Podcast #128: We chat with Kent C Dodds about why he loves React and discuss what life was like in the dark days before Git. Listen now.
33

It’s a sense of scale issue. As much as the struts might look like flimsy bits of drainpipe, those rockets are around 15 meters wide, and the struts are more like the heavy steel beams used to hold up entire buildings. So yes, they’re just really strong.


29

What actual engine are they talking about Organic Marble has identified it as the S5.2/9D21. in what way is it "not a very good missile engine"? It uses a propellant combination, kerosene/IRFNA, common for military missiles in the 1950s-1960s, but now considered obsolete, which yields a poor specific impulse (233 seconds at sea level, or effective ...


24

Why hasn't the small-lift launch vehicles completely replaced by the medium and heavy-lift launch vehicles? Because small launchers can provide several things: A small launcher is much cheaper than using a large launcher to launch a single small satellite. a dedicated launch, instead of having to share a launch which reduces your choice of final orbits a ...


22

For Delta IV Heavy, according to Spaceflight101: The CBCs functioning as boosters are attached to the central core using thrust struts that interface with the interstage section of the launcher to transfer loads from the boosters to the rest of the vehicle. Additional attachment points reside in the base of the vehicle right above the engine heat shields. ...


21

Rockets (even old designs) are capable of delivering a nuclear weapon anywhere on Earth. Governments don't want this technology to fall into the wrong hands. Publishing a design takes a lot of effort. The complete design for a rocket easily exceeds a million drawings and hundreds of thousands of pages of supporting documents. For an old rocket, all of that ...


19

The NASA Spaceflight article Japanese sounding rocket claims record-breaking orbital launch describes JAXA's use of its SS-520-4 sounding rocket to put the Tricom-1R cubesat (43201, 2018-016A) into orbit. While there was an issue related to communications during the ascent, the satellite is currently in a 1572 x 189 km orbit. This is probably the smallest ...


19

Supplemental answer: Scud missiles were powered by the S5.2/9D21 engine, burning inhibited red fuming nitric acid and kerosene. Thrust is 132 kN, Isp is "2285 Nskg" or ~233 seconds. Sources: 1,2,3


18

I've tried to write it down, but then I've changed it into the following scheme. That way it is much cleaner. Note that the scheme doesn't include the recent Soyuz-2.1v vehicle. It seems like it is not "based" on R7 anymore. The conic boosters and core stage of R7 are no longer present.


17

Rockets can use different systems for attitude control (control thrusters, fins, gyroscopes, TVC, ...). Since you ask for the seconds after liftoff, the relevant system is TVC (Thrust Vector Control). TVC basically means that the engines themselves can gimbal to change the direction of the thrust. This can influence the attitude of the rocket by inducing ...


15

Juno 1 had a payload of 11 kg to LEO from a start mass of 29 t. Diamant-A had a start weight of 18.4 t, payload 100 kg to LEO. Black Arrow had a start weight of 18.1 t, payload 100 kg to LEO. Vanguard, start weight of 10 t, payload 9 kg to LEO. Lambda 4S had a start weight of 9.4 t, payload 26 kg to LEO. Caleb was an air-launched missile ...


15

Suborbital sounding rockets cost about 1/100 as much as an orbital launcher. Black Brant XII, one of the most advanced sounding rockets in use, can take 100-400kg payload into space for \$600K. For a Falcon-9-based sounding rocket approach to make any sense, you'd have to describe a single payload that delivered as much science as 100 individual 100kg ...


15

They already have one. The Falcon 9. Earlier this month a single Falcon 9 put 64 smallsats on orbit. It was arranged by a rideshare company, Spaceflight, at prices that small launch vehicles would have a hard time competing with, starting at \$300,000.


14

Really what it means is "Category 3" certified, with an additional review of a self-destruct situation to prevent breaking the nuclear payload. Category 3 is also what is required to launch humans, and in fact the final milestone in the Commercial Crew is to rate the system Category 3. It is required for any kind of sensitive launch. Note that man rated ...


14

While I have no specific knowledge of Falcon 9's fairing, it is common for compartments of space vehicles to be purged or pressurized slightly above ambient while on the pad to keep contamination out of the vehicle. After launch, vents allow the pressure in the compartments to drop in a controlled fashion as ambient pressure drops. To get a feel for how ...


14

Apparently lining up a lot of smallsats for a dedicated big rocket launch is like herding cats. Delays on any of the smallsats delay the overall launch. Hence SpaceX's recent announcement that their planned Falcon 9 dedicated smallsat launches will launch on schedule regardless of whether all the satellites are ready. https://spacenews.com/spacex-says-...


13

Don't take random youtube videos as fact. That part of that video was incorrect. The unmanned SpaceX Dragon has three pairs of computers used for flight control (so six flight control computers), and has 54 processors in all. The Falcon 9 launch vehicle has another 30+ processors. See http://aviationweek.com/blog/dragons-radiation-tolerant-design. Orbital's ...


13

SpaceX is proposing launch vehicle, as a first stage, and a second stage that would transit to Mars. Interplanetary Space Transport (ITS). The final size is not really confirmed, and they should actually build it before we compare it, but using chemical rockets, it is quite a bit larger than a Saturn V. The Saturn V used 5 F-1 engines with around 1.5 ...


13

Orbital Sciences likes solid rockets. They've produced the Taurus/Minotaur all-solid booster. And, in its three-stage configuration the Pegasus is all-solid. Ignoring that kerosene-fueled launch platform of course.


12

We can't even directly rebuild a Saturn V at this point (without tons of new R&D) because the tools and manufacturing processes no longer exist and we've lost the institutional knowledge of the people who built it that have since retired: Why not build Saturn V's again? Copying a design that we've never built is way more complex than trying to ...


12

It's important to keep in mind two very important concepts: Launch and orbit insertion are typically two distinct phases of flight. Ground controllers have very limited options during both phases. Once the launch starts, about the only thing the mission control team can do is make the vehicle blow up. Most of those fantastic explosions you see of launch ...


12

It's not hypergolics per se that are super-desirable for ICBMs, but room-temperature-storable fuels. ICBMs have to stay ready for long periods of time and be launched on short notice, so that means they have to stay fueled up more or less constantly. In practice, that means solid fuels or something in the UDMH/NTO family. A cryogenic fuel ICBM would need ...


12

In addition to SS-520-4, I would also point to Chinese CZ-11 rocket, Israeli Shavit and many others


11

Air launching has been around for awhile, see the Pegasus rocket system as an example. The White Knight is another system. The main goal of much rocket development is cost reduction, and air launching is a way to reduce the size and complexity of a rocket by using an airplane to get it part of the way. So far all the aircraft used for air launch have been ...


11

Atmospheric drag vs gravitational drag curve. The turn is not an instantaneous, or even a short maneuver - it begins either shortly after clearing the tower or in some cases - even before launch! and lasts until vertical speed is sufficient to clear the atmosphere and reach vicinity of apogeum, quite late into the flight. The trajectory - and directly ...


11

I can provide details only for the Space Shuttle. 1) Up to 155,000 feet - the approximate altitude of SRB separation - the end of first stage flight. Here are example wind plots (from here) [Note the error on the Y axis label - it should be meters, not km] a. Jet stream winds and associated wind shear b. Sinusoidal variation in wind with altitude c. ...


11

Despite the stated goal of shifting all US launches to the shuttle, all three major US uncrewed launcher families of the era remained in production. Each family reduced production and launch rates significantly during the early shuttle era (1981-1986), but I think there was a general sense even before the 1986 Challenger disaster that the shuttle wasn't ...


10

That's a hydrogen vent fin disposing of GH2 (gaseous hydrogen) that can outgas into the payload fairing from the Centaur upper stage's LH2 (liquid hydrogen) tank that is stored in a balloon tank at the top of the upper stage. From History of the Titan Centaur Launch Vehicle (PDF):     This liquid hydrogen leakage caused explosion of the ...


10

Interest was lost mostly because R&D money dried up, and also because the shuttle proved that reusability was difficult and expensive. SSTOs generally have worse payload fractions than staged launchers, with no inherent advantage in exchange. In the later portion of ascent, after burning most of its fuel, an SSTO is carrying significant mass in now-...


10

Are launch fairings pressurized to 1 atmosphere for the benefit of the cargo? No, pressure within the fairing will drop gradually during the launch. The reason for the pressurization system is to control the pressure change, to protect the cargo from sudden changes. The Falcon 9 User's Manual has a section on "Fairing Internal Pressure", which describes ...


10

Your assumption is incorrect, the answer is pretty straight forward: It has less payload to geo-stationary orbit than to a trans-lunar trajectory, because the latter takes less delta V. The burns for a Hohmann transfer to geostationary orbit from LEO are: 2.42km/s and 1.46km/s. A total of 3.88km/s. A trans lunar injection burn from LEO is 3.05km/s. This is ...


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