Soft landings

LANTR seems to stop short of landing a craft upon the Martian surface. As to that L1 Kevlar rope, as it is under construction it might leave a megameter or two over the landing spot. Bouncing cargo onto bare regolith is going to kick up some dust. Launching off again will kick up still more, especially if they use the Al-LOX mix.

A week ago Space Startup News pointed to xARC, on the southwest edge of the Texas Triangle, concerning Lunar mission architecture. They were going to drop off some 'bots to roam the regolith and cook up hexagonal bricks, to ensure dust-free landing pads, roads, other pavements. (Lunar Forge is on that tech.) Also supplied would be berms to keep dust from drifting back in, from all the industry hopefully happening around the site.

Meanwhile in June, Anderson, Saxena, Metzger [ht Toughsf 31 August] came up with another idea. The Solar-System has already built some berms for us, in the form of small craters. Land craft with the fragile cargo in one of those. Schlep cargo over rim with Lunar Terrain Vehicle. Assemble base around crater (some material here could have been dropped less-gently in other missions).

Zubrin has long noted is that bricks are good for pushing down, but not for pushing out. We are here talking about the base camp, even its airless robot-only stage. It might be a trick to find a suitable berm-crater reasonably close to a human-friendly environment, like a lava cave.

LANTR

Whilst we await Firestar's nuclear afterburner, Borowski et al. a decade ago had proposed a chemical one. The subtext, best I gather, was that old solid-core NERVA for all its 900s I_sp wasn't all that great for thrust. Most Mars missions assume NERVAlike NΘP. Or big punches to orbital trajectories, like The Martian to Hohmann.

Borowski's crew was pondering a high-thrust solution as may ignore much I_sp and Earth won't care what is burnt near us. This has a use-case in delta-V punches: a mission to the Lunar poles. I'll bite; even that spaceline only got to equatorial Sinus Medii.

The promise is to achieve liquid-core-temp exhaust whilst still keeping the (fissile) heat-source, solid. That'd be a safer reactor in HEO, might even allow lower-grade fuel. In 2024 the plasma-core was still SDI scy-fy (and in 2026; also none of us knew or know what Howe is doing).

NERVA, it happens, assumes hydrogen for propellant. As the Hindenburg passengers can tell you, it reacts with oxygen. (This blog takes no sides on the cause of that one's initial blowup.) The paper suggests to bring along liquid oxygen - LOX - with that superheated hydrogen. The LOX is introduced after the burn which raises the exhaust velocity. This is thereby an "LANTR". Oxygen is cheap on our moon, maybe the only cheap volatile.

As to why to do this: that is because the N part of NΘP is a nuclear reaction, and not - like Orion - a bomb. As a reaction, it is supposed to run for longer. NERVA hasn't been tested for many hours in, what amounts, a thermos the size of the Universe. Earth might not want a reaction running long in our shared well.

For short bursts of heat one might even swap those nucular roggets for enthalpy. Which segues...

The antiquity of Liber Antiquitatum Biblicarum

If you had read (ye) "Old(e) Testament Pseudepigrapha": one of the texts herein was a pseud' on Philo. Of course Philo had nothing to do with the Antiquitatum Biblicarum. Western Christians, who copied and have edited this work, have rated it a "Pharisaic" document: close to Josephus' halakha against, say, Judith's (or anything else of the pre-Revolt Diaspora). Zeev Safrai posted an essay on "LAB" in 2018. Safrai puts this in the Jamnia / Javneh era after 70 CE, when the priests didn't matter.

As far as I know a post-Qumran date wouldn't have ruffled feathers at any point since the late 19th century relieved it from Philo. LAB was composed in Hebrew but Qumran shows no awareness of it (we'd be looking to Jubilees, which relation is reversed). It hasn't been picked up by Septuagintal literature the way Judith, say, was picked up in the Greek Esther. As noted Philo didn't know it. It is antiSamaritan, inasmuch as the old shrines at Gerizim / Shechem are condemned. The mutual relationships with 2 Baruch and 4 Ezra / 2 Esdras are famous.

Safrai dates LAB rather after Bar Kochba. It seems of interest LAB sides with Shammai on whether children should fast, where the Mishnah gives to Hillel the last word against Shammai. LAB also retains Jubilees' interest in maintaining the names of Israel's matriarchs, although I cannot call that "feminist" (this reflects a tradition of matrilinealism). These intra-Jewish disputes seem early to me. So far I admit this is a matter of taste.

I don't see where Safrai's essay has raised skub in the past eight years. So... I'll do it:

Within the earlier decades, came the Judaeans' Tumult in Cyrene, Cyprus, and Alexandria. Vridar, when he was poasting, deemed this revolt an important event. LAB - as Safrai knows - argues for the general eretz-Israel as holy and under G-d's protection. Perhaps this nods to a time when Jews were persecuted everywhere but in the Judaea proper, where peace maintained. I don't think that Jews could honestly say this after Bar Kochba and Hadrian.