I need to fire an object into the sun...

I have an object approximately 30.7 x 44.5 x 10 cm, weighing about 5 kg. An unfortunately, I need to dispose of it. By dropping into the sun. (The instructions were very clear on this point)

Also unfortunately, I understand that, due to the laws of orbital mechanics, this would actually require more energy than launching an object out of the solar system.

Fortunately, I have a decent amount of funding, connections, and about 16 years to accomplish this. Is there any relatively off-the-shelf launch system available that can deliver the payload in the time available?

(Failing that…would anyone be in consulting on retrofitting the Pyramid of the Sun for power, drainage, and high-pressure meat slurry pipelines?)

Does it have the standard Evil Artifact attribute of indestructibility? I assume it does, or you’d just burn it.

In that case, it seems to me that one possibility would be to launch it along with a nuclear warhead into space, and then use the nuclear detonation (at a carefully calculated distance) to provide enough acceleration to put it on course for the Sun. I’m not a physicist though.

Wow, laughed so hard at this post. :slight_smile:

Thanks! You sir, just made my day.

I don’t quite understand this. Obviously if you want something to drop straight into the sun, you’ll need enough energy to cancel out the existing orbital momentum, which is enormous. But surely you can with much, much less energy expended alter the object’s orbit to be highly elliptical - to the point where the perihelion is inside the sun. Seems like you should be able to do a close approach to the moon or such using its gravity to alter the direction of your object’s orbital momentum to achieve such an orbit.

Would your long-term goals be reached if, instead of the sun, you launched it into, say, Jupiter? That’s much easier to do.

There’s no proven technology that can do this. The Solar Probe Plus will only get to 8.5 solar radii of the sun.

Of the several possible unproven technologies, Solar sail is probably your best bet, because the closer it gets to the sun, the more thrust it gets. I think 16 years is plenty of time - say, select several groups who are already doing research in solar sails, fund them and give them 4 years to launch prototypes, choose the best design and then build the “real” probe.

Is it important it makes it all the way to the sun? Because it would appear by the nature of the medium that all you would need to do is get it within a relative proximity to make that particular binding essentially unreadable.

No, there is no launch system that will be able to directly remove the 29.8 km/s orbital velocity at Earth orbit. You could bleed off a significant portion of that speed by performing swing-by maneuvers with other planets to bend your trajectory into the Sun, but ultiimately you are going to require a post-launch propulsive stage that gives impulse transfer that reduces the payload solar orbital energy by over -2 GJ. You can do less by getting using planetary swing-by maneuvers; while it might seem beneficial to head in-system, from a miinimum energy standpoint you are probably ultimately better served by heatding outware and doing your swing-bys one one or more of the outer planets like Jupiter or Saturn, and then bend your trajectory down into the Sun.


Why don’t you just launch it in the daytime?

What kind of mess has Spindoctor gotten herself into now?

'Bout the same, really. The “ideal” case, negating all orbital velocity so that the projectile “falls” directly into the sun, is, in fact, an example of such a highly eccentric orbit. You’re right, you could save a little energy by aiming within 1 solar radius of the center of the sun, rather than directly at the center of the sun…but not a whole lot.

Dramatic changes in an orbit’s eccentricity require dramatic changes in orbital velocity.

ETA: You can use the “slingshot effect” and, by flying close to Venus and Mercury, kill off some velocity that way, just as the Voyager probes picked up velocity by slingshotting past Jupiter.

Good god, man, just drop it on Venus, it would be utterly destroyed there.

(Hopefully before it thus drains all the love out of the universe)

Not really. The problem with that is twofold; one, by heading down your probe will increase in velocity and kinetic energy, and therefore the effect of a swing-by maneuver on changing momentum is less even if all other things are equal. If you head down to Venus or Mercury a swing-by manuever is just going to result in a highly elliptical orbit that may come close to the Sun, but will be moviing extremely fast that that point, and the slower you get your probe going, the more difficult it will be to make swing-by intercepts with Venus and Mercury; at some point, you will fall under the orbit of Mercury and still be moving too fast to fall into the Sun.

And of course, they aren’t equal; Jupiter (and to a lesser degree, Saturn) have much deeper gravity wells, and therefore can effect a much more significant change in momentum. This, combined with the lower kinetic energy of the probe at the point of intercept allows for a much lower delta-V requirement. If you head out toward Jupiter, you should fairly easily be able to plot a swing-by that gives you a long, slow quasi-lissajous trajectory that will allow you to kill almost all lateral momentum and leave you falling almost directly into the Sun with mimimal delta-V requirements. It isn’t a quick as firing “straight down” toward the Sun, but it will be several of orders of magnitude less in impulse required. That may not seem significant given the 5 kg payload mass, but consider that the total impulse calculation also requires that you include the mass of all the propellant to carry the propulsion system, tankage, and the propellant itself, which rapidly becomes prohibitive.

As the o.p. has noted, it is literally easier to send a probe straight out of the solar system than it is to go directly down to the Sun.


if you ‘just’ want the book to hit over a million degrees (much higher than the mere 6k on the surface) you need to aim for ~3 solar radii (to hit the corona, which is much hotter than the surface)

to make your periapsis that low, you’ll probably want to have a eccentric enough orbit which takes you very far from the sun

once you hit your high enough apoapsis, you’ll need a lot lot less dV to lower your periapsis to hit the sun/coronasphere

Would someone explain very slowly and using small words why it’s hard to send a rocket directly down (or presumably up) to the sun?

Just getting the book into the corona won’t mean that it’ll reach the same temperature as the corona. The corona has a very high temperature, but it’s also extremely diffuse, which means it won’t have a lot of heat available to transfer to the book.

Besides which, reaching 3 solar radii isn’t much easier than reaching 1 to hit the photosphere, or hitting it dead on.

And on a different note, the object described in the OP has a very low density for something presumably made from leather, parchment, and paper.

Perhaps it is made of materials of which we are not meant to know.

If the rocket launches from Earth, it’s starting off by going at about 30 km/s “horizontally” (that is, in a direction that keeps it at the same distance from the Sun). If you don’t do anything about that, you’re not going to hit the Sun, just fall past it. In fact, that’s exactly what an orbit (like, say, the orbit of the Earth) is: Falling continually, but falling past the object you’re orbiting and continually missing it. If you don’t want to miss it, you have to first fire your rocket to get rid of (almost) all of that 30 km/s, and then fall (almost) straight down (the “almosts” are to reflect the fact that it’s good enough to “miss” by one solar radius, but that doesn’t make much difference).

I suggest that you launch at night so heat won’t be a problem.

The Earth is flying round in a roughly circular path around the Sun. This is the Earths orbit.
If you were to launch an object from the Earth into the Sun in a straight line, the object would still be moving at the orbit speed of the Earth, which is a lot (30km per second ish), and so you still orbit the Sun, just in a slightly different orbit to the earth.

To actually crash into the sun, you need to cancel out the majority of the speed the Earth has given you by launching in the opposite (aka retrograde) direction of the earth’s orbit, and so cancel out its orbital velocity and be pulled straight into the sun by gravity