios-A: February 10, 1986
Helios-B: March 3, 1980
Orbital parameters
Reference systemHeliocentric
EccentricityHelios-A: 0.5218
Helios-B: 0.5456
Perihelion altitudeHelios-A: 0.31 AU
Helios-B: 0.29 AU
Aphelion altitudeHelios-A: 0.99 AU
Helios-B: 0.98 AU
InclinationHelios-A: 0.02°
Helios-B: 0°
PeriodHelios-A: 190.15 days
Helios-B: 185.6 days
EpochHelios-A: January 15, 1975, 19:00 UTC[1]
Helios-B: July 20, 1976, 20:00 UTC[2]

Helios-A and Helios-B (after launch renamed Helios 1 and Helios 2) are a pair of probes that were launched into heliocentric orbit to study solar processes. As a joint venture between German Aerospace Center (DLR) and NASA, the probes were launched from Cape Canaveral Air Force Station, Florida, on December 10, 1974, and January 15, 1976, respectively.

The Helios project set a maximum speed record for spacecraft of 252,792 km/h (157,078 mph; 70,220 m/s).[3] Helios-B performed the closest flyby of the Sun of any spacecraft until that time. The probes are no longer functional, but as of 2024 remain in elliptical orbits around the Sun.

  1. ^ a b Cite error: The named reference orbit3 was invoked but never defined (see the help page).
  2. ^ a b "Helios-B – Trajectory Details". National Space Science Data Center. NASA. Retrieved July 12, 2017.
  3. ^ Wilkinson, John (2012), New Eyes on the Sun: A Guide to Satellite Images and Amateur Observation, Astronomers' Universe Series, Springer, p. 37, Bibcode:2012nesg.book.....W, ISBN 978-3-642-22838-4