Subscribe to our free daily newsletters
. 24/7 Space News .

Subscribe to our free daily newsletters

The Radar Search For Martian Water

Mars Express in orbit around Mars with MARSIS antenna unfurled
Dublin - Apr 22, 2003
Until the last few years, Mars has been regarded as a cold, arid world that lost most of its water long ago. However, recent observations by NASA's Mars Global Surveyor and Mars Odyssey spacecraft have provided tantalising evidence that huge amounts of water may be hidden just below the surface.

Now, a powerful new instrument is poised to probe the Martian soil, using an advanced radar system to penetrate the rust-red desert. On Friday 11 April, Professor Iwan Williams (Queen Mary) presented to the UK National Astronomy Meeting how the MARSIS experiment on board the European Space Agency's Mars Express mission will search for the elusive water several kilometres beneath the planet's surface.

MARSIS is a type of ground penetrating radar. On Earth, such radar is typically operated from the ground or from aircraft to prospect for water or man-made objects a few tens of metres below ground.

On Mars, it will search for water up to 5 km below ground from its vantage-point on board Mars Express, 250-300 km above the planet.

This technique has only been tried once before on a space mission, in a successful experiment during one of the Apollo lunar missions. However, MARSIS will be the first such radar to look for underground water on another planet.

The entire instrument, including antenna and data processing unit, weighs about 12 kg. It works by sending long wavelength, low frequency radio waves

(1. 3-5.5 MHz) towards the planet from a 40 metre long antenna, which will be unfurled after Mars Express goes into a near-polar orbit. Such a long antenna is needed to work at long wavelengths, which are able to penetrate Mars to a depth of a few kilometres.

The radio waves will be reflected from any surface they encounter. Most of them will bounce off the rough surface of Mars. But because of the low frequency, a significant fraction will travel through the crust to encounter further interfaces between layers of different material.

If there is a layer containing liquid water, it should generate a radar echo. The presence of weaker signals after the first strong surface return will allow the detection of subsurface interfaces, while the time delay between the two signals will give a measure of the depth of the interfaces.

By sending two different frequencies at the same time and analysing the echoes generated, MARSIS will be able to extract information on the electrical properties of the reflecting surface and hence its composition. An underground zone of liquid water will have very different electrical properties from the surrounding rocks and will reflect very strongly.

The top of a liquid zone somewhere in the upper 2-3 km should be seen fairly easily. If other conditions are favourable, the surface may be 'seen' even at depths of 5 km or more.

"The radio waves will be reflected at any interface, not just that between rock and water," said Professor Williams, "so MARSIS should also reveal much about the composition of the top 5 km of crust in general.

It should, for example, pick out layers of rock interspersed with ice, which are more likely to exist close to the Martian surface than liquid water."

Professor Iwan Williams is one of the Co-investigators on the MARSIS experiment. Principal Investigator for the MARSIS experiment is Professor Giovanni Piccardi (University of Rome).

Mars Express is due for launch from Baikonur Cosmodrome in May 2003. It will be carrying 6 experiments in addition to the MARSIS radar. Also hitching a ride will be the UK-built Beagle 2, which will land on the Red Planet around Christmas 2003 and carry out a search for signs of primitive life -- past or present.

Related Links
Europe's Quest For Martian Water
Search SpaceDaily
Subscribe To SpaceDaily Express

Odyssey Points To Melting Snow As Cause Of Gullies
Pasadena - Feb 20, 2003
Images from the Mars Odyssey spacecraft, combined with those from Mars Global Surveyor, suggest melting snow is the likely cause of the numerous eroded gullies first documented on Mars in 2000 by Global Surveyor. The martian gullies were created by trickling water from melting snow packs, not underground springs or pressurized flows, as previously suggested, argues Dr. Philip Christensen, principal investigator for Odyssey's camera system.

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.