Mars by 2020?

Rubecula · 09-10-2017 3:46am

what does Sol 4766 mean? days (earth) days (mars) or days (sun???) ?

Capt'n Midnight · 09-10-2017 10:23pm

Rubecula wrote: »

what does Sol 4766 mean? days (earth) days (mars) or days (sun???) ?

A sol is a local day.

The ground crew for many of the Mars lander missions work on "Mars time" , special watches that run slow to match.

Fathom · 10-10-2017 1:13am

Rubecula wrote: »

what does Sol 4766 mean? days (earth) days (mars) or days (sun???) ?

"A Mars solar day has a mean period of 24 hours 39 minutes 35.244 seconds, and is customarily referred to as a "sol" in order to distinguish this from the roughly 3% shorter solar day on Earth."

Rubecula · 10-10-2017 1:43pm

so an extra fortnight in earth days?

Rubecula · 10-10-2017 3:48pm

Fathom · 12-10-2017 3:35pm

Large solar storm sparks global aurora on Mars.

Fathom · 13-10-2017 3:44pm

Mars Study Yields Clues to Possible Cradle of Life. a-view-of-a-portion-of-the-eridania-region-of-southern-mars.png?rect=0%2C106%2C1382%2C461&auto=format%2Ccompress&w=650

a-view-of-a-portion-of-the-eridania-region-of-southern-mars.png?rect=0%2C106%2C1382%2C461&auto=format%2Ccompress&w=650

Capt'n Midnight · 14-10-2017 12:17am

Fathom · 14-10-2017 3:27pm

Ion Thruster Sets World Record. Send Humans to Mars?

Fathom · 15-10-2017 3:54pm

SpaceX CEO Elon Musk gives major update on his plans to colonize Mars.

Fathom · 18-10-2017 4:12pm

Falcon 9 has completed 16 successful landings on Earth. Baby steps towards Mars landing by SpaceX?

Rubecula · 19-10-2017 5:16am

Fathom wrote: »

Falcon 9 has completed 16 successful landings on Earth. Baby steps towards Mars landing by SpaceX?

just spent a few hours watching documentaries like this, excellent stuff Fathom, thank you for posting.

Fathom · 20-10-2017 7:41pm

Rubecula wrote: »

just spent a few hours watching documentaries like this, excellent stuff Fathom, thank you for posting.

Feeling is mutual. Thank you for posting too!

Rubecula · 20-10-2017 8:24pm

Fathom · 21-10-2017 9:56pm

HD Documentary 2017 Interstellar Flight

Rubecula · 24-10-2017 1:56am

good post Fathom

Fathom · 25-10-2017 4:07am

Rubecula · 05-11-2017 5:51am

Fathom · 08-11-2017 4:54pm

Prospective SpaceX Mars rocket? Too small?

Rubecula · 09-11-2017 6:50am

not sure I could live in that without going mad for the time it would take to get to get anywhere, let alone Mars

Fathom · 09-11-2017 6:22pm

Mars and Earth's orbits are not perfectly circular. Time it takes to travel between them today varies from 6 to 8 months. SpaceX spaceship small space for journey?

Capt'n Midnight · 09-11-2017 10:46pm

Fathom wrote: »

Prospective SpaceX Mars rocket? Too small?

42 engines is a plumbing nightmare.

Ask the Russians about the N1 and it's 30 engines.

Rubecula · 10-11-2017 6:09am

Capt'n Midnight wrote: »

42 engines is a plumbing nightmare.

Ask the Russians about the N1 and it's 30 engines.

the rocket may be big enough, but you need somewhere for the crew that is big enough to live in.

Fathom · 10-11-2017 8:31pm

Capt'n Midnight wrote: »

42 engines is a plumbing nightmare. Ask the Russians about the N1 and it's 30 engines.

Still old tech thinking? Alternatives?

Rubecula wrote: »

the rocket may be big enough, but you need somewhere for the crew that is big enough to live in.

Roomy Star Trek?

Capt'n Midnight · 12-11-2017 11:59pm

Fathom wrote: »

Still old tech thinking? Alternatives?

Yes and No.

Yes, old tech.
If you've ever heard of single stage to orbit, remember that the original Russian Soyuz launch system was a stage and a half to orbit. Main engines tested just before launch and fired all the way up.

No, no alternatives
Soyuz has seen off many replacements and is now used by the USA for all manned flights, the Europeans for satellite launches and the Russians for both.

In theory there alternatives, the US has thrown away loads of them, I wouldn't be surprised if Soyuz outlives yet another US launch system.

Because we live at the bottom of a gravity well a rocket would have to provide 1g of acceleration just to stay still , this rules out any existing technology except chemical rockets.

The fuel pumps on the Saturn 5 rocket were fifty five thousand horsepower, each. Or 205 Megawatts in total. On take off the engines put out as much power as France, as in the entire French electricity network.

Most of the power and energy was used to accelerate the remaining fuel that was later used to accelerate what was left of the remaining fuel and so on

There two other ways to get to orbit.
The first is speed. Easy peasy. You just need to be going fast enough and in the right direct. If you use an external mechanism for power and thrust you can save a lot of mass.
If your craft had a frontal area of 1m squared then at sea level you'd need to push 1Kg of air out of your way for every meter per second you were travelling at. So figure out ten tonnes of, superheated by compression, air in the first second.

The other is to climb up a ladder. We don't quite have the material to make a space elevator. And the power transmission distance and strain on the cable limit the speed you can go up the elevator. At 100km/hr you'd climb past Everest in under 5 minutes but you wouldn't get to GEO until a fortnight later. Also the total mass climbing up or down would have to be counter balanced by a massive weight past GEO.

Rubecula · 13-11-2017 10:19am

No no no you have it all wrong :eek:

Have to go to medical appt. now be back later.

Rubecula · 13-11-2017 2:20pm

Capt'n Midnight wrote: »

Yes and No.

Yes, old tech.
If you've ever heard of single stage to orbit, remember that the original Russian Soyuz launch system was a stage and a half to orbit. Main engines tested just before launch and fired all the way up.

No, no alternatives
Soyuz has seen off many replacements and is now used by the USA for all manned flights, the Europeans for satellite launches and the Russians for both.

In theory there alternatives, the US has thrown away loads of them, I wouldn't be surprised if Soyuz outlives yet another US launch system.

Because we live at the bottom of a gravity well a rocket would have to provide 1g of acceleration just to stay still , this rules out any existing technology except chemical rockets.

The fuel pumps on the Saturn 5 rocket were fifty five thousand horsepower, each. Or 205 Megawatts in total. On take off the engines put out as much power as France, as in the entire French electricity network.

Most of the power and energy was used to accelerate the remaining fuel that was later used to accelerate what was left of the remaining fuel and so on

There two other ways to get to orbit.
The first is speed. Easy peasy. You just need to be going fast enough and in the right direct. If you use an external mechanism for power and thrust you can save a lot of mass.
If your craft had a frontal area of 1m squared then at sea level you'd need to push 1Kg of air out of your way for every meter per second you were travelling at. So figure out ten tonnes of, superheated by compression, air in the first second.

The other is to climb up a ladder. We don't quite have the material to make a space elevator. And the power transmission distance and strain on the cable limit the speed you can go up the elevator. At 100km/hr you'd climb past Everest in under 5 minutes but you wouldn't get to GEO until a fortnight later. Also the total mass climbing up or down would have to be counter balanced by a massive weight past GEO.

back again

Soyuz was not a rocket launch system, the rocket booster was never called Soyuz, Salyut or whatever.

Because we are at the bottom of a gravity well a rocket has to provide 1g of acceleration to stay in on place??????????? no this is so wrong, the Earth has a gravity of about 1g at sea level. we are already using 1g of force by pushing down on the planet. Notice I said about 1g at sea level. this is because gravity does vary.

this bit does not make a great deal of sense to me, dunno why but somehow it does not flow properly, sorry : "If your craft had a frontal area of 1m squared then at sea level you'd need to push 1Kg of air out of your way for every meter per second you were travelling at. So figure out ten tonnes of, superheated by compression, air in the first second"

finally your figures on the space elevator, areyou certain? I think accelerating for a fortnight would have you a bit further than GEO even at less than 1g.

Fathom · 13-11-2017 6:43pm

Once beyond Earth's atmosphere, how about photonic propulsion? System would use lasers to propel a giant sail. Claims to reach Mars in 3 days rather than months.

Capt'n Midnight · 13-11-2017 9:41pm

Rubecula wrote: »

Because we are at the bottom of a gravity well a rocket has to provide 1g of acceleration to stay in on place??????????? no this is so wrong, the Earth has a gravity of about 1g at sea level. we are already using 1g of force by pushing down on the planet. Notice I said about 1g at sea level. this is because gravity does vary.

A rocket that generates thrust equal to it's mass will accelerate at 1g in free space, but here on Earth it will just sit there.

So can't use ion drive or solar sails to get to orbit.

And yes gravity drops off as you climb out of the well , it also drops as you accelerate because , to dumb it down centrifugal force.

this bit does not make a great deal of sense to me, dunno why but somehow it does not flow properly, sorry : "If your craft had a frontal area of 1m squared then at sea level you'd need to push 1Kg of air out of your way for every meter per second you were travelling at. So figure out ten tonnes of, superheated by compression, air in the first second"

The atmosphere is kinda like having 10 meters of water above you.

If you accelerate horizontally then you have to go through more of it.
Say roughly 10Km/s to get to orbit , so 10,000 meters of air

finally your figures on the space elevator, areyou certain? I think accelerating for a fortnight would have you a bit further than GEO even at less than 1g.

Ah, but you aren't accelerating. If you were then you would need a humongous counterweight above GEO and stronger tethers.

Fathom · 20-11-2017 6:39pm

Capt'n Midnight wrote: »

A rocket that generates thrust equal to it's mass will accelerate at 1g in free space, but here on Earth it will just sit there. So can't use ion drive or solar sails to get to orbit.

Still Earth bound by old tech. When will this change? Any theoretical probabilities that might reach fruition someday?

Mars by 2020?

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