Answer

Yes, if both special landing spaces on Mars are still available, two players can take them in the same round, and both will receive the first-landing bonuses.

Rulebook Support

• On page 11, it states:

  "The first player to land on a planet also receives some data. To remind everyone that later landers will not gain this data, cover the space with your figure. (Mars is unique as it has two of these spaces instead of just one. If you're one of the first two to land on Mars, choose one of the spaces to cover.)"

• This means:

  • Mars has two special first-landing spaces.
  • The first two players to land on Mars each cover one of these spaces.
  • Each of these spaces grants the first-landing bonus (including data).
  • There is no rule preventing two players from landing on Mars in the same round and each claiming one of the first-landing spaces, as long as both are available when they land.

Summary

Both players can take the special landing spaces on Mars in the same round if they are available, and both receive the first-landing bonuses.

Source: page 11

Source: Core Rulebook (pp. 11, 17, 25, 28, 8)