Alan Boyle has more details on Blue Origin's plans.

A hundred kilometers, once a week, with three or more passengers. That's at least a hundred fifty new "astronauts" per year. How big will their fleet be?

Their choice of propellants is interesting--peroxide and kerosene. I wonder what the strength of their peroxide is, and where they're getting it?

Rand,

It's kind of surprising they're going after Peroxide/Kerosene. The performance is decent, but for the goals they're shooting for (one shot per week, 100km, 3+ people), I really don't see any reason why not to use LOX instead. But I may just be biased by what we're doing at MSS.

If they are doing peroxide/kero, they're going to need a fairly high concentration (probably somewhere above 80-85%). My guess would be that they're either going to pay someone to setup a peroxide distillation system, setup their own distillation system, or maybe Jeff might be considered just deep-pocketed enough to FMC that they'll sell directly to him. Personally I'm hoping the former (which would be similar to what Beal did), because that might allow other ameteur groups to get access to the stuff more easily.

~Jon

Anyone else surprised that they're doing VTVL? It seems that would be riskier from a piloting and engineering standpoint that a horizontal landing mode, since it seems to be you'd have to be able to throttle your engine pretty minutely during descent, and couldn't really survive one of the landing struts going out. (Then again, anyone know how fast SS1 lands? At high enough speeds, you probably couldn't survive blowing a tire either)

IANAAE (I am not an aerospace engineer), so does anyone reading here have any insight as to why they might have picked a VTVL profile?

The peroxide concentration would have to be pretty high to work. Perhaps he bought Beale's production setup. The big advantage of peroxide and kerosene is that they're room temperature propellants. This simplifies propellant handling and storage somewhat, but high concentration peroxide can be pretty dangerous stuff. Any contamination can be catestrophic.

VTVL has the advantage of simplicity. Your vehicle structure can be relatively simple and light compared to winged or lifting body designs. It's doubtful they'll use turbopumps for the engine. More likely, they'll use pressurized fuel tanks, meaning engine throttling can be handled by controlling the propellant flow valves (like they did on the Apollo Lunar Modules). Of course, they'll have to carry enough propellant to allow for landing and make sure that a single landing strut failure won't cause the vehicle to topple over (benefits of lessons learned from the DC-X).

Jeff,

The reality of the HTHL vs VTVL comparison is that both have strengths, both have weaknesses, and like most things in engineering you have to make a tradeoff. Throttleability issues aren't anywhere near as bad as you might think on first blush. For a Peroxide/Kero engine, throttleability is pretty easy since it is a hot-gas/liquid mixing/combustion process. IIRC Armadillo had some good results with Peroxide/Kero before availability issues forced them down other paths. I believe there have been several other options discussed in open literature about ways around requiring deep throttling. Do a google search on VTVL throttling, and you'll probably find a few suggestions from Henry Spencer or others.

As for landing strut survivability....I don't really see that as being any more or less survivable than a landing gear failure on an HTHL vehicle. Ie it will likely damage the vehicle a bit, but isn't likely to do much harm to passengers who are firmly strapped into the vehicle.

The company I'm with (Masten Space Systems) is also developing a VTVL reusable vehicle, and we've been through the tradeoffs and discussions. Ours is quite a bit smaller than what Bezos is likely doing, uses LOX/IPA instead of Peroxide/Kero, and is initially intended for launching suborbital science payloads, but the actual flight mode is probably pretty similar. Basically, we think we can make it work, and we thing we can make it just as reliable as a comparable HTHL system--or we wouldn't be doing VTVL. And there are some definite perks to doing in the way we're doing it. Time will definitely tell on these things, the next few years should be really interesting for suborbital RLVs of both the VTVL and HTHL type.

~Jon

Thanks for the info, Jon. And good luck with your company's project.