NASA will decide the fate of its two space missions, the Opportunity rover on Mars and the Lunar Reconnaissance Orbiter (LRO) on the moon depending on the availibity of the findings in the 2015 US budget. In the event that the U.S. space agency decides to terminate these missions would create a precedent unthinkable until very recently: cut funding rovers while still retain the ability to provide information. The situation of both missions is very delicate at the moment, since neither has received financial support in the proposed budgets of the White House in 2015. It is true that the document released by the Obama administration is only a first evaluation of the economic priorities of NASA, and Congress will have the final say. It is also true that it is not the first time that some operational mission was left out of this initial budget of the President and is rescued later by Congress. But the fact remains that Opportunity has just turned ten, and the LRO five, which means that both have already far exceeded their life expectancy.

The problem, obviously, is the shortage of funds. NASA currently maintains six major missions in the Solar System: the Cassini probe orbiting Saturn; LRO at the Moon; and four missions on Mars, Mars orbiters both Odyssey and Mars Reconnaissance Orbiter (MRO) and the two rovers Opportunity and Curiosity. All these robots (except Curiosity) have completed their initial season, some substantially. And once their initial campaign, each mission must submit to the direction of the NASA detailed reports of their ongoing activities and objectives for the future. These reports are evaluated internally to develop a list that determines which missions have priority for funding for two more years. This process was repeated several times every two years, and this year the reports were submitted in mid-April.

The problem this time is that the Curiosity entered in the calculations for the first time, and although the budget of the Division for Planetary Sciences of NASA has increased slightly over the previous year, the Curiosity is a mission that requires substantial funding. Ultimately, NASA does not have sufficient funds to cover 100% two years of the six missions: fully meet the needs of all of them would be about 20 % additional budget on actually available. Therefore, what the White House has proposed has been directly eliminate two missions whose costs combined represent almost exactly the amount you need to trim. Once you know the President’s budget, NASA has put on the table the option to finance the six missions, but every part, so that the effort is distributed evenly. But this is a solution that pleases no one and, in fact, could complicate the proper conduct of all missions.

Where does that leave this lack of funds to six major missions? In principle, Cassini and Curiosity should be safe. While the former leads orbiting Saturn since 2004, and therefore is already enjoying an extension of its initial campaign, its scientific return has been spectacular: from the 100 flybys of Titan that have confirmed the existence of seas of methane and liquid ethane in the largest moon of Saturn, until eruptions of icy material that suggest the existence of a subsurface ocean on Enceladus, including the study of the planet’s rings or the analysis of its smaller moons.

For its part, arrived at Mars Curiosity in August 2012, and has since provided a huge amount of valuable data. Since the confirmation that liquid water flowed across the Martian surface for a sufficiently long time to round the rocks of the river channels (as happens on Earth), until the discovery that collect sediment geochemical evidence that the planet was living at some point in the past, going through the preliminary detection of organic compounds for the first time on its surface. Curiosity has obtained a success of this magnitude so far it’s hard to imagine not receive funds to continue their operations, especially since it would only be the first extension of its initial campaign.

The two Mars orbiters are already veterans. The MRO has been in Mars orbit since 2006, and has provided unprecedented detail information about the mineralogical variety of the Martian surface, and high resolution orbital images. The Odyssey has already served 12 years in Mars (the record of an orbiter outside the Earth), and has given us a detailed description of the distribution of minerals on the surface of water ice in the subsurface, although some of its instruments while not working. But both have an important asset in their favor: they are the only two NASA satellites that are orbiting Mars, and therefore are channel employing agency to transmit to Earth the data they collect on the surface missions.

Robots that operate on the surface can communicate directly with Earth, but ten times slower and inefficient that the form provided by the orbiters. NASA will seriously consider this capability in its final assessment of funding priorities, especially considering that you already have on the way the following robotic platform that has to land on the surface (InSight, in September 2016) and is already preparing the next rover, which will be shipped in 2020. Consequently, the continuity of the two orbiters seems essential. The Odyssey has a capacity of transmission smaller than MRO, but the only available plan b if the MRO is disrupted. It is true that a new orbiter MAVEN, is underway and will orbit Mars in September this year with a mandate to study the planet’s atmosphere; but the MAVEN only be used as emergency transmitter during its initial two-year campaign, apart from the characteristics of its orbit will make it even less effective as transmitter Odyssey.

Therefore, the LRO and Opportunity will have to compete hard to get funding and keep active two more years. It will be difficult. The LRO was sent to the moon with a mission to map possible landing sites for manned missions, a task that already completed in the first year. Also, today, NASA has no plans to return to the Moon at least in the coming decades.

The author, Alberto Gonzalez Fairén, a researcher at the Department of Astronomy at Cornell University in New York ( USA), and Center for Astrobiology ( CSIC) in Madrid, and is a member of the science teams of Curiosity and Opportunity rovers .