OSP or air-launched vehicle? - Tell me what you think!

nirgal · 2003-02-16 10:55:45

What do you think about NASA's plans for an orbital spaceplane launched on top of an EELV? After reading this analysis by Markus Lindroos I think an air-launched vehicle would be a better idea.
Your input is appreciated.

soph · 2003-02-16 11:01:42

Well, like I've said, I like an NTR SSTO approach better, but I think that air-launch is a good approach, because you don't need the immense infrastructure, and it saves money on equipment. Besides, its basically completely reusable.

dicktice · 2003-02-16 11:37:57

Amazingly, the more the discussion, the closer we seem to be approaching Arthur C. Clark's system in his novel "Prelude to Space"! Anyone remember that one? It's still a good read.

RobertDyck · 2003-02-16 12:35:52

Spaceplane on EELV would be a good improvement over the current shuttle. An NTR SSTO would be better, especially if you included a nuclear ramjet during atmospheric ascent to reduce propellant, but you still have to convince the public there won't be radioactive exhaust. After Columbia the public will be worried about catastrophic failure. You could launch over an ocean, but re-entry would be over land. What happens if the heat shield fails again and nuclear fuel rods from a reactor that has operated fall out of the sky? It may be a good idea to focus on more reliable re-entry systems and worry about a better launch system later. That means an orbital spaceplane on an EELV and a Russian MAKS. We can also focus on nuclear reactors for nuclear electric propulsion. Ideally while all of this is going on, the nuclear guys would work on a safe and functional liquid core NTR engine and uranium nuclear ramjet engine with sealed fuel elements. The engines could be used on some future SSTO RLV.

The VentureStar and X-33 were to have metallic heat shields. I heard that it was supposed to be more durable but would provide less heat protection, requiring a shallower angle of re-entry, and the re-entry angle dictates the aerodynamics. Does anyone have more information about this or other heat shields?

Ad Astra · 2003-02-17 09:13:00

Air launch for an RLV eliminates the need for new launch pads, but it poses additional problems. For one, a spaceplane will always be heavier than a rocket because it must be designed to resist bending loads from pitching maneuvers. And the fuel expended during the pitch-up maneuver negates the fuel savings of a subsonic carrier aircraft. This can be remedied if you used an airplane like a B-1 or TU-160 with a lot of thrust to release the RLV on a "toss-bombing" trajectory. But the carrier aircraft must also have room for additional fuel to replace the propellants that boil off inside the RLV.

This being said, I still support the development of an air-launched RLV. But I think that OSP will be developed faster if the designers stick with a lifting body mounted to an ELV, or perhaps a two-stage RLV system with a booster similar to the Kistler K-1.

Ad Astra · 2003-02-19 12:02:11

NASA came out with specs for the OSP today and they'r a bit underwhelming. I'm particularly disappointed that the vehicle is only required to have a crew of four (In the Orbital Sciences concept, there are two pilots and three astronauts, leaving little chance of a six-man ISS.)

I expect OSP to resemble a lifting body (such as the HL-20 being promoted by Orbital) or a delta-wing glider like Hermes or the Dyna-Soar. I doubt that air launch will be considered for OSP, but it might be a possibility for the "shuttle successor" that will come around in 2020.

John Pike has some fairly encouraging things to say about the economics of OSP on www.Globalsecurity.org.

RobertDyck · 2003-02-19 13:23:03

I support the OSP. A 4-crew vehicle would be an excellent addition to the ISS. Remember, the European Space Agency is working with Russia to maintain Soyuz. With both a Soyuz capsule and a 4 astronaut OSP that provides a total crew compliment of 7; which is the original design for ISS. Furthermore, a well designed 4-astronaut OSP could be launched on an Atlas V 401 at a cost of $77 million per launch for the rocket. A reasonable estimate for a 7-astronaut OSP would be the last design for X-38 with its de-orbit module, which would require a Delta V Large to lift it at a cost of $170 million for the rocket. A 4-crew OSP would be a very economical design. Furthermore, a vehicle designed to carry just 4 astronauts and no cargo at all could have 1-3 seats removed and replaced with duffle bags to carry cargo. That would fulfill the cargo requirement.

soph · 2003-02-19 14:46:48

So basically, what we're getting is a crew ferry, and nothing more?

Which kind of makes sense. The ISS can take over the science aspect of the Shuttle entirely.

So now let's take a look at our space program. Can expendable boosters be used to launch things like orbital labs, economically?

Can these labs then be serviced and crewed using OSP's?

Can we drive down the cost of the OSP over time? Would mass production drive down the cost?

Ad Astra · 2003-02-19 15:54:59

I always thought that the goal of OSP was to replace the various crew-transfer craft like Shuttle and Soyuz with a safe, inexpensive and reusable vehicle. It doesn't make sense to launch both a Soyuz and a lightweight OSP when both launches can be combined into a single, heavyweight OSP launched by a heavy EELV.

And if NASA is unwilling to commit to a six-man, scientific space station, we should fund neither ISS nor OSP. ISS has cost far more than we expected, and its science return is smaller than expected due to cutbacks in crew and habitable volume. The taxpayers are being asked to front the costs for OSP because it should remedy the situation. But if NASA wants to stay with such a minimalist station, they should forget about it and quit wasting money on this boondoggle.

soph · 2003-02-19 16:56:51

Actually, the minimum requirement for the OSP is 4 crew members. This is strictly a minimum. The OSP will be designed, I believe, around a Delta IV booster, which means a 7 person OSP is probably going to be built. This means that we aren't going to have any science equipment, shorter missions, and cheaper missions.

Which is fine, because that's what the ISS is there for: the long-duration science missions. There's no reason our shuttle should be doing science missions when we have the ISS.

So, I am very happy with how the OSP is looking. It is being approached the right way: as a crew ferry, and not a flying space station. Perhaps these cheaper launch possibilities will allow further orbital development by private companies, via expendable boosters, and serviced and crewed by OSPs.

nebob2 · 2003-02-19 18:11:32

I see no reason why the same airframe could not be adapted to both a pure crew transport and a Progress-like automated cargo/supply ship. By seperating the two, the overall design is simplified.

RobertDyck · 2003-02-20 01:25:45

Remember that the Atlas V 401 in 1998 dollars has a launch cost of $77 million. The Delta IV Large costs $170 per launch in 1999 dollars. If you can launch two 4-crew OSP vehicles for $154 million plus OSP processing and mission control, as apposed to one 7-crew OSP vehicle for $170 million plus the same OSP processing and mission control costs, then which is better? Let's see: 8 astronauts for $154 million vs 7 astronauts for $170 million. Even if the bottom line cost were the same, then the smaller vehicle gives you the flexibility of sending just a small crew, or rotating just 4 astronauts at a time.

By the way, NASA may want a completely independent crew transport capability, but Europe and Russia may want something else. In fact, Europe and Russia both want a transport capability completely independent of the United States. That is why ESA is talking about launching Soyuz spacecraft from Kourou. (SpaceDaily)

Ad Astra · 2003-02-20 08:18:35

It's also possible that ESA will buy into OSP and launch it with the Ariane 5 booster. And even assuming that two small OSPs could be launched cheaper than one, I don't think NASA likes the idea of tying up both docking ports with rescue spacecraft.

I don't think that OSP is the answer for replacing Progress freighters. A vehicle like the Kistler K1 would be best, assuming Kistler can get the funding and begin testing. I see the Kistler vehicle as a progressive step towards full reusability and routine space access.

RobertDyck · 2003-02-20 11:15:06

There are 3 U.S. supplied pressurized mating adapters in the final configuration, one that connects the Zarya to Unity, the other 2 are docking ports. Those are just the U.S. docking ports, the Russian part of the ISS has 2 more: one at the end of Zvezda (intended for a Progress cargo craft), and the other on a Docking and Stowage module that is connected to Zarya. The last module is the docking port for Soyuz spacecraft, which will replace the current Docking Compartment. I don't know if the Docking Compartment can be used as a 5th docking port once it is moved to the Universal Docking Module. The bottom line is that 2 OSPs and a cargo craft are well provided for.

By the way, the European Space Agency had made a big deal at one point of developing a cargo craft to be launched on an Ariane 5 rocket. I assume they're still working on it.

soph · 2003-02-20 12:17:10

I don't think the OSP is intended to be used as a cargo craft, I think it's designed to be a crew ferry. I would like to see it used in conjunction with the Progress, or even a NASA-developed unmanned cargo craft similar to the Progress.

I have heard rumors that NASA may be developing two different spacecraft-a crew ferry and a cargo ferry. I sure hope so! We could actually use the right craft for the job needed, saving money. We don't have to kill an ant with a tank.

RobertDyck · 2003-02-22 00:50:09

I found some information on Thermal Protection Systems. The Shuttle uses a combination of systems; the grey areas on the tip of the nose and leading edges of the wings are reinforced carbon-carbon. These can withstand 2960?F heat and are extremely durable, but heavy. The black tiles are LI-900, also know as Reusable Surface Insulation or RSI tiles. They can withstand a maximum of 2300?F, but they are silica fiber foam coated with black glass glazing and glued to Nomex felt which is glued to the aluminum skin. White tiles have a white glass glazing and can withstand up to 1200?F. Low temperature upper areas have quartz fiber quilts for up to 1500?F, or elastomer (plastic) coated Nomex felt for up to 750?F.

The super alloy honeycomb (SA/HC) metallic Thermal Protection System (TPS) intended for X-33 was an Inconel metal honeycomb sandwich top plate held away from the skin with titanium stand-offs, and a folded foil bag of insulation. Inconel is a nickel alloy: 44.5% nickel, 20-24% chromium, 10-15% cobalt, 8-10% molybdenum, 3% iron, and some trace metals. It is heavy and its melting temperature is lower than titanium, but it retains its strength at high temperature. SA/HC metallic TPS tiles made with Inconel have a maximum operational temperature of 2000?F.

The Advanced Metallic Honeycomb (AMHC) thermal protection system uses PM2000 metal honeycomb sandwich top plate and Internal Multiscreen Insulation (IMI) with a thin titanium facesheet on the bottom. PM2000 is a form of stainless steel called Oxide Dispersion-Strengthened (ODS) alloy: 73.5% iron, 20% chromium, 5.5% aluminum, 0.5% titanium, 0.5% Y2O3 (yttrium oxide). AMHC tiles have a maximum operational temperature of 2200?F.

AMHC can operate almost as high as the black silica tiles on Shuttle. This permits reasonable operation and safety during re-entry. The greater durability of a stainless steel outer skin that is attached with metal fasteners rather than fragile silica fiber foam glued on felt means the heat shield will stay on. LI-900 tiles are typically 6"x6" in size, and AMHC was designed for 12"x12" tiles. However, I feel large panels would be far safer and more economical. Each gap between tiles is a potential entry point for hot plasma, and potential breaking point to lose a tile. Small tiles would only have one Allen screw or boss with quick release spring at each corner. A large panel could have multiple fasteners over its surface. If one fastener breaks loose on a large panel the remaining fasteners can keep it in place. Furthermore, each AMHC tile require a PM2000 side wall and a strip of Nomex felt between the tile and aluminum skin at the tile edges. Large panels reduce the number of edges, therefore reduce the quantity of sidewalls and felt strips; this reduces weight. Don't you love it when a weight reduction increases safety? Large panels also mean fewer panels to manufacture and install, so less labour which translates to lower cost.

Ad Astra · 2003-02-22 06:31:08

It's too early to say whether the fragile nature of Columbia's heat shielding caused its destruction, but I do agree that an alternative to these various ceramic tiles must be found. Boeing's been talking about composite heat shields for their X-37, but I have to say that metallic heat shields make the most sense (unless somebody comes up with an ablative paint that can be easily stripped between flights.)

Returning back to the original topic of the thread, air-launched RLVs, there is one significant problem that has to be worked out. Someone needs to find a means to shift the CG from a boost position to an aftward glide position. This is not a problem with the baseline MAKS because the propellant mass is stored in a front-mounted expendable tank. But the fully re-usable Maks-M will undoubtedly have issues with this, as have all totally-reusable vehicle designs.

RobertDyck · 2003-02-22 10:22:22

MAKS-OS is capable of lifting 7.0 tonnes in its basic manned configuration to an altitude of 400km at an inclination of 51?. It is able to lift 8.2 tonnes to the same orbit if unmanned. The manned configuration has a 2-seat cockpit and no docking unit. MAKS-OS/TMS-1 has a docking unit and pressurized module with 4 more seats. MAKS-OS/TMS-2 has the docking unit but the remainder of the cargo bay empty for cargo; useful for re-supply missions, it can carry 3.6 tonnes.

MAKS-M can only carry 3.5 tonnes to the same orbit, and that is with no crew capability at all. The significantly reduced cargo capacity and inability to carry crew make it appear much less valuable than MAKS-OS. You have to look at the cost per tonne to orbit. Two flights of MAKS-M are required to match the lift capability of MAKS-OS, so would saving an expendable external tank reduce cost by as much as the total for a second launch?

In fact, for cargo you should look at the MAKS-T. Replacing the reusable orbiter with an entirely expendable second stage lifts 17.4 tonnes of payload to the same orbit. Disposing of engines, avionics, etc, would increase the per launch cost, but would the increased lift capacity be worth it? What matters is the cost per tonne to orbit.

Ad Astra · 2003-02-22 20:14:55

The info I got from Encyclopedia Astronautica indicates an 8.3 tonne payload to a 200 km orbit for the baseline MAKS. This payload weight would include a docking mechanism, so your payload delivered to ISS would be lower, but flying the orbiter unmanned would increase that payload to 9.5 tonnes.

Subsonic air launch gives MAKS a delta-V of about 270 m/s, but it also allows the spaceplane to reach all sorts of orbits and spares the expense of fixed launch sites. Clearly, air launch has tremendous benefits over ground launching once the technique is perfected.

MAKS was a promising development that was disappointingly killed by the Russian economic crisis. In reality, it should have been developed in place of the Buran, which was bound to inherit many of the problems that plagued the American Shuttles. Because much of its enabling technologies had been developed for Buran, the only big question mark was the tri-propellant engines.

Hopefully the money to revive MAKS will come, from either the space tourism business, or from NASA / ESA. It might need to be redesigned to use conventional bipropellant engines. But the basic design philosphy is sound, and MAKS could provide ISS with a low-cost, highly-flexible replacement for the Shuttle (on crew transfer flights) and Progress (on resupply missions.)

RobertDyck · 2003-02-22 21:23:07

I am looking at the Molniya web site, the Russian manufacturer of the MAKS. The MAKS English page is here. The paper I am quoting from is "The MAKS Multipurpose Aerospace System" by Skorodelov V.A. here.

Ad Astra · 2003-02-23 00:43:29

Marcus Lindroos has a scathing review of the economics of OSP.

With MAKS, the only recurring cost is the fuel and ET. High flight rates are possible with the spaceplane, which will negate its small payload.

What should NASA do about this? I have an idea, although NASA probably won't pursue it:

1) Solicit a proposal from Molniya (or Molniya partnered with a major American firm) for OSP and recommend that MAKS be used as a basis.

2) The MAKS-derived OSP will initially be launched unmanned as an ISS lifeboat.

3) Such an OSP will utilize a robust (metallic?) heat shield and existing or near-term engines.

4) Within three years of the unmanned OSP flight, the MAKS-derived OSP will begin airlaunch test flights.

nirgal · 2003-02-23 17:35:57

The Russians were no the only ones interested in air-launched vehicles. Check out these links:

Air-Launched Sortie Vehicle - design by Boeing

Air-Launched Sortie Vehicle - design by Rockwell International

RobertDyck · 2003-02-23 19:05:52

Marcus Lindroos has a scathing review of the economics of OSP.

Marcus Lindroos' criticisms of OSP are based on reduced cargo capacity. But why would you want to send cargo on a manned vehicle? Food and personal hygiene products are consumable, and waste can be de-orbited and burned up in an expended cargo vehicle. Cargo can be delivered via a high acceleration vehicle that is more propellant efficient but would turn astronauts into spam-in-a-can. Cargo does not require as much redundancy: if you have a loss rate of 1 vehicle in 50, while backup systems would improve survivability at a cost of say 25% reduction in cargo mass, then you would be better off letting the 1 in 50 vehicles be destroyed and simply replace it with another launch. You can't afford to do that with a manned vehicle. That means you are better off separating cargo from crew. Build the OSP to carry 4 astronauts and 1 suitcase of personal items each; that is all. Send food, water, spare parts, tools, scientific supplies, etc, on a separate cargo vessel. Keep EVA equipment on the space station.

If an entire equipment rack needs to be swapped out we still have the current space shuttle. No one said the shuttle is completely obsolete. We need a fleet of different vehicles for different purposes. A dedicated space taxi to transport crew will reduce cost and permit a greater number of crew rotations, and hopefully a greater number of crew at one time on the station. A dedicated expendable cargo vessel such as the Russian Progress will keep the station supplied at an affordable cost. New modules can be delivered via expendable rockets such as Proton, Angara 5, Atlas V 551, or Delta IV Large. The shuttle can be used for the rare times we need to swap an entire scientific rack, or use CanadArm for assembly or maintenance work that the station's CanadArm2 cannot reach.

soph · 2003-02-23 19:12:11

Agreed-keep cargo and crew separate, there's no need to send cargo on our crew vehicle. I would make the vehicle hold 7 people, however.

A capsule design might be the best for a supplemental cargo vehicle. It could even be reusable, let it splash down into water to be used again in another launch.

RobertDyck · 2003-02-23 19:27:49

Here are some statistics for you:

The final proposed configuration of X-38 would have used the same Thermal Protection System as the Shuttle, would have carried 7 astronauts and no cargo, and would have had a total mass including its expendable de-orbit module of 14 tonnes. That is 2 tonnes per astronaut. Soyuz-TM has a mass of 7.15 tonnes, includes 14 days of life support, has propellant for a total delta-V of 360 m/s, and carries 3 cosmonauts. That is 2.38 tonnes per cosmonaut.

This means a new OSP to carry 4 astronauts should have a total launch mass of 2 tonnes per astronaut. Expect it to fit within 8.25 tonnes including a small suitcase per astronaut. Airlines permit a carry-on bag to be 23cm x 40cm x 55cm (9"x15.75"x21.65") and mass 10kg (22 pounds). One such carry-on bag per astronaut would mass a total of 0.04 tonnes. I think this is quite reasonable. The Atlas V 401 can lift 8.25 tonnes to ISS.

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#1 2003-02-16 10:55:45

Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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Re: OSP or air-launched vehicle? - Tell me what you think!

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