This month communication between Mars and Earth may be disrupted due to a planetary arrangement called Mars solar conjunction, where Mars will be passing almost directly behind the sun from Earth’s perspective. Mars solar conjunction happens once about every 26 months, and not every conjunction is the same. They vary because of the changing sun’s activity and also in terms of how close to directly behind the sun Mars gets.
In period from April 9 to 26th April, 2013 transmissions from Earth to the orbiters will be suspended while Mars and the sun are two degrees or less apart in the sky. This year the sun is in its more active period and the apparent angle between Mars and sun will slim to 0.4 degree on 17th April, 2013.
This is the sixth conjunction for NASA’s Mars Odyssey, so mission managers have plenty of useful experience dealing with them, though each conjunction is a little different. This time, Curiosity is also at Mars surface. Torsten Zorn of JPL, conjunction planning leader for Curiosity’s engineering operations team, said that they plan to maintain visibility of rover status – Curiosity will be sending daily beeps directly to Earth, and their second line of visibility is in the Odyssey relays.