Editing Falcon 1 (section)

===Fourth flight===
[[Image:Spacex 067.jpg|thumb|The second-stage [[Kestrel (rocket engine)|Kestrel engine]] glows red-hot during Falcon 1's fourth launch and first successful orbital flight.]]
{{Main|Ratsat}}
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 [[Implosion (mechanical process)|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.<ref>{{Cite book|last=Berger|first=Eric|title=Liftoff|publisher=[[William Morrow and Company]]|year=2021|isbn=978-0-06-297997-1|pages=181–197}}</ref> 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 (spaceflight)|boilerplate]] spacecraft into [[low Earth orbit]].<ref name="SpaceX Falcon1 Flight4"/> It was Falcon&nbsp;1's first successful launch and the first successful [[geocentric orbit|orbital]] launch of any [[private spaceflight|privately funded and developed]], fully liquid-propelled carrier rocket.<ref name=sfn20080928/>

The launch occurred from [[Omelek Island]], part of the [[Kwajalein Atoll]] in the [[Marshall Islands]].<ref name="MSC">{{cite web|url=http://www.spaceflightnow.com/falcon/004/status.html|title=Mission Status Center|last=Ray|first=Justin|date=September 28, 2008|publisher=Spaceflight Now|access-date=September 28, 2008}}</ref> Liftoff occurred at 23:15&nbsp;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.<ref name="SpaceX updates">{{cite web|url=http://www.spacex.com/F1-004.php|title=Falcon 1 Flight 4|last=Musk|first=Elon|date=September 27, 2008|publisher=SpaceX|access-date=September 28, 2008|url-status=dead|archive-url=https://web.archive.org/web/20110725225434/http://www.spacex.com/F1-004.php|archive-date=July 25, 2011}}</ref> 9 minutes 31 seconds after launch, the second-stage engine shut down, after the vehicle reached orbit.<ref name="MSC"/> The initial orbit was reported to be about 330 × 650&nbsp;km.<ref name=sfn20080928>
{{cite web |last=Clark|first=Stephen |title=Sweet Success at Last for Falcon 1 Rocket |date=September 28, 2008 |publisher=Spaceflight Now |url=http://www.spaceflightnow.com/falcon/004/index.html |access-date=April 6, 2011 |quote=the first privately developed liquid-fueled rocket to successfully reach orbit}}</ref>
Following a coast period, the second stage restarted and performed a successful second burn, resulting in a final orbit of 621 × 643&nbsp;km × 9.35°.

The rocket followed the same trajectory as the previous flight, which failed to place the [[Trailblazer (satellite)|Trailblazer]], [[NanoSail-D]], [[PRESat]] and [[Celestis|Celestis Explorers]] spacecraft into orbit. No major changes were made to the rocket, other than increasing the time between first-stage burnout and second-stage separation. This minor change addressed the failure seen on the previous flight, recontact between the first and second stages, by dissipating residual thrust in the first-stage engine before separating them.<ref name="F3">{{cite web|url=http://www.space.com/news/080806-spacex-falcon1-update.html|title=SpaceX Traces Third Rocket Failure to Timing Error|last=Malik|first=Tariq|author2=Berger, Brian |date=August 6, 2008|publisher=Space.com|access-date=September 28, 2008}}</ref><ref name="SFN preview">{{cite web|url=http://www.spaceflightnow.com/falcon/004/080927preview.html|title=SpaceX to launch its fourth Falcon 1 rocket on Sunday|last=Clark|first=Stephen|date=September 27, 2008|publisher=Spaceflight Now|access-date=September 28, 2008}}</ref><ref>{{Cite news |issn=0362-4331 | last = Schwartz | first = John | title = Private Company Launches Its Rocket Into Orbit | work = [[The New York Times]] | access-date = September 29, 2008 |date = September 29, 2008 | url = https://www.nytimes.com/2008/09/29/science/space/29launch.html?_r=1&ref=us&oref=slogin}}</ref>

Ratsat and the attached second stage are still in orbit as of 2021.<ref>{{cite web|url=http://stuffin.space/?intldes=2008-048A&search=Falcon%201|website=stuffin.space|access-date=January 22, 2021|title=Stuff in Space}}</ref>