História sobre astronautas que dispararam um farol de alerta alienígena na lua (ou em Marte?)

Você está descrevendo " The Sentinel " de Arthur C. Clarke, a história que se tornou a base para a seqüência da lua no filme 2001: Uma Odisséia no Espaço.

Por wikipedia

The story deals with the discovery of an artifact on Earth's Moon left behind eons ago by ancient aliens. The object is made of a polished mineral, is tetrahedral in shape, and is surrounded by a spherical forcefield. The narrator speculates at one point that the mysterious aliens who left this structure on the Moon may have used mechanisms belonging "to a technology that lies beyond our horizons, perhaps to the technology of para-physical forces."

The narrator speculates that for millions of years (evidenced by dust buildup around its forcefield) the artifact has been transmitting signals into deep space, but it ceases to transmit when, sometime later, it is destroyed "with the savage might of atomic power". The narrator hypothesizes that this "sentinel" was left on the moon as a "warning beacon" for possible intelligent and spacefaring species that might develop on Earth.

In 2001: A Space Odyssey, the operation of the sentinel is activated when sunlight touches it for the first time after it was dug up.

Você pode ler on-line aqui .

Enquanto isso poderia ser "The Sentinel", outra possibilidade é 2001: Uma Odisséia no Espaço , o trabalho mais conhecido no qual o conto cresceu. É tanto um filme de Stanley Kubrick quanto um livro de Arthur C. Clarke, desenvolvidos juntos.

O objeto é conhecido como TMA-1, para Tycho Magnetic Anomaly One.

"The first party discovered nothing - just the usual level terrain, buried beneath a very thin layer of moon-dust. They sank a drill in the exact center of the magnetic field to get a core sample for study. Twenty feet down, the drill stopped. So the survey party started to dig - not an easy job in spacesuits, as I can assure you.
"What they found brought them back to Base in a hurry. We sent out a bigger team, with better equipment. They excavated for two weeks - with the result you know."

(...)

The object before which the spacesuited man was posing was a vertical slab of jet-black material, about ten feet high and five feet wide: it reminded Floyd, somewhat ominously, of a giant tombstone. Perfectly sharp-edged and symmetrical, it was so black it seemed to have swallowed up the light falling upon it; there was no surface detail at all. It was impossible to tell whether it was made of stone or metal or plastic - or some material altogether unknown to man.

(...)

"You see, it is approximately three million years old. What you are now looking at is the first evidence of intelligent life beyond the Earth."

Quando totalmente escavado e tocado pelo sol pela primeira vez, ele envia um "grito eletrônico penetrante".

Floyd was still musing over these thoughts when his helmet speaker suddenly emitted a piercing electronic shriek, like a hideously overloaded and distorted time signal. Involuntarily, he tried to block his ears with his spacesuited hands; then he recovered and groped frantically for the gain control of his receiver. While he was still fumbling four more of the shrieks blasted out of the ether; then there was a merciful silence.
All around the crater, figures were standing in attitudes of paralyzed astonishment. So it's nothing wrong with my gear, Floyd told himself; everyone heard those piercing electronic screams.
After three million years of darkness, TMA-1 had greeted the lunar dawn.