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Comment by nexus6 | Hacker News Reader

Is there such a need for a heavy launch rocket to launch routinely?

SpaceX already launches multiple times per month just to maintain Starlink. That will be much cheaper with Starship while enabling larger and more capable satellites. In fact, it's likely that one of the reasons SpaceX built Starlink is to create their own customer (and spur competitors) to plausibly use a significant fraction of Starship's capabilities. None existed at the time.

In the near term the biggest reason to do multiple launches in a day will be orbital refueling. This is required for sending much, much larger payloads to the Moon and Mars. It will require on the order of 10 launches to fuel up one moon lander in orbit, and obviously doing that as quickly as possible will be beneficial. NASA has already committed to this plan for Artemis.

> It will require on the order of 10 launches to fuel up one moon lander in orbit

Require, or just make comfortable? Saturn V had the lift capacity of "only" a couple of Falcon Heavies, but was enough to carry astronauts, a car, a lunar lander with enough fuel to take off, and a command module.

We're not trying to do Apollo again. That would be easier, but we want to build a base this time. For that we need to send a lot more mass and it needs a lot more fuel.

Require. I answered that in this same subtopic.

It's necessary because the Starship upper stage is so heavy. With a non reusable upper stage Starship's capacity would be enormous.

Also because of the Lunar Gateway part of the plan. That pretty much just serves to waste fuel and funnel taxpayer money to the companies funding several congressmembers' election campaigns.

Is that true? SpaceX [0] gives the capacity as 150t reusable or 250t expendable, which is significant, but not enough to make one "enormous".

If you really got order-of-magnitude gains from an expendable upper stage, it wouldn't be that exciting to have reusable rockets (which are more complex and still only fly one order of magnitude more times) in the first place.

[0] https://www.spacex.com/vehicles/starship/

If the upper stage wasn't designed to be reusable, it'd probably have a lot less structural dry mass - no heat shield, no fins, possibly different geometry (depending on how much volume they wanted). It might also be possible to drop the sea-level Raptor engines and just use the more efficient vacuum Raptors. I don't think you'd get an order-of-magnitude difference, but it'd be significant, especially for higher-energy trajectories than LEO.

I don't understand why they don't make such an upper stage. It would allow them to refine the booster design and catch logistics while also launching payloads.

My guess would be that it would take too much extra design work. Making the current upper stage reusable is necessary for the HLS contract anyways, and they've got a lot of work to do already on refining the heat shield & fin protection, enabling landing, and working on propellant transfer.

They are making an upper stage with no fins or heat shield. It's called HLS. But they don't need it just to launch payloads to orbit. Starship has such a bonkers huge payload capacity already that it's plenty for now. Nobody is asking for more yet. Testing Starship reentry is super important too, so it makes sense to do it on every launch until it's perfected.

It's a mandate for the next Artemis Mission. [1]

The HLS (Spaceship) will need many refuels at orbit in order to get to the Moon and back. That means at least a dozen of fully-loaded Heavy launches to LEO just so each one of them can load a bit of fuel into HLS. The fuel in orbit can't sit idle for too long, or it deteriorates; I haven't found a limit on days for that, but a week-long launch window is considered a dealbreaker, we're talking a dozen Heavy launches in a week.

It's either a short launch window, or at least 6 Starships built and launched twice in ~10 days. Don't count out on SpaceX building 12 Heavy Starships just for that Artemis mission.

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

Needs tend to develop once the means are there.

200 years ago, there was no need to use electricity. 100 years ago, there was no need to use a programming language. 30 years ago, there was no need for gigabit wireless Internet.

Nobody will ever need more than 640k of RAM.

Or perhaps earlier and closer to the heart of USA's citizens, 300 years ago, there was no need for rail lines and trains.

> Needs tend to develop once the means are there.

Counterexample: space stations. We've had small manned space stations for decades now, but no real application for them. They're national prestige items only.

Because launch cost is expensive. There are a lot of interesting things we can develop in zero gravity if the cost per pound was cheap.

Not true! The ISS has functioned as an outpost for science- 3,000+ experiments and counting

https://www.nasa.gov/missions/station/five-space-station-res...

And most importantly for anyone who cares about space the way Elon claims to: The ISS has done pretty much all the research we have on how humans survive in space.

The hazards of living in zero-G were understood at the end of the Mir era.

This feels like tautological reasoning. Since you said, "tend" - are there any counter examples that you can think of?

Some marginal ones.

We have the means to build pyramids or moa statues (Easter Island-style) much more quickly and efficiently that the ancients did, but we don't feel the need anymore.

If satellites don't have to worry as much about weight constraints they can be made cheaper and quicker. Space missions can become more routine.

If we want to establish long term bases on the Moon or Mars then yes, you need not only to send crew and habitation modules but ongoing supplies and equipment.

Other use cases include launching and maintaining satellite constellations (Starling / Starshield), and launching singular large payloads like space telescopes.

Even for smaller payloads, having both the first and second stages be reusable will reduce launch costs.

Yes, to do anything at all in the rest of the universe.

We are insatiably curious explorers. The cosmos calls to us. Many are willing to do anything they can to answer that call.

Yes, obviously.

It takes a heavy launch rocket to launch heavier things into space or missions, refueling, and to goto other planets.

Think about it, Starship enables a new era of military dominance in space. Military stuff is notoriously heavy.

Besides, Elon is the first to go after supervillain territory.

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