sevenperforce

Here's my take on today's mystery-shrouded military launch:

Experimental Imaging Satellite Russian military launches are notoriously hard to get info on, but I put it together as best as I could.

We won't really know until we get more specs, but chances are that with a lower TWR on the upper stage, the first stage will need to fly a more lofted trajectory. Lofted trajectories are good for recovery, but they are not great for abort. In an abort just before MECO-1, the capsule must separate from the upper stage and fire its abort motor. This places it in a very, very lofted trajectory, meaning it arcs far above the atmosphere and them comes in at a very steep angle. Steep angles are very high-gee, which could lead to serious injury or death for the occupants. This, for example, is why the Boeing Starliner needs to fly on the DEC (dual-engine Centaur) rather than the SEC.

Absolutely!

Second stage will be lighter, requiring lower thrust, but the much higher isp means more total impulse. Probably a small drop in TWR. This also means that the BE-4-powered first stage will have a smaller mass to lift to staging, which means bigger margins and better all-around performance. I am concerned about TWR and ascent profiles for when they try to man-rate this. Not only that, but they were already well along the path of developing a vacuum BE-3. Second stage will grow. As a result, they can now hit ALL specified national security orbits using only the two-stage reusable configuration. I don't think SpaceX can hit all orbits with full reuse.

Whoa! This is huge. Really really huge.

Wait, I thought this was what the US was supposed to test today. When was this? I just flew the simulated launch of the Soyuz 2-1v mission. Will get it up in a few minutes.

A touch late, but here's the mission post: I have three of these to do today. Phew!

GSAT 6A A little late, but no worry. The ISRO GSLV is a pretty interesting launch vehicle, given that it uses a solid core with liquid boosters that don't separate, and uses two additional serial stages above. I used some DLC parts in this for the first time.

I meant swap the stats; keep the models.

NRHO isn't too hard to hit. EM-2 is free-return; EUS places both Orion and the DSG propulsion module on a lunar free-return and then separates. The DSG (excuse me, LOP-G) propulsion module separates from Orion shortly after EUS jettison. I believe Orion will simply do the free-return while the DSG prop module does its own LOI at NRHO. It's EM-3 when you'll start to see Orion performing LOI to deliver modules to the LOP-G. Supposedly. FH can do EVERYTHING that SLS can do, up until the point that BFS is flying.

Falcon Heavy has a really ridiculously good mass fraction. My math is saying much more than 70 tonnes of propellant to LEO. TLI requires 2,730 m/s, which with an Isp of 345 seconds requires a propellant fraction of 55%. Stage mass, plus mating equipment, is about 4.5 tonnes. So, depending on the amount of propellant you have (which may depend on whether you use an expendable Falcon Heavy, a two-core-recovery Falcon Heavy, or an all-core-recovery Falcon Heavy), you can send varying payloads to TLI: 20 tonnes propellant: 11.8 tonnes payload 30 tonnes propellant: 20 tonnes payload 40 tonnes propellant: 28.2 tonnes payload 50 tonnes propellant: 36.4 tonnes payload 60 tonnes propellant: 44.6 tonnes payload 65 tonnes propellant: 48.7 tonnes payload 70 tonnes propellant: 52.8 tonnes payload 75 tonnes propellant: 56.9 tonnes payload 80 tonnes propellant: 61 tonnes payload 85 tonnes propellant: 65 tonnes payload 90 tonnes propellant: 69.1 tonnes payload 95 tonnes propellant: 73.2 tonnes payload (yes, I could have done that with a chart; so sue me) So it's not gonna happen. I think he was talking about ACES? No one needs to refuel FH.

My guess is as good as anyone's (okay, probably a lot better than 99% of the population, but still) -- but I am conjecturing that it's a combination of risk and benefit. Second reflights have not thus far been attempted, so they carry a high degree of risk. If a third flight was unsuccessful, it would really cast a lot of doubt on SpaceX's ability to make reuse financially viable. Much better to save refurb costs and wait for Block V to do the first multiple-reflight attempts.

Right. Assemble the DSG however you want in LEO, fully refuel it, and then launch a Falcon Heavy on an instantaneous intercept launch window with nothing but an international docking adapter on top. Load the upper stage with extra helium bottles, like the first FH launch. The Falcon family upper stage can provide pointing via cold gas thrusters even though it has no meaningful RCS to speak of, which is enough for the DSG to rendezvous and dock with the IDA. A couple of orbits later, the extra helium bottles repressurize the stage and the MVac does the TLI burn.

By my math, a naked Falcon Heavy upper stage can launch upwards of 65 tonnes to TLI.

Which, as best as I can tell, says: On March 28, the Progress-MS-07 cargo vehicle was undocked with the International Space Station. The re-entry and splashdown of uncombusted fragments in the Pacific Ocean is expected on April 26.

Falcon heavy stage is dead before it arrives in lunar orbit Which is why I suggested, above, that the DSG be assembled in LEO, boosted onto TLI by current launch vehicles (for example, Falcon Heavy upper stage launched empty), and then use its own engines for orbital insertion at its destination. Its engines are not powerful enough for trans-lunar injection but they can handle insertion.

I have a pretty good one set up as a subassembly but it's a bit bulky. And it's single-use.

The hexagonal golden sections can be constructed easily enough. Then it's a question of a stock hinge, landing legs for actuators, and Clampotron Jrs for locking into place. I may be able to get the secondary mirror to fold down similarly and ape the upper strut with an antenna. The sunshield will be well-nigh impossible.

Good point. I'm planning on doing the sounding rocket if I can. I don't know anything about this supersonic parachute and I'm having trouble figuring out the characteristics of the Terrier Mk70 SRB for the first stage.

Or a bloody Falcon Heavy upper stage.

That...may be slightly too complicated to build in KSP. I MIGHT be able to get an unlocking mechanism for the telescope hexagon panels.

Better option is to replace the Skiffs with Wolfhounds and the Wolfhound with a Skiff.

I have no less than three launches to do tomorrow. This will be interesting.

Or the DSG's own engines.