TRACE

This article is about the space telescope. For the HTTP request method, see Hypertext Transfer Protocol. For a financial report, see Trade Reporting And Compliance Engine. For the speech perception model, see TRACE (psycholinguistics).

Transition Region and Coronal Explorer

250px Illustration of TRACE
Names	Explorer-73, SMEX-4
Mission type	Heliophysics
Operator	NASA / Goddard
COSPAR ID	1998-020A
SATCAT №	25280
Website	http://trace.lmsal.com/
Mission duration	Planned: 1 year Final:
Spacecraft properties
Manufacturer	NASA / Goddard Lockheed Martin
Launch mass	250 kg (551 lb)
Dimensions	1.9 × 1.1 m (6.2 × 3.6 ft)
Power	220 W
Start of mission
Launch date	April 2, 1998, 02:43:23 (1998-04-02UTC02:43:23Z) UTC
Rocket	Pegasus XL
Launch site	Stargazer Vandenberg AFB, California, U.S.
Contractor	Orbital Sciences
Entered service	April 20, 1998
Orbital parameters
Reference system	Geocentric
Regime	Sun synchronous
Semi-major axis	6,914.2 km (4,296.3 mi)
Eccentricity	0.00267
Perigee	517.6 km (321.6 mi)
Apogee	554.5 km (344.6 mi)
Inclination	97.5325°
Period	95.3667 min
RAAN	89.297°
Argument of perigee	91.5219°
Mean anomaly	32.1161°
Mean motion	15.1 rev/day
Epoch	September 10, 2015, 19:19:29
Revolution number	95290
Main telescope
Name	TRACE Imaging Telescope
Type	Cassegrain
Diameter	30 cm (12 in)
Focal length	8.66 m (28.4 ft)
Wavelengths	Ultraviolet and extreme ultraviolet
Resolution	1 arcsec
File:TRACE logo.png Small Explorer program ← SWAS WIRE →

Transition Region and Coronal Explorer (TRACE) was a NASA heliophysics and solar observatory designed to investigate the connections between fine-scale magnetic fields and the associated plasma structures on the Sun by providing high resolution images and observation of the solar photosphere and transition region to the corona. A main focus of the TRACE instrument is the fine structure of coronal loops low in the solar atmosphere. TRACE is the fourth spacecraft in the Small Explorer program, launched on April 2, 1998, and obtaining its last science image in 2010.

The satellite was built by NASA's Goddard Space Flight Center. Its telescope was constructed by a consortium led by Lockheed Martin's Advanced Technology Center. The optics were designed and built to a state-of-the-art surface finish by the Smithsonian Astrophysical Observatory (SAO). The telescope has a 30 cm (12 in) aperture and 1024×1024 CCD detector giving an 8.5 arc minute field of view. The telescope is designed to take correlated images in a range of wavelengths from visible light through the Lyman alpha line to far ultraviolet. The different wavelength passbands correspond to plasma emission temperatures from 4,000 to 4,000,000 K. The optics use a special multilayer technique to focus the difficult-to-reflect EUV light; the technique was first used for solar imaging in the late 1980s and 1990s, notably by the MSSTA and NIXT sounding rocket payloads.

Image gallery

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  TRACE image of some typical million Kelvin loops

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  Image of a sunspot taken by TRACE

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  TRACE mosaic of the full-disk Sun

External links

Media related to at Wikimedia Commons

• TRACE website by Lockheed Martin
• TRACE Data Center by Lockheed Martin
• TRACE website (archived) by NASA's Goddard Space Flight Center