How feasible is a manned mission to Ceres?

[Travis]

Going to Mars gets all the attention but what if we wanted to do a manned mission to Ceres? Just how hard would that be? It would seem to me that it would be a good way to test out a lot of the equipment for an eventual Mars mission but on a destination that would be much easier to land on. Also it would still be potentially pretty cool. Maybe a kind of waypost could be setup there. Something that could serve as potential safe harbor should a mission to Jupiter's moons go awry.

 

[godless dave]

I don't know about landing on but it would certainly be easier to lift off from.

I think otherwise the technical challenges would be pretty much identical as a manned mission to Mars. Unfortunately, it probably wouldn't capture the imagination of the general public as much as a mission to Mars, and that drives a lot of decision making for space programs.

Maybe Dawn will find something interesting enough on Ceres to make a manned mission a priority.

 

[CynicalSkeptic]

Maybe a kind of waypost could be setup there. Something that could serve as potential safe harbor should a mission to Jupiter's moons go awry.

How useful would that be? How often do the orbits of Earth, Ceres and Jupiter line up where Ceres would be useful?

 

[Jim_MDP]

Something that could serve as potential safe harbor should a mission to Jupiter's moons go awry.

How reasonable is it that we will ever be able to maintain a habitat within the magnetosphere/radiation field of Jupiter?

 

[azzthom]

Ceres is much, much further away than Mars. Mars orbits the sun at roughly 1.52 AU, while Ceres is at roughly 2.77 AU. Obviously, the distance between Earth and the two bodies depends on relative orbital positions. However, it should be clear that Mars closest approach and mean distance from Earth are much closer than Ceres. This doesn't mean that humans can't/won't one day travel to Ceres. It's just unlikely (IMHO) that such a trip would be 'training' for a Mars mission. I think it's more likely to be the other way around.

And we are very interested in Ceres. NASA's Dawn mission will visit Ceres early next year and has already visited Vesta. This link has some details:-http://dawn.jpl.nasa.gov/

 

[theprestige]

Going to Mars gets all the attention but what if we wanted to do a manned mission to Ceres?

Why would we want to?

For science, of course, but at present an automated probe could probably do 1/10 the science at 1/100 the cost and 0/100 the risk of a human mission. So even if we did un-ass the budget for a science mission to Ceres, a probot would be a much better investment of those funds. (ETA: E.g., the Dawn mission. Thanks, azzthom!)

Just how hard would that be? It would seem to me that it would be a good way to test out a lot of the equipment for an eventual Mars mission

Ceres is further away than Mars. If you don't trust your equipment to take you to Mars, then you should be testing in low Earth orbit, a mere stone's throw from the best safe harbor we have anywhere in the solar system.

And if you do trust your equipment to take you to Mars, going to Mars is no more risky than going to Ceres, and is a much better way to spend your Mars mission budget.

but on a destination that would be much easier to land on.

Which is irrelevant to a Mars mission, since landing on Ceres can't support that mission.

Also it would still be potentially pretty cool.

On this point you have my most emphatic agreement. It's my prediction that within the next two centuries, wealthy amateurs will find that technological advances have put hobby space travel within their reach. They will embark on their own missions to Ceres and other "potentially pretty cool" destinations, not for science, but for adventure. Think James Cameron, not Neil Armstrong.

Ironically, the same technological advances that will make adventure travel accessible to a gradually-increasing portion of the general public, will continue to make automated missions the more cost-beneficial solution for science missions.

Maybe a kind of waypost could be setup there. Something that could serve as potential safe harbor should a mission to Jupiter's moons go awry.

The solar system is really big. A lot bigger than you think. It'd be like maintaining a waypost in the Aleutians, to serve as a potential safe harbor should a mission to Antarctica go awry.

Any mission to Jupiter that could survive long enough to reach Ceres could probably survive long enough to reach Earth, which is a much better safe haven.

Any other mission would be better served by a rescue mission launched to rescue them on a trajectory selected for that specific purpose, than by hoping that Ceres would happen to be in conjunction at the right time.

The other option would be to only do missions to Jupiter when Ceres is in conjunction, and also do missions to Ceres just to keep it ready for Jupiter missions. I don't think it's worth it.

Bottom line: A manned mission to Ceres is feasible today, if we really wanted to, but it's probably not something we'd want to do for any of the reasons given other than "potentially pretty cool". Which is a pretty good reason, but not yet good enough to make it happen at today's prices.

 

[Mark6]

On this point you have my most emphatic agreement. It's my prediction that within the next two centuries, wealthy amateurs will find that technological advances have put hobby space travel within their reach. They will embark on their own missions to Ceres and other "potentially pretty cool" destinations, not for science, but for adventure. Think James Cameron, not Neil Armstrong.

Several years ago on a different forum someone asked "When will be a manned mission to Pluto?" This is what I wrote:

I do not believe there will ever be a manned mission to Pluto. Which does not imply humans -- or our genetically modified post-human descendants, -- will never go there. But they will only do so when the Solar System is such an easy place to get around that visiting a place no one had visited yet is more of a lark than a mission. Think of the following analogy:

There are many, many little hills, streams and valleys in American and Canadian national parks no human being had walked on yet -- although all of them had almost certainly been photographed from air and mapped. When a forest ranger or an enterprising hiker sets off for one of such hills, would you call it a "mission"? No, it is just something moderately challenging that outdoorsy types do on a lark when they have a few days or weeks free.

Some day somebody will visit Pluto, Sedna, and every other KBO -- when the effort involved is no greater than hiking through Yellowstone* is today.

*Far from the marked trails, that is

 

[Roboramma]

There are many, many little hills, streams and valleys in American and Canadian national parks no human being had walked on yet

I find that highly implausible.

 

[Travis]

Well, correct me if I'm wrong, but isn't most of the issue with Mars getting through the atmosphere for the landing?

Ceres has almost no atmosphere. So shouldn't landing there be much easier?

 

[theprestige]

Well, correct me if I'm wrong, but isn't most of the issue with Mars getting through the atmosphere for the landing?

Think of it more as one of the unique problems of sending things to Mars

Ceres has almost no atmosphere. So shouldn't landing there be much easier?

Well, yes, but by the same token it does nothing to solve the unique problems of sending things to Mars.

If your goal is to land things on Mars, landing things on Ceres is a waste of time and money.

 

[Roboramma]

Well, correct me if I'm wrong, but isn't most of the issue with Mars getting through the atmosphere for the landing?

Ceres has almost no atmosphere. So shouldn't landing there be much easier?

I agree about the landing, although I'm not sure about the composition of Ceres, which may make a difference. If it's solid like the moon, then a landing similar to the landing on the moon should be feasible.

That's far from the only issue, though. Keeping people alive for the length of time necessary to get to Ceres, given the radiation, the fact that there's no chance of resupply or rescue part way through the mission, etc. makes for a pretty serious problem.

How long would a manned flight take to arrive at Ceres? The Dawn probe has an almost 8 year journey:

http://en.wikipedia.org/wiki/Dawn_(spacecraft)

Dawn is a space probe launched by NASA on September 27, 2007, to study the two most massive objects of the asteroid belt – the protoplanet Vesta and the dwarf planet Ceres. Currently en route to Ceres and is expected to arrive in February 2015

Mind you, it arrived at Vesta in 2011, only four years after launch, so perhaps if it was going to Ceres directly that would have been a more likely timeline.

It is also uses an ion drive propulsion system, which may lead (I don't know) to a longer flight time that conventional rockets.

Still, even 2 years is a long time to be in a tin can exposed to solar radiation, with only the supplies you can carry with you (and whose mass you have to factor in to the rocket equation...)

 

[Cuddles]

Well, correct me if I'm wrong, but isn't most of the issue with Mars getting through the atmosphere for the landing?

Ceres has almost no atmosphere. So shouldn't landing there be much easier?

Yes and no. The problem with Mars is that its atmosphere is sort of in the middle. It's too thin to land with aerobraking and parachutes as on Earth, but thick enough to make it tricky to land using rockets - you basically end up trying to fly through very strong and hot winds at supersonic speeds. So Ceres would be pointless. We already know how to land somewhere without an atmosphere, so it wouldn't teach us anything on that point. If you want practise landing somewhere with no atmosphere, the Moon is a lot closer.

On the other hand, those saying that Ceres is harder to get to because it's further away aren't actually entirely accurate. This page gives various calculations for getting around the solar system using different transfer orbits. Using Hohmann transfer orbits (second table), getting to Mars needs a delta-v of 16.5 km/s, while getting to Ceres needs a delta-v of 17.2 km/s. In the first table a variety of different possible (although all simplified from what would actually happen) return trips are looked at, one of which actually has a significantly lower delta-v for getting to Ceres compared to Mars.

On the gripping hand, getting to Ceres would certainly take significantly longer. So while the delta-v required may not be much more, a manned trip would need to carry significantly more mass, which means a lot more fuel to produce that delta-v.

Maybe a kind of waypost could be setup there. Something that could serve as potential safe harbor should a mission to Jupiter's moons go awry.

If anything, theprestige underestimates the problem with this. You're dealing with journey times of several months as an absolute minimum, using precisely defined transfer windows that are only open at certain very specific times. If you don't manage to hit one, you can end up needing hundreds or even thousands of times higher delta-v to get somewhere. If something goes wrong, you can't simply point your rocket somewhere closer.

In addition, have a look at the kind of problems space missions tend to have. Space is not a friendly place. If something goes wrong enough that you can't get where you're aiming, the chances of it not being so badly wrong that you can still spend several months getting somewhere else are extremely low.

 

[Travis]

Okay, so with Ceres the issue is the long trip time. But if we were able to surmount that issue actually landing on it should be quite simple.

Would it not make sense then that a mission to Ceres could be a good practice run for a mission to Jupiter? You could work out the bugs of the long journey but not have to deal with a difficult landing when you got there.

 

[Gawdzilla Sama]

How reasonable is it that we will ever be able to maintain a habitat within the magnetosphere/radiation field of Jupiter?

Under Europa's ice it wouldn't be that much of a problem, I think.

 

[Jim_MDP]

Under Europa's ice it wouldn't be that much of a problem, I think.

No good... the neighbors there value their privacy, and they're pretty arrogant about it.

 

[Piscivore]

Ironically, the same technological advances that will make adventure travel accessible to a gradually-increasing portion of the general public, will continue to make automated missions the more cost-beneficial solution for science missions.

You know what that mean--eventually we'll have rich douchebags kicking over planetary rovers for ***** and giggles.

 

[Damien Evans]

Well, correct me if I'm wrong, but isn't most of the issue with Mars getting through the atmosphere for the landing?

Ceres has almost no atmosphere. So shouldn't landing there be much easier?

Ceres is harder to get to (being further away) and Mars has almost no atmosphere.
http://en.wikipedia.org/wiki/Atmosphere_of_Mars

 

[Damien Evans]

Okay, so with Ceres the issue is the long trip time. But if we were able to surmount that issue actually landing on it should be quite simple.

Would it not make sense then that a mission to Ceres could be a good practice run for a mission to Jupiter? You could work out the bugs of the long journey but not have to deal with a difficult landing when you got there.

No, because with current or near current levels of technology no manned mission to Jupiter or the Galilean Moons would ever be considered by a sane person. The levels of radiation are simply way too high.

 

[Travis]

No, because with current or near current levels of technology no manned mission to Jupiter or the Galilean Moons would ever be considered by a sane person. The levels of radiation are simply way too high.

Okay, but what about a hundred years from now?

I would think that at some point humans will want to go to Jupiter.

 

[Hellbound]

No, because with current or near current levels of technology no manned mission to Jupiter or the Galilean Moons would ever be considered by a sane person.

I see. So you're advocating for training lunatics as astronauts?

I like it...