Hacker News Reader

Comment by riffraff | Hacker News Reader

The trajectory of this missions is really cool [0], basically it will use both the earth _and_ the moon to slingshot itself and then approach the moon in a sort of tangential path.

As I understand it this means the mission will take quite a bit more time than "usual" but save a lot of power.

[0] I'm on mobile, but this looks like a decent representation https://twitter.com/TitaniumSV5/status/1695724234339954779?t...

View on HN

Landing mechanism is cool too. The lander has deformable metallic sponge balls on the legs, hits the soil at its "heel" and tip forward[1].

Official reasons given is it allows reduction of structural margins, physical interferences and tipover risks on inclined surfaces, which seem to make sense. Maybe it's just me that it looks a bit like someone had to have a spacecraft that lands like the Space Shuttle with engines pointing back.

1: https://www.isas.jaxa.jp/feature/forefront/files/201912_1.jp...

That’s pretty much my standard landing method in Kerbal.

Descend vertically to keep from having to worry about balancing a bunch of thrusters.

Then, tip over, hopefully in the right orientation and gently enough to not blow up.

Slingshot analogy animation: https://en.m.wikipedia.org/wiki/Chandrayaan-3#/media/File:An...

Gravity assist or gravitational slingshot [1] is a specific type of maneuver that's different from the Hohmann transfer that Chandrayaan-3 is seen taking in your video.

[1] https://en.wikipedia.org/wiki/Gravity_assist

yeah but notice the JAXA one is different, since it approaches the moon twice.

It starts sort of the same way, but then it uses the moon's own attraction to project itself much further out and then come back approaching the moon in a different way.

ISRO missions to Moon and Mars leveraged Sling-shotting (saves on Fuel and weight of the same to be carried). The Russian probe took a more direct approach landing to the moon.

ISRO missions leveraged Hohmann transfers to gradually raise the orbit. It does save on fuel using the Oberth effect. It also has somewhat less uncertainty. However, they were not gravitational slingshots. Have a look at the tweet linked by the other commenter - the probe approaches moon twice. The first approach causes a rather drastic change in velocity and trajectory. It's unlikely that such a change comes from the probe's thrusters alone. I assume that the second approach and capture is somewhat mild (tangential as the other commenter put it).

In comparison, the Chandrayaan and Mars orbiter missions approached their target only once. And the insertion was also somewhat drastic, with a long retro-burn.

One could say it was somewhat too direct :)

Of all the recent failures of moon landers, Luna 25 is the most intriguing one. It failed simply because the retro-burn continued too long. It was a simple timed operation, unlike all the complex logic that goes into landing. Makes me wonder about the state of the Russian space programme.

This wouldn't be the first time that they've lost a major mission due to a similarly simple root cause: https://en.wikipedia.org/wiki/Polyus_(spacecraft)

The most recent former head of the agency has apparently expressed skepticism about the US moon landings in 1969 and also has a degree in economics. Allegedly the program has been hollowed out by corruption. Perhaps someone more qualified to comment could shed some light on this?

If you mean Dmitry Rogozin, then yeah, he was a total dick (a part of which he has allegedly lost recently in Ukraine) who peddled all sorts of lies and oversaw the decline of Russian space capabilities.

I wouldn't be surprised if he expressed doubt over the Moon landings considering that he was also the one to push the absurd claim that the hole that had been drilled into a Soyuz was sabotage done by a space-crazed American female astronaut.

The Russian space program is a real mess and a shadow of what it once was.

It was a highly successful special lunar operation.

https://nitter.net/TitaniumSV5/status/1695724234339954779?t=...

Reply on news.ycombinator.com