Orbital Space Plane by 2008 - Faster, Cheaper, Better?

Ad Astra · 2003-09-11 22:50:12

The ideal design for OSP already exists; it was designed by McDonnell Douglas (now a part of Boeing) in 1967, and it was called "Big Gemini."

The Big Gemini was a lengthened Gemini capsule that could carry up to ten astronauts (if no cargo was carried.) It also had skids and a rogallo wing (which could be replaced today with the tested X-38 parafoil) so it could make runway landings. Best of all, the system was lightweight. As many folks have pointed out, OSP will cease to be either safe or economical if the heavy-lift variant of the EELV is used. But by keeping the mass low (i.e., Big Gemini or another capsule,) a single-core EELV can be used.

Like any solution, Big Gemini (or any capsule) has its drawbacks. In order to re-use a capsule, its thrusters and life support would need to be replaced between flights. Refurbishing the heat shield would also be difficult. The ablatve shield might be stripped off between flights (a la the X-15,) it could be given a thick ablative shield that was rated for a given number of re-uses (such as the re-flight of Gemini 2,) or tiles could be used. The tile solution would add many man-hours of time to inspect the shield, and adds a weight penalty. Look at how heavy Russia's re-usable Zarya capsule was, compared to Big Gemini. But because only a few capsules would be flown each year, it might make more sense just to build more instead of refurbishing them.

Ultimately, NASA will need a cheap, crew-only capsule and a true shuttle replacement that will haul big cargoes to and from the space station. Big G will fill the first niche nicely, and may even be used when mankind returns to the moon and ventures to Mars.

As to a shuttle replacement: the poor X-33 was doomed from the start because SSTO rockets are unforgiving when it comes to weight growth. Lock-Mart would have been better off if they stuck to the X-33's inspiration: Max Hunter's Starclipper. Although both ships were lifting bodies, the Starclipper and its successive designs carried most of their fuel in a cheap, expendable V-tank that fit around the nose of the vehicle like a collar.

RobertDyck · 2003-09-12 11:42:47

Ultimately, NASA will need a cheap, crew-only capsule and a true shuttle replacement that will haul big cargoes to and from the space station.

Why do you need to haul big cargos from the space station? You would need to return experiments, such as entire drawers from a science rack, but why anything bigger than that?

Ad Astra · 2003-09-12 17:09:28

The space station requires a lot of cargo to to come up and a lot of cargo to return to earth. Each Shuttle resupply mission brings 12.5 tonnes of water, rocket fuel, food, and scientific cargo. The European ATV (to fly in 2004) and Japan's planned HTV will carry roughly the same amount of cargo to the ISS (without a chance to return anything to earth, unlike the shuttle.) Further, the shuttle's OMS engines are used to re-boost the ISS. Although the same task can be done by Progress freighters, it makes fiscal sense to integrate this with the cargo mission.

Because the ISS currently lacks any vehicle that can deliver the 12.5 tonnes of cargo every three months, the crews have ben cut back to two. This will hopefully keep the ISS water budget balanced. But a shuttle or ATV will be necessay when the ISS crews grow to three and then to six.

The advantage of the shuttle (or a more durable replacement vehicle) over the ATV/HTV is the ability to RETURN cargo. ISS experiments are expensive. It also defeats the purpose of many experiments to let them burn up in the atmosphere when there. Many experiments, particularly those that deal with biology, must be returned to earth for future study.

There is really a need for three vehicles: a capsule to take humans to the ISS in the short term, and to be used on missions beyond the earth in the long term. A Starclipper-type vehicle must be built withinthe next ten or fifteen years to replace the shuttle. And a two-stage space plane with scramjets on the first stage can be developed within the next twenty to thirty years to deliver humans to more advanced space stations.

Algol · 2003-09-12 18:13:04

The OSP will have a small cargo carrying capability capable of taking experiments up and down. Also the ATV and HTV will boost the ISSs orbit whilst docked.

Spider-Man · 2003-09-13 00:16:07

I'd like to draw everyone's attention to Dr. Zubrin's recent article:

Convert the Shuttle
Robert Zubrin
It is now apparent that the Shuttle Orbiter cannot be used much longer as a system for transporting crews to Earth orbit. The Columbia disaster has made it clear that the antiquated Orbiters are becoming increasingly unsafe. Moreover, even if the Orbiter could be flown safely, it is clear that using a launch vehicle with a takeoff thrust matching that of a Saturn V to transport half a dozen people to the Space Station makes about as much sense as using an aircraft carrier to tow water skiers. The Shuttle was designed as a self-launching space station. Absent a permanent space station on-orbit, such a vehicle had some justification. But with the establishment of the ISS, the rationale for using a flying Winnebago as a space taxi is no longer sustainable.
NASA has already begun to respond to this reality by starting the Orbital Space Plane (OSP) program, which will move the human taxi-to-orbit function from the Shuttle to a small capsule or mini-orbiter that can be launched on top of an Atlas or Delta. If constrained to the objective of producing a simple reliable capsule instead of a complex mini shuttle, such a program makes a great deal of sense. A simple capsule will be much safer than a more complex system, will have a much lower development cost, and can be made available for flight much sooner, thereby cutting short the risks and costs associated with prolonged Shuttle operations. Launched aloft a medium lift expendable launch vehicle, it could assume the Shuttle's crew transfer function at less than 1/5th the cost.
As rational as such an approach might be, however, it poses a direct threat to the jobs of hundreds of thousands of people associated with the existing Shuttle program, and to the bottom line of several major and many minor aerospace companies. For this reason, some people have been lobbying for making the OSP a complex mini shuttle program that would take many years to complete, and cost, at most recent estimate, some $17 billion.
This is the wrong approach. The raid upon the treasury it involves would sap funding for any other space initiatives, and the delay it would entail in Shuttle replacement would expose our astronauts to serious unnecessary risk.
The right way to extend the Shuttle's industry's career is not by delaying the Orbiter's replacement. Rather it is to employ the simple capsule approach accelerate the transfer of taxi-mission responsibility, and use the funds saved to convert the Shuttle launch stack into something really worth having.
The reason why the Shuttle is such an inefficient launch system is precisely because it is dragging around the huge inert mass of the Orbiter. If we relieve the Shuttle launch system of that burden, however, and replace the Orbiter with a simple cargo compartment, we obtain the configuration known as Shuttle C, capable of lifting 70 tonnes to low Earth orbit. This compares quite handsomely with the current STS 20 tonne payload capability. However, we can do still better if we insert a hydrogen/oxygen upper stage into the payload fairing. In that case, we obtain the Shuttle Z, analyzed by NASA and the Martin Marietta company in the late 1980's, capable of launching 120 tonnes to Earth orbit or sending payloads in the 40 to 50 tonne class on direct trajectories to the Moon or Mars.
Such a Shuttle-derived Saturn-V class booster would provide NASA with the primary tool it needs to launch human missions of exploration throughout the inner solar system. However its development can only be justified if NASA actually initiates such a program. The space agency is thus presented with a choice; either embrace human exploration now, or be forced to throw away a $10 billion asset that will be needed if human exploration is ever to be done later.
If NASA makes the negative decision, and opts to discard the Shuttle infrastructure instead of converting it, the agency will be making a statement that it really never intends to do human exploration at any time. Under such conditions, the public will inevitably question, with considerable force of reason, what the remaining justification is for the Space Station, the OSP, and human spaceflight in general. The result will be an implosion of the entire manned space program. NASA is in a box, and the only way out is forward.
The Shuttle catastrophe needs to be answered not with retreat, but with advance. Human space flight will always be risky, but we need to be doing missions that are worthy of those risks. We don't need humans in space to study ant farms in zero gravity. We need humans in space to explore the planets. Converting the Shuttle will make that possible.
Dr. Robert Zubrin is president of the Mars Society (www.marssociety.org) and author of The Case for Mars: The Plan to Settle the Red Planet and Why We Must, published by Simon and Schuster.
To find out more about the Mars Society, visit our website at www.marssociety.org.

I happen to agree with him.

RobertDyck · 2003-09-13 08:26:39

Well, I agree with him but I don't. An OSP should be reusable; otherwise there is no point to building one. If you want an expendable capsule then just use the Russian Soyuz; it already exists and is well proven so it doesn't cost any development money. We have to actually work WITH our partners for the ISS. Notice his assumption is that any reusable OSP must cost $17 billion. I already argued that if properly managed it should cost between $1.2 and $1.7 billion. If the cost can't be kept down to that, then cancel the whole thing and use the Soyuz.

Yes, the Shuttle must be converted to an unmanned launch vehicle. However, the lift capacity of 70 tonnes was based on the old aluminium external tank, not the new aluminum-lithium super light weight tank. It also used just 2 SSMEs and kept the full cargo bay. I argue to keep 3 SSMEs and replace the cargo bay with a fairing. Let the cargo be supported directly by the engine thrust support structure, like a conventional ELV. The result was lift capacity of 104.7 tonnes to 185km orbit or 91.9 tonnes to ISS. That is without an upper stage. I included an ablative heat shield and parafoil so the engine pod could be recovered; so it would be about as reusable as the current shuttle. By the way, the current shuttle can lift 27.5 tonnes to 185km orbit or 16.05 tonnes to ISS.

Keeping with the theme of cooperation with ISS partners, lifting cargo to ISS can be done by the Russian Progress, European ATV, and Japanese HTV. Just work with Europe to ensure the ATV door can accommodate a science rack. I'm told that America changed the size of the science rack without asking the Europeans if it would fit through the door of their ATV.

Replacing the Shuttle can be done with a combination of an OSP or Soyuz with cargo vessels, and an ELV to lift modules. You would also need an on-orbit tug to grab a module where it is dropped-off by an ELV, rendezvous with ISS, and dock it. Such a tug could use a grappler hand like CanadArm/CanadArm2 but with a fixed mount (no arm). It could be remotely piloted from the ISS or mission control. The size should be about the same as the service module for Soyuz or Progress, so about 3 tonnes.

Spider-Man · 2003-09-13 12:36:30

Well, I agree with him but I don't. An OSP should be reusable; otherwise there is no point to building one.

His point is that you don't need an OSP, an Orbital Spaceplane, because it's useless and inefficient. All you need is a "Big Gemini" super capsule, something that can ferry crew and supplies.
There is no need for reusability.

If you want an expendable capsule then just use the Russian Soyuz; it already exists and is well proven so it doesn't cost any development money.

Besides not exactly being politically koscher (I can understand why NASA would want their own vehicle, and not to depend on the Russians for a darned thing), the Soyuz doesn't have adequate, or at least optimum, cargo capacity that Zubrin is putting forth, and nor does the OSP.

We have to actually work WITH our partners for the ISS.

Heh, work with our ISS partners, eh? Oh! you mean the European Space Agency? or the Russian Energia? Yeah, they sure keep up to their ends of the bargain...
They're the whole reason the atrocious ISS is hanging up their half completed to begin with, why we've wasted so much ungodly amounts of money keeping the thing going.
We could have cured cancer or something with the billions we lost on the ISS! That's being optimistic, though; we definitely would have had positive-feedback, self-sustaining nuclear fusion if the government put that kind of money into it.

Notice his assumption is that any reusable OSP must cost $17 billion.

The "ass" that is made out of both of us is in fact your own assumption that those are his figures. They are NASA's estimates, always being notoriously lower than what they end up to be.

I already argued that if properly managed it should cost between $1.2 and $1.7 billion.

Well NASA isn't capable of your thriftiness, my friend.

Yes, the Shuttle must be converted to an unmanned launch vehicle.

What? An unmanned launch vehicle? What the heck would that accomplish? The Shuttle infrastructure (the boosters, the tank, the engines) would best be served launching heavy cargo, like a trans-Martian habitat filled with supplies for three years.

However, the lift capacity of 70 tonnes was based on the old aluminium external tank, not the new aluminum-lithium super light weight tank.

The problem is all the massive, useless extremeties attached to the orbiter, including the wings, the heat shield tiles, the thrusters, all of it superheavy because it needs to be reusable. It's such a waste.

Replacing the Shuttle can be done with a combination of an OSP or Soyuz with cargo vessels, and an ELV to lift modules.

NASA wants their own, not some ancient Russian Soyuz. They also need greater capacity that the Soyuz cannot deliver.

You would also need an on-orbit tug to grab a module where it is dropped-off by an ELV, rendezvous with ISS, and dock it.

This is the inherent flaw. If the vehicle cannot do it on its own, it is useless. You're trying to prevent new technology from being developed, yet can you imagine the cost of testing such a monstrosity in space?

Such a tug could use a grappler hand like CanadArm/CanadArm2 but with a fixed mount (no arm). It could be remotely piloted from the ISS or mission control. The size should be about the same as the service module for Soyuz or Progress, so about 3 tonnes.

Too many problems; too much automation; too many things could go wrong. Let's stick with the Zubrin plan.

Ad Astra · 2003-09-13 16:15:22

I happen to agree with Robert here, regarding "Shuttle-C" or whatever you want to call this shuttle-derived cargo rocket. The only point where our ideas differ is that I don't favor mounting a clutch of space shuttle main engines in a reusable pod. I feel that the shuttle aft thrust structure should be slightly modified to house three RS-68 engines. This would give our SDV more thrust, and eliminate the hassle & cost of refurbishing the SSMEs.

A shuttle-derived EELV would keep the shuttle's "standing army" employed, and it would restore a heavy-lift capability that vanished with the demise of Saturn V and Energia. If such a vehicle had been available, a space station with all the capabilities of ISS could have been launched in one try (This was the "Option C" that NASA and Russia discussed in 1993.) If this SDV could be upgraded to Saturn V-like levels of performance (through a laterally-mounted upper stage and longer SRBs,) a twelve-person, nuclear powered space station could have been launched (as von Braun and his supporters planned for the late 1970's.)

As far as reusability goes, the capsule might be cheaper if it's expendable. As long as it's more capable and reliable than Soyuz (more than three crew, no 9g ballistic re-entries,) it will be worth the cost. If reusablity is a key to the success of OSP, a lifting body becomes more viable because of its benign thermal profile. Even though the baseline HL-20 is too heavy to be launched on a single-core EELV, bear in mind that the baseline HL-20 was designed around a crew of two pilots+eight passengers. Scaling this back to two pilots + four passengers would allow the designers to scale the vehicle down and reduce the amount of thruster propellant and consumables.

RobertDyck · 2003-09-13 23:24:22

Perhaps I should clarify. The Shuttle-C did not have an orbiter. It was the shuttle external tank, SRBs, main engines, Orbital Manoeuvring System (OMS), Reaction Control System (RCS), and cargo bay. There was to be no wings, tail, landing gear, heat shield, cockpit, or any support for human flight. The orbiter for most configurations of Shuttle-C would be expendable. One configuration did call for replacing the cargo bay with just a fairing and mounting the cargo directly onto the thrust support structure. I am saying we should use that. There was also a couple configurations that included a recoverable engine pod. I am saying we should also do that. There are a couple reasons for making it recoverable:
1) it would reduce operational cost because you wouldn't have to replace the engines with every flight.
2) NASA wants a reusable system, so arguing for something reusable is what NASA wants to hear. If you argue against them you will not even be heard.

This also fits with what Robert Zubrin is currently saying. He wants to convert Shuttle into Shuttle-Z. That is his configuration that used an expendable engine pod and an upper stage. An upper stage could always be added later. A reusable engine pod could get NASA to actually build it, so we only need to add the upper stage to become Shuttle-Z. I think Shuttle-Z also had 5 main engines, but Shuttle-C would be a strong step toward what we need to go to Mars.

Actually, NASA isn't saying it will take $17 billion to build OSP; the contractors are. I am saying that if NASA can build X-38 including 2 flight units for $1.2 billion, then with the work that has already been done they should be able to build an X-38 based OSP for less than $1.2 billion. If it takes a little more to get the OSP and ELV system aerodynamically balanced to be safe, then it is worth it. But $17 billion is ridiculous. If developing a reusable system does require that much up-front cost, then an expendable capsule would be worth it. However, why should we pay a single cent for an expendable capsule when the Soyuz is already available?

Developing something new is a good idea if it has value and doesn't already exist. If that thing does already exist, then it is just stupid to waste money to reinvent it.

Spider-Man · 2003-09-13 23:43:38

I agree with virtually everything you said, but...

However, why should we pay a single cent for an expendable capsule when the Soyuz is already available?
Developing something new is a good idea if it has value and doesn't already exist. If that thing does already exist, then it is just stupid to waste money to reinvent it.

But it doesn't already exist. Ad Astra noted some of the major flaws with the Soyuz, including a limited crew of no more than three, limited cargo space inside for supplies and perishables, and those godawful reentries, at accelerations that are unbearable and in directions that are hard to control. Heck, being able to pick a specific splashdown location in the ocean alone would reduce costs, mainly in fuel expendature for aircraft carriers and other ships and helecopters which would have to retrieve the capsule.

It would save money in the long run, being able to do more and waste less than a Soyuz. Besides, nothing in space travel will be advanced by using something so archaically old when many better accomodations can be made.

RobertDyck · 2003-09-14 09:03:30

But it doesn't already exist. Ad Astra noted some of the major flaws with the Soyuz, including a limited crew of no more than three, limited cargo space inside for supplies and perishables, and those godawful reentries, at accelerations that are unbearable and in directions that are hard to control. Heck, being able to pick a specific splashdown location in the ocean alone would reduce costs, mainly in fuel expendature for aircraft carriers and other ships and helecopters which would have to retrieve the capsule.
It would save money in the long run, being able to do more and waste less than a Soyuz. Besides, nothing in space travel will be advanced by using something so archaically old when many better accomodations can be made.

Don't fall into the political trap of saying that everything American is good, everything Russian is crap. Reality is that the acceleration of Soyuz is the same as Apollo or Gemini. The astronauts who returned on Soyuz have never returned via Apollo so they don't know what Apollo felt like; they're spoiled by the low acceleration of Shuttle. If America builds an expendable capsule, expect the same high acceleration. Apollo's entry wasn't any better controlled than Soyuz; the navy had to send helicopters from an aircraft carrier to find an Apollo capsule. That wasn't any easier to find than a Soyuz capsule on the steppes of Kazakhstan. Apollo never was able to pick a specific splashdown location closer than "somewhere in the south Pacific". The cost of the aircraft carrier, other ships and helicopters is one reason I argued for an X-38 based vehicle. To recover that you would only need a flat bed medium truck with dual rear axle and a truck crane, together with the current shuttle vehicle to drain propellants from the OMS and RCS tanks, and a van to carry astronauts. You could also send a Hummer with marines to guard the astronauts, and an ambulance. All that is cheaper than an aircraft carrier group.

Since construction of ISS, the only capsule they had difficulty hitting the target zone was the first flight of Soyuz-TMA. Has America never had a setback with the first flight of a new vehicle?

Ad Astra · 2003-09-14 10:29:04

The 9g deceleration and the off-course landing of Soyuz TMA-1 was due to a control problem. If the systems would have worked correctly, the Soyuz would have instead made a more manageable, 4g lifting re-entry. No capsule is immune to this problem; but its occurence on the Soyuz flight indicates a quality control issue.

It would be a fallacy for us to say that we don't need two capsules, and I'm certainly not saying that an American spacecraft would be better by default. What I am saying is that Soyuz is an old design that, despite the upgrades, was still configured for circumlunar flight and Salyut/Mir missions. A Big Gemini, with three times the crew of Soyuz, is better suited for the larger crews that ISS could handle in the future. Further, Big Gemini could be steered to a pinpoint landing at an airstrip and not require a recovery at sea or in the Russian wilderness

Spider-Man · 2003-09-14 11:53:48

The point is simply this:

NASA will never, ever, ever, ever use a Russian anything to do any primary LEO maneuver as its primary spacecraft ? never! Call them stoggy, call them arrogant, call them foolish for overlooking what, you claim, is a perfect, ideal, ready-made space capsule (I do not concur, and I doubt they would either given their expectations), but that is most certainly what they would choose. They want their own design, if for pride alone. May they choke on such hubris.

Ad Astra · 2003-09-14 12:50:15

NASA isn't totally unwilling to use hardware that isn't made in the USA. The HL-20 was a refinement of Russia's BOR-4 lifting body. The core modules for ISS were designed for Mir-2. NASA's America-first mentality comes into play when it means preserving the jobs and the technical base of America's aerospace industry. Needless to say, Congress would rather spend money on creating manufacturing jobs in the US before they spend money on creating Russian or European or Japanese jobs.

RobertDyck · 2003-09-15 17:07:19

Congress read Robert Zubrin's article into the congressional record. Out of the hope they are reading this thread, I'll add this little bit of advice. Develop new technology when you don't have a pressing need for it. When your suppliers realize you have to purchase the product, and do so as soon as possible, they will increase the price. The X-38 was developed at a time when there was no urgent need for it; the Russian Soyuz could do the job. The budget was $1.2 billion. Now after the Columbia accident there is an urgent need for a Shuttle replacement. Although an adaptation of X-38 could do the job, the cost has risen to over 10 times that price. At this time there is no urgent need for a heavy lift launch vehicle larger than Delta IV Large; therefore now is the time to develop one. Develop Shuttle-C now and the cost will be low; wait until there is an urgent need for a truly heavy lift launch vehicle and the cost will sky-rocket (pun intended). You can argue whether the engine pod should be recoverable or expendable, but either way a Shuttle Derived Vehicle should be developed now while it's inexpensive.

alokmohan · 2003-09-16 04:03:06

Should the OSP be of any help?does anyone foresee its doom right now?Should NASA proceed?Is there any chance of accident?Will somebody enlighten?

RobertDyck · 2003-09-16 07:41:42

Of course the OSP could be of help. A small and inexpensive Orbital Space Plane designed to carry just astronauts to the International Space Station could provide safe access to space at a reduced price. Since it will be placed on top of an Expendable Launch Vehicle there is no chance of ice or a chunk of ice filled foam breaking off and hitting the heat shield tiles. Since the ELV will not use segmented solid rocket boosters there is no chance of an O-ring failure releasing flaming exhaust into a cryogenic hydrogen tank. So the accidents that caused the failure of Columbia and Challenger could not happen with OSP. A sloppy design could cause a new failure, so the engineers must be careful what they design. Should NASA proceed? Will OSP be doomed? At a development price of $17 billion dollars it appears to defeat the purpose of reducing the cost of access to space. Media news releases and video anamations of OSP proposals keep using the Delta IV Large or Atlas V 551 to launch it. Both of those vehicles cost $170 million per launch in 1998 or 1999 dollars. That again appears to defeat the point. People keep talking about how expensive the Shuttle is to operate, but much of that is maintaining the Kennedy Space Center, Johnson Space Center, etc. The cost per launch of Shuttle in 1988 was $245 million if you include the cost of all space centers and spread it over only 6 launches per year. The actual cost per launch if you don't include the "overhead" was just $63 million. Today the costs for Shuttle have doubled, but it still raises the question of whether OSP will be any cheaper if you use the largest ELV available. Astronaut training and mission control will be needed no matter which vehicle you choose, so the Johnson Space Center must be maintained; you won't save a dime there. This is one reason I argued to size the OSP for an EELV with a single common core booster and no solid rockets. The Atlas V 401 cost $77 million per launch in 1998 dollars. There is no price for Delta IV Medium with the Delta 4H-2 upper stage, but the Delta IV Medium with the smaller Delta 4-2 upper stage and two GEM 60 solid rockets cost $95 million in 1999 so eliminating the solid rockets and using the larger upper stage should cost about the same.

As for the extreme development cost that the contractors are now asking... That may kill the program.

dickbill · 2003-09-16 12:05:45

Congress read Robert Zubrin's article into the congressional record.

I have read the article in the Mars Society frontpage, about what said Zubrin on the scientific experiments on the ISS ("we don't need the ISS to breed salamanders in zero gravity") I completely agree.
A scientist, still lucky enough to have an experiment aboard the ISS, has said basically the same thing in the New York Times recently: that an automated satellite would have done as good and for much cheaper. And if you don't believe me, OK, launch a search in PUBMED (a scientific database) at http://www.ncbi.nlm.nih.gov/

Insert MIR or ISS into the keywords. For example I used "MIR space station" as a search and got 366 references. "ISS International space station" gives 123 references. This is not an accurate and fair mesurement because any abstract, even a review, quoting the ISS will be included. But still, it's a base of comparison, now it would be interesting to study each of these references and gives them an "Impact Factor" of relevancy or interest, subjective somewhat, but if done seriously, it would allow to quantify the amount and quality of science actually done in the ISS.
Financial data on the costs, direct or indirect, would then show how the ISS compete with MIR, Skylabs or other automated Soyouz, per unit of Impact Factor.

Josh Cryer · 2003-09-16 13:20:58

Lots of sensiblity in this thread. I agree with Robert.

Algol · 2003-09-16 13:39:41

PUBMED refers only to medical experiments. Whilts i agree with you in this specific area the materials science conducted on the ISS cant readily be done by automated satelites and really requires hands on scientists to be there. Im sure there are plenty of scientists working in a range of fields who would say the same.

There are experiments, in a range of fields, that do need to be conducted by scientists. That said, the ISS is not turning out to be the most cost effective way of doing them.

Bill White · 2003-09-16 15:17:09

IMHO - - this article - - in two parts renders the OSP debate moot.

Can any of the more technically inclined challenge the arguments made in this article that space planes are inherently impractical?

So America's new spaceship will look like this (from top to bottom):
A Launch Escape Tower for aborts on the pad or during the high-q portion of ascent.
A Return Module with the shape and center-of-gravity of the Apollo CM, but lighter since thermal protection will be scaled down for the orbital mission. One attractive configuration would be a Mercury-style detachable ablative shield on the bottom and reusable hot-structure on the sides. Electronics and life support will use modern technology, and the cabin walls must be strengthened to hold in the standard ISS atmosphere. A version of the RM with simplified long-life systems and a small solid-fuel retrorocket will serve as the ISS lifeboat.
A Propulsion Module with thrusters and a variable number of hydrazine/NTO fuel tanks. Fuel weight can be traded off against supply weight depending on the current needs of ISS. The propulsion system will provide 1) abort capability after the escape tower is jettisoned; 2) orbital circularization and automatic rendezvous with ISS; 3) reboost of the ISS; 4) insertion into the reentry trajectory. The PM could also carry most of the expendables needed to support the RM up to reentry.
A Supply Module loaded with cargo for the ISS. This will be a simple pressurized can attached to the bottom of the PM. This module will be docked separately to the ISS (either by the RM/PM or by the Canadian robot arm on the ISS) and gradually emptied of supplies. The SM from the previous flight, now loaded with refuse, will be attached in its place and burn up along with the PM when the Reentry Module enters the atmosphere. Possibly two models of the SM could be designed, one for Delta 4H and one for Atlas 5H. This would allow missions to use both boosters for improved flexibility and competition.

dicktice · 2003-09-16 17:39:16

Well--reluctantly--what else can the U.S. do (being so not-invented-here) but play catch-up to the Russians, this way? A better plan would be to adapt the Energia, etc. hardware and work with them in the interim, while going all-out to produce a really good modular "spaceplane" system. I still would like to propose a stratovolcano maglev launch ramp, using railcar switch-yards at the base of (say) Kilimanjaro as the way of the future.

RobertDyck · 2003-09-16 17:52:13

Lifting body trade-off between blunt reentry shape and streamlined: the X-38 used a very blunt lifting body with very small airfoils, and it used a parachute to land. The slow parachute landing the author wanted is there with X-38. The temperature problems with pressurized tires are also eliminated by the landing skids of X-38. The skids are very narrow; they can be made of titanium which can withstand the heat, so the skids are located outside the heat shield. You only need holes in the heat shield large enough for the support struts to slide through.

Lifting body heavier than a capsule: true, but a capsule is expendable, a lifting body can be reused. How many launches does it take for a reusable spacecraft to have a lower total cost vs. an expandable?

All those flaps and hydraulics do make the vehicle heavier, but the alternatives are rockets to control descent (even heavier than the flaps and hydraulics), or an uncontrolled descent. An uncontrolled descent requires an ocean to land in, so that requires ships and search helicopters to find it. A controlled landing on ground requires fewer and less expensive support vehicles. The skids with shock-mount struts eliminate the need for landing rockets that Soyuz uses, or buoyancy devices of Apollo.

Booster incompatibility: less of a problem with a lifting body than wings.

Seat configuration: with a nose-up orientation, how much forward acceleration does the crew experience. Isn?t it mostly down? You could recline the seats for reentry.

Forward window inefficient: use a video camera and LCD display for a virtual cockpit. You probably still want a small window for psychological reasons, but that can be placed on the top near the back where there is least heating.

Political difficulty buying ATVs from the same production line supplying ESA: Suck it up. America has a lot of other space vehicles to build; let Europe have this one.

Combining a supply module with manned transport: bad idea. You want to separate crew from cargo so your cargo ship can use solid rockets, high acceleration, reduced redundancy, and no abort capability. If one in a hundred cargo missions fail on a vehicle that costs 1/10th the price, it is still cost effective. You can?t do that with a manned vehicle.

Propulsion module used to reboost ISS: do you want to do that? That is a function of the cargo ships: Progress, ATV, HTV. Why do you want to put another cargo function in the manned spacecraft? The same for placing expendables in the propulsion module.

X-38 used an expendable propulsion module. You probably want OSP to incorporate propulsion capability into the space plane so that it is reusable. HL-20 did that. Avoid throwing stuff away, it costs money.

Political inability to stop launches from KSC: convert Shuttle to a truly heavy lift unmanned launch vehicle. The low cost per pound to orbit could make an orbital hotel viable, asteroid mining, etc. Of course this could be the launch vehicle for a manned mission to Mars. Develop the Shuttle Derived Vehicle now, keep development cost low, maintain the existing workforce.

dickbill · 2003-09-16 17:53:32

PUBMED refers only to medical experiments.

Not only medical, also biology, exobiology and wide range of bio-sciences are included, but, I agree that many physic and chemistry experiments are not recorded in that database.

There are experiments, in a range of fields, that do need to be conducted by scientists. That said, the ISS is not turning out to be the most cost effective way of doing them.

Not the most cost effective ? that is sure. But If the ISS is not a scientific platform, what is it ? Right now, It has nothing else than a scientific purpose. In the future, maybe the ISS will found new usage ( like a base for space exploration ), let's hope that.
But frankly, the ISS managers have been lucky, what would have happened if the russians could not have sent cargo vessels to resupply after the shuttle disaster ?

Algol · 2003-09-16 20:53:47

ISS is the only and as such most practical platfrom for conducting the experiments that need to be done. We can bitch about it as much as we like, and we'd be right too, but its there, and it'll get the job done, eventually.

Anyway, the real reason im posting, i just read this article. So depresing; if this is true then im just gonna curl up into a ball and give up on NASA all together......

Space shuttles to last into next decade - Boeing

"There is not right now on the drawing board one vehicle that can replace what the shuttle can do,"

Have they learnt NOTHING!

Since the International Space Station was designed to work with the space shuttle and to stay in service until at least 2018, the shuttle should probably stay in service until that date, Mott said.
"So if you go to 2018 that becomes very logical because that (the shuttle and the space station) works together as an integrated system," Mott said

*Curles up into a ball* <sigh>

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