58

The Earth's orbital speed around the sun is about 30km/s. Firing a bullet from the vicinity of Earth's frame of motion (e.g. from low Earth orbit) to hit the sun would require cancelling out most of that velocity -- about 25 times the speed of a normal rifle bullet. This might be achievable with a specialized weapon with a very long barrel and a very small ...


42

T-Rex with his tiny brain overlooks the Coriolis force. If the astronaut pointed the gun at the Sun and shot a bullet, it would miss spectacularly. The orbital motion of the Earth makes for a sideward motion of about 30km/s. Depending on how you approach the problem of throwing stuff (radioactive waste and bullets are the same problem) in the Sun, you ...


37

You've hit on a really interesting question. To answer this, I'm going to look at JPL Horizons, using the center of the Earth and the center of the Moon as the distances provided. I'm going to look at each of the Apollo missions, with the time that they were orbiting the Moon, showing the max distance, with 10 minute increments included. All distances in kms,...


31

New Horizons went into Earth parking orbit first, so it doesn't count. For a suborbital direct ascent trajectory, some early lunar probes (USSR's Luna-1 for example) would hold this record. Otherwise, early vertical research probes included the Blue Scout Junior, one of which reached 44400 km on 1961 Dec 4 (mission O-2) - another may have reached 225000 km ...


29

This sort of spacecraft is known as a "cycler". You hit on the problem with it: you have to match its trajectory/velocity exactly in order to dock with it, so if you can reach the cycler, you could already reach the cycler's destination. There's no slowing down of the cycler for the same reason. In principle, if you connected to the cycler with a very ...


29

The diagram you show is the digital version of a drawing by someone with an Etch-a-Sketch: completely inaccurate. The diagram below is accurate, showing Pioneer 10 & 11 and Voyager 1 & 2 trajectories in a heliocentric, inertial reference frame, of course with the ecliptic N-S dimension collapsed. No retrograde, no dog-legs between planets. Every now ...


26

First order analysis Given that we have practical ion thrusters, it's time to look at them. Deep Space 1 The DS1 probe massed 387kg, had 83kg of fuel, operated for 162 days, and generated 92mN. So, it generated about 0.2mm/s^2. The craft is not tanks-dry, either. It has approximately 6 months (180 days) of fuel per design. That's a roughly 20% fuel ...


25

The journey to the destination is about always completely pre-planned. All the gravity assists, close fly-bys, and so on, are planned before launch - and often long before the probe design is completed, as often the requirements of the trajectory influence design considerations: ability to hibernate, delta-V of the engines, tolerance to heat if the probe is ...


25

It doesn't really work that way. We can use the Sun to change direction, but we need rocket thrust to increase speed with the msneuver. To begin with, the closest stars (apart from the Sun) are not close. If we were somehow to reach escape velocity from the Solar System (which this method won't do, see below), we would still be moving at only a small ...


23

I found it. It was NOSS 3-1, a satellite pair. Found it through heavens above. The pair also explains the apparent tumbling. However, it seemed much brighter than 4.1, but it‘s definitely it.


23

The "gravitational" (slingshot) maneuvers space probes are performing are actually not so much about gravity. The gravity is method to "tie" temporarily these two bodies, but you could (purely hypothetically of course) use something else, some superstrong tether or so ... "Slingshot maneuver" is in fact much better name in this regard. What actually happens ...


22

To answer the question literally: you'd be looking for NASA Apollo Trajectory (NAT) data files. The report Apollo Mission 11, Trajectory Reconstruction and Postflight Analysis Volume 1 (PDF) provides a summary for Apollo 11 and mentions that the raw NAT data is available in Volume 2 of the report. I have yet to find Volume 2 though, perhaps because The ...


22

I believe the answer is yes, but just barely. The distance from the Earth to the moon varies significantly over time, from 356,400 to 406,700 km. I plugged the dates of orbital entry and departure for each of the lunar Apollo missions (8, 10-17) into pyephem to find the ranges of lunar distance. At Apollo 13's flyby, the moon was one day past apogee and ...


21

The STEREO satellites used multiple gravitational assists from the Moon to significantly decrease the amount of fuel needed to put those two satellites into heliocentric orbits. The first flyby resulted in STEREO ahead (STEREO-A) being ejected from the Earth-Moon system with a semi-major axis slightly less than that of the Earth-Moon system. STEREO-A has a ...


21

SpaceX published numbers on their website near the bottom of the page. I snapped an image to show here, since their formatting is prettier than I can do in Markdown. You can see that it can do pretty much any of the missions. Now you could probably do a better job with a third stage/kick stage, because while the second stage Merlin-1D Vac has a lot of ...


21

Movies are misleading. Space is enormous, and almost entirely empty. Even our ”asteroid belt” is mostly empty space; we have flown several missions straight through the belt to the planets beyond without hitting anything. Low Earth orbit has collected quite a bit of space junk over the years, but even so, interplanetary probes spend only a very short time ...


20

When a spacecraft is launched from Earth, it's moving counterclockwise across your diagram at a speed of 30 km/s (the same speed as Earth itself), plus a speed of 10-15 km/s in the direction of the launch. The trajectory you propose is only possible if you reduce the spacecraft's counterclockwise speed to zero. The fastest launch ever (New Horizons) reached ...


20

It's a bit of a misconception that the shuttle used S-turns to slow down. To quote the Entry, TAEM, and Approach/Landing Guidance Workbook by the United Space Alliance: The next time you hear someone talk about the shuttle doing roll reversals to bleed off energy, do not listen. The shuttle does roll reversals because it has a very small alpha envelope. ...


20

In many cases, propellant is only dumped when the spacecraft’s mission is complete, so any minor changes to trajectory caused by the dump are unimportant. If you must avoid any trajectory or attitude change due to a propellant dump, the most straightforward way is to have multiple vents pointing in opposite directions, so the propulsive forces cancel out.


20

Your intuition is quite correct. The Hohmann transfer orbit is a bi-tangential orbit, so at the point where the spacecraft leaves Earth, it is travelling in parallel to us. In the case of Mars, we want to travel slightly faster than the Earth in order to lift our aphelion up to the orbit of Mars, meaning we want a little extra velocity on top of the prograde ...


19

According to the plan, an Apollo mission to the moon uses eleven-ish burns. Here are the expected maneuvers: Launch from earth. This you might count as three burns, since it requires all three stages of the Saturn V rocket. They're not only launching from earth at this point, but they're also burning to get into a circular orbit around the earth. Leave ...


19

Altitude drops like that are common when the orbital stage has a high-efficiency, low-thrust engine. It takes a few minutes for the upper stage to bring the craft up to orbital speed. During that period, the craft is indeed starting to fall back towards Earth. The rocket's travel over the curvature of the Earth contributes an effective altitude gain that ...


19

So first of all, every space probe changes direction constantly due to the gravitational attraction of the Sun, and the planets and moons. For instance the Parker Solar probe orbits the Sun every few months, changing its motion (as seen, for example by an observer stationary with respect to the Sun and above its North pole) through a full 360 degrees each ...


18

Considering that Voyager 1 is already 126 AU from the Sun 36 years since launch, there should be no reason that it would not be possible energetically using a normal launch, small maneuvers, and planetary flybys. Just a Jupiter flyby should be sufficient. Jupiter will also provide the necessary change in inclination. Designing a probe that is assured to ...


18

It is absolutely possible, just not advised. New Horizons was launched at Solar System Escape Velocity, meaning it could have visited anywhere beyond Earth without stopping. It did visit Jupiter, however, that was to allow it to leave even faster, the Jupiter stop was purely optional. As for the issue of human capable spacecraft, again, it could be done, if ...


18

The asteroid belt isn't nearly as dense as popular media makes it out to be. An answer from the Dawn Mission's FAQ, specifically "What is the average distance between individual asteroids? (6/13/10)", helps here. Asteroids are not distributed uniformly in the asteroid belt, but could be approximated to be evenly spaced in a region from 2.2 AU (1 AU ...


17

There are two major reasons you may be going outside the ecliptical plane: You want to get to a particular star. You want to put the Sun on a direct line between your craft and another point in the sky (usually a star system or an interstellar probe to that star system) to exploit Sun's gravitational lens (that is, your destination starts around 550-740 AU ...


16

From the Yellow Book: "06/2022 - Launch by Ariane-5 ECA + EVEE-type Cruise" EVEE means Earth Venus Earth Earth - a long series of gravity assist maneuvers to fit more payload into the Ariane 5 ECA launcher capabilities. Why an Earth slingshot comes first: The fact that the first arc includes an Earth gravity assist for both launch opportunities ...


16

Not sure if this counts, but New Horizons was launched directly into an escape trajectory and did not enter orbit. It made it to Pluto and beyond. From Wikipedia: New Horizons was launched from Cape Canaveral Air Force Station directly into an Earth-and-solar escape trajectory with a speed of about 16.26 kilometers per second That might be considered ...


15

The asteroid belt is roughly 6 Astronomical Units wide, and so when it is drawn only 600 pixels wide with each asteroid a handful of pixels wide, you end up with each asteroid being five times bigger than the Sun! I've borrowed a small piece of the image used in @jos' excellent answer to show what I mean. As pointed out in this answer, Wikipedia says: ...


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