Quote from: Robotbeat on 11/18/2015 12:52 amA lot of that "heat" was my fault.HMXHMX, what are you up to? BTW, do you have a nice summary document of DC-Y/DC-X or any of the other high-mass-fraction vehicles you worked on?Unfortunately, as usual, I can't comment on my current work except to say it isn't SSTO. Close, though. But in response to the document request, I can only offer up an ancient paper:http://www.spacefuture.com/archive/history_of_the_phoenix_vtol_ssto_and_recent_developments_in_single_stage_launch_systems.shtml Note especially the appendix:http://www.spacefuture.com/archive/a_single_stage_to_orbit_thought_experiment.shtml I probably should finish up the book draft I started around 1992 (Single Stage: The 30 Year Quest for the Reusable Spaceship). It's only half done since I put it on the shelf about 1993 or so, and I have no idea if I'll ever re-write it, since now it needs to be renamed "...The 60 Year Quest..."
A lot of that "heat" was my fault.HMXHMX, what are you up to? BTW, do you have a nice summary document of DC-Y/DC-X or any of the other high-mass-fraction vehicles you worked on?
Quote from: HMXHMX on 11/18/2015 03:28 amQuote from: Robotbeat on 11/18/2015 12:52 amA lot of that "heat" was my fault.HMXHMX, what are you up to? BTW, do you have a nice summary document of DC-Y/DC-X or any of the other high-mass-fraction vehicles you worked on?Unfortunately, as usual, I can't comment on my current work except to say it isn't SSTO. Close, though. But in response to the document request, I can only offer up an ancient paper:http://www.spacefuture.com/archive/history_of_the_phoenix_vtol_ssto_and_recent_developments_in_single_stage_launch_systems.shtml Note especially the appendix:http://www.spacefuture.com/archive/a_single_stage_to_orbit_thought_experiment.shtml I probably should finish up the book draft I started around 1992 (Single Stage: The 30 Year Quest for the Reusable Spaceship). It's only half done since I put it on the shelf about 1993 or so, and I have no idea if I'll ever re-write it, since now it needs to be renamed "...The 60 Year Quest..." You never stopped since, what, the late 60's ? I wish you publish that book someday.
Quote from: HMXHMX on 11/19/2015 04:46 pmSince 1969, yes.Thanks for the vote, along with the four other people who want to read it, that makes five. Make that 6
Since 1969, yes.Thanks for the vote, along with the four other people who want to read it, that makes five.
As John Goff said QuoteI think the case of exoatmospheric suborbital refueling will likewise be one of those crazy things that we wonder how we ever lived without.
I think the case of exoatmospheric suborbital refueling will likewise be one of those crazy things that we wonder how we ever lived without.
Quote from: Archibald on 11/19/2015 04:30 pmQuote from: HMXHMX on 11/18/2015 03:28 amQuote from: Robotbeat on 11/18/2015 12:52 amA lot of that "heat" was my fault.HMXHMX, what are you up to? BTW, do you have a nice summary document of DC-Y/DC-X or any of the other high-mass-fraction vehicles you worked on?Unfortunately, as usual, I can't comment on my current work except to say it isn't SSTO. Close, though. But in response to the document request, I can only offer up an ancient paper:http://www.spacefuture.com/archive/history_of_the_phoenix_vtol_ssto_and_recent_developments_in_single_stage_launch_systems.shtml Note especially the appendix:http://www.spacefuture.com/archive/a_single_stage_to_orbit_thought_experiment.shtml I probably should finish up the book draft I started around 1992 (Single Stage: The 30 Year Quest for the Reusable Spaceship). It's only half done since I put it on the shelf about 1993 or so, and I have no idea if I'll ever re-write it, since now it needs to be renamed "...The 60 Year Quest..." You never stopped since, what, the late 60's ? I wish you publish that book someday. Since 1969, yes.Thanks for the vote, along with the four other people who want to read it, that makes five. Now if I could just find 50,000 more. Someday.
I personally think the conventional wisdom against SSTO RLVs is oversold. Technically speaking I think they're completely feasible, the tech necessary is high-enough TRL to be believable. We just haven't proven markets that need flight rates high enough for them to shine compared to expendable TSTOs yet.~Jon
Quote from: Archibald on 11/17/2015 05:41 pmAs John Goff said QuoteI think the case of exoatmospheric suborbital refueling will likewise be one of those crazy things that we wonder how we ever lived without. I'm not entirely sure how serious I was when I wrote that comment. There may have been some tongue-in-cheekage going on. Not that the idea is 100% stupid, just a bit crazy.~Jon
Do you think there is a launch rate that makes spaceplanes (HTOL) more efficient than a F9/Dragon rocket and capsule? Not sure SpaceX could cycle SLC-39A in less than 24 hours.
To, me, it's not a launch rate function, but rather a cost to orbit function. Once the cost is right, the market will take care of the rate.
I asked an astronaut a related question;QuoteDo you think there is a launch rate that makes spaceplanes (HTOL) more efficient than a F9/Dragon rocket and capsule? Not sure SpaceX could cycle SLC-39A in less than 24 hours.And Dan Tani repliedQuoteTo, me, it's not a launch rate function, but rather a cost to orbit function. Once the cost is right, the market will take care of the rate.He's probably right...
What about a 1.5 stage-to-orbit spaceplane with boom refueling after take-off? SR-71 style... take off with half-tank, then refuel. Not exoatmospheric, but has benefits.
I was enthusiastic for SSTO in the 90's, especially Delta Clipper. But I also remember some who said it wouldn't work back then. In the light of subsequent history I've (reluctantly) changed my opinion and now think that TSTO is the way to go.
I personally think the conventional wisdom against SSTO RLVs is oversold. Technically speaking I think they're completely feasible, the tech necessary is high-enough TRL to be believable. We just haven't proven markets that need flight rates high enough for them to shine compared to expendable TSTOs yet.
I am wondering whether TSTO RLVs are needed as an intermediate step so the market has time to gradually grow and adjust to the lower prices. Then we can move on to SSTOs in an attempt to lower launch costs even further.
Until someone can come up with a near nuclear level, compact, safe, self contained, low mass, power supply that can provide enough power to make a significant change to the mass ration to orbit, (higher than 10% of total mass) it is very unlikely that we will see any true SSTO or lifting body designs in any viable use.With current technology, it SHOULD be possible to make a SSTO design, so long as you are trying for Low Earth Orbit and NOT trying to reuse the rocket.