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Comment: Re:Commercial Payload Companies... There are... (Score 1) 60

by jrst (#33432248) Attached to: NASA Buying Private Companies' Suborbital Rocket Flights

Take a look at Surrey Satellite Technology http://www.sstl.co.uk./ They have a selection of standard platforms and payloads (or BYO payload). Their standard platforms/payloads focus is EO and Comm/Nav, but not limited to those.

However, if you go to any of the majors, they'll also start with a standard bus; they just don't market that part heavily because the value/money is elsewhere. I doubt there are very many commercial sats/payloads built on a one-off/custom bus these days. Those that are most likely are relatively high volume (e.g., GPS, Iridium, etc.). (Hughes started doing that long ago for comm sats).

Comment: It's uglier than you can imagine. (Score 5, Informative) 159

by jrst (#33178820) Attached to: New Spacecraft Set For Dangerous Jupiter Trip

It's uglier than you can imagine.

IIRC (sorry, it was long ago)... on the Pioneer 10//F 11/G missions Van Allen spec'd the Geiger Tube Telescope for an order-of-magnitude more than expected, and we pegged them. Pioneer suffered significantly--never regained full range on one channel of the IPP (Imaging Photopolarimeter--that thing that made the pretty pictures possible).

We nearly lost the spacecraft due to some spurious crap/commands during periapsis on Pioneer 10/F. Try dealing with an idiot-savant-brain-damaged-two-year-old throwing a tantrum with ~90-minute round-trip light time at 256-1024bps. It's ugly.

The running joke was... If you want to be absolutely certain a spacecraft is sterile, just make a flyby of Jupiter. Jupiter's belts are not to be taken lightly. A seriously understated quote from one post-mission presentation "Closest approach: It’s hot in there!"

It's not just hot, it's a red-hot-poker enema in your electronic guts. That Pioneer 10/11 F/G--the epitome of cheap deep-space exploration--survived those encounters and lived to tell--and did so for many more years still amazes me.

It is a testament to what we can do, and what deep-space exploration is all about. (So allow me a bit of hubris: Suck eggs Voyager... you had a much bigger budget, you got the press, you got your name in a Star Trek movie, but we were there first. Nah nah nah.)

Comment: Re:The space WHAT? (Score 5, Informative) 297

by jrst (#29907509) Attached to: Russia Develops Spaceship With Nuclear Engine

Hogwash. The US may has been dicking around, but others haven't. Your comment typifies everything wrong with the typical US attitude to space exploration.

The Russians were in space almost continuously from 1971 onwards--from Salyut, through to Mir and then the ISS--running manned missions and supply flights almost continuously until the present. The only pause in the Russian program was a couple years between the time Mir came down and the first ISS module was put up (again, the Russians).

From 1971-present the US couldn't put a man in space for years over several periods: after Skylab; after Challenger; after Columbia. Meanwhile, the Russians continued to grind along, slowly but surely, providing both manned and unmanned supply flights. Those Progress and Soyuz flights that helped keep the ISS alive? Those were from Russia, using proficiences they developed during the 20+ years *regularly* servicing Salyut and Mir and maintaining a manned presence in space.

Check the total time in orbit for the Salyut and Mir, days inhabited, and the number of missions--it's pretty damned impressive. And that was long before the ISS or the Shuttle.

They weren't "dicking around". They were doing serious science on long-term manned missions, and what it takes to sustain an effort, especially from an operational/practical perspective. It's no accident that a lot of the practical ISS LS systems are based on what the Russians learned and developed. NASA has refined some of those systems, but a lot of the basic tech (air revitalization, toilets, etc.) came from the Russian program.

This isn't a "race", at least if you're interested in more than flags and boots. It's learning. It's exploration not just of places, but of systems. It's engineering. It's figuring out how to make people and machinery work in environments that are hostile and for which many effects are little understood. You do that by trying, correcting, and trying again. That takes time and a sustained effort.

Comment: Good for them (Score 1) 297

by jrst (#29906723) Attached to: Russia Develops Spaceship With Nuclear Engine

Good for them. Nothing really new here, but someone has to make it clear that we aren't going anywhere much beyond the atmosphere on a sustained basis without nuclear power in space.

That includes space guns, space elevators, and whatnot--you need a tugs ("orbital transfer vehicles") to collect all those cheap/dumb parcels and deliver them to where they're needed. Or you use larger/smarter and more expensive vehicles with automonous maneuvering systems (which is what we do today), and which is why (*cough*) $5-10K/Kg-to-LEO turn into $20-80K/Kg of net payload (usable payload minus delivery vehicle structure, guidance, propellant, etc.

Advanced propulsion (e.g., hall-effect/ion/vasimir/thermal) with solar electric power might be OK for slow orbital or cislunar tugs, but are limited due to mass penalties and array degradation. Such systems need power to get anywhere in a reasonable amount of time, and the more power (in general) the better. Fusion? Maybe someday.

If we in the West can't manage to swallow our aversion to nuclear power in space (real power, not RTG's), then we will cede space to those who will, whether Russia, China, India or whoever. Maybe when they esablish a sustainable LEO and cislunar system (or a Mars effort) using nukes people will wake up (Sputnick redux), but I won't hold my breath.

Pick your poision... Very limited and occassional manned exploration using chemical propulsion, or a long term and sustainable effort using nuclear power/propulsion. I'd prefer the latter.

Good luck, and more power to them.

Comment: Not nearly enough (Score 3, Insightful) 384

by jrst (#29714863) Attached to: Gigantic Air Gun To Blast Cargo Into Orbit

1. In round numbers:
. ~9.5 km/sec to LEO (given, approximate)
. ~6.0 km/sec from gas gun (FTA)
. ~0.5 km/sec atmospheric drag (FTA)
= ~4.0 km/sec needed from projectile rocket
. 350s ISP for projectile rocket (assumed, optimistic)
= 0.69 propellant fraction
. 450Kg projectile (FTA)
= 310Kg projectile rocket propellant
= 140Kg projectile non-propellant
. ???Kg projectile structure, motor, etc.
= ???Kg net cargo to LEO (in any case, 140Kg)

2. Assuming you want to rondezvous with something in an established orbit (e.g., the ISS), any significant orbital maneuvering is out of the question; in paticular an orbital plane change--whether by the projectile or the target--as it's too expensive.

That limits the number of launch windows. You can't simply launch projectiles into orbit as fast as the gun can fire, otherwise you'll end up with them scattered in various orbits that you have to chase down (again, very expensive).

E.g., there are nominally 2 launch windows/day for Shuttle flights from KSC to the ISS. (Due to various rules, in practice it's limited to 1/day, but we'll ignore that.)

3. Even with optimal launch parameters, orbital rondezvous is still non-trivial, and one reason why even unmanned ISS resuplly vehicles are much more than simply a dumb ballistic container, and have, e.g., OMS and RCS motors, propellant and the weight/complexity/cost penalties that come with them.

Which is why larger, more infrequent and expensive missions will remain the norm for the foreseeable future--with or without a space gun or its ilk.

4. In short, we need an orbital infrastructure that can handle smaller/dumber vehicles. That doesn't exist, and few if any of these proposals account for it. With, e.g., a group of ion/electric tugs it may make more sense. That is, something that can cost-effectively collect those smaller/dumber vehicles and bring them to where they're needed.

Just go with the flow control, roll with the crunches, and, when you get a prompt, type like hell.

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