50 Years of Progress in Launcher Design

Skipjack · Post by **Skipjack** » Sun Oct 07, 2012 4:11 pm

Part of the depot thing is orbital replenishment in general. Any kind of sustained effort beyond LEO can't be killing a launcher stack on a one way ship like Apollo did. If you're gonna reuse a ship of any kind eventually, you'll eventually need to develop the technologies and techniques for transferring fuel and supplies to ships permanently in orbit.

Considering that sustained effort will require depots, how long do you wait before investing in them? Start now and you end up with a fairly mature technology when you really get busy with it.

I totally agree with you on that one. We should focus on building an infrastructure and on doing that for less money, before we do anything else. Propellant depots are a very important part of that and we should start doing that soon.
The other part is cheap access to orbit.
If SpaceX really lowers the cost of a seat to the ISS by a factor of 100 (as they want to do), it would only cost 500k per person. That would mean that for the cost of the SLS, the US could send thousands of americans on a trip to orbit. Now that would be a spaceprogram! I think that this would give NASA a publicity boost and put space back on the map in politics (and not just as a government jobs program). People usually only care about things that directly affect them. With space being out of reach for the wast majority of US citizens, it has fallen into the category of "other things are more important". Bring it back into peoples lives and it will become more popular and it will have more political and financial support.

93143 · Post by **93143** » Mon Oct 08, 2012 12:15 am

Okay, Grasshopper does definitely seem to have left the ground, though not by much. SpaceX's video feed for tonight's launch showed three different angles, and the feet clearly lifted off.

One technical quibble laid to rest.

Skipjack · Post by **Skipjack** » Mon Oct 08, 2012 12:18 am

Okay, Grasshopper does definitely seem to have left the ground, though not by much. SpaceX's video feed for tonight's launch showed three different angles, and the feet clearly lifted off.

One technical quibble laid to rest

Told ya so

I know it was not much, but it is a start. It is at least someone even trying to do an RLV... It may be a bit underwhelming for now, but I take what I can get

Skipjack · Post by **Skipjack** » Mon Oct 08, 2012 1:06 am

Congrats to SpaceX! Dragon is in orbit and on its way to the ISS!

GIThruster · Post by **GIThruster** » Mon Oct 08, 2012 1:15 am

Now wouldn't it be cool to do that once every 3 days? Or instead we can have SLS. . .

Skipjack · Post by **Skipjack** » Mon Oct 08, 2012 1:57 am

Now wouldn't it be cool to do that once every 3 days? Or instead we can have SLS. . .

LOL, yeah. You know it is a shame that it is not NASA, but a small company like SpaceX that makes me dream about space exploration again.

kunkmiester · Post by **kunkmiester** » Mon Oct 08, 2012 4:52 am

LOL, yeah. You know it is a shame that it is not NASA, but a small company like SpaceX that makes me dream about space exploration again.

Years ago I'd have agreed. Having become so much more classic libertarian, I'd say it's wonderful that a private company is finally doing this.

As has been stated, SpaceX is using incremental advances of old technology. What they're doing could have been done in the 80s, maybe even the 70s. Imagine what things would be like if we'd done this then.

GIThruster · Post by **GIThruster** » Mon Oct 08, 2012 6:19 am

Truthfully, advances in composites since the failure of X-33 have made lithium aluminum second choice. Metal is not only more expensive but composites now perform better. What we had planned to do with X-33 we could do now, all save the trouble with the aerospike's heat sink. But I think there is a truncated aerospike that solves that problem too. As I recall 93143 just mentioned it the other day.

It's certainly possible to build better stuff than what people fly today. The trouble is we don't try. The last attenpt was with X-33 and that was bungled so badly no one has dared risk so much again.

And just saying--this notion that X-33 was too radical is not the reason it failed. It failed for 3 reasons. It failed because the people responsible for the original design did not understand the limitations of composite construction and so designed a tank that required seams that eventually made its weight skyrocket. It failed because the people doing the composite constructuion had no experience with composites and what they were attempting was at that time cutting edge. It also failed because the aerospike people wanted their contribution so much that they didn't admit they had the severe weight problem with the need for a heat sink until way too far into the project. All three of these issues could have been handled differently and the technology would have been proving itself for years by now. Even without funding, N-G went on to prove the technology necessary to build the enormous composite tanks necessary for H2 SSTO.

Be it vertical or horizontal landing, we have the technology today to build an SSTO launcher. We are building SLS instead. Without real leadership in the White House or at NASA, we can expect nothing but dreary nonsense like SLS. That's why I said NASA has made itself irrelevant. It is a dying institution (so far as HSF goes) for lack of vision and common sense, for surely any path that makes spaceflight so expensive it is unsustainable lacks common sense.

paperburn1 · Post by **paperburn1** » Mon Oct 08, 2012 10:24 am

Another problem that has an easy solution is durable cargo launch. We have put aside the concept of some cargo can be launched from A "super gun/ rocket combination". Water , foodstuffs, oxygen are not that G sensitive and could be launched that way. (SHARP) The bore diameter increases has a value of lowering the G forces on launch to the point of electronic guidance survivability.
as well as rendezvous tech has increased exponentially from the time that these ideas were looked at for viability. I think a step back would possibly bring some good results. As long as we get supplies and building materials up to our "Depot" at a cheap cost then the hauling the human element and "delicate equipment" could be done at the higher cost transportation. some number crunching puts payload costs down to hundreds of dollars per Kilo including launch faculty cost.
http://en.wikipedia.org/wiki/Super_High ... ch_Project

Skipjack · Post by **Skipjack** » Mon Oct 08, 2012 11:58 am

I'd say it's wonderful that a private company is finally doing this.

Oh, dont get me wrong! I am happy about them doing it. I meant it is a shame for NASA that it is not them doing it, but SpaceX...

GIThruster, the X33 had quite a few problems, one of them was Lockheed doing it.
I thought that both other designs would have been better. I also still think that they should have tried something less ambitious for a first RLV. Maybe a crew transport only, just enough payload to bring 7 people (or the equivalent in cargo) to the station.
The biggest problem was the funding though. The X33 was only the suborbital test vehicle (which means that it was nothing more than what the Lynx will be). The orbital Venture Star that was to be based on it, would have cost many billions more and was even further away from ever becoming reality. E.g. the compisit tanks would have had to be even bigger (and they already had problems with the small ones).
The whole project was just bodged from the beginning and yes I am still sour that they killed the DC-X for that...

KitemanSA · Post by **KitemanSA** » Mon Oct 08, 2012 12:18 pm

Is it odd that DC-X was going so well under Airforce hands and then crapped out so immediately when turned over to NASA?

GIThruster · Post by **GIThruster** » Mon Oct 08, 2012 3:18 pm

paperburn1 wrote:Another problem that has an easy solution is durable cargo launch. We have put aside the concept of some cargo can be launched from A "super gun/ rocket combination".

That's because it's not a practical concept. The wear and tear on both the launcher and the projectiles makes this a non-starter. What you end up with is a system that costs more than rockets by far, and all the expense is up front. That's why stuff like this never gets built, same as the laser launcher concept. It's simple economics.

GIThruster, the X33 had quite a few problems. . .The biggest problem was the funding though.

It already had plenty of funding and the political support of a very popular POTUS. The problems were the three I mentioned. The size of the tanks is not an issue. Both the Venturestar and the X-33 have tanks so large that it is not practical to put them in an autoclave, so composite design that does not require an autoclave is required. There is/was no significant difference in the construction needs of the two and as stated, Scaled Composites/N-G have developed a way to build these structures reliably for use with either horizontal or vertical landing designs. What was research back in the day is now researched.

paperburn1 · Post by **paperburn1** » Mon Oct 08, 2012 6:43 pm

GIThruster wrote:
paperburn1 wrote:Another problem that has an easy solution is durable cargo launch. We have put aside the concept of some cargo can be launched from A "super gun/ rocket combination".

That's because it's not a practical concept. The wear and tear on both the launcher and the projectiles makes this a non-starter. What you end up with is a system that costs more than rockets by far, and all the expense is up front. That's why stuff like this never gets built, same as the laser launcher concept. It's simple economics.

Most of the data design work was done in the 60,70 and revisited by SHARP in the 90s. It is now 2012 and great advanced have been made in the past 20 years. I am just saying it would be a good idea to revisit the concept and see if anything may have made a difference. It may still turn out to be unobtainable but I still think its worth a look.

GIThruster · Post by **GIThruster** » Mon Oct 08, 2012 7:00 pm

Most of the data design work was done in the 60,70 and revisited by SHARP in the 90s. It is now 2012 and great advanced have been made in the past 20 years. I am just saying it would be a good idea to revisit the concept and see if anything may have made a difference. It may still turn out to be unobtainable but I still think its worth a look.

The bulk of the data you want access to is classified as it's part of the Navy Railgun project. Even with the access aside, the point remains that such macro-engineering projects require all their multi-hundred billion dollar funding up front. These kinds of projects no matter how promising never get built. Instead of proposing one throw money at solutions that are not economically feasible, I heartily recommend funding very low cost exploration technologies that offer far greater financial rewards.

For instance, in order to step up M-E research and hope for thrusters that can enable a real space drive for human spaceflight, what is needed is primarily the power systems to run COTS materials. Any PhD EE who is good at his game can design and build such a power system in less than a year, so funding for an entire such program is less than $300k for the entire research program. For that kind of money we can have answers. For $3M, one could fund ten such independent explorations researching 10 different approaches. When so much information can be had with so little investment, why even consider hundred-million dollar investments that ought to become obsolete before they can be completed?