In 1969 the Mariner 6 and Mariner 7 spacecraft to Mars were in the same part of the sky and both in view of a DSN site at the same time, though not within the beamwidth of a single antenna. Tracking both simultaneously required two antennas and two telemetry data processors, one for each downlink. At the same time the interplanetary Pioneer spacecraft were tracked and backup support for Apollo was required.