sevenperforce

As I am sure you are aware, FH+D2 to Mars was upstaged by an acceleration of the evolved Raptor-based launch vehicle development. Cancelling one mission in preference for another one isn't a failed promise; it's progress.

Ever since AMOS-6, they never static-fire with the payload integrated. The only exceptions have been Falcon Heavy's first test flight (when they had Elon's Roadster on top as a dummy payload) and the first launch of Crew Dragon (when Dragon 2 had armed LES).

So weird to see it without its fairing! Used to seeing F9 not but FH. Nice to see the "tuxedo" look on the stages.

Hmm, based on this post the J-2X would have only had a single-point downthrottle at 84%.

I will evaluate gee-loading on the docking clamps in comparison to the planned Constellation architecture. Orion has the same docking clamps as in the planned EOR-LOR with Orion + Altair + EDS, and the Ares V EDS would have used either one or two J-2X engines with a max thrust of 1,307 kN each. They could downthrottle as low as 52% based on this article and so I will use a minimum thrust of 1,359 kN at the termination of the TLI burn for maximum gee-loading on the docking clamp in the Constellation architecture. I anticipate gee-loading for the Falcon+Dragon+Orion stack to be a little higher, since Altair massed SO much, but probably no more than a factor of 2. Hmm. I may do this. If I write a simple whitepaper and post it publicly online as an open letter to Bridenstine et al, will you guys help me spread it?

Raptor has now flown under its own power. Next thing you'll be saying that since SSMEs have flown before, SLS has technically already flown.

It moved under its own power. It counts. They can handle it. Same docking system intended for Constellation.

Steel, not aluminum. Also. it flew tonight.

Raptor is officially a flight-tested engine. Welcome to the future.

**presses F to pay respects** We gon' rock this club We gon' go all night We gon' light it up Like it's dynamite Ignition over a naked pad has such a lovely futuristic blast pattern.

EFT-1 had a boilerplate ESM. Same mass, but very little dV. Easily. Even if they had to burn a little of the ESM to complete the TLI (which I am pretty confident they wouldn't need to do), it would still work. Pod bay doors?

Decided to try and validate this with some cold, hard numbers. The DCSS on EFT-1 put Orion into a funky suborbital trajectory with a high apogee but a perigee below the surface. If it has reached the same apogee from a standard 200 km reference orbit, it would have been 1088 m/s past LEO. I'll lower it to 950 km/s past LEO to accommodate that. Dragon 2 masses 10.9 tonnes with props and no cargo or crew. We know FHB5e can deliver 26,700 kg to GTO, meaning it can definitely deliver Dragon 2 to GTO plus 15.8 tonnes of residuals. Estimating FHUS at 4.5 tonnes, this means it departs its 200-km parking orbit with 45.3 tonnes of residuals. Matching the same orbit as EFT-1 (assuming this is 950 m/s past LEO) would leave it with 29.9 tonnes of residuals. There's some additional conservatism here. Dragon 2 will burn off a fair amount of its own props in the rendezvous and docking with Orion, but I'll pretend it doesn't, for conservatism. At docking, the stack masses 10.9 tonnes for Dragon 2, 4.5 tonnes for FHUS dry mass, 29.9 tonnes of residuals, and 25.8 tonnes for Orion+ESM, for a total of 71.1 tonnes in eccentric orbit. The FHUS's 29.9 tonnes of residuals will push the stack an additional 1860 m/s for a total of 2,810 m/s past LEO. TLI is 2,730 m/s past LEO. So the Falcon Heavy, launched to the same eccentric earth orbit as EFT-1, can push both Dragon 2 and Orion+ESM to TLI with 80 m/s of dV to spare. The math checks out.

Starship could be used as a 1.5STO by adding a couple of extra engines and mounting drop tanks in this configuration (or side-slung). The name is almost the same already. I wonder how compact I can make fold-down locking wings....

Jupiter DIRECT would have worked too.

Simply having an abort tower makes it better than 1:12.

The more you know.....

Yeah, it should work. Let me throw together a diagram. Far left shows D2 still attached to FUS. Center shows a nominal port thruster firing. While free-flying, this would go through the CoM, but with the FUS attached it will induce rotation around the much lower CoM, producing yaw to starboard. To counter that, D2 would need to also fire a port-aft and a starboard-fore thruster; this will induce a yaw to port within the capsule, counteracting the rotation around the stack CoM. If that was the case then FH wouldn't even need to launch dragon; it could simply launch an empty FUS and it could use its cold-gas thrusters to hold orientation. However, Orion's autonomous docking software is not yet operational, so it would need to passively hold orientation while Dragon performed the actual approach and soft docking. Dragon 2's software is fully operational. It is capable of carrying externally-manifested payloads (up to at least 3.5 tonnes and potentially as much as 6 tonnes) in the trunk, which means it is already capable of compensating for a lower or higher center of mass. Enabling it to mate with FUS attached could actually be as simple as updating the CoM variable to allow a much lower CoM.

Dragon 2 has 18 Draco thrusters. It can translate sideways while mated to the FHUS by using off-axis thrusters to compensate for pitch control. Software problem. Would use more props than nominal docking, but again, totally doable.

I love it!

Here's what could actually work, right now, with no modifications to anything other than software: Repeat EFT-1, leaving Orion and its fully-fueled ESM in an elliptical earth orbit. Launch a reused Dragon 2 on FHB5e into the same elliptical earth orbit; do not separate Dragon 2 from FHUS. Use Dragon 2's autonomous docking capabilities to mate Orion and Dragon 2. Software updates required for Dragon 2 to compensate for the added mass and altered CoM with the FHUS still attached. Use residuals in FHUS to push Crew Dragon + Orion + ESM into TLI. Orion and Crew Dragon separate after TLI. FHUS is ejected into heliocentric orbit; Crew Dragon completes a mid-course correction and performs a free-return; Orion performs DRO or NRHO injection for EM-1. Crew Dragon tests heat shield on entry from cislunar space. Orion performs cislunar mission, then burns EOI for completion. No new vehicles, no new adapters, nothing. FH has same US configuration as in the Tesla test flight (modifications for extended restart).

The EUS is the exploration upper stage for SLS Block 1B which is intended to push both Orion+SM and any comanifested payload to TLI. The EUS is not Orion's SM. Orion's SM is smaller than Orion, but Orion is still just over 5 meters. The internal envelope of a FH fairing is 4.7 meters. You cannot fit Orion on FH without a custom fairing. If Orion+SM was launched on FH without ICPS, you could create a custom fairing that is the same diameter as the current version but truncates at the top of the service module, just as was done with EFT-1: This is possible because the SM will fit within the 4.7-meter internal envelope of the existing Falcon family fairing. However, the ICPS (which is literally a DCSS from the Delta IV family) is 5.2 meters and would not be able to fit inside this envelope. Either Falcon Heavy would need a new 5.5-meter fairing to wrap the ICPS + SM + Orion, or the entire upper stack from ET-1 would have to be dropped on top of a custom truncated 5-meter fairing stretching from the top of FHS2 to the base of the DCSS/ICPS's hydrogen tank. Another significant issue raised by Bridenstine is the integration and erection of the FH in either configuration. FH is horizontally-integrated, rolled to the pad, erected, and then prop-loaded. However, Orion and the SM were intended to be vertically-integrated. Not only would that need to change, but they would also have to contend with a much more top-heavy FH, meaning the TEL might struggle to get it vertical. I've seen detanking flares but no test fires yet...where are you getting this?

I think you mean boom boom boom boom boom boom boom boom boom Well, as fond as I am of dropping nukes on a bare pad, I have a deep appreciation for the Orion Saturn V concept... Oh what a brilliant idea. "I really like this whole 'ride across the stars on pulses of thermonuclear fire' concept, but how do we make it more exciting?" VentureStar and Starclipper are two favorites, particularly the latter:

It's also easy to forget just how big a rocket Falcon Heavy actually is. FHB5 carries 154% as much liquid propellant as the core of the SLS and boasts 251% as much thrust.

One word. Orion. The real one.

Does anyone have any reasonable idea of how much dV is carried by Starliner? It can't be much.