The End of the Space Age

[Sarevok]

The moon has 1/6 Earth gravity. Which is very different from having no gravity at all.

[Sarevok]

@Skgoa

What do you think of the Rocket a Day essay ? Here, John Walker, the founder of Fourmilab and creator of Autocad amongst other things, argues that mass production of small,simple rockets is the key to lowering costs.

Suppose he is correct. Could industrial approaches like assembly lines allow us to churn out rockets in a manner similar to automobile production ?

[PeZook]

If we are talking about single people just living for a while, most problems have been solved sufficiently. Actual populations living up there for their whole lives is something else entirely, though. E.g. no one has had a baby in space, yet. So while people should be ok for a couple of years, nobody really knows how easy or hard real colonization is going to be. Don't know if that is an argument for or against your position, so yeah.

Well, you will obviously ramp up presence in space in intervals and milestones. We're at six people on a space station for a couple months right now, so we should move on to a base on the Moon, make the stays longer, increase the crews etc while working out the problems as they appear.

Nobody went straight to the Moon in the apollo era, they first worked out the basics: first orbital flights were literally about stuff like "Can you take a dump in space? Can you sleep in space?"

[Sarevok]

Well one could argue that we did go to moon straight away while skipping the prerequisites. Now spaceflight is paying the price because the drive that once existed to justify the cost of that infrastructure is hard to come by.

[PeZook]

Huh? What prerequisites did we skip?

[Sarevok]

Von Braun's original plan for building up stations, propellant depots and spacecraft assembly in Earth orbit. And then moving from there to the Moon or beyond.

[FSTargetDrone]

You require hours of exercise daily to prevent bone and muscle wastage, and then when you come back it's still weeks of physio.

It's worse than that. Bone loss happens despite exercise:

Weakening of the bones due to the progressive loss of bone mass is a potentially serious side-effect of extended spaceflight. Studies of cosmonauts and astronauts who spent many months on space station Mir revealed that space travelers can lose (on average) 1 to 2 percent of bone mass each month.

"The magnitude of this [effect] has led NASA to consider bone loss an inherent risk of extended space flights," says Dr. Jay Shapiro, team leader for bone studies at the National Space Biomedical Research Institute.

However, fish oil may help:

Fish Oil Could Reduce Bone Loss for Astronauts in Space
by Denise Chow, SPACE.com Staff Writer
Date: 19 May 2010 Time: 10:28 AM ET

A group of nutrients found in fish oil, known as omega-3 fatty acids, may help mitigate bone breakdown that occurs during spaceflight and in those who suffer from osteoporosis, a new study suggests.?

As NASA sets its sights on long-duration missions to Mars and an asteroid, scientists are working hard to understand and cope with medical issues, such as bone loss, that accompany and are likely exacerbated by lengthier space travel.

The NASA-sponsored study built upon decades of research that has examined ways to halt bone density loss in astronauts. The study's findings could have significant implications for space travelers, but also for those who are susceptible to bone loss here on Earth.

(article continues)

[Skgoa]

@Skgoa

What do you think of the Rocket a Day essay ? Here, John Walker, the founder of Fourmilab and creator of Autocad amongst other things, argues that mass production of small,simple rockets is the key to lowering costs.

Suppose he is correct. Could industrial approaches like assembly lines allow us to churn out rockets in a manner similar to automobile production ?

I know that essay and I agree wholeheartily. I even thought about how I would implement something like that. The problem is getting someone to loan you the cash to do it, as it runs counter to all established business modells in this area. :/
Thing is, with modern CAD, CFD, the ability to order parts on the internet and just plain advances in production and materials (i.e. its getting cheaper to do more complex things) it only going to get easier. My university already has small student run projects that design and built their own airplane, race car and even a (very small) satelite that is going to launch in a couple of years and that will have scientific experiments on board.* My university also has it's own (small) rocket engine test facility. So if funding were available, we could get this thing on the road. And I just can't believe that an eastern german university is the best equiped institution to do this IN THE ENTIRE WORLD.

But unfortunately there is almost no scientific value in a rocket of this size and there are a number of existing launch platforms these payloads can hitch a ride on. So there is no self-evident drive/business case to do it.


*If anyone cares: I have worked on the sattelite. We are doing two main experiments, 1) meassuring atomic oxigen in LEO and 2) testing new lightweight and flexible solar cells. We are also launching the newest and fastest processor that has ever flown to space. (Unless someone else beats us to it, of course.) When I left the team due to time constraints, we were thinking about using it to test the effects of space on modern chips, once the other experiments had collected sufficient data.

[PeZook]

His comparisons to the automobile industry are utterly absurd, though. The tolerances involved are orders of magnitude different. A car can easily tolerate having a centre of mass shift during operation, for example.

[someone_else]

For all the hate you may have for Soviet Russia, their cosmonauts were chosen among very fit people, all astronauts are very fit people too.
The average joe drinking beer and doing barbecues with his dog is another matter alltogether.

As for gravity and excercise... Gravity Loading Countermeasure Skinsuit may be of assistence. It is a modified space activity suit that basically simulates the gravity's pull on your body with elastic material.

The main issues that remain are about circulatory system. Veins aren't all alike, some rely on gravity to drain their area. Without gravity you get that some blood remains there since the heart is a pushing pump that sucks at pulling.
Since the blood pressure sensors of the body are in the neck, and that fluids tend to accumulate in the head/neck/torso due to the above issue (veins in that area tend to rely on gravity to work, since those areas are higher or at the same level than the heart), it is detected as blood overpressure, and procedures to decrease such pressure below normal levels begin (basically you pee more).
Then the blood thickens too much since you expelled too much liquids, and since the body won't add more water due to erroneous pressure detected if it does so, it decreases the production of blood cells.

This takes a while to become a serious issue, but has the potential to be the next pain in the ass to solve after we solved the bone mass loss issue.

Theoretically any kind of gravity (even microgravity like on the Moon) should have an effect on this issue. How well will it be is still unknown, and will be until we start placing people there.

But frankly, I'd like to see more research in spinning stations simulating Earth gravity than trying to colonize the moon.
It's far closer to us cost-wise and would give the highest benefits short-term.
And I've never been a fan of planetary colonization with the crappy planets we have in the solar system anyway.

What do you think of the Rocket a Day essay ? Here, John Walker, the founder of Fourmilab and creator of Autocad amongst other things, argues that mass production of small,simple rockets is the key to lowering costs.

It is also available on astronautics.com.
I'm not skgoa but I can tell that the essay is mildly half-assed although could be correct in the end.
He says that making a rocket engine with similar reliability to a combusion engine isn't so hard. The conditions a rocket engine must withstand are kinda different, usually something that would incinerate the car in seconds and turbopumps handling cryogenic fluids (the fuel) at ludicrous speeds.
Then, he is comparing the costs of a sub-orbital vessel (the V2) to something supposed to achieve orbit, which is an entirely different beast. A lot of medium-range SAMs have the actual power to go sub-orbital for around few millions a pop, and could do that since at least the sixties.
It's staying in space that requires crazy speeds, just reaching it is a joke.
Also, the V2 has the enviable record of "more people killed in its construction than from its use", but it's tangential to the discussion here.

The scenario becomes interesting if instead of having the newly produced rockets do no goddamn thing and some government entity stockpiling them and launching concrete in space due to lack of customers you have the rockets fly to deliver propellants to a depot. That's why I have a positive attitude towards propellant depots in space. They aren't just useful per-se, but also create a market for Surface-to-LEO rockets to get cheaper.

I think it could be achievable on the relatively cheap if OTRAG is anything, a good idea that was killed by political pressure in the Cold War (they were germans and apparently none wanted them to have long-range rockets at the time, then none wanted shithole countries to have it either and pressured such conuntries to make them go away).

It would have achieve theoretically 2700 dollars per kg, still an awful lot close to what we have already today. Although as Skgoa said, we are getting better at making stuff than we were in Cold War, so it may go down dramatically.
Zenits for example cost around between 30 and 50 millions and deliver 13 tons, that's between 2300 dollars per kg and 3800 dollars per kg.

There is also the Aquariuswhose main trick was the relatively low success rate, at around 2/3 of the launches would be successful. That thing is supposed to have a launch price of around 1 million and lift 1 ton to orbit. A price of 1000 dollars per kg. But it is supposed to be a SSTO, and as such most experts tend to look at the design with distrust.

We are doing two main experiments, 1) meassuring atomic oxigen in LEO

I sense a second goal behind this.
LEO propellant manufacture maybe? Oxygen is 80% of the fuel you need by mass in a lox/lh2 rocket, having 80% of your fuel already in space would be cool. But harvesting it too lowwould require nonsense like 10 megawatt nuclear reactors. Staying in the areas where the oxygen is in its atomic form lessens the drag so you can use solar panels and has the benefit of not having to separate the oxygen from buttloads of nitrogen too.

But maybe I'm just a psycho conspirationist, pulling it off is hard and there are only a couple papers about modern designs on the net (and one I cannot have access).

[PeZook]

But frankly, I'd like to see more research in spinning stations simulating Earth gravity than trying to colonize the moon.
It's far closer to us cost-wise and would give the highest benefits short-term.
And I've never been a fan of planetary colonization with the crappy planets we have in the solar system anyway.

It's not, actually.

You can build facilities on the Moon utilizing local materials ; You have to lift everything used to build a LEO space station. Essentially, Lunar gravity is nearly free of charge ; The extra delta-V needed to go there and land is tiny compared to what you need to get into orbit: the entire Apollo stack as it was before TLI weighed 120 tonnes (spacecraft, S-IVB and fuel) and it was enough for the entire mission.

[Skgoa]

The great advantage Station offers us is that it has a continuous human presense. I.e. you have people who can assemble and fix things. Thats why VASIMR (or however that is spelled) and inflatable modules will be tested there.

Theoretically any kind of gravity (even microgravity like on the Moon) should have an effect on this issue. How well will it be is still unknown, and will be until we start placing people there.

But frankly, I'd like to see more research in spinning stations simulating Earth gravity than trying to colonize the moon.
It's far closer to us cost-wise and would give the highest benefits short-term.

Station was supposed to get a centrifuge and I have seen a NASA BEO study featuring a ring that is used to induce centrifugal artifical gravity.

And I've never been a fan of planetary colonization with the crappy planets we have in the solar system anyway.

Yeah well, tough luck.

I'm not skgoa but I can tell that the essay is mildly half-assed although could be correct in the end.[...]

While you are right in the points you make, the essence of this oppinion piece is still true. I.e. mass production would drastically reduce cost and low cost + high availability would create an entire new market. spaceX is almost there, Arienespace is going to get close if the plans for Ariane 6 can be realized, too.

We are doing two main experiments, 1) meassuring atomic oxigen in LEO

I sense a second goal behind this.
LEO propellant manufacture maybe? Oxygen is 80% of the fuel you need by mass in a lox/lh2 rocket, having 80% of your fuel already in space would be cool. But harvesting it too lowwould require nonsense like 10 megawatt nuclear reactors. Staying in the areas where the oxygen is in its atomic form lessens the drag so you can use solar panels and has the benefit of not having to separate the oxygen from buttloads of nitrogen too.

But maybe I'm just a psycho conspirationist, pulling it off is hard and there are only a couple papers about modern designs on the net (and one I cannot have access).

The actual #1 reason to do it is: "because we want to know what is up there." I.e. Science. The #2 reason is that atomic oxygen has that unnerving tendency to make space hardware rot(/rust) away amazingly fast. Knowing the distribution of concentrations of the stuff in the upper atmosphere is essential to planning long duration missions in these orbits. Harvesting it... I know of no serious plan to do that, yet. But its an interesting idea that would actually make a lot of sense, once orbital fuel depots are established. We would need entirely new aerodynamic(!) satelites, though. Maybe even nuke powered, so that no solar panels are there to create drag and I guess an ion engine would be ideal.
I actually have a couple of ideas going through my mind, now. The big question is how to pressurize it to liquid without massive use of energy, though. But maybe its jsut an area that I know to little about...

[someone_else]

You can build facilities on the Moon utilizing local materials ; You have to lift everything used to build a LEO space station.

I was thinking short-term. Reaching the moon nowadays is expensive, and the infrastructure to make what you say happen is not going to be light either (they are lighter than dropping a base from Earth, but they aren't light). Since there is no market whatsoever for them and no government seems interested, that's unfeasible.

I was thinking of a small and simple design with an habitat and a counterweight (the empty upper stage is perfect for this) on a truss pole.

That's a research station, and can become a space hotel, not a fat-ass colony. Being a spinning thing you can vary the gravity of the habitat by just climbing the truss and see what is the optimal setup for life in space. If shit hits the fan everyone goes on the Soyuz and gets down on Earth.

For serious work yes, moon elevators and moon buggies feeding the dust to EML1 solar ovens that make whatever is needed and bring fuel for the EML1 depots (in the "middlepoint" between Earth and Moon deltav-wise). But this is still somewhere in the future.

I actually have a couple of ideas going through my mind, now.

For futher reading:
A free paper.

An IEEE article where I can see only the abstract.

An articlefocused on something else (interpersonal reactions or something like that) takling a bit of the original PROFAC design at page 16.

[Sky Captain]

What about clustering smaller rocket stages together to create a heavy rocket for occasional heavy/bulky payload? How cost effective is that vs one big fixed size rocket like SaturnV Basically what DeltaIV does and Falcon9 will do. SpaceX also have design for a rocket that in single core version would lift 30 tons and in 3 core version ~120 tons. In single core mode it could stilll be used to launch big geostationary sattelites so it would get several flights per year and if the need arises it relatively easily could be turned into SaturnV class rocket while still using same production lines and workforce, only launch pad would need to be upgraded.

[SpaceMarine93]

I guess Humanity faces extinction after all.

[HMS Sophia]

I guess Humanity faces extinction after all.

...
Why?

[Simon_Jester]

I guess Humanity faces extinction after all.

I presume you would prefer to keep flying the poor birds until they all got so old they all burn up on reentry?

[HMS Sophia]

I did like cracked.com's reasoning for why we should keep flying space missions. It is mankind's polite rebuttal to the meteorite. Alternatively:

one mad, screaming, man-made asteroid hurled right back up into the face of nature, just to prove to the bitch that she doesn't have a lock on that kind of thing?

[PeZook]

I guess Humanity faces extinction after all.

For God's sake, people have been discussing spaceflight for two pages now, and that's your idea of a contribution?

Start commenitng meaningfully and on topic, or I will start flushing your posts to a more deserving place. I'd flush the above pointless one liner too, but I still hope (possibly against better judgement) you can improve.

You better prove me right.

[PeZook]

What about clustering smaller rocket stages together to create a heavy rocket for occasional heavy/bulky payload? How cost effective is that vs one big fixed size rocket like SaturnV Basically what DeltaIV does and Falcon9 will do. SpaceX also have design for a rocket that in single core version would lift 30 tons and in 3 core version ~120 tons. In single core mode it could stilll be used to launch big geostationary sattelites so it would get several flights per year and if the need arises it relatively easily could be turned into SaturnV class rocket while still using same production lines and workforce, only launch pad would need to be upgraded.

It's fundamentally a sound approach, but I am skeptical of the launch costs estimated by SpaceX. They have already shown their bombastic estimates for the Falcon 9 were quite a bit off.

Plus, of course, for manned launches it's the launch procedures and missions control which are the costly part, not really the rocket itself.

[Broomstick]

I guess Humanity faces extinction after all.

Humanity faces that regardless of whether we go into space or not. No species lasts forever. Either H. sapiens dies out with no descendants, or the alternative is to evolve into another species (or several). Whether that happens on or off Earth is a different question.

[Skgoa]

Clustering is nothing new. Indeed, its the principle that got and gets most rockets (above a payload of a couple of tons to LEO) of the ground. The F1 rocket engine just barely managed stable combustion due to it's size and they still had to cluster five of them to get a Saturn V going. But clustering is also an unforgiving heartless bitch. IIRC Falcon 9 Heavy is supposed to have 27 engines in three cores... I really hope it works out for them, but greater minds than Elon Musk and his crew have failed at this level of complexity. E.g. the N1 rocket: the Sowjet Union had a staggering number of relatively cheap rocket engines to throw away with each launch and even expected several engines to fail right from the start. It still didn't work out.
So yeah, if you can make it work without adding to much complexity, its a great idea. But so is just using a bigger engine in the first place. Rocket science/engineering is always an effort to achieve the nigh impossible by getting the most out of what you have. "monies per payload" is the metric that is important here, nothing else.

[PeZook]

Yeah, the Falcon Heavy's massive number of engines stands to be a serious problem. Modern engineering might solve it...then again, it might not.

The R-7 family got more reliable as it reduced the number of engines, though ,so the trend does not look all that positive. Modern Soyuz launchers have five engines in the first stage, and one each in the other two stages.

It used to be IIRC TWENTY separate engines in the first stage. Didn't work that great.

[Luke Skywalker]

Good to know! Now we Americans can get back to more important things, like finding more painful waterboarding methods and killing more Arabs.

[Sky Captain]

IIRC N1 failed partially because it lacked proper sensors and computer control systems to keep under control so many engines especially when some of them fail. Today sensors and computers are far better so it should be a solvable problem. Main concern would be if one of those 27 engines fail explosively and damage other nearby engines causing rocket to explode. Howewer SpaceX also have a plan to develop more powerful engine if there is suficient demand for Falcon Heavy to have only 1 engine on each stage like DeltaIV Heavy and also to have powerful engine to use on larger rockets if there is demand for even more lift capacity.

As I understand SpaceX approach is: we will develop Falcon Heavy by using hardware we already have and see if there is demand for rocket of that size and if there is then we will develop better engine and upgrade the rocket to make it more reliable which sounds like a reasonable plan.