As we know there are crewed mission plans to go to Mars and people has been in the Moon already. Has there ever been crewed mission plans by any Space Agency, to go to a solar system object other than the Moon and Mars, such as Ceres or an asteroid?

  • $\begingroup$ By the way, Ceres is the largest object in the main asteroid belt. So Ceres is an asteroid too but a very large one. $\endgroup$
    – Uwe
    Commented Feb 13, 2020 at 23:08
  • $\begingroup$ The Asteroid Redirect Crewed Mission kind of counts, though IIRC humans wouldn't have gone farther than lunar orbit. $\endgroup$
    – DylanSp
    Commented Feb 14, 2020 at 13:43
  • $\begingroup$ @uwe whether Ceres is an asteroid is a little fuzzy because it was rendered a dwarf planet in 2006. It could be both, of course, but I think some people (not all) use only the dwarf planet classification. $\endgroup$ Commented Mar 21, 2020 at 19:52

4 Answers 4


Yes, NASA did consider a crewed flyby of Venus using Saturn/Apollo hardware. This is discussed in another QA on this site.

There wasn't much point in doing it, as it would have been several months of flight for a very brief approach to Venus, in which the crew couldn't do much that a robot couldn't do much more cheaply and safely.

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    $\begingroup$ @Uwe it's all here ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790072165.pdf Looks like there was a crewed volume at the top of the 3rd stage where the LM went on lunar missions. The CSM turned around and docked with that volume. $\endgroup$ Commented Feb 13, 2020 at 23:46
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    $\begingroup$ @OrganicMarble Thanks for the Pdf. So an extra habitat and solar cells should be used. $\endgroup$
    – Uwe
    Commented Feb 13, 2020 at 23:52
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    $\begingroup$ Not just the "adapter" volume, but the entire volume of the S-IVB hydrogen tank, after the TVI, would be available. $\endgroup$ Commented Feb 13, 2020 at 23:53
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    $\begingroup$ How about those projects to study the possibility of a manned mission to an asteroid ? "The goal is to capture an asteroid and bring it closer to Earth so that a manned mission can explore the space rock by 2025 — a major U.S. spaceflight goal set by Obama in 2010" Didnt they never reach a formal level of proposal or something? (I know it was cancelled, but we are talking about plans) space.com/20605-nasa-budget-asteroid-lasso-2014.html $\endgroup$
    – Pablo
    Commented Feb 14, 2020 at 13:59
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    $\begingroup$ @RussellBorogove Just make sure you vent it properly. 🤣 $\endgroup$
    – ceejayoz
    Commented Feb 14, 2020 at 15:52

Before cancelation of Constellation program in 2009 one of planned missions was manned asteroid landing and return. The same Orion spacecraft and Altair lander would be used as for the Moon.


Also manned landing on Phobos qualifies, I think. It should be easier than landing on Mars surface (with return, of course). There is no atmospheric entry problem. Also Phobos-landing craft does not need a lot of propellant/several stages for return.



I am not sure if this reaches the level you considered of "plans" but NASA had the HOPE (Human Outer Planets Exploration) studies, which involved flying a beautiful nuclear-powered ship to Callisto.



Yes, there have been and are multiple crewed mission concepts to celestial bodies other than the Moon and Mars, but they aren't covered by the media that much.

As stated in another answer, a Venus flyby in the Apollo spacecraft and Saturn V's third stage was a concept for the 1970s, but never realized. It was part of the Apollo Applications program to which SkyLab and the Apollo Soyuz Test Project belonged.

Around the turn of the millenium the concept came up of a manned mission to Callisto and establishing an outpost there, called HOPE, as stated in another answer. Callisto is the outermost Galilean moon of Jupiter and thus the only one where humans can remain permanently (with current technology) because it is far enough from Jupiter and thus its dangerous radiation. Callisto is a bit smaller than Mercury and an ice moon which may harbor life under its surface where a subsurface ocean is suspected to exist.

Current concepts for missions to celestial bodies other than the Moon and Mars include the High Altitude Venus Operational Concept HAVOC which is a plan to enter the atmosphere of Venus where the spacecraft would become an airship and the crew would float about 33 miles above Venus' surface on the equator. It would float in a speed that a day on Venus would be about 24 hours for the crew. At 33 miles altitude the atmospheric pressure of Venus is like Earth's surface pressure and the temperatures are around 50 degrees Celsius like on Earth in a hot summer. Astronauts wouldn't even need a pressurized suit if outside.

Then there are plans for a manned mission to an unspecified near-Earth asteroid with the Orion spacecraft that is planned to return astronauts to the Moon in 2024. However these plans are rather on hold because the lunar missions have priority now. Formerly it was planned that an asteroid would be trapped into lunar orbit and a crew would be sent to it. Note however that near-Earth asteroids are tiny and have little mass and gravity. You can't call that a "landing" but rather a tightening to them since you'd be in microgravity.

Well, and while there are no concrete concepts, many people think steps beyond: manned missions to Mercury (either its night side or a crater of eternal darkness), missions to main belt objects, to Europa, to Ganymede and to Saturn's moon Titan.

  • $\begingroup$ Welcome to Space! Nice answer. If you have quotes or links to your sources of information, that would be helpful. $\endgroup$
    – DrSheldon
    Commented Mar 21, 2020 at 21:36
  • $\begingroup$ @DrSheldon Thank you. HAVOC is already linked in my answer. For concepts of flights to Europa and Callisto see the WP page "Colonization of the outer Solar System" on Europa and Callisto as well as Callisto#Potential colonisation. You can google for "Objective Europa" a proposal to send someone to Europa forever. The Manned Venus flyby has its own WP article. $\endgroup$
    – user35272
    Commented Mar 22, 2020 at 6:24

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