New Mars Forums

I'm no expert in the field, but I personally see no chance of SPS system being built. I just don't see the energy market ever getting bad enough that it would make economic sense at current launch costs. It's not like we have tapped all the possibilities for earth-based solar power, nor other "clean" and nuclear sources of power.

Should launch costs fall drastically, the situation will of course change. Another case of "build it and they will come" situation, I suppose, similar to what has been argued here for "space tourism".

But I believe commercial manned space travel will be a much stronger driver for lower launch costs than SPS, that's for sure. I guess you could call it "build it and they will come quicker". 

My thinking in favor of sub-orbital passenger flights is as following:

1. As noted earlier billionaires rarely make stupid investment. But we've already had Paul Allen sink $20+ million into Scaled, and he has now set up a company with Rutan called "Mohave Aerospace" which owns the copyrights and intellectual property that went into the SS1/WK designs. This indicates that he is nowhere close to being done puring cash into that "hobby" of his. (And it would make no sense for him to stop after winning the X-prize, since that would have put him $10+ million in the red) In addition, Richard Branson (of Virgin fame) is rumored to be lining up to invest some of his $$$ into this same company, and he has definately been talking up space tourism.
- Also note that Allen invested all this before SS1 flew, which IMO will or already has opened up the gates to more investments. People from XCOR and TGV (X-prize competitor) have talked about how much new interest there is in investments in the suborbital/low-end space market. We space nuts all knew that reaching 100km was clearly possible - but the fact that Rutan did it and made it look so easy (relatively) has opened up the eyes of a lot of non-space-buff people all around the world.

2. Ok, so lets say you are flying sub-orbital missions. Is there any other decent profit potential in 100+ km hops outside of space tourism? Because I really don't see it...
- Ultra-fast parcel delivery? Not a chance - and you need a lot more infrastructure in lots of cities to handle that, and a whole lot more performance than 100km and Mach 3.
- Microgravity research? Give me a break - If Shuttle/Mir/ISS microgravity research hasn't yielded large breakthroughs, 3-5 minutes of flaky microgravity isn't going to either.
- High atmosphere research? Already cheaper with sounding rockets and parachute recovery.
- What remains? Space tourism.

(If one is able to scale up to higher to orbital or near-orbital, more sources of revenue become available. But if one plans to just dabble with small sub-orbital hops, there aren't a whole lot of profit-generating activities to do with it)

Now will space tourism be massively popular and kick-start a real space industry, or just be a minor blip on the radar for a few rich and adventurous? That remains to be seen. But I believe we will see some form of sub-orbital space tourism soon.

We don't have [real] space tourism yet - so I'd say it's a bit early to declare wether or not it will be a "killer app".

It looks like the SS1 flight experienced a fair bit of problems - they might have had some luck...

From this BBC article: http://news.bbc.co.uk/2/hi/science/natu … tm]X-Prize runs 'may have to wait'

... "The anomaly we had today is the most serious flight safety systems problem that we have had in the entire programme," said Rutan, during a press conference following the flight. ...

... Rutan said the team was assessing a sudden roll seconds after SpaceShipOne's motor ignited and a more serious glitch that occurred when Melvill reached the highest peak of his suborbital flight. He was attempting to tweak his altitude by manoeuvring the nose of the plane when the flight control system that operates flaps on the ship's wings failed. Melvill activated the back-up system but the ship was already off course by 35km (22 miles). The problem also ate into the engine performance during the climb to space and kept Melvill short of reaching his intended mark 110km (68 miles) above the atmosphere...

... "There is no way we would fly again without knowing the cause and without assuring we have totally fixed it because it's a very critical system," Rutan said.

I hope they get the issues sorted out so they can keep flying and try for the 110 km record again. (The X-15 has the current record for a sub-orbital aircraft at 107.5 km)

Their latest success:
http://media.armadilloaerospace.com/200 … tedHop.mpg
(source: http://www.armadilloaerospace.com/n.x/A … ws_id=263)

Earlier attempts with a test-bed two weeks ago:
http://media.armadilloaerospace.com/200 … yHover.mpg
http://media.armadilloaerospace.com/200 … tedHop.mpg

Is that cool or what?

Oh, and regarding the coloring of the martian sky. There is a simple reason - aestetics.

There are examples of when they don't do it - here is one recent: http://marsrovers.jpl.nasa.gov/gallery/ … ...br2.jpg

Can you see what happens now with the sky? Due to the panoramic camera not taking all the component images of the camera at the same time, the sky conditions/brightness change as the sun moves across the sky. So in the above image we have a sky that clearly looks "patched", since they have two choices when combining panoramas:
A) Match the ground brightness as much as possible or
B) Match the sky brightness.
The choice is of course a no-brainer. So how to fix the sky? Well, since most images don't show much of the sky, it is easier to just mask it out and fill it in with an average sky color.

There really is no sinister motive - honestly.

Yes, entering on this side and slowly spiraling down is probably the best way to enter and exit the crater.

Yep, that is the killer argument against an SDV. Sure, if we had enough space budget to continually launch Moon and Mars missions, we'd have an acceptable launch rate. But we are not likely to have such massive budgets anytime soon.

And still, a full sequence of realistic Mars missions would only use up 2-3 SDV launches per mission. And since they would be grouped around opportune Mars launch windows, we would see some years without any SDV Mars launch.

I'd say the odds are increasing every day that the Shuttle will never fly again...

But the CEV is only intended for short trips by itself. Noone is planning to go to Mars just in a CEV - that's where the CEV is attached to the larger habitat. (preferrably TransHab-type). In a Mars mission, the CEV would only be an Earth return vehicle - nothing more. (See Boeing's speculative [http://boeingmedia.com/images/one.cfm?image_id=8864]Mars spacecraft - note CEV w/ Service module on top, and a separate TransHab habitat)

If (presumably) the TransHab has a radiation shelter, that's where the crew would hide out, not the tiny CEV that is attached. Secondary radiation will always be a factor, no matter what kind of Mars mission is proposed, since it will be a practical impossibility to radiation shield the whole spacesraft.

The CEV is only a piece of the Mars plan puzzle. Just think of it as a short-range shuttle / emergency escape vehicle. Nothing more, nothing less. That is all it should be. Just a piece of a modular puzzle.

I disagree that it is worth it - not for a small 10% benefit. The following drawbacks are major:
- Significant investment and infrastructure needed for the track
- Locked into one orbital inclination

Human space exploration will become high priority if we get a serious asteroid impact scare (or actual impact).

Otherwise we'll have to wait for cheap space access - Then it won't have to be a priority but will happen anyway.