Apollo 2.0 ?

[Sticks]

According to this link some critics the return to the moon, if it actually happens, will just be Apollo 2.0

Is this an accurate point?

As a side point there is also a link on that page to a video of the NASA briefing, and the first question was about funding and the cost of the clean up over Katrina, which Dr Griffen seemed to handle well.

[LunarOrbit]

*sigh*

NASA is getting criticism from both sides... one group is saying they are spending too much money, and apparently the other side is saying they aren't planning to spend enough. NASA just can't seem to win no matter what they do.

If they were planning to replace the shuttles with something that is a) 100% resuable, and b) not an Apollo-like capsule then we would have to expect a much higher cost and a much longer delay between shuttle retirement and first flight of the new spacecraft. In the meantime NASA employees would move on to other jobs and NASA would fall apart.

The current plan makes sense. Replace the shuttles with something well understood: Apollo-like capsules and shuttle derived rockets. This reduces development costs and development time. It also ensures that fewer jobs will be lost in the transition between the shuttles and CEV.

And as far as Katrina (and Rita) are concerned, it makes no sense at all to cut NASA funding to pay for the hurricane damage because most NASA employees live in the Gulf Coast area. They need their jobs now more than ever.

To be honest I'm sick of NASA bashing. If people can't see the good they do or the value of the dollars spent on NASA then it's their problem. Imagine how many people would not have evacuated New Orleans if there hadn't been weather satellites to warn them. Thank NASA for that.

[Sticks]

That seems to be Dr Griffen's line

Nobody cancelled the airforce

Do you think we could get our JayUtah to give them a hand with this?

[JayUtah]

Well, Boeing is already using my stuff to do the CEV design analysis. Unfortunately I do not get to see the design. :-(

[JayUtah]

I've actually known about the NASA return-to-moon strategy for several weeks now. Boeing sent them to me, but didn't indicate whether I could share them. (Turns out they really weren't a secret -- lots of people got advance release materials.)

At first glance I was extremely dismayed at the degree to which STS technology was being reused. My knee-jerk response was that NASA was trying to keep the United Space Alliance companies in business after 2010 when the remaining shuttle orbiters are retired.

SSMEs are expensive and actually older technology. But they do happen to be extremely capable engines.

The ET's only problem is that it sheds foam. Big deal; every rocket with cryogenic fuel sheds something. Shedding is only a problem when you bolt delicate payload to the side of the rocket. Put it on top, like everyone else, and it works fine.

I have a certain affinity for the SRBs because ATK Thiokol is the space contractor geographically closest to me, and where I have the most friends working. But I never thought they'd survive beyond the shuttle program. It is encouraging to see them reappear as strap-ons to a new booster, but somewhat puzzling to see them as the booster stage to the manned ascent vehicle for the CEV.

Historically the unveiling of a new NASA manned space initiative has been accompanied by proposals for next-generation flight hardware containing significant advances over the state of the art. Unlike the commercial space industry, NASA has more leeway to extend the overall space capability. So the extensive reuse of STS hardware leaves me wondering whether NASA simply doesn't care to be bold anymore.

Using STS hardware expendably seems wasteful. Well, the ET was meant from the start to be as cheap to manufacture as possible, since it would not be reused. But the SRBs and the SSMEs, all of which seem to be expended in the new designs, are expensive, having been engineered for multiple flights. If return to the moon is to be done on expended hardware, it would be wise to do it on cheaply expended hardware.

The SRB production line is still operating at Thiokol and can continue to be for the foreseeable future. I'm not sure about the SSME production line.

The Rocketdyne J-2S has been discussed to. It's the updated version of the Saturn V upper-stage engine. It has considerably less thrust than the SSME, but also considerably lower cost.

The spec'ing of rocket engines for a particular application is always very difficult because there are so many variables in mutual conflict. Despite its price the SSME is the cream of the crop when it comes to rocket powerplants. It also has the advantage of existing -- other engines being considered are either in development or out of production.

Human-rating is something that will have to take center stage given NASA's recent safety lapses. The SSME is human-rated, as are all the other STS cast-offs being employed in the new booster designs. The SRBs are still human-rated, and the Apollo-style LES for the CEV launch means that a Challenger-type accident is far less a danger. Many of the contemplated failure modes for the SRBs involve the dangers of firing them in tandem, so I do believe NASA's estimates that the SRB-based CEV launch vehicle is considerably safer than the STS.

SRBs have been engineered for reusability too, and it seems they will be expended in these missions. However, SRB manufacturing is considerably less costly than for other booster types. Expending SRBs seems less problematic for me than expending SSMEs.

While NASA can be faulted for not having taken a bigger step this time around, the main pressure on NASA right now is safety. NASA has lost most of its earlier "can-do" image. Regardless of how much we bad-mouth the STS designs for safety, the elements of them have been human-rated for 25 years and have accumulated a vast engineering knowledge base. Very rarely in that case does it make engineering sense to abandon known, proven designs for unknown designs that merely promise to be better.

NASA has actually, quite cleverly, salvaged what was good and innovative from the STS development while eliminating its known design and operational defects. Get rid of the orbiter and its limitations and you have the makings of a very competent heavy-lift delivery system.

As for the CEV and LSAM, the designs clearly derive from Apollo, and my attitude there is, "don't fix it if it ain't broke." They are scaled-up designs, to be sure. but the Apollo CSM and LM designs are still some of the most successful and well-considered designs in the aerospace inventory. It would be folly not to use them. And a careful study reveals that there are new earth-landing systems and propulsion systems being considered. Liquid methane, for example. It's not just a copy of Apollo technology, but an extension of them.

Right now we're looking at the Block I CEV. The Block II CEV is supposedly the interplanetary version and is many years down the road.

I expect the LSAM to undergo the predictable series of design evolutions, but the notion of ascent and descent stages is just plain smart. It may end up looking more like the Apollo LM, or more like something else. The current LSAM concepts have clean lines and basic shapes, just like the early LM concepts. One innovation I'd like to see is the ability to use descent stages as construction modules for a base.

But I think the current proposal has a lot more going for it than we give it credit for. It's safe; it's achievable; it's extensible; and it capitalizes on what we already know.

[Bob B.]

jayutah said:

Using STS hardware expendably seems wasteful. Well, the ET was meant from the start to be as cheap to manufacture as possible, since it would not be reused. But the SRBs and the SSMEs, all of which seem to be expended in the new designs, are expensive, having been engineered for multiple flights.

A couple months ago I read some stuff about the Shuttle-derived launch vehicles and I recall seeing a diagram of the crew launch vehicle that showed a SRB recovery system. I don't know if this is also true of the heavy-lift cargo vehicle but I don't see why the SRBs couldn't be recoverable.

It's unfortunate the SSMEs will be expendable but there doesn't seem to be any way around it. The crew launch vehicle uses only one SSME, which makes sense since it is already man-rated. The cargo vehicle will use five SSMEs; do you think it would be cheaper to use three RS-68s? The thrust and sea level specific impulse is almost the same, but the vacuum specific impluse is a little less.

[PeterB]

I’m quite impressed with the announcements. I like the idea of using well-tried technology and mating it with well tried methods.

I compared the proposed systems with previous accidents and near-accidents on Dr Karl’s Self Service Science Forum, and concluded that the only likely source of problems would be some sort of unanticipated interaction such as struck Apollo 13. Challenger and Columbia style accidents aren’t likely to recur. Or at least, if there’s a blow-by from an SRB, it can only conceivably cause problems on the unmanned launch of the lunar lander.

As for those who consider the system a throw-back to older ways of doing things, how similar are Russian rockets and engines to those which launched Sputnik and Vostok? (Genuine question, I’d like to know!)

A couple of questions come to mind with the systems.

Are any of the stages going to be recovered? I get the impression that the first stage SRBs could be recovered. But I assume that the pumps and engines on the first stage of the unmanned launcher wouldn’t cope well with a dunking.

Also, how would the manned launcher SRB first stage be steered? My understanding is that the Shuttle SRBs aren’t steered. Would there be plans to gimbal the engine (which seems expensive and potentially dangerous) or would they use an RCS system? Or are there other methods for steering?

[Bob B.]

peterb said:

As for those who consider the system a throw-back to older ways of doing things, how similar are Russian rockets and engines to those which launched Sputnik and Vostok? (Genuine question, I’d like to know!)

The rocket used today to launch Soyuz is derived from the same rocket that launched Sputnik in 1957. If its not broke, don’t fix it.

peterb said:

Are any of the stages going to be recovered? I get the impression that the first stage SRBs could be recovered. But I assume that the pumps and engines on the first stage of the unmanned launcher wouldn’t cope well with a dunking.

I’ve seen an illustration of the crew launch vehicle that showed a recovery system for the first stage solid booster, so there are apparently plans to reuse it. I assume the SRBs on the cargo vehicle will also be recovered but I have not confirmed this. The SRBs are jettisoned at relatively low altitude but the liquid-fueled stages will propel the vehicle to high altitude, thus it is very unlikely they could survive reentry. I’m assuming all the tanks and engines will be used only once.

peterb said:

Also, how would the manned launcher SRB first stage be steered? My understanding is that the Shuttle SRBs aren’t steered. Would there be plans to gimbal the engine (which seems expensive and potentially dangerous) or would they use an RCS system? Or are there other methods for steering?

The Shuttle SRBs already have thrust vectoring. The nozzle can be gimbaled +8 degrees by hydraulic actuators.

[JayUtah]

Also, how would the manned launcher SRB first stage be steered? My understanding is that the Shuttle SRBs aren’t steered.

Nope. The majority of STS first-stage ascent steering is accomplished currently by gimballing the SRB nozzles.

[scooter]

The only issue with the SRB launcher is roll. The shuttle stack is rolled during stage 1 by asymetric SRB gimballing as well as gimballing the SSMEs. They will need to gevelop some sort of roll control for the "single stick" design.

Dave

[rocketdad]

Scooter: I think the Shuttle rolls to present the cargo bay/window side to the ground for orbital attitude, nothing more. Part of the deal with roll is the shuttle is an asymetrical object, so it sits the pad one way, orbits another, then lands in a third way.

The cargo-lift part of the new system will use the SRB/SME combo (or something equiv to SME by the time they get the thing to the pad) so it can roll or not as needed, but the crew launcher doesn't need to roll. The SBR-based (single-stick) vehicle could use low-thrust attitude motors once in orbit to get lined up for docking with the lander unit. No roll during thrust phase required, just point the nose the right way.

[JayUtah]

Guidance platforms and their software work best when the pitch motions are considered to be within the orbital plane and yaw motions are considered perpendicular to the plane. So the single-stick SRB vehicle will want to have roll control. There is no magic launch azimuth that works for all launches -- some roll is always necessary in order to align the guidance axes with the intended flight path. The SRBs currently have a rudimentary RCS for the STS booster separation sequence, and it could live at the top of the SRB stage in the new design and provide roll control.

[rocketdad]

jayutah said:

Guidance platforms and their software work best when the pitch motions are considered to be within the orbital plane and yaw motions are considered perpendicular to the plane. So the single-stick SRB vehicle will want to have roll control. There is no magic launch azimuth that works for all launches -- some roll is always necessary in order to align the guidance axes with the intended flight path. The SRBs currently have a rudimentary RCS for the STS booster separation sequence, and it could live at the top of the SRB stage in the new design and provide roll control.

Proving that I'm a carpenter and not a rocket scientist. Thanks, Jay. You've pointed me in a new research direction... was that a yaw or a roll? Hmm.

[rustylander]

Maybe they're planning to go to the moon for real this time!

[LunarOrbit]

rustylander said:

Maybe they're planning to go to the moon for real this time!

Using technology similar to Apollo... hmmm... if they can do it now why couldn't they have done it then?