46
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Why has a rocket system like Starship never been proposed before? It does not seem to use any new science, materials or fuels
I wonder why nobody ever proposed a space launch system like Starship.
What exactly do you mean by "like Starship"? Systems like Starship have been proposed before, although differing in ...
- 167k
45
votes
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Why can solid rockets be both the skinniest and most spherical launch vehicles while liquid fuel rockets have a more limited range of aspect ratios?
The squat end of the spectrum has little to do with solids versus liquids and everything to do with aerodynamics. Spherical tankage is most weight-efficient, so you'd expect squat stages in cases ...
- 167k
42
votes
Why has a rocket system like Starship never been proposed before? It does not seem to use any new science, materials or fuels
Fundamentally, it's because of economics. There simply wasn't any demand for a large rocket between today and the space race.
Let's analyze what (I think) makes the Starship concept special:
Size: ...
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36
votes
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Why doesn't the USA use structurally stronger rockets for the more important launches?
I think you got it wrong: R-7 launches sometimes are also postponed due to weather. Just to name few examples: 18 December 2018, 9 March 2018, 22 April 2016 - Kouru; March 22, 2016 - Baikonur, 2 ...
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33
votes
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How is thrust transmitted from strap on boosters to the central core?
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 ...
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33
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Why was the engine of the launch vehicle recently tested in Iran "not a very good missile engine"?
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"?
The old Soviet engine on the Scud-B uses a ...
- 167k
29
votes
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Why do we need dedicated launch vehicles for small satellites?
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 ...
- 126k
28
votes
Why doesn't the USA use structurally stronger rockets for the more important launches?
This question is based on several serious misconceptions.
R-7 launches never get postponed due to weather.
Actually, they do. "The launch of the Soyuz 2-1A modernized carrier rocket, scheduled for ...
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22
votes
How is thrust transmitted from strap on boosters to the central core?
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 ...
- 167k
21
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Do launchers using only solid propellant exist?
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 ...
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21
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Why are the blueprints of old satellites still not available to public?
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. ...
- 126k
20
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Why was the engine of the launch vehicle recently tested in Iran "not a very good missile engine"?
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
- 178k
20
votes
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Launch system to get a 75,000 kg object to geostationary orbit?
Is there any current launch system that could get a 75,000 kg object to geostationary orbit?
No. (Starship/Super Heavy can, of course, do anything, but it's not a current launch system.)
If ...
- 167k
20
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Does a fully loaded Starship really have a thrust to weight ratio less than 1 at sea level?
Yes. It's not unusual for a second stage to have a TWR less than 1:1 at ignition; when it stages, it will have plenty of upward velocity imparted by the first stage, and as fuel is consumed the TWR ...
- 167k
19
votes
What does it mean for a launcher to be 'nuclear-certified'?
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, ...
- 121k
19
votes
What exactly is the purpose of connection links strapped between the rocket and the launch pad
In general, umbilicals are provided from the launch pad to the vehicle for any services that need to be provided after the vehicle is installed on the launch mount, and to remove hazardous gases from ...
- 178k
17
votes
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How can a rocket go straight up after ignition?
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).
...
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17
votes
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Why is SpaceX not creating its own launch vehicle for small satellites?
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 ...
- 58.5k
17
votes
Why do we need dedicated launch vehicles for small satellites?
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 ...
- 1,341
16
votes
Using large orbital launchers as sounding rockets. What are the opportunities and challenges?
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 ...
- 167k
15
votes
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What is/was the smallest orbital launch system, by total mass?
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.
...
- 126k
15
votes
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What are "high altitude winds" and why do they often delay rocket launches?
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 ...
- 178k
15
votes
Are submarine launches horizontal?
A ICBM rocket launched from a submarine should leave the water as fast as possible. Therefore the rocket has to leave the water vertically.
The rocket is blown out of the submarine by using compressed ...
- 48.8k
14
votes
Pressure inside a launch fairing - falcon 9
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 ...
- 178k
14
votes
Do launchers using only solid propellant exist?
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 ...
- 178k
14
votes
Rockoon on steroids
Before I start my answer:
This is not a rockoon anymore, since there is no balloon part. It's just a quirky air launched rocket.
My answer:
No.
What you are doing is:
Phase 1: Climb with a plane
...
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13
votes
How large could launchers become?
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 ...
- 79.3k
13
votes
Do launchers using only solid propellant exist?
In addition to SS-520-4, I would also point to Chinese CZ-11 rocket, Israeli Shavit and many others
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13
votes
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Was there any period of time when other U.S. launchers were abandoned in favor of the Shuttle?
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 ...
- 167k
13
votes
In what ways is helium used on modern launch vehicles?
Helium is used as a pressurant and purge gas. While no longer a "modern" launch system, the Space Shuttle made extensive use of helium to pressurize various systems and can perhaps serve as ...
- 178k
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