# Tag Info

90

You see that tiny thing on the far left? That's the Falcon 1. It's a comparable size to Blue Origin's New Shepard spacecraft and SpaceX's Grasshopper (which accomplished a similar feat 6 times, around 3 years ago, but didn't *technically* enter space). You see those 3 in the middle? That's what SpaceX landed today. Grasshopper / Blue Origin were ...

47

Here is an image of the two trajectories. (From Reddit) Here is a nice infographic explaining the differences between the two. Kudos for both images above to Jon Ross of ZLSA Design. And here is another fun size comparison (source unknown): This video especially where I cued that link, should also show an aspect of the discussion.

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Blue Origin's flight was straight-up, straight-down, with a fairly small rocket that can't carry much useful payload. It's a great demonstration of technology, but it's only practical for space tourism. Today's Falcon flight was a paid orbital payload mission. In order to get the payload to orbit, the first stage has to not only bring the second stage to ...

27

Blue Origins Flew to just over 100 km (100.5), just enough to say it went to space. Landed at the same site, presumably went straight up and down. Carried a suborbital payload. Announced only after the fact. SpaceX Separation from 1st stage at 79.3 km, 5929 km/hr (From webcast video) At that point, the upward speed was about (86.6-75.3)/7 or 1.6 km/ ...

18

Reusability is the big factor. Kerosene engines have issues with "coking", where solid carbon is deposited throughout the engine's pipes. (See this dissertation and its supporting research for more details.) This isn't a major issue with expendable engines, but it drives up costs when trying to reuse the engines. The BO New Glenn's first stage is planned to ...

17

A moving ship can use stabilizers to reduce roll. Stabilizers are underwater wings that need to move relative to the water for them to work. Ship stabilizers are fins or rotors mounted beneath the waterline and emerging laterally from the hull to reduce a ship's roll due to wind or waves. Active fins are controlled by a gyroscopic control system. When ...

14

In 2015-2016, the New Glenn design was expected to use a single BE-4 methane-LOX engine on the second stage (about 2400kN thrust), and a single BE-3 (the same as the suborbital New Shepard's single engine, and likely in the 500-600kN range for the upper stage version) on an optional third stage. There wasn't any need for an engine in between the power of the ...

12

It would be extremely unstable. There are 2 things that weight a lot on an empty rocket, the capsule and the engine. With the two of them on opposite sides, the rocket would become extremely unstable. Separating the two allows for the entire system to be more stable. This is particularly important when it is on the ground, where it could easily tip over if ...

11

The startup of the BE-3 is slower because it uses the Tap-Off cycle. Hot gas from the main combustion chamber is tapped off to run the twin turbines that power the fuel (LH2) and oxidizer (LOX) turbopumps. In the BE-3 engine diagram you can see that each of the turbopumps has its own turbine and exhaust. Startup sequence: Fuel and Oxidizer at tank ...

10

The capsule is equipped with a Launch Escape System capable of aborting from pad or in-flight. The pad abort was already tested in 2012: http://www.nasa.gov/exploration/commercial/crew/blue-origin-padescapetest.html And the in flight escape was tested in October 2016:

10

I don't care to enter the fray of what is a subsidy, etc. but Parabolic Arc recently published a nice summary of what has been spent (or contracted for) by NASA on the commercial contracts to date. (Note: this is incomplete, it includes NASA spending on commercial crew and cargo only. DOD contracts with Blue Origin, for example, are not listed.) From this, ...

9

As pointed out by @Thomas, this nice thesis Radiation from High Pressure Hydrogen-Oxygen Flames and its Use in Assessing Rocket Combustion Instability - Ph. D. Thesis, Fiala, T., 2015 discusses this phenomenon. The term $\color{blue}{\text{blue radiation}}$ is suggested as the best available. While there are several narrow spectral lines int the near UV (...

9

Blue Origin (BO) chosed LH2 for BE-3 rocket engine because of the performance. "Performance drove the decision to use hydrogen fuel in the BE-3," said Rob Meyerson in an interview in 2013, president and program manager in BO. Looking in to perspective, BO had ambitions for space exploration and they would not stop the development only with a suborbital ...

7

Let's look at Wikipedia for possible liquid rocket fuels. The key item is the Exhaust Velocity. Let's remove any that could be toxic, so no Beryllium, Florine, or Boron, despite the fact that each could make a very efficient rocket. $H_2{\space}LOX$- 3816 $CH_4{\space}LOX$- 3034 $C_2H_6{\space}LOX$- 3006 $C_2H_4{\space}LOX$- 3053 $\textrm{RP1}{\space}LOX$- ...

7

Several of the answer have stressed the difference in size of the vehicles, and that the trajectories are very different. While those are all good points, I think the fundamental thing which makes SpaceX's feat a good deal more impressive though is that it was done with a lower stage which was being used as part of a regular mission, and not by a vehicle ...

7

I may have my own answer. It looks like this test vehicle uses a single BE-3 engine, which only has about 110,000 lbs of thrust. We have seen the SpaceX Grasshopper and F9R Dev1 vehicles take off from flat surfaces on a single engine as well, and the Merlin 1D engine produces 145,000 lbs of thrust (in 85% performance mode that apparently it has been ...

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There's 2 major reasons: safety and practicality Safety: If you look at the history of booster landings it is not a proven technology, the reliability is not good enough for safety. Don't get me wrong, it's amazing that they can land a booster for re-use, and it works a good portion of the time, however when it goes wrong it goes very, very wrong very fast. ...

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LOX and LH2 tanks that are boiling from equilibrium can be replenished via umbilicals. You can see one here: In some launch videos, it can be seen to detach right around engine start time. This lets any boil-off be replenished right up to launch. Note this is different from the Falcon 9, where the issue isn’t boil-off but rather warming of the deeply-...

5

They are planning to take off and land vertically, so the vehicle has to be designed to tolerate engines firing close to the ground without a trench anyway. The amount of thrust that an engine provides doesn't determine the need for a trench by itself. You could, for example, raise the entire vehicle or provide protection on the engine itself instead of ...

5

Quoting an average success rate for rocket launches as a whole is not very useful. Atlas V has a near-perfect record, for instance, while Zenit and Proton have about 88% rates. Presently, Falcon 9's partial success rate is 95% and its full success rate is 88% as an expendable, but it's still quite a young launcher. We won't know how it performs as a ...

5

The mass of a pendulum doesn't affect its period, but the length does; the longer your rocket, the slower it will tip (in degrees-per-second) while off-balance, and the more time you have to compensate for minor shifts before you have a catastrophe. Gimbaled rockets have excellent control authority, and the engine thrust will scale with the rocket mass, so ...

5

Based on other promotional images of New Glenn that show it from different angles, they would appear to be fins: (Note how the edge appears to be sharp, suggesting a thin shape) Image source: https://www.blueorigin.com/assets/photos/new-glenn/blueorigin_newglenn_ascent_web.jpg

4

According to the Blue Origin publicity web site https://www.blueorigin.com/new-shepard/ , the aft fin hydraulics are effective up to mach 4 (altitude isn't specified, but actual max is [remember it's sub-orbital] mach 3), and those fins are also used as steering canards during descent. If you are interested in re-entry control, then you should also check ...

4

One advantage is mass savings if you don't need to coat the surface with something else (or if that "something else" is lighter than the matte white paint would be). The most obvious example where we do have some numbers is the Space Shuttle External Tank: The first two, used for STS-1 and STS-2, were painted white to protect the tanks from ultraviolet ...

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We don't know yet. The closest we have come is Beth Moses who flew as a "test passenger" in VSS Unity VF-01 and became the first non-pilot and the first woman to be awarded the FAA Commercial Astronaut Wings. However, the FAA only awards Commercial Astronaut Wings to flight crew who promote the safety of commercial space launch vehicles, and ...

4

Blue Origin's manufacturing facility in Florida is already built and built horizontally for New Glenn: Also, their launch pad SLC-36 has what looks like a horizontal hangar (similar to what Space-X has at LC-39A): Where the blue rectangle is the approximate horizontal footprint of the New Glenn full stack (~95m x 7 m), imagery from Feb. 2020. As they do ...

3

It's worth noting this is rather unique as its requried to be aerodynamically stable when going forwards and backwards. This is tricky as the centre-of-lift/pressure has to be 'behind' the centre of mass in both directions. The anular-fin being covered when the capsule is on, and open after release (which correlates to going 'up' and 'down'), helps with ...

3

The Falcon 9's grid fins exist to solve a particular problem: Control during engines-first descent. Aerodynamic stability during that phase comes from having the center of mass well below/ahead of the center of pressure due to heavy engines at the bottom. But a stable descent to the wrong place isn't the desired outcome. Further, Falcon 9 flies a specific ...

3

Fins are usually used for aerodynamically controlling the vehicle. Grid fins are a simpler and more storable form (as mentioned folding flat, especially during ascent) of fins as compared to the conventional ones. The New Glenn seems to follow on the legacy of fins developed, tested, and validated during the New Shepard flights, that have used conventional ...

3

It appears that Blue Origin's New Glenn 3-stage rocket will be using a variant of the hydrogen-fueled BE-3 for its upper stage engine, which makes a great deal of sense -- enough that we can assume it was the plan from the beginning. Hydrogen is a better choice for upper stage than for boosters, and generally harder to engineer than a methane engine. Having ...

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