DIRECT v2.0 - Thread 3

[daver]

Ross
 With Chris's article about EELV's capable of launching Orion.  It might be good timing for the Direct rebuttal. 

[Danny Dot]

The next question to ask is, does the crew at Moonbase need an "anytime abort-to-Earth" capability?

I have no doubt that this will be discussed, William.  However, I think I can safely say that having no 'lifeboat' on call for the outpost will be completely unacceptable to both the politicians and general public.  I have a difficult time imagining a scenario requiring immediate evacuation that would allow for the duration of a return flight.  Nonetheless, there is a significant emotional issue.

In any case, the big problem is the length of time it would take to prepare an Orion to fly to the moon to pick up the crew.  Any evacuation timeline would thus stretch from 3-5 days to maybe over a month.

I agree.  Now way are we going to have a crew on the moon without an Orion in lunar orbit.  What if the launch vehicle fails when attempted to send the recovery Orion to the moon?  Congress would not accept a crew on station without a way home, they aren't going to accept a crew on the moon without a way home.

Danny Deger

[Danny Dot]

snip
One other thing about the autonomous Orion: that only closes one anytime-abort loophole. What good is an Orion in orbit though, if you push the Start button in your Orion and nothing happens? Then you're going to need to wait at Moonbase until the rescue ship shows up. And since you have to have that capability anyway, it lessens the value of keeping an unmanned Orion in LLO.

I moved my response to the Orion/Altair section.  I recommend we move this discussion to there.  This is a Direct thread.

http://forum.nasaspaceflight.com/index.php?topic=16750.new#new

Danny Deger

[marsavian]

RaS is reporting that Cx just lost unattended access on Orion, i.e. only 3 astronauts on the surface with one staying behind like Apollo. If true the butchery and castration of Orion due to the crap Ares I continues ...

That doesn't have anything to do with Ares; it's due to a flight software scrub.

Due to cost ? What is going over way over cost in this launcher/payload equation ? I personally think 4 men on the lunar surface is a rubicon line, once you you don't have that why do you really need 2 launches per mission anyway ? It really would be just Apollo with steroids then. How can you set up a list of requirements, ESAS, and then continually break them as is expedient continually down the line and yet still refer to other parts as if they were sacrosanct ? The new administrator really needs to review this independently from the current Cx management who have picked up some very bad habits from his academic predecessor.

[yinzer]

When you get right down to it, what we call "Jupiter" is essentially the same launch vehicle which MSFC started developing itself as a result of the Advanced Launch System (ALS) / National Launch System (NLS) effort around 1988-1994.

--snip--

MSFC got there a decade before we ever dusted the concept off and proposed it again.   This vehicle was most certainly "Invented There" already and we have never tried to hide that heritage, in fact we've tried to make a fairly big thing out of it

As an outside observer, it doesn't seem like you are doing a very good job of communicating this point.

The summary document mentions NLS once, and says that it was an "effort to create a joint NASA In-Line Shuttle-Derived launch system remarkably similar in concept to the Jupiter-120."  The AIAA-2007-6231 paper uses NLS to refer to the Nova launch vehicle proposal from the 60s, and briefly mentions "earlier STS derived concepts ... required a new engine development program (STME)."

If you wanted to make a big deal out of the similarity to NLS, you'd say something like:

The last time this country seriously looked at an all-new launch vehicle development effort, the result was the National Launch System.  This recommended the development of a new LOX/LH2 engine known as the STME, and three new launch vehicles.  NLS-1 was a heavy lifter, using two shuttle SRBs and a core derived from the shuttle ET with four STMEs to carry 61 tons to LEO.  NLS-2 was a "medium lift" launch vehicle, using a stage-and-a-half configuration to carry 23 tons to LEO.  NLS-3 used 1 STME and an upper stage to carry 9 tons to LEO.  NLS was expected to cost $12 billion, $2 billion of which would go to develop the STME.  NLS did not proceed because there was not enough traffic predicted to make the high up-front costs worth it.

Since that time, the engine conceived of as the STME has been turned into the reality of the RS-68.  The NLS-3 became the Delta IV Medium.  Rather than using components from the heavy lifter to make NLS-2, components from the small vehicle were used to make NLS-2 - the Delta IV Heavy.

Over half of the initial NLS plan has been completed.  With Shuttle being retired and NASA setting out on a return to the moon, there are now payloads for the heavy lifter.  We suggest completing the NLS vision by building the heavy lifter - the time for NLS-1 is here.

With the proper upper stage, the NLS-1 core is big enough to support lunar missions in a two-launch architecture.  Innovative design will be required, but we know NASA is up to the challenge.

[Jorge]

RaS is reporting that Cx just lost unattended access on Orion, i.e. only 3 astronauts on the surface with one staying behind like Apollo. If true the butchery and castration of Orion due to the crap Ares I continues ...

That doesn't have anything to do with Ares; it's due to a flight software scrub.

Due to cost ?

Partially, but mostly due to schedule; flight software is threatening to become the long pole and NASA is far enough in that Brooks's Law applies. In other words, this would be occurring regardless of LV status.

Rest of post snipped due to irrelevance.

[Jorge]

Back onto the subject of this thread:

What good is an Orion in orbit though, if you push the Start button in your Orion and nothing happens?

Exactly how often has a hypergolic engine refused to start? I thought that their big selling point was that they were exceedingly reliable and it was amazingly difficult to stop one from working.

The engine isn't the only concern. Probably not even the biggest concern. I'd be more concerned about avionics not powering back up after six months of quiescence.

[Danny Dot]

Back onto the subject of this thread:

What good is an Orion in orbit though, if you push the Start button in your Orion and nothing happens?

Exactly how often has a hypergolic engine refused to start? I thought that their big selling point was that they were exceedingly reliable and it was amazingly difficult to stop one from working.

The engine isn't the only concern. Probably not even the biggest concern. I'd be more concerned about avionics not powering back up after six months of quiescence.

The good news is you need almost no avionics to get off the moon and do a redezvous.  Apollo had some nifty backup systems to save the crew with very little up and running.  For example no need for any gyros, IMUs, or computers.

I hope Altair has a similar backup system.

Danny Deger

[Danny Dot]

snip

Partially, but mostly due to schedule; flight software is threatening to become the long pole and NASA is far enough in that Brooks's Law applies. In other words, this would be occurring regardless of LV status.

Rest of post snipped due to irrelevance.

Thanks for the info.  I am glad NASA is on top of this issue at this early date.  Historically flight software is the long pole in the tent in complex manned systems.  Flying with limited flight software initially is very common in military aircraft.

Danny Deger

[Jorge]

Back onto the subject of this thread:

What good is an Orion in orbit though, if you push the Start button in your Orion and nothing happens?

Exactly how often has a hypergolic engine refused to start? I thought that their big selling point was that they were exceedingly reliable and it was amazingly difficult to stop one from working.

The engine isn't the only concern. Probably not even the biggest concern. I'd be more concerned about avionics not powering back up after six months of quiescence.

The good news is you need almost no avionics to get off the moon and do a redezvous.  Apollo had some nifty backup systems to save the crew with very little up and running.  For example no need for any gyros, IMUs, or computers.

I hope Altair has a similar backup system.

Danny Deger

I was actually referring to Orion. With Altair, you at least have the crew on the scene to attempt a repair. An unmanned Orion in lunar orbit is going to be vulnerable to a lot of little problems that could turn into fatal problems because there's no crew there to "give it a kick".

Partially agreed on Apollo. The backup systems involved gyros. In particular, the backup to the PGNS (AGS) had its own strapdown INS, called the Abort Sensor Assembly (ASA). The ASA had three accelerometers and three rate gyros, just like the PGNS IMU. The LM could do an automatic ascent on either the PGNS or the AGS if one of them failed. There were also manual ascent procedures for failed PGNS/degraded AGS and degraded PGNS/failed AGS, but there were no such procedures if both systems were hard-failed. The crew could attempt a manual ascent anyway, using the backup ignition for the APS and the direct coils from the ACA to the RCS to control attitude, but with only rough out-the window cues for attitude, and only the clock to shut down the engine, the odds of making an orbit the CSM could reach within LM ascent stage lifetime and still have enough prop for TEI were pretty low.

Nevertheless, the concept of dissimilar redundancy as used by Apollo does provide a good deal of protection against common-mode failures.

[Jorge]

snip

Partially, but mostly due to schedule; flight software is threatening to become the long pole and NASA is far enough in that Brooks's Law applies. In other words, this would be occurring regardless of LV status.

Rest of post snipped due to irrelevance.

Thanks for the info.  I am glad NASA is on top of this issue at this early date.  Historically flight software is the long pole in the tent in complex manned systems.  Flying with limited flight software initially is very common in military aircraft.

Yes, NASA is belatedly discovering the virtues of phased development, both in better use of manpower and spreading out the funding curve.

[Danny Dot]

snip

Partially agreed on Apollo. The backup systems involved gyros. In particular, the backup to the PGNS (AGS) had its own strapdown INS, called the Abort Sensor Assembly (ASA). The ASA had three accelerometers and three rate gyros, just like the PGNS IMU. The LM could do an automatic ascent on either the PGNS or the AGS if one of them failed. There were also manual ascent procedures for failed PGNS/degraded AGS and degraded PGNS/failed AGS, but there were no such procedures if both systems were hard-failed. The crew could attempt a manual ascent anyway, using the backup ignition for the APS and the direct coils from the ACA to the RCS to control attitude, but with only rough out-the window cues for attitude, and only the clock to shut down the engine, the odds of making an orbit the CSM could reach within LM ascent stage lifetime and still have enough prop for TEI were pretty low.

Nevertheless, the concept of dissimilar redundancy as used by Apollo does provide a good deal of protection against common-mode failures.

Thanks for the Apollo info.  It sounds like you really know your stuff.  I hope you are making good use of your knowledge somewhere at NASA today. 

I read a pre Apollo study done with pilots in a simulator that concluded an altimeter made the no gyro ascent much better.  I wonder if a separate radar altimeter was considered.

Danny Deger

[MP99]

The next question to ask is, does the crew at Moonbase need an "anytime abort-to-Earth" capability? It's kind of a corollary of Mars mission abort scenarios. Isn't it better to go for reliable moonbase systems and know you've got regular unmanned supply flights that can carry spare parts in the pipeline. Sick/injured on the Moon? I'd rather have a flight surgeon handy (even if only by telepresense) if it were me, than hope I could survive a 3 - 4 day evac flight to some handy ocean. If that anytime evac is dispensed with, the Orion pilot can go home as soon as the moonbase crew is landed.

NASA wants the early missions to take as few risks as possible, then maybe they can be more adventurous later. DIRECT seem to be using this as a guiding principal for their own efforts.

I guess NASA will just wait for autonomous loiter capability before they'll attempt a long-duration mission.

As far as preparing for Mars, I think the Moon missions are all about "hey, that would have been a disaster if we'd been a year away from home" rather than "sorry, we could have saved you guys if only we'd had an Orion in orbit".

One caveat - once you have a base with a couple of independent Habs, or at least a Hab & an Altair with extended life support, then one of the critical reasons for needing anytime return is reduced, but not enough to want to do without - there will always be accidents, and I'd guess the time to launch of a LON flight will be much longer than the flight time.

NB a single-launch J-246 (LV-41) carrying only an Orion and using the EDS for LOI has about 730m/s 700 m/s of spare delta-V. This could be used to perform a slightly quicker Lunar transit. More likely Or possibly you'd use it to perform a brute-force plane change, which would leave ~330 m/s unused delta-V in the SM to allow another quick-and-dirty plane change to get the evacuees home ASAP. (Mental image of an Orion with a blue flashing light on it!)


One other thought occurs, once you have a thriving outpost up and running (say 2020-ish)...

Ross's spreadsheets are landing ~22mT of cargo on the Lunar surface, and that would be just enough to land a fully-fuelled Orion "emergency return vehicle".

Of course, the problem is working out how to get the Orion back to LLO, but it would simplify / shorten the Earth return - no need to wait for rendezvous with Orion in LLO, just launch, plane change, TEI and you're on the way home.

SM MPS doesn't really have the T/W to perform the whole ascent, even if enough fuel were available, but could perform a ~330 m/s second stage burn (that's the delta-V normally used for 180-day station keeping and a rendezvous burn).

First stage would therefore need ~1,600 m/s Delta-V, lifting 22mT against 1/6th g. Maybe a solid, as something that could sit there for years without requiring maintenance, but that would be another ~15mT!

Hmm, that means you either need to land ~37mT in one go, assemble Orion onto the launcher on the Lunar surface, or re-fuel the lander. And none of those are easy options!

Probably the simplest would be to have a special-purpose SM having 2 or 3 engines and larger fuel tanks, then top off the tanks via a second cargo flight.

Still, it might be something that's within reach for DIRECT.

Is there anything that could be stripped out of the standard Orion to keep the weight down if it just needs to keep a crew alive for ~4 days for an emergency return dash?

cheers, Martin

PS I'll cross-post this into the Alternative Concept thread, but these seemed suitable thoughts to drop into the ongoing discussion here.


Edit: landed mass.

Edit 2: "More likely" -> "possibly" & "730 m/s" -> "700 m/s".

[Kaputnik]

When you get right down to it, what we call "Jupiter" is essentially the same launch vehicle which MSFC started developing itself as a result of the Advanced Launch System (ALS) / National Launch System (NLS) effort around 1988-1994.

That vehicle was technically quite achievable, and even passed its PDR with flying colors.   But it was Congress who refused to fund it any further simply because it would have been a third launch systems which would have to be paid for while the USAF Titan and NASA's Shuttle continued to be operated all in parallel.   They were willing to fund two, but not a third.

MSFC got there a decade before we ever dusted the concept off and proposed it again.   This vehicle was most certainly "Invented There" already and we have never tried to hide that heritage, in fact we've tried to make a fairly big thing out of it

Ross.

How close is Jupiter to NLS, really? Is everything below the upper stage virtually identical?
What were the upper stage options and design details for the NLS? i.e. did it have one, what engine(s) was/were on it, and was it common bulkhead?

[clongton]

I agree.  No way are we going to have a crew on the moon without an Orion in lunar orbit.  What if the launch vehicle fails when attempted to send the recovery Orion to the moon?  Congress would not accept a crew on station without a way home; they aren't going to accept a crew on the moon without a way home.

Danny Deger

Danny, you and I are from the same generation and if you recall Apollo, we did this with every mission. If the LM or the CSM had a failure it was game over for that crew. So what? We all knew it and we flew anyway. You make the best decisions you can, provide the best hardware you can, analyze the risks, decide if you will accept the risk or not, and then like Roy Orbison said “pack up the babies and grab the ole ladies and everyone goes”, shut up, get on the rocket and go.

This generations’ risk-adverse attitudes are stifling the space program. Everyone is scared to death they might get hurt or killed. Well my attitude is “so what?” We’re ALL going to die someday anyway and I’d MUCH rather be killed doing something I really, really want to do than of old age in a rocking chair with a geriatric nurse at my side. My only requirement is that I don't die for nothing. Life is an adventure meant to be tasted and lived, not watched from the sidelines. I am not interested in seats on the 50 yard line. I want to play!

I know several of the “older” crews, and every one of them will slide thru the Pearly Gates someday like sliding into home base in a cloud of dust and say “Wow, What a Ride!” Now that’s LIFE!

That’s how we went to the moon before, and that’s how we should do this again. We make careful (not stupid) choices, give it our best shot, go for it and don’t look back.