The thread for space cadets!

[Winner]

Interesting, things seem to be slowly moving in the right direction.

Esa study examines Skylon space plane

By Jonathan Amos
Science correspondent, BBC News

Skylon would use a recoverable secondary propulsion module to place a satellite in its final orbit

A consortium of companies will try to establish the business case for a reusable space plane in a new European Space Agency (Esa) funded study.

The concept under investigation is Skylon, a vehicle proposed by the UK firm Reaction Engines Ltd (REL).

Skylon would be powered by an air-breathing rocket engine that could enable it to take off and land at a standard runway.

Esa funding for the study is 1m euros (£0.9m).

It will run to the end of the year and will look at how a Skylon vehicle might operate in a market for satellite launches from the early 2020s onwards.

The research will be led by REL themselves. It will address the economics and some of the outstanding technical issues.

The latter includes examining the type of spaceport needed by the vehicle; and the team will visit French Guiana to see how a Skylon could fly out of Europe's existing launch facility in the territory.

There will be work done also to define more clearly the upper-stage carrier required for the Skylon concept.

As envisaged, the plane would fly to just above 300km and then release a secondary propulsion module to place a satellite in its final orbit. For telecommunications spacecraft, the main focus of the study, this would be at an altitude of 36,000km. It is an approach that was adopted by the US space shuttle in its early years.

Thales Alenia Space (TAS) of Italy will look at the specifications of this carrier, with assistance from Astrium Germany. The desire is to make it recoverable, so that after deploying the satellite, the propulsion module would return to Skylon to be brought back down to Earth for use on a later mission.

The contract for the Skylon-based European Launch Service Operator (Selso) study has been issued by Esa's launcher directorate, and draws funds from the agency's general studies and support budgets.

As well as overseeing work on Esa's existing rockets, such as Ariane, the launcher directorate is also constantly scanning the horizon for future launch technologies.

The agency's technical officer for the new study, Julio Aprea, told BBC News: "We are in full development of Ariane 5ME and have already started the development of Ariane 6 in Phase A, but we have to keep our eyes open. If the Skylon vehicle exists some day, it will be a game-changer for everyone."

A truly reusable space plane has the potential to significantly lower the cost of getting into orbit.

Although it would take billions of pounds to develop, such a vehicle offers the prospect of a reduced unit price per mission because of the frequency of use - in the same way as an expensive modern airliner can turn a profit.

Skylon would be an automated plane measuring a little over 80m in length and some 325 tonnes in mass. It would carry about 15 tonnes to low-Earth orbit.

Its key enabling technology would be REL's Synergistic Air-Breathing Rocket Engine (Sabre), which employs a very novel heat-exchanger to cool hot gases entering the engine intake.

The power unit would work like a jet at slow speeds in the lower atmosphere but then transition to full rocket mode at high speed in the upper atmosphere to make the jump to orbit.

Sabre is currently in development. It has been earmarked as a "high priority" technology project by the UK government following favourable technical reports from Esa's propulsion experts.

"At the end of the study we would like to have demonstrated the full business case for an operator, whoever that might be," said Mark Hempsell, REL's future programmes director.

"It would be an operator who has bought two Skylons, some upper-stages, some other equipment and flies out of Kourou in French Guiana. We have a market that is defined in the [study] requirements and our aim is to determine how much money this operator could make," he told BBC News.

As well as TAS, the consortium includes QinetiQ Space in Belgium and 42 Technology Limited in the UK. They too will look at various technical aspects. The London Economics consultancy will assess some of the main business issues.

​

 

[peter grimes]

I've never understood why the Sabre engines have a bent primary axis.

 

[Winner]

I've never understood why the Sabre engines have a bent primary axis.

I'll let Mark Hempsell, an employee of REL, answer that question:

Why a Curved nacelle? – the most frequently asked technical question. The answer is: the air intake on the front of the nacelle needs to point directly into the incoming airflow whereas SKYLON’s wings and body need to fly with an angle of incidence to create lift, so the intake points down by 7 degrees to account for this. The rocket thrust chambers in the back of nacelle need to point through the centre of mass of the vehicle so are angled down; again by 7 degrees but it is a coincidence the angle is the same.

The Intake is “shock-on-lip”, it means the intake swallows the shockwave from the intake cone (and the cone moves to ensure this happens) so all the air passing through the shock enters the engine nacelle, which in turn means we have more air than the engine needs for most of the supersonic flight regime. This is why we have a spill duct to dump the excess air thorough the burners, where we also dump the excess hydrogen used for cooling but not needed by the engine, and thus get a bit more thrust

Most supersonic aircraft intakes spill the air round the outside of the engine but this adds drag and means we cannot to the ramjet trick.

The Pre-cooler heat exchangers are the main technology under development at Reaction Engines and will be our hardware contribution to the vehicle. They are arrays of very fine thin walled Inconel tubes with cryogenic cooled helium gas through them, while the air flows outside the tube through the tube matrix. At Mach 5 goes from around 950 degrees C to around -140 degrees C with a total heat transfer of around 400 MW. The SABRE heat exchanger of made up of spiralling modules nested within each other like a Swiss roll helium entering from the inside and flowing outwards while the air counter flows inwards. It means the temperature difference between the air and the tube is never more than 10 degrees.

 

[hobbsyoyo]

I've never understood why the Sabre engines have a bent primary axis.

It looks to me like it's got an airfoil (wing-like) shape to it. The bent design probably helps the engine pod generate lift at low altitudes as the wings themselves are so small. I would also imagine the body of the system to be some sort of lifting-body shape as well. You'll also notice the insides of the engine pod are pretty much straight, that also kind of shows the shape of the pod's skin is an aerodynamic concern and not necessarily a structural necessity.

That thing is so long and skinny I hope it's autopilot is very good. I'd hate for it to smack it's tail on the runway....it's also going to need a very long runway I'd assume.

Edit: Goddamn it I was right but beat to the punch! Winner's post wasn't up there when I started writing this.

The tag at the top of this post is a misclick.

Edit 2: upon re-read it seems I was wrong and it's not for the pod to create lift (though I'm still saying it does) but for aerodynamic reasons to allow the intakes to breathe properly.

<nvm>

Come now, that was a great guess. One must not be afraid of being wrong! (otherwise I'd live in complete terror )

 

[peter grimes]

I'm glad I got to see Borachio's comment before he edited it

If this thing works it's going to be a major step forward for humanity.

 

[hobbsyoyo]

I've been playing around with the idea of beaming lots of power to a rocket which would then use the electricity to heat air into a plasma and shoot it out the back. You wouldn't have to carry much fuel because you'd gulp it up with intakes the way Skylon does and you don't even need to 'burn' any fuel until you are out of the atmosphere. It would be hyper-efficient and I know the military has been developing power-beaming systems. They have this idea of beaming down power to remote bases via satellite.

 

[Winner]

It looks to me like it's got an airfoil (wing-like) shape to it. The bent design probably helps the engine pod generate lift at low altitudes as the wings themselves are so small. I would also imagine the body of the system to be some sort of lifting-body shape as well. You'll also notice the insides of the engine pod are pretty much straight, that also kind of shows the shape of the pod's skin is an aerodynamic concern and not necessarily a structural necessity.

That thing is so long and skinny I hope it's autopilot is very good. I'd hate for it to smack it's tail on the runway....it's also going to need a very long runway I'd assume.

Edit: Goddamn it I was right but beat to the punch! Winner's post wasn't up there when I started writing this.

The tag at the top of this post is a misclick.

Edit 2: upon re-read it seems I was wrong and it's not for the pod to create lift (though I'm still saying it does) but for aerodynamic reasons to allow the intakes to breathe properly.

The more I read about Skylon, the more I have to marvel at their technical solutions. I love their philosophy - "we don't need to make an excellent, hi-tech packed spaceplane SSTO. One that flies to orbit with a significant payload and returns safely back to the airstrip is enough. We can always improve it later."

This is incidentally a reason why Skylon gets so much flak on American* forums - people just take a glance, don't read much about why things look the way they look and why they work the way they work, and start spouting nonsense about how it's impossible and how it's "common knowledge" that airbreathing rockets will never work, and blah blah blah. That, or they start suggesting "improvements" like removing the landing gear, making it an suborbital 1st stage of TSTO vehicle, stuff like that; which completely misses the point of Skylon - to make space travel more like air travel, with rapid turnaround, high reliability, and acceptable costs. The guys at REL (most having over 40-year aerospace engineering experience) have spent in excess of 25 years thinking about how to achieve the aforementioned goals and this is what they've come up with - the chance that a random guy on the internet will come up with a serious improvement after all of the 5 minutes he spent thinking about the same problem is ridiculously small.

Case in point, the host of the Space Show made some PRETTY inane comments, despite having had Hempsell twice on the show (really recommended to listen to those if you have a few hours to kill, or want to listen to something useful while jogging). He totally misunderstood the purpose of the vehicle and thought it to be a space tourism carrier or something stupid like that, and asserted that its business case is based on space tourism. REL has from the very beginning denied that and now ESA is going to fund a serious independent study trying to figure out if Skylon can really turn profit (they don't say that, but I imagine the mouths of many in Arianespace are watering thinking about what they could do with it); also, Skylon - if built - will for a long time fly in a purely automated mode. I'd say it would take many years, perhaps a decade, to prove the vehicle enough so that the operators would risk putting people in it (especially since it would carry as much as 30 people to orbit in one go, potentially risking a serious loss of life if it failed). I think it's likelier that manned flight will have to wait for Skylon Mk.2 or whatever they'll call it, which will be specially designed to be even safer and have more robust crew escape measures installed so that people can safely fly it to orbit.

---

* - (no offence here is intended, it's just my observation largely influenced by the fact that most forums where space is discussed are attended chiefly by Americans)

EDIT: Here's the 2009 interview with Mark Hempsell.
EDIT2: And here's the 2012 interview. They mostly cover the same topics, so I recommend the 2009 one.

 

[hobbsyoyo]

The host of the space show is exceedingly hostile to anything remotely non-traditional. I've been listening to the archives and he just bashes 'NewSpace' relentlessly. He did stick up for SpaceX a few times, but overall he's pretty hostile to the movement.

Haha no offense taken - every American that likes space stuff thinks of himself as the next Goddard, Von Braun or Korolev.

 

[Winner]

The host of the space show is exceedingly hostile to anything remotely non-traditional. I've been listening to the archives and he just bashes 'NewSpace' relentlessly. He did stick up for SpaceX a few times, but overall he's pretty hostile to the movement.

Well, he considers himself realistic, I'd say he's sometimes too cynical, and sometimes too optimistic about things he *should* be cynical about On average, he's pretty informed, but often stuck in one way of thinking which can be summed up as "if it doesn't make money in 4 years, it will never get anywhere". I am willing to accept that, but I don't like his "While I have the guest on the show, I will let him or her speak, but then later I will call his or her ideas stupid".

He has done literally that with the Dutch guy behind Mars One. Now, I share many of his reservations, I think Mars One really is a fantasy and I wouldn't bet a single Euro on it EVER getting anywhere close to Mars, but why doesn't he say it to the guest while he's on the air and can respond to the question?

Specifically, the Dutch guy said some less-than-informed things about technical details concerning landing on Mars and space travel stuff, and later he said that Mars One doesn't want people whose motivation is to "GTF off Earth". He also commented on the possibility of pregnancy among the early settlers, and said that they'd want to prevent that at all cost, and failing that, recommend an abortion because raising children in the early settlement would be too risky and costly. Livingston was all "uh-huh" and "okay", and a week later he literally calls the guy's comments "stupid" and "inane". His words exactly, I am not making this up.

I think that's unfair. If you think your guest is a wacko, just challenge him to answer satisfactorily while he's on air instead of badmouthing him later.

/irrelevant rant

 

[hobbsyoyo]

I actually heard where he called the Mars One guys inane and stuff. I had no idea they were on the show the week before. What an asshat.

Still enjoy the show.

 

[Winner]

I have read some stuff concerning SpaceX, and there are a few things that don't add up.

1) I talked about the reusability problem, if they want the first stage to fly back to the pad. I would say this would cost huge amounts of propellants, which would either require a substantially larger first stage, or a substantial reduction of payload. Now, Elon Musk claims the payload penalty for Falcon 9 "Reusable" would be "around 40 percent". I find that quite optimistic, like many things about the data SpaceX releases to the public (e.g. the dry mass fractions of their rocket's stages), but I'll trust him.

2) Now, I assume most of SpaceX's money-making business, besides government payloads, are to be geosynchronous satellites, i.e. payloads launched to a 185x35788 km geostationary transfer orbits (satellites then insert themselves in the final orbit upon reaching the apogee). We talked in this thread about how GEO satellites are getting heavier, in the 6-tonne range, possibly beyond, and how that influences the decision concerning Ariane-6.

3) According to this reliable source, Falcon-9 baseline (the version flown to date) has a payload of roughly 3.4 tonnes to GTO for a price of $35-55 million (I think this only includes the rocket, not the associated launch services, which could be substantial - but I may be wrong). Falcon-9 v1.1 which is the version SpaceX will probably operate commercially, has a GTO payload of 4.85 tonnes and costs $55-60 million. Note that 4.85 tonnes is still below the mass requirement for the next generation GEO satellites. This leads me to believe they want to launch heavy GEO satellites on Falcon Heavy, which, if crossfeed works, should lift about 19 tonnes to GTO for about $80-124 million. Notice that Falcon Heavy is beginning to approach Ariane-5 in cost (around $200 million).

4) If made reusable, the payload of Falcon-9 v1.1 drops to 2.9 to GTO due to the 40% penalty. Not enough for most current GEO satellites. Applying the same 40% penalty to Falcon Heavy, you end up with a vehicle of 11.4 to GTO capability, which is practically equal to that of Ariane-5 ME (which is set to be more powerful than today's Ariane-5 ECA, yet cost the same or be slightly cheaper). It is still cheaper, maybe twice as much due to limited reuse of its stages (that would, however, depend on the flight rates), but not nearly by "an order of magnitude" as the SpaceX fanboiz on the net say. This casts suspicion on Musk's confident comments on the BBC that Ariane-5 "has no chance" against his rockets. It seems to me it has a decent chance, especially if it keeps its very good reliability record. Falcon rockets still need to prove themselves in dozens of launches before reliability figures can be estimated with any accuracy. Plus, not everybody is allowed to launch on American rockets, so a segment of the customer base will likely continue preferring the European, Russian, or Chinese alternatives.

5) My main point here is this - reusable Falcon-9 v1.1 won't be able to service the main satellite market due to its low payload (it will be a cheap LEO alternative, though). Expendable Falcon-9 v1.1 will only be able to service a part of it. Most GEO satellites will have to launch on Falcon Heavy, which can only reuse (in the short term) its booster cores. The cost is not likely to be less than 50% that of Ariane-5, the premier vehicle for servicing the GEO market today, especially if it is upgraded and the price is pushed down a little.

6) Supplementary comment - I am of course assuming SpaceX would do double satellite launches on Falcon Heavy, which comes at the cost of scheduling and mating different payloads and all the other complications. If they were launching single sats only, the price per kg would end up the same as for Ariane-5.


So, where am I wrong? What did I miss that I don't see how totally revolutionary the Falcon rockets are and how they are gonna push all the existing launch vehicles out of the market?

(Final comment - I really wish SpaceX success. The more they push down price, the more they expand the satellite market, the more customers will there be when Skylon arrives )

---

Oh, Zubrin was on the Space Show again. This will be entertaining...

 

[Winner]

Soyuz explained. They used Orbiter for the animation!


Link to video.

 

[Kaitzilla]

Most supersonic aircraft intakes spill the air round the outside of the engine but this adds drag and means we cannot to the ramjet trick.

The Pre-cooler heat exchangers are the main technology under development at Reaction Engines and will be our hardware contribution to the vehicle. They are arrays of very fine thin walled Inconel tubes with cryogenic cooled helium gas through them, while the air flows outside the tube through the tube matrix. At Mach 5 goes from around 950 degrees C to around -140 degrees C with a total heat transfer of around 400 MW. The SABRE heat exchanger of made up of spiralling modules nested within each other like a Swiss roll helium entering from the inside and flowing outwards while the air counter flows inwards. It means the temperature difference between the air and the tube is never more than 10 degrees.

This sounds more complicated than a CPU fan or car radiator. I wish them luck!

 

[Winner]

This sounds more complicated than a CPU fan or car radiator. I wish them luck!

Well, I understand that the process of cooling the air itself so much so quickly isn't all that hardcore difficult. Had it not been for the frost problem, it would have been cracked decades ago.

The problems were centred around stopping the frost from clogging the pre-cooler (a major problem which REL claim to have solved *somehow*, that's their trade secret) and developing a method of producing and bending the little tubes which make the pre-cooler so that it can be manufactured on an industrial scale.

But I too find the notion that you can pack a 400 MW cooling machinery that would normally be the size of a medium power plant into a form compact enough to be put into a jet engine amazing. Humans can do magic-level tech if they're patient and persistent and intelligent.

(Now let's hope China doesn't steal it. I hear they're VERY interested in the technology...)

 

[hobbsyoyo]

(Now let's hope China doesn't steal it. I hear they're VERY interested in the technology...)

We'll know something is up when 'mysterious explosions' take down several small villages around their launch pads.

I have read some stuff concerning SpaceX, and there are a few things that don't add up.

1) I talked about the reusability problem, if they want the first stage to fly back to the pad. I would say this would cost huge amounts of propellants, which would either require a substantially larger first stage, or a substantial reduction of payload. Now, Elon Musk claims the payload penalty for Falcon 9 "Reusable" would be "around 40 percent". I find that quite optimistic, like many things about the data SpaceX releases to the public (e.g. the dry mass fractions of their rocket's stages), but I'll trust him.

2) Now, I assume most of SpaceX's money-making business, besides government payloads, are to be geosynchronous satellites, i.e. payloads launched to a 185x35788 km geostationary transfer orbits (satellites then insert themselves in the final orbit upon reaching the apogee). We talked in this thread about how GEO satellites are getting heavier, in the 6-tonne range, possibly beyond, and how that influences the decision concerning Ariane-6.

3) According to this reliable source, Falcon-9 baseline (the version flown to date) has a payload of roughly 3.4 tonnes to GTO for a price of $35-55 million (I think this only includes the rocket, not the associated launch services, which could be substantial - but I may be wrong). Falcon-9 v1.1 which is the version SpaceX will probably operate commercially, has a GTO payload of 4.85 tonnes and costs $55-60 million. Note that 4.85 tonnes is still below the mass requirement for the next generation GEO satellites. This leads me to believe they want to launch heavy GEO satellites on Falcon Heavy, which, if crossfeed works, should lift about 19 tonnes to GTO for about $80-124 million. Notice that Falcon Heavy is beginning to approach Ariane-5 in cost (around $200 million).

4) If made reusable, the payload of Falcon-9 v1.1 drops to 2.9 to GTO due to the 40% penalty. Not enough for most current GEO satellites. Applying the same 40% penalty to Falcon Heavy, you end up with a vehicle of 11.4 to GTO capability, which is practically equal to that of Ariane-5 ME (which is set to be more powerful than today's Ariane-5 ECA, yet cost the same or be slightly cheaper). It is still cheaper, maybe twice as much due to limited reuse of its stages (that would, however, depend on the flight rates), but not nearly by "an order of magnitude" as the SpaceX fanboiz on the net say. This casts suspicion on Musk's confident comments on the BBC that Ariane-5 "has no chance" against his rockets. It seems to me it has a decent chance, especially if it keeps its very good reliability record. Falcon rockets still need to prove themselves in dozens of launches before reliability figures can be estimated with any accuracy. Plus, not everybody is allowed to launch on American rockets, so a segment of the customer base will likely continue preferring the European, Russian, or Chinese alternatives.

5) My main point here is this - reusable Falcon-9 v1.1 won't be able to service the main satellite market due to its low payload (it will be a cheap LEO alternative, though). Expendable Falcon-9 v1.1 will only be able to service a part of it. Most GEO satellites will have to launch on Falcon Heavy, which can only reuse (in the short term) its booster cores. The cost is not likely to be less than 50% that of Ariane-5, the premier vehicle for servicing the GEO market today, especially if it is upgraded and the price is pushed down a little.

6) Supplementary comment - I am of course assuming SpaceX would do double satellite launches on Falcon Heavy, which comes at the cost of scheduling and mating different payloads and all the other complications. If they were launching single sats only, the price per kg would end up the same as for Ariane-5.


So, where am I wrong? What did I miss that I don't see how totally revolutionary the Falcon rockets are and how they are gonna push all the existing launch vehicles out of the market?

(Final comment - I really wish SpaceX success. The more they push down price, the more they expand the satellite market, the more customers will there be when Skylon arrives )

These are all valid questions and I have no good answer to be honest with you. This is part of why so many established aerospace figures are so skeptical of SpaceX. They do a tremendous job of stirring up excitement with slick PR CGI videos, but they do a terrible job of explaining how they'll do what they say they are going to do. Part of that is they want to protect trade secrets, naturally. But they still leave far too much for the imagination and for them to make such bold claims they need to have bold evidence.

Oh, Zubrin was on the Space Show again. This will be entertaining...

It was....okay. He only briefly went into excited-explosive mode but for the most part he stayed pretty grounded. It was worth listening to certainly.

Well, he considers himself realistic, I'd say he's sometimes too cynical, and sometimes too optimistic about things he *should* be cynical about On average, he's pretty informed, but often stuck in one way of thinking which can be summed up as "if it doesn't make money in 4 years, it will never get anywhere". I am willing to accept that, but I don't like his "While I have the guest on the show, I will let him or her speak, but then later I will call his or her ideas stupid".

My biggest problem with him is he so blatantly tries to have it both ways. When it suits him, he'll happily blast SpaceX and their 'mythical' rockets. He's extremely unfair when he goes into that mode and just rejects out-of-hand any objections.

Then, when it suits other goals, he happily explains why SpaceX and NewSpace and free market rah rah rah ARE THE BEST THING EVER.

He's not just playing devil's advocate either, he truly believes what he's saying, he just somehow skips over the mental disconnect between these two stances and it's quite annoying.

Another thing that you hit on with respect to the Mars One guys, he can be really rude. I like his show and he's very knowledgeable and connected but he can be a complete jackass on air to guests and people who call in.

I've been playing around with the idea of beaming lots of power to a rocket which would then use the electricity to heat air into a plasma and shoot it out the back. You wouldn't have to carry much fuel because you'd gulp it up with intakes the way Skylon does and you don't even need to 'burn' any fuel until you are out of the atmosphere. It would be hyper-efficient and I know the military has been developing power-beaming systems. They have this idea of beaming down power to remote bases via satellite.

There was a guest on from a company called Escape Systems that is building such a system and that got me excited. When I broached this idea with a professor he told me I was crazy! The difference between my mythical system and theirs is that they still bring propellent with them (H2), whereas I would scoop it out of the airstream and just use the nitrogen and oxygen as my propellant. I'm going to send him an e-mail and ask why they do that.

I had kind of hoped that if I could impress him he might offer an internship. However on the show he talked about how all his interns were from Yale and Caltech and MIT and such and I realized I'm never going to impress a snob who's stuck on only hiring from world-renowned schools. I don't really know that he is a snob, I think he was probably just showing off how awesome his company is. It was just disheartening to here him talk about it.

Well, I would have used them exactly in the Shuttle way - mount them to the side of the core stage, which would bear most of the load. But good points about the foam and other stuff - so scrap reusability, just drop them in the ocean. Or, at some payload penalty, carry some of them up into orbit and use them to build space stations


Link to video.

You're right about the thrust loading, I don't think it would be a problem. I also think the only reason NASA didn't drag their tanks to orbit to build a station with was safety. Which is funny considering how inherently dangerous (and how many astronauts were killed by) the Shuttle was. It was a huge missed opportunity in my opinion.

About engine reusability - I was surprised to read on astronautix and other sites that the Russians actually managed to produce large reusable engines, even though they operate at insane chamber pressures and temperatures, use oxygen-rich propellant mixtures and otherwise stress the engine components. Their RD-170 was apparently capable of withstanding up to 10-20 burns.

If the Russians have managed that with a kerosene engine more powerful than the F-1, I would *guess* that someone in the West who is prepared to spend some money and adopt some of the Russian know-how (which boils down to breaking a lot of stuff, until finally you make things that work not only well, but even excellently), it *should* be possible to design a powerful LH2/LOx engine capable of many consecutive restarts without extensive refurbishing after each flight. After all, this fuel mixture is pretty clean, so it doesn't clog with sooth or anything like that. It doesn't even have to be all that efficient; an Isp of over 420 s is acceptable, anything above only increases the payload.

I didn't know all that, I will have to look into it.

I've read in many sources that the aerospace industry is hopelessly conservative. They do things that they know work, but are very risk averse, which has been identified by many as the chief reason behind the lack of progress in launch vehicle developments. One of the main contributions of SpaceX so far in my opinion was to demonstrate that a judicious infusion of innovation into what's essentially 1960s era technology can lead to pretty spectacular results. Now imagine we went a little farther...

Yeah this is pretty much right. What's really crazy is that you wind up with this weird mentality where the industry is both conservative and intentionally ignorant of risks. What I mean is that you'll have companies stick with tried and true designs for decades and never innovate. On the other hand, when there is a problem with a vehicle, they can groupthink themselves into thinking it's all safe and ok. That's how we got 2 Shuttle disasters - and they were at least as much the fault of the industry contractors as they were NASA's fault. In particular, Thiokol knew the boosters were unsafe in freezing weather yet they let Challenger launch under those conditions.

It's a dangerous mix I think because a staunchly conservative* organization will refuse to acknowledge known risks and confront them head-on.

*I don't mean politically conservative, of course. However, I'd say most engineers in this field are very politically conservative, which is again wanting it both ways. They are more than happy that their companies suckle from the teat of government yet they hate the government and 'big government' in particular. Go figure.

(Oh, my proposal would definitely require government money, lots of it. The launch vehicle would be huge, beyond the ability of smaller companies to fund on their own. The bottom line is, I as a layman see no reason why this should be in principle impossible. Furthermore, even if SKYLON or Grasshopper or similar concepts work, we will only have reusable vehicles in the 10-20 tonne to LEO range. There will still be a need for heavy lift, if we are to go to Mars or build large bases on the Moon. It seems logical to me, then, that the US should, instead of going down the "big, complicated, expendable" route, focus on innovative concepts for achieving heavy lift. In the end, the initial investment would more than pay off later.)

Fair points.

Oh, he definitely *is* biased I am a Mars nut myself, so listening to his cruel reasoning isn't comfortable to me either, but I do have to (reservedly) agree with him. I ran a few simulations in my head and this is how it went:

Suppose for the sake of the argument that Zubrin catches a magic gold fish which grants him his wish to have Mars Direct implemented. OK, so the US invests the 50-100 billion dollars in a 10 year Apollo-style "let's go to Mars before this decade is out" dash and in mid-2020s first humans land on Mars. Then what?

The programme is far too expensive for the bean counters in Congress to sustain for long. Zubrin believes that once we get to Mars, everybody will be magically interested in keeping the programme running forever. But I think a much likelier scenario is that once the initial goals are met - we have men and women on Mars, planting flags, shooting videos for schoolkids, and doing science - the interest would quickly wane. It would get ordinary, like the ISS flights. Further Mars Direct missions would essentially be doing the same all over again, at least in the eyes of the public and their representatives in the American government. People would ask - what's the benefit for us here on Earth? What are the tangible gains to our economy, international standing, national security, etc.? Politicians would point out that nowhere in the space policy documents does it say that the goal of NASA is to colonize space, therefore using that justification is politically imprudent to say the least.

I actually have a slightly different view on how things will plan out but I'll admit my view is based more on optimism than hard facts. The way I see it is that society is in the midst of a second space age. All of the achievements of NewSpace and NASA are in the news quite a lot and rightly celebrated. There is also a lot more 'serious' science fictions stories of late. SciFi has always been a good backdrop for drama, but it seems that people are thinking about issues related to our expansion into space in a more realistic manner than they ever have before. I could be wrong, but I do believe that the public is really interested in space again.

So if there is a Mars landing or a moon landing or an asteroid mission, people are going to be really excited about it. Also, if MarsDirect ends up starting a colony, then I truly think the movement will be self-sustaining. To echo some of Zubrin's comments on his last Space Show interview, there are 7 billion people on this planet and a sizable fraction of them would go to Mars if they could and have the resources to do it if they were able to direct and pool their individual contributions. Once a Mars colony effort happens in earnest, there is going to be no stopping of it. It's going to happen because people like you and me are going to contribute and make it happen, if that makes sense.

Now if a Mars mission is a one-off thing and/or series of limited flights by governments, that changes the calculus a bit. One recent guest on the Space Show noted how even during the heyday of Apollo, public support was very low. So in that scenario I think enthusiasm could wane after an initial burst of excitement. But it is my hope that the space industry has matured enough that the capability will be there that will allow private citizens to follow up any government-led efforts on their own. That's the key difference between the Apollo era and space exploration of the near future in my opinion.

 

[Winner]

But they still leave far too much for the imagination and for them to make such bold claims they need to have bold evidence.

Fair enough, we'll see how it goes.

It was....okay. He only briefly went into excited-explosive mode but for the most part he stayed pretty grounded. It was worth listening to certainly.

Yup, I was positively surprised as to how lucid he was Although you could almost see his painful expression and gritted teeth when he talked about Mars One. I am sure that had it been "Moon One" or "Asteroid One" or any other destination other than Mars, he'd totally shoot them down, call them insane and just completely trash their case. But since this is Mars, he was only guardedly sceptical

Otherwise, nice thing they're going to do with the Mars 365 on Devon Island, and his comments about mobilizing people were pretty spot on. He should just watch the repetitive phrases he uses, they're quite grating ("the challenge that's been staring NASA in the face" etc.).

He's not just playing devil's advocate either, he truly believes what he's saying, he just somehow skips over the mental disconnect between these two stances and it's quite annoying.

You summed it up very well. I just listened to his first interview with Hempsell - he was absolutely supportive there, and praised REL's plan as being the most realistic he'd encountered so far. Fast forward to 2013 and he calls them wackos.

Maybe he's getting senile and just forgets things, because I don't see how else to explain it.

There was a guest on from a company called Escape Systems that is building such a system and that got me excited. When I broached this idea with a professor he told me I was crazy! The difference between my mythical system and theirs is that they still bring propellent with them (H2), whereas I would scoop it out of the airstream and just use the nitrogen and oxygen as my propellant. I'm going to send him an e-mail and ask why they do that.

Did he say why? I've heard about this approach to orbital launch before, and it doesn't strike me as implausible, although I don't think the technology is mature enough for that. Also, it would require quite the investment to set up the infrastructure.

Do you want to beam electricity, or just use lasers to heat up the reaction mass? Because the first option would obviously incur conversion losses, and probably increase the mass of the vehicle considerably. Also, you need to account for the drag losses, which, considering you spend a lot of time in the atmosphere since you're scooping gases out of it, might be significant. It all comes down to how much thrust can you realistically generate, and whether it is worth it as opposed to just carrying the reaction mass with you from the ground in the most convenient form.

I wish I hadn't lost my data, I had a few good articles about this in .pdf on my old HDD.

I had kind of hoped that if I could impress him he might offer an internship. However on the show he talked about how all his interns were from Yale and Caltech and MIT and such and I realized I'm never going to impress a snob who's stuck on only hiring from world-renowned schools. I don't really know that he is a snob, I think he was probably just showing off how awesome his company is. It was just disheartening to here him talk about it.

Yeah, I have a similar feeling when I am filling in job applications over here, although the fields are of course totally different.

I actually have a slightly different view on how things will plan out but I'll admit my view is based more on optimism than hard facts. (...snipped for brevity...)

I am oscillating between optimism and cynicism, so it's difficult to say what my position is precisely. Okay, I'll try anyway:

I think that Mars missions viability depends on the interplay of two factors:

a) people really want to go there, it's the place which is GENERALLY, even among people who don't care that much about space, seen as the logical next step after Moon.
b) it's very hard to do and it doesn't leave much in terms of benefit for Earth (except the usual industrial spin-offs and all the usual benefits stemming from investing in STEM - pun not intended).

If we really are at the beginning of a new space age, it will be a space age where companies and private space plays much bigger role than before. The government agencies will of course have to lead the way, because only they have the necessary know-how and experience with spaceflight, as well as the infrastructure to support it. Anyway, the point is, there will need to be some tangible payoffs.

As I see it now, there are two way of getting to Mars. One is the direct route (pun intended), ignoring everything else, and it depends on goodwill to keep it going. Simply put, it would be Earth charity towards people who want to go and live there. And charity can cease at any point, when the problems at home get serious.

The second route is to incrementally build up space infrastructure and capabilities in such a way, that eventually going to Mars won't even be that big of a deal. It will be a logical, relatively easy next step for a civilization that already is spacefaring. Since many subject, public and private, will already have established themselves in space, there will be more people capable of making the Mars dream a reality, as opposed to today when they'd first need to develop the entire mission infrastructure themselves.

---

Right now, I am beginning to lean towards the second, because I believe it will ultimately get us to Mars safer, on a permanent basis, and maybe even quicker. Apollo-on-Mars seem to me as more risky in terms of its possible cancellation before the goals are even achieved. So, if it was up to me, I'd go like this:

a) reduce cost of LEO transfer through promoting competition among PRIVATE operators of space launch systems. Support groundbreaking/innovative concepts with enough public money to give them a chance.

b) promote reusability/serviceability in the satellite market. Hire companies to get rid of dead satellites and repair/service those which can still function. Once the cost of servicing GEO satellites is lower than launching a brand new one, people will start buying such services.

c) Go to the Moon, start making propellant there. Even if it's just oxygen from lunar rocks. Send propellant back to depots in L1/L2, LEO or GEO. Investigate what can we economically build on the Moon or in space using lunar materials.

d) The same as above with asteroids, but mostly robotically.

e) Promote space tourism, including silly stuff like orbital amusements parks for the rich and bored. If we can squeeze some money from the filthy rich to fuel the cause of space exploration, so be it.

f) Hire companies to conduct deep-space robotic exploration for existing space agencies at lower costs; so while ESA and NASA focus on difficult, high-risk missions, commercial probes can visit dozens of asteroids, be put into orbits of Mars, Venus, or the outer planets, and investigate matters of importance. Companies will then sell data and samples to the space agencies. Science for money.


There will be a snowball effect to all this, with every step enabling the next step, but also feeding back to the previous step. As the demand goes up, I find it EXTREMELY UNLIKELY nobody would find a way to get to LEO reasonably cheaply. Skylon proves that if you're smart, you can do SSTO space planes. Others might go in completely different directions - big dumb rockets, space elevators, tethers, launch loops, giant guns, metallic hydrogen fuel, anti-gravity, who knows what's possible?

At some point, the infrastructure in space is so robust that when a guy with enough money, or a space agency, say "OK, I think we can try going to Mars, it won't cost that much if we can buy 70% of the stuff we need for the mission from companies which already operate in space."

And once that starts, it will be just another step towards truly spacefaring future for humankind. Cis-Deimos space around Mars will get developed just as the cis-Lunar space around Earth. And from Mars, we can expand to the Main Asteroid Belt. And from there, the moons of Jupiter and Saturn. And from there, eventually, other star systems. At that point, even if Earth goes down because of how we treat it, humankind will survive and still continue to expand it space. But without taking this step by step, any failure can mean we remain stuck on Earth forever.

(I apologize for typos and mistakes, but I have not time to proofread this properly.)

 

[Winner]

Oh, I found it again:

LEO on the Cheap

-> Excellent read. It is slightly technical, and I am sure I posted it in this thread or somewhere similar before, but if you want to know about conservative aerospace industry and why ICBM-heritage makes space launch so damn expensive, this is where you go for answers.

 

[Winner]

Elon Musk has unveiled his "Hyperloop" concept

-> So, if I understand it correctly, it would be a low pressure tube, inside which small bullet-like pods with passengers would be moving on an air cushion (like hovercraft) at near-supersonic speeds. The pods would be accelerated by an electromagnetic catapult at the start of the journey (and decelerated at the end), after which an onboard air compressor powered by an electric motor would counteract the air resistance and keep the capsule going. The walls of the tube would be covered by solar panels, generating enough electricity for the "Hyperloop" to be essentially self-powering. Since the tube itself is low-tech (unlike maglev tracks which are horrendously expensive), the cost of the proposed system between San Francisco and Los Angeles should be in the range of about 6 billion US dollars.

Cute idea, worth trying out. Musk said, however, that he has no plans to actually build it, he just wants others to pick it up (and buy his electric motors and batteries ).

 

[peter grimes]

your link has an extra "l" on the end.

http://www.spacex.com/hyperloop

 

[Winner]

your link has an extra "l" on the end.

http://www.spacex.com/hyperloop

Oops, sorry about that. Any comment on the idea itself?