Poll

Who will win the war between Space Tugs and Small Launchers?

Space Tugs
21 (72.4%)
Small Launchers
8 (27.6%)

Total Members Voted: 29


Author Topic: Who will win the war between Space Tugs and Small Launchers?  (Read 17689 times)

Offline Tywin

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Offline Blackjax

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Quote
Italian firms D-Orbit and Group of Astrodynamics for the Use of Space Systems (GAUSS) as well as U.S. companies Momentus, Northrop Grumman Innovation Systems and Spaceflight Inc. have developed, manufactured, tested or flown orbital transfer vehicles. Seven additional companies are preparing to enter the market with initial flights scheduled in the next three years. The companies are: Atomos, Exotrail, Firefly Aerospace, Launcher, Space Machines, Exolaunch and Impulse Space.

Interesting, there are even more than I realized in the works. The wider the array of technical and service offerings, the more likely it is that someone will dial in the right mix.  I do agree with the article that this all depends on the success of Starship and other offerings bringing launch prices way down.

Offline high road

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Most orbits that would make the extra cost of a smallsat launcher acceptable, would be too much for a space tug to get to from another orbit IMO. Space tugs could be better used as mission extention vehicles.

I do think both will service very small markets, and that seems to me the main reason why they claim that constellations, the only market segment with considerable growth at the moment, would be their main customer. In reality, constellations will not make extensive use of either smallsat launchers or space tugs.

Offline Vahe231991

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Most orbits that would make the extra cost of a smallsat launcher acceptable, would be too much for a space tug to get to from another orbit IMO. Space tugs could be better used as mission extention vehicles.

I do think both will service very small markets, and that seems to me the main reason why they claim that constellations, the only market segment with considerable growth at the moment, would be their main customer. In reality, constellations will not make extensive use of either smallsat launchers or space tugs.
Space tugs might potentially deorbit a handful of Cubesats launched by small launchers if those CubeSats suffer a failure in their communications apparati. However, large space tugs will win if they dock with derelict Soviet-era ELINT satellites to allow those satellites to decay from orbit over the course of two weeks.

Offline RoadWithoutEnd

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Small launch providers that fail to upgrade to big launch tend to chase markets that inevitably lead to solid fuels and expendability.  They need high sustained margins to handle their fixed costs, and that puts them on the well-trod downward spiral of military niche contracting.  Meanwhile, large (especially reuse-enabled) launchers can apparently (knock on wood) build entire infrastructures around their lower-percentage but higher-absolute gains, so tugs are a natural step for them.

Vicious vs. virtuous cycle.

So tugs it is.
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Offline DeimosDream

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Option #3: both survive in their own niche and increase in flight rates. No ‘winner’.

Offline TrevorMonty

There is market for both. Spacetugs and their payloads are still relying on rideshare launches. If spacetug goes up with satellites then that extra is HW and mass which adds to cost. Reuseable spacetugs need to refuel, which requires visit to fuel depot with additional DV they then need reliably dock with satellite and transfer it to destination orbit. Lot of extra steps, time and fuel involved.

Dedicated small LV and medium RLVs will deliver satellites directly to destination orbit with satellite operator dictating launch schedule.

Offline Vahe231991

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Russia could build a batch of 150 space tugs to be launched into space aboard the Soyuz-2.1a to dock with derelict Soviet-era communications satellites in order to deorbit those satellites.

Online trimeta

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Russia could build a batch of 150 space tugs to be launched into space aboard the Soyuz-2.1a to dock with derelict Soviet-era communications satellites in order to deorbit those satellites.
I could find unicorns dancing in the Falcon 9 flame duct, too. Or at least, I'd be far more likely to discover said mythical equines than Russia is to spend money cleaning up their historical space debris unless international action forces their hand.

Offline deadman1204

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Most orbits that would make the extra cost of a smallsat launcher acceptable, would be too much for a space tug to get to from another orbit IMO. Space tugs could be better used as mission extention vehicles.

I do think both will service very small markets, and that seems to me the main reason why they claim that constellations, the only market segment with considerable growth at the moment, would be their main customer. In reality, constellations will not make extensive use of either smallsat launchers or space tugs.
This.
I really don't think its a "war" with a binary choice. Tugs are not the end all answer to everything.

On their own, tugs add more complexity and risk to a mission, but if we lump them in with general satellite servicing, they will have a place.

Offline Tywin

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Offline TrevorMonty



Another example of space tug domination...

https://twitter.com/GoToImpulse/status/1747646045549744318

Releasing product doesn't mean it will be successful and upset market. Given size of Helios it will be the only payload on LV which asks question who will be paying for LV.

Where satellite or satellites all belong to single customer they will buy Helios and book ride. In case of various satellite owners then Impulse would need to book LV and run their own Transporter type mission.

Launch infrastructure needs to support fuelling Helios with Methalox just before takeoff. LV providers won't do this for free and will likely demand maintenance fee. There is also risk to LV and pad from explosion that could originate for Helio fuel leak. Losing LV isn't big deal if customer is paying but damage to pad is another thing altogether.

If there is strong business case for Helios then most LV providers could quite easily build a 3rd stage for their LV.  RL have already done this with Photon and may yet do one for Neutron.


Offline Jim

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Who will win this war in the future?


There is no war.  There will be no tugs until at least there is depots.  But why have a separate tug?
« Last Edit: 01/19/2024 01:21 pm by Jim »

Offline chopsticks

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This could potentially be devastating for ULA. They love to talk about high energy, but if you have a reusable LV optimised for LEO (hard to make a reusable LV for high energy without refuelling) and cheap tugs, you basically take all of the argument out of ULA's talking points - the exception being an expendable high energy LV can deliver a payload to GEO quicker than a tug can dock. I don't know how necessary that would be though, that is, to get a sat to GEO asap. Obviously, depots will be needed to make this architecture work at low(er) cost.
« Last Edit: 01/18/2024 05:45 pm by chopsticks »

Online DanClemmensen

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This could potentially be devastating for ULA. They love to talk about high energy, but if you have a reusable LV optimised for LEO (hard to make a reusable LV for high energy without refuelling) and cheap tugs, you basically take all of the argument out of ULA's talking points - the exception being an expendable high energy LV can deliver a payload to GEO quicker than a tug can dock. I don't know how necessary that would be though, that is, to get a sat to GEO asap. Obviously, depots will be needed to make this architecture work at low(er) cost.
If you have a super-cheap two-stage fully reusable superheavy that can put (say) 200 tonne into LEO, then its payload can be a 100-tonne expendable kick stage with a 100-tonne actual payload. I think this beats Vulcan Centaur, except for the minor fact that it does not exist. Think of it as a one-off "tug".

But this is completely off-topic for this thread. This thread is supposed to be about using a tug to allow one rideshare to hit multiple orbits to compete with multiple small launchers.

Offline deltaV

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1. https://www.impulsespace.com/helios states Helios is compatible with Falcon 9, Falcon Heavy, Starship, Terran R, New Glenn, and Vulcan. They give payload masses for only Falcon 9 reusable and Terran R reusable, which suggests those are the vehicles they're guessing are the best fit. Looks like they can almost double Falcon 9 ASDS performance to high energy orbits, e.g. they give 6 tonnes to TLI whereas extrapolating NASA ELV figures gives ~3.55 tonnes for just Falcon.

2. They mention that F9 reusable with Helios can get 4 tonnes to GEO. For some reason my back of the envelope calculations suggest they should do better than this, around 5 tonnes to GEO, not sure what I'm missing. They appear to have rounded payloads to multiples of 0.5 tonnes, which could explain a portion of this discrepancy but not all. They apparently like 300 km LEO, which is 4231 m/s from GEO assuming 28.5 degree inclination. Assume F9 ASDS can get 17.5 tonnes to that orbit. Assume Helios is 13.5 tonnes dry mass so with a 4 tonne payload the staging occurs in LEO. Assume dry mass of 0.1*13.5 tonnes. One can then calculate the specific impulse as 4231 / ( ln ((4 + 13.5) / (4 + 0.1*13.5)) * 9.81) = 364 seconds. That dry mass and specific impulse are both a lot worse than I'd expect for staged combustion methalox, which their website says they're using. For example Raptor is also staged combustion methalox and is supposed to have 382 s specific impulse. Wikipedia says Starship has a dry/wet mass ratio around 100/1300, which is better than the 0.1 I assumed and Starship pays huge reuse penalties! So something I don't understand is hurting Helios's performance.

Offline chopsticks

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This could potentially be devastating for ULA. They love to talk about high energy, but if you have a reusable LV optimised for LEO (hard to make a reusable LV for high energy without refuelling) and cheap tugs, you basically take all of the argument out of ULA's talking points - the exception being an expendable high energy LV can deliver a payload to GEO quicker than a tug can dock. I don't know how necessary that would be though, that is, to get a sat to GEO asap. Obviously, depots will be needed to make this architecture work at low(er) cost.
If you have a super-cheap two-stage fully reusable superheavy that can put (say) 200 tonne into LEO, then its payload can be a 100-tonne expendable kick stage with a 100-tonne actual payload. I think this beats Vulcan Centaur, except for the minor fact that it does not exist. Think of it as a one-off "tug".

But this is completely off-topic for this thread. This thread is supposed to be about using a tug to allow one rideshare to hit multiple orbits to compete with multiple small launchers.
I mean sure, Impulse or someone else could make a huge kick stage for Starship if they wanted. They aren't though, at least not yet. What's your point? Various sizes of kick stages/OTVs can exist, not all sats/payloads are the same size.

Offline Tywin

1. https://www.impulsespace.com/helios states Helios is compatible with Falcon 9, Falcon Heavy, Starship, Terran R, New Glenn, and Vulcan. They give payload masses for only Falcon 9 reusable and Terran R reusable, which suggests those are the vehicles they're guessing are the best fit. Looks like they can almost double Falcon 9 ASDS performance to high energy orbits, e.g. they give 6 tonnes to TLI whereas extrapolating NASA ELV figures gives ~3.55 tonnes for just Falcon.

2. They mention that F9 reusable with Helios can get 4 tonnes to GEO. For some reason my back of the envelope calculations suggest they should do better than this, around 5 tonnes to GEO, not sure what I'm missing. They appear to have rounded payloads to multiples of 0.5 tonnes, which could explain a portion of this discrepancy but not all. They apparently like 300 km LEO, which is 4231 m/s from GEO assuming 28.5 degree inclination. Assume F9 ASDS can get 17.5 tonnes to that orbit. Assume Helios is 13.5 tonnes dry mass so with a 4 tonne payload the staging occurs in LEO. Assume dry mass of 0.1*13.5 tonnes. One can then calculate the specific impulse as 4231 / ( ln ((4 + 13.5) / (4 + 0.1*13.5)) * 9.81) = 364 seconds. That dry mass and specific impulse are both a lot worse than I'd expect for staged combustion methalox, which their website says they're using. For example Raptor is also staged combustion methalox and is supposed to have 382 s specific impulse. Wikipedia says Starship has a dry/wet mass ratio around 100/1300, which is better than the 0.1 I assumed and Starship pays huge reuse penalties! So something I don't understand is hurting Helios's performance.

I think so, Blue will use her Blue Ring for New Glenn...and Neutron have the Photon, but all the other is a good space tug...
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Offline sdsds

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I understand Helios to be Option #4: a one-time use kick-stage, provided by an intermediary between the payload and the launch vehicle. Perhaps somewhat like Agena and many comsat architectures it can/could also act as the spacecraft bus, making the payload design task easier?
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Offline XRZ.YZ

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