Forget About Humans On Mars

[BobK]

At least for a long time.
Some proponents of human missions to Mars say we have the technology today to send people to the Red Planet. But do we? Rob Manning of the Jet Propulsion Laboratory discusses the intricacies of entry, descent and landing and what needs to be done to make humans on Mars a reality.
Article (http://www.universetoday.com/2007/07/17/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/)

[Puppycow]

And this article is only about the difficulties of landing a large lander on mars. There are many other problems as well.

The solution is not so hard, though:
Domo arigatou, Mr. Roboto!

There's no need to send humans.

[andyandy]

very interesting article.

I hadn't realised just landing would be so tricky....

how about if they find a reallly big crater, and aim for that, thus giving them a few hundred extra metres to play with?

Of course, then you'd be stuck at the bottom of a huge crater....

so, instead of bringing astronauts, take some of the world's best free-climbers....

problem solved.

:D

[Puppycow]

I bet that we will have intelligent robots with equal or superior capabilities for this work long before we have the technology to safely transport, land and return human astronauts.

[Beausoleil]

very interesting article.

I hadn't realised just landing would be so tricky....

how about if they find a reallly big crater, and aim for that, thus giving them a few hundred extra metres to play with?

Of course, then you'd be stuck at the bottom of a huge crater....

so, instead of bringing astronauts, take some of the world's best free-climbers....

problem solved.

:D


Martian topography is a bit unusual - the northern hemisphere is low and flat while the southern hemisphere is high and cratered (the volcanic region Tharsis is on the boundary and elevated). The lowest point is the bottom of the Hellas basin in the southern hemisphere (iirc). But I think the atmospheric pressure variation is a factor of 5 or so (2 scale heights? - I should check, I guess, I've not been thinking about Mars for a while). So I don't think that will solve the problem.

[Quakeulf]

Calling all sci/fi-writers!

[mhaze]

At least for a long time.

Article (http://www.universetoday.com/2007/07/17/the-mars-landing-approach-getting-large-payloads-to-the-surface-of-the-red-planet/)

This article is very misleading. The issues of reentry capsule weight versus cross section and how that affects reentry profile in a given atmosphere or the relative lack of it is well understood. The solutions are well known.

So, basically, the article is wrong. There is no difficulty in putting a manned lander or large reentry vehicle on Mars. The characteristics of the reentry are calculated and the vehicle is designed to accomodate that.

What may really be hard to deal with is the Martian dust, which is a strong oxidixer. Supposedly it will burn your skin. That's not good....

[PixyMisa]

This article is very misleading. The issues of reentry capsule weight versus cross section and how that affects reentry profile in a given atmosphere or the relative lack of it is well understood. The solutions are well known.
This is true, however this

So, basically, the article is wrong. There is no difficulty in putting a manned lander or large reentry vehicle on Mars. The characteristics of the reentry are calculated and the vehicle is designed to accomodate that.

doesn't follow. The problem is well-understood, and has been for some time. But that doesn't imply that a solution is readily available.

It can certainly be done; it's just a difficult engineering problem - i.e. expensive.

[PixyMisa]

Martian topography is a bit unusual - the northern hemisphere is low and flat while the southern hemisphere is high and cratered (the volcanic region Tharsis is on the boundary and elevated). The lowest point is the bottom of the Hellas basin in the southern hemisphere (iirc). But I think the atmospheric pressure variation is a factor of 5 or so (2 scale heights? - I should check, I guess, I've not been thinking about Mars for a while). So I don't think that will solve the problem.
Or do the reverse: Land atop Olympus Mons, where (according to Wikipedia) atmospheric pressure is only 5% to 8% Mars normal, i.e. near enough a vacuum for spaceflight.

Getting down from there to explore further is left as an exercise for the reader.

One mitigating factor the article doesn't mention is that while the fuel for a retro-rocket descent would be substantially greater than for the moon landings, you wouldn't have to take along fuel for the ascent; you could manufacture that on the ground (given an appropriate landing site, at least). And while the main crew vehicle has to land in one piece, supplies and equipment can be dropped from the orbiter using some combination of parachutes and airbags.

Actually, if you wanted to get adventurous, you could probably do that with the entire mission, astronauts included. You'd want to spend a bit of time on target practice first, though...

[Hellbound]

Bah.

All you have to do is build a capsule with 3' thick titanium-alloy walls, gel-filled for shock absorption and to counter G-forces, and then fire it like a giant BB into the soil.

Make sure they have shovels.

:D

[mhaze]

This is true, however this
doesn't follow. The problem is well-understood, and has been for some time. But that doesn't imply that a solution is readily available.

It can certainly be done; it's just a difficult engineering problem - i.e. expensive.

Sounds a bit like rocket science?:)

[Hellbound]

mhaze:

See my previous post. It doesn't have to be rocket science :D

[ponderingturtle]

This is true, however this



doesn't follow. The problem is well-understood, and has been for some time. But that doesn't imply that a solution is readily available.

It can certainly be done; it's just a difficult engineering problem - i.e. expensive.

Given the nature of the other challanges involved this does not seem like it would be the hardest

[mhaze]

Yes I like that.

We could do that thousands of times with astronauts in suspended animation, and also fire into the mars surface and bury, hundreds of large terraforming machinery. Each would have multimodal colonizing, soil feertilization and debris/vermin removal capabilities.

Later, when enough of these assets were in place, THE PLAN would commence.

[Overman]

What about Tethering something to mars....Perhaps shoot down something that violently buries itself and attaches to the Mars, then just slide things down the cable?

[Hellbound]

Yes I like that.

We could do that thousands of times with astronauts in suspended animation, and also fire into the mars surface and bury, hundreds of large terraforming machinery. Each would have multimodal colonizing, soil feertilization and debris/vermin removal capabilities.

Later, when enough of these assets were in place, THE PLAN would commence.

Yes, precisely *rubs hands together*

BWAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHahahahahahah ahahahahahahahahah *gasp* *choke* *wheeze* *deep breath* HAHAHAHAHAHAHAHAHA!!

[PixyMisa]

Given the nature of the other challanges involved this does not seem like it would be the hardest
True enough.

A number of difficulties with the Mars mission have been raised; all of them can be solved by the judicious application of money. We could build a 10,000 ton spaceship with a crew of 50 if we wanted to; it's just that it would cost a trillion dollars. Though if NASA were funded proportionately today as it was during Apollo, that would be less than ten years' budget...

[mhaze]

http://en.wikipedia.org/wiki/Sea_Dragon_(rocket)

550 metric tons into LEO

There were other designs for truly huge rockets.

Not a trillion dollars unless the governments get involved....

[andyandy]

And while the main crew vehicle has to land in one piece, supplies and equipment can be dropped from the orbiter using some combination of parachutes and airbags.

Actually, if you wanted to get adventurous, you could probably do that with the entire mission, astronauts included. You'd want to spend a bit of time on target practice first, though...

quite, what's to stop you using an orbiter from which human sized capsules are launched onto the ground? Surely then they could use the airbag system used with [erratic] sucess on other missions....take 5 astronauts, you're likely to get at least 1 down there in one piece....:)

[mhaze]

Clearly, from the physics of the problem, smaller, lighter and cheaper is better and safer. Clearly, the way is just to build a small re entry machine with principal components being

1. a seat for the astronaut
2. retro rocket and fuel
3. cone shaped deacceleration chute (detaches when not needed)
4. final parafoil chute for final approach (detaches when not needed)
5. 2 wheels on welded chrome moly tube framework supporting seat for astronaut/and possibly rider plus ground propulsion unit. Wheels are required since in the thin air, approach and landing speed would be in the neighborhood of 100 km/hr.

Bikers for Mars?


I'm sure we'd get takers for this jump.

[RecoveringYuppy]

http://en.wikipedia.org/wiki/Sea_Dragon_(rocket)

550 metric tons into LEO

There were other designs for truly huge rockets.

Not a trillion dollars unless the governments get involved....
Yes, I frequently think it's time for NASA to get out of the way. I think their willingness to spend big bugs is keeping costs unnecessarily high.

And if politics would get out of the way a private company looking for the lowest price available would find a lot of lower cost options even now. The Russians actually built and flew a 100 ton payload rocket they were once willing to launch for about 500 dollars/pound cost. They had larger versions of it on the drawing board and they can probably still build it.

Your link seems to be broken:

http://en.wikipedia.org/wiki/Sea_Dragon_%28rocket%29

[Jimbo07]

And if politics would get out of the way a private company looking for the lowest price available would find a lot of lower cost options even now.


Really? Which private companies, exactly, are ready to step up to this... even now?


The Russians actually built and flew a 100 ton payload rocket they were once willing to launch for about 500 dollars/pound cost. They had larger versions of it on the drawing board and they can probably still build it.

Wow! Those Russians rock! This habit of theirs of throwing welded steel cans into orbit is just a diversionary tactic. Russian technology is so cool...

:rolleyes:

[Michael Redman]

Let's start by sending a robotic ship to install a space elevator.

After we build our, of course.

[RecoveringYuppy]

@Jimbo: Step up to what?

[patnray]

Many of you know that I am not a proponent of manned space exploration. Putting men on Mars is a huge challenge, and I don't know of a single question about Mars that could not be answered much more cheaply and quickly using robotic exploration.

But it is fun to speculate about how a manned presence on Mars could be achieved. Given the constraints discussed in this article it is clear that a manned lander must be as small and light as possible. One way to do this is to strip all other functionality from the lander. Send all the supplies, living quarters, power generators, even the return launch vehicles, ahead of the people in a series of modules small enough to land safely (but much more roughly than required for humans). The human lander would be a throw away used solely for landing and thus could be much smaller than envisioned in the article.

Supporting this approach would require several large spacecraft that shuttle back and fourth between Earth orbit and Mars orbit. They would take equipment, supplies, and people to Mars and return people and Martian rocks back to Earth. There would always be at least one on the way to Mars and at least one making the return trip. We probably already have sufficient technology to create such ships, including the shielding needed to protect the occupants from cosmic rays and solar flares.

The return launch vehicles would only have to be large enough to reach Mars orbit and rendezvous with the “mother ships” (like the return portion of the LEMs that landed on the moon). They could be pre-landed on Mars without fuel and even in several pieces if necessary. Fuel (and water and oxygen) could be manufactured on Mars from tanks of hydrogen and the carbon dioxide in the atmosphere using solar and/or nuclear power.

It would be a grand (and enormously expensive) adventure. Very romantic and awe-inspiring. But it would accomplish little. 99% of the effort would be related to survival. Although it would advance our engineering capabilities, it is questionable whether it would contribute anything to science that could not be learned by other methods.

All of this would require advanced robotic technologies – the same technologies needed to explore Mars remotely. So it would seem prudent over the next decade or so to concentrate on developing those technologies and continue our unmanned exploration rather than rushing into a manned program. IMO.

[Jimbo07]

@Jimbo: Step up to what?

I don't know. You're the one who suggested that the government should make way for private companies. What do you mean, exactly? What are private companies able to accomplish in space right now that NASA is not?

[tracer]

What may really be hard to deal with is the Martian dust, which is a strong oxidixer. Supposedly it will burn your skin. That's not good....
The dust on the moon was basically microscopic shards of glass, but that didn't stop the Apollo astronauts from walking around outside on the stuff. They just had to remove it from their suits before they could walk around in the LEM.

Surely, the Marstronauts could do the same thing.

[RecoveringYuppy]

I don't know. You're the one who suggested that the government should make way for private companies. What do you mean, exactly? What are private companies able to accomplish in space right now that NASA is not?
Lower cost access to space is what private companies can accomplish. NASA is presently throwing money at the very expensive shuttle. And they are planning another expensive launch system (Orion/CEV). IMO that's inflating booster prices and NASA should abandon those as quickly as possible in favor of using existing technologies. NASA should design missions around existing boosters. Contract launches out to the lowest bidder including foreign ones when possible.

[PixyMisa]

Right. Launching everything with a human-rated vehicle is not a good way to keep costs down.

[Michael Redman]

Many of you know that I am not a proponent of manned space exploration. Putting men on Mars is a huge challenge, and I don't know of a single question about Mars that could not be answered much more cheaply and quickly using robotic exploration.How about the only question that really matters: What is it like to be there?

[PixyMisa]

The skiing is great. The fishing, not so much.

[Jimbo07]

Lower cost access to space is what private companies can accomplish.

How?

NASA is presently throwing money at the very expensive shuttle.

True... but this is a problem that is thirty years old. It's time to move on.


And they are planning another expensive launch system (Orion/CEV). IMO that's inflating booster prices and NASA should abandon those as quickly as possible in favor of using existing technologies.

Which booster is ready to put 70 tons into lunar orbit? Delta IV Heavy? Arianne 5? Mythological Russian Booster X?


NASA should design missions around existing boosters.

I disagree. NASA should be pushing technological and exploration boundaries. Everyone else should be looking at low-cost, off-the-shelf technologies... sorta like what's happening now!


Contract launches out to the lowest bidder including foreign ones when possible.

Non-NASA regulations are as much a problem with this as anything. The U.S. has put export restrictions in place to prevent weapons transfers, which wind up impacting civilian space launch and other technological activities. My design team at school wound up running afoul of this. The folks interested in homeland security are not necessarily the same as those interested in spaceflight.

...

I actually favour the current paradigm. The biggest engineering projects like the ISS can only be accomplished with the BIG gov't funding. There is not sufficient venture capital for those sorts of things. In fact, the ISS is so big that it's relying on multinational collaboration. Several governments have money tied up in it. This is the model that NASA is currently espousing for a Mars trip.

The private players are all chipping away at individual pieces of the problem. It seems like Scaled Composites is leading the pack, but it has only achieved sub-orbital spaceflight so far. Bigelow has successfully launched two space modules, but they are only test beds. Space elevators (which is what my team was (and is) involved with), are still stuck on the... uh... ground floor, so to speak.

I'm hoping that in a few years we'll see a successful space hybrid of government and private ventures.

Anyone who thinks NASA should get out of the game altogether had better have a detailed idea of what to do afterward. I held this same opinion at one time, and found it to be over-optimistically biased toward the private sector.

[RecoveringYuppy]

How? [can they accomplish lower cost access to space]
By charging less? You do know the shuttle is the most expensive launch system every developed, right? Not sure why you've questioned this twice.

Which booster is ready to put 70 tons into lunar orbit? Delta IV Heavy? Arianne 5? Mythological Russian Booster X?

Huh? What mission is ready to put 70 tons in to lunar orbit? And even if there is a need for this, what makes NASA the likely candidate to be able to design and build the booster well?

I disagree. NASA should be pushing technological and exploration boundaries.
OK. But why boosters and expensive manned missions to deep space? Looks to me like NASA's poor choices in delivery systems have hobbled it's ability to explore and expand technology. Last I checked 15 billion is slated on NASA's next delivery system before it will be capable of doing anything at all. Fifteen billion can buy a lot of launchers right now. Considering that the planet has already developed boosters fully ten times cheaper than the shuttle what are the odds that this next "shuttle derived" booster that NASA is planning will achieve any cost benefits at all?

I think the odds are strong that we'll spend that 15 billion and then, if we're lucky, find out thats it an improvement on the shuttle but is still more expensive to fly than currently existing technology. If we're not lucky it will be as or more expensive than the shuttle.

This aspect seems nearly a no brainer to me. NASA is planning on throwing 15 billion or so at a new booster they call "shuttle derived". Where is the sense in using the most expensive booster on the planet as the basis for the next generation when other boosters have already left it in the dust? Why not spend that 15 billion to actually carry out missions using existing boosters? We should scrap the shuttle now before it kills 14 more people.
Non-NASA regulations are as much a problem with this as anything. The U.S. has put export restrictions in place to prevent weapons transfers, which wind up impacting civilian space launch and other technological activities. My design team at school wound up running afoul of this. The folks interested in homeland security are not necessarily the same as those interested in spaceflight.
Very true. I think that arbitrary restrictions on purchasing foreign launchers should be eliminated (not all are arbitrary of course). But surely something like the ISS where Russians are participating shouldn't fall in to the restricted technology. Would should've used almost entirely Russian materials for it. And we really should have paid them to launch the whole thing.
I actually favour the current paradigm. The biggest engineering projects like the ISS can only be accomplished with the BIG gov't funding. There is not sufficient venture capital for those sorts of things.
The first question is what do we need ISS for? It's primary missions seems to be sapping the budget.

And it only needs to be big bucks if you insist on wasting money. ISS or something similar should have been done with leftover Soviet technology. Politics drove the cost up by refusing to use cheap Russian materials. They had space station modules they hadn't used. And we really should have had them launch the whole thing. Which NASA contractor was it that recommended that originally? TRW, BA&H? Can't remember but I'd say they've been vindicated.

In fact, the ISS is so big that it's relying on multinational collaboration. Several governments have money tied up in it. This is the model that NASA is currently espousing for a Mars trip.
The model doesn't look so good to me. ISS may not even be finished before it's mission ends.

But even within the multi-government model what was the point of using expensive shuttle launches to do it?

[Jimbo07]

By charging less? You do know the shuttle is the most expensive launch system every developed, right? Not sure why you've questioned this twice.

I haven't once questioned that the space shuttle is an expensive system. What I HAVE questioned is your so-far unsupported claim that private development is universally superior to NASA.


Huh? What mission is ready to put 70 tons in to lunar orbit? And even if there is a need for this, what makes NASA the likely candidate to be able to design and build the booster well?

None, yet. This is the mission designated for Ares V.

http://www.nasa.gov/mission_pages/constellation/ares/aresV.html


OK. But why boosters and expensive manned missions to deep space?

I think this is a separate debate from private vs. NASA. What missions should humanity pursue? THEN, which bodies should be tasked with those missions?


Considering that the planet has already developed boosters fully ten times cheaper than the shuttle what are the odds that this next "shuttle derived" booster that NASA is planning will achieve any cost benefits at all?

It's important to consider what you mean by cheaper. Yes there are systems which could launch a kg of payload for much cheaper, but there isn't a single machine in the world that has the Shuttle's capabilities. Whether or not we need those capabilities is, again, a separate debate.


This aspect seems nearly a no brainer to me. NASA is planning on throwing 15 billion or so at a new booster they call "shuttle derived". Where is the sense in using the most expensive booster on the planet as the basis for the next generation when other boosters have already left it in the dust?

Why, exactly, is the space shuttle so expensive? How has any other booster left Ares V in the dust? Name the booster.

Delta IV Heavy? No.
Ariane V? No.
Soyuz? No.
Proton? No.
Any Atlas, Pegasus, White Knight/SSO? No.
Dare I say, Saturn? Even if refurbished, still only competitive to LEO.

Technology is being borrowed from Delta IV, SST and Saturn to make this thing up.


Very true. I think that arbitrary restrictions on purchasing foreign launchers should be eliminated (not all are arbitrary of course). But surely something like the ISS where Russians are participating shouldn't fall in to the restricted technology.

Well, Russia specifically, is an issue...

Export Controls (http://www.state.gov/p/eur/rls/rm/2003/21487.htm)


Would should've used almost entirely Russian materials for it. And we really should have paid them to launch the whole thing.

You mean like the Russian-built Zarya, or Russian-built and funded Zvezda Service Module (nee MIR-2)?


The first question is what do we need ISS for? It's primary missions seems to be sapping the budget.

Again, the nature of any particular mission is a different (if related) debate than private vs. public.


And it only needs to be big bucks if you insist on wasting money. ISS or something similar should have been done with leftover Soviet technology.

Such as...


Politics drove the cost up by refusing to use cheap Russian materials.

Evidence?

They had space station modules they hadn't used. And we really should have had them launch the whole thing.

see above


Which NASA contractor was it that recommended that originally? TRW, BA&H? Can't remember but I'd say they've been vindicated.

?


The model doesn't look so good to me. ISS may not even be finished before it's mission ends.

Really? If history holds, they'll just keep redefining the mission...


But even within the multi-government model what was the point of using expensive shuttle launches to do it?

Well, the Russian components were launched with Proton/Soyuz. One of the problems with ISS is that it was designed from the beginning as a closed-loop with the shuttle. We can debate the merits of the overall shuttle program in a different go, but that doesn't really address NASA planning to move on, once the shuttle program is concluded...

... nor does it address private vs. public, aside from some hand-waving about, "private could have done it cheaper!"

[RecoveringYuppy]

IWhat I HAVE questioned is your so-far unsupported claim that private development is universally superior to NASA.

What exactly do you think I'm claiming? Somehow I don't think you and I talking about the same thing. My claim is that the world has enough boosters and that incremental improvements in those boosters is better than a long term gamble on one new NASA specified/financed booster.

IIt's important to consider what you mean by cheaper. Yes there are systems which could launch a kg of payload for much cheaper, but there isn't a single machine in the world that has the Shuttle's capabilities.

I simply mean cheaper.

IHow has any other booster left Ares V in the dust? Name the booster.

??? Ares V hasn't been built yet. I think I explained my opinion on why I don't think it's a good idea to go ahead with Ares. Two much cheaper boosters were mentioned in the conversation where you came in: Sea Dragon and Energiia. One planned and never built, another flown.

IAgain, the nature of any particular mission is a different (if related) debate than private vs. public.

??? The mission you and I are talking about in the sentences you are quoting is the ISS. That's a public mission if I understand what you mean by public.

[Jimbo07]

What exactly do you think I'm claiming?

From your first post in this thread:


Yes, I frequently think it's time for NASA to get out of the way. I think their willingness to spend big bugs is keeping costs unnecessarily high.

And if politics would get out of the way a private company looking for the lowest price available would find a lot of lower cost options even now.

and I was wondering what you meant, exactly.


The Russians actually built and flew a 100 ton payload rocket they were once willing to launch for about 500 dollars/pound cost. They had larger versions of it on the drawing board and they can probably still build it.

Do you have a linky for this?


Somehow I don't think you and I talking about the same thing. My claim is that the world has enough boosters and that incremental improvements in those boosters is better than a long term gamble on one new NASA specified/financed booster.

This is a much different claim than your first post. What makes you think a private company wouldn't have to develop a new booster?


I simply mean cheaper.



??? Ares V hasn't been built yet. I think I explained my opinion on why I don't think it's a good idea to go ahead with Ares. Two much cheaper boosters were mentioned in the conversation where you came in: Sea Dragon and Energiia. One planned and never built, another flown.

Energia (http://en.wikipedia.org/wiki/Energia)

The last paragraph seems to be largely speculation. However, this is a neat line:


The Energia and Saturn V vehicles are easily the most powerful and reliable large boosters that ever successfully flew. In all categories: takeoff thrust, launch mass, payload mass, etc. the Saturn V and the Energia are at the top of the list in some order, and every other launch system (with the possible exception of the STS) being a distant third.

The STS routinely lifts 100 tons into orbit. Problem is that a lot of that is the orbiter, with only about 20 tons of deliverable payload. The space shuttle is an experimental vehicle. The tragedy is that it remains experimental, with each launch...

We're not at a reusable stage in the space game. Back to the future, I guess...


??? The mission you and I are talking about in the sentences you are quoting is the ISS. That's a public mission if I understand what you mean by public.

The ISS mission is peripheral, I think, to what I understood us to be talking about from your first post (private vs. public).

...

Sorry, I'll refrain from pedantically going point-by-point in future posts. It's obvious that you and I both share some interest in the future of spaceflight, and that has to be a good thing! :D

I'm just curious (again, because I used to say it), what people mean, exactly, when they say that the private sector can take over.

[RecoveringYuppy]

We're obviously missing each other. It might be as simple as maybe you missing my post 28, but it looks like you saw that.
Do you have a linky for this?
I'm refering the to the Energia, which you've found a link to. Here are some links about the cost, don't know if either link is still reliable, they are old.

http://adsabs.harvard.edu/abs/1992wadc.iafcV....L

http://neptune.spaceports.com/~helmut/exploration99/strategy1/2_3_2_loe_infrastructure.html

If that 1997 price is still even close to accurate it sounds like a good deal to me. One tenth the launch cost of the shuttle per pound. One tenth the projected development cost for Ares/CEV. The firesale price back when the SU fell apart was even lower and the project didn't need to be taken out of mothballs. Ought to be on the table.

This is a much different claim than your first post.
Don't see why. My original post was to agree with and add to someone elses point that there are or have been cheap and large boosters. And what you're quoting me saying here sounds to me like a very close paraphrase of what I said in post 28.
What makes you think a private company wouldn't have to develop a new booster?

This kind of question makes me think we're miscommunicating. I'm not entirely against "developing new boosters" it's more a question of how we do it and what the starting point is. In general, it doesn't look to me like NASA is where the good ideas for future boosters are. And it looks to me like NASA is letting politics rule out some good existing designs.

I'm just curious (again, because I used to say it), what people mean, exactly, when they say that the private sector can take over.
I don't see where I said that. I said private companies would find lower cost options. You quote me at the top of your post. I only used the word "private" twice as far as I can see. Neither instance seems to say this. I'm not sure what you read in to my use of the word "private" but that would seem to be sticking point.

[Jimbo07]

I'm not sure what you read in to my use of the word "private" but that would seem to be sticking point.

You're right. I guess I should have first asked, "it's time for NASA to get out of the way," in favour of whom?

I'm sorry I picked this nit in the first place... :o

[autumn1971]

Well, eventually, if our species (we're all Homo sapiens, right? Wouldn't want to be speciesist [not a word that rolls off the tongue]) survives long enough, the problem of transporting people to extra-terrestrial, if not extra-solar worlds, is far from a trivial exercise.