First flight
The maiden flight of the Falcon 1 was postponed several times because of various technical issues with the new vehicle. Scheduling conflicts with a Titan IV launch at Vandenberg AFB also caused delays and resulted in the launch moving to the Reagan Test Site in the Kwajalein Atoll. The maiden launch was scheduled for October 31, 2005,[51] but was held off, then rescheduled for November 25,[52] which also did not occur. Another attempt was made on December 19, 2005, but was scrubbed when a faulty valve caused a vacuum in the first stage fuel tank, causing the walls of the tank to sunk inward, resulting in structural damage. After replacing the first stage, Falcon 1 launched Saturday, March 25, 2006, at 09:30 local time. The DARPA payload was the United States Air Force Academy's FalconSAT–2, which would have measured space plasma phenomena.
The launch took place on Saturday, March 24, 2006, at 22:30 UTC, from the SpaceX launch site on Omelek Island in the Marshall Islands. It ended in failure less than a minute into the flight because of a fuel line leak and subsequent fire. The vehicle had a noticeable rolling motion after liftoff, as shown on the launch video, rocking back and forth a bit, and then at T+26 seconds rapidly pitched over. Impact occurred at T+41 seconds onto a dead reef about 250 feet from the launch site. The FalconSAT–2 payload separated from the booster and landed on the island, with damage reports varying from slight to significant.[53] SpaceX initially attributed the fire to an improperly tightened fuel-line nut. A later review by DARPA found that the nut was properly tightened, since its locking wire was still in place, but had failed because of corrosion from saltwater spray.
SpaceX implemented numerous changes to the rocket design and software to prevent this type of failure from recurring, including stainless steel to replace aluminum hardware and pre-liftoff computer checks that increased by a factor of thirty.[54][55]
Second flight
The second test flight was originally scheduled for January 2007, but was delayed because of problems with the second stage. Before the January launch date, SpaceX had stated earlier potential launch dates, moving from September 2006 to November and December. In December the launch was rescheduled for March 9, but delayed because of range availability issues caused by a Minuteman III test flight, which would re-enter over Kwajalein. The launch attempt on March 19 was delayed 45 minutes from 23:00 GMT because of a data-relay issue, and then scrubbed 1 minute 2 seconds before launch at 23:45 because of a computer issue, whereby the safety computer incorrectly detected a transmission failure caused by a hardware delay of a few milliseconds in the process. March 20 attempt was delayed 65 minutes from an originally planned time of 23:00 because of a problem with communications between one of the NASA experiments in the payload and the TDRS system.
The first launch attempt on March 21, 2007, was aborted at 00:05 GMT at the last second before launch and after the engine had ignited. It was, however, decided that another launch should be made the same day. The rocket successfully left the launch pad at 01:10 GMT on March 21, 2007, with a DemoSat payload for DARPA and NASA. The rocket performed well during the first-stage burn. However, during staging, the interstage fairing on the top of the first stage bumped the second-stage engine bell.[56] The bump occurred as the second-stage nozzle exited the interstage, with the first stage rotating much faster than expected (a rotation rate of about 2.5°/s vs. expected rate of 0.5°/s maximum), thereby making contact with the niobium nozzle of the second stage.
Third flight
SpaceX attempted the third Falcon 1 launch on August 3, 2008 (GMT) from Kwajalein.[60] This flight carried the Trailblazer (Jumpstart-1) satellite for the US Air Force,[61] the NanoSail-D and PREsat nanosatellites for NASA and a space burial payload for Celestis.[62] The rocket did not reach orbit. However, the first stage, with the new Merlin 1C engine, performed perfectly.[63]
When preparing for launch, an earlier launch attempt was delayed by the unexpected slow loading of helium onto the Falcon 1; thus exposing the fuel and oxidizer to the cryogenic helium, rendering the vehicle in a premature launch state. Still within the specified window, the launch attempt was recycled, but aborted half a second before lift-off because of a sensor misreading. The problem was resolved, and the launch was again recycled. With 25 minutes left in the launch window, the Falcon 1 lifted off from Omelek Island at 03:35 UTC. During the launch, small vehicle roll oscillations were visible.
Fourth flight
Following the three prior failures, the SpaceX team assembled the fourth rocket using available parts in six weeks as a last chance for the company. A Boeing C-17 Globemaster III was chartered to quickly deliver the rocket, but along the way, the rocket partially imploded when repressurization exceeded what the SpaceX team had expected from the C-17's manual and the rocket had to undergo emergency repairs to be saved.[68] Despite the challenges, the fourth flight of the Falcon 1 rocket successfully flew on September 28, 2008, delivering a 165-kilogram (363-pound) non-functional boilerplate spacecraft into low Earth orbit.[47] It was Falcon 1's first successful launch and the first successful orbital launch of any privately funded and developed, fully liquid-propelled carrier rocket.
The launch occurred from Omelek Island, part of the Kwajalein Atoll in the Marshall Islands.[69] Liftoff occurred at 23:15 UTC on September 28, 15 minutes into a 5-hour launch window. If the launch had been scrubbed, it could have been conducted during the same window until October 1.[70]
Fifth flight
SpaceX announced that it had completed construction of the fifth Falcon 1 rocket and was transporting the vehicle to the Kwajalein Atoll launch complex where it was to be launched on April 21, 2009, which would be April 20, 2009, in the United States.[76] Less than a week before the scheduled launch date, Malaysian news reported that unsafe vibration levels had been detected in the rocket and repairs were expected to take about six weeks.[77] On April 20, 2009, SpaceX announced in a press release that the launch had been postponed because of a potential compatibility issue between the RazakSAT spacecraft and the Falcon 1 launch vehicle. A concern had been identified regarding the potential impact of predicted vehicle environments on the satellite.[78] On June 1, SpaceX announced that the next launch window would open Monday, July 13 and extend through Tuesday, July 14, with a daily window to open at 21:00 UTC (09:00 local time[79]).
The launch on Monday, July 13 was successful, placing RazakSAT into its initial parking orbit. Thirty-eight minutes later, the rocket's second-stage engine fired again to circularize the orbit. The payload was then successfully deployed.
End of Program
Following the fifth flight, future launches of Falcon-1 were postponed, and eventually cancelled, and the vehicle decommissioned from service,[82] with SpaceX stating "We could not make Falcon 1 work as a business." Launches which had been booked onto Falcon-1 were moved to other vehicles or rebooked as Falcon-9 rideshare payloads.[83]
