Closer to 5%, but still pretty much irrelevant.Analyst
but still pretty much irrelevant.
The ISS orbit inclination (51.6°) may not really be a problem.
In a fantasy world where you can add more solar power, you could use VASIMR to change your inclination if you wanted to (although it'd take a LONG time). How much delta-V does it take to change the ISS's orbit? How much delta-V is burned every year by atmospheric drag? Admittedly, this is probably just a fiction, since the power budget on ISS is pretty thin to be using much of it for the VASIMR, as far as I know. ...not to mention that the Russians wouldn't let you do it, since the station is about half theirs.
Aren't the Russians negotiating to use Kourou?
Quotebut still pretty much irrelevant.Why ?
Quote from: Archibald on 10/20/2009 04:57 pmQuotebut still pretty much irrelevant.Why ? Because 5% are pretty much irrelevant. You have a big, ~$60 to 100 billion asset in orbit. You don't built a new one just because of 5%. This is almost in the noise, a little bit above your performance margin. Analyst
Quote from: Analyst on 10/20/2009 08:48 pmQuote from: Archibald on 10/20/2009 04:57 pmQuotebut still pretty much irrelevant.Why ? Because 5% are pretty much irrelevant. You have a big, ~$60 to 100 billion asset in orbit. You don't built a new one just because of 5%. This is almost in the noise, a little bit above your performance margin. AnalystGood point! We need more in-space resources like the ISS that we can reuse. Assuming you could get everyone to agree with it politically (and bureaucratically... I'm looking at you, JSC), could you dock a large exploration craft with empty hypergolic fuel tanks at ISS, transfer crew to the craft, refuel it propellant and water with Progresses (or similar craft like ATV) docking to the other end of the exploration craft, test all the subsystems, and launch? Then, after the trip, could you dock again with the station and have the crew transfer to another craft capable of reentry, like a Soyuz or a Dragon capsule or something?
One or two benefits: after commercial crew to the ISS is going, any launch vehicle can be used for exploration hardware without worrying about man-rating requirements. Any parts of "lifeboat-only Orion" related to the launch escape system or even astronaut ground ingress can be removed since crew would be launched on other vehicles (unless commercial crew falls through or LM uses Orion or something). De-coupling the exploration architecture from any one crewed launch vehicle (could use Soyuz to man the mission even if there was a problem with Dragon crew, if that wins commercial crew) may help increase the robustness of the architecture to failures.Also, it provides its own lifeboat for early testing or Mars-analogue missions.
The primary usefulness for ISS is as a location in space for practical testing of certain subsystems. High efficiency propulsion systems, long-duration life support systems, water recycling, hydroponics research, zero-g fire suppression systems, propellant transfer capabilities etc. All of these things need to be perfected and ISS is an optimal testbed site for such prototype engineering.But as a hub for actually staging missions in LEO, this station's design is a long way from being ideal. ISS is designed to be a research outpost -- and it should remain one.Ross.
Quote from: kraisee on 04/27/2010 12:44 amThe primary usefulness for ISS is as a location in space for practical testing of certain subsystems. High efficiency propulsion systems, long-duration life support systems, water recycling, hydroponics research, zero-g fire suppression systems, propellant transfer capabilities etc. All of these things need to be perfected and ISS is an optimal testbed site for such prototype engineering.But as a hub for actually staging missions in LEO, this station's design is a long way from being ideal. ISS is designed to be a research outpost -- and it should remain one.Ross.Why is it 'a long way from being ideal'? Back up your statements please.
Quote from: Rabidpanda on 04/27/2010 02:04 amQuote from: kraisee on 04/27/2010 12:44 amThe primary usefulness for ISS is as a location in space for practical testing of certain subsystems. High efficiency propulsion systems, long-duration life support systems, water recycling, hydroponics research, zero-g fire suppression systems, propellant transfer capabilities etc. All of these things need to be perfected and ISS is an optimal testbed site for such prototype engineering.But as a hub for actually staging missions in LEO, this station's design is a long way from being ideal. ISS is designed to be a research outpost -- and it should remain one.Ross.Why is it 'a long way from being ideal'? Back up your statements please.I'm sorry, but you're kidding right?Orbits & inclinations aside, if you follow the docking and undocking of just the shuttle, you'll see how careful they need to be with plume impingement on the science experiments and viewing windows. If you use the station as a staging point, you also introduce large quantities of propellants that will be transferred, greater risk of unnecessary traffic, debris generation, and collision.The purpose of ISS is for science.Build a lunar gateway station of you want to explore the stars...
There are already tons of propellant stored at the ISS. Just because you have to be careful docking doesn't mean it's a bad place to launch an exploration craft. Since when wouldn't you want to be careful docking?