Another change in plans for the Shuttle successor?

[IceManHG]

There is yet another option. The Jupiter Direct system: It uses existing Shuttle parts like the main external fuel tank. This idea was pitched to the Obama team by some NASA guys going over thier bosses heads. I have no idea what sort of backlash this will have at NASA.

http://www.popularmechanics.com/science/air_space/4298615.html

[Twabi2]

Rather funny picture. I don't know a thing about rockets when compared to the accumulated knowledge of NASA, but still I can spot some "strange" arguments in there...

For example:

Nasa says the extra engine doubles the chance that something will fail.

Then why the hell does the shuttle have 3 engines, 5 GPC's, 7 astronauts, 3 APU's, 2 launch pads, ... It only raises the chance of failure!  OH NOES!!



-Toine

[uri_ba]

well it's different, because the SSMEs are started on the ground and tested before lift-off.. the Engines on the second stage MUST work, without starting them up prior to lift-off.

so it's easier to make one system run then two..
but they did have 5 engines on Saturn V's second stage - which didn't really help them if one would fail (Apollo 6)

[Twabi2]

That doesn't change a thing. Let's suppose that 1 out of every 25 second-stage engines fails (completely made up number btw, just a random number).

That means there's a 4% chance that the second stage engine won't start, which means big problems (no abort possible).
If you have 2 engines, that means an 8% chance that one engine fails, but you still have the possibility of abort. The chance that both fail is 0,16% tough. I know which one I'd prefer if I were an astronaut!

[HMSEndeavorreborn]

JLM I meant if the shuttle were to work the same way it does here. Launch, orbit, land. To land on the moon is simple enough, getting off the moon again is where the problem arises, you've gotta break about 3km/s to break free of the moons gravity. Where's the fuel/stack coming from then?

[JLM]

Are you menaing, where is all that fuel going to be stored?

[HMSEndeavorreborn]

Well yes its the fuel I'm looking at, the SSMEs chew through alot of fuel per second. I dont see how there'd be a way to store it in the current generation of shuttle, or a possible future shuttle.

[uri_ba]

this shuttle doesn't really need to land on the moon. the lander can be stored in the PLB. and fuel isn't the problem - you can modify the ET so that it will work almost like the B-58 Hustler centerline tank - two halfs and you can jettison the bottom half once it is empty.

[RMS Driver]

There was some discussion about this on the wikipedia boards. The problem is not just the extra fuel that would be needed, but getting it off the ground. Unless the shuttle only carried a extremely light-weight LEO/LTO payload, the extra fuel and the larger SLWT would exceed the shuttle's weight limit. Either the SSMEs would have to be upgraded or the weight of the launch systems would have to be reduced.

Another problem with using the current Shuttle is, obviously, its age. The GPCs use one Megabyte (Mb) of RAM each. The onboard N2 and He tanks are years past their designed lifetime, and could fail at any time.

While I love the Shuttle, I support her retirement, but only when a concrete plan is formed for the future. I also believe that there is a middle ground with the Ares/Orion program. I like the simplicity of the Jupiter approach, but on the oter hand, NASA is no new-guy in this field. But one thing is for sure, NASA needs to get their act together or we may be relying on 3rd party contractors or even Russia to fufill our ISS resupply needs.

[IceManHG]

Thats why we need a new generation of Shuttle. It seems to me that NASA is moving backward in time with the creation of the Ares vehicles.

[desktopsimmer]

I've stayed away from this for many reasons Yes the shuttle should be retired, Yes they need a resusable and controlable craft, X-38?

The Orion/Ares/Jupiter/Constellation Program does seem a step backwards to me. The only items that would be a step forward would be heat shield, launch vehicle and computers, everything else is tried and tested, and expensive.

IMHO, I thought that a X-38 type of vehicle was going to be the best way forward. The Crew section could be completely re-usable, the orbital engines are discarded, the computers/guidence was going to be designed around 'off-the-shelf' technology. All the Serviceable parts are the Thermal system, Thruster, Control Surfaces, Computers and Life Support. The shuttle had Engines and the sheer size of it made service a financial nightmare. X-38 would of been a lot cheaper

I spoke to a NASA engineer post Columbia and he said and other couldn't understand why the x-38 could of been modified for the Delta launch vehicle with a lower engine rating or something like the Constellation launch vehicle (this has been around for years as a replacement for Delta/Titan). An X-38 could land almost anywhere on land, and is 'steerable' in case of problems. A capsule is not this, it has a very limited landing area as the craft needs an area that is big enough to cope with any problem re-entering. Speak to RKA about how many Soyuz have missed the 'ideal' landing zone. I still don't know if Orion is designed for landing on soil or sea, or both. I've seen one test on soil, which the craft was a write off. The parachute system failed.



Apparently, and in theory, the X-38 could land without the parafoil (this was simulated), but the speed was deemed to high and the craft could of rolled and crashed.

P.S.  I've heard that even 2017 is too optimistic for the first manned Ares Mission to LEO. 

[JLM]

Yeah, judging from that picture, I don't want to ride in that hunk of junk!

Anyway, I think they should make a reusable fuel tank, just try somehow to make it land in the atlantic ocean, and make it able to reenter the atmosphere without damage.

If not always reusable, at least make it reusable a couple of times. As it costs currently for the Super Light Weight Tank (SLWT) $5 million for just one

[leswhitham]

Here's an idea, and I know NASA has probably thought of it before, but why not have the SSME's redisigned for restarts as has been proposed before and have a shuttle permanently stationed (ie not to return to earth) at the ISS if we were going to use this as a go-between to the moon?  It seems awfully silly to waste such a great machine. 
Also with regards to the discarded ETs - why not use those as a permanent fuel supply storage facilities for the shuttle at a distance from the the ISS? Then we could just send up fuel supplies via Progress type supply rockets when needed.  Or even better still rather than have a fuel depot on orbit we could just send fuel supplies up to the ISS, have the shuttle use the RMS to grapple the fuel pod (it wouldn't need to be that big so you'd still have loads of room for lunar excursion modules etc), put it in the cargo bay and then shuttle off to the moon.  Makes perfect sense to me.  Easy peasy.  When back at the ISS, jettison the fuel pod to burn up in the atmosphere ready for the next one.  Then when returning astronauts need to come back to earth - CRV it! 
Just a thought

[RMS Driver]

Thats a great idea, but it would involve many costly repairs to the shuttle. Also, I'm sure NASA is not crazy about the idea of using four vehicles (ISS, Ares, STS, Lunar lander) and moving large loads of fuel around those vehicles.

[uri_ba]

inclination differance is too large to make an efficient TLI from ISS.
ISS inc is 57.1 and the moon inc is around 6.

in addition the payload loads losses due to the need to launch to 51deg inclination orbit make it totally ineffective compared to an 28 deg inc orbit (due east launch from KSC)