NASA's Mars Program Planning Group (MPPG) is starting to research its next Mars mission and is looking for help from scientists and engineers worldwide.
The aim is to find a relatively low-cost way of sending a robotic mission to Mars in 2018 or 2020. It should help pave the way for sending humans to Mars in the 2030s.
However, the effort will be hampered by the 21 percent budget cut to planetary science included in President Obama's 2013 budget.
"We're moving quickly to develop options for future Mars exploration missions and pathways," says John Grunsfeld, associate administrator for NASA's Science Mission Directorate.
"As part of this process, community involvement, including international, is essential for charting the new agency-wide strategy for our future Mars exploration efforts."
Scientists and technicians are being asked to submit ideas and abstracts online, wit the most promising to be presented during a workshop in June hosted by the Lunar and Planetary Institute in Houston.
"Receiving input from our community is vital to energize the planning process," says Doug McCuistion, director of the Mars Exploration Program.
"We'll integrate inputs to ensure the next steps for the Mars Exploration Program will support science, as well as longer-term human exploration and technology goals."
Several Mars missions are already in place. In August, the Mars Science Laboratory, Curiosity, will land on the planet's surface with the aim of discovering whether Mars has ever been able to support life - and whether there may be life present even now.
In 2013, NASA will launch the Mars Atmosphere and Volatile Evolution (MAVEN)orbiter, the first mission devoted to understanding the Martian upper atmosphere.