Question: How many was the N1 unsuccessfully tested?
About the article "Space Race", section "Soviet Moon program".

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The Sala N1 or N1 Sala was a single seat, span competition glider built in Italy in 1937.
Only one was constructed. 
Western Cape.
The N1 begins in central Cape Town at the northern end of Buitengracht Street outside the entrance to the Victoria & Alfred Waterfront.
The first section of the N1 is shared with the beginning of the N2; it is a four-lane elevated freeway that runs along a strip of land between the city centre and the Port of Cape Town.
On the eastern edge of the city centre the two roads split, and the N1 turns east as Table Bay Boulevard, passing the Ysterplaat Air Force Base and Century City before the N7 intersects it on its own way out of the city towards Namibia.
Major improvements have been made to the Koeberg Interchange, where the N1 meets the M5, one of the main arterial routes linking Milnerton with the Southern Suburbs.
The N1 then heads through the suburbs of Goodwood and Bellville, where the R300 terminates at it, before heading towards Paarl.
At Paarl, the freeway ends, and the N1 is tolled as it passes through the Huguenot Tunnel running underneath the Du Toitskloof Mountains; the tunnel was opened in the late 1980s to replace the old Du Toitskloof Pass running over the mountain.
After emerging from the tunnel, the N1 winds through the Molenaar River Valley (which is a short dual carriageway section) before emerging from the valley and heading towards Worcester.
From Worcester, the route heads through the Hex River Valley and then enters the Karoo by ascending the Hex River Pass.
Currently only the section of the N1 passing through the Huguenot Tunnel is tolled, although there are plans to toll the N1 from the junction with the R300, roughly to De Doorns.
This would allow for upgrading of the N1, most especially the opening and construction of the Northern Bore of the Huguenot Tunnel so that two lanes of traffic could pass in each direction through the tunnel, and the building of grade separated junctions along the N1 through Worcester.
Although the town is bypassed, there are a number of traffic lights on the N1 through Worcester.
From the top of the pass, the N1 passes Touws River and Matjiesfontein before passing through Laingsburg, then heads towards Beaufort West.
The 200 km section between Laingsburg and Beaufort West is notorious for claiming many lives in fatigue-related accidents; also, the N1 begins to turn towards the north-east along this stretch of road.
Just before Beaufort West, the N12 from George meets the N1; the N12 shares the N1 route through Beaufort West and for the next 80 km before splitting at Three Sisters.
The N12 later meets the N1 again in Johannesburg, making the N12 an alternative route to the N1, passing through Kimberley instead of Bloemfontein.
Although parts of the N12 between Warrenton and Klerksdorp are in poor condition (although in process of being upgraded), the N1 from Bloemfontein onwards is tolled while the N12 is toll-free.
Whereas the N12 also passes through most of the towns en route to Johannesburg, the N1 bypasses every town between Beaufort West and Johannesburg.
The N1 briefly crosses into the Northern Cape at Three Sisters for a few kilometres before crossing back into the Western Cape, and remains in the Western Cape until just after its intersection with the R63, where re-enters the Northern Cape. 
The N-1 was a heavy lift rocket intended to deliver payloads beyond low Earth orbit, acting as the Soviet counterpart to the NASA Saturn V rocket.
This heavy lift booster had the capability of lifting very heavy loads into orbit, designed with manned extra-orbital travel in mind.
Development work started on the N-1 in 1959.
Its first stage is the most powerful rocket stage ever built.
The N1-L3 version was developed to compete with the United States Apollo Saturn V to land a man on the Moon.
The basic N1 launch vehicle had three stages, which was to carry the L3 lunar payload into low Earth orbit.
The L3 contained an Earth departure stage and a lunar landing assist stage, in addition to the single-cosmonaut LK Lander spacecraft, and a two-cosmonaut Soyuz 7K-LOK lunar orbital spacecraft.N1-L3 was under-funded and under-tested, and started development in October 1965, almost four years after the Saturn V. The project was badly derailed by the death of its chief designer Sergei Korolev in 1966.
Each of the four attempts to launch an N1 failed; during the second launch attempt the N1 rocket crashed back onto its launch pad shortly after liftoff and exploded, resulting in one of the largest artificial non-nuclear explosions in human history.
The N1 program was suspended in 1974, and in 1976 was officially canceled.
Along with the rest of the Soviet manned Moon programs, the N1 was kept secret almost until the collapse of the Soviet Union in December 1991; information about the N1 was first published in 1989. 
The Soviet Union had planned to divide their lunar program into two separate manned programs: circumlunar flights in 1967 and lunar landings from 1968.
The circumlunar missions were to be launched by a UR-500 rocket, later known as the Proton.
The cosmonauts would be flown to the Moon in the Soyuz 7K-L1 (Zond), which made four unsuccessful unmanned flights between 1967 and 1970.
One flight of the Zond was, however, successful and returned its non-human passengers (tortoises) to Earth; had it been used for a manned circumlunar mission, the flight would have carried two cosmonauts.
The Soviet lunar landing missions would use spacecraft derived from the Soyuz 7K-L1.
The orbital module (Soyuz 7K-L3), the ""Lunniy Orbitalny Korabl"" (LOK), had a crew of two.
The LOK and a separate lunar lander, the ""Lunniy Korabl"" (LK), had 40% of the mass of the Apollo CSM/LM due to the launch vehicle's capabilities.
The launch vehicle would have been the N1 rocket, which was roughly the same height and takeoff mass as the American Saturn V, exceeded its takeoff thrust by 28%, and yet had roughly half the TLI payload capability.
The N1 was unsuccessfully tested four times, exploding each time due to problems with the first stage's thirty engines.
The Soviet leadership cancelled the program in 1970 after the first two successful American Moon landings.
After the Orange River crossing, the N1 makes a direct line for Bloemfontein, heading in a more northerly direction.
The N1 from Colesberg to Bloemfontein is highly significant because it was the first single-carriageway freeway built in South Africa.
The bridges with the interchanges at Edenburg and Trompsburg show the ambitious plans for this road as a dual-carriage freeway.
Just before reaching Bloemfontein, the N6 from East London terminates where it meets the N1.
This intersection marks the beginning of the Bloemfontein Western Bypass, which is the first freeway section on the route since Paarl.
The N8 WEST from Kimberley intersects with the N1 bypass, joining it for 3 km, before heading EAST through the central parts of Bloemfontein and then to Maseru in Lesotho, The N1 is signed as a toll road from the N6 interchange until its end at Beit Bridge.
The N1 becomes a single carriageway freeway a few kilometres north of Bloemfontein after passing the R30 to Brandfort; however, construction work is in progress to extend the freeway for another 20 km by building a second carriageway.
Once the freeway ends, the road will be a single carriageway but with two lanes in each direction until 5 km before the toll plaza at Verkeerdevlei, halfway between Bloemfontein and Winburg.
Initial plans were for the N1 from Winburg to Bloemfontein to be a dual-carriageway freeway.
At Winburg, the N5 splits from the N1, which bypasses the north of Lesotho before its own termination at the N3 in Harrismith.
Many motorists from Cape Town heading for Durban travel the N1 to Winburg, and then N5 to Harrismith as an alternative to reach Durban.
This is due to the much better quality of this route compared with the N2, especially between Port Shepstone and Grahamstown.
The N1 continues north and passes through Ventersburg before reaching Kroonstad.
There the R34 joins the N1 from Welkom.
There is a short dual carriageway freeway bypass of Kroonstad, before the N1 heads towards the Vaal River and Gauteng.
Just before passing into Gauteng at the Vaal River, the N1 becomes a dual-carriageway freeway and features another toll plaza.