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Martian Landing was a concept for television for which a script exists in the Henson Archives dated April 1965. Jim Henson drew several pages of alien landscapes and creatures (one page of which is reproduced in Jim Henson's Designs and Doodles). The idea was inspired by the NASA space program.
The script treatment describes the set and opening dialogue as follows:
A MARTIAN LANDSCAPE. IN THE FOREGROUND, TWO ROUNDED, POCK-MARKED HILLS. BEHIND IS A DESOLATE, CRAGGY MOUNTAIN RANGE, AND AN ENDLESS, VELVET BLACK SKY. THE SOUND OF STRONG WINDS BLOWING.
THEN, ELECTRONIC SOUNDS, STATIC RADIO SIGNALS, TELEMETRY. THE VOICE OF CAPE KENNEDY CONTROL IS HEARD FROM EARTH.
VOICE
This is Cape Kennedy Control. Telemetry now indicates that Voyager I, the robot controlled laboratory, is on schedule, all systems go. Voyager I should impact on the surface of Mars in eight seconds...seven...six...five...four...etc.
THE SOUND OF ROCKETS APPROACHING. VOYAGER I DESCENDS SLOWLY AND LANDS ON THE SURFACE OF MARS. ITS METAL LEGS STRADDLING THE TWO HILLS. THE UPPER PART OF THIS STRANGE MACHINE IS SHAPED ROUGHLY LIKE A HEAD WITH EYES AND A MOUTH. THERE ARE OPENINGS ON EITHER SIDE OF THE BODY, OUT OF WHICH WILL EXTEND PINCER-LIKE HANDS ON FLEXIBLE STEEL ARMS. AN ANTENNA REACHES UP OVER THE HEAD. WHEN TELEMETRY IS BEING SENT BACK TO EARTH, A LIGHT ATOP OF THE ANTENNA FLASHES.
THE EXPRESSION ON THE MACHINE'S FACE LEADS US TO BELIEVE THAT HE'D RATHER BE DEAD THAN HERE ON MARS.
Muppet Morsels appearing on The Muppet Show: Season One cite Martian Landing as the original source for the Galley-oh-hoop-hoop sketch seen later in The Muppets Valentine Show in 1974 and episode 107 in 1976. After Martian Landing was not produced, the Koozbanian creatures were conceptualized for The Muppets at Lincoln Center in 1972, two years before The Muppets Valentine Show.