water - and lots of it - confirmed on Mercury

[Blackpuddin]

Point the rockets in the other direction lads.
http://www.bbc.co.uk/news/science-environment-2055...

[TheHeretic]

A bit toasty. The 'black stuff', any idea what it is?

[dudleybloke]

he died years ago.

[Eric Mc]

Water, water everywhere - but not a drop to drink.

A very interesting find though.

[MartG]

It does mean that if we ever want to send a sample return mission to Mercury ( manned or unmanned ) then there is a ready source of fuel for the return trip

[Simpo Two]

MartG said:

It does mean that if we ever want to send a sample return mission to Mercury ( manned or unmanned ) then there is a ready source of fuel for the return trip

How is it that we can use water for energy in spaceships but not on Earth?

[TheHeretic]

Simpo Two said:

How is it that we can use water for energy in spaceships but not on Earth?

We can. The issue is normally have to take all the fuel we need for the entire trip. If we can manufacture fuel 'when we get there' then we could halve the weight requirement, ( or whatever... Power a station, make oxygen, and soon).

[anonymous-user]

the press love the sign of 'water = life' statement.

water was on earth for billions of years with no life..

maybe some amino acids there.

[MartG]

Simpo Two said:

MartG said:

It does mean that if we ever want to send a sample return mission to Mercury ( manned or unmanned ) then there is a ready source of fuel for the return trip

How is it that we can use water for energy in spaceships but not on Earth?

Water in itself doesn't provide any energy, but you can either electrolyse it into hydrogen and oxygen to use as rocket fuel & oxidiser, using either solar power ( lots of that at Mercury ) or nuclear to provide the electricity for electrolysis, or you can just use the water in a nuclear rocket where the nuclear energy turns the water into steam.

Either way the energy comes from somewhere other than the water, the water is just a hnady source of reaction mass.

[TheHeretic]

Bedazzled said:

Messenger used gravitational slingshots to reduce the delta-V from 13km/s to about 2.3km/s (600kg of fuel instead of 3500kg). How does that compare to the weight of your fuel manufacturing equipment...?

Might be relevant for a manned mission, as they couldn't survive a 6 year trip waiting for gravitational assists, but the issue is the fuel required to get there, not back. Mercury has a much lower escape velocity and you can use aero-braking on a return trip.

The question was about using water for fuel on mercury, but not on earth. We can.

[Eric Mc]

Bedazzled said:

TheHeretic said:

We can. The issue is normally have to take all the fuel we need for the entire trip. If we can manufacture fuel 'when we get there' then we could halve the weight requirement, ( or whatever... Power a station, make oxygen, and soon).

Messenger used gravitational slingshots to reduce the delta-V from 13km/s to about 2.3km/s (600kg of fuel instead of 3500kg). How does that compare to the weight of your fuel manufacturing equipment...?

Might be relevant for a manned mission, as they couldn't survive a 6 year trip waiting for gravitational assists, but the issue is the fuel required to get there, not back. Mercury has a much lower escape velocity and you can use aero-braking on a return trip.

Mercury is a very hard place to get to by spacecraft. Probes launched off earth have to kill a massive amount of orbital energy so they can start falling inwards towards the planet. Messenger made it easier for itself by using Venus as a gravitaional braking mechnism. I think it did three flybys of Mercury and loops around Venus before it had killed off enough of its velocity to allow it to enter orbit around Mercury.

Getting stuff off the surface of Mercury would be relatively easy, as its gravitational pull is low (lower than Mars) but geting the payload all the way out to earth orbit would require a huge amount of energy i.e. a big rocket as the spacecraft needs to climb "uphill" out of the sun's gravity well.

[Simpo Two]

Eric Mc said:

but geting the payload all the way out to earth orbit would require a huge amount of energy i.e. a big rocket as the spacecraft needs to climb "uphill" out of the sun's gravity well.

Solar yacht? The sun is nice and close and you're going away from it...

[Eric Mc]

Bedazzled said:

Eric Mc said:

Getting stuff off the surface of Mercury would be relatively easy, as its gravitational pull is low (lower than Mars) but geting the payload all the way out to earth orbit would require a huge amount of energy i.e. a big rocket as the spacecraft needs to climb "uphill" out of the sun's gravity well.

Yes I agree, but it requires a lot less energy than getting there, that's my point. You're shifting less mass, getting off the surface of Mercury is easy and critically you can use the Earth's atmosphere to slow for re-entry. Plus you've got to get all that fuel making equipment to Mercury, and slow it down when you get there (no aero-braking).

Even you took a big empty fuel tank there it's in the wrong place to get anywhere else. Sure if you find something to mine on Mercury it could be interesting but that's the stuff of good sci-fi.

With enough incentive and motivation, anything is possible.

[Daxed]

The Spruce goose said:

water was on earth for billions of years with no life..

No it wasn't

Whilst there is still a lot of argument as to when in our planets history it cooled sufficiently to allow the water to condense out of the atmosphere and to form the oceans, emergent life has been pegged down pretty well. Discussions regarding life starting before the end of the LHB aside, it seems that as soon as conditions allowed, life started and flourished, this speed being one of the main factors in the argument that life is not a rare event.

[Mojocvh]

The Spruce goose said:

the press love the sign of 'water = life' statement.

water was on earth for billions of years with no life..

maybe some amino acids there.

then along came a comet..........

[TheHeretic]

Mojocvh said:

then along came a comet..........

And promptly sold electronic tat, with next to no service.

[rhinochopig]

Bedazzled said:

TheHeretic said:

We can. The issue is normally have to take all the fuel we need for the entire trip. If we can manufacture fuel 'when we get there' then we could halve the weight requirement, ( or whatever... Power a station, make oxygen, and soon).

Messenger used gravitational slingshots to reduce the delta-V from 13km/s to about 2.3km/s (600kg of fuel instead of 3500kg). How does that compare to the weight of your fuel manufacturing equipment...?

Might be relevant for a manned mission, as they couldn't survive a 6 year trip waiting for gravitational assists, but the issue is the fuel required to get there, not back. Mercury has a much lower escape velocity and you can use aero-braking on a return trip.

The kit probably wouldn't be that heavy. An RTGs aren't THAT heavy and the electrolysis kit is scalable from grams to tonnes; depends on how much and how fast you want to crack the water.

[Hooli]

TheHeretic said:

Mojocvh said:

then along came a comet..........

And promptly sold electronic tat, with next to no service.

rhinochopig said:

Bedazzled said:

TheHeretic said:

We can. The issue is normally have to take all the fuel we need for the entire trip. If we can manufacture fuel 'when we get there' then we could halve the weight requirement, ( or whatever... Power a station, make oxygen, and soon).

Messenger used gravitational slingshots to reduce the delta-V from 13km/s to about 2.3km/s (600kg of fuel instead of 3500kg). How does that compare to the weight of your fuel manufacturing equipment...?

Might be relevant for a manned mission, as they couldn't survive a 6 year trip waiting for gravitational assists, but the issue is the fuel required to get there, not back. Mercury has a much lower escape velocity and you can use aero-braking on a return trip.

The kit probably wouldn't be that heavy. An RTGs aren't THAT heavy and the electrolysis kit is scalable from grams to tonnes; depends on how much and how fast you want to crack the water.

Why crack it? Wouldn't a nuke powered ion drive using the water as reaction material be more sensible? Or have I been reading too much sci-fi?