Japan launches rocket carrying lunar lander and X-ray telescope | Hacker News Reader

Japan launches rocket carrying lunar lander and X-ray telescope

phys.org

249 pointswglb89 comments

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...

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.

One could say it was somewhat too direct :)

It was a highly successful special lunar operation.

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.

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.

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

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.

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...

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.

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

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

The one to watch here is the X ray telescope. JAXA previously lost Hitomi, which was a very promising mission, so hopefully this time they get to use the actual payload.

Hadn't heard of x-ray space telescopes before so this sounded like a cool new thing to avoid atmospheric interference and do better measurements, perhaps even in the moon's shadow to avoid earth-originating noise, but then I looked up whether there have been others and there's a whole host of them: https://en.m.wikipedia.org/wiki/List_of_X-ray_space_telescop...

What would we do with yet another one?

Clicking through to the article about this telescope:

> As the only international X-ray observatory project of its period, XRISM will function as a next generation space telescope in the X-ray astronomy field, similar to how the James Webb Space Telescope, Fermi Space Telescope, and the Atacama Large Millimeter Array (ALMA) Observatory are placed in their respective fields. The mission is a stopgap for avoiding a potential observation period gap between X-ray telescopes of the present (Chandra, XMM-Newton) and those of the future (Advanced Telescope for High Energy Astrophysics (ATHENA)). Without XRISM, a blank period in X-ray astronomy may arise in the early 2020s due to the loss of Hitomi.

–https://en.m.wikipedia.org/wiki/X-Ray_Imaging_and_Spectrosco...

You also made me curious why Hitomi got "lost" (launch failure? Micrometeorite? Hard-/software failure?)

From its article at https://en.m.wikipedia.org/wiki/Hitomi_(satellite)

> [Problems] began with its inertial reference unit (IRU) reporting a rotation of 21.7° per hour at 19:10 UTC on 25 March 2016, though the vehicle was actually stable. The attitude control system attempted to [correct that nonexistent spin, spun it faster and faster, and that broke it up]

What caused this glitch or what was known on the ground at the time (did they know it wasn't spinning but couldn't tell it to stop?) is not mentioned

Edit: oh but it did science in the 36 days that it operated!

> Measurements by Hitomi have allowed scientists to track the motion of X-ray-emitting gas at the heart of the Perseus cluster of galaxies for the first time. Using the Soft X-ray Spectrometer, astronomers have mapped the motion of X-ray-emitting gas in a cluster of galaxies and shown it moves at cosmically modest speeds. [...] [So now we know] turbulence is responsible for only about 4 percent of the total gas pressure.

Is it just Baader-Meinhof at play or are multiple nations running lunar missions at an accelerated rate?

Definitely happening now at an accelerated rate.

Wikipedia has a graph by decade: 12 in the 2010s and 19 already in the 2020s, with 30+ more planned missions planned and already funded.

[0] https://en.wikipedia.org/wiki/List_of_missions_to_the_Moon

Interesting. Very happy to have a reignited space enthusiasm across the globe, just curious if something has developed which is spiking the interest. As far as I understand landing on the moon doesn't contain a whole lot of ROI apart from the mission success itself.

mining rights

There is no international treaty giving you mining rights for landing on the moon.

Rather the opposite. Current international law forbids countries from claiming property rights on the Moon.

What do you mine on the Moon? Moon's gravity may be 1/6th that of Earth's - but that is still a lot to overcome to bring back anything substantial. I keep hearing about Helium3 fusion. But we don't have any commercially viable fusion reactors around. There may be water - but it's likely going to take a lot of processing to extract. What else is there that we can't get on this planet and is worth the cost of lifting from the Moon?

https://www.popsci.com/elements-mine-on-the-moon/

This article doesn't address the nuances - the energy requirements, processing of the ore, etc.

So nothing of immediate or direct use here on earth, just things that may be usable for further off-world construction or (in the case of He-3) might be an energy source someday.

isn't metal in orbit much more valuable than metal on earth? i.e. you can build plenty cheap satellites with it.

This assumes you can refine the ores "in orbit" and manufacture everything "in orbit". This in turn requires a ton of manufacturing on Earth and a lot of launches to move all this stuff off Earth. Not to mention all the supporting industry and infrastructure manufacturing normally has on Earth. Not to mention the R&D costs and staff logistics.

This isn't a video game. You can't just click a button and have an autonomous satellite factory churning out satellites in space. Moving any amount of manufacturing or refining into space is a massive logistics undertaking we haven't even begun to explore. Just because Bezos has a vision of moving the working class off Earth or Musk made some off-the-cuff remarks to rile up his yes-men, that doesn't mean this is something that will happen soon, much less something that will be useful soon.

Japan is, just like with the ISS partnership, a key member of the Artemis accords (IIRC they'll be getting to send their own astronauts to the Moon too, just like how they do to the ISS right now). Thus the increasing activity towards the Moon. I think at this point basically every major country with any sort of space-related industry that isn't Russia or China aligned has signed on and is working on things related to the Moon.

Turns out that the only way to force the US to commit to a destination in space instead of switching between the Moon and Mars every administration was for NASA to turn it into a large international partnership such that it would hurt the next administration's standing to cancel the program.

> was for NASA to turn it into a large international partnership such that it would hurt the next administration's standing to cancel the program.

That's no guarantee. See Jupiter moon exploration - there were _two_ proposed NASA/ESA ones, both cancelled when NASA pulled out. ESA then did their own one (JUICE) and now NASA is doing a couple of its own, too.

What are some of the overall interests for these recent moon missions? In the past it was for manned spy satellite and ICBM programs. Is there a similar national defense parallel being worked on with these efforts?

I think this time the emerging interest is that by leading the effort of and controlling most of the infrastructure for establishing a long term, potentially permanent presence on the Moon, the US can dictate the terms of these first realistic international agreements on the resource rights on foreign bodies. The next closest adversary who is a contender technology-wise for establishing a similar presence is China, so you can imagine that all the issues with them are involved too.

Plus, to a smaller extent there's the idea behind Artemis that all this is a staging ground for our eventual trips to Mars (which, due to the mechanics of it, would have to be a long term thing), where of course the big interest is that it would be another monumental event in human history and politicians would very much like for that to be associated with their name (hell, part of Artemis' motivation was just that they promised to put boots on the Moon before the end of Trump's assumed second term, allowing him to claim to have been the one to oversee America's return to the Moon).

Pretty sure it's a race to land-grab, for future mining efforts and jumping-off points. Probably some science experiments as well. I guess it's a bit like Antarctica, but without the peace and commercial interests.

NASA is planning to build a radio telescope: https://youtu.be/qdJ_gJ_kPEI?si=4MVsL8FtWtkZRI7e

We must not allow a mineshaft^Wmoonbase gap!

in almost a non sequitur, the article reads, "plasmas have the potential for healing wounds, making computer chips...". it made for a good chuckle wondering if the journalist reporting on this was thinking we might harvest some plasma from space

Why from space? We have people donating plasma every day! Silly scientists.

Healing wounds? The author wouldn't confuse the 4th state of matter with blood plasma... right?

Cold atmospheric plasma, used for cleaning wounds.

They sterilize the wound first by putting the object into space. Then, apply the plasma they collected during lift off.

Came for the space talk, stayed for the LLM artifacts.

The attention is all on the lander. But X-ray telescopes are impressive all by themselves. It isn't as easy to manipulate X-rays as light can be using optics. Wishing good luck for both missions.

The 'palm-sized mini rover' fascinates me. A novel solution space for a difficult problem!

https://www.space.com/japan-transformable-moon-robot-ispace-...

With all these countries taking renewed interest in the moon, and analysing what's in the regolith, Sam Rockwell must be getting nervous.

Hey off-topic maybe but why do photos from space always look so fake?

I'm not sure exactly what you're referring to, but, mostly, photos from space are taken differently from photos we're used to taking, like with our cell phones. For example, the Webb Telescope works partly on the spectrum outside of light visible to us, so color has to be added to represent these parts. Other times, we might be seeing a composite image with overlapping parts.

Objects in space are illuminated by a single light source, and are not surrounded by atmosphere. This is similar to the most fundamentally basic raytraced scenes.

To contrast, objects on Earth are often illuminated by many light sources, by the light reflected off of other nearby objects, and even by the light reflected/refracted through the atmosphere the surrounds them. This is very challenging to reproduce in a raytraced scene; so what we are used to is something on the spectrum between realistic and oversimplified.

An oversimplified render of a scene on Earth will have sharp shadows and lack the color reflected off of surrounding objects.

Interesting - I hadn't considered the single-point-illumination aspect.

It also goes both ways: one reason we can have certainty that the Apollo moon landings were real is that the photographs have sharp parallel shadows that could not have been faked using contemporary methods.

> Only four nations have successfully landed on the moon, the U.S., Russia, China and India.

Correction: the U.S., the Soviet Union, China, and India.

That is such a hardcore burn. Yikes haha

Only until recently the Russians were our only ride to the ISS. The US didn't even have a shuttle program...

The US itself still doesn't have a working program, thankfully SpaceX can do it.

The Russians could probably go to the moon again, but there's no real point to.

Russia has tried to go to the moon (Luna 25) like a month ago. It failed.

1. The SpaceX Commercial Crew Program was intentionally the US's plan. That was the expectation of the program (Not that the Boeing side of it looks good to anybody) 2. Russia, just last month, flubbed a rover a couple feet deep into the surface of the moon...so, no if they wanted to, apparently they could not.

Yes. Luna 9 was designed by a Ukranian[1] and launched from Kazakhstan[2]. Calling it a "Russian" accomplishment is pretty silly.

[1] https://en.wikipedia.org/wiki/Sergei_Korolev [2] https://en.wikipedia.org/wiki/Luna_9

To be fair the design wasn't a one man job, and the company is located near Moscow, and Baikonur is an enclave administered by Russia.

I'm not saying Russia was a bit player, just that it's wrong to credit the landing to Russia.

That we can agree on in general, although you can't enter the same river twice.

Cut it.

It is not against China or north korea, but Asian democraties must have their own nukes or the US&|NATO must guarantee we will die with them if they are attacked, namely provide a "nuclear umbrella" via a treaty.

Rockets is only the first step for nuke delivery.

I am uncertain that more nuclear weapons in the hands of more groups will ultimately lead to more safety. While I understand the desire for self defense and MAD, it only takes the dissolving of one nation into a radical group with a truly unhinged leader to then have the power to wipe millions of the face of the earth. Rolling more dice seems like it makes nuclear apocalypse more likely.

>I am uncertain that more nuclear weapons in the hands of more groups will ultimately lead to more safety.

Try to tell Ukraine this, if they had nukes then a lot of people would be alive. But I understand your point if your country already has nukes or it does not have imperialist/aggressive countries as neighbors.

But to get protected from the insane empire neighbor IMo this days you do not longer need super complex rockets, a ton of small drones with dirty bombs in it wold also do a good job preventing an invasion, you need to first prove the world how effective it is.

You people already tried this in 1994. Ukraine gave up their nukes and got invaded anyway. Good luck convincing any other country to give up their nukes.

If NK has nukes then why can't SK and Japan have some too?

I do not question the effectiveness of deterring with nuclear weapons. It would be great if Ukraine had nuclear weapons... for now. How long till a nation state becomes unstable. How long can any entity remain in control of itself. Hell, I don't trust my own country the US to have these weapons and we have the longest track record of not ending the world. But at some point there will be revolution on every country. My source is all of human history. One radical group getting ahold of these weapons with actual intent to use them is all it takes to change the face of the world.

The USSR had lots of nukes. And then it collapsed. Nobody launched the nukes.

I think it's also acceptable for the country to just be advanced enough that everyone knows they could build nukes very quickly if it came down to it.

Japan has the American nuclear umbrella, but it's also obvious to most people interested in the topic that if faced with an existential threat and if for some reason the US didn't fulfill its treaty obligations, Japan could build its own bombs within a year or two.

>"if for some reason the US didn't fulfill its treaty obligations, Japan could build its own bombs within a year or two."

If attacked by nukes they will not be able to build shit.

Typically nukes don't start flying out of nowhere. There's a chain of escalations that leads up to their first strike use.

and of course the attacker would not know that and would give time to japan or south korea for them to acquire nuke tech?

Really?

What? Are you saying that a potential attacker would preemptively nuke Japan before tensions escalate if Japan started developing nukes? Because if so, what ridiculous world do you live in? That'd be like Russia flat out nuking Ukraine last year instead of bothering with an invasion.

What does make you believe all attackers would behave like putin? Do you realize how lucky has been Ukraine in this abomination of war?

I am not sure I am the delusional guy here.

Typically we do not know shit about it. If / when it starts we will.

Which official treaty does give US nuclear umbrella to Japan and South Korea?

I'm not sure of the exact treaty, but every result on Google says that Japan is under the US nuclear umbrella.

Not sure exact treaty for something which should be clear cut?

Really?

Well, since someone else was able to clarify, let's see if you keep up with this approach of asking questions without ever making a meaningful point.

Two individual ones. USA has individual bilateral security agreements with both.

"Treaty of Mutual Cooperation and Security between the United States and Japan" or just the US-Japan Security treaty [0]

"Mutual Defense Treaty (United States–South Korea)" [1]

https://en.wikipedia.org/wiki/Treaty_of_Mutual_Cooperation_a....

https://en.wikipedia.org/wiki/Mutual_Defense_Treaty_(United_...

Thank you. Unlike some posters here (chatgpt?), I don't understand why my google is not giving me any meaningful results, not even on wikipedia.

I would not be surprised to see a Tawainese elite exodus towards those countries.

In recent news; China banned seafood imports from Japan after raising concern regarding the release of nuclear wastewater from Fukushima.

... but that felt like a red-herring. Perhaps this is related.

That was indeed a red-herring as the water was very diluted. China's probably just throwing another tantrum about Japan's position on Taiwan.

Definitely a tantrum. It's diluted tritium. It's almost a shame to throw it away.

It's hard to tell what the tantrum is really about.

Meanwhile Chinese nuclear plants are doing the same but in significantly larger quantities.

https://www3.nhk.or.jp/nhkworld/en/news/20230824_36

How in the world do you see a relation between China banning Japanese fish and the Japanese space agency continuing to do space exploration?

Reply on news.ycombinator.com