The Case For Going To Phobos Before Going To Mars

MarkWhittington writes: The current NASA thinking concerning the Journey to Mars program envisions a visit to the Martian moon Phobos in the early 2030s before attempting a landing on the Martian surface in the late 2030s, as Popular Mechanics noted. The idea of a practice run that takes astronauts almost but not quite to Mars is similar to what the space agency did during the 1960s Apollo program. Apollo 8 and Apollo 10 each orbited the moon but did not land on it before the Apollo 11 mission went all the way to the lunar surface, fulfilling President John. F. Kennedy's challenge.

Comments

Natural space station

[Maritz]

If we were inclined to go to Mars (which we don't appear to be) Phobos would be a natural choice because it's a ready-made space station. Probably mostly hollow, built-in radiation protection. You could probably pressurise some natural caverns in there.

But we won't do any of that, because we prefer aircraft carriers and strategic nukes.

Re:Natural space station

[taiwanjohn]

I saw Robert Zubrin talk at a recent conference (via YouTube) and he said the delta-V between Phobos's orbit and the orbits you'd want to use for landing on Mars is very costly, making it an unnecessary and wasteful detour on the way to our real destination. The only reason you'd go there would be to tele-robotically build your Mars base before you land, and Phobos would provide radiation shielding for that long process.

OTOH, building your base would go a lot quicker if done by astronauts on the surface, and radiation shielding wouldn't be that hard to improvise with Martian regolith. Granted, you would probably get less shielding that way than you would on Phobos, but you'd have far less effects from long-term microgravity too, so... pick your poison.

Zubrin's point is, if your long-term goal is to have a colony on Phobos, then go to Phobos. If your goal is a colony on Mars, just go there and do that.

Re: An interesting option

[Anonymous Coward]

Who said we can't? We should aim the Moon. It shouldn't be fully manned, an automated base which can sustain visitors like the ISS, would be enough as starters.
The Moon has smaller gravity than Earth, yet it has gravity, so people can live there for a long time without various problems, it makes sense to have a base there if we plan longer journeys in space. The Moon could have a fuel station and probably also an automated spaceship factory. If water / metal resources could be brought there from extra terrestrial sources, we would spare a lot of fuel by bringing them to a low gravity environment instead of Earth. It is cheaper than maintaining simulated gravity on a full space based assembly station (by rotation, i guess, pending invention of artificial gravitation).

Re: An interesting option

[Coisiche]

We can't build a sustainable habitat in Antarctica or in the middle of a desert

Can't or won't? I would have thought that it would be possible to create a habitat in either that would require nothing incoming. Not easy, but not impossible. It would just cost a fuck of a lot to build and would probably require a very large area (either above or below ground) to support just a few people.

Both locations, however, have the immeasurable benefit of being on a planet with a breathable atmosphere and getting the huge amount of resources required to set up this habitat to the location would not involve climbing a gravity well.

It's definitely a "won't" for anywhere on Earth and likely a "can't" for anywhere else in the solar system.

Phobos proposal is retarded...

[denzacar]

Also, a budget padding enthusiasts wet dream.

It suggests 3 (three) separate trips for what can be achieved by 1 (one). Namely, getting astronauts to Mars surface for a prolonged stay and an extensive scientific mission.

First, send astronauts to hop around on Phobos in 2033.
Then, send astronauts to land on Mars in 2039 - and fuck off back to Earth almost immediately.
Then, in 2043, send astronauts for a year-long stay on Mars.

Supposedly, (paper is paywalled) "each mission campaign would build on previous campaigns, leaving a legacy and new capabilities for those that follow."

Except the cost of all three missions is in getting to Mars orbit and back.
And if the last mission is supposed to last a whole year on Mars, a full DECADE after the first mission, and 4 years after the second one - they are NOT carrying ANY supplies or building ANY infrastructure on or near Mars surface.
For a simple reason that you can't rely on anything still being there in working order 10 years in the future.
Or 6. Or 4.
You can't even use the SAME FUCKING PEOPLE as they will be a decade older and maybe dead or maybe doing another job.
Astronauts have to eat too, you know.

Further, anything done on Phobos has fuck all to do with any following mission. They are not gonna build a base there or store supplies - it's a hop-around mission.
And should a second mission happen, only reason why not to stay there for a whole year is - SUPPLIES! Or the lack there of.
Which won't be there because... "Meh... not this time. We'll bring it the next time. Not right now. Later."

This is NOTHING like an Apollo missions to the Moon.
This is like swimming to America from Scotland, getting to Liberty Island, eating a sandwich brought with you, then swimming back home.
Then, 6 years later, do the same thing - only climbing out of the water in New York Harbor, sleeping over night in Central Park, eating another sandwich in the morning (again brought from back home) and swimming back to Europe.
THEN, 4 more years later, you take another swim across the ocean, only instead of taking a sandwich, this time you take a credit card and you spend a year living in USA.

Oh and yeah... Each trip there is a team of thousands of people and dozens of boats sailing right next to you and keeping you safe from the sharks and tigers (You don't know... maybe there are tigers along the way... better safe than sorry.), tweetering your progress online and whatnot.

Re:Phobos proposal is retarded...

[Anonymous Coward]

Except the cost of all three missions is in getting to Mars orbit and back.

Getting from low Earth orbit to Mars orbit and back costs you 9.4 km/s (ref). Adding a landing on Phobos while you're there costs you an extra 2.0 km/s. Adding a landing on Mars costs you an extra 11.0 km/s. Planets are annoyingly unwilling to let visitors go.

And remember, those delta-v costs aren't additive: they're exponential, with a constant of your exhaust velocity (~4.5 km/s). So the extra 9 km/s to touch down on Mars rather than Phobos makes your launch mass, and your cost, increase by a factor of exp(9/4.5) = 7.4. You could launch seven Phobos missions for the cost of one Mars mission.

In practice, it's not quite that bad: you save part of the cost at Mars by aerobraking, you leave your return vessel in orbit, you leave your gear on the surface, etc. But it's a big enough difference to show that your analogy is based on a serious misunderstanding of how space works.

Re: An interesting option

[MooseTick]

If the goal is to build a habitat in extreme cold conditions, I'm sure Alaska has plenty of places to build it. Before we likely spend trillions of dollars sending a body to mars, I'd like to see a self sustaining habitat on Earth last for at least 10 years. And have it be one that is the same size and contents as would be buildable off planet. And it would be even better if they were able to do more than just survive.

As I've said before, even if we totally trashed the earth, it would still likely be more habitable than the moon or mars or anywhere else we could go to. I suspect a post-nuked earth would be more human friendly than dwelling on another planet.