Hacker News: dr_orpheus

New comment by dr_orpheus in "Removing these 50 objects from orbit would cut danger from space junk in half"

dr_orpheus — Tue, 07 Oct 2025 15:17:10 +0000

Yep, definitely already on people's minds: "China’s use of its SJ-21 to remove a GEO satellite that had been shedding debris to a very high graveyard orbit in January 2022 has been repeatedly used as evidence that they can threaten other on-orbit satellites" [0]

[0] https://spacenews.com/chinese-on-orbit-servicing-and-debris-...

New comment by dr_orpheus in "Removing these 50 objects from orbit would cut danger from space junk in half"

dr_orpheus — Tue, 07 Oct 2025 15:09:05 +0000

The FAA does have licenses over launch and they are trying to impose rules for upper stages of launch vehicles [0]. The FAA said they would complete these regulations in 2025 [1], but I haven't seen something saying they have gone in to effect yet.

The FCC does deal with disposal requirements for US satellites that are launched. In order to secure a license from the FCC you have to prove that your satellite will meet the latest guideline that it will be disposed of (either de-orbit for LEO, or moved to disposal orbit for higher orbits) within 5 years after mission complete [2]. Unfortunately this doesn't seem to apply to upper stages for some reason even though I would say that it is an orbit object that gets licensed and would "complete the mission" after deploying the satellites and have to abide by the 5 year rule.

[0] https://www.faa.gov/newsroom/faa-proposed-rule-would-reduce-...

[1] https://spacenews.com/faa-to-complete-orbital-debris-upper-s...

[2] https://www.fcc.gov/space/faq-orbital-debris

New comment by dr_orpheus in "New colors without shooting lasers into your eyes"

dr_orpheus — Mon, 21 Jul 2025 15:06:13 +0000

There was a proposed theory on this the spread of absorption created more stability in the power generation of plants over different conditions. This was supposed to be a more important factor than being able to absorb the peak and highest energy.

https://www.science.org/doi/10.1126/science.aba6630

New comment by dr_orpheus in "Athena spacecraft declared dead after toppling over on moon"

dr_orpheus — Sat, 08 Mar 2025 04:36:58 +0000

I spent the last few years building up an immunity to lunar dust powder

New comment by dr_orpheus in "Athena spacecraft declared dead after toppling over on moon"

dr_orpheus — Fri, 07 Mar 2025 23:02:13 +0000

I totally agree with the space is hard, it fails sometimes. I been in the space industry on both the super rigorous high cost, high mission assurance side of things and the low cost commercial launch 10 and hopefully most of them work side of things. The lunar lander is an ambitious first project and two failures in a row is real rough, but definitely happens the space industry in new ventures. I'm sure there are great engineers there and what they are doing is tough.

But...specifically on funding for Intuitive Machines I don't understand how NASA also gave then an IDIQ contract for up to $4.8 billion for lunar communications and PNT services [0] based on the experience of one lunar lander that didn't actually work.

[0] https://spacenews.com/nasa-selects-intuitive-machines-for-lu...

New comment by dr_orpheus in "Athena spacecraft declared dead after toppling over on moon"

dr_orpheus — Fri, 07 Mar 2025 22:52:12 +0000

Never go in against a Sicilian when death (of a spacecraft) is on the line

New comment by dr_orpheus in "Athena spacecraft declared dead after toppling over on moon"

dr_orpheus — Fri, 07 Mar 2025 19:22:15 +0000

Yeah, was cool to see Blue Ghost be successful. And do the point about tall and thin, the Blue Ghost lander is much more squat than the Intuitive Machines landers

https://fireflyspace.com/blue-ghost/

New comment by dr_orpheus in "Athena spacecraft declared dead after toppling over on moon"

dr_orpheus — Fri, 07 Mar 2025 19:19:56 +0000

Yep, most of the previous Mars rover prior to Curiosity did it this way. They had a number of balloons surrounding the rover and landed and bounced along the surface. Then the balloons were deflated in a particular order so the rover ended up the right way up. But for these there was some atmosphere to slow the descent with a parachute and balloons. But for landing on the moon you need the thrusters to slow you down for landing so it can't just be balloons on either side. Presumably you could still use something to slow you down that isn't part of the science mission for the lander that gets ejected right before landing an then let the balloons hit the surface and drop down. But now there are multiple mechanisms and things to do the landing which means more money.

https://www.youtube.com/watch?v=kSbAUtyO7xo

New comment by dr_orpheus in "Starship Flight 7"

dr_orpheus — Fri, 17 Jan 2025 19:31:19 +0000

But don't forget about a local government in Australia fining NASA $400 for littering after debris from Skylab re-entry landed there.

https://en.wikipedia.org/wiki/Skylab#Re-entry_and_debris

New comment by dr_orpheus in "100-MW solar farm just broke ground in Wisconsin"

dr_orpheus — Fri, 15 Nov 2024 18:23:42 +0000

I don't know how common it is, but this is the first time I had seen an announcement of a large solar installation with bifacial modules. I assume that the bifacial modules are more expensive, but I don't know what goes in to the math to make them worth it or not. Does somewhere snowier get more benefit from the bifacial solar arrays because you can get a lot of albedo from the snow?

New comment by dr_orpheus in "Starship's Sixth Flight Test"

dr_orpheus — Wed, 06 Nov 2024 22:42:08 +0000

If you want to look at someone that is further along on a concept like this you can look at SpinLaunch. Exactly what it sounds like with a gigantic centrifuge to spin and throw things really fast. But they are still throwing a small two-stage rocket.

https://www.spinlaunch.com/orbital

New comment by dr_orpheus in "New images of Jupiter"

dr_orpheus — Wed, 06 Nov 2024 21:49:48 +0000

> I think NASA doesn't do a good job sometimes tolerating risk and then everything is treated as needing safety-levels of risk mitigation without considering that a 1/100th cost reduction will not generate as much in parts failures.

I do absolutely understand this impression of NASA. But I also think it gets inflated because the highest profile NASA missions that you hear about in the news are the most expensive and least risk tolerant missions. But there is pretty large spectrum in terms of cost caps and risk tolerance to NASA mission classes. I think generally in order of descending cost/risk tolernace it is: Human Spaceflight, Flagship (i.e. JWST, Mars Rovers), New Frontiers (Juno falls here), Discovery, Explorer, Mid-Explorer (MidEx), Small Explorer (SmEx), Venture.

For an example in the Venture class you can look at something like CYGNSS. Constellation of 8 spacecraft to better understand dynamics of hurricanes by looking at ocean wind speeds. This is done by mapping doppler delay of reflected GPS signals off of waves in the ocean. Important science, super cool technology with mostly automotive grade parts. ~$150 million for the whole mission that lasted about 7 years.

New comment by dr_orpheus in "Starship's Sixth Flight Test"

dr_orpheus — Wed, 06 Nov 2024 21:11:15 +0000

For context on JumpCrisscross's comment in this thread: the 4 hours is between two separate launches on two separate rockets. This is absolutely not refurbishing and launching the same rocket 4 hours apart.

Seems like the actual record for turning around the same booster is 21 days, which is still quite impressive.

https://www.teslarati.com/spacex-falcon-9-new-booster-turnar...

New comment by dr_orpheus in "New images of Jupiter"

dr_orpheus — Wed, 06 Nov 2024 20:57:19 +0000

Yep, they do! I had some of this discussion on a thread talking about the Mars helicopter here that Goddard does a lot of radiation testing on commercial chips.

https://news.ycombinator.com/item?id=39175423#39182421

Lots of the new space, and smaller satellite companies use a lot of commercial parts. A lot of the flight data has shown even better results than the radiation testing (possibly due to added stress of testing at higher rates vs low rates over longer mission duration).

Generally speaking most of this is in LEO with a pretty low radiation environment. Whereas the area around Jupiter is one of the worst radiation environments in the solar system due to the radiation belts (like the Van Allen belts on steroids). This page on the Juno Radiation Vault says the spacecraft is exposed to an anticipated 20 Mrads of radiation. Whereas spacecraft in LEO are exposed to 0.1-10 krads per year depending on the orbit.

Also a fun fact, this is with Juno trying to limit exposure to the radiation belts as much as possible. [1]

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

[1] https://en.wikipedia.org/wiki/Juno_(spacecraft)#/media/File:...

New comment by dr_orpheus in "New images of Jupiter"

dr_orpheus — Wed, 06 Nov 2024 16:52:19 +0000

Yeah, you got a lot of it and the ripple effect of things that go out from it. In addition to the extra mass of the camera and solar arrays, there is extra mass for the harnessing to connect the camera to the computer and engineering design for that as well. Integration of anything else on the spacecraft will have to go through Failure Modes Effects and Criticality Analysis (FMECA). Basically, this gets in to pretty detailed circuit design analysis and makes sure that any failure on the camera itself (like a short circuit or babbling idiot data bus) won't impact the rest of the spacecraft.

Potential cost of increased storage onboard the spacecraft if it is significant data volume. Cost of downlinking the data to the ground, time on the DSN is expensive. I think the cost data sheets for DSN usage are online and it depends on data rate, what dish you are using, etc. but costs for usage are on the order of thousands per hour and data rates from Jupiter are pretty slow.

The cost of the camera itself is likely on the order of a couple hundred thousand. I've seen similar costs for small radiation hardened cameras and star trackers. The difference in parts cost for some things can be absolutely insane. Passive electrical components certainly cost more, but for active circuits it can be insane. A radiation hardened equivalent of a $20 FPGA can be something like $20,000.

All told, cost of integration and use over the mission is likely at least a few million. But on a $1.1 billion mission it still doesn't seem like a lot.

New comment by dr_orpheus in "New images of Jupiter"

dr_orpheus — Wed, 06 Nov 2024 16:25:58 +0000

Yep, for reference Europa Clipper is 6,065 kg [0]. It is an absolutely massive interplanetary probe. It is getting close in size to some of the largest GEO communication satellites. And to get it out to Jupiter they definitely need some of the gravity assist trajectories.

On the opposite end of the spectrum, New Horizons was only 478 kg [1] and still holds the record for the fastest thing ever launched from Earth. It also did a gravity assist flyby around Jupiter and it still took 9 years to get to Pluto.

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

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

New comment by dr_orpheus in "New images of Jupiter"

dr_orpheus — Wed, 06 Nov 2024 16:12:52 +0000

Not a silly question. I don't think the images are actually cropped. JunoCam is described as a "push broom" imager [0]. The camera takes pictures as the spacecraft turns. So it's more like you are looking at a stitched together panorama and not a cropped version of a larger image.

[0] https://en.wikipedia.org/wiki/JunoCam#Design

New comment by dr_orpheus in "World's First Wooden Satellite Heads to Space in Mars Exploration Test"

dr_orpheus — Tue, 05 Nov 2024 15:39:24 +0000

> Wood should not be damaged by temperatures high enough to kill living cells

Yep, in NASA's planetary protection guidelines they have bakeout timelines specified for microbial reduction at temperatures between 112C and 155C. There are a number of other cleaning and sterilization methods in there as well.

[0] https://planetaryprotection.jpl.nasa.gov/resources/img/conte...

New comment by dr_orpheus in "In a rare disclosure, The Pentagon provides an update on the X-37B spaceplane"

dr_orpheus — Mon, 14 Oct 2024 16:52:57 +0000

Yep, and you can find lots of commercial companies that are doing this

https://exoanalytic.com/space-domain-awareness/

New comment by dr_orpheus in "Gamma radiation is produced in large tropical thunderstorms"

dr_orpheus — Thu, 03 Oct 2024 21:50:07 +0000

Amazing, and so is the associated article: "In a recent piece on red-giant star Mira, we rather foolishly suggested that the "comet-tailed" body was travelling across the heavens at roughly 150,000 times the speed of the average sheep."

https://www.theregister.com/2007/08/24/vulture_central_stand...