NASA has prompted widespread speculation of a historic discovery on Mars by scheduling a date for an announcement but refusing to say what it is.
Excitement is building over soon-to-be-released results from NASA's Curiosity rover, which is three months into a two-year mission to determine if Mars has ever been capable of supporting microbial life.
The rover's Sample Analysis at Mars (SAM) instruments have been sending back information as it hunts for compounds such as methane, as well as hydrogen, oxygen and nitrogen, that could provide such evidence.
In an interview with US broadcaster National Public Radio, aired Tuesday, lead mission investigator John Grotzinger hinted at something major but said there would be no announcement for several weeks.
"We're getting data from SAM," he said. "This data is gonna be one for the history books. It's looking really good."
But a spokesperson for NASA's Jet Propulsion Laboratory was quick to downplay rumours of a major scientific breakthrough.
"John was delighted about the quality and range of information coming in from SAM during the day a reporter happened to be sitting in John's office last week. He has been similarly delighted by results at other points during the mission so far," the spokesperson, Guy Webster, said.
"The scientists want to gain confidence in the findings before taking them outside of the science team. As for history books, the whole mission is for the history books."
NASA scientists do not expect the rover to find aliens or living creatures but hope to analyse soil and rocks for signs of life which may have existed in the past.
US President Barack Obama has vowed to send humans to the planet by 2030.
Author: Bernadette Chua, Approving Editor: Emily O'Keefe