I wonder what the center picture is on this web page? And what the “15” means? Years until it flies…?

[Update late morning]

As a commenter notes, it’s not Chinese, but Korean, which I should have known by the name of the publication.

I wonder what the center picture is on this web page? And what the “15” means? Years until it flies…?

[Update late morning]

As a commenter notes, it’s not Chinese, but Korean, which I should have known by the name of the publication.

Most of the alternatives put forth against ESAS are different launch vehicle concepts, with no major changes to the nature of the lunar mission hardware or operations itself. Following up from his previous posts, Jon Goff has been exploring a different corner of the trade space, and has some interesting results. As a commenter points out there, he’s grossly overoptimistic on his vehicle weights, but it remains an interesting avenue to explore, regardless.

Thomas James notes something that I didn’t get around to noting yesterday–how limited in his thinking Stephen Hawking is:

If you’re going to have to terraform even barren worlds with Earth-like parameters, how is that so much different from developing Mars-like planets as well? Why be so picky?

In fact, there just happens to be a Mars-like planet nearby, which wouldn’t require anti-matter rockets or tens of thousands of years to reach…

And for that matter, there are plenty of asteroids and moons in the universe, not to mention the infinite possible variations on O’Neillian space settlements. Settling Earth-like planets isn’t the only way to preserve the species.

I haven’t read it yet, but Jack Schmitt’s new book looks interesting.

[Update a few minutes later]

Unfortunate typo of Dr./Senator Schmitt’s name has been fixed…

Jon Goff has some more good posts up on exploration (and particularly lunar) architectures. Here’s a key point that undercuts NASA’s rationale for HLVs:

Why doesn’t NASA land enough stuff to support 4 people for 6 months on a single lander? Or 6 people for a year? Because it would require much too big of a lander, which would cost too much to develop, and way too much to operate. By making the lander smaller, and less capable, but using LSR, ESAS provides a much cheaper approach than trying to do a Battlestar Galactica scale lunar lander. However, you could see where that logic goes…

And Doug Stanley more or less admitted it. He said that had the 4 people for 7 days edict not been “blessed” by Mike Griffin as one of the ground rules, that EELV based architectures would have traded a lot better compared to the chosen ESAS architecture. And he’s right. All the numbers I’ve run show that you could probably do a reasonable 2-man lunar architecture using st0ck, or nearly st0ck EELVs (or EELV equivalents like Falcon IX if it becomes available).

They admit the need for assembly on the moon, because they know that (as Jon notes) it’s completely unrealistic to get a full-up base to the surface with a single launch of any vehicle short of Sea Dragon (come to think of it, that’s one HLV that I could get behind, because it’s innovative and wouldn’t necessarily cost that much). Now admittedly, it is easier to do assembly in a gravity field (though in some ways, it’s harder as well, since with weight, you need cranes, etc.). But it’s not so much easier that they should have ruled out doing orbital assembly, something that we need to learn to do anyway, and that they will have to do for Mars, even with Ares V.

Again, as Jon points out, the entire architecture, and justification for an expensive (in both development and operations) heavy lifter is based on an arbitrary requirement–four crew for seven days. Remove that constraint, and the trade space blossoms tremendously. But it apparently doesn’t satisfy political imperatives, whatever their source.

Jon Goff has some more good posts up on exploration (and particularly lunar) architectures. Here’s a key point that undercuts NASA’s rationale for HLVs:

Why doesn’t NASA land enough stuff to support 4 people for 6 months on a single lander? Or 6 people for a year? Because it would require much too big of a lander, which would cost too much to develop, and way too much to operate. By making the lander smaller, and less capable, but using LSR, ESAS provides a much cheaper approach than trying to do a Battlestar Galactica scale lunar lander. However, you could see where that logic goes…

And Doug Stanley more or less admitted it. He said that had the 4 people for 7 days edict not been “blessed” by Mike Griffin as one of the ground rules, that EELV based architectures would have traded a lot better compared to the chosen ESAS architecture. And he’s right. All the numbers I’ve run show that you could probably do a reasonable 2-man lunar architecture using st0ck, or nearly st0ck EELVs (or EELV equivalents like Falcon IX if it becomes available).

They admit the need for assembly on the moon, because they know that (as Jon notes) it’s completely unrealistic to get a full-up base to the surface with a single launch of any vehicle short of Sea Dragon (come to think of it, that’s one HLV that I could get behind, because it’s innovative and wouldn’t necessarily cost that much). Now admittedly, it is easier to do assembly in a gravity field (though in some ways, it’s harder as well, since with weight, you need cranes, etc.). But it’s not so much easier that they should have ruled out doing orbital assembly, something that we need to learn to do anyway, and that they will have to do for Mars, even with Ares V.

Again, as Jon points out, the entire architecture, and justification for an expensive (in both development and operations) heavy lifter is based on an arbitrary requirement–four crew for seven days. Remove that constraint, and the trade space blossoms tremendously. But it apparently doesn’t satisfy political imperatives, whatever their source.

Jon Goff has some more good posts up on exploration (and particularly lunar) architectures. Here’s a key point that undercuts NASA’s rationale for HLVs:

Why doesn’t NASA land enough stuff to support 4 people for 6 months on a single lander? Or 6 people for a year? Because it would require much too big of a lander, which would cost too much to develop, and way too much to operate. By making the lander smaller, and less capable, but using LSR, ESAS provides a much cheaper approach than trying to do a Battlestar Galactica scale lunar lander. However, you could see where that logic goes…

And Doug Stanley more or less admitted it. He said that had the 4 people for 7 days edict not been “blessed” by Mike Griffin as one of the ground rules, that EELV based architectures would have traded a lot better compared to the chosen ESAS architecture. And he’s right. All the numbers I’ve run show that you could probably do a reasonable 2-man lunar architecture using st0ck, or nearly st0ck EELVs (or EELV equivalents like Falcon IX if it becomes available).

They admit the need for assembly on the moon, because they know that (as Jon notes) it’s completely unrealistic to get a full-up base to the surface with a single launch of any vehicle short of Sea Dragon (come to think of it, that’s one HLV that I could get behind, because it’s innovative and wouldn’t necessarily cost that much). Now admittedly, it is easier to do assembly in a gravity field (though in some ways, it’s harder as well, since with weight, you need cranes, etc.). But it’s not so much easier that they should have ruled out doing orbital assembly, something that we need to learn to do anyway, and that they will have to do for Mars, even with Ares V.

Again, as Jon points out, the entire architecture, and justification for an expensive (in both development and operations) heavy lifter is based on an arbitrary requirement–four crew for seven days. Remove that constraint, and the trade space blossoms tremendously. But it apparently doesn’t satisfy political imperatives, whatever their source.

When NASA first proposed a single-SRB-based launcher, one of the issues that jumped out immediately to many familiar with vehicle design and Shuttle design was roll control. As designed for the Shuttle, there are two SRBs, both of which can gimbal the engines. This allows roll control of the Shuttle stack by gimbaling them in opposite directions. But when there’s only one, the engine gimbal provides pitch and yaw control, but there’s no way for it to control roll.

There are two potential solutions to this–to modify the SRB itself to add roll-control thrusters, or to incorporate them into the new upper stage. The latter has the disadvantage of oversizing the roll-control system for the period after stage separation, which adds weight and affects performance, but it simplifies design by requiring only one system.

In any event, the concept seems to be in trouble. Now this certainly isn’t a show stopper, and issues like this are inevitable in the development of a new launch vehicle, but it’s just one more demonstration of the fact that deriving a new launcher from existing pieces isn’t as easy as has been advertised by many, both within and out of the agency.

[Late morning update]

Gary Hudson emails one other option:

There is a third possibility: let it roll. Depending on the rate and duration, it may not be a problem. Some current vehicles do this (Taurus, for one) and we are planning a subset of it for the AirLaunch QuickReach. In our case, we have a Stage Two roll thruster but its purpose is to limit the rate, not hold a specific roll attitude. Makes for a much small thruster. It is later used as part of the normally smaller sized Stage Two attitude control subsystem.

When NASA first proposed a single-SRB-based launcher, one of the issues that jumped out immediately to many familiar with vehicle design and Shuttle design was roll control. As designed for the Shuttle, there are two SRBs, both of which can gimbal the engines. This allows roll control of the Shuttle stack by gimbaling them in opposite directions. But when there’s only one, the engine gimbal provides pitch and yaw control, but there’s no way for it to control roll.

There are two potential solutions to this–to modify the SRB itself to add roll-control thrusters, or to incorporate them into the new upper stage. The latter has the disadvantage of oversizing the roll-control system for the period after stage separation, which adds weight and affects performance, but it simplifies design by requiring only one system.

In any event, the concept seems to be in trouble. Now this certainly isn’t a show stopper, and issues like this are inevitable in the development of a new launch vehicle, but it’s just one more demonstration of the fact that deriving a new launcher from existing pieces isn’t as easy as has been advertised by many, both within and out of the agency.

[Late morning update]

Gary Hudson emails one other option:

There is a third possibility: let it roll. Depending on the rate and duration, it may not be a problem. Some current vehicles do this (Taurus, for one) and we are planning a subset of it for the AirLaunch QuickReach. In our case, we have a Stage Two roll thruster but its purpose is to limit the rate, not hold a specific roll attitude. Makes for a much small thruster. It is later used as part of the normally smaller sized Stage Two attitude control subsystem.