Time to Mars, rather shocking

[Camacha]

A change, yes, but you said what you would be doing in orbit, which I assumed meant after you braked.

Orbiting and braking are not mutually exclusive. And I think you are referring to vger's post.

[KASASpace]

Orbiting and braking are not mutually exclusive. And I think you are referring to vger's post.

you were replying to a post about aerobeaking, and while accelerating on orbit you will get G's, but not just IN ORBIT.

[Rakaydos]

Yeah...

about that....

You see, I got the multiply by 2 from an actual rocket scientist.

Tell him someone on the internet wants him to check his math- turnover happens halfway, and you're only at half speed, so it should take at LEAST 4 times as long for a zero-zero intercept as a direct flight.

[78stonewobble]

The first trip to mars would be a magnificient thing, but...

Well... I'd prefer rather slow cyclers moving buttloads of people and materials to and fro, because that would hopefully mean a permanently established precense there.

[Seret]

I thought of that, but I just wanted to show that even at ~0.3 m/s^2 (~1ft^2) you could get to Mars quick. I, being a space enthusiast, find this fact amazing and shocking.

Yes, but somewhat obvious. If you go faster, you get where you're going sooner.

[Sirrobert]

Yeah...

about that....

You see, I got the multiply by 2 from an actual rocket scientist.

Ofcourse you did.

Did he also tell you to use feet and miles?

Anyway, your 'example' is about as usefull as saying that, if we could go 10 times faster than light, we'd be able to get to Alpha Centauri in 0.437 year

[Camacha]

Well... I'd prefer rather slow cyclers moving buttloads of people and materials to and fro, because that would hopefully mean a permanently established precense there.

Yes, I feel the same. Excursions are nice, but we really need to start looking towards more permanent expansion. It is what we have done since before humans emerged from Africa, there is no reason to stop now. And a lot of reason to continue.

A big advantage of a more slow and steady approach is that ships will support life for extended periods of time, meaning that an emergency is less likely to cause huge problems as systems will probably be a lot more redundant.

[KASASpace]

Tell him someone on the internet wants him to check his math- turnover happens halfway, and you're only at half speed, so it should take at LEAST 4 times as long for a zero-zero intercept as a direct flight.

Sorry to say, but I'm quite sure that rocket scientists who have worked at NASA for 30 years know what they're doing.

[KASASpace]

The first trip to mars would be a magnificient thing, but...

Well... I'd prefer rather slow cyclers moving buttloads of people and materials to and fro, because that would hopefully mean a permanently established precense there.

This kind of thing would be for moving supplies to the colony beforehand for easier setup.

[KASASpace]

A big advantage of a more slow and steady approach is that ships will support life for extended periods of time, meaning that an emergency is less likely to cause huge problems as systems will probably be a lot more redundant.

Wow.

You do realize that that statement counters itself.

Less time in interplanetary space means less likely something will go wrong at that critical moment.......

[Camacha]

Wow.

You do realize that that statement counters itself.

I understand what you are trying to say, but it does not. I think it is most easily explained with an analogy. Fast ships are built to keep the crew alive for the journey and a little bit. Compare it to a sportscar. Not roomy, not comfortable, but it will get you there quick and with relative efficiency. Now, a larger slower ship means people really have to live in it and build their lives there. Compare it to a seafaring boat or a big camper/RV. You take a lot more with you, but that also means you have more stuff for an extended stay and your gear will be more redundant. Defects are not a big problem, because although there is more time for them to occur, you are a lot more prepared to deal with them. Just replace the lightbulb and carry on. Maybe you even have facilities to fabricate things yourself - seafaring ships often carry whole workshops.

If you arrive at your destination and your hotel turns out to be burned to the ground, you have a problem if you came by sportscar. Sleeping in the car is hardly possible and you did not have room to bring your tent. In a camper, you just sleep in the car and all will be well. It is almost as comfortable as sleeping in a hotel, as you brought your home with you. You were not merely surviving on board of your ship, you were living there.

[Rakaydos]

Sorry to say, but I'm quite sure that rocket scientists who have worked at NASA for 30 years know what they're doing.

Ask anyway, please. A calculus student's worst enemy is basic arithmatic- I can only inagine it becoming more dramattic as you rely more and more on automaton- its easy to understand if a simple error like this crept into it.

[KASASpace]

I understand what you are trying to say, but it does not. I think it is most easily explained with an analogy. Fast ships are built to keep the crew alive for the journey and a little bit. Compare it to a sportscar. Not roomy, not comfortable, but it will get you there quick and with relative efficiency. Now, a larger slower ship means people really have to live in it and build their lives there. Compare it to a seafaring boat or a big camper/RV. You take a lot more with you, but that also means you have more stuff for an extended stay and your gear will be more redundant. Defects are not a big problem, because although there is more time for them to occur, you are a lot more prepared to deal with them. Just replace the lightbulb and carry on. Maybe you even have facilities to fabricate things yourself - seafaring ships often carry whole workshops.

If you arrive at your destination and your hotel turns out to be burned to the ground, you have a problem if you came by sportscar. Sleeping in the car is hardly possible and you did not have room to bring your tent. In a camper, you just sleep in the car and all will be well. It is almost as comfortable as sleeping in a hotel, as you brought your home with you. You were not merely surviving on board of your ship, you were living there.

Did you read any of the purposes for this ship? Delivering cargo before the ship with crew arrives. No crew, so they can come in whichever ship they wish, and cause there is no crew, you want as little time as possible in interplanetary space, because you can't really afford to carry robot's to repair.

[LaydeeDem]

What's there to repair? You just said it's a cargo ship.

[Camacha]

Did you read any of the purposes for this ship?

We were talking about slow moving cilinders shipping people and materials back and forth.

you want as little time as possible in interplanetary space, because you can't really afford to carry robot's to repair.

The idea is that you either take a large amount of spares just in case, or you take production facilities with you to replace all those spares. If you do that right it will save money and weight, instead of adding it. Bringing manufacturing capabilites could and should be very cost effective.

With spaceflight there is no need to hurry - safe and steady are the things you want and that often boils down to taking things slow.

Edited March 13, 2014 by Camacha

[maccollo]

Did you read any of the purposes for this ship? Delivering cargo before the ship with crew arrives

That makes no sense at all. Bulk cargo is not transported in super sonic jets. It's done by cargo ships.

When we're talking bulk cargo you want to move as much as you can with as little effort as you can. You're talking about something that requires 360 km/s.

Using an ISP of 3000 that means the mass fraction has to be 1:200 000, which is impossible, even if it was was, you could move 150 000 times more cargo using an optimal transfer.

The only way this would make sense is if we had a something like a fusion engine with an ISP approaching 100 000.

you want as little time as possible in interplanetary space, because you can't really afford to carry robot's to repair.

Wat? We will have robots that outperform us in every regard long before we have some miracle fusion engine, and they will be cheap as chips in comparison.

[m4rt14n]

OP reported to mods for doing physics in imperial units.

Lol at imperial units

[KASASpace]

That makes no sense at all. Bulk cargo is not transported in super sonic jets. It's done by cargo ships.

When we're talking bulk cargo you want to move as much as you can with as little effort as you can. You're talking about something that requires 360 km/s.

Using an ISP of 3000 that means the mass fraction has to be 1:200 000, which is impossible, even if it was was, you could move 150 000 times more cargo using an optimal transfer.

The only way this would make sense is if we had a something like a fusion engine with an ISP approaching 100 000.

Wat? We will have robots that outperform us in every regard long before we have some miracle fusion engine, and they will be cheap as chips in comparison.

Are we forgetting one of the coolest and most effective modes of transport?

Two words:

Solar sail.

[SargeRho]

Too weak. Magsail ftw.

[KASASpace]

Too weak. Magsail ftw.

Too weak? Really? Did you hear about that probe that could accelerate for 100 days and get to Pluto within 5 years? No? Than look it up. Cosmos 1, I think.

[SargeRho]

Yes, too weak. A Z-Pinch Fusion, or Beam Confinement Fusion rocket could probably do that trip in less than 2 years. A magsail can do it faster than a solar sail, too. Protons have more momentum than Photons.

[andrewas]

Too weak? Really? Did you hear about that probe that could accelerate for 100 days and get to Pluto within 5 years? No? Than look it up. Cosmos 1, I think.

Nope. Read the article again, it takes 3 years to get up to speeds which could get you to pluto in five years - but thats not accounting for the drop in acceleration as the craft gets further from the sun.

[LaydeeDem]

If one aimed a rocket with no payload but fuel at mars it would get there pretty fast too.

[KASASpace]

Yes, too weak. A Z-Pinch Fusion, or Beam Confinement Fusion rocket could probably do that trip in less than 2 years. A magsail can do it faster than a solar sail, too. Protons have more momentum than Photons.

Okay, a BIG solar sail, kilometers in width and height.

How about that.

[KASASpace]

Nope. Read the article again, it takes 3 years to get up to speeds which could get you to pluto in five years - but thats not accounting for the drop in acceleration as the craft gets further from the sun.

Of course it would be scaled up to accelerate enough.