Author Topic: Discussion/Comparison of the new generation of American heavy lift launchers  (Read 18010 times)

Offline Paul451

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[...]

BFR's equivalent of "expendable" would be refuelling with 1, 2, 3, or 4 tugs. It shouldn't be hard to work out payload vs delta-v vs amount of refuelling. What delta-v numbers are you using for TLI/TMI/GTO?

Offline DreamyPickle

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Updated with BFR added, based on the attached chart from Elon's September 29, 2017 presentation.

Yes, BFR without refueling is pointless outside LEO. But it's explicitly designed to refuel in orbit so that should be included. Maybe also add distributed launch with ACES?

In theory BFR might be able to do more in expendable mode (like most other entries) but that's obviously silly and not going to happen. The design doesn't even include an option for detachable fairings.

Using a third stage inside the payload bay is also something that should be very seriously considered. The shuttle actually used this architecture and it would be the best way to launch space probes on BFR.

Offline Paul451

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Using a third stage inside the payload bay is also something that should be very seriously considered.

A single Raptor-vac based upper-stage with a total wet mass, including payload, maxing out the 150t to LEO, gives you 75 tonnes total mass to GTO. If the upper-stage is a lazy 10% dry mass¹, that gives you 60 tonnes to GTO.

Same stage gives 35t payload to 4km/s. 23t to 5km/s. 15t to 6km/s. Etc.


¹ In order to compete with the cost of just refuelling the BFS², any such expendable upper-stage would have to be cheaply built, trading mass for cost. Or you could spend more once for a reusable/refuellable tug.

² Musk's slides gave about 110 tonnes to GTO for a single refuelling.
« Last Edit: 10/07/2017 03:05 PM by Paul451 »

Offline envy887

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I estimate ~73,500 kg per launch to TLI with this architecture (662 tonnes counting lander and ascent stages and propellant over 9 launches). Six tankers stage at 200 km circular LEO, then the last two tankers stage at LEO+550 m/s.
« Last Edit: 10/09/2017 05:47 PM by envy887 »

Offline envy887

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I also estimate ~66,000 kg per launch to TMI with 6 LEO refueling launches (462 tonnes injected for 7 total launches, TMI is LEO+3900 m/s).

Offline envy887

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How I'd display it:

==============================================================
Vehicle          1st Flt   TransLunar   TransMars      GTO   
==============================================================
...
BFR                2022?         0 kg         0 kg  ~20,000 kg
BFR-R              2022?   ~73,500 kg   ~66,000 kg      ??? kg
...
==============================================================
"X" Denotes Expendable Version
"R" Denotes LEO Refueling, per launch basis
« Last Edit: 10/09/2017 05:46 PM by envy887 »

Offline envy887

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Also; the expended core but the two boosters landing downrange on the barges.

There are many theoretical options, but I think Ed wants to concentrate on the practical and more likely options.

With a 2nd East Coast ASDS under construction, this is now a practical and likely option.

Updated with BFR added, based on the attached chart from Elon's September 29, 2017 presentation.

==============================================================
Vehicle          1st Flt   TransLunar   TransMars      GTO   
==============================================================
Falcon 9 Blk 5     2017?    ~3,000 kg?   ~2,500 kg?   5,500 kg
Falcon 9 Blk 5-X   2017?    ~5,500 kg     4,020 kg    8,300 kg
Falcon Heavy       2018?    ~5,500 kg    ~4,900 kg    8,000 kg
Falcon Heavy-X     2018?   ~20,500 kg    16,800 kg   26,700 kg
SLS Blk 1          2019?    24,500 kg    19,500 kg      N/A
Vulcan Centaur 56x 2019?    ~8,300 kg    ~6,200 kg   10,200 kg
New Glenn 2 Stg    2020?    ~7,500 kg?   ~3,000 kg?  13,000 kg
NGL-5xx            2021?    ~6,000 kg    ~4,700 kg    8,500 kg
SLS Blk 1B         2021?    39,000 kg    32,000 kg      N/A
BFR                2022?         0 kg         0 kg  ~20,000 kg
Vulcan ACES 56x    2023?    14,000 kg    10,500 kg   17,200 kg
NGL-5xx-XL         2023?   ~10,300 kg    ~8,200 kg?  14,700 kg
New Glenn 3 Stg    2025?   ~25,000 kg?  ~20,000 kg? ~30,000 kg?
SLS Blk 2          2028?   >45,000 kg   >37,600 kg      N/A
==============================================================
"X" Denotes Expendable Version

Updated 10-06-17{/pre]

 - Ed Kyle

You can take the question mark off the FH date.

FH center expended, boosters ASDS would be a good addition, as we now have well-sourced capability and price estimates (~24,000 kg to GTO, 18,000 kg to TLI, and 15,000 kg to TMI for ~$95M).

Prices in general would be a good addition to this table, since they are just as relevant in any rocket compassion as performance is.

Hopefully the Block 5 data shows up on NASA LSP site soon and we can get better figures.
« Last Edit: 02/13/2018 02:36 AM by envy887 »

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