VLITE Marks 11 Years of Capturing the Dynamic Radio Sky

VLITE 11 year sky coverage map
Credit: NRL. Hi-Res File

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A collaboration between the U.S. Naval Research Laborato,hrry and the National Radio Astronomy Observatory celebrates over a decade of commensal observing with the VLA

The U.S. National Science Foundation National Radio Astronomy Observatory (NSF NRAO) and the U.S. Naval Research Laboratory (NRL) are celebrating the 11th anniversary of the VLA Low-band Ionosphere and Transient Experiment (VLITE), a pioneering program that has opened new windows into the low-frequency radio universe.

Launched in late 2014, VLITE operates commensally with the U.S. National Science Foundation Very Large Array (NSF VLA), continuously recording low-frequency data while the NSF VLA conducts its regular science observations. This innovative model has enabled VLITE to build an unprecedented dataset of the dynamic radio sky, without interrupting or altering the array’s primary research projects.

“VLITE was envisioned as an opportunistic experiment, but it has evolved into a powerhouse dataset for studying the ionosphere, transients, and cosmic radio emission,” said NSF VLA Director Dr. Trish Henning. “Its success demonstrates how strategic collaborations can multiply the scientific return of existing infrastructure.”

As of its 11th anniversary, VLITE has amassed a remarkable record of continuous operation and scientific impact:

Sky coverage:

98% of the sky north of –40° declination observed to 49 minutes

50% of the sky north of –40° declination observed to 190 minutes

1% of that same sky observed to 132 hours


Data production:

More than 3.8 million META files processed

66,846 hours of data collected (representing 69% of wall-clock time)

759,760 archived images


Scientific impact:

93 peer-reviewed papers using or referencing VLITE data

6,256 total citations

75,429 combined reads across those publications


Additionally, seven high-impact papers have been published in Nature, Nature Astronomy, and Science.

“The sustained productivity and science reach of VLITE highlight the value of commensal observing,” said a scientist from NRL’s Remote Sensing Division. “By listening to the low-band universe alongside the VLA, we’ve captured both expected and surprising phenomena—from ionospheric structure to astrophysical transients.”

VLITE’s success provides a crucial foundation for future low-frequency efforts at the VLA, including technology pathfinding for the next-generation VLA (ngVLA) and potential extensions of the VLITE model to expanded frequency coverage or continuous transient monitoring.

“The collaboration between NRL and NSF NRAO continues to showcase what’s possible when innovative engineering, operations, and science intersect,” said Director Trish Henning. “As we look ahead, VLITE remains a testament to what long-term vision and cooperation can achieve.”

Source: National Radio Astronomy Observatory (NRAO)/News

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Press Contacts:

Corrina Jaramillo Feldman
Sr. Public Information Officer
cfeldman@nrao.edu | Tel: +15056408189

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About VLITE

The VLA Low-band Ionosphere and Transient Experiment (VLITE) is a collaborative program between the U.S. Naval Research Laboratory and the U.S. National Science Foundation National Radio Astronomy Observatory. VLITE operates commensally with the NSF VLA, recording data in the 320–384 MHz frequency range during regular NSF VLA observations to study astrophysical and geophysical phenomena.

About NRAO

The National Radio Astronomy Observatory is a facility of the U.S. National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

About the U.S. Naval Research Laboratory

NRL is a scientific and engineering command dedicated to research that drives innovative advances for the U.S. Navy and Marine Corps from the seafloor to space and in the information domain. NRL, located in Washington, D.C. with major field sites in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 3,000 civilian scientists, engineers and support personnel.

NRL offers several mechanisms for collaborating with the broader scientific community, within and outside of the Federal government. These include Cooperative Research and Development Agreements (CRADAs), LP-CRADAs, Educational Partnership Agreements, agreements under the authority of 10 USC 4892, licensing agreements, FAR contracts, and other applicable agreements.

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When a planet behaves like a comet

 Comet-like ionosphere at Venus

Copyright ESA/Wei et al. (2012)

Hi-res (1.02mb)

ESA’s Venus Express has made unique observations of Venus during a period of reduced solar wind pressure, discovering that the planet’s ionosphere balloons out like a comet’s tail on its nightside.   

The ionosphere is a region of weakly electrically charged gas high above the main body of a planet’s atmosphere. Its shape and density are partly controlled by the internal magnetic field of the planet. 

For Earth, which has a strong magnetic field, the ionosphere is relatively stable under a range of solar wind conditions. By comparison, Venus does not have its own internal magnetic field and relies instead on interactions with the solar wind to shape its ionosphere. 

The extent to which this shaping depends on the strength of the solar wind has been controversial, but new results from Venus Express reveal for the first time the effect of a very low solar wind pressure on the ionosphere of an unmagnetised planet. 

The observations were made in August 2010 when NASA’s Stereo-B spacecraft measured a drop in solar wind density to 0.1 particles per cubic centimetre, around 50 times lower than normally observed; this persisted for about 18 hours.  

As this significantly reduced solar wind hit Venus, Venus Express saw the planet’s ionosphere balloon outwards on the planet’s ‘downwind’ nightside, much like the shape of the ion tail seen streaming from a comet under similar conditions. 

“The teardrop-shaped ionosphere began forming within 30–60 minutes after the normal high pressure solar wind diminished. Over two Earth days, it had stretched to at least two Venus radii into space,” says Yong Wei of the Max Planck Institute for Solar System Research in Germany, lead author of the new findings.

The new observations settle a debate about how the strength of the solar wind affects the way in which ionospheric plasma is transported from the dayside to the nightside of Venus.

Usually, this material flows along a thin channel in the ionosphere, but scientists were unsure what happens under low solar wind conditions. Does the flow of plasma particles increase as the channel widens due to the reduced confining pressure, or does it decrease because less force is available to push plasma through the channel?

“We now finally know that the first effect outweighs the second, and that the ionosphere expands significantly during low solar wind density conditions,” says Markus Fraenz, also of the Max Planck Institute and co-author on the paper. 

A similar effect is also expected to occur around Mars, the other non-magnetised planet in our inner Solar System. 

“We often talk about the effects of solar wind interaction with planetary atmospheres during periods of intense solar activity, but Venus Express has shown us that even when there is a reduced solar wind, the Sun can still significantly influence the environment of our planetary neighbours,” adds Håkan Svedhem, ESA’s Venus Express project scientist. 

Notes for editors:

 “A teardrop-shaped ionosphere at Venus in tenuous solar wind” by Y. Wei et al is published in Planetary and Space Science 73, 2012. 

For further information, please contact:
 
Markus Bauer 


ESA Science and Robotic Exploration Communication Officer

 

Tel: +31 71 565 6799 


Mob: +31 61 594 3 954 


Email: markus.bauer@esa.int
 


Yong Wei
Max Planck Institute for Solar System Research
E-mail: wei@mps.mpg.de

Markus Fraenz
Max Planck Institute for Solar System Research
E-mail: fraenz@mps.mpg.de
Tel: +49 555 6979 441


Håkan Svedhem
Venus Express Project Scientist
Email: H.Svedhem@esa.int
Tel: +31 71 565 3370