September 28, 2008
By the last Sunday of September 2008, SpaceX was a company with three spent rockets in the Pacific and money for roughly one more try. Elon Musk's fortune was draining into two struggling ventures at once, and the eight-week-old wreckage of Flight 3 still stung: a failure measured in seconds would now decide whether privately developed orbital rockets had a future at all. On Omelek Island, a speck of coral in Kwajalein Atoll, a small launch crew fuelled the fourth Falcon 1 while around 500 employees crowded around screens in Hawthorne, California.
Flight 3 had died of an upgrade: the new Merlin 1C engine, regeneratively cooled, produced a wisp of residual thrust after shutdown, just enough to push the first stage back into the second at separation. The entire fix was to wait a few extra seconds before staging. No customer would gamble a satellite on Flight 4, so the rocket carried RatSat, a 165-kilogram aluminium mass simulator named after three SpaceX structures engineers. Even reaching the pad had been a drama: the first stage nearly buckled inside the C-17 ferrying it across the Pacific when cabin pressure changed, saved by engineers who scrambled to open its valves in flight.
At 23:15 UTC on 28 September 2008, Falcon 1 lifted off through a clean countdown. The Merlin burned true, staging was crisp, the fairing fell away, and the webcast audience watched Earth curve into view behind the second stage's Kestrel engine. Nine and a half minutes after leaving the island, the vehicle shut down in orbit. It was the first privately developed liquid-fuelled rocket ever to circle the Earth, built by a team of a few hundred people on private money, and in Hawthorne the room simply erupted.
Musk, addressing his employees minutes later, called it one of the best days of his life. The timing saved the company: that December, NASA awarded SpaceX a $1.6 billion contract to resupply the International Space Station, and within four years Dragon capsules were berthing at the ISS. Falcon 1 itself flew only once more, delivering Malaysia's RazakSAT in July 2009, before retiring in favour of Falcon 9. Every booster SpaceX has landed since traces its lineage to the rocket that finally flew on the fourth try.
“As the saying goes, the fourth time's the charm. This is one of the best days of my life.”
Launch
28 Sep 2008, 23:15 UTC
Launch site
Omelek Island, Kwajalein Atoll
Payload
RatSat, 165 kg mass simulator
Flight
4th Falcon 1 launch, first success
Final orbit
approx. 621 x 643 km
Turnaround from Flight 3 failure
8 weeks
The payload, RatSat, was an aluminium slab named for SpaceX structures engineers Ray Amador, Jeff Richichi and Chris Thompson; it stayed bolted to the second stage and remained in orbit for years.
The fix for the Flight 3 failure was almost absurdly simple: wait a few extra seconds between first-stage shutdown and separation, so the Merlin 1C's residual thrust could fade.
The Flight 4 first stage nearly imploded inside the C-17 transport carrying it to Kwajalein when cabin repressurisation buckled its tank; engineers crawled into the cargo bay to open valves and saved it.
Musk has said he originally had funding for only three attempts; the fourth flight flew on scraped-together resources, with fresh investment closing just weeks before launch.
Less than three months later, NASA awarded SpaceX a $1.6 billion ISS cargo resupply contract; the company that nearly died that September was berthing Dragon capsules at the station by 2012.
Flight 4 proved that a privately developed and privately financed rocket could reach orbit, something only national programs had ever done. It rescued SpaceX from collapse at the very moment NASA was deciding whether commercial providers could be trusted with space station cargo, and the $1.6 billion CRS contract that followed institutionalised the commercial model. The line from this 165-kilogram dummy payload runs directly to Falcon 9, reusable boosters, commercial crew and the launch market's transformation; the modern commercial space era effectively begins with this flight.
SpaceX, CC BY-SA 3.0, via Wikimedia Commons
Official source