Bruce NS/NSTI: questions for Alan Ladwig (NASA PAO)

NUKE ROCKY44 · Senior Member

Bruce NS/NSTI: questions for Alan Ladwig (NASA PAO)

John · Senior Member

I got around to listen to that episode tonight. You asked some good questions and made some excellent points. It's good that NTR and Pu-238 are in the budget. I hope that they stay there!

Naturally we are going to need some way to get the nuclear rockets into orbit. They need a lot of LH2 as well. So we need some sort of a HLV and the orbit all fuel depots. Dallas Beinhoff was on Monday with an excellent discussing about depots. He got to the key point after a time that we need a reusable rocket to get cost advanges from them. At the same time the requirements of the depots will lead to a sortie rate that justifies reusability.

-- Edited by John on Wednesday 5th of May 2010 03:33:37 AM

NUKE ROCKY44 · Senior Member

Yeah...John but how do you respond to Zubrin's charge that orbital fuel depot is a bad idea and he passed on some suspect technical reasons why he feels this way.
Listen to his idea around end of show. I sort of agree with a lot of what he says but there are issues he has that are not correct.

He does not understand neutronic of isotope inventory and their degradation with respect to for example, a catastrophic explosion on a spacecraft powered by NTR reactor in a park/space vehicle yard at Lagrangian points. This inventory would not effect LEO orbits and earth atmosphere. Not to mention the reactor itself has poisons that would tamp long life U235 material.

http://www.thespaceshow.com/detail.asp?q=1352

The other issue is cooling regimes between NTR and NEP. Again, he does not understand that both reactors types have safety cooling circuit breakers one method involving a 'party whistle' blow up column filled with manifold charcoal type dust inside 'party whistle' I read about it in a paper need to find it.

John · Senior Member

As I unterstand it there are some concerns about the transfer of cryogenics in zero-g. I seems to have to do with the mixture or something like that of vapor and liquid. I've heard this somewhere before. I was the one who had sent in an e-mail question to Dallas Beinhoff on this subject (I couldn't call in live). Beinhoff didn't see any show stopper with the transfer process. Dueling experts!

I'm going to have listen to the Zubrin show again as there was so much content. However, I do get the drift that Zubrin is so focus on getting to Mars ASAP that anything that distract from that is to be opposed. I believe he said that a nuclear VASIMR would weight 20,000 tons (I need to check that one). That seems a bit extreme.

NUKE ROCKY44 · Senior Member

I heard the program with Beinhoff he's selling the concept as a neutral in-space tech. which is smart to avoid the engineering 'snake pits' that dot the landscape.

http://www.thespaceshow.com/detail.asp?q=1355

You're correct John from "Huntsville, Alabama". Maybe, David wants you to transfer from aircraft to civilian space isn't civilian aircraft more lucrative? Beinhoff does note, cryo-transfer of H2&LOX has never been done but He, N have history been transfered in small scale. He's saying couplings and arm valves with injection of acetylene accelerant not big problem. boil-off to me is not a big deal if tanks have the micrometor shield insulation that's already in use in orbit and small cryo-coolers which are small plus the tanks are sandwiched on either side as a solar blind (shade) to assist in cooling there should be no problem.
Wonder why after so many years went by since 2007 when he was called in to write up presentation studies.

Crazy space program, this still only a proposed program (budget FY-2011) to do not yet a POR.

Flexibility is his keyword for in-space ops. Obviously I agree since I'm RLV type person anyway. 20-90 ton mass delivery boost sounds OK to me vs no depot. He also covered the universality angle quite well. And he talks about a propane, LOX+ methane, H2O2, heavy ion noble gases for EP's all can work depending on mission.
I guess, Beinhoff favors berthing (arms) to depot instead of docking-cool. 150ton cap. depot serviceable in 1.5 yrs-wow. 50 ton single launch by ULA depot where is this? 5 years build, cost @ $400 million-1 billion-big spread there.

On your idea on earth ocean re-entry liquid booster engines wouldn't you need a protective shroud to wrap over turbo pumps, tubing, exhaust bell, etc.?

-- Edited by NUKE ROCKY44 on Sunday 9th of May 2010 02:50:22 AM

John · Senior Member

You're correct John from "Huntsville, Alabama".

David has changed that to "John from Atlanta" on his show synopsis. He has a lot "John" that call the program. I can recall a "John from Montana" to name one who calls or emails frequently. That are others and I was trying to avoid becoming two people.

On your idea on earth ocean re-entry liquid booster engines wouldn't you need a protective shroud to wrap over turbo pumps, tubing, exhaust bell, etc.?

The basic idea goes back to Dr. von Braun. This is how he proposed recovering his first two stages of his circa 1950 concept. I can remember a newspaper clipping from my Space scrapbook that envisioned a Saturn V first stage parachuting back for recovery and eventual reuse.

Just about all of the liquid-fueled rockets in the U.S. inventory except the Saturn series has their origins in military missile programs. These designs were for nuclear weapon delivery and so were naturally expendable. The Saturns were focused on the moon race and so an enduring capability wasn't a requirement either.

The reason for ocean recovery is simple, i.e. that is where they come down. Certainly this is the case for a first-stage. In search for the most economical reusable system I went back to the von Braun idea. I also found a smaller concept by Kistler (now Kistler Rocketplane) that builds on this idea. It is also the eventual concept for SpaceX. Finally and most significantly the Shuttle SRBs have been recovered this way for nearly 30 years now.

You, David, and Mark Bray (who is from Huntsville currently) have raised the question of what happens to liquid-fueled boosters. The flow control values would be closed before splash down. So the sea water would get to the turbo pumps or the tanks. It would get into the engines of course. I think that this unavoidable. The Kistler concept includes inflatable cushions in addition to parachutes to soften the splashdown. They perhaps have a floatation role as well. But, I'm sure that water is going to get in the engines.

The main issue there is corrosion and what it would take to clean them out enough to use again. The SRBs spend quite a bit of time in the water and they are reused. It is obvious that there would have to be some clean up and servicing between flights even without these issues. I'm really open to be informed on all of this.

The second stage has the added problem of reentry thermal protection. In addition to parachutes (a low drag drogue would likely be required and addition to main 'chutes) we would need some sort of a deployable heat shielding system. There has been research and demonstration work on these concepts.

The key point is that this is the lowest cost reusable system. Basically there are only modest changes from the design of expendable rockets. The structure would have to be stronger, corrosion protection would be at premium, and we would have added weight for thermal protection, parachutes, etc. However, when compared with true fly-back systems that are hypersonic gliders with wings, landing gear, aerodynamic performance requirements, etc. these are clearly lower cost. The big issue is feasibility.

NUKE ROCKY44 · Senior Member

Ok I'll take a look. Redstone missles comprise saturn they where bundled together.
[LINK]

"The basic idea goes back to Dr. von Braun. This is how he proposed recovering his first two stages of his circa 1950 concept. I can remember a newspaper clipping from my Space scrapbook that envisioned a Saturn V first stage parachuting back for recovery and eventual reuse. Just about all of the liquid-fueled rockets in the U.S. inventory except the Saturn series has their origins in military missile programs."

For sure Dr. von Braun was in the RVL club.

"Looking back, I can see now how minimal, even primitive, our facilities were at the time, both in the control center and in the blockhouse a massively reinforced structure placed as close as prudently possible to the launch pad where the guys who were responsible for the actual functioning of the rocket manned their posts. We tended to talk about "the Germans in the blockhouse" largely because Wernher von Braun and his cohorts, who had worked on the rocket programs, came to the United States after Germany's defeat in World War II. They were originally stationed near El Paso, Texas, and tested captured V-2 rockets for the military at the White Sands, New Mexico, test range. Later they were moved to permanent facilities at Huntsville, Alabama, and worked for the Army Redstone Arsenal. Most of the Germans became American citizens, adopting Huntsville as their home. In 1960 rocket development at the Redstone Arsenal was transferred to the newly formed Marshall Space Flight Center (MSFC), and von Braun, along with nearly 100 other German scientists and technicians, began work on a powerful series of rockets called Saturn I."[link]

FALCON 9 first stage recovery is going to be hairy dropped in a salty drink merlin 1C x 9 @ 7,700 kg (17,000 lbs).

Merlin Vacuum Engine Expansion Nozzle

"We recently fabricated and formed the first flight expansion nozzle for the Merlin Vacuum second stage engine. Made of a thin, high temperature alloy, the large expansion nozzle extends from the regeneratively cooled portion of the engine, and improves its performance in the vacuum of space. Standing 2.7 meters (9 feet) tall and 2.4 m (8 ft) in diameter, it resembles the nozzle used on our Falcon 1's second stage engine, only larger. The Merlin Vacuum engine expansion nozzle measures 2.7 meters (9 feet) tall, and most of it has a wall thickness of about 1/3 of a millimeter (1/64 of an inch)." [LINK]

My concern on engine shutdown is the exhaust nozzle and turbo pumps cooled flushed with helium to lower temp. before drop (quenched) in sea water to prevent warping and jarring effect of drop on equipment.
Since you sealed engines after shutdown do tanks vent off or purged with inert gas for safe recovery? I'm not the rocket engineer and maybe they looked into the issues but if they didn't what effect does it have on turnaround fixes & costs?

Dr. von Braun would not approve of this RVL unless all possible issues were resolved for full recovery and short turnaround & costs. The man was a stickler for efficiency.

Second stage is about ballutes, chutes, tiles, engines shroud and ditto 1st. stage remedies for rentry. Irvin aerospace http://www.airborne-sys.com/

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NUKE ROCKY44 · Senior Member

The Space show welcomes back Gary Hudson to the show. Gary is a long time rocketeer, was CEO of Rotary Rocket, involved with Air Launch LLC and much more.

I asked him the following questions via email into show:

I'm in favor of RVL in the long run for space development.

-Can a liquid rocket (1st stage) engine survive in seawater recovery for turnaround prep for flight?

-Can a liquid rocket ( 2nd stage ) engine survive re-entry & seawater recovery for turnaround prep for flight?

Paraphrasing he's said, this already has history NASA on various occasions in past has recovered (fished out) booster liquid rocket engines from the ocean and had them working also U.S. Navy (USN) has experience and USAF has had jet engines submerged in ocean flushed cleaned and working again.

-What is his position for use of nuclear propulsion and power in space?

He approves of nuke space for the above.

-What's wrong if any problem of earth/space environment with L1, L2, L3, L4, points for assembly/storage of reactor?

He attempted to answer this question but due to time constraints it meant further discussion applicable to a research paper.

PS. Would you approve of a list or petition of people in favor of the various forms of nuclear power & propulsion in space.

John · Senior Member

Thanks for asking ... I'll check that out tomorrow after David posts it. I've had some e-mail exchanges with an aerospace engineer who is critical. I'm still somewhat positive. I'm conviced that we can keep the sea water out of the turbopumps and tanks which is a big deal. The boosters can't be super thin like the early Atlas and Titan ICBMs. I something like the structural strength of the Saturn V plus pressurization plus inflatable cushions might just do the trick.

The engineer I was in contact with was of the opinion that the boosters would so beat up by the ocean that the idea wouldn't work of the other hand. A fall back would be to recover the just the engines, pumps, and other systems as parts for new expendables. The idea isn't all or nothing. However if we could recover the whole boosters in reusable shape that would be the best! biggrin

-- Edited by John on Thursday 13th of May 2010 12:25:10 AM

NUKE ROCKY44 · Senior Member

The idea isn't all or nothing. However if we could recover the whole boosters in reusable shape that would be the best!

I'm with you John. I think you're on to something for RVL.