hckrnws

Landsat is one of those (for now, bygone) projects that the US Gov (and EU!) ran to the benefit of basically everyone. Imagine the benefit for any kind of land planning to have access to this data. USGS.gov has tons of soil and topology data, thanks in large part to this program, and essentially free for all.

Other programs we just never think about include NOAA state of the art weather from which all "local weather" is possible, free and open air navigation charts, and free air traffic control. Think about how, scattered across the entire continental USA, there are a dense network of radio towers broadcasting homing signals so that any aircraft can navigate safely without subscription or cost.

And then of course we have GPS.

It's just unbelievable the things we've built and essentially given away for the benefit of humanity. Apolitically, I look forward to an era where we can do that again (without living on borrowed time, if possible).

It is not "given away". It is an investment into economy that I'd imagine pays out very well all things considered.

For those that remember the first iteration of Google maps. The satellite view was all Landsat imagery save for Massachusetts that used their higher resolution public aerial dataset.

Most innovation is military innovation, if only by proxy.

*military and space

The latter often is just for the former but with some PR. Not all but a significant amount. The first US and Soviet astronauts were flying ICBMs. Hubble is leftover spy satellite gear and two more leftover similar satellites were gifted to NASA in recent history. The Space Shuttle was intended to capture foreign satellites for the CIA. The Soviet Union had small space stations that carried cannons. And of course, we both nuked space just to make sure that worked.

Clearly we do a lot more commercial space at this point but the lineage is there.

Yeah but there is no space war (yet) at that time

In 1990 I was super excited to have my high school work experience application accepted to CSIRO in Macquarie Park, only to find when I turned up that I’d spend the whole boring week cataloging magnetic tape from these dull satellites Landsat 4 & 5. The only time my greybeard supervisor seemed remotely animated was when he started imagining what imagery 6 & 7 would send back.

How wrong I was; what this now greybeard wouldn’t give to rummage through that lab again.

RIP #7.

I don't understand this: article states it will drift as space debris for 55 years (!) before reentering the atmosphere? Why isn't this done immediately by just lowering it's orbit even further and letting it burn?

> The final steps included carefully lowering the satellite's orbit to decrease the risk of collisions and ensuring that all energy sources, such as fuel and batteries, are depleted to prevent the satellite from accidentally turning back on or creating debris. As Landsat 7 begins this decommissioned phase, it will drift silently in orbit for about 55 years before reentering Earth’s atmosphere.

> "Why isn't this done immediately by just lowering it's orbit even further and letting it burn?"

It'd take a very significant and expensive amount of fuel to "just lower" the orbit! From its 700 km orbit, it'd cost (by my estimate) roughly 300 m/s, or on the order of 10% of entire satellite mass, to perform this lowering burn.

It's not at all standard practice to deliberately dispose of satellites this way (SpaceX is a major outlier), and wasn't even on the radar in the 1990's, when this satellite was being built.

(Here's an anchoring point: the projected cost for the propulsion to "just" deorbit the International Space Station, at the end of its operating life, is $1.5 billion [0]).

[0] https://spacepolicyonline.com/news/nasa-iss-deorbit-vehicle-...

> (Here's an anchoring point: the projected cost for the propulsion to "just" deorbit the International Space Station, at the end of its operating life, is $1.5 billion [0]).

That's under 2% of the total cost, that's not too much, if you compare it to the rest of the TCO, and not how beneficial would it be.

Should use the ISS as the base mass for a EM launcher. Seems nuts to waste so much on that existing potential energy.

ISS is in a bad orbit for this sort of thing: halfway between the best orbit for Baikonur and the best orbit for Kennedy, it was a compromise which was okay because it wasn't getting that much traffic, so the penalty didn't amount to much at the scale of the budget. Using it as an orbital way-station will end up paying that compromise penalty a whole lot of times on all the launches up to the station, driving up the total value of the orbital penalty. If you are doing something big enough in space that you can afford to keep the ISS in operation (1) then you are probably better off building your own platform in the right orbit for your launch site. (2)

Also, repeated dockings and undockings (as you assemble the mass driver and then use it) will ruin any microgravity experiments you might want to run, so you can't really combine "base station for deep space exploration" and "science lab" missions, you really need the station to be focused on one or the other.

1: The main problem ISS has is political, not technological. By design you need the US and Russia to cooperate to keep it operating, and that made a lot of sense in the 1990s, and has fallen apart over the past decade.

2: Orbital plane changes- to move ISS to the right orbit for a specific launch site- are hideously expensive in LEO. GEO satellites often find it cheaper to raise their apogee out to near the moon, make the necessary plane change way up high, and then drop the apogee again when they get to perigee, rather than make the plane changes in LEO. (ISS can't do that.)

It's in the ideal orbit for Baikonur. It's much, much easier for a low-latitude launch site to reach a high-inclination orbit than vice versa. This is especially true for Baikonur, where the available inclinations are restricted by human habitation and foreign countries downrange. Hence the minimum inclination is 51.6 degrees (which is where the ISS is) despite the launch pads being at 46 degrees latitude.

You are correct, I had remembered the details wrong- ISS and Mir and Salyut 7 all have the same orbital inclination, so that's clearly the best orbit for Baikonur. So if you were doing your mass launches from Baikonur you would not pay much of a penalty. From KSC, though, you'd almost certainly want a lower inclination to get more payload up.

Really, you pay the same penalty launching to 51.6 degrees regardless of whether it's Baikonur or KSC. But you're totally right, you can do even better by launching to lower inclinations out of KSC, which can go down to 28.6 degrees.

> It's not at all standard practice to deliberately dispose of satellites this way (SpaceX is a major outlier), and wasn't even on the radar in the 1990's, when this satellite was being built.

tbf it is now a standard practice (quite literally: it's part of ISO24113) for satellites in LEO to lower the orbit to allow reentry via natural orbital decay within 5 years or less (recently reduced from 25 years or less). Your average CubeSat launched into the lower reaches achieves this naturally through atmospheric drag without propulsion, but anyone sticking their satellite at 700km needs propulsion and sufficient total impulse to be able to conduct a deorbiting mission at end of life.

But yeah, certainly wasn't in the 1990s when congestion of LEO wasn't a consideration

1.5 billion??? if starship from space x is ready by the end of service. can we make it cheaper using starship? using robot arm or just push it to designated landing point with starship

It seems to be a common misconception that lowering an object's orbit is much easier than raising it. I guess because it feels like it is just floating up there and gravity can do most of the work to pull it down if you give it a little nudge. In reality the energy required to lower the orbit is about the same as the energy required to raise it. In both cases you need to change the orbital velocity.

then just push it out of orbit

This is basically what they’re doing; most of the cost is for SpaceX to modify one of their existing vehicles into the USDV. You probably underestimate how much energy is needed to deorbit ISS.

I wonder what the real costs are and what is taken as profit

still better than competition

you would need to carry enough fuel on board to get rid of most of the velocity obtained during orbital insertion. That is lots of fuel

Related: End of an era: Landsat 7 mission takes final images (273 points, 8 months ago, 48 comments) https://news.ycombinator.com/item?id=41663465

We're reaching a history / pre-history moment where the entire earth's history will be available as a high definition orb with video feed, scrollable through time.

Aww. That was a primary source of data for my undergrad and grad studies of geography. Everyone remembers their first false colour composite. Seeing the vegetation just pop. Then you’re hooked.

Do these things continue to do their work, picturing and transmitting data, even after being decommissioned? Or do they need constant human attention and thus go silent?

Oh, good, there's still Landsat 8 and 9 working. The title suggested that perhaps this was part of a plan to cut down observations of climate change.

not so good, see: https://news.ycombinator.com/item?id=44190279

I loved how early Landsat imagery featured in the movie Kong: Skull Island about finding a mysterious lost island in the Pacific.

Off topic to the thread, but that was a surprisingly good movie!

That side by side image of Vegas shows they've shrugged off all the losses of the GFC.

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I'm a LANDSAT fan to the extreme. But I suspect that Planet will step up and provide a (subscription based) alternative, at zero up-front cost to the US Government. Over short time horizons, this is cheaper. Over long ones ... who knows?

I think the main thing is the US government doesn't want to subsidise anyone studying it. Sure even without LandSat hardware the US Government can get the data from Planet and dozens of other commercial EO constellations, for free from ESA's Sentinel programme and random academic and small country CubeSat projects. But will they?

The “Planet” being L3harris/peter theill?

https://www.planet.com/

I couldn't find anything that suggests where their major profits (≈ major income) would come from. I assume finance: Hedge funds? Insurance industry?

Are government and science users just secondary sources of income?

I'm fairly sure government is a primary consumer, up there with hedge fund types. They do some primary analysis, but the big market is in "processed" data, if I understand it correctly, so people will buy this data wholesale, hook up a subscription API, and feed it directly into their analysis pipelines.

https://www.planet.com/company/customer-stories/

Government users includes the defence sector...

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The climate truths remain inconvenient.

Maybe it could be a boon to the sentinel program in the same way as the current administration strengthened the European defense posture, by weakening our own. If that happens it could actually be good, because America military will no doubt spend as much as it can on science as soon as they get debt back under control. Sadly that seems like it won’t happen in 2025, but with enough growth maybe by 2030 we’ll be back, and better.

Trump is trying to kill it, but at the end of the day congress decides how much they want to incorporate the president's request into the budget. They were pretty happy to ignore them in the past so I wouldn't be surprised if that streak continues, with some token cuts.

The way things are right now, the president decides how much he wants to actually spend out of what Congress allocates. It doesn't matter if Congress funds Landsat Next, if the administration refuses to spend that money.

>They were pretty happy to ignore them in the past

Sad to say, with that budget bill waiting to be pass, this time I thing you may be wrong. In any case Trump is ignoring what Congress passed in the past and even now, I doubt that will change.

(I really hope you are right)

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