''Humanity Star'' was a reflective
passive satellite
{{about, the satellite by its functional type, the satellite by its orbital parameters, :Satellites by orbit
Categories by type ...
designed to produce visible, pulsing
flares
A flare, also sometimes called a fusée, fusee, or bengala in some Latin-speaking countries, is a type of pyrotechnic that produces a bright light or intense heat without an explosion. Flares are used for distress signaling, illumination, o ...
. The satellite was launched into orbit by an
Electron rocket
Electron is a two-stage, partially recoverable orbital launch vehicle developed by Rocket Lab, an American aerospace company with a wholly owned New Zealand subsidiary. Electron was developed to service the commercial small satellite launch mar ...
on 21 January 2018 and
entered into the atmosphere on 22 March 2018. The reaction to ''Humanity Star'' was mostly negative by astronomers, as it interferes with their observations.
Design
''Humanity Star'' was designed to produce
flares
A flare, also sometimes called a fusée, fusee, or bengala in some Latin-speaking countries, is a type of pyrotechnic that produces a bright light or intense heat without an explosion. Flares are used for distress signaling, illumination, o ...
visible from Earth.
The satellite was shaped like a
geodesic sphere
A geodesic polyhedron is a convex polyhedron made from triangles. They usually have icosahedral symmetry, such that they have 6 triangles at a vertex, except 12 vertices which have 5 triangles. They are the dual of corresponding Goldberg polyhed ...
about in diameter, with its 76 reflective panels on the shape make it looks similar to a large
disco ball
A disco ball (also known as a mirror ball or glitter ball) is a roughly spherical object that reflects light directed at it in many directions, producing a complex display. Its surface consists of hundreds or thousands of facets, nearly all of ...
. It is made out of
carbon fiber
Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
and weigh .
According to Rocket Lab, ''Humanity Star'' was meant to be "a bright symbol and reminder to all on Earth about our fragile place in the universe".
Launch and orbit
''Humanity Star'' was launched on 21 January 2018 at 01:43
UTC from
Rocket Lab Launch Complex 1
Rocket Lab Launch Complex 1 (also known as Mahia Launch Complex or Spaceport) is a commercial spaceport located close to Ahuriri Point at the southern tip of Māhia Peninsula, on the east coast of New Zealand's North Island. It is owned and op ...
, located on the
Māhia Peninsula
Māhia Peninsula (Maori: or ) is located on the east coast of New Zealand's North Island, in the Hawke's Bay region, between the towns of Wairoa and Gisborne.
Rocket Lab has set up its Launch Complex 1 close to Ahuriri Point at the southe ...
of New Zealand.
It orbited the Earth every 92 minutes in a
polar orbit
A polar orbit is one in which a satellite passes above or nearly above both poles of the body being orbited (usually a planet such as the Earth, but possibly another body such as the Moon or Sun) on each revolution. It has an inclination of about ...
of approximately in altitude.
According to Rocket Lab, the satellite's orbit was expected to
decay
Decay may refer to:
Science and technology
* Bit decay, in computing
* Software decay, in computing
* Distance decay, in geography
* Decay time (fall time), in electronics
Biology
* Decomposition of organic matter
* Tooth decay (dental caries) ...
after nine months, eventually burning up completely in Earth's atmosphere.
However, the satellite
re-entered several months early on 22 March 2018 at about 13:15 UTC.
The quick entry could be caused by the ''Humanity Star''
's low density, amplifying
atmospheric drag
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding flu ...
effects.
Because of its highly reflective surface, Rocket Lab claimed that ''Humanity Star'' could be seen by the
naked eye
Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collecting optical instrument, such as a telescope or microscope, or eye protection. Vision corrected to normal ...
from the surface of the Earth. Its apparent brightness was estimated to be
magnitude
Magnitude may refer to:
Mathematics
*Euclidean vector, a quantity defined by both its magnitude and its direction
*Magnitude (mathematics), the relative size of an object
*Norm (mathematics), a term for the size or length of a vector
*Order of ...
7.0 when half illuminated and viewed from a distance of , while its maximum brightness was estimated to be magnitude 1.6.
The satellite was most likely to be visible in the night sky at dawn or dusk.
Its orbit could be tracked by
Heavens-Above
Heavens-Above is a non-profit website developed and maintained by Chris Peat as ''Heavens-Above GmbH''. The web site is dedicated to helping people observe and track satellites orbiting the Earth without the need for optical equipment such as bi ...
and the satellite's website.
Analysis
Initial reactions by astronomers were negative, since reflective objects in orbit interferes with astronomical observations.
It has been described as an act of vandalism of the night sky, space
graffiti
Graffiti (plural; singular ''graffiti'' or ''graffito'', the latter rarely used except in archeology) is art that is written, painted or drawn on a wall or other surface, usually without permission and within public view. Graffiti ranges from s ...
,
a "publicity stunt"
and "glittery space garbage".
Others however argue that flares by existing satellites and the
ISS
The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA (J ...
are much brighter than ''Humanity Star''.
Alice Gorman
Alice Gorman (born 1964) FSA is an Australian archaeologist, heritage consultant, and lecturer, who is best known for pioneering work in the field of space archaeology and her Space Age Archaeology blog. Based at Flinders University, she is an ...
postulates that ''Humanity Star'' and
Elon Musk's Tesla Roadster
Elon Musk's Tesla Roadster is an electric sports car that served as the dummy payload for the February 2018 Falcon Heavy test flight and became an artificial satellite of the Sun. A mannequin in a spacesuit, dubbed "Starman", occupies the dr ...
are statements with very different but related messages: while ''Humanity Star'' may be seen as promoting a unifying vision and the Roadster as a reminder of inequality, "each tells the story of attitudes to space at a particular point in time."
See also
*
KiwiSAT
*
Light pollution
Light pollution is the presence of unwanted, inappropriate, or excessive use of artificial Visible spectrum, lighting. In a descriptive sense, the term ''light pollution'' refers to the effects of any poorly implemented lighting, during the day ...
*
Lincoln Calibration Sphere 1
The Lincoln Calibration Sphere 1, or LCS-1, is a large aluminium sphere in Earth orbit since 6 May 1965. It is still in use, having lasted for over 50 years. The sphere was launched along with the Lincoln Experimental Satellite-2 on a Titan IIIA ...
*
Project Echo
Project Echo was the first passive communications satellite experiment. Each of the two American spacecraft, launched in 1960 and 1964, were metalized balloon satellites acting as passive reflectors of microwave signals. Communication sign ...
References
External links
*
{{Use dmy dates, date=January 2018
2018 in New Zealand
2018 controversies
Passive satellites
Spacecraft launched in 2018
Spacecraft which reentered in 2018
Satellites of New Zealand
Spacecraft launched by Electron rockets