Astronomical Netherlands Satellite

Infobox Space telescope
name = Astronomical Netherlands Satellite (ANS)


caption = The flight spare for the satellite
organization = NISR / NASA
major_contractors =
alt_names = Astronomische Nederlandse Satelliet
nssdc_id =
location =
orbit_type =
height = 266 to 1176 km
period = 99.2 min
velocity =
accel_gravity =
launch_date = 30 August 1974
launch_location = Vandenberg AFB, USA
launch_vehicle =
mission_length = 20 months
deorbit_date =
wavelength = X-ray and ultraviolet
mass =
website =
style =
diameter =
area =
focal_length =
instrument_1_name = Hard X-Ray
instrument_1_characteristics = 1.5 to 30 KeV
instrument_2_name = Ultraviolet
instrument_2_characteristics = nowrap|5 channels, 150 to 330 nm
stats_ref = cite web |url=http://nssdc.gsfc.nasa.gov/nmc/spacecraftOrbit.do?id=1974-070A |title=NASA — NSSDC — Spacecraft — Details (ANS) |publisher=NASA |accessdate=2008-02-27] cite web |url=http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1974-070A |title=NASA — NSSD — Spacecraft — Trajectory Details (ANS) |publisher=NASA |accessdate=2008-02-27] cite journal |title=The Hard X-ray experiment on the Astronomical Netherlands Satellite |last=Gursky |first=H. |coauthors=et al. |journal=Astrophysical Journal |volume=201 |date=1 November 1975 |pages=L127–L131 |url=http://adsabs.harvard.edu/abs/1975ApJ...201L.127G |doi=10.1086/181958] cite journal |title=The ultraviolet experiment onboard the astronomical Netherlands satellite — ANS |last=van Duinen |first=R. J |coauthors=et al. |journal=Astronomy and Astrophysics |volume=39 |month=February |year=1975 |pages=159–163 |url=http://adsabs.harvard.edu/abs/1975A&A....39..159V]

The Astronomical Netherlands Satellite (ANS; also known as Astronomische Nederlandse Satelliet) was a space-based X-ray and ultraviolet telescope. It was launched into Earth orbit on 30 August 1974 at 14:07:39 UTC in a Scout rocket from Vandenberg Air Force Base, United States. The mission ran for 20 months until June 1976, and was jointly funded by the Netherlands Institute for Space Research and NASA. ANS was the first Dutch satellite, and the Main Belt asteroid 9996 ANS was named after it.cite web | url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=9996%20ANS;orb=0;cov=0;log=0 | title=JPL Small-Body Database Browser | publisher=JPL, NASA | accessdate=2008-03-03]

The telescope had an initial orbit of with a periapsis of convert|266|km|mi, an apoapsis of convert|1176|km|mi, with inclination 98.0° and eccentricity 0.064048, giving it a period of 99.2 minutes. The orbit was sun-synchronous, and the altitude of the spacecraft could be controlled via magnetic coils that interacted with the Earth's magnetic field, as well as by reaction wheels. The satellite also had two masses that were ejected early in the mission, which removed most of the satellite's angular momentum. The altitude could be measured by a variety of techniques, including solar sensors, horizon sensors, star sensors and a magnetometer.

ANS could measure X-ray photons in the energy range 2 to 30 KeV, with a 60 cm$^2$ detector, and was used to find the positions of galactic and extragalactic X-ray sources. It also measured their spectra, and looked at their variations over time. It discovered X-ray bursts, and also detected X-rays from Capella.

ANS also observed in the ultraviolet part of the spectrum, with a 22 cm (260 cm$^2$) Cassegrain telescope. The wavelengths of the observe photons were between 150 and 330 nm, with the detector split into five channels with central wavelengths of 155, 180, 220, 250 and 330 nm. At these frequencies it took over 18,000 measurements of around 400 objects.

References

Further reading

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See also

* List of space telescopes
* Ultraviolet astronomy
* X-ray astronomy