Piscator

I would love to see missions like these. Your timeline might not work out though. I have no idea when Jupiter would actually be in a suitable position for a gravity assist, but to launch probes in two opposite directions you would presumably also need Jupiter in two roughly opposite spots along its orbit. So it would seem more realistic for your "second" mission to launch in 2036 (assuming your launch date in 2030 for the first mission works out), three years after the "third" mission.

Let's try to avoid steering into ad hominem territory, but so far problems with the Raptor engine seem to either originate from side effects of being struck by debris, likely issues with the fuel supply or not being started up at all due to faulty attitude control. I don't see how testing the engine for minutes instead of seconds would solve these issues, since Raptor seems to be quite reliable once it's running.

Repeating that something is a mistake over and over again doesn't make it a mistake though.

In fact, the main form of propellant you lose is the bombs. Which, as has been pointed out, are used very inefficiently.

I guess they could try it, but they would end up with a bunch of satellites with reduced life-expectancy (very reduced if they don't dispense properly). I'm not sure that's a good deal.

If you're building this many satellites you probably get a few rejects you can use to test the dispensing mechanism. I agree though that it wouldn't be very sensible to release operational satellites on a suborbital trajectory and that trajectories will likely remain suborbital until a deorbit burn is demonstrated.

To expand on point 2 in the start post, using milligrams of antimatter in a photon drive probably won't get you to Mars. Assuming a 10 ton spacecraft, every milligram of emitted photons will only accelerate you by about 3 cm/s. To reach Mars, you would be well into gram territory.

3. You are a tardigrade. Ideally made from antimatter. 4. You're buying the trip from someone who accepts antimatter as a currency.

A higher atmospheric pressure would not necessarily lead to heavier winds, since wind speeds would likely be lower. Atmospheric circulation is mainly powered by the sun, so if you have to move a larger amount of atmosphere with the same amount of energy, it would move more sluggishly. On Venus, for example, wind speeds constantly decrease with rising atmospheric density.

While it is highly doubtful that any rain of sulphuric acid reaches the surface (since it would boil away long before), the sulphur compounds in the Venusian atmosphere still contribute to its overall corrosiveness in a major way if you can believe this paper. Unfortunately, it doesn't say anything about titanium, but any copper wiring would have turned into a mass of dendritic copper sulphide crystals long ago, it appears. Aluminium seems to be fairly stable but traces of alloyed magnesium oxidize quickly. Steel in general doesn't fare very well either, slowly reacting with the simulated atmosphere to iron and chromium oxides and nickel sulphide, depending on the original composition. PS According to the follow-up study, titanium seems to be quite stable under Venusian surface conditions.

Methane is actually non-toxic, but I would keep an eye on the hydrogen cyanide, carbon monoxide and other trace components of the atmosphere. Also, some of the tholins on the surface are probably not exactly healthy.

How would you arrage a natural number of digits in a grid with a non-natural number of rows and columns? The idea behind the Arecibo message seems to be that you send out a signal with a number of digits that immediatetly shows you how to arrage it into a two-dimensional pattern since there are only two neat ways to do it (73x23 and 23x73). If you received a message with 4463 digits (the last one a little smudged) you wouldn't have an immediate clue how to arrange the content of the message. Even if you made a grid with pi columns work somehow. You would have to try out any number of mathematical and natural constants first. And more importantly, 1420.4 is only a natural constant if you happen to use the second as a unit of time anyway.

I guess they could either keep more engines burning during separation or delay the full restart until the fuel has had time to settle again. Might be easier to just change the flight profile than rearrange the plumbing. Might be not though, in the long run.

You can also see quite clearly in the video that it's only the front half that is tumbling.

Would have got that right. The rescheduling to Saturday fits my personal schedule perfectly but I hope they don't have to postpone it any further.

Or maybe they're afraid of succeeding. A starship drifting out in the ocean might be more trouble than its worth. After all you would have to scuttle it manually somehow. The thing seems to be quite resilient.

I suspect thermal radiation. Planets are slightly warmer than their surroundings due to radioactive decay, retained primordial heat etc so their infrared radiation should be detectable.

As far as I know, the charges worked immediately. It's just that it took the vessel 40 seconds to sufficiently depressurize to finally loose enough rigidity to be torn apart by aero forces.

They also explicitly mention star spots in the article which would be a fair bit cooler still.

As far as I undestand it, there is considerable overlap between both systems. The booster and launch infrastructure is always the same and a dedicated tanker starship would be needed for both mission types as well. At the point when people land on the moon in starship you're three quarters done with the Mars variant of the system as well.

If it's real, the heat shield tiles seem to have held up rather well. At least compared to the engines.

If you're talking about the featureless orange ball on page six, I'm pretty sure that's supposed to be Titan.

There was a discussion about them recently in fusion thread: Point 1) was explained in detail in the videos linked in that thread. It didn't raise any serious red flags for me at that time, but since I'm not an expert either, this probably doesn't mean very much. Basically, using pure deuterium as your source material (since you would be breeding your own He-3) would be a great advantage as you could skip dealing with the expensive and radioactive Tritium entirely. As for point 2), with any claim that seems too good to be true, there is a substantial chance that is. They wouldn't be the first to fake results, attach som blinkenlights to a spool of copper wire and call it a free energy machine. If their project is technically sound though, there's still the chance that it doesn't make economic sense. The devil is often in the detail, and maintaining your He-3 breeding infrastructure might simply be much more expensive than expected.

Pointing out that this drive would violate the third law seems a bit besides the point when the whole thing is based on the assumption that it is actually only a guideline. I think it highly unlikely that they're onto something, but it's at least nice to see their theory tested. No need to argue about it. Just let the universe be the umpire.

Well, assuming your smart cooling system works, you could just add a pair of giant stylish angel wings to your suit to increase the radiative surface. Or you could carry an equally stylish parasol.