Arthur C. Clarke published his solar sail science fiction short story The Sunjammer way back in 1964.
Unfortunately, NASA cancelled the Solar Cruiser mission: https://www.planetary.org/space-missions/solar-cruiser
Unfortunately, NASA cancelled the Solar Cruiser mission: https://www.planetary.org/space-missions/solar-cruiser
Last edited:
Clarke was a clever guy. Right surprisingly often. Though it's the space elevator in Sri Lanka that really intrigued.
I notice ramscoops have fallen out of favour.
I prefer the idea of just reprogramming the universes metadata so that the ship is elsewhere...
It was a Bussard ramjet that powered the starship Leonora Christine, from Poul Anderson’s 1970 science fiction novel Tau Zero. No need to take your fuel with you, just scoop it up from the interstellar medium! https://en.wikipedia.org/wiki/Bussard_ramjet
Unfortunately, it's now thought that the density of interstellar hydrogen may not be great enough to feed a ramjet adequately. The ram would have to be so large that its drag would outweigh the propulsion.
It's about 2-3 hydrogen atoms/m^3 in interstellar pace, and about 1/4 of that in intergalactic space. Nowhere near enough unfortunately.
Sir Arthur was not the first person to come up with the idea of a "space elevator" or, more correctly, a "space funicular".
However, he was responsible for introducing the concept to a far larger audience in his book The Fountains of Paradise.
Unfortunately, due to the strength of Earth's gravity, the cable would have to be built of exotic materials with extreme tensile strengths.
However, a "lunar elevator" might actually be doable.
One could be attached to a space station at a Lagrange Point where the Moon and Earth’s gravity cancel out, so the station can remain stationary.
Since the Moon’s gravity is 1/6th that of Earth’s, the cable could be built using high-strength materials that are currently available.
But then the reduced gravity means other launch possibilities are available and still, probably, more easily implemented. Railgun catapult springs to mind. Fireball XL5 yaaaay.
Still can't help feeling that overall, ship assembly would be likely to be largely out of the steeper part of the gravity well if you're building anything that's hauling cargo or significant numbers of people.
Back to Mars. Are we at a point where Mars launches could be unmanned to start but have enough robot assembly to prepare buildings etc for when the meat sacks arrive?
Referring to a Mars space elevator, Arthur C. Clarke wrote:
"The planet which seems ideally suited for the space elevator is Mars, with only one third of Earth’s gravity. What is more, the outer satellite Deimos is only slightly above stationary orbit — in just the right position to provide a mass anchor! Moreover, it appears to be largely carbonaceous, so could supply the required construction material.
But there is one big problem — about ten million million tons — in connection with the Mars elevator, and that’s the inner moon, Phobos. Moving almost exactly in the equatorial plane, it would slice through the elevator at very frequent intervals. Phobos is much too big to tow away, and blowing it up would only make matters worse. I refer you to The Fountains of Paradise for one solution…"
Read his full analysis of the space elevator concept in his paper first published in 1981 on Advances in Earth Oriented Applied Space Technologies:
https://spaceref.com/newspace-and-t...r-key-to-the-universe-by-sir-arthur-c-clarke/
"The planet which seems ideally suited for the space elevator is Mars, with only one third of Earth’s gravity. What is more, the outer satellite Deimos is only slightly above stationary orbit — in just the right position to provide a mass anchor! Moreover, it appears to be largely carbonaceous, so could supply the required construction material.
But there is one big problem — about ten million million tons — in connection with the Mars elevator, and that’s the inner moon, Phobos. Moving almost exactly in the equatorial plane, it would slice through the elevator at very frequent intervals. Phobos is much too big to tow away, and blowing it up would only make matters worse. I refer you to The Fountains of Paradise for one solution…"
Read his full analysis of the space elevator concept in his paper first published in 1981 on Advances in Earth Oriented Applied Space Technologies:
https://spaceref.com/newspace-and-t...r-key-to-the-universe-by-sir-arthur-c-clarke/
While the engineering challenges are interesting, they are not the biggest obstacle. I remind you that the longest time any human has spent outside of Earth's gravity is 12 days, all the while the reassurance of Earth's appearance in view, and a comms delay of less than a second. The comms delay on Mars is about 20 minutes and Earth is invisible. Human minds would collapse long before any successful mission.
This thread is an amusing case of not seeing the wood for the trees 🥹
This thread is an amusing case of not seeing the wood for the trees 🥹
So a year in zero gravity at the ISS doesn't count?
Like no two zero gravities are the same, and only your kind counts? Care to explain that to the astronauts?
It is clear to me you are switching to troll mode and I will place you on my ignore list. All the best.
Jan
Like no two zero gravities are the same, and only your kind counts? Care to explain that to the astronauts?
It is clear to me you are switching to troll mode and I will place you on my ignore list. All the best.
Jan
The SS Nonsense on which you set sail. I twice linked an article discussing the stranded astronauts already multiples of 12 days in space, with expectation of many more months to come.
"Reminder" is a middle-school rhetorical tactic implying that your nonsense is a fact I already know. Your persuasion skills are white belt grasshopper.
Not that it's relevant to anything mentioned here, but the Moon orbits the Earth, and thus is "in Earth's gravity."
If there's any relevance to being in LEO (as in a year on the ISS, as several have done) vs. on and around the Moon, it's that the Van Allen Belt protects from radiation in LEO, but I don't know if any recent posts have anything to do with that.
If there's any relevance to being in LEO (as in a year on the ISS, as several have done) vs. on and around the Moon, it's that the Van Allen Belt protects from radiation in LEO, but I don't know if any recent posts have anything to do with that.
Gravitational fields or more specifically spacetime warped by mass is unavoidable. The degree of warpage varies, we may surf upon it in a seemingly "weightless" state of orbit, but particularly inside a galaxy where the action is gravity rules!
I reply to the only intelligently made comment. As mentioned earlier, there is a Lagrangian point, named after the Italian mathematician Joseph-Louis Lagrange, where the gravity of the moon influences the craft more than the gravity of Earth. Beyond that point your can reasonably say that the craft is in moon orbit, even though the moon is in earth's orbit. This is QED 🥹
To get out, to spread out into space, people would have to work together. State of planet and society shows that only few are capable of it. Time and effort goes into survival for some, and those who are in the west are either reaping their surroundings for their own good, or watching tv and caring and fighting things that are irrelevant to anything, result of both is more pollution on the planet. Step out, look at grand scheme from as far perspective and vast timescale as you can, and it's quite obvious 99% of people care only what is in front of their nose within very short timescales.