When do you think humans will land on Mars?

[WestAir]

You guys are way too optimistic. 90 years is a pretty solid ETA and even that might be optimistic. If we were discussing Luna, 2030 might be a fair prediction.

[EdFred]

There needs to be a financial/energy resource reason to go, and that's not going to happen anytime, ever, since Mars has nothing in terms of energy resource, and the market for Mars gemstones I don't see ever being lucrative. Don't count on anyone leaving Earth's orbit any sooner than 2063.

[NERVAfan]

no but it is neccisary to bootstrap production to the point where you can produce things like solar cells, wind turbines, hydro plants, and nuclear reactors/fuels. if we ruin things to the point where we need to have another industrial revolution, we might not have the fuels neccisary to move to a more technological society. and it doesnt even need to be oil. it can be any finite resource from coal to nuclear fuels. if we use all the oil and have to use something nastier like coal the next time around, that gives us less time between inustry and climate collapse to move to renewables than we had on the first go round.

i should also point out i was trying to come up with a worst case scenario. i dont think this will actually happen.

Steam engines can burn wood; you could go from wood-burning steam engines to ethanol as liquid fuel to solar/wind/nuclear.

Without fossil fuels, you wouldn't be able to industrialize on a large scale until later in the development, but it wouldn't be impossible to get there. (And once you did, you wouldn't have to replace a pre-built fossil fuel infrastructure, which is a big part of what's slowing us down going to renewables - the fossil fuel infrastructure is already paid for.)

[NERVAfan]

As for the original question, I'd say mid-to-late 2020s (12-15 years from now) if SpaceX does it (or is the leading partner/technology developer & sells services to someone else); 2030s or 2040s if China does it and if their demographic problems don't ruin their economy and thus technology before then, which is very possible; late 2030s to never if NASA does it.

[UmbralRaptor]

After 2100, but since there's no choice beyond 2040...

So how come people are doubting the expected "mid-2030s" date set by NASA?

Various programs that ultimately failed to get anywhere. eg:

https://en.wikipedia.org/wiki/McDonnell_Douglas_DC-X

https://en.wikipedia.org/wiki/Lockheed_Martin_X-33

https://en.wikipedia.org/wiki/Constellation_program

I'm going to guess that ARM will get cancelled in 2017 or 2018. That's not the only thing the SLS can do, so it might survive longer.

[Jim-Tanker]

This is my first post. Yay!

Just had to chime in with my .02c.

I would say an optimistic 2030, probably later. IMHO we need to get to the moon first and then establish infrastructure there for research and manufacturing. If we can survive on the moon then we can survive just about anywhere. Then on to Demos/Phobos and then Mars. I believe in the baby steps approach.

[Northstar1989]

I feel the need to point this out:

Once Orion/SLS is developed, it's a sunk cost.

Meaning, you can't get back the development money you already put into it. And those (and the cost of upgrading launch facilities to handle a rocket of that size) are the vast majority of the costs related to Orion/SLS.

The actual costs of building and launching an Orion/SLS rocket are MUCH, MUCH less than the costs of getting to the point where we can build and launch one. So even if political support starts to dry up, there's little reason to think we would turn around and abandon Orion/SLS...

Saturn V was abandoned, but it was a different story- the technologies behind it were becoming increasingly outdated, and Saturn V was replaced with smaller, *more modern* launch vehicles. SLS is a different story- it's very much an apex technology- meaning there's not much room to refine it further unless we move to entirely new technologies like Full Flow Staged Combustion (the only current designs for which are the Space-X Raptor engine), reusable rockets (once again, Space-X), or actual viable spaceplanes (like the "Skylon" spaceplane for which SABRE engines were developed...)

So, basically, we'll end up with either Orion/SLS or something even better. It sets a floor to be surpassed. We won't just drop the rocket we sunk all the expensive money into developing if there's no economic incentive to do so...

Orion/SLS *can* be used to re-supply the ISS. It's not a cost-effective option when you include development costs- but once again, once that money is spent, those costs become sunk-costs. It's actually an easier and more efficient option (fewer launches, docking maneuvers, and rockets to build) if you completely ignore the development and facilities costs that can't be recovered...

Remember, larger rockets are capable of higher payload-fractions. Thanks to the Square-Cube Law they have better ballistic coefficients- and experience proportionally less atmospheric drag. They can also have relatively less mass invested in flight computers (a flight computer that can guide an Ariannne 5 works equally well for something the size of SLS), fairings (once again, the Square-Cube Law in action- assuming the larger rocket carries a single, proportionally bulkier payload than a smaller rocket- such as a jumbo-sized resupply cargo for the ISS), and insulation for cryogenic fuels (due to the Square-Cube Law, and the fact that fuel tanks are pressure-vessels and thus have thicker walls with larger tanks, larger rockets have much less Thermal Leakage into the rocket proportional to their fuel volume...)

Regards,

Northstar

P.S. A note on fuel tanks and Thermal Leakage/ the Square-Cube Law. Fuel tanks are pressure vessels, meaning their mass scales linearly with volume, and their walls become thicker in accordance with the Square-Cube Law. Thus, a tank with 4 times the volume might have twice the surface area and twice as thick tank walls (exact scaling of surface area vs. wall thickness depends on shape- but mass will always increase linearly). Thermal Leakage (what drives boil-off of cryogenic fuels such as Liquid Hydrogen) is directly proportional to surface area, and inversely related to tank insulation and the thickness of fuel tank walls. Thus, larger fuel tanks experience much less boil-off even without insulation, and can either have fewer layers of insulation for the same proportional boil-off (i.e. twice the boil-off for twice the fuel volume), or the same number of layers of insulation for greatly-reduced boil-off proportional to their volume. Both options lead to superior rocket performance (especially the option to use less insulation- which saves mass).

Edited December 9, 2014 by Northstar1989

[Northstar1989]

And... I realized I forgot to answer the actual question.

When do I think humans will land on Mars? In 2040+, after either Congress has forgotten about how much SLS cost to design in the first place (if we're smart, we'll maintain manufacturing capabilities for SLS until at least 2050, if we're wise enough to design the final version to have loose enough engineering margins to have a lower per-ton payload-to-orbit cost than existing launch vehicles...) and is willing to shell out the big bucks for a flag-and-footprints exercise, or after NASA has finally finished (slowly) embracing the philosophy of In Situ Resource Utilization and is now designing all future Mars missions to make use of it (either should take at least 25 years).

Sooner if we actually have the common sense to invest in a lower-cost method of launching things to orbit than SLS: like Big Dumb Boosters (I highly doubt SLS will ever go *that* far towards cost on the inefficiency/cost spectrum determined by engineering margins- especially since the project already has a lot of momentum towards becoming an expensive "Smart Booster"...), Microwave Beamed Power Thermal Rocketry (which also places spaceplanes squarely within the the realm of feasibility, like Escape Dynamics is working on- leading to even greater cost-savings), or magnetic launch-assist systems (which, carried to an extreme, could give rockets enough velocity to escape the atmosphere with a large horizontal component, as with Star Tram; but would actually yield the greatest Return-on-Investment by simply giving a rocket a few hundred m/s of velocity right off the ground, as the first few hundred m/s are the most expensive due to the Rocket Equation...)

NASA could also reduce the fuel mass needed for a Mars injection in the first place by making use of Microwave Beamed Power for the propulsion when leaving LEO (allowing ISP of over 800s when using Liquid Hydrogen in a Microwave Thermal Rocket Engine- or even better ISP if using the microwaves to power a VASIMR or high-powered magnetohydrodynamic engine via a rectenna, i.e. Microwave-Electric Propulsion), possibly solar sails for minute course-corrections en-route to Mars, and aerobraking to reduce the fuel needed for capture. That's not to mention the potential benefits of manufacturing Methane for the return-voyage via ISRU...

If NASA got *REALLY* ambitious, they could collect the propellant needed for the outbound-journey (possibly the return-voyage as well: launching empty fuel tanks to be filled in LEO and sent to Mars-orbit ahead of the crew might be cheaper than launching the equipment necessary for ISRU) with Propulsive Fluid Accumulator satellites skimming the edge of Earth's atmosphere.

Since Microwave Beamed Power is one solution to powering these satellites' proposed nitrogen-electric thrusters (solar panels produce too much drag for their power output- the other option besides beamed power is an onboard nuclear reactor), and Microwave Thermal Rocketry isn't particularly picky about the gasses you use for reaction mass (meaning the Propulsive Fluid Accumulator satellites could usefully collect *all* the gasses they passed through, not just the Oxygen fraction), you could easily just use Earth's upper atmosphere in its natural proportions for reaction mass on the Mars Mission (although you might want to filter out the Ozone due to its corrosive properties), so Microwave Beamed Power Thermal Rocketry has *GREAT* synergy with Propulsive Fluid Accumulator systems (both sharing the same beamed-power sources, and providing a use for almost 100% of the gasses available to the atmospheric scoops...)

Did I mention Methane (which can easily be manufactured on Mars from the atmosphere and small amounts of water-ice in the soil using the Sabatier Reaction) also works for Beamed Power Thermal Rocketry? (or Nuclear Thermal Rocketry as well) Though at that distance you're going to need to convert the Microwaves into a visible light Laser first so as to reduce transmission-losses all the way to Mars... (and you definitely won't have enough power available to run an electric engine off beamed power at those distances). You might even be better off packing a high-powered nuclear reactor to run the Sabatier Reactor on the surface, and equipping it with a gyrotron so it can beam its power output to the return-vessel to get back to Earth, when the mission comes to an end and the electricity is no longer needed for fuel-production or life support...

Even so, accelerating back towards Earth would probably take a bit over a month using Microwave Thermal Rocketry either way, due to transmission-losses over such vast distances, and the resultant very limited power-supply available from beamed power out by Mars... (if you packed a nuclear reactor equipped with a gyrotron, subsequent missions could also re-use that reactor if you packed a small satellite to orbit Mars and relay the power to the next landing site... If you also packed a new reactor with each mission, you could have a steadily increasing power-supply for ISRU and beamed-power rocketry on the return-voyage...)

Did I mention all of this is possible with TODAY'S science? Microwave Thermal Rockets, gyrotrons, Microwave relays, Sabatier Reactors- all of these things have been tested and demonstrated on a small scale on Earth. The difficulty is in engineers/researchers obtaining the funding to build scaled-up, high-performance versions for use in space...

If we used some of the more advanced mission-design concepts I mentioned here (like re-using a nuclear reactor packed for ISRU fuel-production for beamed-power propulsion on your return-voyage), we could easily have a man on Mars mission lifting off by 2038- which is probably about how long it would take to fully mature Microwave Beamed-Power and high-powered (multi-megawatt) electric engines to use that power if NASA got serious about both of them tomorrow...

Regards,

Northstar

Edited December 9, 2014 by Northstar1989

[cicatrix]

The question is - why would anyone want to land on Mars? If it's just a way to show off - I doubt it will be before 2050.

From the other hand, if the current situation is magically changed somehow and it becomes VERY URGENT and VERY IMPORTANT to put a man onto the surface of Mars (yes, a man, not a robot), I think it can be manageable before 2020-2025.

Practically though, there's very little a man can do there what a robot cannot. Modern world demands immediate economic benefits for anything. What's there on Mars we would want that badly?

[Northstar1989]

The question is - why would anyone want to land on Mars?

-SNIPPED-

Practically though, there's very little a man can do there what a robot cannot.

-SNIPPED-

What's there on Mars we would want that badly?

Answers about life beyond Earth. Our place in the universe. The future of mankind and our ability to eventually settle other planets in our solar system.

All of these things are IMMENSELY important goals- and humans can answer most of them MUCH more effectively than robots (whatever you may think, we're not nearly to the point of humanoid robots than can operate without remote-control yet... And even if we were, one of the goals is to discover if HUMANS can survive on other planets...)

Plus, humans have some nifty abilities robots will always lack for the foreseeable future- like the ability to repair themselves of minor injuries with nothing but food and rest, and the ability to maintain an entirely sealed-off, constant environment separate from the outside world (we call this process homeostasis in biology- and robots lack it. Even something as seemingly minor as Martian dust can cause problems with robots...) We're also much more nimble- which helps with things like repairing broken equipment (there's a reason we send humans and not robots to repair Hubble), and constructing a semi-permanent base. That's not to say humans are cheaper, or that robots CAN'T do these things- only that humans can do many of them better.

Ultimately, humans will attract more public attention, and are the more desirable option. We just need a way to get them there for a fraction of the total mission cost we currently can- which is where things like Microwave Beamed Power, magnetic launch-assist systems to get off Earth, Propulsive Fluid Accumulator Satellites, In Situ Resource Utilization, and Cycler Ships (look those up if you don't know what I mean- specifically I'm thinking of an Aldrin Cycler) come into play...

Regards,

Northstar

[kerbiloid]

Practically though, there's very little a man can do there what a robot cannot.

Because it's much faster to say: "Get a rover, go to that rock which we have discussed yesterday, and bring a bucket or two of ground from there" than to develop and test a software script doing the same.

Also if the human suddenly finds a nice-looking stone there, he just puts it into the bucket too.

Also to repeat this with another place you would just say: "All right, and now  to that rock too."

[cicatrix]

Answers about life beyond Earth. Our place in the universe. The future of mankind and our ability to eventually settle other planets in our solar system.

I do agree, but we're speaking here about the future more distant than the timeframe offered by the OP. Yes, in order to live on Mars like we do on Earth we would need to terraform it. Now, this is a GLOBAL project. But first, we need to overcome all environmental damage our civilization made here. We need to learn how to terraform things starting with Sakhara desert, for example, or Antarctica. Then we should start thinking about Mars and beyond.

All of these things are IMMENSELY important goals- and humans can answer most of them MUCH more effectively than robots (whatever you may think, we're not nearly to the point of humanoid robots than can operate without remote-control yet... And even if we were, one of the goals is to discover if HUMANS can survive on other planets...)

So, now, as a preparation, we're talking about a scientific experiment? Why wait for so long? Put a chimpanzee in an environment chamber representing the surface of Mars and see if it lives. We can experiment without actually getting there. It would be cheaper and safer.

Plus, humans have some nifty abilities robots will always lack for the foreseeable future- like the ability to repair themselves of minor injuries with nothing but food and rest, and the ability to maintain an entirely sealed-off, constant environment separate from the outside world (we call this process homeostasis in biology- and robots lack it. Even something as seemingly minor as Martian dust can cause problems with robots...) We're also much more nimble- which helps with things like repairing broken equipment (there's a reason we send humans and not robots to repair Hubble), and constructing a semi-permanent base. That's not to say humans are cheaper, or that robots CAN'T do these things- only that humans can do many of them better.

I agree that humans are more resourceful and creative, but I asked a different question: what's there on Mars NOW? What are the possible advantages of having a human there rather than Curiosity? Really, we're not speaking about a great achievement of the mankind, but about practical use?

[magnemoe]

The question is - why would anyone want to land on Mars? If it's just a way to show off - I doubt it will be before 2050.

From the other hand, if the current situation is magically changed somehow and it becomes VERY URGENT and VERY IMPORTANT to put a man onto the surface of Mars (yes, a man, not a robot), I think it can be manageable before 2020-2025.

Practically though, there's very little a man can do there what a robot cannot. Modern world demands immediate economic benefits for anything. What's there on Mars we would want that badly?

Yes, it would be smarter to send more robots, even sample return.

Downside of an manned mars mission is cost and biological contamination, after the mission it will be life on Mars so no need for more missions to search after it.

[prophet_01]

I don't rly expect NASA or any other govermental organisation to pull off a mars mission. The goverments lack continuous funding and will. ARM may or may not be cancelled, but a mars mission is a lot more expensive and requires further (pricey) development. The building of an extended infrastructure for easyer access to LEO and beyond is unlikely to happen soon. Goverments aren't even thinking about anything beyond a very limited number of manned mars missions. So it's rather pointless to commit to that kind of long term investment if there isn't a number of other projects would benefit from it.

The private organisations on the other hand lack a secure and continuous demand for manned flights, yet. Maybe that will changes within the next decades, although I doubt it All those mentioned technologies, even if they turn out to be reliable and cost effective, need massive investments. At the moment, nobody is willing to fund a skylon or full scale microwave propulsion system. The promised cheap access to LEO is not going to be developed without an economic reason that jstifies the risks of losing millions that are sunk in a "not as cheap as predicted" technology. I don't expect those highly experimental systems to be a part of a mission to mars within the next two decades. SLS + orion and a habitat module are sadly the best chance for it to happen at all for now (sadly refers to the chances, I like orion and SLS). It's not as likely to happen as I would like it to be, but to be fair: we haven't been this close to a manned mars mission ever (arguably since apollo)

However, I'm not too excited about it since it wouldn't change that much with regard to long term space exploration. It would be the same as it was with apollo. A great acomplishment for humanity of course, but it's one step ahead and two steps back. People lose interest shortly after the parades and what's left is the focus on smaller and more practical stuff in LEO

Edited December 9, 2014 by prophet_01

[Starman4308]

Because it's much faster to say: "Get a rover, go to that rock which we have discussed yesterday, and bring a bucket or two of ground from there" than to develop and test a software script doing the same.

Also if the human suddenly finds a nice-looking stone there, he just puts it into the bucket too.

Also to repeat this with another place you would just say: "All right, and now  to that rock too."

And yet it's much cheaper to send two entirely separate robots whose sole purpose in life is to pick up one rock each and carry them to a return rocket.

Stuff on Mars isn't moving anytime soon, and humans are extremely expensive. Difficulty and timeframe are much more solvable problems than trying to worm the funding for a manned mission out of Congress. A manned mission would be a wholly irresponsible waste of money: while the sciences should get more funding, the return rate on manned Mars missions would be poor.

[Nibb31]

Because it's much faster to say: "Get a rover, go to that rock which we have discussed yesterday, and bring a bucket or two of ground from there" than to develop and test a software script doing the same.

Also if the human suddenly finds a nice-looking stone there, he just puts it into the bucket too.

Also to repeat this with another place you would just say: "All right, and now  to that rock too."

What's the use of being "faster" ? Those rocks aren't going anywhere and isn't any particular emergency to get the data. The rover has literally all the time in the world. It doesn't have to return to the base every day to eat or sleep. It doesn't have limited oxygen or EVA time and it doesn't have to return to Earth at the end of the mission. One could argue that the MERs returned more science in 10 years than a manned landing could have returned in 1 month, for a fraction of the cost.

If anything, it's faster to send a rover now and have it pick up a rock in 6 months than to wait until we're ready to send a human pick up the same rock in 20 years.

Also, we can easily send hundreds of rovers to cover a much wider area over a much longer period. A human expedition would only last a couple of months and cover a limited range around the lander vehicle.

In terms of science returns, coverage is more important than speed. Geology certainly isn't a good enough reason to send humans to Mars.

Edited December 9, 2014 by Nibb31

[NASAFanboy]

I'm an optimist, so I will say 2035. Realistically, it could probably happen in that timeframe. I'm not going to discuss why we are sending a human to Mars instead of robots or the scientifically ramifications, since flags and footprints are apparently more useful to the US Congress than actual science; I'm not going to protest that.

For those who ask, the SLS/Orion is getting the funding that is being asked for; not only that, but Congress is asking for more money than the budget requests are allocating these projects in both Houses and political parties, and even passed a bill to prevent a future adminstration from cancelling them. No previous Mars project had such support, and Orion doesn't have to compete with the Shuttle for funds since it's retired or another foreign war. All said, I think we are allocating much less gratitude to Congress than they are owed. Sure, they aren't funding NASA to it's full potiental, but you can see an attitude shift towards pro-NASA than it had been in the past years.

Edited December 10, 2014 by NASAFanboy

[DunaRocketeer]

I don't think we'll see a Mars mission in any of our lifetimes, the best that I hope for these days is a rationalisation of the launch vehicle market: ULA and Arianespace are already reacting to what SpaceX are trying to do, and it could make launching satellites and space probes a bit cheaper. If there is to be progress in spaceflight, it will come from there, not from the likes of NASA. NASA can't afford to build the Orion service module, it isn't funding exploration systems for SLS. The budget is flatlining/declining relative to inflation. It's all a sure-fire way of getting the whole lot cancelled. My jaw will hit the floor if Orion/SLS becomes much more than a historical footnote, just like Constellation, OSP, X-33/VentureStar, Shuttle C etc etc.

The future of humanity seems to be more introspective, more virtual; we're creating a new type of society thanks to computer technology, that's where the revolution is - if I could go back to my 16 year old self in the year 2000, and showed him what the world would look like in 14 years, I think he'd be amazed. In 10, 20, 50, 100 years, I can see society being very alien to us, and that process will continue until we collapse the biosphere, drown in debt, destroy ourselves in resource wars or some combination of the above.

If there was an option in the poll for that, that'd be what I'd tick. If any beings from Earth ever do make it out to Mars, I think it'll be so far in the future they may as well be aliens.

[Overfloater]

Not before WW-III.

[Karriz]

If SLS + Orion get proper funding and nothing particularly special happens, I'll go with 2035-2039.

Then there's also SpaceX working on a reusable super-heavy lift rocket, but nothing is really known about that one. They could really change things.

[problemecium]

I sure do hope we get there by 2019, but, well... for one thing, we humans have been saying we'll go to Mars in 30 years for the last 50 years. And for another, a big part of the reason Interstellar was so compelling is because of its believability. A lot of us are looking away from our place in the stars and down at our place in the dirt. So sadly I won't be surprised at all if another 20 years go by with no manned Mars mission.

I can say with absolute certainty, however, that we will land on Mars on Monday. Which Monday I have no idea, but I'm willing to bet on the 1 in 7 chance that it happens on a Monday ;P Around 4:00.

[LABHOUSE]

By 2025 I think but possibly as early as 2018 and as late as 2038. Depending on what definition is used.

Edited December 9, 2014 by LABHOUSE

[Northstar1989]

The building of an extended infrastructure for easyer access to LEO and beyond is unlikely to happen soon. Goverments aren't even thinking about anything beyond a very limited number of manned mars missions. So it's rather pointless to commit to that kind of long term investment if there isn't a number of other projects would benefit from it.

I don't think you understand what exactly we're talking about here with regards to space-access technologies.

By their very nature, these technologies are MUCH CHEAPER than conventional rocketry. That's why they're worth building/developing. They're *not* a more expensive investment, as you insinuate- rather, they're actually a cheaper option for demand here an today.

Let's take the example of Microwave Beamed Power, for instance. If you can launch 100 missions a year with it, Microwave Thermal Rocketry becomes a MUCH cheaper alternative to chemical rockets.

That may sound like a lot of launches- but if the system is scaled to launch 1 ton of payload on each rocket or spaceplane, then that's in the range of support costs for the ISS, which required 60-100 tons of supplies a year before the installation of a Sabatier Reactor to reduce life support costs... (food, water, oxygen, station-keeping fuel, etc.) I think it's down to around 40-50 tons of supplies a year now- which is still nothing to sneeze at...

Microwave Beamed Power cost-scaling is at least linear or better- meaning a rocket with twice the payload capacity will be no more than twice as expensive (including cost of ground facilities and the rocket itself) with the same number of launches per year. Probably less so, as larger rockets have batter fuel-fractions and ballistic coefficients, both of which tend to bring down the cost-per-ton to orbit... Since the thermal engines are technically very simple (there is only one propellant, no combustion, and very few moving parts), it's extremely easy to scale them up to higher thrust levels without any of the engineering difficulties that drive conventional rockets to use engine-clusters instead of larger monolithic engines...

The private organisations on the other hand lack a secure and continuous demand for manned flights, yet. Maybe that will changes within the next decades, although I doubt it All those mentioned technologies, even if they turn out to be reliable and cost effective, need massive investments. At the moment, nobody is willing to fund a skylon or full scale microwave propulsion system. The promised cheap access to LEO is not going to be developed without an economic reason that jstifies the risks of losing millions that are sunk in a "not as cheap as predicted" technology. I don't expect those highly experimental systems to be a part of a mission to mars within the next two decades. SLS + orion and a habitat module are sadly the best chance for it to happen at all for now (sadly refers to the chances, I like orion and SLS). It's not as likely to happen as I would like it to be, but to be fair: we haven't been this close to a manned mars mission ever (arguably since apollo)

None of these technologies require MASSIVE investments to carry out on a scale usable for unmanned missions and satellites. A Microwave Beamed Power system capable of launching 1-2 ton payloads is QUITE cheap- much cheaper than existing conventional launch infrastructure, even after you include the research/development costs... A Microwave Beamed Power system using disposable rockets could pay for its own R&D costs, and facilities costs, within 5-10 years of completion if all it did was supply the ISS and launch a handful of small GEO satellites each year- which is quite impressive compared to any cutting-edge conventional systems (that's one reason we've been using some of the same launch vehicles for over 30 years...)

I haven't even scratched the surface when it comes to the cost-savings from reusable launch vehicles. A Two Stage to Orbit Microwave Thermal Rocket that re-uses its launch stage Space-X style, or better yet a 100% reusable spaceplane (with ISP over 800 seconds, and potentially *infinite* ISP in the lower atmosphere using Microwave Thermal Turbojets, Microwave Thermal Rocketry places spaceplanes squarely within the realm of possibility...) would reduce costs even further. Did I mention that, besides being highly reusable, a spaceplane can carry more payload to orbit than a rocket with the same amount of available beamed-power, due to the fact that spaceplanes can lift off and reach orbit with a TWR of much less than 1?

However, I'm not too excited about it since it wouldn't change that much with regard to long term space exploration. It would be the same as it was with apollo. A great acomplishment for humanity of course, but it's one step ahead and two steps back. People lose interest shortly after the parades and what's left is the focus on smaller and more practical stuff in LEO

NONE of the technologies I mentioned are geared solely towards high-energy manned missions. In fact ALL of them, including Skylon, Microwave Beamed Power, and magnetic launch-assist systems work BETTER with smaller payloads and more frequent launches.

It's much easier to build a spaceplane that can carry 2 metric tons to LEO in a single launch than it is one that can carry 12 or 20, and requires less beamed-power if you're utilizing Microwave Thermal Rocektry...

If you're using a magnetic launch-assist system, the launch tube can only provide a set amount of energy, and only to a rocket of a set size. For instance, Star Tram's first-generation design would be limited to 2.5 meter rockets massing no more than 40 tons on the ground (which amounts to getting 5-8 tons of payload to LEO thanks to the greater payload-fraction a magnetic launch-assist at multiple km/s enables...) Of course, as I've pointed out several times before, the most expensive Delta-V is the first few hundred m/s, with each m/s becoming cheaper as the rocket becomes lighter, due to the Rocket Equation. Comparing a system than can provide 1800 m/s to a rocket out the top of a mountain and one that can "only" provide 900 m/s, the less powerful variant is going to cost less than twice as much, while providing more than half the fuel and cost-savings... (BEFORE you even consider the thermal-management and aerodynamic-stability issues 1800 m/s in the lower atmosphere entails: which are manageable, as hypersonic aircraft already demonstrate, but add to cost and mass...)

Also, as I've pointed out several times, some of these systems can be combined for even greater cost-savings (such as Microwave Beamed Power and spaceplanes- as the company Escape Dynamics is attempting; or ISRU and Microwave Beamed Power, if you power the ISRU reactor with beamed-power, or with a nuclear reactor equipped with a gyrotron to beam power at the return-voyage...) None of these systems are unable to be utilized for resupplying the ISS and launching GEO comm satellites,but all of them can be scaled-up for cheaper manned missions to Mars ...

Regards,

Northstar

[fenderzilla]

I say when we get fusion power. fusion would help with all sorts of awesome space stuff like Thermonuclear Turbojets (which could be super great for SSTOs), much better NERVAs (because of more energetic reactors), and let's not forget that the invention of stable fusion power would need some pretty strong electromagnets, which could be used to shield from solar radiation.

[King Arthur]

I say when we get fusion power. fusion would help with all sorts of awesome space stuff like Thermonuclear Turbojets (which could be super great for SSTOs), much better NERVAs (because of more energetic reactors), and let's not forget that the invention of stable fusion power would need some pretty strong electromagnets, which could be used to shield from solar radiation.

The problem with nuclear fusion, and really anything that has the word "nuclear" associated with it, is that the public will mercilessly shoot it down immediately with extreme prejudice.

Nuclear technology can allow for many great things, but we're going to need to address the many years of nuclear fear-mongering most of the public has been subject to before we can even imagine putting nuclear technologies into normal use for something like spaceflight.

For what it's worth, RTGs haven't been shot down, but then it's hard for the general public to think of the word "nuclear" from just the three letters "RTG".