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#1 2007-01-19 04:42:17
- Michael Bloxham
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- From: Auckland, New Zealand
- Registered: 2002-03-31
- Posts: 426
Re: Quick & Dirty Orbiter Replacement
I'd have to say I prefer a Direct Shuttle Derivative (DSD or DIRECT) over the Ares I ('The Stick'). http://www.directlauncher.com/ It's quicker, cheaper, safer, and more versatile. However, if we go down this route, we may still need to develop an Ares V style vehicle for proper lunar and mars missions. Therefore, it might be better to revive an even cheaper option than DIRECT for the interem: A crewed version of Shuttle-C. Here's my proposal: mount a 'compromise Orion' capsule atop the expendable side mounted pod. Have the module sit near where the entry hatch is now on the shuttle, and power the pod with two cheap standard RS-68's.
This vehicle will be a direct 'Orbiter Replacement': It shouldn't require any noticeable changes to infrastructure at all. This design will be the cheapest possible to develop; I don't see where you could cut costs further with this one (except if you use a cluster of 3 SSME's, but the increased launch costs won't be worth it). The payload might be only 70 tonnes or less (due to the less efficient RS-68's), but with the weight of the Orion, this will still leave more payload than what can fit in a Shuttle bay.
Again, has this or similar design been discussed in any detail before? Forgive me if it has.
- Mike, Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]
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#2 2007-01-19 08:00:00
- SpaceNut
- Administrator
- From: New Hampshire
- Registered: 2004-07-22
- Posts: 29,438
Re: Quick & Dirty Orbiter Replacement
Will post some links first:
Shuttle C
Worked on during the years 1987-1990, but then abandoned when it was found that the concept had no cost advantage over existing expenable launch vehicles.
Version that is disposable whem it comes to the SSME:
August 1989 NASA studied a version of the Shuttle-C with two Advanced Solid Rocket Mortors (ASRM's) in place of the standard RSRM's. This would increase the payload by 4500 kg, but also require use of a new 10 m x 30 m payload module.
Manufacturer: Martin. LEO Payload: 81,500 kg (179,600 lb). to: 407 km Orbit. at: 28.50 degrees
We have had many discusions here about shuttle C and it boils done to not cutting down the costs, excess shuttle army size that makes it not favored in the past.
A few points of concern still are the foam strikes and no fuel in the pod section to power away from the ET. Adding the Launch escape tower as in the orion CEV only helps.
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#3 2007-01-19 13:12:22
- GCNRevenger
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- From: Earth
- Registered: 2003-10-14
- Posts: 6,056
Re: Quick & Dirty Orbiter Replacement
This is an awful idea
70MT, or even 50MT is way overkill for a "1.5-launch" arrangement, and offers no performance benefit over "1.5" if you went with a two-launch scheme and dropped Ares-V. But "isn't overkill a good thing" you say? No! If the CEV is so heavy, then the EDS stage launched with Ares-V/Direct/etc will not have the power to perform TLI. And just "forget it then, just slap some sand bags or brass bricks under it," WTH? Thats asinine to waste all that power and rocket cost.
This thing won't be as safe as Ares-I either, for the same reasons as "Direct:" large segmented solid rockets adjacent to a huge tank of liquid rocket fuel. This is a significant risk that cannot be fixed. Also there are more liquid fueled rockets involved like "Direct" which likewise increases risk. RS-68 isn't even man-rated either.
And the "oh you don't have to change the infrastructure" is a red-herring, since we're going to change it anyway for Ares-V, following which this new rocket will probably be incompatible.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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#4 2007-01-19 18:19:34
- Michael Bloxham
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- From: Auckland, New Zealand
- Registered: 2002-03-31
- Posts: 426
Re: Quick & Dirty Orbiter Replacement
Comparing A Direct Orbiter Replacement with Ares V or DIRECT, I would draw the same conclusion. However, comparing it to the shuttle is a different story.
What if the Shuttle had another orbiter-related hiccup? We could accelerate Orion development by integrating Shuttle life support and auxilliary systems into it, and quickly build a cheap and easy Direct Orbiter Replacement to continue ISS operations.
While this is happening, work will begin on a slightly more ambitious main tank design (10m x 80m or so, 6 or 7 RS-68b's), but keeping the 4-seg SRB's.
The 5-segs don't have a future and aren't worth it, IMO. Best to focus on the core stage.
- Mike, Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]
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#5 2007-01-19 20:51:24
- GCNRevenger
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- From: Earth
- Registered: 2003-10-14
- Posts: 6,056
Re: Quick & Dirty Orbiter Replacement
No no no, no more "Shuttle Backup" plans! No more!
Shuttle will fly and the ISS will be "done," then will be forgotten as it should be. if Shuttle doesn't, then the ISS won't be 100% finished, so what. Then it won't be 100% finished, big deal. We've got actual stuff of importance to do, none of which involves the station and its construction or operation. Let the Russians have at it if they want.
This idea of an "Orion orbiter replacement" is not workable because you need much more than just the capsule to do the Shuttle's job: the ISS payloads, many of which are loose bits, are all designed to be pulled from side and not pushed from the end. Hence you are going to need a cargo bay.
Also they will need a robot arm in said bay to hand off components to the ISS arm, since it is not long enough itself.
Lastly, the "payload" module has to execute the circulization burn, which the Orion can't since it will be riding on the top of the stack, further complicating its mass/complexity/etc.
And you are still putting an Orion capsule on top of a stack with segmented boosters right next to the fuel tank. Shuttle life support systems are bulky too, and would not likely fit in Orion at all, and would need major redesign anyway.
Its not quick, its not cheap, and its not easy plus its not safe either.
And whats this nonsense about the SRBs not having a future? I don't think you know what you are talking about, the "big cryogenic rocket" concept as a horrible knee-capping problem of a terrible thrust-to-weight ratio, which imposes a severe gravitational loss payload penalty. For instance, the Delta-IV gains (or loses) almost double the payload if you just add dinky little strap-on SRMs to it.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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#6 2007-01-19 22:54:05
- Michael Bloxham
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- From: Auckland, New Zealand
- Registered: 2002-03-31
- Posts: 426
Re: Quick & Dirty Orbiter Replacement
I sincerely hope you are right. I hate the shuttle and ISS just as much as you do. However, I cannot say whether NASA will ever be sufficiently pardoned from either before 2020.
But your right. IMO, NASA is stuck between a rock and a hard place with this one.
- Mike, Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]
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#7 2007-01-20 06:25:09
- Michael Bloxham
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- From: Auckland, New Zealand
- Registered: 2002-03-31
- Posts: 426
Re: Quick & Dirty Orbiter Replacement
Something like this:
- Mike, Member of the [b][url=http://cleanslate.editboard.com]Clean Slate Society[/url][/b]
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