# Tag Info

16

Yes, it would explode. Most hand grenades are nowadays triggered chemically, electrically or contain a fuze enclosed within the assembly, so they don't require atmospheric oxygen to ignite, are watertight and otherwise more reliably go off at a preset time since activation. You would however create a large number of dangerous debris that would float forever,...

15

Here is the Apollo 11 (Columbia and Eagle) graph of center of gravity during the AS-506 flight, taken from the APOLLO/SATURN V POSTFLIGHT TRAJECTORY - AS-506 (rather large scanned PDF):        I selected Apollo 11 flight for historical significance, but you could find many other postflight telemetry and flight analysis ...

10

The altitudes are not what I would call ridiculous. Though you seem prone to using unjustified superlatives in your questions. The optimum, i.e. minimum injection velocity sub-orbit was provided by HopDavid in this answer. With some manipulation, you get that the maximum altitude of the optimal trajectory is: {r\over 2}\left(\sin{\alpha\over 2}+\cos{\...

9

I'm going to hazard and say it's not very likely, more to human reaction time than anything. If one has to assume that the computers are not available for the quick launch sequence, one also has to accept that they are not available to control timing. Here's a blurb about the thruster capacity in the various nodes, from Spaceflight 101. SKD, the Soyuz ...

7

I don't know how commonly rocket CGs are published. You can estimate it reasonably well from published weights and dimensions by modeling engines, fuel tank, and oxidizer tank as cylinders of uniform density, and computing weighted averages of the centers of those cylinders. If you don't know what order the fuel and oxidizer tanks are stacked in, assume ...

7

A connection between two different periodic orbits around Lagrange / libration points is often termed a heteroclinic connection. Although the L1 and L2 points in the Earth-Moon system are themselves unstable equilibrium points, there are stable periodic (or quasi-periodic) orbits that can be found around each point. From these orbits, it is possible to ...

7

There can be many reasons: Test of technology Doing in-situ measurements in the mesosphere, which is too high for balloons, too low for satellites Performing microgravity experiments where parabolic flights have too short segments of microgravity but where launching a spacecraft is too expensive This list is almost certainly incomplete.

5

There was an earlier question about suborbital hops. I will reuse some of the diagrams and explanation from that answer. A minimum energy ellipse between departure and destination corners of a Lambert space triangle is described on page 65 of the 1993 edition of Prussing and Conway's Orbital Mechanics textbook. In this particular Lambert Space triangle, ...

5

Short answer: none that are binding. Longer answer: Most space-faring countries and organizations voluntarily implement standards that abide by the principles in the space debris mitigation guidelines of the Scientific and Technical Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space. In the case of NASA, this is implemented by ...

5

From Elon Musk AMA on r/space Will be starting with a full-scale Ship doing short hops of a few hundred kilometers altitude and lateral distance. Those are fairly easy on the vehicle, as no heat shield is needed, we can have a large amount of reserve propellant and don't need the high area ratio, deep space Raptor engines. Next step will be ...

4

From Gerald R. Hintz, Orbital Mechanics and Astrodynamics: Techniques and Tools for Space Missions, 2015: Michielsen devised a graphical display for all lunar transfer information, including passage effects, on a single plot. This chart is presented in Fig. 7.9 [missing from preview, see below] with an application to the Apollo 11 Mission. The $v_r$ ...

4

In the video Arianespace TV VS 21 Live Launch English after the spacecraft has entered "cruise" in LEO, the announcer says: Once the frigate is sent an “Engine off” we enter what we call the ballistic phase, and ballistic is probably a word I’m guessing that you’ve heard quite a lot over the years, and I believe, correct me if I’m wrong, that it means ...

4

There is one difference with typical orbital calculations: the Moon's gravity field is uneven, due to mass concentrations in various places. If your trajectory crosses one of these mass concentrations, your trajectory will be changed a bit. The gravity value differs by about 0.3% across the Moon's surface.

3

For deep space missions, there usually is a conjugation analysis, but not for the reasons you predicted. In fact, they do it to see if there's any secondary objects that can be studied while on the way to their destination. The majority of asteroids that have been photographed up close, in fact, were such accidents. From the Wikipedia Article, here's a few ...

3

The document you cited is fundamentally flawed. It has the z axes in the ECI and GEOC frames co-aligned. That's just wrong. It ignores precession and nutation. The full theory is amazingly complex. You probably don't need that. (You would have graduate advisors who would have already pointed you to the necessary software if you did need the full theory.) ...

3

Let's see if this is even possible. There are 3 engines on the upper stage of the BFR that are rated for atmospheric. Each engine, at ground level, has about 3 MN of thrust. The fully loaded weight is about 1335 tons. Gravity is pulling on that mass at a force of about 12 MN. Bottom line, the second stage can't lift off of the ground fully fueled. It could ...

3

You'd better install some RCS on your projectiles. The problem is you need quite a bit of energy, accelerating your projectiles to something of order of 20-50km/s depending on alignment. And if your calculation program tells you you need to launch at 25746.32m/s it better not be 25746.28m/s or you'll miss. And keep the angle accurate to about a second (1/...

2

If you look at a pure definition from Webster's the answer is ambiguous with respect to in-orbit flight: of or relating to the science of the motion of projectiles in flight In most contexts I've seen, ballistic usually implies intersecting the central body. However orbiting satellites in low orbit (where atmospheric effects are noticeable) have a ...

2

Here is a generic trajectory. Source (see for more details)

2

It depends on how long the grenade has been exposed to space. You might find the vacuum got to the mechanism if it's been out there long enough. Assuming the trigger doesn't fail due to vacuum welding it's going to go boom.

1

In its simplest form it isn't different from any other type of orbital calculation. The only difference you may notice is that the perigee of the orbit may be within the surface of the moon. For a quick thought experiment, imagine drawing an ellipse onto a 2D picture of the moon. If you make this ellipse pretty small (and pretty circular) you can connect ...

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