Helios (spacecraft)

*Helios A*\*Helios B*
	Prototype of the Helios spacecraft
Mission type	Solar observation
Operator	NASA; DFVLR;
COSPAR ID	Helios-A: 1974-097A ; Helios-B: 1976-003A
SATCAT no.	Helios-A: 7567 ; Helios-B: 8582
Website	Helios-A: [1] ; Helios-B: [2]
Mission duration	Helios-A: 10 years, 1 month, 2 days ; Helios-B: 3 years, 5 months, 2 days
Spacecraft properties
Manufacturer	MBB
Launch mass	Helios-A: 371.2 kg (818 lb); Helios-B: 374 kg (825 lb)
Power	270 watts (solar array)
Start of mission
Launch date	Helios-A: December 10, 1974, 07:11:01 UTC ; Helios-B: January 15, 1976, 05:34:00 UTC
Rocket	Titan IIIE / Centaur
Launch site	Cape Canaveral SLC-41
Entered service	Helios-A: January 16, 1975 ; Helios-B: July 21, 1976
End of mission
Deactivated	Helios-A: February 18, 1985 ; Helios-B: December 23, 1979
Last contact	Helios-A: February 10, 1986 ; Helios-B: March 3, 1980
Orbital parameters
Reference system	Heliocentric
Eccentricity	Helios-A: 0.5218 ; Helios-B: 0.5456
Perihelion altitude	Helios-A: 0.31 AU ; Helios-B: 0.29 AU
Aphelion altitude	Helios-A: 0.99 AU ; Helios-B: 0.98 AU
Inclination	Helios-A: 0.02° ; Helios-B: 0°
Period	Helios-A: 190.15 days ; Helios-B: 185.6 days
Epoch	Helios-A: January 15, 1975, 19:00 UTC ; Helios-B: July 20, 1976, 20:00 UTC

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.

^ ^a ^b Cite error: The named reference orbit3 was invoked but never defined (see the help page).
^ ^a ^b "Helios-B – Trajectory Details". National Space Science Data Center. NASA. Retrieved July 12, 2017.
^ 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

[orbit3-1] Cite error: The named reference orbit3 was invoked but never defined (see the help page).

[nssdc-h2-2] "Helios-B – Trajectory Details". National Space Science Data Center. NASA. Retrieved July 12, 2017.

[wilkinson2012-3] 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

[1]

[2]

[3]

Spacecraft properties
Prototype of the Helios spacecraft

Mission type	Solar observation
Operator	NASA DFVLR
COSPAR ID	Helios-A: 1974-097A Helios-B: 1976-003A
SATCAT no.	Helios-A: 7567 Helios-B: 8582
Website	Helios-A: [1] Helios-B: [2]
Mission duration	Helios-A: 10 years, 1 month, 2 days Helios-B: 3 years, 5 months, 2 days


Manufacturer	MBB
Launch mass	Helios-A: 371.2 kg (818 lb) Helios-B: 374 kg (825 lb)
Power	270 watts (solar array)


Start of mission
Launch date	Helios-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]
Rocket	Titan IIIE / Centaur
Launch site	Cape Canaveral SLC-41
Entered service	Helios-A: January 16, 1975 Helios-B: July 21, 1976


End of mission
Deactivated	Helios-A: February 18, 1985 (1985-02-19) Helios-B: December 23, 1979
Last contact	Helios-A: February 10, 1986 Helios-B: March 3, 1980


Orbital parameters
Reference system	Heliocentric
Eccentricity	Helios-A: 0.5218 Helios-B: 0.5456
Perihelion altitude	Helios-A: 0.31 AU Helios-B: 0.29 AU
Aphelion altitude	Helios-A: 0.99 AU Helios-B: 0.98 AU
Inclination	Helios-A: 0.02° Helios-B: 0°
Period	Helios-A: 190.15 days Helios-B: 185.6 days
Epoch	Helios-A: January 15, 1975, 19:00 UTC^[1] Helios-B: July 20, 1976, 20:00 UTC^[2]