Elon Musk provides new details on his ‘mind blowing’ mission to Mars

Re:Elon Musk provides new details on his ‘mind blowing’ miss... by jrv on Saturday June 11, 2016 @09:56AM (#11883444)

I'm no expert at all, but three things come to mind:

- Mars has a (thin) atmosphere, mostly made up of CO2 -> good for plant growth. The Moon has none.

- Mars has gravity closer to Earth than the Moon.

- Mars has lots of water, while the moon has possibly just a little?

EDIT: found http://www.mars-one.com/faq/mission-to-mars/why-mars-and-not..., which cites similar and more reasons (although Mars One seems to be pretty much a scam).

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Re:Elon Musk provides new details on his ‘mind blowing’ miss... by bergie on Saturday June 11, 2016 @10:02AM (#11883466)

The Martian atmosphere also makes aerobraking possible, meaning spacecraft arriving there need less delta-V. A Dragon2 can land in Mars, but not on the Moon because of this.

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Re:Elon Musk provides new details on his ‘mind blowing’ miss... by exDM69 on Saturday June 11, 2016 @10:14AM (#11883504)

Aerobraking is a benefit but is the Dragon really unable to land on the moon? The moon has less gravity (about half) and the velocity difference should be much smaller for a lunar intercept than a Mars intercept.

Has anyone got numbers for this?

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Re:Elon Musk provides new details on his ‘mind blowing’ miss... by lmm on Saturday June 11, 2016 @10:20AM (#11883527)

Dragon doesn't have enough delta-V to land on the moon. The plan for a Mars landing is to use it as a lifting body to keep it above the ground for long enough to shed most of its velocity.

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Re:Elon Musk provides new details on his ‘mind blowing’ miss... by dalke on Saturday June 11, 2016 @11:10AM (#11883696)

I've read various statements which say that Dragon can land on the Moon, such as http://www.nbcnews.com/science/space/mars-ahead-spacex-unvei... :

> Musk has said a fully loaded Dragon could even be sent to make a touchdown on the moon or Mars

or https://www.nasaspaceflight.com/2016/04/spacex-debut-red-dra... :

> “With Dragon launched on a Falcon Heavy, it can go pretty much anywhere in the solar system, because that’s a heck of a big rocket,” he continued.

> “Dragon, with the heat shield, parachutes and propulsive landing capability, is able to land on a planet that has higher entry heating, like Mars. It can also land on the Moon, or potentially conduct a Europa mission.”

How does that fit with the statement "Dragon doesn't have enough delta-V to land on the moon"?

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Re:Elon Musk provides new details on his ‘mind blowing’ miss... by exDM69 on Saturday June 11, 2016 @10:24AM (#11883542)

Yes, GP said that already but I'm after the numbers here. How much delta-v the Dragon has? And what are the approximate requirements for Moon vs. Mars landing?

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Re:Elon Musk provides new details on his ‘mind blowing’ miss... by Symmetry on Saturday June 11, 2016 @10:50AM (#11883619)

The Dragon 2 has about 1.6 km/s. Apollo had 2.47 km/s to land and 2.22 km/s to take off. Oh, and it would take on the order of 4.5 km/s to take off from Mars and maybe a few hundred to land.

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Re:Elon Musk provides new details on his ‘mind blowing’ miss... by exDM69 on Saturday June 11, 2016 @11:56AM (#11883898)

Thanks! These numbers look reasonable to me. Can you provide a link to source (s)? I'd like to read some more...

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Re:Elon Musk provides new details on his ‘mind blowing’ miss... by robbiep on Saturday June 11, 2016 @10:48AM (#11883612)

'- Mars has gravity closer to the earth than the moon'

Depends on what you mean by close. 0.38 is closer to 16.7 than 1, but any improvement on that is important

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Re:Elon Musk provides new details on his ‘mind blowing’ miss... by Manabu-eo on Saturday June 11, 2016 @11:59AM (#11883912)

If you are talking about human health, it might be that any gravity bellow 0.8g is almost as bad for human health as microgravity. It could be that any gravity above 0.1g is as good as 1g for human health. We simply don't know the format of that curve. We have no data on it even on rodents (the ISS module for that was scrapped). We only know that 1g is good and microgravity is bad. And that very high g is bad too.

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