New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: This forum has successfully made it through the upgraded. Please login.
  1. Index
  2. » Search
  3. » Posts by Ad Astra

#1 Re: Human missions » China second manned launch coverage; » 2005-10-18 18:08:36

The space station picture has been around for quite some time, as has the model showing the taikonaut driving a rover on the moon.  When China starts its space station, I doubt that it will resemble the configuration in the picture, as China is learning a lot about space operations that it didn't know in 1999-2000 when the model was displayed.

There has been some confusion on the web, with people passing off pics of the Shenzhou descent and landing as real when they were actually made on a computer.  Only the photos of the capsule after landing are authentic, and even then I suspect that they were taken long after the crew had been recovered.

#2 Re: Single Stage To Orbit » Realistic solutions to the difficulties of SSTO? » 2005-10-18 18:03:38

I fail to see what's so impressive about HyFly.  Air-to-Air missiles routinely travel at Mach 3 and Mach 4.

#3 Re: Human missions » China second manned launch coverage; » 2005-10-18 01:44:21

From all reports I've read, Shenzhou 7 will be a solo mission featuring a spacewalk.  The docking will not occur until missions 8 and 9.

The speculation is that Shenzhou 6 was, more or less, the final form of the Shenzhou spacecraft.  I would hazard a guess that Shenzhou 5 did not have a habitable "Orbital Module," because Yang Liwei never left his seat.  There has been some speculation that the Shenzhou 5 orbital module was really an electronic intelligence payload.  It will be interesting to see what happens with the Shenzhou 6 orbital module, which is still presumably orbiting the earth.

#4 Re: Single Stage To Orbit » Realistic solutions to the difficulties of SSTO? » 2005-10-17 19:52:11

To clarify a few points about the X-43:

1) X-43A was not cancelled; it was only budgeted for three flights, which were completed in fall 2004.  The program was then set up for the near-term X-43C and far term X-43D and X-43B.  These programs were cancelled in early 2004 with the announcement of VSE.

2) X-43C was an Air Force program with a hydrocarbon-powered scramjet.  This was cancelled around the same time as NASA's X-43B&D.

3) The technology is certainly worth pursuing, but it has more utility for hypersonic passenger planes than for spaceflight.  Seeing as how we lack a supersonic transport, it's premature to be talking about a hypersonic one.  Until an economic case can be built, hypersonic propulsion will not see a high priority within NASA.

#5 Re: Human missions » China second manned launch coverage; » 2005-10-16 21:56:52

I had read elsewhere that a female taikonaut would fly aboard Shenzhou 8.  I don't know if the People's Liberation Army Air Force has female pilots; if not, I would dismiss this maneuver as a stunt.

What I'd like to know is if Shenzhou 7 will launch in 2006 or 2007.  With the success of the current mission, China has no excuse (aside from funding priorities) to wait two years until the next mission.  In contrast, NASA launched 10 manned Gemini missions in 1965-6.  Shenzhou is a more advanced craft than Gemini (which may justify some additional time spent on test missions,) but the booster is very similar (hypergolic propellants.  Some have dismissed Long March's predecessor, the DF-5, as a knockoff of the Titan II.)

#6 Re: Human missions » Shuttle ST-121 Atlantis » 2005-10-15 15:02:38

My sources in the shuttle program say that May will be a stretch, so don't cross your fingers.  At least the foam problem didn't turn out to be as hard to solve as previously thought.

#7 Re: Human missions » China second manned launch coverage; » 2005-10-15 14:40:19

While China was more open about media coverage of Shenzhou 6 than it was last time, I'd still like to know a lot more.  The US media deserves admonishment for not making a big deal of it, but it's also true that they have little to report due to the terse nature of the Chinese government.

Most troubling is the news that the capsule's orbit is "slipping" due to earth's gravitational pull  This report from the BBC leaves much to the imagination, and is probably based on an awkward translation from a Chinese news source.  What prompted Chinese space officials to order an orbital correction?  What was the result?  Was the crew ever in danger?  These are questions we deserve answers to.

#8 Re: Single Stage To Orbit » Realistic solutions to the difficulties of SSTO? » 2005-09-23 20:22:52

Hmm... I don't see any info about the dry mass of StarRaker on the Marcus Lindroos website.  Perhaps Rockwell didn't want to reveal the fact that StarRaker wouldn't work.  The craft might have been able to do Mach 6 on turboramjets (Mach 4 is more realistic,) but it would still need to accelerate from Mach 6 to Mach 25 on rocket power.  This still requires a huge fuel fraction.  Winged vehicles will never have the required fuel fractions with current-generation or even near-term materials.

#9 Re: Human missions » Shuttle ST-121 Atlantis » 2005-09-23 20:15:14

Amen to that Cindy, but what Griffin said - that killing Shuttle/ISS now would save no money - disturbs me.

I don't recall Griffin explicitly saying that shuttle cancellation wouldn't save money, and I'm sorry if my comments gave that impression.

What I am saying is that the moon program will utilize the vast majority of the shuttle infrastructure and workforce, so it will cost roughly the same (with the marginal costs of a moon flight being somewhat higher than those of shuttle.)

The only way to save money from losing the shuttle is if you lose the army along with it.  This will not happen as long as we're planning on returning to the moon.

#10 Re: Human missions » NASA's Moon Mission » 2005-09-22 22:38:20

Despite long-term plans of exciting moon missions, the space program between 2011 and 2018 seems pretty dull.  The only manned missions that will launch from the US will be Stick + CEV flights to ISS.  We'll probably conduct 2-3 of these missions per year.  Yawn.  But I suppose that in the 2016-2017 time period we'll see shakedown flights of the lunar CEV, massive in-line SDV, and LSAM, like what happened in Apollo 7-10.

#11 Re: Human missions » Shuttle ST-121 Atlantis » 2005-09-22 22:34:17

Despite Griffin's well-laid plans, OMB is seriously considering immediate termination of the shuttle.  Depending on the disposition of the shuttle army, such a move would either a) strip NASA of the workforce needed for lunar return, or b) end the shuttle program without any real cost savings because the shuttle army would still be on the payrolls.

Of course, if Rita destroys mission control, the shuttle and moon programs will be in serious trouble.  At least ISS can be controlled from Russia.  It's one benefit of international cooperation.

#12 Re: Human missions » NASA's Moon Mission » 2005-09-22 22:00:48

Yes Nasa has made that commercial statement for ISS cargo but the are no other launch sites owned or operated other than by Boeing and Lockheed at this time all others are suborbital. Not to mention that probably neither would sell off the shelf items to others for which some one else could build these ships.

What about SpaceX's pads at Vandenberg and Kwajelein?  What about the Taurus and Minotaur pads used by Orbital Sciences (or, for that matter, the Pegasus, which uses no pad.)  A space startup can get its own pads.  Right now, LC-46 at the Cape is available.

Regarding our reasons for going back to the moon:
At this point, NASA Watch's Keith Cowing is correct in that NASA is doing a poor job explaining to American taxpayers why they should fund the lunar return.  From what I can tell, NASA has two major obectives:

1. Establish a base that can be used to demonstrate man's ability to work in space and conduct science on the moon.

2. Prepare for a Mars mission by exploiting lunar oxygen, demonstrating life support systems, and developing methane engines.

Mars wasn't mentioned by Michael Griffin.  For space enthusiasts, this will make them lose faith in the "why" behind lunar return.  However, the media would savage NASA and the president at the first mention of Mars.  The media view is that Mars is a multibillion-dollar boondoggle, and that humans on Mars is unnecessary because we can send robots to Mars on the cheap (an interesting reply can be found on the 9/22 NASA Watch, from none other than Mars rover principle investigator Steven Squyers.)

#13 Re: Human missions » NASA's Moon Mission » 2005-09-21 19:09:42

And I am concerned about the $104 billion price tag for return to the Moon. Mars Direct was budgetted at $20 billion for a single mission plus $2 billion for each additional, or $30 billion for 7 missions. NASA's design reference mission with 6 crew per and all the rest was budgetted at $55 billion. The Moon is closer, it should be easier; why does it cost $104 billion?

I don't regard the Mars Direct cost estimate as relaible.  The $50 million figure for Mars Semi-Direct is probably a lot closer to the truth.  Still, I tend to think that even $50 million is too low.  After all, Semi-Direct used nuclear-thermal rockets, and it used the Saturn V-derived "Comet" instead of a cheaper SDV.

The cost model for lunar return isn't helped by the need to develop "Stick."  Also working against it is the delayed development schedule.  Programs that don't bite the financial bullet up-front tend to bleed to death in the long run.

And how did NASA get the $104 billion figure?  Simple.  They figured an annual budget of $8 bil for manned spaceflight (roughly what it is today) multiplied by 13 years between 2005 and 2018.  A huge chunk of this is the fixed cost of the shuttle & ISS programs, which will not decrease thanks to the shuttle-derived decision.  When Bob Zubrin came up with $20 bil for Mars Direct, was he factoring this cost into his calculations?

#14 Re: Human missions » SRB booster for CEV » 2005-09-20 18:43:27

It's not realistic to think we can just end the shuttle program now and work on the new rockets.  To get appreciable cost savings, you'd have to lay off the shuttle workers--the same workers you need back on the job when the CEV, Stick, and "Magnum" are ready.  A smooth transition from shuttle flights to the stick in 2011-2012 will ensure that the cape's workforce stays on the job and stays sharp.

As much as I'd love to give ISS to the Russians and the other partners, I don't think they'd take it in its current state.  They want it completed with the modules that can only be delivered by the fragile shuttle.  Of course, we could sell them the shuttle and tell them to finish ISS by themselves.  Kill two birds with one stone.

#15 Re: Single Stage To Orbit » Realistic solutions to the difficulties of SSTO? » 2005-09-20 18:30:59

To be honest, NASA should have come up with a true RLV to replace the shuttle before embarking on the ISS or lunar return.  The shuttle has been the ISS's choke point, because it wasn't reliable enough to meet the ISS assembly schedule.  Of course, almost all of the modules were designed to be flown on the shuttle.  NASA crossed its fingers and hoped there wouldn't be another shuttle accident; the agency couldn't beat the odds, and ISS suffered.

Likewise, if you're a fan of Rand Simberg, you're currently lamenting the lack of reusability in NASA's moon plan.  With a reliable RLV, you could launch the moon ships in 20-ton chunks, then fuel them up and send them on their merry way. 

We currently fear on-orbit construction because our current launchers are too hard to launch in a timely fashion, and not reliable enough.  If we can make rockets reliable like airliners, high flight rates will be easy, orbital assembly will be easy, and going to the moon and beyond will be affordable.

Don't expect to see NASA building an RLV.  When Rutan & co. see a market for one, they will build it.  Until then, they'll keep flying suborbitally to raise awareness (and lower costs) of space tourism.

#16 Re: Single Stage To Orbit » Realistic solutions to the difficulties of SSTO? » 2005-09-20 00:51:14

In response to the last two posts:

Rockwell's X-33 design looked a lot like the shuttle (it even used an SSME,) but it really had no common parts with NASA's albatross.  Some of the Rockwell drawings even show two tails instead of one.

The Rockwell design wasn't bad.  It relied on tried and true lifting reentry (unlike the radical powered landing from the DC-X and the eventual McDD X-33 design,) and the structural concept was much more conventional than LockMart's.  In short, it represented the lowest risk of the three designs.

Could the Rockwell design have scaled up into an SSTO?  Heck no.  But none of the competing X-33 designs had a shot, either.  That was the folly of the X-33 program: there was little traceability between a subscale Mach 15 rocket and an orbital rocket with a 50,000 pound payload.  The contractors tried.  NASA should be blamed for fostering an unsound idea.

As far as launch from a 747: this was not considered for the space shuttle, but it was the focus for Boeing and Rockwell mini-shuttles in the late 70's and early 80's.  The Air Force wanted a small shuttlecraft that could reach orbit on short notice.  This has been a recurring theme with the Air Force.  Plenty of money has been spent over the years on various studies, and lots of splendid artwork has been released, but no hardware has been publicly demonstrated.

Launching from the back of a 747 is not all it's cracked up to be.  For starters, the 747 doesn't give much of a speed boost--only Mach 0.8.  Further, the idea of captive carry on top of the mothership gives engineers goosebumps.  Most expect the rocketplane to come crashing down on the mothership, as was the case with the D-21 + M-21 combo.

Russia's MAKS was the most advanced of the "launch from a cargo aircraft" concepts, but there are still doubts about its viability.  Would it be able to maintain control after release from the An-225?  Could the orbiter weight be kept down so the appropriate fuel fraction could be achieved? Mach 0.8 is not a significant head start, seeing as how the rocket has to reach Mach 25+.

The best air-launch proposal I've seen is a moribund concept called "Bladerunner."  Aside from a lawsuit from Ridley Scott, I don't see any problems with it.  The rocket would be extracted from a cargo plane, but would still be flying at Mach 0.7.  Its scissor wings would generate lift, unlike the ill-conceived "AirLaunch" being promoted by Gary Hudson and t/Space.  The two-stage approach ensured that room for growth and realistic fuel fractions would be maintained.

#17 Re: Single Stage To Orbit » Realistic solutions to the difficulties of SSTO? » 2005-09-19 20:51:44

One vehicle that does meat the requirement of reentry landing on a runway and a quick turnaround time is the x-37. However, the X-37 only has a 4% payload fraction and we do not have enough information from the program to know if it caries enough fuel for a useful second stage or why the payload fraction is so bad. In all likelihood the X-37 falls far short of a useful reusable second stage vehicle. However, I believe the basic design is good and with a larger vehicle, lighter materials, and less stuff inside it that would be useful to the military but might not be needed by NASA the X-37 could form a good starting point for a second stage vehicle.

X-37 is really a payload, like the manned capsules before it.  It doesn't have much propellant, other than for maneuvering once on-orbit.  X-37's orbital capabilities are moot right now because there isn't any money to fund it after the White Knight drop tests end.

Would the X-37 shape make for a good booster?  I wouldn't think so, because the shape has a low fineness ratio and would produce a lot of drag.  Many re-entry vehicles are designed to be draggy so they bleed off energy in the atmosphere.

I've often looked at the X-34 as a good shape for a booster.  But we have to remember that the X-34's wings were designed for the pitching maneuver that would have followed separation from the mothership.  So the X-34's wings were probably oversized for a booster that is only going to be generating lift after its propellants are used up.

A good shape for the flyback booster was the Rockwell X-33 concept.  Looking like a bloated X-34, it was a winged rocket that would have glided to a landing after a suborbital ~Mach 15 flight.

#18 Re: Single Stage To Orbit » Realistic solutions to the difficulties of SSTO? » 2005-09-18 21:06:02

Because scramjet-powered craft fly depressed trajectories and have a finite top speed (I think Mach 12 is the thermodynamic limit, regardless of which materials are used,) I don't think they are useful for spacecraft.  A scramjet-powered first stage could be used as part of a TSTO, but this introduces the challenge of supersonic separation between the booster and orbiter while in the atmosphere.

The best application of scramjets is for high-speed aircraft, like airliners or bombers.  The production scramjets will really be Rocket-based combined cycles or turbine-based combined cycles.  Because these vehicles stay in the atmosphere, there is no need for a difficult stage separation, or building up enough speed to fly out of the atmosphere into space.

#19 Re: Human missions » NASA's Moon Mission » 2005-09-18 10:49:29

There is only one thing I don't quite like about the NASA moon architecture. I don't like that two astronauts are left in orbit while the other 4 go down to the moon. I would rather 5 astronauts go down to the moon and the vehicle orbit the moon autonomously then 2 stay in orbit and a  4 go down to the moon.

Everything I've read is that four astronauts will fly to the moon in the CEV, and all four will land on the moon.  The CEV will orbit unmanned until it's time for the LSAM to lift off.

The Lockheed design that we've seen in public is a clunker, but I suspect that it's not the final form the design will take.  If anything, it might be a leak aimed at making Boeing-NorthGrum feel too cozy with their capsule design.  NASA clearly wants a capsule, so Lockheed's offer is unacceptable as-is.  But we may see the forward section of their CEV proposed as their final entry.  Personally, I liked their "circumcised Gemini" capsule a lot more than I liked the current "lifting monstrosity."

As far as pork in the CEV program, there will be ample opportunity for that.  Politicians always find a way.  The retention of the shuttle army (instead of a genuine effort at automation, on the scale of Delta IV and Atlas V) is the first pork chop being thrown to central Florida.  More will certainly come.

#20 Re: Single Stage To Orbit » Realistic solutions to the difficulties of SSTO? » 2005-09-18 10:28:05

Jeff Bell had a fun time knocking the DC-X, X-30, and X-33 as technically-unrealistic excuses to make the Soviets spend more money.  What he ignores is that some really smart people got behind these ideas at some point, which is why they got as far as they did.

In the famous case of DC-X, the idea had the support of Max Hunter (designer of the Thor missile and Lockheed Starclipper,) Jerry Pournelle (sci-fi author & pundit,) and the other members of the national space council.  In turn, the council convinced then-VP Dan Quayle that the idea of SSTO was worth pursuing.  Max Hunter and others believed that materials advances in the 1990's would allow SSTO to happen (even if it could orbit less payload than a TSTO of the same liftoff weight.)

DC-X was far too heavy to achieve SSTO, but it was never designed to demonstrate SSTO fuel fractions.  Its purpose was to lift off, hover, land, and do it again in short order.  A follow-on like DC-XC or DC-Y would demonstrate useful fuel fractions (at least according to the plan, before DC-XA tipped over and burned to the ground.)

X-30 also had the backing of serious engineers, because programs like Copper Canyon demonstrated the idea's basic feasibility.  Problems occurred only after the engineers took an in-depth look at the propulsion system and determined that it could only achieve Mach 12 in the atmosphere (even after employing active airframe cooling.)  The X-30's successor, X-43, was a remarkably successful and efficient way of testing the basic technologies that will hopefully bring scramjets closer to fruition.

As for Jeff Bell's contention that Aurora was merely an invention of Aviation Week to scare the Soviets, he's flying in the face of highly-respected aerospace analysts who believe that some kind of hypersonic prototype was built and flown.

For the X-33, the decisions of the engineers and managers are much harder to defend.  NASA really wanted an SSTO to replace the shuttle, so the proposals they received came across as disappointing.  Although McDonnell Douglas and Rockwell offered more potential, Lockheed was willing to kick in its own money to partially fund the X-33 and entirely fund the VentureStar.  Never mind the fact that there wasn't traceability between the Mach 15 X-33 and the orbital VentureStar.  NASA decided to bite Lockheed's financial carrot instead of cancelling the program like it should have.

#21 Re: Human missions » Shuttle ST-121 Atlantis » 2005-09-18 00:00:00

I think the whole idea of the INA is just foolish at this point.

Rep. Dana Rohrabacher has said as much during recent news coverage of NASA and the INA.  His point is that Russia has already given Iran everything it is willing to give regarding nuclear technology, so the INA no longer has any effect. 

It has to be asked whether Russia's technology transfers to Iran could potentially contribute to a nuclear bomb.  I'm certainly not defending Russia's actions, but I don't think the Russian-supplied reactors can be used to make plutonium for weapons.  Our biggest fear is that the centrifuges which enrich Iran's uranium (<3% enrichment for power plants, much higher for nuclear weapons) will be used to make weapons instead of reactor fuel.  Iran's centrifuge program can be traced to none other than Pakistan's Abdul Qadeer Khan.

I digress...

Right now NASA is in a fight for survival.  A law must be amended to keep the space station going.  Hurricane damage threatens the space shuttle program, and many workers are still unaccounted for.  Most frightening is the prospect that manned spaceflight could be scuttled altogether to pay for the broader hurricane rebuilding effort.  Just when we thought we were going back to the moon, we may be facing NASA's darkest hour.

#22 Re: Interplanetary transportation » Falcon 1 & Falcon 9 » 2005-09-10 01:24:15

GCN Revenger:
Jon Goff has the scoop on the Falcon upper-stage recovery method, plus some analysis on how it could work.

All:
As far as previous posts about the DARPA FALCON effort, I feel that I should clear up some misconceptions.  The DARPA and SpaceX efforts began around the same time, so neither can be accused of ripping the name off the other.  In DARPA's case, "FALCON" is a recent addition to the military tradition of forced acronyms.

The FALCON vehicle pictured in a recent post by SpaceNut is not a near-term vehicle, but an air-breather that will hopefully be the final result of FALCON's spiral development.  In the near term, FALCON demonstrators will be launched by rockets, and the Falcon I is a contender for FALCON launches.

#23 Re: Human missions » Shuttle ST-121 Atlantis » 2005-09-07 23:01:45

If the fixes are performed at KSC, and assuming the foam problems are indeed fixed, NASA can still make two or three flights in 2006 using the available ET's.  After that, it might be time to shut the program down if Michoud isn't fixed.  Why not shut it down now?  Because the FY 06 money's already been appropriated.  It also looks like the 16-flight ISS completion plan is in trouble already.

If we end the shuttle program on Sep. 30, 2006, that will at least allow NASA to fly a pair of ISS resupply flights, and Michael Griffin can get the Hubble mission he wants so badly.

#24 Re: Human missions » Shenzhou 6 » 2005-09-07 18:24:28

It's been almost two years since Shenzhou 5 made China the world's third spacefaring nation.  I haven't seen much recent press coverage about the followup, Shenzhou 6, but I'd expect it to launch within the next two months.

Perhaps the media blackout is associated with delays in the mission.  I wouldn't expect China's government to publicize the program's shortcomings if this scenario is true.

Delays or not, it's still taking a long time between Shenzhou launches.  China's manned spaceflight program is comparable to where Russia's was in the mid-late 1960's.  However, the slow pace of missions makes it hard to tell what the program's goals are.  Will China go for the moon?  Does it still want a space station to commemorate the 2008 Olympics? 

At this stage, Shenzhou looks like little more than a way of displaying China's national pride and technological prowess.  They need to toss some serious money and emphasis at this program, or it will resemble a flash in the pan.

#25 Re: Human missions » New Russian Spacecraft » 2005-09-07 18:13:09

The proposed Soyuz-3 sounds very interesting.  At this stage I can't tell if the NK-33 will go back into production (I think Kistler plans on using it for their vaporware launch vehicle.)  Even still, a new engine may produce more thrust, but without additional propellant it won't produce the right burnout velocity to put the spacecraft in orbit. 

The uprated engine is probably necessary to launch a heavier rocket with an added upper atege.  Could Soyuz-3 be the same as "Onega," the Soyuz with the hydrogen upper stage?

  1. Index
  2. » Search
  3. » Posts by Ad Astra

Board footer

Powered by FluxBB