Re: Ares vs DIRECT
- From: Ross B Tierney <kraisee@xxxxxxxxxxxxxx>
- Date: Tue, 04 Dec 2007 15:49:26 -0500
John Schilling wrote:
On Thu, 22 Nov 2007 12:36:27 -0500, Michael Gallagher
<mikejoe7g@xxxxxxxxx> wrote:
On Tue, 20 Nov 2007 17:22:28 -0500, Ross B Tierney
<kraisee@xxxxxxxxxxxxxx> wrote:
Yes: http://www.directlauncher.com/
Discussions take place on the forum at nasaspaceflight.com
Ross B Tierney.
www.directlauncher.com
Thanks; I looked at the proposal. And I agree with Derek on one
point: One of the assumptions behind Direct is the only thing Orion
would be used for is missions to the Moon. But Orion is meant to be a
workhorse, delivering supplies and crews to the station as well as
Moon (and Mars) missions. So an LEO booster like Ares 1 is required.
If Bush's successor were to scrap the VSE and Ares V and confine Orion
to LEO, you'll need a booster for that application anyway. Which
brings us back to Ares 1 (or something with Ares 1's capability).
I'm sure you could arrange to fly Orion to ISS on top of an Ares V,
if you were really wedded to the one-launcher idea. Massive overkill,
but doable.
And surprisingly similar to what the DIRECT people are proposing...
Been unable to get back on here for a while, but let me answer a few things.
First, we actually have a dedicate Crew Launch Vehicle (CLV) configuration broadly comparable to Ares-I, called the Jupiter-120.
It's primary task is to fly Orion to station and won't be involved in the Lunar missions at all. Jupiter-120 has about 46 tons (I always assume metric BTW) of lift capability and a payload shroud that makes the Saturn-V shorud looks mall. This means it is capable of launching the 23 ton Orion spacecraft and roughly another 20 tons of additional cargo if required - an incredibly valuable ability we have today with Shuttle, but which we will lose in the future with Ares-I.
And don't assume that Jupiter-120 *has* to fly with another payload all the time. When unneeded, we would suggest a simple 20 ton water tank be flown as ballast. It would provide an additional barrier between the launcher and the spacecraft in the case of any future unpleasant contingencies and would likely offer useful additional protection to the crew in the event they had to perform an abort.
Senator Nelson recently asked Administrator Griffin how the $1.5bn Alpha Magnetic Spectrometer (AMS) payload could possibly still be flown by NASA - the response was in the negative - that it will likely be grounded for ever. This system would re-open that option, whereas the much smaller Ares-I can not lift any additional payloads with the Orion.
While the Jupiter-120 configuration is not used in the Lunar program, it shares all of its hardware with the Lunar configuration (Jupiter-232) but consists of the same boosters, Core Stage and engines, just with the central RS-68 engine removed.
This vehicle would cost $140m per flight, compared to Ares-I's $130m variable cost, so isn't very different.
Where the Jupiter makes a big difference in cost though, is by only developing one vehicle (saving upwards of $10bn) and by only operating one launch vehicle instead of two (saving another $1bn in fixed operations costs every year).
This means that while Jupiter-120 is certainly more powerful than really needed for pure Crew lift duties, overall it is a very powerful and cost-effective solution indeed.
Ross B Tierney
www.directlauncher.com
.
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