Ceres vs Mars

Tom Kalbfus · 2015-04-28 12:52:40

Ceres

Mars
Which is easier to land astronauts on?
Which has more water?
Could we grow plants on Ceres? How about Mars?
Mars Direct
Ceres Direct
What is the difference?
Could rocket fuel be produced on Ceres?

Seems to me, we only recently got to know Ceres as a world as opposed to a dot in the sky, how does this new perspective affect things? Could we fund a manned mission to Ceres at the same cost as a Mars mission. I also note that there are more frequent launch windows to Ceres than to Mars, as Earth catches up to Ceres and aligns itself more often.

Tom Kalbfus · 2015-04-28 12:58:59

Here's an article I picked up:

Manned Mission to Largest Known Asteroid Designed

Sending people to Ceres is no harder than sending them to Mars, study says.

By Charles Q. Choi, National Geographic
73572.adapt.768.2.jpg
Ceres is shown in relation to Vesta, Earth's Moon, Mercury and Mars. Image credit: NASA/JPL-Caltech/UCLA

Ceres is shown in relation to Vesta, Earth's moon, Mercury, and Mars in an illustration.

Photograph by NASA/JPL-Caltech/UCLA

Rocket scientists who have plotted a course for a human mission to the largest known asteroid, Ceres, say that such a voyage may not be much more challenging than sending people to Mars, according to a new study.

Research investigating human missions to asteroids blasted off in 2010, when President Obama proposed a human mission to an asteroid by 2025. NASA's Asteroid Initiative plans to use a robotic spacecraft to tow an asteroid to a stable orbit just beyond the moon, which would enable astronauts to visit the space rock as soon as 2021.

However, "we wanted to look beyond the small asteroid that President Obama's plan wants to send people to," said aerospace engineer James Longuski of Purdue University in Indiana. "Let's take a bigger step to the biggest asteroid."

Ceres was the first asteroid discovered, and is roughly 605 miles (975 kilometers) wide, or as big across as Texas. This makes it the largest asteroid in the asteroid belt between Mars and Jupiter—it accounts for more than a third of the belt's mass.

"It's so large, it has enough of a gravitational field to pull itself into a round shape, unlike most other asteroids, which just look like potatoes and funny-shaped rocks," Longuski said.

Ceres is also the smallest and closest dwarf planet at about 257 million miles (415 million kilometers) from the sun, and is the only one in the inner reaches of the solar system. NASA's Dawn spacecraft is scheduled to reach Ceres in 2015. (Related: "NASA's Dawn Spacecraft to Reach Asteroid This Weekend.")

Intriguingly, Ceres may have vast amounts of frozen water beneath its crust—if it was composed of 25 percent water, it would have more water than all the fresh water on Earth. Some researchers even think Ceres may have an ocean of liquid water under its surface, potentially making it of interest to scientists looking for signs of extraterrestrial life, since there is life virtually wherever there is liquid water on Earth.

"There's also a lot we could learn about the birth of the solar system from Ceres, since it's essentially a large leftover from the solar system's formation," said aerospace engineer Frank Laipert, also of Purdue University. "And a human could be a lot more effective as a scientist on Ceres than a robotic probe."

Last edited by Tom Kalbfus (2015-04-28 13:02:00)

GW Johnson · 2015-04-28 15:03:27

Once you're there, landing should be similar to the lunar landings, except easier, because the gravity is weaker, making the delta-vees lower.

Getting there will take longer, just because it is further out. You will have to solve the long-term life-support, radiation protection, and artificial gravity problems. That trip has 1-way voyages over a year and half long, not 6-9 months like Mars.

But, given solutions for those 3 areas, the same basic technology that could take us to Mars could take us to Ceres. Or to any other Main Belt body. Or Venus (no landing there!). Or Mercury (the lander problem is a bit tough at Mercury, much stronger gravity and delta-vee requirements than the moon).

I would think that any surface habitation or greenhouse stuff would look an awful lot like what we would have to build on the moon. There's no radiation protection from an atmosphere, or surface water or gases to utilize, as there are at Mars. Any water is way deep inside. Not the sort of thing you can reach with a shovel or a hand drill.

There hasn't been time yet for anything about Ceres to capture the public's imagination the way Mars has for centuries. A part of that is how similar Mars seems to Earth, in some ways. That might start to change once that probe gets to the business of exploring it from orbit. Yet, Ceres more-or-less looks like the moon. We'll see.

GW

Last edited by GW Johnson (2015-04-28 15:08:17)

Tom Kalbfus · 2015-04-29 05:58:39

The surface looks less interesting than the Moon, because all it is, is a bunch of craters, the Moon at least has mares, Ceres does not. I'm not sure what those white spots are, they could be frozen water, if so, they might be used by a surface installation for both water and as a source for return rocket fuel. Astronauts would probably move about the surface of Ceres by jumping with reaction control jets to make sure they land on their feet.

GW Johnson · 2015-04-29 11:45:31

If there's any surface-accessible ice, those weird bright spots are where it would be. The odds seem to favor underground ice uncovered by meteor strikes. But, who yet knows?

20-20 hindsight says we should have added landers to the Dawn probe.

GW

SpaceNut · 2015-04-29 19:05:50

Well when most things Nasa has seem to reach the end days they usually crash it into the body the study the impact plume.

I agree that the big items are the same for Mars but being that much farther away from the sun almost mean nuclear power of some sort as the primary energy source with solar as the secondary.

Definetly would want to burrow into the draft planet to create a permanant base and to protect the crew with the materials being a bonus.

Tom Kalbfus · 2015-04-30 08:52:11

Well the properties of Ceres are found here: http://en.wikipedia.org/wiki/Ceres_(dwarf_planet)
It has a 9-hour day, and a 3 degree axial tilt. The orbit varies between 2.5 to 3 au, That means we need mirrors of 6.25 to 9 times the light gathering area if you want to create Earth normal illumination. the surface gravity is 0.029 g and more importantly the escape velocity is 0.51 km/s, That means if you had 51 seconds of 1 g acceleration, you'd just about escape Ceres. This seems to indicate that if you built the interplanetary vessel right, you wouldn't need a surface lander. You just land the mother ship on the surface of the planet. Also if the interplanetary drive was capable of accelerating at 0.05 g it could also be used for takeoffs and landings. If the structure can survive that kind of acceleration, you probably just need to add landing legs and it can be used as a lander.

GW Johnson · 2015-05-01 16:27:57

Until Dawn has found out whatever it can at Ceres, I think it is way premature to consider sending men to do anything at Ceres. In contrast, we know quite a lot now, about Mars. So that's where we send crews, where the unknowns are less threatening. That is, as long as you intend they come home healthy and alive.

That being said, Tom is exactly right: at 2.9% gee, you can (and should) land the whole bloody ship. Provided it is not too fragile a design. No lander needed. That's true for all the "asteroids", BTW, especially since Ceres is the largest of them.

GW
"There's nothing as expensive as a dead crew"

louis · 2015-05-02 04:50:18

I agree Ceres is fascinating and should perhaps be destination no. 2 after Mars. Presumably at times it will be pretty "close" to Mars.

Tom Kalbfus wrote:

http://upload.wikimedia.org/wikipedia/c … 150414.jpg
Ceres
http://news.brown.edu/files/article_images/Mars1_0.jpg
Mars
Which is easier to land astronauts on?
Which has more water?
Could we grow plants on Ceres? How about Mars?
Mars Direct
Ceres Direct
What is the difference?
Could rocket fuel be produced on Ceres?
Seems to me, we only recently got to know Ceres as a world as opposed to a dot in the sky, how does this new perspective affect things? Could we fund a manned mission to Ceres at the same cost as a Mars mission. I also note that there are more frequent launch windows to Ceres than to Mars, as Earth catches up to Ceres and aligns itself more often.

Tom Kalbfus · 2015-05-02 06:00:44

One thing is almost certain. Ceres has more water than Mars! In fact its name is highly appropriate, Ceres was the Roman goddess of agriculture, we can most certainly do agriculture on Ceres, it has all the elements that are needed, and some mirrors to focus sunlight on some greenhouses would do the trick. I think plants will grow in 0.029 gravity. You can probably grow some large juicy tomatoes without needing stakes to hold them up! Carbon dioxide can probably be found within Cere's crust as frozen dry ice near the poles.

SpaceNut · 2015-05-02 06:52:09

We know the long term and initial costs of a mission launched from Earth for destination Cere's, but what would they be for any mission launched from a Mars location once we are established? Could other types of missions be launched from this location such as unmanned outward as well to other destination?

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#1 2015-04-28 12:52:40

Ceres vs Mars

#2 2015-04-28 12:58:59

Re: Ceres vs Mars

#3 2015-04-28 15:03:27

Re: Ceres vs Mars

#4 2015-04-29 05:58:39

Re: Ceres vs Mars

#5 2015-04-29 11:45:31

Re: Ceres vs Mars

#6 2015-04-29 19:05:50

Re: Ceres vs Mars

#7 2015-04-30 08:52:11

Re: Ceres vs Mars

#8 2015-05-01 16:27:57

Re: Ceres vs Mars

#9 2015-05-02 04:50:18

Re: Ceres vs Mars

#10 2015-05-02 06:00:44

Re: Ceres vs Mars

#11 2015-05-02 06:52:09

Re: Ceres vs Mars

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