4 ms·

I mean, McDonnell Douglas had a working prototype already in the 90s: https://youtu.be/JzXcTFfV3Ls?t=76 https://youtu.be/JzXcTFfV3Ls?t=76

hef19898 6y ago
Damn, didn't know about that! Impressive thing!
andy_jensen 6y ago
So had Spectre in 1967 https://youtu.be/Dnaorqo6krg https://youtu.be/Dnaorqo6krg
himinlomax 6y ago
It was barely a prototype, more of a proof of concept, as it couldn't lift anything much but itself. Also it was not just reusable (though not reused) but SSTO. And SSTO is almost certainly a dead end for chemical rockets. In part but not exclusively because aerospikes seem to be impractical, but also because fully reusable and inexpensive boosters are obviously working just fine. The case for sending a lot of deadweight up the gravity well is simply too poor, even if you could do it with great efficiency.
- dingaling 6y ago
  A PooC seems a reasonable moniker, but the sole reason it didn't proceed to anything more practical was the lack of government funding. Big Space had become so dependent on gov contracts that they couldn't envisage doing anything on their own initiative: that was the true innovation of SpaceX, not landing rockets. Frankly Delta Clipper was even more impressive given that it came from MDC who were by far the most conservative defense contractor. That sort of thing would have been more typical of Northrop.
  - cheaprentalyeti 6y ago
    DC-X's followups didn't get funded because the government and its subcontractors were comfortable with the expendable rockets, at least until Boeing (which bought McD) got frozen out of most government contracts for the EELV program. They were "punished" for corporate espionage by the government giving the contract to the company with the expensive, important parts of the rocket built in Russia. (BTW, kids, if you ever want to see what a successful act of espionage looks like, look at this: it would look like Boeing shooting off its own foot and then the Pentagon shooting off its own foot in response, both in ways that "accidentally" benefit Russia and make us dependent on them for space access.)
  - cheaprentalyeti 6y ago
    Oh, and a quick non-political followup: Falcon 9 looks like another iteration of DC-X done with dense fuels in mind as per Mitchell Burnside Clapp's papers back in the 90's. I did a quick search but all that turned up was this. [1] I don't know what this says regarding the possibility of further success for SpaceX; they've moved to a less dense fuel in hopes that it'll allow them to have self pressurizing tankage. While SpaceX has had increadible success I find myself wishing there was a way of wedding Elon's money and drive with the people who built DC-X in hopes that they could maybe, MAYBE, get more than one or two flights out of each test vehicle. IF you could get cheap RL-10's for the price that the DC-X project was buying them for in the 90's, I'd suggest using them, suitably modified to burn methane, _just_ as a braking/landing engine. [2] (But that was way back in the 90's, when the MIC was still sometimes running assembly lines instead of building each single engine by hand). (Oh, and I found a slightly better ref. on RL-10's: [3]) [1] https://yarchive.net/space/rocket/fuels/hydrogen_deltav.html https://yarchive.net/space/rocket/fuels/hydrogen_deltav.html [2] https://forum.nasaspaceflight.com/index.php?topic=11020.0 https://forum.nasaspaceflight.com/index.php?topic=11020.0 [3] https://yarchive.net/space/rocket/rl10.html https://yarchive.net/space/rocket/rl10.html

hef19898 6y ago

Damn, didn't know about that! Impressive thing!

andy_jensen 6y ago

So had Spectre in 1967 https://youtu.be/Dnaorqo6krg https://youtu.be/Dnaorqo6krg

himinlomax 6y ago

It was barely a prototype, more of a proof of concept, as it couldn't lift anything much but itself. Also it was not just reusable (though not reused) but SSTO. And SSTO is almost certainly a dead end for chemical rockets. In part but not exclusively because aerospikes seem to be impractical, but also because fully reusable and inexpensive boosters are obviously working just fine. The case for sending a lot of deadweight up the gravity well is simply too poor, even if you could do it with great efficiency.

dingaling 6y ago
A PooC seems a reasonable moniker, but the sole reason it didn't proceed to anything more practical was the lack of government funding. Big Space had become so dependent on gov contracts that they couldn't envisage doing anything on their own initiative: that was the true innovation of SpaceX, not landing rockets. Frankly Delta Clipper was even more impressive given that it came from MDC who were by far the most conservative defense contractor. That sort of thing would have been more typical of Northrop.
- cheaprentalyeti 6y ago
  DC-X's followups didn't get funded because the government and its subcontractors were comfortable with the expendable rockets, at least until Boeing (which bought McD) got frozen out of most government contracts for the EELV program. They were "punished" for corporate espionage by the government giving the contract to the company with the expensive, important parts of the rocket built in Russia. (BTW, kids, if you ever want to see what a successful act of espionage looks like, look at this: it would look like Boeing shooting off its own foot and then the Pentagon shooting off its own foot in response, both in ways that "accidentally" benefit Russia and make us dependent on them for space access.)
- cheaprentalyeti 6y ago
  Oh, and a quick non-political followup: Falcon 9 looks like another iteration of DC-X done with dense fuels in mind as per Mitchell Burnside Clapp's papers back in the 90's. I did a quick search but all that turned up was this. [1] I don't know what this says regarding the possibility of further success for SpaceX; they've moved to a less dense fuel in hopes that it'll allow them to have self pressurizing tankage. While SpaceX has had increadible success I find myself wishing there was a way of wedding Elon's money and drive with the people who built DC-X in hopes that they could maybe, MAYBE, get more than one or two flights out of each test vehicle. IF you could get cheap RL-10's for the price that the DC-X project was buying them for in the 90's, I'd suggest using them, suitably modified to burn methane, _just_ as a braking/landing engine. [2] (But that was way back in the 90's, when the MIC was still sometimes running assembly lines instead of building each single engine by hand). (Oh, and I found a slightly better ref. on RL-10's: [3]) [1] https://yarchive.net/space/rocket/fuels/hydrogen_deltav.html https://yarchive.net/space/rocket/fuels/hydrogen_deltav.html [2] https://forum.nasaspaceflight.com/index.php?topic=11020.0 https://forum.nasaspaceflight.com/index.php?topic=11020.0 [3] https://yarchive.net/space/rocket/rl10.html https://yarchive.net/space/rocket/rl10.html