If they are right, and high-resolution images from a new NASA mission to Mars next year could provide the hard proof they need, the path could be cleared for a potential Beagle 3 mission to unravel the secrets of the red planet.
"The first time we actually felt we were on to something was at the end of the summer," Professor Colin Pillinger of the Open University in Milton Keynes, central England said.
"We've been over this and around it and over again... If we're right, then there are a lot of things that we don't have to do (on a new spacecraft) other than tweak a little."
Beagle 2, resembling a silver pocket watch when folded and jammed packed with high-tech instrumentation, rode piggy-back to Mars aboard the European Space Agency's Mars Express, from which it separated on December 19, 2003.
It should have landed on Mars on Christmas Day and unfolded its array of instruments, but it never sent a signal to Earth, frustrating the nearly 50 million pound (US$87.7 million dollar) mission.
It was declared lost the following February, but the mutton-chopped
Professor Pillinger, who became a TV personality with his terrier-like enthusiasm in the face of setback, never gave up delving into the possible causes.
Crater disturbance
Firm clues eventually came out of images from the NASA spacecraft Mars Global Surveyor which revealed signs of a disturbance in a crater close to the intended landing site, in a near-equatorial region called Isidis Planitia.
NASA's Mars Reconnaissance Orbiter spacecraft, which is to reach Mars in March next year, is expected to supply more proof.
Once in orbit, Professor Pullinger said, it will be able to scan the surface with unprecedented image quality.
"There is a lot of disturbance in this crater, particularly a big patch on the north crater wall which we think is the primary impact site," the scientist told BBC television.
"There are then other features around the crater consistent with the airbags bouncing around and finally falling down into the middle. Then, when you cut the lace, the airbags fall apart giving three very symmetrical triangles.”
Professor Pullinger speculated that the impact of the landing may have damaged onboard instruments and prevented communication.
It also may have hit the ground too hard because the atmosphere was thinner than normal due to nearby dust storms at the time, he explained.
But he told Agence France Presse: "We think 'wreckage' is too strong a word. We are actually thinking that is is very much intact."
Professor Pillinger said his team's hypothesis has been put to experts who make their living reading satellite images, not necessarily those from Mars, and that they have found it credible.