sevenperforce

Liftoff! Damn it comes off the pad fast.

Do they kick Centaur out into a graveyard orbit after, or deorbit?

I cloned this mission here: In the webcast, it said there will be three burns of the Centaur. Is this direct-to-GEO? My mission clone went to KTO and used the payload to circularize.

GOES-S, United Launch Alliance. First launch of the campaign!

Stock. Part of the challenge, for me, is replicating each LV using only the parts in stock plus Tweakscale. I have a fully-stock Dragon 2 + Falcon 9 that doesn't even require Tweakscale, but I will definitely be using Tweakscale for anything with SRBs because the stock ones are so small. Plus, playing stock lets me sandbag and spend extra dry mass getting each stage perfect.

So, I had an idea. Why not create a save in which I could replicate every single real-world launch, on the day it happens? The only mod I'll be using is Tweakscale. As I play, I'll be saving each part I build as a subassembly, so I can quickly replicate any launch vehicle in any configuration. Thus, most of the building time will be payload-oriented. Running list of launches: March 1, 2018: GOES-S, launched on a ULA Atlas V in 541 configuration. March 5, 2018: Hispasat-30W6, launched on an expendable Falcon 9. March 9, 2018: O3b, launched on a Soyuz-FG. ISS (not launched; just built in the SPH and dropped into orbit). March 21, 2018: ISS Expedition 56, launched on Soyuz. March 23, 2018: ISS Expedition 56 Rendezvous & Docking. March 29, 2018: GSAT 6A, launched on ISRO's GSLV Mk2. March 29, 2018: Russian Experimental Imaging Satellite, launched on Soyuz 2-1v. March 29, 2018: Chinese Beidou-3/4, launched on Long March 3B. March 30, 2018: Iridium-NEXT 5, launched on SpaceX Falcon 9. April 2, 2018: CRS-14, COTS with Dragon 1 launched on SpaceX Falcon 9. April 4, 2018: CRS-14 Rendezvous & Berthing. April 5, 2018: DSN-1/Superbird-8 + HYLAS-4, launched on Ariane 5 ECA. April 11, 2018: IRNSS-1I, launched on ISRO's PSLV-XL. April 14, 2018: AFSPC-11, launched on ULA's Atlas V in 551 configuration. April 18, 2018: Blagovest-12L, launched on Proton-M. April 18, 2018: TESS, launched on the last SpaceX Falcon 9 Block 4. April 25, 2018: Sentinel 3B, launched on Rockot. May 3, 2018: Apstar-6A, launched on Long March 3B. May 5, 2018: InSight, launched on Atlas V 401. May 5, 2018: CRS-14 Return.

The Soyuz re-entry capsule is almost completely spherical; there is a very very slight amount of conic extension to the truncated sphere, allowing a tiny amount of lift, but entry is far closer to ballistic than typical US entry capsules. From Wikipedia:

Only very transiently.

Russian capsules use a truncated sphere as their re-entry vehicles because this is the most efficient use of space. However, truncated spheres cannot be oriented in such a way as to produce list, and therefore must enter ballistically, which is rather hard on the occupants. US entry vehicles have been conical, because a conical capsule (while not as efficient in terms of space used or launch vehicle size) can be steered to produce lift and adjust the rate of descent. Steering can also direct them more accurately to a particular point. Remember that it is compression, not friction, which generates 99% of heat on re-entry. What we identify as temperature is based on the average speed of the individual molecules in the air around us. This is actually a pretty steady clip; the average speed of an oxygen molecule in the air around you right now is about 450 m/s. Each time an air molecule hits your skin, there's an exchange of kinetic energy; if you're warmer than your surroundings, the air molecule gains energy and so you feel cool; if you're cooler than your surroundings, the air molecule loses energy and you feel warm. High in the atmosphere, air molecules are moving much faster since they receive more direct heat from the sun, but molecules are few and far between and so there is less opportunity for thermal transfer, which is what allows water vapor to condense into clouds or even ice. When a re-entry capsule slams into the atmosphere, air molecules are pressed together faster than they can flow around the heat shield. This compression causes the molecules to collide with each other much more frequently, building up kinetic energy which eventually becomes so great that the molecules ionize and turn to plasma. The reason for the blunt-body shape of a capsule is not only to expose as much surface to the atmosphere as possible, making drag maximum, but to shape the flow of plasma such that most of the heat flows out around the capsule rather than being transferred to the heat shield. Most of the heat taken by the heat shield is actually due to radiative heating from the plasma (ionized air releasing photons which strike the heat shield) rather than thermal transfer.

In the interest of creating a proper VTOL similar to the F-35C or Harrier, I've been trying to work on creating a powered, locking hinge assembly that would allow an engine to be undocked, rotated 90 degrees, and redocked, reversibly and repeatedly, using only action groups. I've worked on it for quite a while and I've never been able to get it perfect. Here's the closest I've come: So the challenge is this: create a rotating assembly, in stock, that uses action groups to complete a powered 90-degree rotation that can be repeated indefinitely. Level 1: Create and demonstrate only the assembly. Level 2. Demonstrate that engines can be affixed to your assembly. Level 3. Build a VTOL aircraft around your assembly and demonstrate liftoff, hovering, transition, translation, and vertical landing. Level 4. Build a VTOL SSTO around your assembly and demonstrate liftoff, hovering, transition, ascent, orbit, deorbit, re-entry, and vertical landing. Lowest-mass hinge assembly wins.

I got several faster ascents but they were all escape trajectories as well.

No. The LV-N has no thrust in Eve's atmosphere.

That was what they did initially, but now that they're using 1-3-1 burns on RTLS, this may no longer be the case. The booster comes in with an AOA and flies an odd trajectory; despite numerous analyses over at NSF, no one is quite sure.

I'm inclined to agree. SpaceX will only RTLS when they have plenty of margin to do so, and any engine start problems would likely be detected during either the boostback or the entry burn, giving the stage plenty of time to redirect and ditch in the ocean. With additional TEA-TEB due to lessons learned from the FH core splashdown, I don't really see it as likely.

Cryptocurrency is in the early stages of existence. There's definitely a need for a digitally-transferable independent currency, and to that end altcoins have an intrinsic value, but the way they are being traded right now is pretty rotten. Altcoin mining is not unlike mining any other rare item; you're simultaneously creating wealth and watering down the market. It's a little like coin scams. My parents got roped in by Royal Bank, a gold-coin-trading MLM scheme back in the early 90s which artificially inflated the value of minted gold coins, and once that scheme collapsed the gold coins lost their inflated value, but gold is still worth something. Cryptocurrency inflation precipitated by extremely enthusiastic trading may collapse spectacularly or may deflate slowly, but in either case the underlying commodity still has some intrinsic value. Another potential value in offworld habitation is a tax or data haven. But typically that wouldn't require human operators.

What do we think the chances are that SpaceX will ever have a Falcon 9 RTLS landing failure after entry burn shutdown?

With Atlas V in the 541 configuration (flown five times previously, including Curiosity), liftoff thrust is 10.58MN, 12% higher than Delta IV Heavy and 39% higher than Falcon 9 Block 4. Of course, even in the 551 configuration, it's only 54% the liftoff thrust of Falcon Heavy.

Correct.

The chances of any interactions are extremely low, but in the unlikely event that the F9 had some weird chain-reaction engine failure and the AFTS took a few moments to catch it, the chance of a ruptured COPV exploding out and hitting the other pad are probably higher than the chances of debris from a failed RTLS landing getting anywhere near the other pad.

SpaceX launches are more of a risk to the neighboring pad on liftoff than on RTLS.

"Shoo" is putting it mildly.

Pilot reuse optional, apparently.

Good grief what a death trap. Still, he was the first person in history to take off vertically under rocket power, so that's something. DO IT DO IT DO IT

The Grumman concept: Vertical takeoff on rockets; horizontal landing on jets. The orbiter carries two crossfed drop tanks discarded at 300 m/s under orbital insertion. On the subject of rocketplanes, let's not forget the German interceptors which launched under hypergolic rocket power and then had to glide back. They were too fast to actually shoot at Allied bombers, so they came with vertically-oriented rockets in the wings. The rockets were activated using a photosensor, so the pilot merely had to arm a pair of rockets, steer underneath an Allied bomber, and the shadow of the bomber above would trigger the rockets and fire.

Horizontal takeoff under jet propulsion and relatively modest climb, then fire up the rockets and pitch up hard. Both vehicles use jet engines to RTLS and land on a runway. The shuttle was supposed to carry (among other things) drop-in fuel tanks for a reusable moon transfer tug. That's the point -- you can't use your main engines for braking unless you can reliably air-start them while flying tail-first. Supersonic retropropulsion was completely pioneered by SpaceX.