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37

TL;DR: The low technology readiness, the very, very low thrust, and the need for a catalyst bed means this was and still is the wrong technology for the intended purpose of a launch abort system and maneuvering in low Earth orbit. Low technology readiness SpaceX began working on Dragon V2 over five years ago. At that point, AF-M315E had a rather low ...


22

As @OrganicMarble alluded to, the Buran Soviet shuttle was designed with turbojet engines (see here; and here, under "The engines") to extend the range of possible landing locations given the re-entry circumstances. Test versions had those engines (the same engines used in the Su-27 fighter) installed, but those were never launched into space. The version ...


21

Heat doesn't. The intense heat does, however, strip off electrons from molecules in the upper atmosphere, leaving an electrically charged plasma. This plasma interferes with radio communications to such an extent there is a complete radio blackout until the capsule has decelerated to such an extent plasma is no longer formed - this can take 30 seconds or ...


18

I don't believe any vehicles equipped with air-breathing engines have flown to space and returned. Some test vehicles for Buran had jet engines installed, but they did not fly to space. In this picture of a Buran test vehicle, you can see that the jet engine mounts interfere with the reaction control jet nozzles, showing that this configuration could not be ...


16

Capsules like Apollo and Orion are mainly open space internally (the crew cabin); they have no problem floating by themselves (like a metal-hulled boat would). The conical capsule shape by itself will float in either of two orientations: stable 1 (base down, nose up) and stable 2 (nose down). In stable 2, the crew is hanging upside down in their seats and ...


12

Dragon Capsules: 5 Return Visitors as of 12/2018 The SpaceX subreddit has a nice table with information on the individual Dragon spacecraft. Several of the Dragon capsules have flown multiple ISS missions. The Dragon 1 spacecraft IDs are of the form C1xx, sometimes presented with a '.2' suffix on second flight (i.e. C106 is reflown as C106.2). The Dragon ...


11

Despite a higher risk of a fire, pure oxygen also has some advantages. First, the internal pressure of the vessel is only a fifth of a normal breathing mix, allowing less structural load on the hull of the spacecraft. The resupply system is also simplified, because a system including nitrogen must have an extra tank for the nitrogen. (If you had them mixed, ...


10

The Soyuz capsule can land in water, even if that is by no means an optimal scenario. The last splashdown of a crewed spacecraft was Soyuz 23 landing in a lake in Kazakhstan. The recovery took a while as locating the spacecraft at night after the communication equipment failed was difficult. Splashdown tests have later been performed, and a water landing ...


9

According to Apollo Experience Report: Spacecraft Structure Subsystem, NASA Tech Note D-7780, pp. 15-16, that capsule was either Command Module boilerplate BP-1 or BP-2, in a "landing impact test" sometime between 1962 and 1964. The Block I landing impact test program consisted of numerous impacts of boilerplate test vehicles on both land and water. ...


8

Though it hasn't been flown yet, British company Reaction Engines has designed a Single-Stage to Orbit reusable spaceplane with rocket engines that utilize atmospheric oxygen for a substantial portion of the ascent, before switching to internal LOX tanks once above ~85,000 ft. They have already designed and performed some limited tests on the engine ...


8

According to spaceflight101: [The Soyuz capsule] is outfitted with the spacecraft's fully redundant parachute system [...] I would assume that the designers needed to keep a certain precision for the landing. If they deployed the main parachute and the backup simultaneously, the decent speed may be lowered to the point that they could no longer satisfy ...


7

I'll look at the physical side why zu they are not used: Air breathing engines (or rather an engine) consist of two parts: Fuel (usually not the same as the rocket engines - RP-1 is out) the Engines themselves And here the tyrany of space flight kicks in: any mass you want to bring down, you first need to bring up. Which increases the dry weight in the ...


6

Yes, they can, at least they are designed to do such. Here's some links supporting that: http://www.space.com/21541-nasa-orion-spacecraft-reusable.html http://en.wikipedia.org/wiki/Orion_%28spacecraft%29#Crew_module_.28CM.29 " The CM is designed to be refurbished and reused." http://www.informationweek.com/government/leadership/nasa-orion-space-capsule-has-...


6

One environment the capsules definitely can't land on is steep mountain slopes. If the capsule starts rolling down the slope, there's very little the astronauts can do. This will include glaciers, buildings, generally once the capsule makes the touchdown, it better not continue falling. Forests with tall trees (like Amazon jungle) may prove lethal, as the ...


5

Not so obvious, but Leonardo module could be on the list. It made like 8 visits to the ISS within different Shuttle missions as MPLM, and then was left there permanently attached as PMM. And so could Raffaello with his four flights as MPLM-2. Although it has ended up its days on the ground.


5

It was one of many Apollo boilerplate drop tests. See this page for many more drop test images. Some images of boilerplates 1, 2.


5

Problem 1: "Slow down on reentry"... dealing with many times the speed of sound. Turbojet and Turbo fan do not work well at many times the speed of sound, they normally slow down air to slower than speed of sound at combustion stage, so subsonic combustion can keep up with the air. (You are also dealing with vast amounts of energy that would likely ...


4

According to this article, the Apollo 11 CM was moved to Udvar-Hazy at the end of 2016. As none of the other Apollo CMs seem to be there according to this page, I would guess that is in fact Columbia.


4

Yes. How do I know that? Well, multiple sources say that a layer of 'electrically charged plasma' develops around the ship. Since the plasma is electrically charged (highly charged), some of that charge will be transferred to the hull of the vehicle. I couldn't find any info on the amount of charge generated, but I'm sure it's quite high considering the ...


3

Clearly there is a window. Upper left, watch lighting change within the capsule and on astronaut's face after fairing separation. above: GIF made from screen captures from the following YouTube video:


3

It is very difficult to make a soft or hybrid space suit manouverable with higher pressure (over 5 or 6 psi for example), because they are effectively just big balloons which just get stiffer and stiffer with more pressure. With such a low pressures, using pure oxygen is mandatory to get a human breathable partial pressure for oxygen. For this reason, all ...


3

The success of SpaceX is based mostly on using the best of well-proofed technologies not on bold innovations. There are innovations in production process and in business model but very few in rocket design. High energetic monoprppellants are very dangerous. Hydroxylammonium nitrate (AF-M315E) is rated as an Explosive. It is probably unacceptable for human ...


2

This is a very hard question to answer, I'll start with that. First, you need to determine if you're talking about the cost of development as well as the cost of each capsule. If we count the development cost then it's pretty easy to do this calculation for the Apollo spacecraft: The total cost of the CSM for development and the units produced was $...


2

In this closeup, it's pretty obvious this is an air hose. They are routinely used to control the temperature inside the fairing. Here's a similar system on a Vega rocket (for the LISA Pathfinder launch): LISA Pathfinder, ready for launch. In this image, taken with an ultra-wide angle fisheye lens on November 19, the spacecraft is hidden from view, ...


2

@Uwe's answer is great, and presumably to the question Is there a practical maximum size for a space capsule returning to Earth? the answer there is pretty much "yes" based on current capsule technology. Space planes and "rockets with flippers" can be larger perhaps, but @Uwe's square-cube argument would still apply. I'll address the last bit: Would ...


2

Let us consider the square cube ratio. If we enlarge an Apollo CM capsule by a linear factor of 2, its surface scales with factor 4 (the square of 2) and its mass and volume scales with the factor 8 (the cube of 2). But for the hot phase of reentry we need the same path length in the upper atmosphere. So the deceleration (g force) should be the same as for ...


2

Here is the descent profile for Soyuz. At 08:53:30 the speed is 7.62km/s and touchdown is at 09:14:39. Over 1269 seconds the object sheds 7.62 km/s. Kinetic energy is $.5mv^2$. So that's 29,032,200 joules per kilogram. 29,032,200 joules/1269 seconds = 22878 watts. Over that 21 minute interval I get about 23 kilowatts per kilogram. According to the ...


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