DIRECT v3.0 - Thread 1

[Ben the Space Brit]

It's an exponential problem, and I guarantee the prop mass would end up far, far higher than the mass of the heat shield.

That's probably why spaceflight theorists like aerobraking so much.

[gladiator1332]

Ross-

A while back you mentioned a "showstopper" for Ares I, and as I recall, you stated the abort scenario was not the issue, but rather, something else.

I was curious when this other showstopper will be discussed, and where it will be posted.  Will it go on the Ares I development thread?

Thanks.

The only real 'showstoppers' which I'm aware of with Ares-I is that it a) has not been an affordable proposition at any time of its existence, b) a crewed Ares-I will never actually fly until at least 7 years after Shuttle has retired -- even if CxP cuts the test program down to nothing and increases risks at every level by doing so, and c) it has such p*ss-poor performance that its margins are nothing but a very bad joke.

But, other than that, its fine...   

Ross.

I believe the probable Mike Griffin response to the above list would be "So what?" 

[William Barton]

A question for anyone who wishes to answer.

If "we" are able to carry with us additional fuel supply to the moon, might we have enough that on the return to Earth that the mission not need to immediately enter the atmosphere, but rather reenters Earth orbit, and then lands when and where it wants?

hopefully that makes some degree of sense???  Thank you!

By the way - Ross, great job on NPR - as everyone else has stated!

Others will probably answer with more details, but the velocity change needed to enter earth orbit on a Lunar return would require a velocity change similar to a TLI burn on the outbound leg.  In Apollo, that velocity change was handled during atmospheric reentry.  Depending on mass it could be a substantial amount of fuel.

With propellant depots in LEO and (say) L1/2, so long as you didn't mind the cost of lugging all the fuel and oxydizer from wherever you got it (Earth/Moon/NEOs, whatever), it seems possible (if costly) to visualize an Apollo-sized reusable lunar architecture. So long as you could refuel the SIVB at L1/2, you could just lug everything back and forth until it wore out. I think it would be an STS-class "academic exercise," but how much more expensive would it really be than expending the hardware every time? What we really learned with STS is, the cost break-point for RLV is right around what STS was originally supposed to have (and never came close).

[fotoguzzi]

great job on the NPR show - got the points across really well.

I just ran through it twice.  Ross certainly has a gift for tailoring the message to the audience.  He spent a lot of time on the budget because that was the theme at the time he came on, but he also managed to fully describe the concept and get in some simple to understand performance numbers.  All under heavy pressure!

I think an argument that is maybe inherent, but often not voiced, is that the NASA trade system that the astronauts alluded to has produced a great vehicle . . . and then they went and attached the Orbiter to it!

I sympathize with an Ares V engineer who wonders if his work will come to fruition, but at the same time I imagine the feelings of a Shuttle core stage designer who gets to see his thirty-year-old creation leap off the pad and out of Earth orbit.

Modify: Oh, and I forgot to wish happy third birthday to the DIRECT idea!

http://forum.nasaspaceflight.com/index.php?topic=3307.60

It probably looked a bit shinier four years from the end of Shuttle than one year!

[A_M_Swallow]

Money and fuel can be saved if the EML-1 to LEO propellant comes directly from LEO/Earth, without taking any long cuts via the Moon.

An electric propulsion tanker can probably use less fuel cycling between LEO and L1 than a chemical upper stage would use to transport the propellant.

Since about 50 tonnes of chemical propellant are needed to put a capsule at L1 into a LEO orbit manned trips will almost certainly perform a direct re-entry.

The best L1 to Earth re-entry route needs investigating.

[Lobo]

Got a question for the direct team.

I've heard a few people here mention a cargo lunar lander.  I know this isn't anything with baseline, but is it something you guys have an idea about sitting on the back burner?

The idea is good, landing extra cargo for support of longer duration missions or multiple missions to a single location.  Just wondering if it's something you've thought about for Jupiter, and if so, would you launch a lighter one on a single J-246 launch, or a very heavy one on a J-130/J-246 type luanch?
What kind of landed masses would be achievable?

Just curious.

[luke strawwalker]

luke & lancer,
Can I ask you guys to start a specific spin-off thread to discuss the model rockets?

The discussion is great and I've been following along closely myself (one day I'd like to build one of these myself!) but we have a hard enough time justifying that DIRECT isn't a 'paper rocket' without including discussion here of real 'paper rockets'!    It could very easily lead a newcomer to the concept to the wrong conclusion.

This concern goes away if it gets its own dedicated thread

Ross.

Sure, but I think we're done... Lancer can PM me if he needs any more info.  Thanks Ross...  

PS great job guys...   OL JR

[Xentry]

If "we" are able to carry with us additional fuel supply to the moon, might we have enough that on the return to Earth that the mission not need to immediately enter the atmosphere, but rather reenters Earth orbit, and then lands when and where it wants?

As some of the previous answers have noted, if you want to enter Earth orbit coming from a lunar return you might need to spend a large amount of fuel, which because you need to take to the Moon in the first place, will significantly impact your entire mass budget.
I suspect what you might be looking for is something called aerocapture followed by a later re-entry, that is:

1. you make a short atmospheric pass at a relatively high altitude in order to deplete just the right amount of energy to get into Earth orbit - this will hopefully get you into an elliptical orbit, with a high point at a safe enough altitude to remain outside the Earth's atmosphere, and a low point well within the atmosphere
2. when you reach the highest point in this preliminary orbit, you spend on the order of 100m/s to circularise the orbit at that safe altitude
3. once you've decided when and where to leave Earth orbit, you spend another 100m/s to bring the low point in the new orbit to well within the atmosphere, and
4. you perform the final re-entry and land.

[JMSC]

Ross-

A while back you mentioned a "showstopper" for Ares I, and as I recall, you stated the abort scenario was not the issue, but rather, something else.

I was curious when this other showstopper will be discussed, and where it will be posted.  Will it go on the Ares I development thread?

Thanks.

I think you're actually referring to the Showstopper for Not-Shuttle-C -- which was the Abort motor always rupturing the LOX Tank above, and in close proximity to, the Orion.

With this latest SRB report, I'm actually even more concerned about the Not-Shuttle-C placing the Orion so much closer to the SRB's too, but that's a side issue (excuse the pun).

The only real 'showstoppers' which I'm aware of with Ares-I is that it a) has not been an affordable proposition at any time of its existence, b) a crewed Ares-I will never actually fly until at least 7 years after Shuttle has retired -- even if CxP cuts the test program down to nothing and increases risks at every level by doing so, and c) it has such p*ss-poor performance that its margins are nothing but a very bad joke.

But, other than that, its fine...   

Ross.

Ross, I guess you don't consider the latest Air Force analysis showing a 1 minute blackzone for Ares I's flight regime a showstopper, even though imaginary blackzones were show stoppers for EELVs?  Just to be sure on this one, I would think it would be a showstopper, but I guess in Ares I case the issue would fall under just throw even more money at the problem to build a more powerful launch escape system.

John

[zapkitty]

Ross, I guess you don't consider the latest Air Force analysis showing a 1 minute blackzone for Ares I's flight regime a showstopper, even though imaginary blackzones were show stoppers for EELVs?  Just to be sure on this one, I would think it would be a showstopper, but I guess in Ares I case the issue would fall under just throw even more money at the problem to build a more powerful launch escape system.

John

Ares I can't lift a heavier LAS... no matter how much money you throw at it.

It's at negative performance margins now, with Orion gutted and the Orion SM having to act as a third stage to even finish the ascent to orbit.

[Michael Bloxham]

Ross,

With all the talk around re-focusing NASA towards a Mars goal (I've just latley heard Neil, Buzz, Mike, & Gene all support this) I was wondering what your own views on the subject are, and to what degree you have shared these with the Augustine guys.

Cheers,

- Mike

[MP99]

On a related subject, I was wondering re depots.

Obviously, this was part of the initial Augustine presentation on opening day. Have depots / phase 3 been a part of the later, more detailed submissions?

Obviously, if you can say.

cheers, Martin

[drdave]

On a related subject, I was wondering re depots.

Obviously, this was part of the initial Augustine presentation on opening day. Have depots / phase 3 been a part of the later, more detailed submissions?

Obviously, if you can say.

cheers, Martin

Martin, see <a href="http://forum.nasaspaceflight.com/index.php?topic=17295.msg439977#msg439977>my recent synopsis[/url] of the Augustine Commission sub-group "Exploration Beyond LEO"

[kttopdad]

With all the talk around re-focusing NASA towards a Mars goal (I've just latley heard Neil, Buzz, Mike, & Gene all support this) I was wondering what your own views on the subject are, and to what degree you have shared these with the Augustine guys.

Obviously, this was part of the initial Augustine presentation on opening day. Have depots / phase 3 been a part of the later, more detailed submissions?

I just heard Buzz being interviewed on POTUS (Sirius/XM radio station).  He was all over depots (and their commercial implications) and moving on to Mars.  He has a meeting with Mr. Obama this afternoon, and that's what he's going to lobby for.  Everything he said in the 15-minute interview seemed to fit very well with what DIRECT has been advocating all along.  Very interesting conversation. 

I know that Ross/Chuck have talked with Mr. Aldrin in the past, and that he was marginally in sync with DIRECT (approaching things from a different-but-not-hostile direction).  Does anyone have a read on his position re: DIRECT these days?

[drdave]

Propellant Deposts are #5 on the list of questions being explored by the "Exploration Beyond LEO" sub-group of the Augustine Commission.  And #8 is another component advocated by the Direct Team.

Specifically, the “Exploration Beyond LEO” subcommittee will examine the following questions:

1. What are the appropriate destinations and sequences of exploration for human exploration beyond LEO;

2. What should be the mode of surface exploration  (if any);

3. What is the strategy within the human space flight program for coordinating human and robotic exploration;

4. What are the assumed launch vehicle(s) to LEO (in terms of mass to orbit and shroud diameter);

5. What are the options for in-space fuel/oxidizer storage and transfer;

6. What is the role that space technology research and development will play;

7. What is our strategy for engaging international partners in the development of the program;

8. What is our strategy for engaging commercial entities?

With all the talk around re-focusing NASA towards a Mars goal (I've just latley heard Neil, Buzz, Mike, & Gene all support this) I was wondering what your own views on the subject are, and to what degree you have shared these with the Augustine guys.

Obviously, this was part of the initial Augustine presentation on opening day. Have depots / phase 3 been a part of the later, more detailed submissions?

I just heard Buzz being interviewed on POTUS (Sirius/XM radio station).  He was all over depots (and their commercial implications) and moving on to Mars.  He has a meeting with Mr. Obama this afternoon, and that's what he's going to lobby for.  Everything he said in the 15-minute interview seemed to fit very well with what DIRECT has been advocating all along.  Very interesting conversation. 

I know that Ross/Chuck have talked with Mr. Aldrin in the past, and that he was marginally in sync with DIRECT (approaching things from a different-but-not-hostile direction).  Does anyone have a read on his position re: DIRECT these days?

[kttopdad]

Propellant Deposts are #5 on the list of questions being explored by the "Exploration Beyond LEO" sub-group of the Augustine Commission.  And #8 is another component advocated by the Direct Team.

Right.  But my questions related to Buzz, not the Commission.  Does anyone know how Buzz feels towards DIRECT these days?  His interview statements sounded like they came straight out of the DIRECT 3.0 literature.  I feel certain he's not a full-fledged amazing people, but do we have a reading on his feelings these days?  He's going to chat with the Prez in a couple of hours. 

[fotoguzzi]

The team has been relatively quiet of late.  I keep refreshing the baseball card page expecting to see a Fratricide-Safe sticker to go along with the Blackzone-Safe one.

[zapkitty]

The team has been relatively quiet of late.  I keep refreshing the baseball card page expecting to see a Fratricide-Safe sticker to go along with the Blackzone-Safe one.

1) The Fratricide Zone is a Blackzone.

2) The problem may well affect Jupiter somewhat, although Jupiter does not have Ares I's %100 kill zone.

3) I thought they were going to ditch those stickers before the Augustine presentation?

[kch]

I was wondering what your own views on the subject are

Mars should be the primary goal and no later than 2019. I was born almost 15 years after the Apollo 11 flight and I definitely not want to be fifty (or older) when the first crew lands on Mars.

I'm already over fifty, and we're not even back to the Moon yet, much less Mars ... just hoping it happens while I'm still here to see it! 

[robertross]

For those centered on Direct, there's an interesting post in the EELV thread 

Looks like Ares-I might go the way of the dodo....enter Jupiter.

http://forum.nasaspaceflight.com/index.php?topic=17671.msg441996#msg441996