| Technical Details | ||
| Payload (kg) | 100-500 700-1,000 |
|
| Range (km) | 3,500-4,300 (2-stages) 4,000-4,300 (3-stages) |
|
| CEP (m) | unknown | |
| Diam. (m) | 2.2/1.3 | |
| Height (m) | 32 | |
| L. W. (kg) | 80-85,000 | |
| Thrust (Kg f) | Effective: 30,432 per chamber Actual: 31,260 per chamber or Effective: 104,204 Actual: 170,040 |
|
| Burn time (sec.) | <330? | |
| Launch Acceleration (g's) | ~1.4-1.5 or 1.3 | |
| Thrust Chambers | 4, 1, 1 | |
| Stages | 2, 3 | |
| Type | LRICBM | |
| Stage 1 | ||
| Height (m) | ~16 | |
| Diameter (m) | ~2.2 | |
| Launch Weight (kg) | ~60,000-61,000 | |
| Launch Thrust (kg f) | ~102,880-104,000 | |
| Burn Time (sec.) | ~120-130 | |
| Fuel | TM-185 (20% Gasoline + 80% Kerosene) | |
| Oxidizer | AK-27I (27% N2O4 + 73% HNO3 + Iodium Inhibitor) | |
| Stage 2 | ||
| Height (m) | ~14 | |
| Diameter (m) | ~1.32-1.35 | |
| Launch Weight (kg) | ~15,200 | |
| Thrust (Kg f) | Effective: ~13,160 Actual: 13,300-13,380 |
|
| Burn Time (sec.) | 110 max | |
| Isp. (sec.) | Effective: 226 - SL Due to vanes steering drag loss of 4-5 sec. Actual: 230 - SL Vac: 264 | |
| Thrust Chambers | 1 | |
| Fuel | TM-185 (20% Gasoline + 80% Kerosene) | |
| Oxidizer | AK-27I (27% N2O4 + 73% HNO3 + Iodium Inhibitor) | |
| Propellant Mass (kg) | 12,912 | |
| Stage 3 | ||
| Height (m) | ~3-4 total package | |
| Diameter (m) | ~1.3-2.0 flared skirt type design | |
| Launch Weight (kg) | unknown | |
| Launch Thrust (kg f) | unknown | |
| Burn Time (sec.) | ~100 | |
| Propellant | Solid motor* | |
| * May have been derived from existing Chinese designs. | ||
The Shahab-5/Kosar is expected to have a range of 3,500-3,750 and 4,000-4,300 kilometers with a 1,000-750 kilogram warhead. Kosar means-Stream of eternal life in paradise. Israeli Intelligence calls this booster the Shahab-5 and Shahab-6. December 1996 news reports claimed that Iran is developing a 3,500-mile (5,632 kilometers) range missile called Shahab-6 that would be capable of reaching Europe. The technology for this system was cited as coming from Russia and North Korea. Reportedly the missile would become operational by the year 2,000, though others reports claim that Iran intends to complete the development of this system within five to ten years.
Quoting from the Oct. 1, 1998, The Washington Times, "Israeli, Prime Minister Mr. Benjamin Netanyahu said, "Iran is developing the Shahab-4 which can reach well into Europe, and the Shahab-5 and 6, which (will have the capacity) to reach the Eastern Sea board (of the United States)". The article went on to quote from the Blue-ribbon Congressional commission, headed by then former Defense Secretary Donald Rumsfeld.
"In addition to this Scud-based long-range ballistic missile program, Iran has acquired and is seeking major, advanced missile components that can be combined to produce ballistic missiles with sufficient range to strike the United States, "----." (1)
In testimony before the House Science Sub Committee on Space & Aeronautics July 14, 1999 as reported in The Washington Times p. A10. The Kosar is expected to have a range of 2,640-2,650 miles or (4,247.76--4,263.85 kilometers) with a 1,000lb. (453.6 kilogram) warhead. Presumably the Kosar/Shahab-5 will turn out to be an Iranian variant of the Taep'o-dong-2/NKSL-X-2.
The following information was provided from the July 16, 1999, The Washington Times article. Iran's Kosar launch vehicle also known as the Shahab-5 and 6, was suggested to be the Iranian variant of the North Korea's Taep'o-dong-2 booster. The new missile, was said to be undergoing design development with assistance from Russian aerospace technicians and state-run entities. It was suggested that it was powered with a version of Russia's storable liquid propellant RD-216 closed cycle two engine cluster in its booster first stage. The RD-216 is an Energomash engine originally used on the Skean/SS-5/R-14, IRBM, Saddler/SS-7/R-16, ICBM and Sasin/R-26 ICBM missiles developed during the cold war. It is still used on the C-1, Kosmos/SL-8 Russian space booster. This does suggest fairly strongly that Iran has acquired through elicit means the designs of the SS-5, RD-216 closed cycle storable liquid propellant rocket engines. This is questionable but gives some insight into the Taep'o-dong-2/Shahab-5 first stage design. It was based on new information suggesting there had been another rocket engine technology transfer from another Russian rocket engine entity Energomash. No further clarifying information on this has since surfaced. (2)
However this unproven rocket engine technology transfer from Russia to Iran, would not give Iran the engine documentation or the actual hardware. Nor did it give them the precise engineering drawings of each part or the materials and technology to produce and duplicate that technology. The only place where Iran could apply this engine technology it has acquired is in the Shahab-5 booster assuming they can even produce the engines. That will take them years beyond their intended design development cycle for those launch vehicles for them to assimilate that engine technology. They are left with no other alternative but to work with the available North Korean rocket engine technology, that they currently possess, and their rework of it to create the Shahab-5 program engines in cooperation with North Korea.
According to Kenneth R. Timmerman, President of Middle East Data Project, Inc. revealed the following information in the July 16, 1999, The Washington Times article that "Iran ---- regularly sends technical teams to attend North Korean missile launches. The Iranians travel in a specially equipped Boeing 707, packed with [Chinese supplied electronics as previously disclosed] missile telemetry and monitoring equipment, and --- be along for the show ----when North Korea tests its version of the Kosar, known as the Taep'o-dong-2 ----." (2)
The Washington Times, on September 22, 1999 quoted the Air Intelligence Agency, National Air Intelligence Center of Wright-Patterson Air Force Base, Ohio report entitled "Ballistic and Cruise Missile Threat." Which discussed several issues related to the Iranian missile programs. Those quoted comments from the NAIC publication were as follows:
"The Iranian defense minister has also stated that a Shahab-5 missile is in development. The Shahab-5 probably will have a longer range than the Shahab-4 and may be an IRBM. (Intermediate Range Ballistic missile)."
The article went on to quote from other officials to the affect that, a senior U. S intelligence officer had said in a briefing that, "Iran appears to be developing long-range missile "in a step-by-step approach to get to the ICBM's."
"Clearly they're progressing on a path,...more likely following this ... rather than a copy cat approach,".
It went on to suggest from the officials statements that the alternative approach for Iran to follow was to do what North Korea is doing to developed the Taep'o-dong-2 launch vehicle. They also added that the Iranians could follow the North Korean Taep'o-dong-2 design approach to what would be a LRICBM with a range limit of 3,400 miles (5,470.60 kilometers). They seemed to suggest that the Taep'o-dong-2 design approach was the better way to go. (3)
On February 9, 2000, The Washington Times, disclosed the following information,. "North Korea recently sold Iran a dozen medium range ballistic missile engines"---- (in November 1999). The [12] engines arrived in Iran on Nov. 21, (1999) after they were spotted being loaded aboard an Iran Air Boeing 747 cargo jet that left Suinan International Airfield about 12 miles north of-----Pyongyang (North Korea)".
These are the same engines used in No-dong MRBM. The article went on to state that the North Koreans continue to prepare to flight test the Taep'o-dong-2 launch vehicle. Then the article went on to describe several design alternatives for the use of the engines by Iran that could be used to create a Taep'o-dong-2 class booster. When considering the Shahab-5, and 6 class booster they could utilize a new first stage equipped with multiple No-dong engines and a second stage equipped with one or more No-dong engines with a solid motor third stage and warhead. The final concept was a new first stage equipped with a Russian engine toped with a single or multiple No-dong engines for a second stage with a solid motor and warhead. Some of these alternative concepts would certainly address the Taep'o-dong-2 mass fraction and stage aspect ratio problems but may have to wait for the introduction of the Shahab-6 launch vehicle. (4)
Mr. Robert Walpole National Intelligence officer for Strategic and nuclear programs, was further quoted in The Washington Times on Feb. 10, 2000 as stating,
"Those engines are critical to the Taep'o-dong Program,"-----of the North Korean's Long-range missile. "And They would be critical to the Shahab-3 program and any extensions of the Shahab-3 program".
--------" The CIA analysis also said North Korea has not stopped developing its Taep'o-dong long-range missile----". (5) NBC news added some more information on the Shahab-5 program on Feb 23, 2000. " Iran's Defense minister last year publicly acknowledged the development of the Shahab-4 originally called it a more capable ballistic missile than the Shahab-3 but later categorizing it as solely a space launch vehicle with no military application. Iran's defense minister also has publicly mentioned plans for a "Shahab-5""----. (6)
On September 21, 2000 during testimony before the U.S Senate Mr. Walpole National Intelligence officer for Strategic and nuclear programs discussed the Shahab-5 program in a general context.
Mr. Walpole "Iran's Defense minister announced the Shahab-4, originally calling it a more capable ballistic missile than the Shahab-3, but later categorizing it as a space launch vehicle with no military applications.
Tehran also mentioned plans for the Shahab-5 strongly suggesting that it intends to develop even longer-range systems in the near future.
Iran has displayed a mock-up satellite and space launch vehicle (IRIS), suggesting it plans to develop a vehicle to orbit Iranian satellites------- Most believe that Iran could develop and test a three-stage Taep'o-dong-2 type ICBM during this same time frame, possibly with North Korean assistance. -----ICBM booster capability and that a Taep'o-dong-type system tested as a space launch vehicle would be the shortest path to that goal.
TD-1 could be developed patterned after the NK approach or use it as a test bet to TD-2 etc. TD-1 is the test bed for the TD-2 larger technology.
Iran is insisting on the development of an indigenous effort, which takes longer to develop. (7)
The recently reported static test firing of the Taep'o-dong-2 first stage on the launch pad as reported in The Washington Times (8) failed to note that static test firings of what had to be the Taep'o-dong-2 rocket first stage could only be conducted in a vertical position as it was. However the engines could be static tested at a vertical position or horizontally or at 45 degrees from the vertical all of which are quite normal. Static test firings of the integrated engine and launch vehicle first stage rocket body could only be accomplished on the rebuilt Taep'o-dong-1 which is now the new Taep'o-dong-2 launch pad with it new gantry umbilical tower. The first stage of the Taep'o-dong-2 would have been set on the pad vertically firing down through the flame bucket to test the stage readiness for flight. That has clearly been done here so they are getting close to a flight of the Taep'o-dong-2/Shahab-5 class space booster once they tear-down the first stage engine cluster clean it up, reassemble and install it back in the first stage. This certainly explains the appearance of propellant tank trucks and support vehicles on the Taep'o-dong-2 launch pad along with a whole series of trucks recently observed in new imagery taken by Space Imaging of North Korea's Taep'o-dong launch site. What will follow both on Iran and North Korea's part remains to be seen.
Iran may have tested the IRIS booster last year that failed shortly after launch. Regardless, this launch could have been a flight test of the second and third stages of the Taep'o-dong-2/Shahab-5 space booster/ballistic missile.
On February 12, 1997 the Los Angeles, Times reported that Iran was getting help for its fledgling long range missile program from the Russians in the form of the SS-4 IRBM missile engine technology from NPO Trud. The suggested intelligence came from, the reports initially released in the Israeli press during January 1997. (9) The initial intelligence had come from Israeli Intelligence sources to Washington. Iran already had the Scud-B and Scud-C missiles as well as the North Korean No-dong MRBM. This assertion if true, would represent a potential violation of the Intermediate Range Nuclear Force Treaty (INF) and the 31 Nation (MTCR) Missile Technology Control Regime agreement by Russia. All of this apparently started in 1994 as Iran began to probe the potential possibilities for such a technology transfer within the former Soviet Union.
NPO-Trud stood accused of providing Iran design and production related information for the SS-4 IRBM, its RD-214 engines and selling equipment such as its guidance system and the means to produce the SS-4 missile.
This however makes no sense at all. Although NPO Trud had initially been accused of providing the SS-4's, RD-214 engine to the Iranians, in fact this particular engine was neither developed nor produced by NPO Trud. It is apparent that the sources of these suggestions were unfamiliar with the Russian entities developing and producing these rocket engines. It both brings into question the suggested SS-4 engine technology transfer and the SS-4 missile design technology greatly weakening the suggested intelligence validity. The simple fact of it is that NPO Trud never had anything to do with the SS-4 program period. It can be stated officially for the Russian Company that there is "No Foundation for the Claims," suggested in the U. S. public press. This company only developed Kerosene and LOX liquid propellant rocket engines NK-9, NK-9V for the strategic rocket program R-9/SS-8, ICBM and the GR-1/Scrag FOBS rocket that was not excepted for production or deployed service in the former Soviet Union. Trud also based on these ballistic missile engines developed the N1-L3 Soviet moon rocket engine NK-15, NK-15V, NK-9V/NK-19V, NK-21 that we know today as the NK-33, NK-43, NK-39, and NK-31 now being offered by Aerojet. The NK-33 and NK-43 engines are to be used by Kistler's commercial satellite reusable booster and on the Japanese J-2 booster under development. The NK-33 is one of the best rocket engines in the world today truly the crown jewel of Russian rocket engine technology.
NPO Trud - Now the Russian, Samara based Joint Stock Company Called, N. D. Kuznetsov Research and Engineering Complex, JSC was accused by the Western press reports in 1997 of accepting a $7,000,000. Contract offered by Iran to jointly develop a "Gas Pumping," gas turbine for a gas pumping station project.
The actual story is that this discussion with the Iranians took place in 1994 and that Trud was uninterested in the project. This incident did not take place in 1997 as suggested in the Russian and Western Press. The Iranian's had in fact repeatedly requested that a "Gas Pumping," turbo-pump machinery joint venture project be started. Iran made the contact proposal with out giving the specifications. NPO Trud became suspicious when the Iranians refused to provide the specifications for the machinery to be developed that they were asking for under the contract proposal.
Once Trud got the specifications, the Russian company realized that the Iranian's had actually tried to get Trud to give the Iranians missile technology in the form of new turbo-pump that were nothing less than rocket engine turbo-pump specifications. NPO Trud notified the Russian Government. The Project was both rejected by NPO Trud and thwarted by the Russian Government putting an end to the contract consideration in 1997. On this one occasion the Missile Technology Control Regime had worked in Russia. NPO Trud was replaced in 1994 by a Joint Stock Company, Kuznetsov R & E C. This is why the U.S. Government brought no sanctions against the Russian Company that replaced NPO Trud. Trud now Kuznetsov was and still is more interested in its renewed NK Russian Rocket engine developments for application to Russian launch vehicles and its new commercial aircraft engine because of its large commercial business value.
The critical question that must be addressed is why were the Iranian's trying to get this new turbo-pump, machinery from the Russians and what did it reveal? What was their intended use? Circumstantial evidence suggest that the Taep'o-dong-2/NK-SL-X-2 first stage engine probably uses four No-dong thrust chambers with a new single turbo-pump to create a new first stage engine. The alternative is to use a cluster four No-dong engines with their separate Turbo-pumps and trying to synchronize their ignition and operation. There is also the added design problem of fitting those four No-dong engines with their separate pumps in the already established diameter of the launch vehicle airframe. Probably this new turbo-pump, machinery was developed jointly by Iran, North Korea and the Peoples Republic of China under technology-sharing arrangements that evolved in the mid-1990's. Before developing this technology with the North Koreans, the Iranian's evidently attempted to obtain this technology from NPO Trud but failed.
This is the critical bit of information that potentially links the Taep'o-dong-2 missile program with the Iranian Shahab-5 and Shahab-6 missile programs regardless of the lack of public information confirming this apparent reality. Contrary to the Rumsfeld report the No-dong is now known to use one thrust chamber that appears to be a modification of the original Isayev OKB S-2.713 storable liquid propellant, 25,720 kg thrust, rocket engine from the Soviet SS-N-4 SLBM program received during the Gorbachev era. The engine is probably labeled S-2.713M, deletes the four vernier thrust chambers and increases the thrust of the main thrust chamber to 26,760 kg. force with accommodations for a fuel change. (See the North Korean No-dong section for details)
The Taep'o-dong-2 design is not optimized for its performance potential. That is the launch vehicle engineering design aspect ratio, its length to diameter ratio and its mass fraction stage mass relationship has the potential to create in flight structural problems. This is because it is carrying much more mass than it should because of its design characteristics, which greatly reducing it performance potential. North Korea has probably had considerable trouble adapting the structurally heavy No-dong second stage to the new Taep'o-dong-2 first stage. Iran is also faced with the same engineering issues.
These problems reflects on the obvious poor engineering design decisions both in its structural design and imposed performance penalties verses the PRC Chinese DF-4/CSS-3, 3A design as is self evident when studying the designs and the summery range performance characteristics. It is also emphasized in their design differences shown in the accompanying illustrations. Thus its performance due to structural requirements will suffer accordingly. (See the range performance data shown in North Korean missile overview chart.)
Whether Iran has adapted the North Korean Taep'o-dong-2 design for its Shahab-5 and Shahab-6 is unclear at this time. It is strongly suspected that Iran will utilize the Taep'o-dong-1 type design for its Shahab-4 satellite launch vehicle design so that it also could be deployed as an Iranian derivation of the Taep'o-dong-1 strategic ballistic missile with a performance similar to that of the SS-4. Yet this also remains highly questionable based on the trends seen so far. In fact the IRIS launch vehicle payload has been displayed as a two stage vehicle the first stage of which is clearly a No-dong with a solid motor second stage. The exception here is that this would have to be the second and third stage of a larger Taep'o-dong-2/NKSL-X-2 class launch vehicle to be able to launch a satellite. If the IRIS vehicle was a Scud-B or Scud-C based derivation it would have to be a Taep'o-dong-1 class space booster in any case. Indeed Iran has suggested that it's Shahab-4 will be the last rocket it will develop even though there are suggested evidence to the contrary. The Shahab-4 program is now believed to have been at least temporally shelved. (see the Shahab-4 section for more information.)
The first stage of the Taep'o-dong-2 is said to bear a close resemblance to the Chinese CSS-2 and CSS-3 first stage, but is slightly smaller. Other reports suggest that the first stage of the Taep'o-dong-2 is almost identical to the Chinese CSS-2. The diameter of the Taep'o-dong-2's/NKSL-X-2's first stage is apparently close to 2.2 meters verses the 2.25 meters diameter of the CSS-2 missile. The Taep'o-dong-2/NKSL-X-2 is also slightly shorter in length. This indicates that the Taep'o-dong-2/NKSL-X-2 may have an inferior performance capability compared to the Russian SS-5 with its 2.4 meter body diameter and to a degree the PRC CSS-2 missiles.
Again in July of 1999, it was suggested that the Iranian Shahab-5/IR-SL-X-3 and or Shahab-6/IRSL-X-4 first stage utilized a Russian SS-5/R-14, NPO Energomash RD-216 closed cycle engine cluster of two engines with four main thrust chambers, however, this report is misinformed. The SS-5 is substantially larger than the CSS-2. The CSS-2 also uses a totally different and less efficient open cycle four thrust chamber engine which is very different from the RD-216 closed cycle engine of two main thrust chambers and one turbine exhaust thrust chamber.
Even if the SS-4 and SS-5 rocket airframes and or engines are involved where are the second and third stages for these launch vehicles coming from? It takes many years to develop and adapt such upper stages to these first stages. That kind of development infrastructure apparently simply does not exist as a seasoned industrial base in Iran. This technology has to come from existing Middle East, North Korean and Chinese No-dong, Scud based systems technology with its common heritage.
Following the North Korean design philosophy of looking at what hardware does exist logically dictates that the SS-4 first stage could be topped with a Scud-B/C for a second stage and perhaps a solid motor third stage based on the SAM-2 technology. This was in fact considered in the early ballistic missile program of the Soviet Union but it was abandoned. The SS-5 first stage could use a No-dong missile as a second stage that in turn could be topped by a larger solid motor third Stage. Unfortunately the performance of these SS-4 and SS-5 combinations with upper stages based on Scud technology would also suffer like the North Korean designs do but their range performance would be somewhat greater than the North Korean designs for Taep'o-dong-1 and Taep'o-dong-2. All suggested public evidence that Iran is using the SS-4 and SS-4 missile is highly questionable based on the previous discussions in this and the Shahab-4 and Shahab-6 sections.
The total circumstantial evidence tends to suggest that Iran is not developing the SS-4 and the SS-5 missiles. It does strongly suggest that they are attempting to develop a derivation of the North Korean Taep'o-dong-1 and Taep'o-dong-2 missiles as a part of its Shahab-4 and Shanab-5 and 6 "building block scheme," of space booster, missile development. It is also emphasized in their design differences shown in the accompanying illustrations. It can also be assumed that if Iran develops all of these large missile system that they are credited to be developing that it will result in Iran acquiring the skills it needs to manage its use of the applied Sciences and technology in ballistic missile and space development. Thus it could be expected to make its own indigenous modifications to the foreign acquired missile designs and eventually giving it an autonomous larger systems development capability.
During 1999 preparations were detected for the launch of the larger Taep'o-dong-2 missile. Beginning in May 1999, US Intelligence picked up indications that the Taep'o-dong-1 launch site was being modified to accommodate the Taep'o-dong-2. Compared to the previous pad gantry umbilical tower (with a height of about 22 meters), the new pad gantry umbilical tower is 1.5 times taller, standing about 33 meters tall. These modifications were nearly complete as of late July 1999, and as of early August 1999 it appeared that the Taep'o-dong-2 vehicle was already complete and was stored near the launch pad. However, it had not been transported over to the launch pad. It is said that it would take two days to assemble the missile on the launch pad before checking it out and then load liquid fuel propellants in the launch vehicle propellant tanks from tanker trucks. By year's end these activities were abandoned with no launch resulting.
This certainly indicates, with relative certainty, that the Taep'o-dong-1 launch was not merely carried out for a propaganda statement opportunity to place a satellite in Earth orbit. It was also used as a pathfinder to prove the launch vehicle "building block approach" for the future follow on larger launch vehicle Taep'o-dong-2. This could also indicate that the Taep'o-dong-1 program was only intended to be a short lived limited proof of principal program from which some limited economic benefit from third world countries may have been envisioned by the North Korean military industrial leadership.
According to some media reports, North Korea has conducted three or four static test firings of Taep'o-dong missile engines, between December 1999 and January 2000, at Musudan Base in North Hamgyong Province. Some of these test firings no doubt involved the static test firing development of the Taep'o-dong-2 first stage four thrust chamber first stage engine. This in turn lead to the more recent late June early July 2001 vertical static test firing of the Taep'o-dong-2 first stage on the launch pad as reported in The Washington Times. (8, 10).
If as it does appear circumstantially that Iran and North Korea are cooperating both ways on the larger higher performance Taep'o-dong-2 class system then what can be expected in the near future? Will Iran in fact flight test the Taep'o-dong-2/Shahab-5 class booster for North Korea and Iran in place of North Korea? This is because North Korea can not afford to do so because of its international agreements not to flight test its ballistic missiles.
Surely the political leadership of Iran recognized the geopolitical impact of Iran attempting to launch a satellite and perhaps succeeding would create considerable pressure on their regime thus the decision to favor the Shahab-5 more capable system over the shelved Shahab-4 system can be understood. For many years now this is exactly what I thought they would do.
But it must also be stated here that the Taep'o-dong-2/Shahab-5/6 class system is even less viable as a strategic deployable ballistic missile but is a better space booster than the marginal performance Taep'o-dong-1 booster. Both North Korea and Iran seem to be using the "building block approach," to developing what can be said to be space boosters that could if they choose be revised and deployed as ballistic missiles ultimately leading to a Limited Range ICBM, within the next five or ten years. Eventually through indigenous follow on development it could lead to a Full Range ICBM which they are not now pursuing. In general the performance attributed to the various missile systems appear to far exceed a realistic performance with a legitimate strategic lethal payload mass to the continental United States. However they are a legitimate lethal threat to the European, Asian, Middle East, and African. It begs the question of just what are they aiming these missiles at both strategically and geopolitical policy wise. They are however through this building block approach developing the technological and management of Industrial, Science & Technology, base that they do not fully have in place now, which could lead to a Full Range ICBM development in the next 7-12 years. Is it inconceivable for North Korea to ship the jointly developed and tested Taep'o-dong-2 booster first stage to Iran where it would be mated with the Iranian Shahab-3/IRIS second and third stages of the booster to launch a satellite already announced into Earth orbit? The satellites launch has perhaps slipped to the time frame of 2003-2005. Only time will answer this suggestion.